Semiconductor device

Abstract

Provided is a semiconductor device occupying a small area. The semiconductor device includes a first conductive layer, a second conductive layer on the first conductive layer, a first insulating layer on the second conductive layer, a semiconductor layer and a third conductive layer on the first insulating layer, a second insulating layer on the semiconductor layer and the third conductive layer, and a fourth conductive layer on the second insulating layer. At least a portion of the second conductive layer is in contact with a top surface of the first conductive layer, the semiconductor layer is in contact with the top surface of the first conductive layer, a side surface of the second conductive layer, a side surface of the third conductive layer, and a side surface of the first insulating layer, and the fourth conductive layer overlaps the semiconductor layer via the second insulating layer.

Description

Technical Field

[0001] One embodiment of the present invention relates to a semiconductor device and a method for manufacturing the same. One embodiment of the present invention relates to a transistor and a method for manufacturing the same. One embodiment of the present invention relates to a display device including a semiconductor device.

[0002] Note that one embodiment of the present invention is not limited to the above-mentioned technical field. As an example of the technical field of one embodiment of the present invention, a semiconductor device, a display device, a light-emitting device, a power storage device, a storage device, an electronic device, a lighting device, an input device (such as a touch sensor), an input-output device (such as a touch panel), and a driving method or a manufacturing method of the above-mentioned device can be cited.

[0003] In this specification, etc., a semiconductor device refers to a device that utilizes semiconductor characteristics, and refers to a circuit including a semiconductor element (transistor, diode, photodiode, etc.) and a device including the circuit. In addition, a semiconductor device refers to all devices that can function by utilizing semiconductor characteristics. For example, as an example of a semiconductor device, there are integrated circuits, chips with integrated circuits, and electronic components that contain chips in packages. In addition, sometimes storage devices, display devices, light-emitting devices, lighting devices, and electronic devices themselves are semiconductor devices, or include semiconductor devices. Background Art

[0004] Semiconductor devices including transistors are widely used in electronic devices. For example, by reducing the occupied area of ​​transistors in display devices, the pixel size can be reduced to achieve high definition. Therefore, there is a demand for miniaturization of transistors.

[0005] As devices requiring a high-definition display apparatus, for example, devices for virtual reality (VR: Virtual Reality), augmented reality (AR: Augmented Reality), alternative reality (SR: Substitutional Reality), or mixed reality (MR: Mixed Reality) are being actively developed.

[0006] As a display device, a light-emitting device having, for example, an organic EL (Electro Luminescence: electroluminescence) element or a light-emitting diode (LED: Light Emitting Diode) is being developed.

[0007] Patent Document 1 discloses a high-definition display device using an organic EL element. [Prior technical literature] [Patent Document]

[0008] [Patent Document 1] International Patent Application Publication No. 2016 / 038508 Summary of the invention Technical problem to be solved by the invention

[0009] One of the purposes of one embodiment of the present invention is to provide a micro transistor. In addition, one of the purposes of one embodiment of the present invention is to provide a transistor with a small channel length. In addition, one of the purposes of one embodiment of the present invention is to provide a transistor with a large on-state current. In addition, one of the purposes of one embodiment of the present invention is to provide a transistor with good electrical characteristics. In addition, one of the purposes of one embodiment of the present invention is to provide a semiconductor device with a small footprint. In addition, one of the purposes of one embodiment of the present invention is to provide a semiconductor device with low wiring resistance. In addition, one of the purposes of one embodiment of the present invention is to provide a semiconductor device or display device with low power consumption. In addition, one of the purposes of one embodiment of the present invention is to provide a transistor, a semiconductor device or a display device with high reliability. In addition, one of the purposes of one embodiment of the present invention is to provide a display device that is easy to achieve high definition. In addition, one of the purposes of one embodiment of the present invention is to provide a method for manufacturing a semiconductor device or a display device with high productivity. In addition, one of the purposes of one embodiment of the present invention is to provide a novel transistor, a semiconductor device, a display device and a method for manufacturing them.

[0010] Note that the description of these objects does not prevent the existence of other objects. One embodiment of the present invention does not need to achieve all of the above objects. Note that objects other than the above objects can be extracted from the description of the specification, drawings, and claims. Solutions to technical problems

[0011] One embodiment of the present invention is a semiconductor device, which includes a semiconductor layer, a first conductive layer, a second conductive layer, a third conductive layer, a fourth conductive layer, a first insulating layer and a second insulating layer, at least a portion of the second conductive layer is in contact with the top surface of the first conductive layer, the first insulating layer is located on the second conductive layer, the third conductive layer is located on the first insulating layer, the semiconductor layer is in contact with the top surface of the first conductive layer, the side surface of the second conductive layer, the third conductive layer and the side surface of the first insulating layer, the second insulating layer is located on the semiconductor layer, and the fourth conductive layer is located on the second insulating layer and overlaps with the semiconductor layer via the second insulating layer.

[0012] In addition, one embodiment of the present invention is a semiconductor device, which includes a semiconductor layer, a first conductive layer, a second conductive layer, a third conductive layer, a fourth conductive layer, a first insulating layer and a second insulating layer, the second conductive layer contacts the top surface of the first conductive layer and has a first opening reaching the first conductive layer, the first insulating layer is located on the second conductive layer and has a second opening overlapping with the first opening, the third conductive layer is located on the first insulating layer and has a third opening overlapping with the first opening and the second opening, the semiconductor layer contacts the top surface of the first conductive layer through the first opening to the third opening and contacts the side surface of the second conductive layer in the first opening, the third conductive layer and the side surface of the first insulating layer in the second opening, the second insulating layer is located on the semiconductor layer, and the fourth conductive layer is located on the second insulating layer and overlaps with the semiconductor layer via the second insulating layer.

[0013] The shortest distance from the top surface of the first conductive layer to the top surface of the second conductive layer is preferably longer than the shortest distance from the top surface of the first conductive layer to the bottom surface of the fourth conductive layer.

[0014] The conductivity of the second conductive layer is preferably higher than the conductivity of the first conductive layer.

[0015] The semiconductor layer is preferably in contact with the top surface and the side surfaces of the third conductive layer.

[0016] The semiconductor layer preferably contains a metal oxide.

[0017] In addition, a metal oxide containing the metal contained in the second conductive layer may be included between the semiconductor layer and the second conductive layer.

[0018] In addition, one embodiment of the present invention is a semiconductor device, which includes a first metal oxide layer, a second metal oxide layer, a first conductive layer, a second conductive layer, a third conductive layer, a fourth conductive layer, a first insulating layer and a second insulating layer, at least a portion of the second conductive layer is in contact with the top surface of the first conductive layer, the first insulating layer is located on the second conductive layer, the third conductive layer is located on the first insulating layer, the first metal oxide layer is in contact with the top surface of the first conductive layer, the side surface of the second metal oxide layer, the third conductive layer and the side surface of the first insulating layer, the second metal oxide layer is in contact with the side surface of the second conductive layer, the second insulating layer is located on the first metal oxide layer, the fourth conductive layer is located on the second insulating layer and overlaps with the first metal oxide layer via the second insulating layer, and the second metal oxide and the second conductive layer contain the same metal element. Effects of the Invention

[0019] According to one embodiment of the present invention, a micro transistor can be provided. In addition, according to one embodiment of the present invention, a transistor with a small channel length can be provided. In addition, according to one embodiment of the present invention, a transistor with a large on-state current can be provided. In addition, according to one embodiment of the present invention, a transistor with good electrical characteristics can be provided. In addition, according to one embodiment of the present invention, a semiconductor device with a small footprint can be provided. In addition, according to one embodiment of the present invention, a semiconductor device with low wiring resistance can be provided. In addition, according to one embodiment of the present invention, a semiconductor device or a display device with low power consumption can be provided. In addition, according to one embodiment of the present invention, a transistor, a semiconductor device or a display device with high reliability can be provided. In addition, according to one embodiment of the present invention, a display device that can easily achieve high definition can be provided. In addition, according to one embodiment of the present invention, a method for manufacturing a semiconductor device or a display device with high productivity can be provided. In addition, according to one embodiment of the present invention, a novel transistor, a semiconductor device, a display device and a method for manufacturing them can be provided.

[0020] Note that the description of these effects does not prevent the existence of other effects. One embodiment of the present invention does not necessarily have all of the above effects. Effects other than the above effects can be extracted from the description of the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A is a plan view showing an example of a semiconductor device. Figure 1B and Figure 1C is a cross-sectional view showing an example of a semiconductor device. Figure 2A is a plan view showing an example of a semiconductor device. Figure 2B is a cross-sectional view showing an example of a semiconductor device. FIG. 3A to FIG. 3C is a cross-sectional view showing an example of a semiconductor device. Figure 4A is a plan view showing an example of a semiconductor device. Figure 4B and Figure 4C is a cross-sectional view showing an example of a semiconductor device. Figure 5A is a plan view showing an example of a semiconductor device. Figure 5B and Figure 5C is a cross-sectional view showing an example of a semiconductor device. Fig. 6A is a plan view showing an example of a semiconductor device. Figure 6B and Figure 6C is a cross-sectional view showing an example of a semiconductor device. Fig. 7Ais a plan view showing an example of a semiconductor device. Figure 7B and Figure 7C is a cross-sectional view showing an example of a semiconductor device. Fig. 8A is a plan view showing an example of a semiconductor device. Figure 8B and Figure 8C is a cross-sectional view showing an example of a semiconductor device. Fig. 9A and Fig. 9B is a cross-sectional view showing an example of a semiconductor device. FIG. 10A to FIG. 10I is a circuit diagram showing an example of a semiconductor device. FIG. 11A to FIG. 11C is a cross-sectional view showing an example of a semiconductor device. Fig. 12A is a plan view showing an example of a semiconductor device. Fig. 12B is a cross-sectional view showing an example of a semiconductor device. Fig.13A and Fig. 13B is a cross-sectional view showing an example of a semiconductor device. Fig.14A is a plan view showing an example of a semiconductor device. Fig. 14B and Fig. 14C is a cross-sectional view showing an example of a semiconductor device. Fig.15A is a plan view showing an example of a semiconductor device. Fig. 15B is a cross-sectional view showing an example of a semiconductor device. Fig.16A is a plan view showing an example of a semiconductor device. Fig. 16B is a cross-sectional view showing an example of a semiconductor device. FIG. 17A to FIG. 17D is a cross-sectional view showing an example of a method for manufacturing a semiconductor device. 18A to 18C is a cross-sectional view showing an example of a method for manufacturing a semiconductor device. FIG. 19A to FIG. 19C is a cross-sectional view showing an example of a method for manufacturing a semiconductor device. Fig. 20 It is a perspective view showing an example of a display device. Fig.21A and Fig.21B is a cross-sectional view showing an example of a display device. Fig. 22 is a cross-sectional view showing an example of a display device. FIG. 23A to FIG. 23Cis a cross-sectional view showing an example of a display device. Fig.24A and Fig. 24B is a cross-sectional view showing an example of a display device. Fig.25 is a cross-sectional view showing an example of a display device. Fig.26 is a cross-sectional view showing an example of a display device. Fig. 27 is a cross-sectional view showing an example of a display device. Fig.28A and Fig.28B is a cross-sectional view showing an example of a display device. FIG. 29A to FIG. 29F This is a cross-sectional view showing an example of a method for manufacturing a display device. FIG. 30A to FIG. 30D is a diagram showing an example of an electronic device. FIG. 31A to FIG. 31F is a diagram showing an example of an electronic device. FIG. 32A to FIG. 32G is a diagram showing an example of an electronic device. Modes for Carrying Out the Invention

[0022] The embodiments are described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and a person skilled in the art can easily understand that the mode and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents described in the embodiments shown below.

[0023] Note that in the invention structure described below, the same symbols are used to represent the same parts or parts with the same function in different drawings, and repeated description is omitted. In addition, when representing parts with the same function, the same hatching is sometimes used without special additional symbols.

[0024] In addition, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent its actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0025] Note that in this specification, etc., ordinal numbers such as "first" and "second" are added for convenience, but they do not limit the number of components or the order of components (for example, the order of processes or the order of stacking). In addition, the ordinal numbers added to components in one part of this specification may not be consistent with the ordinal numbers added to the components in other parts of this specification or claims.

[0026] In addition, depending on the situation or state, the "film" and the "layer" may be interchanged. For example, the "conductive layer" may be replaced with the "conductive film". In addition, the "insulating film" may be replaced with the "insulating layer".

[0027] A transistor is a type of semiconductor element and can realize functions of amplifying current or voltage, controlling switching operations of conduction or non-conduction, etc. The transistor in this specification includes IGFET (Insulated Gate Field Effect Transistor) and thin film transistor (TFT: Thin Film Transistor).

[0028] In addition, the functions of "source" and "drain" may be interchanged when transistors with different polarities are used or when the current direction of the circuit operation changes. Therefore, in this specification, "source" and "drain" may be interchanged.

[0029] In this specification, "electrical connection" includes connection through "an element having some kind of electrical function". Here, "an element having some kind of electrical function" is not particularly limited as long as it can transmit and receive electrical signals between the connected objects. For example, "an element having some kind of electrical function" includes switching elements such as transistors, resistors, coils, capacitors, and other elements having various functions in addition to electrodes and wiring.

[0030] In this specification, unless otherwise specified, off-state current refers to the leakage current between the source and the drain when the transistor is in the off state (also called non-conducting state or blocking state). In an n-channel transistor, the off state refers to the voltage V between the gate and the source. gs Below the threshold voltage V th (In a p-channel transistor, V gs Higher than V th ) status.

[0031] In this specification, etc., "the top surface shapes are roughly consistent" means that at least a portion of the edges of each layer in the stack overlap. For example, it includes the case where the upper layer and the lower layer are processed by the same mask pattern or a portion of the same mask pattern. However, in reality, sometimes the edges do not overlap, so that the upper layer is located inside the lower layer or the upper layer is located outside the lower layer. In this case, it can also be said that "the top surface shapes are roughly consistent". When the top surface shapes are consistent or roughly consistent, it can also be said that the ends are aligned or roughly aligned.

[0032] In this specification, etc., a tapered shape refers to a shape in which at least a portion of the side surface of a constituent element is inclined relative to the substrate surface or the formed surface. For example, it is preferred to have a region in which the angle formed by the inclined side surface and the substrate surface or the formed surface (also referred to as a tapered angle) is greater than 0° and less than 90°. Here, the side surface, substrate surface, and formed surface of the constituent element do not necessarily have to be completely flat, and may also be approximately planar with a slight curvature or approximately planar with fine concave-convex shapes.

[0033] Note that in this specification and the like, an oxynitride refers to a material containing more oxygen than nitrogen in its composition, and an oxynitride refers to a material containing more nitrogen than oxygen in its composition.

[0034] For example, the content of elements such as hydrogen, oxygen, and nitrogen can be analyzed using secondary ion mass spectrometry (SIMS) or X-ray photoelectron spectroscopy (XPS). XPS is suitable when the content of the target element is high (for example, 0.5 atomic% or more or 1 atomic%). On the other hand, SIMS is suitable when the content of the target element is low (for example, 0.5 atomic% or less or 1 atomic%). When comparing the content of elements, it is more preferable to use a composite analysis using both SIMS and XPS analysis techniques.

[0035] In this specification and the like, when it is described that A is in contact with B, at least a portion of A is in contact with B. Therefore, for example, it can be alternatively described that A has a region in contact with B.

[0036] In this specification and the like, when it is described that A is located on B, at least a portion of A is located on B. Therefore, for example, it can be alternatively described that A has a region located on B.

[0037] In this specification and the like, when it is described that A and B overlap, at least a portion of A overlaps with B. Therefore, for example, it can be alternatively described that A has a region that overlaps with B.

[0038] In this specification, etc., a device manufactured using a metal mask or FMM (Fine Metal Mask) is sometimes referred to as a device having an MM (Metal Mask) structure. In addition, in this specification, etc., a device manufactured without using a metal mask or FMM is sometimes referred to as a device having an MML (Metal Mask Less) structure.

[0039] In this specification, etc., a structure in which light-emitting layers are separately manufactured between light-emitting elements (also called light-emitting devices) with different emission wavelengths is sometimes referred to as an SBS (SideBySide) structure. Since the SBS structure can optimize the materials and structures of each light-emitting element, the freedom of choice of materials and structures is increased, and it is easy to achieve improved brightness and reliability.

[0040] In this specification, holes or electrons are sometimes referred to as "carriers". Specifically, a hole injection layer or an electron injection layer is sometimes referred to as a "carrier injection layer", a hole transport layer or an electron transport layer is sometimes referred to as a "carrier transport layer", and a hole blocking layer or an electron blocking layer is sometimes referred to as a "carrier blocking layer". Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier blocking layer are sometimes not clearly distinguishable. In addition, sometimes one layer has the functions of two or three of a carrier injection layer, a carrier transport layer, and a carrier blocking layer.

[0041] In this specification, etc., a light-emitting element includes an EL layer between a pair of electrodes. The EL layer includes at least a light-emitting layer. Here, as the layer included in the EL layer (also referred to as a functional layer), a light-emitting layer, a carrier injection layer (hole injection layer and electron injection layer), a carrier transport layer (hole transport layer and electron transport layer) and a carrier blocking layer (hole blocking layer and electron blocking layer) can be cited. In this specification, etc., a light-receiving element (also referred to as a light-receiving device) includes at least an active layer used as a photoelectric conversion layer between a pair of electrodes. In this specification, etc., one of a pair of electrodes is sometimes referred to as a pixel electrode, and the other is referred to as a common electrode.

[0042] In this specification, etc., a sacrificial layer (also referred to as a mask layer) is located at least above the light-emitting layer (more specifically, a layer processed into an island shape among the layers constituting the EL layer) and has a function of protecting the light-emitting layer during the manufacturing process.

[0043] In this specification and the like, disconnection refers to a phenomenon in which a layer, a film, or an electrode is disconnected due to the shape of a formed surface (for example, a step, etc.).

[0044] (Implementation Method 1) In this embodiment, a semiconductor device which is one embodiment of the present invention is described with reference to FIGS. 1 to 16 .

[0045] One embodiment of the present invention includes a semiconductor layer, a first conductive layer, a second conductive layer, a third conductive layer, a fourth conductive layer, a first insulating layer, and a second insulating layer.

[0046] The first conductive layer is used as one of a source electrode and a drain electrode of the transistor.

[0047] The second conductive layer is located on the first conductive layer. At least a portion of the second conductive layer is in contact with the top surface of the first conductive layer. The conductivity of the second conductive layer is preferably higher than that of the first conductive layer. The second conductive layer is preferably used as an auxiliary wiring of the first conductive layer. The second conductive layer may also include a first opening (also referred to as a first opening portion) that reaches the first conductive layer. Note that in this specification, etc., the opening may be referred to as an opening portion.

[0048] The first insulating layer is located on the second conductive layer. The first insulating layer may also include a second opening overlapping the first opening.

[0049] The third conductive layer is located on the first insulating layer. The third conductive layer is used as the other of the source electrode and the drain electrode of the transistor. In addition, for example, the third conductive layer includes a third opening overlapping the first opening and the second opening.

[0050] The semiconductor layer is in contact with the top surface of the first conductive layer, the side surface of the first insulating layer and the third conductive layer. In addition, the semiconductor layer is preferably in contact with the side surface of the second conductive layer. In addition, the semiconductor layer may also be in contact with an oxide containing the same metal as the metal contained in the second conductive layer. The oxide is sometimes formed between the semiconductor layer and the second conductive layer. In the case where the above-mentioned first to third openings are provided, the semiconductor layer is in contact with the top surface of the first conductive layer through the first to third openings, and is in contact with the side surface of the second conductive layer in the first opening, the third conductive layer and the side surface of the first insulating layer in the second opening. The semiconductor layer preferably contains a metal oxide.

[0051] The second insulating layer is located on the semiconductor layer and is used as a gate insulating layer.

[0052] The fourth conductive layer is located on the second insulating layer and overlaps with the semiconductor layer via the second insulating layer. The fourth conductive layer is used as a gate electrode of the transistor. When the first to third openings are provided, the fourth conductive layer overlaps with the semiconductor layer via the second insulating layer at a position overlapping with the first opening, the second opening, and the third opening.

[0053] The first insulating layer has a portion in contact with a channel formation region in the semiconductor layer. The channel formation region is a high resistance region with a low carrier concentration. It can be said that the channel formation region is i-type (intrinsic) or substantially i-type. When the first insulating layer includes a layer containing a large amount of oxygen, an i-type region is easily formed in a region in contact with the first insulating layer in the semiconductor layer and in the vicinity thereof.

[0054] The second conductive layer is in contact with a region (also referred to as a bias region) in the semiconductor layer to which a gate electric field is not easily applied. When the resistance of the bias region is high, the field effect mobility of the transistor sometimes decreases. By arranging the second conductive layer and the semiconductor layer in contact with each other, the resistance of the region in contact with the second conductive layer and its vicinity in the semiconductor layer can be reduced. Thus, the decrease in field effect mobility caused by the bias region can be suppressed.

[0055] Specifically, when the second conductive layer is in contact with the semiconductor layer, during heat treatment, the second conductive layer extracts oxygen contained in the semiconductor layer, thereby easily forming oxygen vacancies in the semiconductor layer. When impurities such as hydrogen enter the oxygen vacancies, the impurities are used as donors and easily increase the carrier concentration. Therefore, the resistance of the region in the semiconductor layer that contacts the second conductive layer and its vicinity can be reduced.

[0056] Furthermore, grooves (slits) may be provided instead of the first opening, the second opening, and the third opening.

[0057] [Transistor 100] Figure 1A and Figure 2A A top view of transistor 100 is shown. Figure 2A and Figure 1A The difference is: Figure 2A The diameter D143 and the channel width W100 are shown without showing the dot-dash line B1-B2. Figure 1A and Figure 2A Note that some components are also omitted in other top views.

[0058] Figure 1B and Figure 2B It is along Figure 1A and Figure 2A A cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 2B It can also be said that Figure 1B Magnified image of . Figure 1B The openings 141, 143, 148 and the shortest distances T1, T2 are shown. Figure 2B The diameter D143, the channel width W100, the channel length L100, the region 108n, the thickness T110 and the angle θ110 are shown in FIG. Figure 1B and Figure 2B Common between. Figure 1C It is along Figure 1A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0059] The transistor 100 is provided on the substrate 102. The transistor 100 includes a conductive layer 112a, a conductive layer 103, an insulating layer 110 (insulating layers 110a, 110b, 110c), a semiconductor layer 108, a conductive layer 112b, an insulating layer 106, and a conductive layer 104. Each layer constituting the transistor 100 may have a single-layer structure or a stacked-layer structure. Note that the conductive layer 103 and the insulating layer 110 may not be included in the components of the transistor 100. In other words, it can be said that the semiconductor device of one embodiment of the present invention includes the transistor 100, the conductive layer 103, and the insulating layer 110.

[0060] The conductive layer 112a is provided over the substrate 102. The conductive layer 112a is used as one of a source electrode and a drain electrode of the transistor 100.

[0061] Notice, Figure 1C Although the example in which the side surface of the conductive layer 112a is not covered by the conductive layer 103 is shown, the present invention is not limited thereto. A part or all of the side surface of the conductive layer 112a may be covered by the conductive layer 103. For example, a part of the conductive layer 112a may be in contact with the substrate 102.

[0062] Conductive layer 103 is located on conductive layer 112a. At least a portion of conductive layer 103 is in contact with the top surface of conductive layer 112a. Conductive layer 103 can be used as an auxiliary wiring of conductive layer 112a. In addition, conductive layer 103 can also be used as wiring. Opening 148 that reaches conductive layer 112a is provided in conductive layer 103.

[0063] The insulating layer 110 is disposed on the substrate 102, the conductive layer 112a, and the conductive layer 103. The insulating layer 110 is provided with an opening 141 overlapping with the opening 148.

[0064] The insulating layer 110 has a stacked structure of an insulating layer 110 a , an insulating layer 110 b on the insulating layer 110 a , and an insulating layer 110 c on the insulating layer 110 b .

[0065] The conductive layer 112b is located on the insulating layer 110. The conductive layer 112b is provided with an opening 143 overlapping with the openings 141 and 148. The conductive layer 112b is used as the other of the source electrode and the drain electrode of the transistor.

[0066] The semiconductor layer 108 is in contact with the top surface of the conductive layer 112a, the side surface of the insulating layer 110, and the top surface and side surface of the conductive layer 112b. The semiconductor layer 108 is provided in a manner in contact with the end portion on the side of the opening 141 in the insulating layer 110 (which may also be referred to as the side wall of the opening 141) and the end portion on the side of the opening 143 in the conductive layer 112b (which may also be referred to as the side wall of the opening 143). In addition, the semiconductor layer 108 is preferably in contact with the side surface of the conductive layer 103. The semiconductor layer 108 is preferably provided in a manner in contact with the end portion on the side of the opening 148 of the conductive layer 103 (which may also be referred to as the side wall of the opening 148). The semiconductor layer 108 is in contact with the conductive layer 112a through the opening 141, the opening 143, and the opening 148.

[0067] In addition, if Figure 3A As shown, sometimes the metal oxide 103s is formed between the conductive layer 103 and the semiconductor layer 108. For example, the metal contained in the conductive layer 103 is oxidized by the oxygen contained in the semiconductor layer 108 to form the metal oxide 103s. In other words, it can be said that the metal contained in the metal oxide 103s is the same as the metal contained in the conductive layer 103. Since the conductive layer 103 and the semiconductor layer 108 may not be electrically connected, the metal oxide 103s may be formed on a part or the whole of the side wall of the opening 148. In addition, the conductive layer 103 and the semiconductor layer 108 may not have a portion that contacts each other. For example, the presence of the metal oxide 103s can be confirmed using energy dispersive X-ray spectroscopy (EDX: Energy Dispersive X-ray Spectrometry).

[0068] In the semiconductor layer 108, a region in contact with the conductive layer 112a is used as one of the source region and the drain region, and a region in contact with the conductive layer 112b is used as the other of the source region and the drain region. In addition, in the semiconductor layer 108, a region in contact with the conductive layer 103 (or the metal oxide 103s) is used as a low resistance region (also referred to as n + Type area, n + In the semiconductor layer 108, the region in contact with the insulating layer 110a is preferably higher in resistance than the region in contact with the conductive layer 103 and lower in resistance than the region in contact with the insulating layer 110b. In the semiconductor layer 108, the region in contact with the insulating layer 110a may be n - Type area or n - area.

[0069] Figure 1BAn example is shown in which the end of the semiconductor layer 108 is in contact with the top surface of the conductive layer 112b. That is, the transistor of one embodiment of the present invention is preferably a bottom contact type transistor. Thus, the semiconductor layer 108 can be deposited after the conductive layer 112b is manufactured (for example, after the film to be the conductive layer 112b is processed or after the opening 143 is formed), so damage to the semiconductor layer 108 can be suppressed. In addition, the process of forming the opening 143 and the process of forming the opening 141 can be performed continuously (without including the deposition process, etc.), so it is preferred. Note that the transistor of one embodiment of the present invention may also be a top contact type transistor. Specifically, the end of the semiconductor layer 108 may also be covered by the conductive layer 112b and in contact with the insulating layer 110 (refer to the transistor 100E (described later) Figure 8B wait)).

[0070] The insulating layer 106 is disposed on the insulating layer 110, the semiconductor layer 108, and the conductive layer 112b. The insulating layer 106 is disposed along the sidewalls of the opening 148, the sidewalls of the opening 141, and the sidewalls of the opening 143 via the semiconductor layer 108. The insulating layer 106 serves as a gate insulating layer.

[0071] The conductive layer 104 is located over the insulating layer 106. The conductive layer 104 overlaps with the semiconductor layer 108 via the insulating layer 106 at a position overlapping with the opening 148, the opening 141, and the opening 143. The conductive layer 104 functions as a gate electrode of the transistor.

[0072] The semiconductor layer 108 has a region (bias region) that is farther from the gate than the channel formation region and to which the gate electric field is not easily applied. Specifically, there is a portion of the semiconductor layer 108 located below the bottom surface of the conductive layer 104 (on the conductive layer 112a side) inside the openings 141 and 148, and this portion is a region to which the gate electric field is not easily applied because the distance between the portion and the conductive layer 104 is greater than the thickness of the insulating layer 106. The conductive layer 103 is preferably provided in contact with the bias region.

[0073] When the resistance of the bias region is high, the field effect mobility of the transistor 100 may decrease. By providing the conductive layer 103 and the semiconductor layer 108 in contact with each other, the resistance of the region in contact with the conductive layer 103 and its vicinity in the semiconductor layer 108 can be reduced (see Figure 2B Thereby, the decrease in field effect mobility caused by the offset region can be suppressed.

[0074] When the conductive layer 103 is in contact with the semiconductor layer 108, the conductive layer 103 extracts oxygen contained in the semiconductor layer 108 due to the heat applied in the manufacturing process of the transistor 100, thereby easily forming oxygen vacancies in the semiconductor layer 108. When impurities such as hydrogen enter the oxygen vacancies, the impurities are used as donors and the carrier concentration is easily increased. Therefore, the region in the semiconductor layer 108 that is in contact with the conductive layer 103 and its vicinity can be made into a low resistance region.

[0075] In the semiconductor layer 108 of the transistor 100, a region in contact with the conductive layer 103 as a low resistance region is provided between a region in contact with the conductive layer 112a and a region in contact with the insulating layer 110c as an i-type region. Here, when the conductive layer 112a is used as a drain electrode and the conductive layer 112b is used as a source electrode, it can also be said that the semiconductor layer 108 includes a low resistance region between the region in contact with the drain electrode and the channel formation region. As a result, a high electric field is less likely to be generated near the drain region, and generation of hot carriers can be suppressed, thereby suppressing transistor degradation.

[0076] like Figure 1B As shown in FIG. 1 , the shortest distance T1 from the top surface of the conductive layer 112a to the portion of the semiconductor layer 108 in contact with the insulating layer 110b is longer than the shortest distance T2 from the top surface of the conductive layer 112a to the bottom surface of the conductive layer 104. In addition, it can be said that when viewed from a cross-section, the bottom surface of the conductive layer 104 located inside the opening is located further to the lower side (toward the substrate 102) than the portion of the insulating layer 110b in contact with the semiconductor layer 108. Thus, a gate electric field can be reliably applied to the channel formation region of the semiconductor layer 108, and the electrical characteristics of the transistor can be improved.

[0077] It can be said that the shortest distance T1 is determined by the sum of the thickness of the conductive layer 103 and the thickness of the insulating layer 110a, and the shortest distance T2 is determined by the sum of the thickness of the semiconductor layer 108 and the thickness of the insulating layer 106. Therefore, it can be said that the sum of the thickness of the conductive layer 103 and the thickness of the insulating layer 110a is preferably greater than the sum of the thickness of the semiconductor layer 108 and the thickness of the insulating layer 106. The shortest distance T1 is preferably 0.5 times or more of the shortest distance T2, more preferably 1.0 times or more, and further preferably more than 1.0 times.

[0078] The transistor 100 includes a semiconductor layer 108 in contact with the conductive layer 103 and the insulating layer 110, and a channel formation region in the semiconductor layer 108 is arranged at a position where a gate electric field is sufficiently applied. In addition, the resistance of the bias region in the semiconductor layer 108 is reduced. Therefore, a decrease in the field effect mobility of the transistor 100 can be suppressed and good electrical characteristics can be obtained.

[0079] In a transistor of one embodiment of the present invention, the source electrode and the drain electrode are located at different heights, so the current flowing through the semiconductor layer flows from top to bottom or from bottom to top. In other words, it can be said that the channel length direction has a component in the height direction (vertical direction), so the transistor of one embodiment of the present invention can be called a vertical transistor, a vertical channel transistor, a vertical channel type transistor, etc.

[0080] Since the source electrode, the semiconductor layer, and the drain electrode can be overlapped, the occupied area of ​​the transistor of one embodiment of the present invention can be made much smaller than that of a so-called planar transistor in which the semiconductor layer is arranged in a planar shape.

[0081] The conductive layer 112a, the conductive layer 112b, the conductive layer 103, and the conductive layer 104 can all be used as wirings, and the transistor 100 can be provided in a region where these wirings overlap. That is, in a circuit including the transistor 100 and the wirings, the occupied area of ​​the transistor 100 and the wirings can be reduced. Therefore, the occupied area of ​​the circuit can be reduced to realize a small semiconductor device.

[0082] For example, when a semiconductor device according to one embodiment of the present invention is used in a pixel circuit of a display device, the area occupied by the pixel circuit can be reduced, and a high-definition display device can be realized. In addition, for example, when a semiconductor device according to one embodiment of the present invention is used in a drive circuit (for example, one or both of a gate line drive circuit and a source line drive circuit) of a display device, the area occupied by the drive circuit can be reduced, so a display device with a narrow frame can be realized.

[0083] There is no limitation on the top surface shape of the opening 141, the opening 143 and the opening 148, for example, they may be round, oval, triangular, quadrilateral (including rectangle, rhombus, square), pentagonal, star-shaped polygon or other polygons, or the corners of these polygons may be rounded. The polygon may also be a concave polygon (a polygon with at least one internal angle exceeding 180 degrees) or a convex polygon (a polygon with internal angles less than 180 degrees). Figure 1A As shown in the drawings, the top surface shapes of the openings 141, 143, and 148 are preferably circular. By making the top surface shape of the openings circular, the processing accuracy when forming the openings can be improved, and a fine opening can be formed. Note that in this specification, etc., a circle is not limited to a perfect circle. In this specification, etc., the top surface shape refers to the shape when viewed from a plane.

[0084] In this specification, etc., the top surface shape of the opening 141 refers to the shape of the top surface end of the insulating layer 110 on the side of the opening 141. In addition, the top surface shape of the opening 143 refers to the shape of the bottom surface end of the conductive layer 112b on the side of the opening 143. In addition, the top surface shape of the opening 148 refers to the shape of the top surface end or the bottom surface end of the conductive layer 103 on the side of the opening 148.

[0085] like Figure 1A As shown in FIG. 1 and FIG. 2 , the top surface shape of the opening 141 and the top surface shape of the opening 143 can be made consistent or substantially consistent. Figure 1B and Figure 1C As shown in FIG. 1 , the bottom surface end of the conductive layer 112b on the side of the opening 143 is preferably consistent or substantially consistent with the top surface end of the insulating layer 110 on the side of the opening 141. The bottom surface of the conductive layer 112b refers to the surface on the side of the insulating layer 110. The top surface of the insulating layer 110 refers to the surface on the side of the conductive layer 112b.

[0086] In addition, the top surface shape of the opening 141 and the top surface shape of the opening 143 may not be consistent with each other (refer to the transistor 100C described later). Fig. 6A In addition, when the top surfaces of the openings 141 and 143 are circular, the openings 141 and 143 may be concentric circles or non-concentric circles.

[0087] In addition, if Figure 1A As shown in FIG. 1 and FIG. 2 , the top surface shape of the opening 141 can be made consistent or substantially consistent with the top surface shape of the opening 148. Figure 1B and Figure 1C As shown in FIG. 1 , the top end of the opening 148 of the conductive layer 103 is preferably aligned or substantially aligned with the bottom end of the opening 141 of the insulating layer 110. The bottom surface of the conductive layer 103 refers to the surface of the insulating layer 110. The bottom surface of the insulating layer 110 refers to the surface of the conductive layer 103.

[0088] Furthermore, the top surface shape of the opening 141 and the top surface shape of the opening 148 may not be consistent with each other.

[0089] Figure 3B The example in which the opening 148 is wider than the opening 141 is shown. For example, even when the opening 141 and the opening 148 are formed using the same resist mask, a portion of the conductive layer 103 under the end of the insulating layer 110 may disappear due to side etching. In addition, in order to form the semiconductor layer 108 with high coverage along the side wall of the opening, the semiconductor layer 108 is preferably deposited by the ALD method.

[0090] also, Figure 3C The example in which the opening 148 is narrower than the opening 141 is shown. For example, the opening 148 may be provided in the conductive layer 103 before a film to be the insulating layer 110a is deposited. Alternatively, the opening 141 and the opening 148 may be formed using different resist masks.

[0091] and Figure 1B Compared with the structure shown in Figure 3B and Figure 3CIn the structure shown, the area of ​​the semiconductor layer 108 in contact with the conductive layer 103 is larger, so that the low resistance area can be expanded.

[0092] Reference Figure 2A and Figure 2B The channel length, channel width, etc. of the transistor 100 will be described.

[0093] Figure 2B The dotted double arrow in FIG. 1 indicates a channel length L100 of the transistor 100. The channel length L100 can be considered to be the shortest distance between a portion of the semiconductor layer 108 in contact with the insulating layer 110a and a portion in contact with the insulating layer 110c when viewed in cross section.

[0094] The channel length L100 of the transistor 100 is equivalent to the length of the side surface of the opening 141 side of the insulating layer 110b when viewed from a cross section. That is, the channel length L100 is determined by the thickness T110 of the insulating layer 110b and the angle θ110 formed by the side surface of the opening 141 side of the insulating layer 110b and the formed surface of the insulating layer 110b (here, the top surface of the insulating layer 110a). Therefore, for example, the channel length L100 can be set to a value smaller than the limiting resolution of the exposure device, and a micro transistor can be realized. Specifically, a transistor with an extremely small channel length that cannot be realized by the exposure device used in the mass production of conventional flat panel displays (for example, a minimum line width of about 2μm or 1.5μm) can be realized. In addition, a transistor with a channel length of less than 10nm can be realized without using a very expensive exposure device used in the most advanced LSI technology.

[0095] The channel length L100 may be, for example, 5 nm or more, 7 nm or more, or 10 nm or more and less than 3 μm, or 2.5 μm or less, 2 μm or less, 1.5 μm or less, 1.2 μm or less, 1 μm or less, 500 nm or less, 300 nm or less, 200 nm or less, 100 nm or less, 50 nm or less, 30 nm or less, or 20 nm or less. For example, the channel length L100 may be set to be 100 nm or more and 1 μm or less.

[0096] By reducing the channel length L100, the on-state current of the transistor 100 can be increased. By using the transistor 100, a circuit capable of high-speed operation can be manufactured. Furthermore, the area occupied by the circuit can be reduced. Therefore, a small semiconductor device can be realized. For example, when a semiconductor device of one embodiment of the present invention is used in a large display device or a high-definition display device, the signal delay of each wiring can be reduced when the number of wirings increases, thereby suppressing display unevenness. In addition, since the area occupied by the circuit can be reduced, the frame of the display device can be reduced.

[0097] By adjusting the thickness T110 and the angle θ110 of the insulating layer 110b, the channel length L100 can be controlled. Figure 2B In FIG. 1 , a double-pointed arrow indicates a thickness T110 of the insulating layer 110 b .

[0098] The thickness T110 of the insulating layer 110b can be, for example, greater than 10 nm, greater than 50 nm, greater than 100 nm, greater than 150 nm, greater than 200 nm, greater than 300 nm, greater than 400 nm or greater than 500 nm and less than 3.0 μm, less than 2.5 μm, less than 2.0 μm, less than 1.5 μm, less than 1.2 μm or less than 1.0 μm.

[0099] The side surface of the opening 141 of the insulating layer 110b preferably has a tapered shape. The angle θ110 formed by the side surface of the opening 141 of the insulating layer 110b and the formed surface of the insulating layer 110b (here, the top surface of the insulating layer 110a) is preferably 90 degrees or less. By reducing the angle θ110, the coverage of the layer (for example, the semiconductor layer 108) provided on the insulating layer 110b can be improved. In addition, the smaller the angle θ110 is, the larger the channel length L100 can be, and the larger the angle θ110 is, the smaller the channel length L100 can be.

[0100] The angle θ110 may be, for example, greater than 30 degrees, greater than 35 degrees, greater than 40 degrees, greater than 45 degrees, greater than 50 degrees, greater than 55 degrees, greater than 60 degrees, greater than 65 degrees, or greater than 70 degrees and less than 90 degrees, less than 85 degrees, or less than 80 degrees. In addition, the angle θ110 may be less than 75 degrees, less than 70 degrees, less than 65 degrees, or less than 60 degrees.

[0101] When the angle θ110 is greater than or equal to 80 degrees and less than or equal to 90 degrees, it is preferable to form a film covering the insulating layer 110 by a deposition method having high coverage. For example, it is preferable to form the conductive layer 104 by a CVD method, and to form the insulating layer 106 and the semiconductor layer 108 by an ALD method. In addition, it is preferable to form the conductive layer 104, the insulating layer 106, and the semiconductor layer 108 by, for example, an ALD method. In addition, when the above-mentioned angle θ110 is greater than or equal to 60 degrees and less than or equal to 85 degrees, it is also possible to form a film covering the insulating layer 110 by a deposition method having higher productivity. For example, it is preferable to form the semiconductor layer 108 by a sputtering method.

[0102] Note that, here, the angle θ110 is set based on the insulating layer 110b, but may be set based on the entire insulating layer 110. In other words, the angle θ110 may be an angle formed by the side surface of the opening 141 of the insulating layer 110 and the formed surface of the insulating layer 110 (here, the top surface of the conductive layer 103).

[0103] In addition, when the channel formation region includes a region in contact with the insulating layer 110a and a region in contact with the insulating layer 110c in the semiconductor layer 108, the channel length L100 can be said to be the shortest distance between a portion in contact with the conductive layer 103 and a portion in contact with the conductive layer 112b in the semiconductor layer 108 when viewed from a cross section. In addition, the channel length L100 is equivalent to the length of the side surface of the opening 141 side of the entire insulating layer 110 when viewed from a cross section.

[0104] exist Figure 2A and Figure 2B In FIG. 1 , a double arrow with a double-dashed line indicates a diameter D143 of the opening 143 . Figure 2A An example is shown in which the top surface shape of the opening 141, the opening 143, and the opening 148 is a circle with a diameter D143. In this case, the channel width W of the transistor 100 is consistent with the circumference of the circle. In other words, the channel width W is π×D143. In this way, when the top surface shape of the opening 141, the opening 143, and the opening 148 is circular, a transistor with a smaller channel width W can be realized compared to using other shapes.

[0105] Note that the diameter of the opening 141 and the diameter of the opening 143 are sometimes different, and the diameter of the opening 141 and the diameter of the opening 148 are also sometimes different. In addition, the diameter of the opening 148, the diameter of the opening 141, and the diameter of the opening 143 sometimes change in the depth direction. When the opening 141, the opening 143, and the opening 148 are regarded as one opening, as the diameter of the opening, for example, the average value of the diameter of the highest position, the diameter of the lowest position, and the diameter of the position of the midpoint of the insulating layer 110 (or the insulating layer 110b) when viewed from a cross section can be used. Alternatively, as the diameter of the opening, for example, any of the diameter of the highest position, the diameter of the lowest position, and the diameter of the position of the midpoint of the insulating layer 110 (or the insulating layer 110b) when viewed from a cross section can be used.

[0106] When the opening 143 is formed by photolithography, the diameter D143 of the opening 143 is equal to or larger than the limiting resolution of the exposure device. The diameter D143 may be, for example, equal to or larger than 20 nm, equal to or larger than 50 nm, equal to or larger than 100 nm, equal to or larger than 200 nm, equal to or larger than 300 nm, equal to or larger than 400 nm, or equal to or larger than 500 nm, and smaller than 5.0 μm, equal to or smaller than 4.5 μm, equal to or smaller than 4.0 μm, equal to or smaller than 3.5 μm, equal to or smaller than 3.0 μm, equal to or smaller than 2.5 μm, equal to or smaller than 2.0 μm, equal to or smaller than 1.5 μm, or equal to or smaller than 1.0 μm.

[0107] [Insulation layer 110] In the transistor 100 , the insulating layer 110 has, for example, a three-layer stacked structure. However, the insulating layer 110 may also have a two-layer or four-layer or more stacked structure.

[0108] As each layer constituting the insulating layer 110, an inorganic insulating film is preferably used. As the inorganic insulating film, for example, an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film can be cited. As the oxide insulating film, for example, a silicon oxide film, an aluminum oxide film, a magnesium oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, a tantalum oxide film, a cerium oxide film, a gallium zinc oxide film, and a hafnium aluminum oxide film can be cited. As the nitride insulating film, for example, a silicon nitride film and an aluminum nitride film can be cited. As the oxynitride insulating film, for example, a silicon oxynitride film, an aluminum oxynitride film, a gallium oxynitride film, an yttrium oxynitride film, and a hafnium oxynitride film can be cited. As the nitride oxide insulating film, for example, a silicon oxynitride film and an aluminum oxynitride film can be cited.

[0109] The insulating layer 110 includes a portion in contact with the semiconductor layer 108. When an oxide semiconductor is used as the semiconductor layer 108, in order to improve the interface characteristics between the semiconductor layer 108 and the insulating layer 110, it is preferable to use an oxide in at least a portion of the portion of the insulating layer 110 in contact with the semiconductor layer 108. Specifically, it is preferable to use an oxide in a portion of the insulating layer 110 in contact with the channel formation region of the semiconductor layer 108. The channel formation region is a high resistance region with a low carrier concentration. It can be said that the channel formation region is i-type (intrinsic) or substantially i-type.

[0110] A layer containing oxygen is preferably used as the insulating layer 110b which is in contact with the channel formation region of the semiconductor layer 108. The insulating layer 110b preferably includes a region containing a larger amount of oxygen than those of the insulating layers 110a and 110b.

[0111] The insulating layer 110b preferably uses one or more of the above-mentioned oxide insulating film and oxynitride insulating film. Specifically, the insulating layer 110b preferably uses one or both of a silicon oxide film and an oxynitride silicon film. When the insulating layer 110b is a layer with a high oxygen content, an i-type region is easily formed in the region in contact with the insulating layer 110b in the semiconductor layer 108 and in the vicinity thereof.

[0112] The insulating layer 110b is preferably a film that releases oxygen by heating. Since the insulating layer 110b releases oxygen due to heat applied in the manufacturing process of the transistor 100, oxygen can be supplied to the semiconductor layer 108. By supplying oxygen from the insulating layer 110b to the semiconductor layer 108, especially to the channel formation region of the semiconductor layer 108, oxygen vacancies in the semiconductor layer 108 can be reduced, and a transistor with good electrical characteristics and high reliability can be realized.

[0113] For example, oxygen can be supplied to the insulating layer 110b by performing heat treatment in an oxygen-containing atmosphere or plasma treatment in an oxygen-containing atmosphere. Alternatively, oxygen can be supplied by depositing an oxide film on the top surface of the insulating layer 110b by sputtering in an oxygen atmosphere. The oxide film can then be removed.

[0114] The insulating layer 110b is preferably formed by a deposition method such as sputtering or plasma enhanced chemical vapor deposition (PECVD) method. In particular, when sputtering is used, hydrogen gas does not need to be used as a deposition gas, thereby achieving a film with an extremely low hydrogen content. Therefore, the semiconductor layer 108 can be suppressed from being supplied with hydrogen to achieve stabilization of the electrical characteristics of the transistor 100.

[0115] It is preferable that the insulating layer 110a and the insulating layer 110c use a film that does not diffuse oxygen easily. Thus, it is possible to prevent the oxygen in the insulating layer 110b from passing through the substrate 102 side through the insulating layer 110a and the conductive layer 112b side through the insulating layer 110c due to heating. In other words, by sandwiching the insulating layer 110b above and below with the insulating layer 110a and the insulating layer 110c that do not diffuse oxygen easily, the oxygen in the insulating layer 110b can be confined. Thus, oxygen can be effectively supplied to the semiconductor layer 108.

[0116] In addition, the insulating layer 110a and the insulating layer 110c are preferably made of a film that does not easily diffuse hydrogen. This can prevent hydrogen from diffusing from the outside of the transistor through the insulating layer 110a or the insulating layer 110c to the semiconductor layer 108. Similarly, it can prevent hydrogen from diffusing from the conductive layer 103 through the insulating layer 110a to the channel formation region of the semiconductor layer 108.

[0117] The insulating layer 110a and the insulating layer 110c preferably use one or more of the above-mentioned oxide insulating film, nitride insulating film, oxynitride insulating film and nitride oxide insulating film, and preferably use one or more of silicon nitride film, silicon nitride oxide film, oxynitride silicon film, aluminum oxide film, oxynitride aluminum film, aluminum nitride film, hafnium oxide film and hafnium aluminum oxide film.

[0118] The insulating layers 110a and 110c are preferably made of one or more of the above-mentioned nitride insulating film and the nitride oxide insulating film. Specifically, the insulating layers 110a and 110c are preferably made of one or both of a silicon nitride film and a silicon nitride oxide film.

[0119] For example, the insulating layer 110a and the insulating layer 110c may be made of the above-mentioned film containing aluminum. For example, the insulating layer 110a and the insulating layer 110c may be made of an aluminum oxide film. The aluminum oxide film has a lower hydrogen content than the silicon nitride film and is therefore preferable.

[0120] The conductive layer 112a and the conductive layer 112b are oxidized due to oxygen contained in the insulating layer 110b, and the resistance sometimes increases. By providing the insulating layer 110a between the insulating layer 110b and the conductive layer 112a, it is possible to suppress the conductive layer 112a from being oxidized and the resistance from increasing. Similarly, by providing the insulating layer 110c between the insulating layer 110b and the conductive layer 112b, it is possible to suppress the conductive layer 112b from being oxidized and the resistance from increasing. At the same time, the amount of oxygen supplied from the insulating layer 110b to the semiconductor layer 108 is increased, and oxygen vacancies in the semiconductor layer 108 can be reduced.

[0121] The thickness of the insulating layer 110a and the insulating layer 110c is preferably 5 nm or more, 10 nm or more, 20 nm or more, or 50 nm or more, and preferably 200 nm or less, 150 nm or less, or 100 nm or less. By making the thickness of the insulating layer 110a and the insulating layer 110c within the above range, oxygen vacancies in the semiconductor layer 108, particularly in the channel formation region, can be reduced. Note that the thicknesses of the insulating layer 110a and the insulating layer 110c may be the same or different.

[0122] For example, it is preferable that a silicon nitride film or an aluminum oxide film be used for the insulating layer 110 a and the insulating layer 110 c , and a silicon oxynitride film be used for the insulating layer 110 b .

[0123] [Semiconductor layer 108] There is no particular limitation on the semiconductor material used for the semiconductor layer 108. For example, a semiconductor composed of a single element or a compound semiconductor can be used. Examples of semiconductors composed of a single element include silicon or germanium. Examples of compound semiconductors include gallium arsenide and silicon germanium. In addition, examples of compound semiconductors include organic semiconductors, nitride semiconductors, and oxide semiconductors. Note that these semiconductor materials may also contain impurities as dopants.

[0124] There is no particular limitation on the crystallinity of the semiconductor material used for the semiconductor layer 108, and an amorphous semiconductor, a single crystal semiconductor, or a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part thereof) can be used. When a single crystal semiconductor or a crystalline semiconductor is used, degradation of transistor characteristics can be suppressed, so it is preferred.

[0125] The semiconductor layer 108 preferably includes a metal oxide having semiconductor characteristics (also referred to as an oxide semiconductor).

[0126] The band gap of the metal oxide used for the semiconductor layer 108 is preferably 2.0 eV or more, more preferably 2.5 eV or more.

[0127] As metal oxides that can be used for the semiconductor layer 108, for example, indium oxide, gallium oxide, and zinc oxide can be cited. The metal oxide preferably contains at least indium or zinc. In addition, the metal oxide preferably contains two or three selected from indium, element M, and zinc. Element M is a metal element or a semi-metal element having a high bond energy with oxygen, for example, a metal element or a semi-metal element having a higher bond energy with oxygen than indium. As element M, specifically, aluminum, gallium, tin, yttrium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zirconium, molybdenum, hafnium, tantalum, tungsten, lanthanum, cerium, neodymium, magnesium, calcium, strontium, barium, boron, silicon, germanium, and antimony can be cited. The element M contained in the metal oxide is preferably any one or more of the above elements, more preferably one or more selected from aluminum, gallium, tin, and yttrium, and further preferably gallium. Note that in this specification, etc., metal elements and semi-metal elements are sometimes collectively referred to as "metal elements", and the "metal elements" recorded in this specification, etc. sometimes include semi-metal elements.

[0128] The semiconductor layer 108 may be made of, for example, indium zinc oxide (In-Zn oxide, also referred to as IZO (registered trademark)), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium gallium oxide (In-Ga oxide), indium gallium aluminum oxide (In-Ga-Al oxide), indium gallium tin oxide (In-Ga-Sn oxide), gallium zinc oxide (Ga-Zn oxide, also referred to as GZO), aluminum zinc oxide (Al-Zn oxide, also referred to as AZO), indium aluminum zinc oxide (In-Ga-Sn oxide), or a combination thereof. (In-Al-Zn oxide, also recorded as IAZO), indium tin zinc oxide (In-Sn-Zn oxide, also recorded as ITZO (registered trademark)), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium zinc oxide (In-Ga-Zn oxide, also recorded as IGZO), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide, also recorded as IGZTO), indium gallium aluminum zinc oxide (In-Ga-Al-Zn oxide, also recorded as IGAZO, IGZAO or IAGZO), etc. Alternatively, indium tin oxide, gallium tin oxide (Ga-Sn oxide), aluminum tin oxide (Al-Sn oxide), etc. containing silicon can be used.

[0129] When the ratio of the number of atoms of indium to the total number of atoms of all metal elements in the metal oxide is increased, the field effect mobility of the transistor can be increased, and a transistor with a large on-state current can be realized.

[0130] Note that the metal oxide may also replace indium or contain one or more metal elements with a large periodic number in the periodic table in addition to indium. There is a tendency that the greater the orbital overlap of the metal element, the greater the carrier conduction in the metal oxide. Therefore, by including a metal element with a large periodic number in the periodic table, the field effect mobility of the transistor can sometimes be improved. As metal elements with a large periodic number in the periodic table, metal elements belonging to the 5th period and metal elements belonging to the 6th period can be cited. As the metal element, specifically, yttrium, zirconium, silver, cadmium, tin, antimony, barium, lead, bismuth, lanthanum, cerium, praseodymium, neodymium, promethium, samarium and europium can be cited. Note that lanthanum, cerium, praseodymium, neodymium, promethium, samarium and europium are called light rare earth elements.

[0131] In addition, the metal oxide may also contain one or more non-metallic elements. When the metal oxide contains non-metallic elements, the field effect mobility of the transistor may be improved by increasing the carrier concentration or narrowing the band gap. Examples of non-metallic elements include carbon, nitrogen, phosphorus, sulfur, selenium, fluorine, chlorine, bromine, and hydrogen.

[0132] Furthermore, when the ratio of the number of zinc atoms to the total number of atoms of all metal elements in the metal oxide is increased, the metal oxide has high crystallinity and the diffusion of impurities in the metal oxide can be suppressed. Therefore, the variation of the electrical characteristics of the transistor is suppressed and the reliability can be improved.

[0133] In addition, when the ratio of the number of atoms of the element M in the metal oxide relative to the sum of the number of atoms of all metal elements is increased, the formation of oxygen vacancies in the metal oxide can be suppressed. Therefore, the generation of carriers due to oxygen vacancies is suppressed, and a transistor with a small off-state current can be formed. In addition, the variation of the electrical characteristics of the transistor is suppressed and the reliability can be improved.

[0134] The electrical characteristics and reliability of the transistor differ depending on the composition of the metal oxide used for the semiconductor layer 108. Therefore, by varying the composition of the metal oxide according to the electrical characteristics and reliability required for the transistor, a semiconductor device having both excellent electrical characteristics and high reliability can be achieved.

[0135] When the metal oxide is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. Examples of the atomic ratio of the metal elements in such an In-M-Zn oxide include In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:3, In:M:Zn=3:1:1, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:3, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, In:M:Zn=6:1:6, In:M:Zn=5:2:5, and compositions in the vicinity thereof. In addition, the composition in the vicinity includes a range of ±30% of the desired atomic ratio. By increasing the atomic ratio of indium in the metal oxide, the on-state current and field effect mobility of the transistor can be improved.

[0136] In addition, the atomic ratio of In in the In-M-Zn oxide may be smaller than the atomic ratio of M. Examples of atomic ratios of metal elements in such an In-M-Zn oxide include In:M:Zn=1:3:2, In:M:Zn=1:3:3, In:M:Zn=1:3:4, and compositions near these. By increasing the atomic ratio of M in the metal oxide, the generation of oxygen vacancies can be suppressed.

[0137] Note that when a plurality of metal elements are included as the element M, the total of the ratios of the number of atoms of the metal elements may be the ratio of the number of atoms of the element M.

[0138] In this specification, etc., the ratio of the number of atoms of indium to the total number of atoms of all metal elements contained may be described as the content rate of indium. The same applies to other metal elements.

[0139] The metal oxide can be formed by sputtering or atomic layer deposition (ALD) as appropriate. Note that when the metal oxide is formed by sputtering, the composition of the deposited metal oxide is sometimes different from the composition of the target. In particular, the zinc content in the deposited metal oxide is sometimes reduced to about 50% of that in the target.

[0140] The semiconductor layer 108 may also have a stacked structure including two or more metal oxide layers. The compositions of the two or more metal oxide layers included in the semiconductor layer 108 may also be the same or substantially the same as each other. By adopting a stacked structure of metal oxide layers with the same composition, for example, the same sputtering target can be used to form them, thereby reducing manufacturing costs.

[0141] The compositions of the two or more metal oxide layers included in the semiconductor layer 108 may also be different from each other. For example, a stacked structure of a first metal oxide layer having a composition of In:M:Zn=1:3:4 [atomic ratio] or a composition close thereto and a second metal oxide layer having a composition of In:M:Zn=1:1:1 [atomic ratio] or a composition close thereto disposed on the first metal oxide layer may be appropriately used. In addition, gallium, aluminum, or tin is particularly preferably used as the element M. The element M in the first metal oxide layer and the second metal oxide layer may be the same or different from each other. For example, the first metal oxide layer and the second metal oxide layer may also be IGZO layers having different compositions from each other.

[0142] In addition, for example, a stacked structure of a first metal oxide layer with a composition of In:Zn=4:1 [atomic ratio] or thereabouts and a second metal oxide layer with a composition of In:M:Zn=1:1:1 [atomic ratio] or thereabouts provided on the first metal oxide layer can be appropriately adopted.

[0143] For example, a stacked-layer structure selected from any one of indium oxide, indium gallium oxide, and IGZO, and any one of IAZO, IAGZO, and ITZO (registered trademark) can be used.

[0144] The semiconductor layer 108 preferably includes a crystalline metal oxide layer. Examples of the structure of the crystalline metal oxide include a CAAC (c-axis aligned crystal) structure, a polycrystalline structure, and a microcrystalline (nc: nano-crystal) structure. By using a crystalline metal oxide layer for the semiconductor layer 108, the defect state density in the semiconductor layer 108 can be reduced, thereby realizing a semiconductor device with high reliability.

[0145] The higher the crystallinity of the metal oxide layer used for the semiconductor layer 108, the lower the defect state density in the semiconductor layer 108. On the other hand, by using a metal oxide layer with low crystallinity, a transistor capable of passing a large current can be realized.

[0146] The higher the substrate temperature (stage temperature) when forming the metal oxide layer, the more crystalline the metal oxide layer can be formed. In addition, the higher the ratio of the flow rate of the oxygen gas used during formation to the total flow rate of the deposition gas (hereinafter also referred to as the oxygen flow rate ratio), the more crystalline the metal oxide layer can be formed.

[0147] The semiconductor layer 108 may also have a stacked structure of two or more metal oxide layers having different crystallinity. For example, it may have a stacked structure of a first metal oxide layer and a second metal oxide layer disposed on the first metal oxide layer, and the second metal oxide layer may include a region having higher crystallinity than the first metal oxide layer. Alternatively, the second metal oxide layer may include a region having lower crystallinity than the first metal oxide layer. In this case, the compositions of the first metal oxide layer and the second metal oxide layer may also be different, the same, or substantially the same.

[0148] The thickness of the semiconductor layer 108 is preferably greater than 3 nm and less than 200 nm, more preferably greater than 3 nm and less than 100 nm, more preferably greater than 5 nm and less than 100 nm, more preferably greater than 10 nm and less than 100 nm, more preferably greater than 10 nm and less than 70 nm, more preferably greater than 15 nm and less than 70 nm, more preferably greater than 15 nm and less than 50 nm, more preferably greater than 20 nm and less than 50 nm.

[0149] When an oxide semiconductor is used for the semiconductor layer 108, hydrogen in the oxide semiconductor reacts with oxygen bonded to a metal atom to form water, thereby forming an oxygen vacancy (V) in the oxide semiconductor. O In addition, sometimes hydrogen enters the defect in the oxygen vacancy (hereinafter referred to as V O H) is used as a donor to generate electrons as carriers. In addition, sometimes electrons as carriers are generated due to the bonding of a portion of hydrogen to oxygen bonded to metal atoms. Therefore, transistors using oxide semiconductors containing a large amount of hydrogen tend to have a normally-on characteristic. In addition, because the hydrogen in the oxide semiconductor is easily moved due to heat, electric field, etc., when the oxide semiconductor contains a large amount of hydrogen, the reliability of the transistor may be reduced.

[0150] When an oxide semiconductor is used as the semiconductor layer 108, it is preferable to minimize the V O H to make it high purity intrinsic or substantially high purity intrinsic. In order to obtain this V O For an oxide semiconductor with sufficiently reduced H, it is important to: remove impurities such as water and hydrogen in the oxide semiconductor (sometimes referred to as dehydration or dehydrogenation treatment); and supply oxygen to the oxide semiconductor to repair oxygen vacancies. O An oxide semiconductor in which impurities such as H are sufficiently reduced is used for a channel formation region of a transistor to impart stable electrical characteristics. Note that a process of supplying oxygen to an oxide semiconductor to repair oxygen vacancies is sometimes referred to as an oxidation treatment.

[0151] When an oxide semiconductor is used as the semiconductor layer 108, the carrier concentration of the oxide semiconductor in a region serving as a channel formation region is preferably 1×1018 cm -3 Below, more preferably below 1×10 17 cm -3 , and more preferably less than 1×10 16 cm -3 , more preferably less than 1×10 13 cm -3 , and more preferably less than 1×10 12 cm -3 The lower limit of the carrier concentration of the oxide semiconductor in the region serving as the channel formation region is not particularly limited, and can be set to 1×10 -9 cm -3 .

[0152] Compared with transistors using amorphous silicon, transistors using oxide semiconductors (hereinafter referred to as OS transistors) have very high field effect mobility. In addition, the off-state current of the OS transistor is extremely small, and the charge stored in the capacitor connected in series with the transistor can be maintained for a long period of time. In addition, by using OS transistors, the power consumption of semiconductor devices can be reduced.

[0153] OS transistors have little change in electrical characteristics due to exposure to radiation, that is, they have high tolerance to radiation, so they can be appropriately used in environments where radiation may be incident. OS transistors can also be said to have high reliability with respect to radiation. For example, OS transistors can be appropriately used in pixel circuits of flat-panel detectors for X-rays. In addition, OS transistors can be appropriately used in semiconductor devices used in outer space. Examples of radiation include electromagnetic radiation (e.g., X-rays and gamma rays) and particle radiation (e.g., alpha rays, beta rays, proton radiation, and neutron radiation).

[0154] Examples of silicon that can be used for the semiconductor layer 108 include single crystal silicon, polycrystalline silicon, microcrystalline silicon, and amorphous silicon. Examples of polycrystalline silicon include low temperature polycrystalline silicon (LTPS: Low Temperature Poly Silicon).

[0155] A transistor using amorphous silicon as the semiconductor layer 108 can be formed on a large glass substrate and can be manufactured at low cost. A transistor using polycrystalline silicon as the semiconductor layer 108 has high field effect mobility and can operate at high speed. In addition, a transistor using microcrystalline silicon as the semiconductor layer 108 has higher field effect mobility than a transistor using amorphous silicon and can operate at high speed.

[0156] The semiconductor layer 108 may also include a layered material used as a semiconductor. A layered material is a general term for a group of materials having a layered crystalline structure. A layered crystalline structure is a structure in which layers formed by covalent bonds or ionic bonds are stacked by bonds such as van der Waals bonds that are weaker than covalent bonds and ionic bonds. The layered material has high conductivity in a unit layer, that is, has high two-dimensional conductivity. By using a material used as a semiconductor and having high two-dimensional conductivity in a channel formation region, a transistor with a large on-state current can be provided.

[0157] As the above-mentioned layered material, for example, graphene, silicene, chalcogenides, etc. can be cited. Chalcogenides are compounds containing oxygen group elements (belonging to group 16 elements). In addition, as chalcogenides, transition metal chalcogenides, group 13 chalcogenides, etc. can be cited. As transition metal chalcogenides that can be used as semiconductor layers of transistors, specifically molybdenum sulfide (typically MoS2), molybdenum selenide (typically MoSe2), molybdenum telluride (typically MoTe2), tungsten sulfide (typically WS2), tungsten selenide (typically WSe2), tungsten telluride (typically WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically HfSe2), zirconium sulfide (typically ZrS2), zirconium selenide (typically ZrSe2), etc. can be cited.

[0158] [Conductive layer 112a, conductive layer 112b, conductive layer 103, conductive layer 104] Conductive layer 112a, conductive layer 112b, conductive layer 103, and conductive layer 104 may have a single-layer structure or a stacked structure of two or more layers. As materials that can be used for conductive layer 112a, conductive layer 112b, conductive layer 103, and conductive layer 104, for example, one or more of chromium, copper, aluminum, gold, silver, zinc, tantalum, titanium, tungsten, manganese, nickel, iron, cobalt, molybdenum, and niobium, and alloys containing one or more of the above metals as components can be cited. Low-resistance conductive materials containing one or more of copper, silver, gold, and aluminum can be appropriately used for conductive layer 112a, conductive layer 112b, conductive layer 103, and conductive layer 104. Among them, copper or aluminum is particularly advantageous in mass productivity and is therefore preferred.

[0159] Conductive metal oxides (also referred to as oxide conductors) can be used for the conductive layers 112a, 112b, and 104. Examples of oxide conductors (OC) include indium oxide, zinc oxide, In-Sn oxide (ITO), In-Zn oxide, In-W oxide, In-W-Zn oxide, In-Ti oxide, In-Ti-Sn oxide, In-Sn-Si oxide (ITO containing silicon, also referred to as ITSO), zinc oxide to which gallium is added, and In-Ga-Zn oxide. In particular, conductive oxides containing indium are preferably used because they have high conductivity.

[0160] Oxygen vacancies are formed in metal oxides having semiconductor properties, and hydrogen is added to the oxygen vacancies to form donor levels near the conduction band. As a result, the conductivity of the metal oxide increases, and the metal oxide becomes a conductor. The metal oxide that becomes a conductor can be called an oxide conductor.

[0161] The conductive layers 112a, 112b, and 104 may have a stacked-layer structure of a conductive film containing the above-mentioned oxide conductor (metal oxide) and a conductive film containing a metal or an alloy. By using a conductive film containing a metal or an alloy, wiring resistance can be reduced.

[0162] A Cu-X alloy film (X is Mn, Ni, Cr, Fe, Co, Mo, Ta or Ti) may be applied as the conductive layer 112a, the conductive layer 112b, the conductive layer 103 and the conductive layer 104. By using the Cu-X alloy film, processing can be performed by a wet etching process, thereby reducing manufacturing costs.

[0163] Note that materials used for the conductive layer 112a, the conductive layer 112b, the conductive layer 103, and the conductive layer 104 may be the same or at least part of them may be different.

[0164] The conductive layer 112a and the conductive layer 112b include a portion in contact with the semiconductor layer 108. When an oxide semiconductor is used as the semiconductor layer 108, when an easily oxidized metal such as aluminum is used for the conductive layer 112a or the conductive layer 112b, an insulating oxide (for example, aluminum oxide) is formed between the conductive layer 112a or the conductive layer 112b and the semiconductor layer 108, so that conduction between these layers may be hindered. Therefore, it is preferable to use a conductive material that is not easily oxidized, a conductive material that maintains low resistance even if oxidized, or an oxide conductive material for the conductive layer 112a and the conductive layer 112b.

[0165] The conductive layer 112a and the conductive layer 112b are preferably made of, for example, titanium, tantalum nitride, titanium nitride, nitride containing titanium and aluminum, nitride containing tantalum and aluminum, ruthenium, ruthenium oxide, ruthenium nitride, oxide containing strontium and ruthenium, or oxide containing lanthanum and nickel. These are conductive materials that are not easily oxidized or materials that maintain conductivity even when oxidized, and are therefore preferred. Note that when the conductive layer 112a or the conductive layer 112b has a stacked-layer structure, it is preferred that a conductive material that is not easily oxidized be used for at least the layer in contact with the semiconductor layer 108.

[0166] In addition, the above-mentioned oxide conductors can be used for the conductive layers 112a and 112b. Specifically, conductive oxides such as indium oxide, zinc oxide, ITO, In-Zn oxide, In-W oxide, In-W-Zn oxide, In-Ti oxide, In-Ti-Sn oxide, In-Sn oxide containing silicon, and zinc oxide added with gallium can be used.

[0167] A nitride conductor may be used for the conductive layer 112a and the conductive layer 112b. Examples of the nitride conductor include tantalum nitride and titanium nitride.

[0168] For example, the conductive layer 112a and the conductive layer 112b may each have a single-layer structure of an oxide conductor film, a stacked-layer structure of a metal film and an oxide conductor film, or a stacked-layer structure of a metal film. An example of an oxide conductor film is an ITSO film. An example of a metal film is a single-layer structure of a tungsten film, a single-layer structure of a titanium film, a single-layer structure of a copper film, and a three-layer structure of a titanium film, an aluminum film, and a titanium film.

[0169] The conductive layer 103 is preferably made of a material having a higher conductivity than the conductive layer 112a. Thus, the conductive layer 103 can be effectively used as an auxiliary wiring for the conductive layer 112a. As the conductive layer 103, for example, one or more of copper, aluminum, titanium, tungsten, and molybdenum, or an alloy containing one or more of the above metals as components can be appropriately used.

[0170] For example, an ITSO film is preferably used for the conductive layer 112a and the conductive layer 112b. For example, a titanium film is preferably used for the conductive layer 103. For example, a three-layer stacked structure of a titanium film, an aluminum film, and a titanium film is preferably used for the conductive layer 104.

[0171] [Insulating layer 106] The insulating layer 106 may have a single-layer structure or a stacked-layer structure of two or more layers. The insulating layer 106 preferably includes one or more inorganic insulating films. Examples of the inorganic insulating film include an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film. Specific examples of these inorganic insulating films are as described above.

[0172] The insulating layer 106 has a portion in contact with the semiconductor layer 108. When an oxide semiconductor is used for the semiconductor layer 108, at least the film in contact with the semiconductor layer 108 among the films constituting the insulating layer 106 is preferably an oxide insulating film or an oxynitride insulating film as described above. Further, the insulating layer 106 is preferably made of a film that releases oxygen by heating.

[0173] Specifically, when the insulating layer 106 has a single-layer structure, the insulating layer 106 is preferably formed using a silicon oxide film or a silicon oxynitride film.

[0174] Alternatively, the insulating layer 106 may have a stacked-layer structure of an oxide insulating film or an oxynitride insulating film in contact with the semiconductor layer 108, and a nitride insulating film or an oxynitride insulating film in contact with the conductive layer 104. As the oxide insulating film or the oxynitride insulating film, for example, a silicon oxide film or a silicon oxynitride film is preferably used. As the nitride insulating film or the oxynitride insulating film, a silicon nitride film or a silicon oxynitride film is preferably used.

[0175] Silicon nitride films and silicon nitride oxide films have characteristics of rarely releasing impurities (for example, water and hydrogen) and not easily allowing oxygen and hydrogen to pass through, and thus can be suitably used as the insulating layer 106. Since diffusion of impurities from the insulating layer 106 to the semiconductor layer 108 is suppressed, good electrical characteristics of the transistor can be achieved and reliability can be improved.

[0176] Note that in a micro transistor, when the thickness of the gate insulating layer is small, the leakage current sometimes increases. By using a material with a high relative dielectric constant (also called a high-k material) for the gate insulating layer, it is possible to achieve low voltage when the transistor is operating while maintaining the physical thickness. As high-k materials that can be used for the insulating layer 106, for example, gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxynitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxynitrides containing silicon and hafnium, and nitrides containing silicon and hafnium can be cited.

[0177] [Substrate 102] Although there is no particular limitation on the material of the substrate 102, it is at least required to have heat resistance sufficient to withstand subsequent heat treatment. For example, a single crystal semiconductor substrate or polycrystalline semiconductor substrate made of silicon or silicon carbide, a compound semiconductor substrate such as silicon germanium, an SOI substrate, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, or a resin substrate can be used as the substrate 102. In addition, a semiconductor element may be provided on the substrate 102. Note that the shape of the semiconductor substrate and the insulating substrate may be circular or angular.

[0178] As the substrate 102, a flexible substrate may be used, and the transistor 100 and the like may be directly formed on the flexible substrate. Alternatively, a peeling layer may be provided between the substrate 102 and the transistor 100 and the like. The peeling layer may be used when a part or all of a semiconductor device is manufactured on the peeling layer, and then separated from the substrate 102 and transferred to another substrate. In this case, the transistor 100 and the like may also be transferred to a substrate with low heat resistance or a flexible substrate.

[0179] [Modification Example of Transistor 100] 4 to 9 show modified examples of the transistor 100 .

[0180] [Transistor 100A] Figure 4A A top view of transistor 100A is shown. Figure 4B It is along Figure 4A A cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 4C It is along Figure 4A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0181] The transistor 100A is different from the transistor 100 in that the transistor 100A includes a conductive layer 105 between the insulating layer 110c and the conductive layer 112b.

[0182] Conductive layer 105 is provided on insulating layer 110, and conductive layer 112b is provided on conductive layer 105. At least a portion of conductive layer 112b is in contact with the top surface of conductive layer 105. Conductive layer 105 can be used as one or both of auxiliary wiring and wiring of conductive layer 112b. Opening 143 is provided in conductive layer 105.

[0183] The semiconductor layer 108 is preferably in contact with the side surface of the conductive layer 105. The semiconductor layer 108 is preferably provided in contact with an end portion of the conductive layer 105 on the side of the opening 143 (which may also be referred to as a side wall of the opening 143).

[0184] In addition, a metal oxide may be formed between the conductive layer 105 and the semiconductor layer 108. Specifically, the side surface of the conductive layer 105 in the opening 143 may be oxidized due to contact with the semiconductor layer 108. Depending on the material of the conductive layer 105, oxidation may occur, so that the conductivity of the conductive layer 105 decreases. Since the conductive layer 105 and the semiconductor layer 108 may not be electrically connected, the side surface of the conductive layer 105 in the opening 143 may be oxidized. For example, an oxide containing the same metal as the metal contained in the conductive layer 105 may exist between the conductive layer 105 and the semiconductor layer 108.

[0185] As described in the transistor 100 , when an oxide semiconductor is used for the semiconductor layer 108 , it is preferable that a conductive layer in contact with the semiconductor layer 108 be made of a material that maintains conductivity even when oxidized, such as an oxide conductor.

[0186] On the other hand, as the wiring, it is preferable to use a material with lower resistance than that of the oxide conductor, such as a metal or an alloy. Therefore, it is preferable to use a material with higher conductivity than that of the conductive layer 112b, such as a metal or an alloy, for the conductive layer 105. The conductive layer 105 can use a material that can be used for the conductive layer 103.

[0187] In the semiconductor layer 108, a region in contact with the conductive layer 105 (or an oxide of the conductive layer 105) is used as a low resistance region.

[0188] When the conductive layer 105 is in contact with the semiconductor layer 108, the conductive layer 105 extracts oxygen contained in the semiconductor layer 108 due to the heat applied in the manufacturing process of the transistor 100A, thereby easily forming oxygen vacancies in the semiconductor layer 108. When impurities such as hydrogen enter the oxygen vacancies, the impurities are used as donors and the carrier concentration is easily increased. Therefore, the region in the semiconductor layer 108 that is in contact with the conductive layer 105 and its vicinity can be made into a low resistance region.

[0189] In the semiconductor layer 108 of the transistor 100A, a region in contact with the conductive layer 103 as a low resistance region is provided between a region in contact with the conductive layer 112a and a region in contact with the insulating layer 110c as an i-type region. Here, when the conductive layer 112a is used as a drain electrode and the conductive layer 112b is used as a source electrode, it can also be said that the semiconductor layer 108 includes a low resistance region between the region in contact with the drain electrode and the channel formation region. As a result, a high electric field is less likely to be generated near the drain region, and generation of hot carriers can be suppressed, thereby suppressing transistor degradation.

[0190] In addition, in the semiconductor layer 108 of the transistor 100A, a region in contact with the conductive layer 105 as a low resistance region is provided between a region in contact with the conductive layer 112b and a region in contact with the insulating layer 110c as an i-type region. Here, when the conductive layer 112a is used as a source electrode and the conductive layer 112b is used as a drain electrode, it can also be said that the semiconductor layer 108 includes a low resistance region between the region in contact with the drain electrode and the channel formation region. As a result, a high electric field is less likely to be generated near the drain region, and generation of hot carriers can be suppressed, thereby suppressing transistor degradation.

[0191] Thus, the transistor of one embodiment of the present invention can have high reliability even when the conductive layer 112a or the conductive layer 112b is a drain electrode. Therefore, the degree of freedom in designing the semiconductor device can be increased.

[0192] An area in contact with the conductive layer 103, an area in contact with the insulating layer 110, and an area in contact with the conductive layer 105 are sequentially arranged between an area in contact with the conductive layer 112a and an area in contact with the conductive layer 112b of the semiconductor layer 108. The insulating layer 110 has a three-layer structure, wherein the insulating layer 110b is sandwiched above and below by the insulating layer 110a and the insulating layer 110c. Furthermore, the insulating layer 110 is sandwiched above and below by the conductive layer 105 and the conductive layer 103. In other words, the stacked body in contact with the semiconductor layer 108 has a symmetrical structure based on a line perpendicular to the up and down direction (stacked direction). As a result, the semiconductor layer 108 can have an appropriate carrier concentration distribution in the channel length direction. As a result, the transistor can have good electrical characteristics and high reliability.

[0193] [Transistor 100B] Figure 5A A top view of transistor 100B is shown. Figure 5B It is along Figure 5A A cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 5C It is along Figure 5A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0194] The transistor 100B is different from the transistor 100 in that the transistor 100B includes an insulating layer 110d between the insulating layer 110c and the conductive layer 112b.

[0195] The insulating layer 110d is preferably a layer that releases hydrogen when heated. The insulating layer 110d releases hydrogen due to heat applied in a step of manufacturing the transistor 100, and hydrogen can be supplied to the semiconductor layer 108. Thus, a low-resistance region can be formed near a region of the semiconductor layer 108 that is in contact with the conductive layer 112b.

[0196] For example, the insulating layer 110d includes a region having a higher hydrogen content than that of the insulating layer 110a. In addition, the insulating layer 110d preferably includes a region having a higher hydrogen content than that of the insulating layer 110c.

[0197] When the insulating layer 110d is a layer with a high hydrogen content, the resistance of a region in the semiconductor layer 108 that is in contact with the insulating layer 110d and its vicinity can be reduced.

[0198] The insulating layer 110c has a lower hydrogen content than the insulating layer 110d. Therefore, diffusion of hydrogen from the insulating layer 110d into a region (region to be converted to i-type) in the insulating layer 110b and the semiconductor layer 108 to which a sufficient gate electric field is applied can be suppressed.

[0199] The insulating layer 110d preferably uses one or more of the above-mentioned oxide insulating film, nitride insulating film, oxynitride insulating film and nitride oxide insulating film, and preferably uses one or more of silicon nitride film, silicon nitride oxide film, oxynitride silicon film, aluminum oxide film, oxynitride aluminum film, aluminum nitride film, hafnium oxide film and hafnium aluminum oxide film.

[0200] The insulating layer 110d is preferably made of one or more of the above-mentioned nitride insulating film and the nitride oxide insulating film. Specifically, the insulating layer 110d is preferably made of one or both of a silicon nitride film and a silicon nitride oxide film.

[0201] The silicon nitride film and the silicon nitride oxide film can realize a film that releases very little impurities (for example, water and hydrogen) and does not easily allow oxygen and hydrogen to pass through, so they can be appropriately used as the insulating layer 110a and the insulating layer 110c. In addition, by changing the deposition conditions (for example, the deposition gas or the power during deposition), the silicon nitride film and the silicon nitride oxide film can be changed to a film that releases a large amount of hydrogen, so they can also be appropriately used as the insulating layer 110d.

[0202] The content of hydrogen is less than that of main components constituting the insulating layer (for example, nitrogen and silicon of the silicon nitride layer), and therefore the hydrogen contents of the layers constituting the insulating layer 110 are preferably compared by SIMS analysis.

[0203] Even if the insulating layer 110c and the insulating layer 110d are made of the same main component (for example, both are silicon nitride layers), they can sometimes be distinguished by cross-sectional observation. For example, in a transmission electron (TE) image of a scanning transmission electron microscope (STEM), it is observed that the brightness of the insulating layer 110d is higher than that of the insulating layer 110c.

[0204] In the semiconductor layer 108 of the transistor 100B, a region in contact with the conductive layer 103 as a low resistance region is provided between a region in contact with the conductive layer 112a and a region in contact with the insulating layer 110c as an i-type region. Here, when the conductive layer 112a is used as a drain electrode and the conductive layer 112b is used as a source electrode, it can also be said that the semiconductor layer 108 includes a low resistance region between the region in contact with the drain electrode and the channel formation region. As a result, a high electric field is less likely to be generated near the drain region, and generation of hot carriers can be suppressed, thereby suppressing transistor degradation.

[0205] In the semiconductor layer 108 of the transistor 100B, a region in contact with the insulating layer 110d as a low resistance region is provided between a region in contact with the conductive layer 112b and a region in contact with the insulating layer 110c as an i-type region. Here, when the conductive layer 112a is used as a source electrode and the conductive layer 112b is used as a drain electrode, it can also be said that the semiconductor layer 108 includes a low resistance region between the region in contact with the drain electrode and the channel formation region. As a result, a high electric field is not easily generated near the drain region, and the generation of hot carriers can be suppressed, thereby suppressing the degradation of the transistor.

[0206] Thus, the transistor of one embodiment of the present invention can have high reliability even when the conductive layer 112a or the conductive layer 112b is a drain electrode. Therefore, the degree of freedom in designing the semiconductor device can be increased.

[0207] An area in contact with the conductive layer 103 and an area in contact with the insulating layer 110 are provided between an area in contact with the conductive layer 112a and an area in contact with the conductive layer 112b of the semiconductor layer 108. The insulating layer 110b is sandwiched above and below by the insulating layer 110a and the insulating layer 110c, and the three-layer structure is sandwiched above and below by the conductive layer 103 and the insulating layer 110d. Here, the common point of the conductive layer 103 and the insulating layer 110d is to make the semiconductor layer 108 low-resistance. In other words, the stacked body in contact with the semiconductor layer 108 can be considered to have a symmetrical structure based on a line perpendicular to the up and down direction (stacked direction). As a result, the semiconductor layer 108 can have an appropriate carrier concentration distribution in the channel length direction. As a result, the transistor can have good electrical characteristics and high reliability.

[0208] [Transistor 100C] Fig. 6A A top view of transistor 100C is shown. Figure 6B It is along Fig. 6A A cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 6C It is along Fig. 6A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0209] The main difference between the transistor 100C and the transistor 100 is that when the transistor 100C is viewed from a plan view, the opening 143 is larger than the opening 141 and the opening 148 .

[0210] The end of the conductive layer 112 b on the opening 143 side is located outside the end of the insulating layer 110 on the opening 141 side.

[0211] The semiconductor layer 108 is in contact with the top surface and side surfaces of the conductive layer 112 b , the side surfaces of the insulating layer 110 , the side surfaces of the conductive layer 103 , and the top surface of the conductive layer 112 a .

[0212] In the transistor 100C, the step of the surface on which the semiconductor layer 108 is formed is smaller than that of the transistor 100 , and thus the coverage of the semiconductor layer 108 can be improved in some cases.

[0213] [Transistor 100D] Fig. 7A A top view of transistor 100D is shown. Figure 7B It is along Fig. 7A The cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 7C It is along Fig. 7A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0214] The transistor 100D is different from the transistor 100 in that, in the transistor 100D, the semiconductor layer 108 is in contact with the side surface of the conductive layer 112 b that does not face the opening 143 (the side opposite to the opening 143 ).

[0215] There is no particular limitation on the top surface shape and size of the semiconductor layer 108 and the conductive layer 112b. The end of the semiconductor layer 108 may be aligned with the end of the conductive layer 112b, may be located inside the end of the conductive layer 112b, or may be located outside the end of the conductive layer 112b.

[0216] like Figure 7B As shown in FIG. 1 , the semiconductor layer 108 of the transistor 100D covers the side of the conductive layer 112b that does not face the opening 143. The end of the semiconductor layer 108 is located outside the end of the conductive layer 112b and contacts the insulating layer 110. Figure 7C The left side (B1 side) of the semiconductor layer 108 covers the end of the conductive layer 112b and contacts the insulating layer 110. Figure 7C The right side (B2 side) portion of the electrode contacts the conductive layer 112b.

[0217] [Transistor 100E] Fig. 8A A top view of transistor 100E is shown. Figure 8B It is along Fig. 8A The cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 8C It is along Fig. 8A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0218] The difference between the transistor 100E and the transistor 100 is that the transistor 100E has a top contact structure in which the top surface of the semiconductor layer 108 contacts the conductive layer 112 b .

[0219] like Figure 8BAs shown, the conductive layer 112 b of the transistor 100E covers the top surface and side surfaces (also referred to as the end portions of the semiconductor layer 108 ) of the semiconductor layer 108 located on the insulating layer 110 .

[0220] [Transistor 100F] Fig. 9A A cross-sectional view of transistor 100F is shown.

[0221] The transistor 100F is different from the transistor 100B in that the transistor 100F includes a conductive layer 109 serving as a back gate electrode on the insulating layer 110a, and includes an insulating layer 110e on the insulating layer 110a and the conductive layer 109. Note that although an example in which a back gate electrode is added to the transistor 100B is shown here, a back gate electrode may be provided in other transistors described in this embodiment.

[0222] The conductive layer 109 is located on the insulating layer 110a. The conductive layer 109 is electrically insulated from the conductive layer 112a and the conductive layer 103 by the insulating layer 110a. An opening is provided at a position overlapping with the conductive layer 112a in the conductive layer 109. An opening of the insulating layer 110 exists inside the opening of the conductive layer 109. Thus, a structure in which the conductive layer 109 and the semiconductor layer 108 have no region in contact with each other can be obtained.

[0223] The insulating layer 110 includes an insulating layer 110a on the conductive layer 103, an insulating layer 110e on the insulating layer 110a and the conductive layer 109, an insulating layer 110b on the insulating layer 110e, an insulating layer 110c on the insulating layer 110b, and an insulating layer 110d on the insulating layer 110c.

[0224] The insulating layer 110e covers the top surface and the side surfaces of the conductive layer 109. The insulating layer 110e is provided so as to cover a part of the opening of the conductive layer 109. The insulating layer 110e is in contact with the insulating layer 110a through the opening of the conductive layer 109.

[0225] The insulating layer 110e preferably has the same structure as the insulating layers 110a and 110c. Specifically, the insulating layer 110e preferably uses a film in which oxygen is not easily diffused. In addition, the insulating layer 110e preferably uses a film in which hydrogen is not easily diffused.

[0226] In the transistor 100F, the semiconductor layer 108 has a region that overlaps with the conductive layer 104 via the insulating layer 106 and overlaps with the conductive layer 109 via a portion of the insulating layer 110 (particularly, the insulating layer 110b and the insulating layer 110e). In other words, the semiconductor layer 108 has a region that is sandwiched between the conductive layer 104 and the conductive layer 109 via the insulating layer 106 and a portion of the insulating layer 110 (particularly, the insulating layer 110b and the insulating layer 110e).

[0227] The conductive layer 109 functions as a back gate electrode of the transistor 100F. In addition, a portion of the insulating layer 110 functions as a back gate insulating layer of the transistor 100F.

[0228] By providing the back gate electrode in the transistor 100F, the potential of the back gate electrode side (also referred to as the back channel) of the semiconductor layer 108 can be fixed, and the saturation of the Id-Vd characteristic of the transistor 100F can be improved.

[0229] In this specification and the like, a case where a current change in a saturation region in the Id-Vd characteristics of a transistor is small (the gradient is small) may be expressed as “high saturation”.

[0230] In addition, since the transistor 100F has a back gate electrode, the back channel potential of the semiconductor layer 108 can be fixed. Therefore, in an n-type transistor, the negative drift of the threshold voltage can be suppressed. Thus, a transistor with a normally closed characteristic (that is, a threshold voltage with a positive value) can be realized. In addition, in a p-type transistor, the positive drift of the threshold voltage can be suppressed, thereby realizing a transistor with a normally closed characteristic (that is, a threshold voltage with a negative value).

[0231] Fig. 9A An example is shown in which the thickness of the insulating layer 110a is uniform in any part. Note that the insulating layer 110a may have a different thickness between a region overlapping the conductive layer 109 and a region not overlapping the conductive layer 109. For example, when processing a film to be the conductive layer 109, a portion of the insulating layer 110a in the region not overlapping the conductive layer 109 may be removed, thereby reducing its thickness.

[0232] In the semiconductor layer 108, at least a region in contact with the insulating layer 110b is used as a channel formation region. In the description of this embodiment, a region in contact with the insulating layer 110e in the semiconductor layer 108 is not included in the channel formation region, but this region may be included in the channel formation region.

[0233] Fig. 9A The dotted double arrow indicates the channel length L100 of the transistor 100. The channel length L100 can be said to be the shortest distance between a portion of the semiconductor layer 108 that contacts the insulating layer 110d and a portion that contacts the insulating layer 110e when viewed in cross section.

[0234] like Fig. 9A As shown, the channel length L100 is sometimes affected by the thickness T109 of the conductive layer 109 according to the shortest distance L1 between the conductive layer 109 and the semiconductor layer 108 .

[0235] The channel length L100 of the transistor corresponds to the length of the side surface of the opening side of the insulating layer 110b when viewed from a cross section. When the distance between the conductive layer 109 and the semiconductor layer 108 is close (that is, the distance L1 is shortened), the channel length L100 is sometimes increased due to the influence of the thickness of the conductive layer 109. Therefore, the channel length L100 may be more than 1 times, more than 1.5 times, or more than 2 times the thickness T110.

[0236] [Transistor 100G] Fig. 9B A cross-sectional view of transistor 100G is shown.

[0237] The transistor 100G is different from the transistor 100F in that in the transistor 100G, the insulating layer 110 has a seven-layer structure.

[0238] The insulating layer 110 includes an insulating layer 110a on the conductive layer 103, an insulating layer 110b1 on the insulating layer 110a, an insulating layer 110e1 on the insulating layer 110b1, an insulating layer 110e2 on the insulating layer 110e1 and the conductive layer 109, an insulating layer 110b2 on the insulating layer 110e2, an insulating layer 110c on the insulating layer 110b2, and an insulating layer 110d on the insulating layer 110c.

[0239] The insulating layer 110b1 and the insulating layer 110b2 may use the same structure as that of the insulating layer 110b. Specifically, the insulating layer 110b1 and the insulating layer 110b2 may preferably use a layer containing oxygen, and may preferably have a region containing more oxygen than at least one of the insulating layers 110a, 110c, 110d, 110e1, and 110e2.

[0240] The insulating layer 110e1 and the insulating layer 110e2 may use the same structure as that used for the insulating layer 110e. Specifically, the insulating layer 110e1 and the insulating layer 110e2 are preferably both made of a film in which oxygen does not diffuse easily. In addition, the insulating layer 110e1 and the insulating layer 110e2 are preferably both made of a film in which hydrogen does not diffuse easily.

[0241] The insulating layers 110 a , 110 c , and 110 d may all use the above-mentioned structure.

[0242] exist Fig. 9B In the embodiment, the channel length L100 may be the shortest distance between a portion of the semiconductor layer 108 that contacts the insulating layer 110 a and a portion of the semiconductor layer 108 that contacts the insulating layer 110 c .

[0243] With such a structure, the insulating layer 110 can have a structure symmetrical to the conductive layer 109 in the upper and lower directions. In addition, since oxygen can be supplied to the semiconductor layer 108 from both the insulating layers 110b1 and 110b2, transistor characteristics can be improved.

[0244] [Specific example of semiconductor device] FIG10 is a circuit diagram of a semiconductor device according to one embodiment of the present invention. FIG11 to FIG16 are top views and cross-sectional views of a semiconductor device according to one embodiment of the present invention. Hereinafter, transistor 100 is mainly used as an example of a transistor included in a semiconductor device according to one embodiment of the present invention. A semiconductor device according to one embodiment of the present invention is not limited thereto, and may also include one or more of the above-mentioned transistors 100A to 100G.

[0245] A semiconductor device according to one embodiment of the present invention includes at least two transistors, and any one of a gate, a source, and a drain of one transistor is electrically connected to any one of a gate, a source, and a drain of another transistor.

[0246] For example, Fig. 10A The semiconductor device shown includes a transistor 100 and a transistor 200. One of a source and a drain of the transistor 200 is electrically connected to the gate of the transistor 100.

[0247] Notice, FIG. 10A to FIG. 10C Although the transistor 100 and the transistor 200 shown in the figure are n-channel transistors, one embodiment of the present invention is not limited thereto, and one or both of the transistor 100 and the transistor 200 may be p-channel transistors.

[0248] [Semiconductor device 10] FIG. 11A to FIG. 11C FIG. 1 is a cross-sectional view of a semiconductor device 10 . The semiconductor device 10 includes a transistor 100 and a transistor 150 . In the semiconductor device 10 , any one of the gate, source, and drain of the transistor 100 can be electrically connected to any one of the gate, source, and drain of the transistor 150 .

[0249] The transistor 100 is provided over a substrate 102. Since the transistor 100 has the structure described above, detailed description thereof will be omitted (see FIGS. 1 and 2).

[0250] Fig.11A Equivalent to following Figure 1A A cross-sectional view of transistor 100 and transistor 150 in the direction of dot-dash line A1-A2 in FIG. Fig. 11B Equivalent to following Figure 1A A cross-sectional view of the transistor 100 along the dot-dash line B1-B2 in FIG. Fig. 11C Equivalent to following Fig. 11BA cross-sectional view of transistor 150 in the same direction.

[0251] The transistor 150 includes a conductive layer 112c, a conductive layer 103a, an insulating layer 110 (insulating layers 110a, 110b, and 110c), an insulating layer 110s, a semiconductor layer 108a, an insulating layer 106, a conductive layer 107a, a conductive layer 107b, and a conductive layer 104a. Each layer constituting the transistor 150 may have a single-layer structure or a stacked-layer structure.

[0252] A conductive layer 112c is provided over the substrate 102, and a conductive layer 103a is provided over the conductive layer 112c. The conductive layer 112c and the conductive layer 103a serve as a back gate electrode of the transistor 150. The conductive layer 112c can be formed using the same material and process as the conductive layer 112a. In addition, the conductive layer 103a can be formed using the same material and process as the conductive layer 103. Note that the transistor 150 does not necessarily include a back gate electrode.

[0253] The insulating layer 110 is provided so as to cover the conductive layer 112c and the conductive layer 103a, and the insulating layer 110s is provided on the insulating layer 110. The insulating layer 110 and the insulating layer 110s function as a back gate insulating layer of the transistor 150. Since the insulating layer 110s is in contact with the channel formation region of the semiconductor layer 108a, it is preferable that the insulating layer 110s is an insulating layer containing oxygen. For example, the insulating layer 110s can use a material that is suitable for the insulating layer 110b.

[0254] The semiconductor layer 108a is provided on the insulating layer 110s. The semiconductor layer 108a has a region overlapping with the conductive layers 112c and 103a via the insulating layer 110 and the insulating layer 110s. The semiconductor layer 108a can be formed using the same material and process as the semiconductor layer 108.

[0255] Here, the semiconductor layer 108 and the semiconductor layer 108a may be made of the same material or different materials. In addition, the semiconductor layer 108 and the semiconductor layer 108a may be made of materials having different compositions. For example, the semiconductor layer 108 and the semiconductor layer 108a may both use In-Ga-Zn oxide of the same composition. In addition, the semiconductor layer 108 and the semiconductor layer 108a may both use In-Ga-Zn oxide, wherein the atomic ratio of In in the metal oxide of one is greater than that of the other. In addition, one of the semiconductor layer 108 and the semiconductor layer 108a may use In-Ga-Zn oxide and the other may use In-Zn oxide.

[0256] The insulating layer 106 is provided so as to cover the insulating layer 110 s and the semiconductor layer 108 a . The insulating layer 106 functions as a gate insulating layer of the transistor 150 .

[0257] A conductive layer 104a is provided over the insulating layer 106. The conductive layer 104a includes a region overlapping with the semiconductor layer 108a via the insulating layer 106. The conductive layer 104a serves as a gate electrode of the transistor 150. The conductive layer 104a can be formed using the same material and process as those of the conductive layer 104.

[0258] An insulating layer 195 is provided so as to cover the conductive layer 104a, and a conductive layer 107a and a conductive layer 107b are provided over the insulating layer 195. The conductive layer 107a and the conductive layer 107b are in contact with the semiconductor layer 108a through openings provided in the insulating layer 106 and the insulating layer 195. One of the conductive layer 107a and the conductive layer 107b serves as a source electrode of the transistor 150, and the other serves as a drain electrode.

[0259] The insulating layer 195 is used as a protective layer. The insulating layer 195 is preferably made of a material in which impurities are not easily diffused. By providing the insulating layer 195, it is possible to effectively suppress the diffusion of impurities from the outside into the transistor, thereby improving the reliability of the semiconductor device. As impurities, water and hydrogen can be cited, for example. For example, the insulating layer 195 includes one or both of an inorganic insulating layer and an organic insulating layer. The insulating layer 195 may also have a stacked structure of an inorganic insulating layer and an organic insulating layer.

[0260] As the inorganic insulating film that can be used for the insulating layer 195, for example, an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film can be cited. Specific examples of these inorganic insulating films have been given in the description of the insulating layer 110. More specifically, one or more of silicon nitride, silicon nitride oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, aluminum nitride, hafnium oxide, and hafnium aluminum oxide can be used for the insulating layer 195. For example, one or more of acrylic resin and polyimide resin can be used for the insulating layer 195 as an organic material.

[0261] Fig. 11C An example is shown in which the conductive layer 104a is not connected to the conductive layer 103a. For example, a constant potential may be supplied to the back gate, and a signal for driving the transistor 150 may be supplied to the gate. Thus, a threshold voltage when driving the transistor 150 can be controlled by the potential supplied to the back gate.

[0262] Alternatively, the conductive layer 104a may be connected to the conductive layer 103a through openings provided in the insulating layer 106 and the insulating layer 110. Thus, the gate and the back gate are supplied with the same potential, and the current that can flow when the transistor 150 is in the on state can be increased. Furthermore, the current that flows when the transistor 150 is in the off state can be reduced.

[0263] Alternatively, the conductive layer 107a or the conductive layer 107b may be connected to the conductive layer 103a through an opening provided in the insulating layer 106 and the insulating layer 110. By supplying the same potential to the source and the back gate, the back channel potential is stabilized, and the saturation of the Id-Vd characteristic of the transistor can be improved.

[0264] The transistor 150 is a so-called top-gate transistor having a gate electrode above the semiconductor layer 108a. For example, by adding an impurity element to the semiconductor layer 108a using the conductive layer 104a used as the gate electrode as a mask, a source region and a drain region can be formed in a self-aligned manner. The transistor 150 can be said to be a TGSA (Top Gate Self-Aligned) type transistor.

[0265] The channel length of transistor 150 can be controlled by the width of conductive layer 104a in the channel length direction. Thus, the channel length of transistor 150 is a value greater than the limiting resolution of an exposure device used in manufacturing the transistor. By increasing the channel length, a transistor with high saturation characteristics can be realized.

[0266] In the manufacture of the semiconductor device 10, the transistor 100 with a small channel length and the transistor 150 with a large channel length can share some processes and be formed on the same substrate. For example, the transistor 100 is applied to a transistor that requires a large on-state current, and the transistor 150 is applied to a transistor that requires a high saturation characteristic, thereby realizing a high-performance semiconductor device.

[0267] [Semiconductor Device 10A] Fig. 10B A circuit diagram of a semiconductor device 10A is shown. Fig. 12A A top view of the semiconductor device 10A is shown. Fig. 12B It is along Fig. 12A The cross-sectional view along the dot-dash line A1-A2 in FIG. Fig.13A It is along Fig. 12A The cross-sectional view along the dot-dash line B1-B2 in FIG. Fig. 13B It is along Fig. 12A Cross-sectional view along the dot-dash line B3-B4.

[0268] The semiconductor device 10A includes a transistor 100 and a transistor 200 . The other of the source and the drain of the transistor 200 is electrically connected to the other of the source and the drain of the transistor 100 .

[0269] The transistor 100 and the transistor 200 are both formed on a substrate 102 .

[0270] Since the transistor 100 has the structure described above, detailed description thereof will be omitted (see FIGS. 1 and 2 ).

[0271] The transistor 200 includes a conductive layer 112c, a conductive layer 103a, a semiconductor layer 108a, a conductive layer 112b, an insulating layer 106, and a conductive layer 104a.

[0272] The conductive layer 112c functions as one of a source electrode and a drain electrode of the transistor 200. The conductive layer 112c can be formed using the same material and process as those of the conductive layer 112a.

[0273] The semiconductor layer 108a can be formed using the same material in the same process as the semiconductor layer 108. Alternatively, the semiconductor layer 108 and the semiconductor layer 108a can be formed using different materials in different processes.

[0274] The conductive layer 112b is used as the other of the source electrode and the drain electrode of the transistor 100 and is used as the other of the source electrode and the drain electrode of the transistor 200. When the transistor 100 and the transistor 200 use the conductive layer 112b in common, the occupied area of ​​the semiconductor device can be reduced.

[0275] The conductive layer 104a serves as a gate electrode of the transistor 200. The conductive layer 104a can be formed using the same material and process as those of the conductive layer 104.

[0276] Note that the opening diameter of the opening 146 provided in the conductive layer 112b, the insulating layer 110, and the conductive layer 103 may be the same as or different from the opening diameter of the opening 146a provided in the conductive layer 112b, the insulating layer 110, and the conductive layer 103a. By setting the two opening diameters respectively, two transistors having different channel widths can also be manufactured. In addition, the shape of the opening 146 and the shape of the opening 146a may be the same as or different.

[0277] [Semiconductor device 10B] Fig. 10C A circuit diagram of a semiconductor device 10B is shown. Fig.14A A top view of the semiconductor device 10B is shown. Fig. 14B It is along Fig.14A The cross-sectional view along the dot-dash line A1-A2 in FIG. Fig. 14C It is along Fig.14A Cross-sectional view along the dot-dashed line B1-B2 in FIG.

[0278] The semiconductor device 10B includes a transistor 100 and a transistor 200 . One of a source and a drain of the transistor 200 is electrically connected to one of a source and a drain of the transistor 100 .

[0279] The transistor 100 and the transistor 200 are both formed on a substrate 102 .

[0280] Since the transistor 100 has the structure described above, detailed description thereof will be omitted (see FIGS. 1 and 2 ).

[0281] The transistor 200 includes a conductive layer 112c, a conductive layer 103, a semiconductor layer 108a, a conductive layer 112a, an insulating layer 106, and a conductive layer 104a.

[0282] The conductive layer 112c functions as the other of the source electrode and the drain electrode of the transistor 200. The conductive layer 112c can be formed using the same material and process as those of the conductive layer 112b.

[0283] The semiconductor layer 108a can be formed using the same material in the same process as the semiconductor layer 108. Alternatively, the semiconductor layer 108 and the semiconductor layer 108a can be formed using different materials in different processes.

[0284] The conductive layer 112a is used as one of a source electrode and a drain electrode of the transistor 100, and is used as one of a source electrode and a drain electrode of the transistor 200. When the transistor 100 and the transistor 200 use the conductive layer 112a in common, the occupied area of ​​the semiconductor device can be reduced.

[0285] The conductive layer 104a serves as a gate electrode of the transistor 200. The conductive layer 104a can be formed using the same material and process as those of the conductive layer 104.

[0286] [Semiconductor device 10C] Fig. 10D A circuit diagram of a semiconductor device 10C is shown. Fig.15A A top view of the semiconductor device 10C is shown. Fig. 15B It is along Fig.15A A cross-sectional view along the dot-dash line A1-A2 in FIG.

[0287] The semiconductor device 10C includes the transistor 100 and the transistor 250 . One of the source and the drain of the transistor 250 is electrically connected to one of the source and the drain of the transistor 100 .

[0288] Notice, FIG. 10D to FIG. 10H The transistor 100 shown is an n-channel transistor and the transistor 250 is a p-type transistor, but one embodiment of the present invention is not limited to this. The transistor 100 and the transistor 250 may also be both n-channel transistors or p-channel transistors. In addition, the transistor 100 may also be a p-channel transistor and the transistor 250 may also be an n-channel transistor.

[0289] The transistor 100 and the transistor 250 are both disposed on a substrate 102 .

[0290] The semiconductor device 10C includes a conductive layer 259 on a substrate 102, an insulating layer 252 on the substrate 102 and the conductive layer 259, and a semiconductor layer 253 on the insulating layer 252. In addition, an insulating layer 254 is included on the insulating layer 252 and the semiconductor layer 253, and a conductive layer 255 is included on the insulating layer 254. The semiconductor layer 253 and the conductive layer 255 have a region overlapping each other.

[0291] In addition, an insulating layer 256 is included over the insulating layer 254 and the conductive layer 255. In addition, an opening 257a is provided in the insulating layer 254 and the insulating layer 256 in a region overlapping with a portion of the semiconductor layer 253. In addition, an opening 257b is provided in the insulating layer 254 and the insulating layer 256 in a region overlapping with another portion of the semiconductor layer 253.

[0292] In addition, a conductive layer 258a is provided on the insulating layer 256 and the opening 257a, and a conductive layer 258b is provided on the insulating layer 256 and the opening 257b. The conductive layer 258a is electrically connected to the semiconductor layer 253 in the opening 257a. In addition, the conductive layer 258b is electrically connected to the semiconductor layer 253 in the opening 257b. In addition, a conductive layer 103a in contact with the conductive layer 258a is provided on the conductive layer 258a, and a conductive layer 103b in contact with the conductive layer 258b is provided on the conductive layer 258b.

[0293] The semiconductor layer 253 has a drain region 253a, a channel formation region 253b, and a source region 253c. In the semiconductor layer 253, a region overlapping with the conductive layer 255 is used as the channel formation region 253b. The drain region 253a is electrically connected to the conductive layer 258a, and the source region 253c is electrically connected to the conductive layer 258b.

[0294] Insulating layer 110 (insulating layers 110a, 110b, and 110c) is provided over insulating layer 256, conductive layer 103a, and conductive layer 103b, and conductive layer 112b is provided over insulating layer 110.

[0295] In addition, in a region overlapping with a portion of the conductive layer 258a, an opening 146 ( Fig.15A ). In addition, the semiconductor layer 108 is included inside the opening 146 .

[0296] In addition, an insulating layer 106 is included over the insulating layer 110, the conductive layer 112b, and the semiconductor layer 108, and the conductive layer 104 is included over the insulating layer 106. In addition, an insulating layer 195 is included over the insulating layer 106 and the conductive layer 104.

[0297] The conductive layer 259 is used as a back gate electrode of the transistor 250. Therefore, the conductive layer 259 preferably overlaps with the channel formation region 253b and extends beyond the end of the channel formation region 253b. In other words, the conductive layer 259 is preferably larger than the channel formation region 253b. In addition, the conductive layer 259 preferably extends beyond the end of the semiconductor layer 253. In other words, the conductive layer 259 is preferably larger than the semiconductor layer 253.

[0298] The back gate electrode is configured to sandwich the channel formation region of the semiconductor layer with the gate electrode. In addition, by changing the potential of the back gate electrode, the threshold voltage of the transistor can be changed. The potential of the back gate electrode can be the ground potential or an arbitrary potential.

[0299] The back gate electrode is formed using a conductive layer and can play the same role as the gate electrode. For example, the potential of the back gate electrode can be made the same as the potential of the gate electrode.

[0300] The back gate electrode can be formed using the same material and method as the gate electrode, source electrode, drain electrode, etc. In addition, since the gate electrode and the back gate electrode are conductive layers, they have the function of preventing the electric field generated outside the transistor from affecting the semiconductor layer forming the channel (especially the electric field shielding function against static electricity). That is, it is possible to prevent the electrical characteristics of the transistor from changing due to the influence of external electric fields such as static electricity. In addition, by providing a back gate electrode, the change in the threshold voltage of the transistor before and after the BT (Bias Temperature) stress test can be reduced. By providing a back gate electrode, the unevenness of the characteristics of the transistor is reduced, and the reliability of the semiconductor device can be improved.

[0301] The semiconductor layer 253 is used as a semiconductor layer forming a channel of the transistor 250, the insulating layer 254 is used as a gate insulating layer, and the conductive layer 255 is used as a gate electrode. In addition, the conductive layer 258a is used as a drain electrode of the transistor 250, and the conductive layer 258b is used as a source electrode.

[0302] Similar to the transistor 100 , an OS transistor can also be used as the transistor 250 .

[0303] Here, the semiconductor layer 108 and the semiconductor layer 253 may be made of the same material or different materials. The structures of the semiconductor layer 108 and the semiconductor layer 253 can refer to the description of the semiconductor layer 108 and the semiconductor layer 108 a in the semiconductor device 10 .

[0304] Alternatively, as the transistor 250 , a transistor (Si transistor) in which a channel formation region is formed using silicon may be used.

[0305] Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor including LTPS in a semiconductor layer (hereinafter also referred to as LTPS transistor) can be used. LTPS transistors have high field effect mobility and good frequency characteristics.

[0306] The transistor 100 includes a conductive layer 258a and a conductive layer 103a instead of the conductive layer 112a and the conductive layer 103, and the structure other than this is the same as that described above (see FIGS. 1 and 2).

[0307] The conductive layer 258a is used as one of the source electrode and the drain electrode of the transistor 100 and is used as one of the source electrode and the drain electrode of the transistor 250. When the transistor 100 and the transistor 250 use the conductive layer 258a in common, the occupied area of ​​the semiconductor device can be reduced.

[0308] As shown above, transistor 100 is a vertical channel transistor. On the other hand, in transistor 250, the current flowing through the semiconductor layer flows in a lateral direction, that is, in a direction parallel or substantially parallel to the surface of substrate 102. Such a transistor may be referred to as a lateral channel transistor or a lateral channel transistor.

[0309] In this manner, the semiconductor device according to one embodiment of the present invention may include a lateral channel transistor in addition to the vertical channel transistor.

[0310] like Fig. 10E As shown, the back gate and gate of transistor 250 may also be electrically connected to each other. Fig.10F As shown, the back gate and the source or drain of the transistor 250 are electrically connected to each other. Figure 10G As shown, transistor 250 may also not include a back gate.

[0311] [Semiconductor device 10D] Fig. 10H A circuit diagram of a semiconductor device 10D is shown. Fig.16A A top view of the semiconductor device 10D is shown. Fig. 16B It is along Fig.16A A cross-sectional view along the dot-dash line A1-A2 in FIG.

[0312] The semiconductor device 10D includes the transistor 100 and the transistor 250 . The gate of the transistor 250 is electrically connected to one of the source and the drain of the transistor 100 .

[0313] The semiconductor device 10D is different from the semiconductor device 10C in that the opening 146 is provided so as to overlap with the conductive layer 255 serving as the gate electrode of the transistor 250. Therefore, in the semiconductor device 10C, the transistor 100 is provided so as to overlap on the gate electrode of the transistor 250. In the semiconductor device 10D, the opening 146 is formed by selectively removing a portion of each of the conductive layer 112b, the insulating layer 110, and the conductive layer 103 in a region overlapping with the conductive layer 255.

[0314] exist Fig.16A and Fig. 16B In the embodiment, the opening 146 is provided so as to overlap the channel formation region 253b, but the present invention is not limited thereto. The opening 146 may be provided so as not to overlap the channel formation region 253b but to overlap the conductive layer 255. In the semiconductor device 10D, the conductive layer 255 is used as a gate electrode of the transistor 250 and is used as one of a source electrode and a drain electrode of the transistor 100.

[0315] By overlapping the transistor 250 and the transistor 100 , a semiconductor device with a further reduced occupied area can be realized.

[0316] Furthermore, the semiconductor device 10D is different from the semiconductor device 10C in the structures of the opening 257 a , the opening 257 b , the conductive layer 258 a , and the conductive layer 258 b .

[0317] In the semiconductor device 10D, the opening 257a is formed in a region overlapping with the drain region 253a of the semiconductor layer 253 by selectively removing a portion of each of the insulating layer 254 and the insulating layer 110. In addition, in the semiconductor device 10D, the opening 257b is formed in a region overlapping with the source region 253c of the semiconductor layer 253 by selectively removing a portion of each of the insulating layer 254 and the insulating layer 110.

[0318] Furthermore, in the semiconductor device 10D, the conductive layer 258 a and the conductive layer 258 b are provided on the insulating layer 110 .

[0319] In the semiconductor device 10D, the conductive layers 258a and 258b can be formed simultaneously with the conductive layer 112b using the same material and the same manufacturing process. Since the conductive layers 258a and 258b and the conductive layer 112b do not need to be manufactured separately, the manufacturing process of the semiconductor device can be shortened to improve the productivity of the semiconductor device.

[0320] Furthermore, a semiconductor device according to one embodiment of the present invention includes at least one transistor and at least one capacitor, and a source or a drain of the transistor is electrically connected to one of a pair of electrodes of the capacitor. Fig.10IAn example is shown in which the source or drain of the transistor 100 is electrically connected to one electrode of the capacitor 190 .

[0321] The transistor of one embodiment of the present invention is a type of vertical transistor. Since the source electrode, semiconductor layer and drain electrode can be overlapped, the occupied area can be much smaller than that of a planar transistor. In addition, by using a p-channel Si transistor as a planar transistor and an n-channel OS transistor as a vertical transistor, a CMOS (Complementary Metal Oxide Semiconductor) circuit can be formed. In addition, by adopting this structure and overlapping the planar transistor and the vertical transistor, the occupied area of ​​the CMOS circuit can be reduced.

[0322] In the transistor of one embodiment of the present invention, the gate electrode and the channel formation region in the semiconductor layer have a good positional relationship, so the field effect mobility is suppressed from decreasing. Therefore, the driving voltage can be reduced, and the power consumption of the semiconductor device can be reduced.

[0323] The semiconductor layer in the transistor of one embodiment of the present invention includes a low resistance region between the region in contact with the drain electrode and the channel formation region, thereby making it difficult to generate a high electric field near the drain region and suppressing the generation of hot carriers, thereby suppressing transistor degradation.

[0324] This embodiment mode can be appropriately combined with other embodiment modes. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be appropriately combined.

[0325] (Implementation Method 2) In this embodiment, a method for manufacturing a display device according to one embodiment of the present invention is described with reference to Fig. 17 to Fig. 19. Note that regarding materials and formation methods of each component, parts that are the same as those described in Embodiment 1 may be omitted.

[0326] 17 to 19 show side by side the Figure 1A Shown are a cross-sectional view along the dot-dash line A1 - A2 and a cross-sectional view along the dot-dash line B1 - B2 .

[0327] Note that thin films (insulating films, semiconductor films, and conductive films, etc.) constituting semiconductor devices can be formed by sputtering, chemical vapor deposition (CVD: Chemical Vapor Deposition) method, vacuum evaporation method, pulsed laser deposition (PLD: Pulsed Laser Deposition) method, ALD method, etc. CVD methods include PECVD method and thermal CVD method, etc. In addition, as one of the thermal CVD methods, there is metal organic chemical vapor deposition (MOCVD: Metal Organic CVD) method.

[0328] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute semiconductor devices can be formed using wet deposition methods such as spin coating, dipping, spraying, inkjet, dispenser, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, or doctor knife coating.

[0329] In addition, when processing a thin film constituting a semiconductor device, photolithography or the like can be used. Alternatively, the thin film can be processed by nanoimprinting, sandblasting, lift-off, etc. In addition, an island-shaped thin film can be directly formed by a deposition method using a shielding mask such as a metal mask.

[0330] There are two typical photolithography methods. One is to form a resist mask on a thin film to be processed, process the thin film by etching, etc., and remove the resist mask. The other is to deposit a photosensitive thin film, then expose and develop it, and process the thin film into a desired shape.

[0331] In the photolithography method, as the light used for exposure, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm) or a mixture of these lights can be used. In addition, ultraviolet light, KrF laser or ArF laser, etc. can also be used. In addition, liquid immersion exposure technology can also be used for exposure. In addition, as the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays can also be used. In addition, instead of the light used for exposure, an electron beam can also be used. When extreme ultraviolet light, X-rays or electron beams are used, extremely fine processing can be performed, so it is preferred. Note that when exposure is performed by scanning with a light beam such as an electron beam, a photomask is not required.

[0332] As a method for etching the thin film, a dry etching method, a wet etching method, a sand blast method, or the like can be used.

[0333] First, a conductive layer 112a is formed on the substrate 102, and a conductive layer 103f is formed on the conductive layer 112a. Fig.17A ).

[0334] When forming a conductive film to be the conductive layer 112a and a conductive film to be the conductive layer 103f, for example, a sputtering method is preferably used. After forming a resist mask on the conductive film by a photolithography process, the conductive film is processed, thereby forming a conductive layer. The conductive film to be the conductive layer 103f can be formed after the conductive layer 112a is formed, or the conductive film to be the conductive layer 103f can be formed and processed into the conductive layer 103f before the conductive film to be the conductive layer 112a is processed to form the conductive layer 112a. Note that although the conductive layer 103 having the opening 148 can be formed at this stage, it is preferred that the conductive film to be the conductive layer 103f is only processed into a desired shape such as an island shape. Then, it is preferred to form an opening in the insulating layer 110 and then form an opening in the conductive layer 103f to form the conductive layer 103. As a result, it is easy to make the shapes of the openings of the insulating layer 110 and the conductive layer 103 consistent. In the processing of the conductive film, one or both of the wet etching method and the dry etching method can be used.

[0335] Next, an insulating film 110af to be the insulating layer 110a and an insulating film 110bf to be the insulating layer 110b are formed on the conductive layer 103f. Fig. 17B ).

[0336] For example, a silicon nitride film or an aluminum oxide film is preferably formed as the insulating film 110af. Also, for example, a silicon oxide film or a silicon oxynitride film is preferably formed as the insulating film 110bf.

[0337] When forming the insulating film 110af and the insulating film 110bf, for example, a sputtering method or a PECVD method is preferably used. After forming the insulating film 110af, it is preferable to continuously form the insulating film 110bf in a vacuum so that the surface of the insulating film 110af is not exposed to the atmosphere. By continuously forming the insulating film 110af and the insulating film 110bf, it is possible to suppress impurities from the atmosphere from adhering to the surface of the insulating film 110af. Examples of such impurities include water and organic matter.

[0338] The substrate temperature when forming the insulating film 110af and the insulating film 110bf is preferably 180° C. or higher and 450° C. or lower, more preferably 200° C. or higher and 450° C. or lower, more preferably 250° C. or higher and 450° C. or lower, more preferably 300° C. or higher and 450° C. or lower, more preferably 300° C. or higher and 400° C. or lower, and more preferably 350° C. or higher and 400° C. or lower. By setting the substrate temperature when forming the insulating film 110af and the insulating film 110bf within the above range, the release of impurities (for example, water and hydrogen) from the insulating film 110af and the insulating film 110bf themselves can be reduced, thereby suppressing the diffusion of impurities into the semiconductor layer 108. Therefore, a transistor having good electrical characteristics and high reliability can be realized.

[0339] Note that since the insulating film 110af and the insulating film 110bf are formed first and then the semiconductor layer 108 is formed, there is no concern that oxygen will be released from the semiconductor layer 108 due to heat applied when the insulating film 110af and the insulating film 110bf are formed.

[0340] After forming the insulating film 110bf, it is preferable to perform plasma treatment in an oxygen-containing atmosphere without opening it to the atmosphere (in-situ). For example, N2O plasma treatment is preferably performed. By performing such plasma treatment, oxygen can be supplied to the insulating film 110bf.

[0341] Alternatively, heat treatment may be performed after the insulating film 110af and the insulating film 110bf are formed. By performing the heat treatment, water and hydrogen can be removed from the surface and the film of the insulating film 110af and the insulating film 110bf.

[0342] The temperature of the heat treatment is preferably 150° C. or higher and lower than the strain point of the substrate, more preferably 200° C. or higher and 450° C. or lower, more preferably 250° C. or higher and 450° C. or lower, more preferably 300° C. or higher and 450° C. or lower, more preferably 300° C. or higher and 400° C. or lower, and more preferably 350° C. or higher and 400° C. or lower. The heat treatment may be performed in an atmosphere containing one or more of a noble gas, nitrogen, and oxygen. As a nitrogen-containing atmosphere or an oxygen-containing atmosphere, dry air (CDA: Clean Dry Air) may also be used. Note that the content of hydrogen or oxygen in the atmosphere is preferably as small as possible. As the atmosphere, a high-purity gas having a dew point of -60° C. or lower, preferably -100° C. or lower is preferably used. By using an atmosphere containing as little hydrogen, water, or the like as possible, it is possible to prevent hydrogen, water, or the like from being absorbed by the insulating film 110af and the insulating film 110bf as much as possible. The heat treatment may be performed using an oven, a rapid thermal annealing (RTA: Rapid Thermal Annealing) device, or the like. By using an RTA device, the heat treatment time may be shortened.

[0343] Next, it is preferred that a metal oxide layer 149 ( Fig. 17C ). By forming the metal oxide layer 149, oxygen can be supplied to the insulating film 110bf.

[0344] There is no limitation on the conductivity of the metal oxide layer 149. The metal oxide layer 149 may be made of at least one of an insulating film, a semiconductor film, and a conductive film. The metal oxide layer 149 may be made of, for example, aluminum oxide, hafnium oxide, hafnium aluminate, indium oxide, indium tin oxide (ITO), or indium tin oxide containing silicon (ITSO).

[0345] As the metal oxide layer 149, an oxide material containing one or more elements that are the same as those of the semiconductor layer 108 is preferably used. In particular, an oxide semiconductor material that can be used for the semiconductor layer 108 is preferably used. For example, IGZO is preferably used for both the metal oxide layer 149 and the semiconductor layer 108.

[0346] When forming the metal oxide layer 149, the higher the ratio of the oxygen flow rate introduced into the processing chamber of the deposition device to the total flow rate of the deposition gas (oxygen flow rate ratio) or the oxygen partial pressure in the processing chamber, the greater the amount of oxygen supplied to the insulating film 110bf. The oxygen flow rate ratio or the oxygen partial pressure is, for example, 50% or more and 100% or less, preferably 65% ​​or more and 100% or less, more preferably 80% or more and 100% or less, and further preferably 90% or more and 100% or less. In particular, it is preferred to set the oxygen flow rate ratio to 100% to make the oxygen partial pressure as close to 100% as possible.

[0347] Thus, by forming the metal oxide layer 149 by sputtering in an oxygen-containing atmosphere, oxygen can be supplied to the insulating film 110bf while preventing oxygen from being separated from the insulating film 110bf when the metal oxide layer 149 is formed. As a result, a large amount of oxygen can be enclosed in the insulating film 110bf. Furthermore, a large amount of oxygen can be supplied to the semiconductor layer 108 by the subsequent heat treatment. As a result, oxygen vacancies and V in the semiconductor layer 108 can be reduced. O H, and a transistor with good electrical characteristics and high reliability can be realized.

[0348] It is preferable to perform heat treatment after forming the metal oxide layer 149. The heat treatment can be referred to the above description, so detailed description is omitted. By performing heat treatment after forming the metal oxide layer 149, oxygen can be effectively supplied from the metal oxide layer 149 to the insulating film 110bf.

[0349] After the metal oxide layer 149 is formed or after the above-mentioned heat treatment, oxygen may also be supplied to the insulating film 110bf through the metal oxide layer 149. As a method for supplying oxygen, for example, an ion implantation method, an ion doping method, a plasma immersion ion implantation method, or a plasma treatment may be used. In the plasma treatment of the method for manufacturing a semiconductor device according to one embodiment of the present invention, an apparatus for plasma-forming an oxygen gas with a high-frequency power may be appropriately used. As an apparatus for plasma-forming a gas with a high-frequency power, for example, a plasma etching apparatus and a plasma ashing apparatus may be cited.

[0350] Next, the metal oxide layer 149 is removed.

[0351] Although there is no particular limitation on the method for removing the metal oxide layer 149, a wet etching method can be appropriately used. By using the wet etching method, it is possible to suppress the insulating film 110bf from being etched when removing the metal oxide layer 149. Therefore, it is possible to suppress the thickness of the insulating film 110bf from being reduced, and the thickness of the insulating layer 110b can be made uniform.

[0352] Note that the oxygen supply treatment of the insulating film 110bf is not limited to the above method. For example, oxygen radicals, oxygen atoms, oxygen atomic ions or oxygen molecular ions can be supplied to the insulating film 110bf by ion doping, ion implantation or plasma treatment. In addition, after a film for inhibiting oxygen detachment is formed on the insulating film 110bf, oxygen can be supplied to the insulating film 110bf through the film. It is preferred to remove the film after supplying oxygen. As the above-mentioned film for inhibiting oxygen detachment, a conductive film or semiconductor film containing one or more of indium, zinc, gallium, tin, aluminum, chromium, tantalum, titanium, molybdenum, nickel, iron, cobalt and tungsten can be used.

[0353] Next, an insulating film 110cf (which will become the insulating layer 110c) is formed on the insulating film 110bf. Fig.17D Since the formation of the insulating film 110cf can refer to the description of the formation of the insulating film 110af, detailed description is omitted. Note that the deposition conditions of the insulating film 110af and the insulating film 110cf may be the same or different.

[0354] In addition, in manufacturing FIG. 5A to FIG. 5C In the case of the transistor 100B shown in the figure, an insulating film to be the insulating layer 110d is further formed on the insulating film 110cf.

[0355] For example, a silicon nitride film or an aluminum oxide film is preferably formed as the insulating film 110cf. Also, for example, a silicon nitride film is preferably formed as the insulating film 110df (not shown) to be the insulating layer 110d.

[0356] As described above, the insulating layer 110 d includes a region containing more hydrogen than the insulating layer 110 c .

[0357] The flow rate ratio of NH3 gas in the deposition gas of the insulating film 110df is preferably higher than that of the deposition gas of the insulating film 110cf. The deposition gas of the insulating film 110cf may not use NH3 gas. By performing deposition under the condition that the ratio of the flow rate of NH3 gas to the total flow rate of the deposition gas is high, the hydrogen content of the insulating film 110df can be increased. As a result, the amount of hydrogen released by heating in the insulating layer 110d can be increased. In addition, the amount of hydrogen released by heating in the insulating layer 110c can be reduced.

[0358] Furthermore, by making the deposition conditions of the insulating film 110cf and the insulating film 110df different, the amount of hydrogen released by heating in the insulating layer 110d can be adjusted. Specifically, the deposition conditions of the insulating film 110cf and the insulating film 110df can be made different by making one or more of the deposition power (deposition power density), deposition pressure, type of deposition gas, deposition gas flow ratio, deposition temperature, and distance between the substrate and the electrode. For example, when the deposition power density of the insulating film 110df is lower than the deposition power density of the insulating film 110cf, the hydrogen content of the insulating film 110df can be made greater than the hydrogen content of the insulating film 110cf. Thus, the amount of hydrogen released by heating in the insulating layer 110d can be increased.

[0359] When forming the insulating film 110cf and the insulating film 110df, for example, sputtering or PECVD is preferably used. In particular, PECVD is preferred because it allows both a film with a low hydrogen content and a film with a high hydrogen content to be easily formed.

[0360] After forming the insulating film 110cf, the insulating film 110df is preferably formed in a vacuum without exposing the surface of the insulating film 110cf to the atmosphere. By forming the insulating film 110cf and the insulating film 110df in succession, it is possible to suppress the adhesion of impurities from the atmosphere to the surface of the insulating film 110cf.

[0361] The substrate temperature when forming the insulating film 110cf and the insulating film 110df is preferably 180° C. or higher and 450° C. or lower, more preferably 200° C. or higher and 450° C. or lower, more preferably 250° C. or higher and 450° C. or lower, more preferably 300° C. or higher and 450° C. or lower, more preferably 300° C. or higher and 400° C. or lower, and more preferably 350° C. or higher and 400° C. or lower. By setting the substrate temperature when forming the insulating film 110cf and the insulating film 110df to be within the above range, the release of impurities (for example, water and hydrogen) from the insulating film 110cf and the insulating film 110df themselves can be reduced, thereby suppressing the diffusion of impurities into the semiconductor layer 108. Therefore, a transistor having good electrical characteristics and high reliability can be realized.

[0362] Next, a conductive film 112f (which will become the conductive layer 112b) is formed on the insulating film 110cf. Fig.18A ) For example, when forming the conductive film 112f, a sputtering method is preferably used.

[0363] Next, a conductive layer 112b including an opening 143 is formed. This embodiment shows the following example: Fig.18B As shown, the conductive film 112f is processed into a conductive layer 112B of a desired shape such as an island shape, and then Fig. 18C As shown in the figure, the opening 143 is provided in the conductive layer 112b, thereby forming the conductive layer 112b. Thus, the opening 141 and the opening 148 can be formed using the resist mask for forming the opening 143. In addition, the process of forming the opening 143 and the process of forming the opening 141 and the opening 148 can be performed continuously. Thus, it is easy to make the shapes of the openings of the conductive layer 112b, the insulating layer 110, and the conductive layer 103 consistent. On the other hand, the opening 143 can be provided in the conductive film 112f and then processed into a desired shape to form the conductive layer 112b.

[0364] When processing the conductive film 112f (or forming the conductive layer 112B and forming the conductive layer 112b), one or both of a wet etching method and a dry etching method can be used. In particular, when forming the opening 143, a wet etching method is preferably used.

[0365] Next, the conductive layer 103 and the insulating layer 110 (insulating layers 110a, 110b, 110c) are formed by providing openings 141 in the insulating films 110af, 110bf, and 110cf and providing openings 148 in the conductive layer 103f. Fig. 18C Here, the opening 141 and the opening 148 are provided at positions overlapping with the opening 143 of the conductive layer 112b. By providing the opening 141 and the opening 148, the region of the conductive layer 112a overlapping with the openings 141, 143, and 148 can be exposed.

[0366] One or both of wet etching and dry etching can be used when forming the openings 141 and 148. For example, by forming both the openings 141 and 148 by dry etching, the surfaces of the conductive layer 103 and the insulating layer 110 in the openings can be aligned (steps can be reduced), which is preferred.

[0367] As described above, the opening 141 and the opening 148 can be formed using, for example, a resist mask used for forming the opening 143. Specifically, a resist mask is formed on the conductive layer 112B, and a portion of the conductive layer 112B is removed using the resist mask to form the opening 143, and a portion of each of the insulating films 110af, 110bf, and 110cf is removed using the resist mask to form the opening 141, and a portion of the conductive layer 103f is removed to form the opening 148. Note that one or both of the opening 141 and the opening 148 may be formed using a resist mask different from the resist mask used for forming the opening 143.

[0368] Next, a metal oxide film 108f ( 108f ) to be the semiconductor layer 108 is formed so as to cover the openings 141 , 143 , and 148 . Fig.19A The metal oxide film 108f is provided in contact with the top surface and the side surface of the conductive layer 112b, the top surface and the side surface of the insulating layer 110, the side surface of the conductive layer 103, and the top surface of the conductive layer 112a.

[0369] In addition, the side surface of the opening 148 of the conductive layer 103 may be oxidized due to contact with the metal oxide film 108f. Depending on the material of the conductive layer 103, oxidation may occur, so that the conductivity of the conductive layer 103 decreases. Since the conductive layer 103 and the metal oxide film 108f may not be electrically connected, the side surface of the opening 148 of the conductive layer 103 may also be oxidized. For example, an oxide of the conductive layer 103 may exist between the conductive layer 103 and the metal oxide film 108f.

[0370] The metal oxide film 108f is preferably formed with as uniform a thickness as possible on the side surfaces of the opening 148 of the conductive layer 103, the side surfaces of the opening 141 of the insulating layer 110, and the side surfaces of the opening 143 of the conductive layer 112b. The metal oxide film 108f can be deposited by, for example, sputtering or ALD.

[0371] The metal oxide film 108f is preferably formed by a sputtering method using a metal oxide target.

[0372] The metal oxide film 108f is preferably a dense film with as few defects as possible. The metal oxide film 108f is preferably a high-purity film in which impurities including hydrogen elements are reduced as much as possible. In particular, as the metal oxide film 108f, a crystalline metal oxide film is preferably used.

[0373] When the metal oxide film 108f is formed, an oxygen gas is preferably used. When the metal oxide film 108f is formed using an oxygen gas, oxygen can be appropriately supplied to the insulating layer 110. For example, when an oxide is used for the insulating layer 110b, oxygen can be appropriately supplied to the insulating layer 110b.

[0374] By supplying oxygen to the insulating layer 110 b, oxygen can be supplied to the semiconductor layer 108 in a subsequent step, thereby reducing oxygen vacancies in the semiconductor layer 108 and V O H.

[0375] When the metal oxide film 108f is deposited, oxygen gas and an inert gas (e.g., helium gas, argon gas, xenon gas, etc.) may be mixed. Note that, when the metal oxide film 108f is deposited, the ratio of the flow rate of the oxygen gas to the total flow rate of the deposition gas (oxygen flow rate ratio) is higher, the crystallinity of the metal oxide film 108f can be higher, and a transistor with high reliability can be realized. On the other hand, the lower the oxygen flow rate ratio is, the lower the crystallinity of the metal oxide film 108f is, and a transistor with a large on-state current can be realized.

[0376] When the substrate temperature is high when the metal oxide film 108f is formed, a metal oxide film with higher crystallinity and higher density can be formed. On the other hand, when the substrate temperature is low, a metal oxide film with lower crystallinity and higher conductivity can be formed.

[0377] The substrate temperature when forming the metal oxide film 108f is preferably room temperature or higher and 250°C or lower, more preferably room temperature or higher and 200°C or lower, and further preferably room temperature or higher and 140°C or lower. For example, the substrate temperature is preferably room temperature or higher and 140°C or lower, thereby improving productivity. By depositing the metal oxide film 108f at room temperature or without heating the substrate, crystallinity can be reduced.

[0378] When using the ALD method, it is preferred to use a deposition method such as a thermal ALD method or PEALD (Plasma Enhanced ALD). The thermal ALD method is preferred because it has extremely high step coverage. In addition, the PEALD method is preferred because it not only has high step coverage but also allows low-temperature deposition.

[0379] The metal oxide film 108f can be deposited by, for example, an ALD method using a precursor including constituent metal elements and an oxidant.

[0380] For example, when depositing In-Ga-Zn oxide, three precursors including a precursor containing indium, a precursor containing gallium, and a precursor containing zinc may be used. Alternatively, two precursors including a precursor containing indium and a precursor containing gallium and zinc may be used.

[0381] Examples of the precursor containing indium include triethylindium, tris(2,2,6,6-tetramethyl-3,5-heptanedione)indium, cyclopentadienylindium, indium(III) chloride, and (3-(dimethylamino)propyl)dimethylindium.

[0382] Examples of the precursor containing gallium include trimethylgallium, triethylgallium, tris(dimethylamide)gallium(III), gallium(III) acetylacetonate, tris(2,2,6,6-tetramethyl-3,5-heptanedione)gallium, dimethylgallium chloride, diethylgallium chloride, and gallium(III) chloride.

[0383] Examples of the precursor containing zinc include dimethyl zinc, diethyl zinc, bis(2,2,6,6-tetramethyl-3,5-heptanedione) zinc, and zinc chloride.

[0384] Examples of the oxidizing agent include ozone, oxygen, and water.

[0385] As a method for controlling the composition of the obtained film, the flow ratio of the source gas, the flow time of the source gas, the flow order of the source gas, etc. can be exemplified. In addition, by adjusting these, a film whose composition changes continuously can be deposited. In addition, films with different compositions can also be deposited continuously.

[0386] Before depositing the metal oxide film 108f, it is preferred to perform at least one of a treatment for removing water, hydrogen, organic matter, etc. adsorbed on the surface of the insulating layer 110 and a treatment for supplying oxygen to the insulating layer 110. For example, a heat treatment may be performed at a temperature of 70°C to 200°C in a reduced pressure atmosphere. Alternatively, a plasma treatment may be performed in an oxygen-containing atmosphere. Alternatively, oxygen may be supplied to the insulating layer 110 by performing a plasma treatment in an atmosphere containing an oxidizing gas such as nitrous oxide (N2O). When a plasma treatment containing nitrous oxide gas is performed, organic matter on the surface of the insulating layer 110 can be appropriately removed and oxygen can be supplied to the insulating layer 110. Preferably, after such a treatment, the metal oxide film 108f is continuously deposited in a manner that does not expose the surface of the insulating layer 110 to the atmosphere.

[0387] Note that in the case where the semiconductor layer 108 has a stacked-layer structure, it is preferable that, after depositing a metal oxide film of a lower layer, an upper metal oxide film is continuously deposited without exposing the surface thereof to the atmosphere.

[0388] In addition, when the semiconductor layer 108 has a stacked structure, all layers constituting the semiconductor layer 108 may be formed using the same deposition method (e.g., sputtering or ALD), or different deposition methods may be used for each layer. For example, the first metal oxide layer may be deposited using the sputtering method, and the second metal oxide layer may be deposited using the ALD method.

[0389] Next, the metal oxide film 108f is processed into an island shape to form a semiconductor layer 108 ( Fig.19B ).

[0390] The semiconductor layer 108 can be formed by one or both of a wet etching method and a dry etching method, for example, preferably by a wet etching method. At this time, sometimes a portion of the conductive layer 112b in a region that does not overlap with the semiconductor layer 108 is etched to reduce the thickness. Similarly, sometimes a portion of the insulating layer 110 in a region that does not overlap with both the semiconductor layer 108 and the conductive layer 112b is etched to reduce the thickness. For example, sometimes the insulating layer 110c in the insulating layer 110 disappears due to etching, exposing the surface of the insulating layer 110b. Note that in the etching of the metal oxide film 108f, by using a material with a high selectivity as the insulating layer 110c, the thickness of the insulating layer 110c can be suppressed from being reduced.

[0391] It is preferable to perform heat treatment after the metal oxide film 108f is deposited or after the metal oxide film 108f is processed into the semiconductor layer 108. By heat treatment, hydrogen or water contained in the metal oxide film 108f or the semiconductor layer 108 or adsorbed on the surface of the metal oxide film 108f or the semiconductor layer 108 can be removed. In addition, by heat treatment, the film quality of the metal oxide film 108f or the semiconductor layer 108 is sometimes improved (for example, defects are reduced or crystallinity is improved). It is preferable to perform heat treatment before processing the semiconductor layer 108.

[0392] It is preferred that oxygen is supplied from the insulating layer 110b to at least a portion of the metal oxide film 108f or at least a portion of the semiconductor layer 108 by heat treatment. The region in contact with the insulating layer 110b in the semiconductor layer 108 and its vicinity are used as a channel formation region. By supplying oxygen to this region, oxygen vacancies in the channel formation region can be reduced to reduce the carrier concentration. In other words, the channel formation region can be made into an i-type (intrinsic) or substantially i-type region. Thus, stable electrical characteristics can be given to the transistor.

[0393] In addition, during the above-mentioned heat treatment or other heat treatment in the process, the conductive layer 103 may extract oxygen contained in the semiconductor layer 108 to form oxygen vacancies in the semiconductor layer 108. When impurities such as hydrogen enter the oxygen vacancies, the impurities are used as donors to easily increase the carrier concentration. Therefore, the region in contact with the conductive layer 103 in the semiconductor layer 108 and its vicinity can be made into a low resistance region.

[0394] Alternatively, hydrogen may be supplied from the conductive layer 103 to a portion of the metal oxide film 108f or the semiconductor layer 108. This is preferred because it is easy to reduce the resistance of a region in the semiconductor layer 108 that is in contact with the conductive layer 103 and its vicinity. For example, hydrogen is supplied from the conductive layer 103 to a portion in contact with the metal oxide film 108f or the semiconductor layer 108. In addition, during the heat treatment in the process, the supply of hydrogen from the conductive layer 103 to the metal oxide film 108f or the semiconductor layer 108 is sometimes promoted.

[0395] Regarding the heat treatment, the above description may be referred to, and thus detailed description thereof will be omitted.

[0396] Note that this heat treatment is not necessarily required. It is also possible not to perform heat treatment in this process and use the heat treatment performed in a later process as the heat treatment in this process. Sometimes, a process at a high temperature in a later process (for example, a deposition process) can be used as the heat treatment in this process.

[0397] Next, the insulating layer 106 is formed so as to cover the semiconductor layer 108, the conductive layer 112b, and the insulating layer 110. Fig.19C ) The insulating layer 106 is preferably formed by, for example, a PECVD method or an ALD method.

[0398] When an oxide semiconductor is used for the semiconductor layer 108, the insulating layer 106 is preferably used as a barrier film for suppressing diffusion of oxygen. By providing the insulating layer 106 with a function of suppressing diffusion of oxygen, it is possible to suppress diffusion of oxygen from the upper side of the insulating layer 106 to the conductive layer 104 and oxidation of the conductive layer 104. As a result, a transistor having good electrical characteristics and high reliability can be achieved.

[0399] Note that in this specification, etc., a barrier film refers to a film having barrier properties. For example, an insulating layer having barrier properties may be referred to as a barrier insulating layer. In this specification, etc., barrier properties refer to one or both of a function of suppressing diffusion of a corresponding substance (also referred to as low permeability) and a function of capturing or fixing (also referred to as gettering) a corresponding substance.

[0400] By raising the temperature when forming the insulating layer 106 used as a gate insulating layer, an insulating layer with fewer defects can be formed. However, when the temperature when forming the insulating layer 106 is high, oxygen is released from the semiconductor layer 108, and oxygen vacancies in the semiconductor layer 108 and V OH increases. The substrate temperature when forming the insulating layer 106 is preferably 180° C. to 450° C., more preferably 200° C. to 450° C., more preferably 250° C. to 450° C., more preferably 300° C. to 450° C., more preferably 300° C. to 400° C. By setting the substrate temperature when forming the insulating layer 106 within the above range, it is possible to reduce defects in the insulating layer 106 while suppressing the release of oxygen from the semiconductor layer 108. Therefore, a transistor having good electrical characteristics and high reliability can be realized.

[0401] The surface of the semiconductor layer 108 may be subjected to plasma treatment before forming the insulating layer 106. By this plasma treatment, impurities such as water adsorbed on the surface of the semiconductor layer 108 can be reduced. Therefore, impurities in the interface between the semiconductor layer 108 and the insulating layer 106 can be reduced, so a transistor with high reliability can be realized. In particular, it is preferable to perform plasma treatment when the surface of the semiconductor layer 108 is exposed to the atmosphere between the formation of the semiconductor layer 108 and the formation of the insulating layer 106. The plasma treatment can be performed, for example, in an atmosphere of oxygen, ozone, nitrogen, nitrous oxide, argon, or the like. The plasma treatment and the deposition of the insulating layer 106 are preferably performed continuously without being exposed to the atmosphere.

[0402] In addition, when a film containing a large amount of oxygen is used as the insulating layer 106, oxygen can be supplied from the insulating layer 106 to the semiconductor layer 108, which is preferable. In addition, it is more preferable to use a film that releases oxygen by heating as the insulating layer 106. Since the insulating layer 106 releases oxygen due to heat applied in the manufacturing process of the transistor, oxygen can be supplied to the semiconductor layer 108. By supplying oxygen from the insulating layer 106 to the semiconductor layer 108, especially to the channel formation region of the semiconductor layer 108, oxygen vacancies in the semiconductor layer 108 can be reduced, and a transistor with good electrical characteristics and high reliability can be realized.

[0403] Next, a conductive layer 104 is formed on the insulating layer 106 ( Fig.19C The conductive film to be the conductive layer 104 is preferably formed by, for example, a sputtering method, a thermal CVD method (including an MOCVD method), or an ALD method. A resist mask is formed on the conductive film by a photolithography process, and then the conductive film is processed to form an island-shaped conductive layer 104 serving as a gate electrode.

[0404] Through the above steps, the semiconductor device according to one embodiment of the present invention can be manufactured.

[0405] This embodiment mode can be combined with other embodiment modes as appropriate.

[0406] (Implementation method 3) In this embodiment, refer to Fig. 20A display device according to one embodiment of the present invention is described through FIG. 29 .

[0407] The display device of this embodiment mode may be a high-resolution display device or a large display device. Therefore, for example, the display device of this embodiment mode may be used as a display portion of the following devices: electronic devices with a large screen such as television devices, desktop or notebook personal computers, displays for computers, etc., digital signage, large-scale game machines such as pinball machines, etc.; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game machines; portable information terminals; and sound reproduction devices.

[0408] In addition, the display device of this embodiment can be a high-definition display device. Therefore, for example, the display device of this embodiment can be used as a display unit of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, and a display unit of wearable devices that can be worn on the head such as VR devices such as head-mounted displays (HMDs) and glasses-type AR devices.

[0409] A semiconductor device of one embodiment of the present invention can be used in a display device or a module including the display device. As a module including the display device, there can be cited a module in which the display device is equipped with a connector such as a flexible printed circuit (Flexible printed circuit, hereinafter referred to as FPC) or TCP (Tape Carrier Package), a module in which an integrated circuit (IC) is installed by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc.

[0410] The display device of this embodiment may also have a touch panel function. For example, various detection elements (also referred to as sensor elements) that can detect the approach or contact of a detection object such as a finger may be used as the display device.

[0411] Examples of the sensor type include an electrostatic capacitance type, a resistance film type, a surface acoustic wave type, an infrared type, an optical type, and a pressure-sensitive type.

[0412] As electrostatic capacitance, for example, there are surface electrostatic capacitance and projected electrostatic capacitance. In addition, as projected electrostatic capacitance, for example, there are self-capacitance and mutual capacitance. It is preferable to use the mutual capacitance because multi-point sensing can be performed simultaneously.

[0413] Examples of touch panels include out-cell, on-cell, and in-cell types. Note that an in-cell touch panel has a structure in which electrodes constituting a detection element are provided on one or both of a substrate supporting a display element and a counter substrate.

[0414] [Display device 50A] Fig. 20 It is a perspective view of the display device 50A.

[0415] The display device 50A has a structure in which a substrate 152 and a substrate 151 are bonded together. Fig. 20 In FIG. 1 , the substrate 152 is indicated by a dotted line.

[0416] The display device 50A includes a display portion 162 , a connection portion 140 , a circuit portion 164 , a conductive layer 165 , and the like. Fig. 20 The example in which the display device 50A is mounted with the IC 173 and the FPC 172 is shown. Fig. 20 The structure shown is called a display module including the display device 50A, IC and FPC.

[0417] The connection portion 140 is disposed outside the display portion 162. The connection portion 140 may be disposed along one side or multiple sides of the display portion 162. There may also be one or more connection portions 140. Fig. 20 The example in which the connection part 140 is provided so as to surround the four sides of the display part is shown. In the connection part 140, the common electrode of the display element is electrically connected to the conductive layer, and a potential can be supplied to the common electrode.

[0418] The circuit portion 164 includes, for example, a scanning line driving circuit (also referred to as a gate driver). Alternatively, the circuit portion 164 may include both a scanning line driving circuit and a signal line driving circuit (also referred to as a source driver).

[0419] The conductive layer 165 has a function of supplying signals and power to the display portion 162 and the circuit portion 164. The signals and power are input to the conductive layer 165 from the outside through the FPC 172 or from the IC 173.

[0420] Fig. 20 An example of providing IC 173 on substrate 151 by COG method or COF method is shown. As IC 173, for example, an IC including one or both of a scanning line driving circuit and a signal line driving circuit can be used. Note that the display device 50A and the display module do not necessarily have to be provided with an IC. In addition, the IC can also be mounted on an FPC by COF method or the like.

[0421] The semiconductor device according to one embodiment of the present invention can be used for, for example, one or both of the display portion 162 and the circuit portion 164 of the display device 50A.

[0422] For example, when a semiconductor device of one embodiment of the present invention is used in a pixel circuit of a display device, the area occupied by the pixel circuit can be reduced to realize a high-definition display device. In addition, for example, when a semiconductor device of one embodiment of the present invention is used in a drive circuit of a display device (for example, one or both of a gate line drive circuit and a source line drive circuit), the area occupied by the drive circuit can be reduced to realize a display device with a narrow frame. In addition, a semiconductor device of one embodiment of the present invention has good electrical characteristics, and by using the semiconductor device in a display device, the reliability of the display device can be improved.

[0423] The display unit 162 is an image display region in the display device 50A, and includes a plurality of pixels 201 arranged periodically. Fig. 20 An enlarged view of one pixel 201 is shown in FIG.

[0424] There is no particular limitation on the arrangement of pixels in the display device of this embodiment, and various methods can be used. Examples of pixel arrangements include stripe arrangement, S-stripe arrangement, matrix arrangement, Delta arrangement, Bayer arrangement, and Pentile arrangement.

[0425] Fig. 20 The pixel 201 shown includes a sub-pixel 11R that emits red light, a sub-pixel 11G that emits green light, and a sub-pixel 11B that emits blue light.

[0426] Each of the sub-pixels 11R, 11G, and 11B includes a display element and a circuit for controlling driving of the display element.

[0427] Various elements can be used as display elements, for example, liquid crystal elements and light-emitting elements. In addition, MEMS (Micro Electro Mechanical Systems) elements of shutter mode or light interference mode, display elements using microcapsule mode, electrophoresis mode, electrowetting mode or electronic powder fluid (registered trademark) mode, etc. can also be used. In addition, QLED (Quantum-dot LED) using light source and color conversion technology using quantum dot materials can also be used.

[0428] Examples of display devices using a liquid crystal element include a transmissive liquid crystal display device, a reflective liquid crystal display device, and a semi-transmissive liquid crystal display device.

[0429] Examples of modes that can be used in a display device using a liquid crystal element include a vertical alignment (VA) mode, an FFS (Fringe Field Switching) mode, an IPS (In-Plane-Switching) mode, a TN (Twisted Nematic) mode, an ASM (Axially Symmetric aligned Micro-cell) mode, an OCB (Optically Compensated Birefringence) mode, an FLC (Ferroelectric Liquid Crystal) mode, an AFLC (Anti Ferroelectric Liquid Crystal) mode, an ECB (Electrically Controlled Birefringence) mode, and a guest-host mode. Examples of the VA mode include an MVA (Multi-Domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, and an ASV (Advanced SuperView) mode.

[0430] As liquid crystal materials that can be used for liquid crystal elements, for example, thermotropic liquid crystals, low molecular liquid crystals, polymer liquid crystals, polymer dispersed liquid crystals (PDLC: Polymer Dispersed Liquid Crystal: polymer dispersed liquid crystals), polymer network liquid crystals (PNLC: Polymer Network Liquid Crystal), ferroelectric liquid crystals and antiferroelectric liquid crystals can be cited. These liquid crystal materials present cholesteric phases, smectic phases, cubic phases, chiral nematic phases, isotropic phases, blue phases, etc. depending on the conditions. In addition, as liquid crystal materials, any of positive liquid crystals and negative liquid crystals can be used, and can be selected according to the mode or design used.

[0431] As the light emitting element, for example, there can be mentioned self-luminous light emitting elements such as LED, OLED (Organic LED), semiconductor laser, etc. As the LED, for example, a small LED, a micro LED, etc. can be used.

[0432] Examples of the light-emitting substance contained in the light-emitting element include substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescent materials), substances that exhibit thermally activated delayed fluorescence (TADF materials), and inorganic compounds (quantum dot materials, etc.).

[0433] The light emitting element may emit light of infrared, red, green, blue, cyan, magenta, yellow or white, etc. In addition, when the light emitting element has a microcavity structure, the color purity can be further improved.

[0434] Of a pair of electrodes included in the light emitting element, one electrode is used as an anode and the other electrode is used as a cathode.

[0435] A display device according to one embodiment of the present invention may also adopt any of the following structures: a top emission type that emits light in a direction opposite to a substrate on which a light-emitting element is formed, a bottom emission type that emits light to one side of a substrate on which a light-emitting element is formed, or a dual emission type that emits light to both sides.

[0436] Fig.21A An example of a cross section of a portion of the region including the FPC 172 , a portion of the circuit portion 164 , a portion of the display portion 162 , a portion of the connection portion 140 , and a portion of the region including the end portion of the display device 50A is shown.

[0437] Fig.21A The display device 50A shown includes transistors 205D, 205R, 205G, 205B, light-emitting elements 130R, 130G, 130B, etc. between substrates 151 and 152. The light-emitting element 130R is a display element included in the sub-pixel 11R that emits red light, the light-emitting element 130G is a display element included in the sub-pixel 11G that emits green light, and the light-emitting element 130B is a display element included in the sub-pixel 11B that emits blue light.

[0438] The display device 50A adopts an SBS structure. In the SBS structure, the material and structure of each light emitting element can be optimized separately, the degree of freedom in selecting materials and structures is increased, and it becomes easy to improve brightness and reliability.

[0439] The display device 50A adopts a top emission type. In the top emission type, transistors and the like can be arranged so as to overlap with the light emitting region of the light emitting element, so that the aperture ratio of the pixel can be further increased compared with the bottom emission type.

[0440] The transistors 205D, 205R, 205G, and 205B are all formed on the substrate 151. These transistors can be manufactured using the same material and the same process.

[0441] In this embodiment, an example of using OS transistors as transistors 205D, 205R, 205G, and 205B is shown. As transistors 205D, 205R, 205G, and 205B, transistors of one embodiment of the present invention can be used. That is, in the display device 50A, both the display unit 162 and the circuit unit 164 include transistors of one embodiment of the present invention. By using a transistor of one embodiment of the present invention in the display unit 162, the pixel size can be reduced and high definition can be achieved. In addition, by using a transistor of one embodiment of the present invention in the circuit unit 164, the area occupied by the circuit unit 164 can be reduced and a narrow frame can be achieved. For the transistor of one embodiment of the present invention, reference can be made to the description of the above embodiment.

[0442] Specifically, transistors 205D, 205R, 205G, and 205B all include a conductive layer 104 serving as a gate, an insulating layer 106 serving as a gate insulating layer, conductive layers 112a and 112b serving as a source and a drain, a semiconductor layer 108 containing a metal oxide, a conductive layer 103 in contact with the conductive layer 112a and the semiconductor layer 108, and an insulating layer 110 (insulating layers 110a, 110b, and 110c). Here, a plurality of layers obtained by processing the same conductive film are given the same hatching. The insulating layer 110 is located between the conductive layer 112a and the semiconductor layer 108. The insulating layer 106 is located between the conductive layer 104 and the semiconductor layer 108.

[0443] Note that the transistor included in the display device of this embodiment is not limited to the transistor of one embodiment of the present invention. For example, the transistor of one embodiment of the present invention and a transistor of another structure may be combined.

[0444] The display device of this embodiment may include, for example, any one or more of a planar transistor, a staggered transistor, and an inversely staggered transistor. The transistor included in the display device of this embodiment has any one of a top-gate structure and a bottom-gate structure. Alternatively, gate electrodes may be provided above and below the semiconductor layer forming the channel.

[0445] Furthermore, the display device of this embodiment may include a Si transistor.

[0446] When the luminous brightness of the light-emitting element included in the pixel circuit is increased, the amount of current flowing through the light-emitting element needs to be increased. To this end, it is necessary to increase the source-drain voltage of the driving transistor included in the pixel circuit. Because the source-drain withstand voltage of the OS transistor is higher than that of the Si transistor, a high voltage can be applied to the source-drain of the OS transistor. Thus, by using the OS transistor as the driving transistor included in the pixel circuit, the amount of current flowing through the light-emitting element can be increased to improve the luminous brightness of the light-emitting element.

[0447] In addition, when the transistor operates in the saturation region, the OS transistor can make the change in the source-drain current for the change in the gate-source voltage smaller than the Si transistor. Therefore, by using the OS transistor as the driving transistor included in the pixel circuit, the current flowing through the source-drain can be determined in detail according to the change in the gate-source voltage, so the amount of current flowing through the light-emitting element can be controlled. As a result, the number of grayscales of the pixel circuit can be increased.

[0448] In addition, regarding the saturation characteristics of the current flowing when the transistor operates in the saturation region, compared with the Si transistor, the OS transistor can make a stable current (saturation current) flow even if the source-drain voltage is gradually increased. Therefore, by using the OS transistor as a driving transistor, even if, for example, the current-voltage characteristics of the light-emitting element are uneven, a stable current can flow through the light-emitting element. That is, when the OS transistor operates in the saturation region, even if the source-drain voltage is changed, the source-drain current remains almost unchanged, so the light-emitting brightness of the light-emitting element can be stabilized.

[0449] The transistors included in the circuit portion 164 and the transistors included in the display portion 162 may have the same structure or different structures. The plurality of transistors included in the circuit portion 164 may have the same structure or two or more different structures. Similarly, the plurality of transistors included in the display portion 162 may have the same structure or two or more different structures.

[0450] All transistors included in the display portion 162 may be OS transistors, all transistors included in the display portion 162 may be Si transistors, some transistors included in the display portion 162 may be OS transistors and the remaining transistors may be Si transistors.

[0451] For example, by using both LTPS transistors and OS transistors in the display portion 162, a display device with low power consumption and high driving capability can be realized. In addition, a structure in which an LTPS transistor and an OS transistor are combined is sometimes referred to as LTPO. As a more preferred example, a structure in which an OS transistor is used as a transistor used as a switch for controlling conduction / non-conduction between wirings and an LTPS transistor is used as a transistor for controlling current can be cited.

[0452] For example, one of the transistors included in the display unit 162 is used as a transistor for controlling the current flowing through the light-emitting element and may also be referred to as a driving transistor. One of the source and drain of the driving transistor is electrically connected to the pixel electrode of the light-emitting element. An LTPS transistor is preferably used as the driving transistor. Thus, the current flowing through the light-emitting element in the pixel circuit can be increased.

[0453] On the other hand, one of the other transistors included in the display unit 162 is used as a switch for controlling the selection and non-selection of pixels, and may also be referred to as a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and the drain is electrically connected to the source line (signal line). The selection transistor is preferably an OS transistor. Therefore, even if the frame rate is significantly reduced (for example, below 1fps), the grayscale of the pixel can be maintained, thereby reducing power consumption by stopping the driver when displaying a static image.

[0454] An insulating layer 218 is provided to cover the transistors 205D, 205R, 205G, and 205B, and an insulating layer 235 is provided over the insulating layer 218 .

[0455] The insulating layer 218 is preferably used as a protective layer of the transistor. The insulating layer 218 is preferably made of a material that does not easily diffuse impurities such as water and hydrogen. Thus, the insulating layer 218 can be used as a barrier layer. By adopting this structure, it is possible to effectively suppress the diffusion of impurities from the outside into the transistor, thereby improving the reliability of the display device.

[0456] The insulating layer 218 preferably includes one or more inorganic insulating films. Examples of the inorganic insulating film include an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film. Specific examples of these inorganic insulating films are as described above.

[0457] The insulating layer 235 is preferably used as a planarization layer, and an organic insulating film is suitable. As materials that can be used for the organic insulating film, for example, acrylic resins, polyimide resins, epoxy resins, polyamide resins, polyimide amide resins, siloxane resins, benzocyclobutene resins, phenolic resins, and precursors of these resins can be used. In addition, the insulating layer 235 can also adopt a laminated structure of an organic insulating film and an inorganic insulating film. The outermost layer of the insulating layer 235 is preferably used as an etching protection layer. As a result, when processing the pixel electrodes 111R, 111G, 111B, etc., it is possible to suppress the formation of recesses in the insulating layer 235. Alternatively, recesses can be provided in the insulating layer 235 when processing the pixel electrodes 111R, 111G, 111B, etc.

[0458] The light emitting elements 130R, 130G, and 130B are provided on the insulating layer 235 .

[0459] The light emitting element 130R includes a pixel electrode 111R on the insulating layer 235 , an EL layer 113R on the pixel electrode 111R, and a common electrode 115 on the EL layer 113R. Fig.21A The light emitting element 130R shown emits red light (R). The EL layer 113R includes a light emitting layer that emits red light.

[0460] The light emitting element 130G includes a pixel electrode 111G on the insulating layer 235 , an EL layer 113G on the pixel electrode 111G, and a common electrode 115 on the EL layer 113G. Fig.21A The light emitting element 130G shown emits green light (G). The EL layer 113G includes a light emitting layer that emits green light.

[0461] The light-emitting element 130B includes a pixel electrode 111B on the insulating layer 235 , an EL layer 113B on the pixel electrode 111B, and a common electrode 115 on the EL layer 113B. Fig.21A The light emitting element 130B shown emits blue light (B). The EL layer 113B includes a light emitting layer that emits blue light.

[0462] Note that Fig.21A EL layers 113R, 113G, and 113B are shown as having the same thickness, but the present invention is not limited thereto. The thickness of each film of EL layers 113R, 113G, and 113B may be different. For example, it is preferable to set the thickness according to the optical path length of the light emitted by the enhanced EL layers 113R, 113G, and 113B. Thus, a microcavity structure can be realized to improve the color purity of the light emitted from each light-emitting element.

[0463] The pixel electrode 111R is electrically connected to the conductive layer 112b of the transistor 205R through an opening provided in the insulating layer 106, the insulating layer 218, and the insulating layer 235. Similarly, the pixel electrode 111G is electrically connected to the conductive layer 112b of the transistor 205G, and the pixel electrode 111B is electrically connected to the conductive layer 112b of the transistor 205B.

[0464] Each end of the pixel electrodes 111R, 111G, and 111B is covered by an insulating layer 237. The insulating layer 237 is used as a partition wall. The insulating layer 237 can be set to a single-layer structure or a stacked-layer structure using one or both of an inorganic insulating material and an organic insulating material. For example, the insulating layer 237 can use a material that can be used for the insulating layer 218 and a material that can be used for the insulating layer 235. The insulating layer 237 can electrically insulate the pixel electrode from the common electrode. In addition, the insulating layer 237 can electrically insulate the light-emitting elements adjacent to each other.

[0465] The insulating layer 237 is provided at least in the display portion 162. The insulating layer 237 may be provided not only in the display portion 162 but also in the connection portion 140 and the circuit portion 164. In addition, the insulating layer 237 may be provided so as to extend to the end portion of the display device 50A.

[0466] The common electrode 115 is a continuous film shared by the light-emitting elements 130R, 130G, and 130B. The common electrode 115 shared by the plurality of light-emitting elements is electrically connected to the conductive layer 123 provided in the connection portion 140. The conductive layer 123 is preferably formed using the same material and the same process as the pixel electrodes 111R, 111G, and 111B.

[0467] In the display device of one embodiment of the present invention, a conductive film that transmits visible light is used as the electrode on the light extraction side of the pixel electrode and the common electrode. In addition, a conductive film that reflects visible light is preferably used as the electrode on the side that does not extract light.

[0468] In addition, the electrode on the side where light is not extracted may also be a conductive film that transmits visible light. In this case, it is preferable to configure the electrode between the reflective layer and the EL layer. In other words, the light emitted by the EL layer can also be reflected by the reflective layer and extracted from the display device.

[0469] As the material for forming a pair of electrodes of the light-emitting element, metals, alloys, conductive compounds and mixtures thereof can be appropriately used. As the material, specifically, metals such as aluminum, magnesium, titanium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, indium, tin, molybdenum, tantalum, tungsten, palladium, gold, platinum, silver, yttrium and neodymium and alloys appropriately combined therewith can be cited. In addition, as the material, indium tin oxide (also referred to as In-Sn oxide, ITO), In-Si-Sn oxide (also referred to as ITSO), indium zinc oxide (In-Zn oxide) and In-W-Zn oxide can be cited. In addition, as the material, aluminum alloys (aluminum alloys) such as aluminum, nickel and lanthanum alloys (Al-Ni-La), silver and magnesium alloys and silver, palladium and copper alloys (also referred to as Ag-Pd-Cu, APC) and other silver-containing alloys can be cited. In addition, examples of the material include elements belonging to Group 1 or Group 2 of the periodic table that are not listed above (e.g., lithium, cesium, calcium, and strontium), rare earth metals such as europium and ytterbium, alloys of appropriately combined elements, and graphene.

[0470] The light-emitting element preferably adopts a microcavity resonator (microcavity) structure. Therefore, one of a pair of electrodes included in the light-emitting element preferably includes an electrode having visible light transmittance and reflectivity (semi-transmissive-semi-reflective electrode), and the other preferably includes an electrode having visible light reflectivity (reflective electrode). When the light-emitting element has a microcavity structure, the light emitted from the light-emitting layer can be resonated between the two electrodes, and the light emitted from the light-emitting element can be enhanced.

[0471] The light transmittance of the transparent electrode is 40% or more. For example, an electrode having a visible light (light with a wavelength of 400 nm or more and less than 750 nm) transmittance of 40% or more is preferably used as a transparent electrode of a light-emitting element. The reflectivity of the semi-transmissive-semi-reflective electrode to visible light is 10% or more and 95% or less, preferably 30% or more and 80% or less. The reflectivity of the reflective electrode to visible light is 40% or more and 100% or less, preferably 70% or more and 100% or less. In addition, the resistivity of these electrodes is preferably 1×10 -2 Ωcm or less.

[0472] The EL layers 113R, 113G, and 113B are all arranged in an island shape. Fig.21A In the embodiment, the ends of the adjacent EL layers 113R overlap with the ends of the EL layers 113G, the ends of the adjacent EL layers 113G overlap with the ends of the EL layers 113B, and the ends of the adjacent EL layers 113R overlap with the ends of the EL layers 113B. Fig.21AAs shown in FIG. 1 , when an island-shaped EL layer is deposited using a high-definition metal mask, the ends of adjacent EL layers may overlap each other, but the present invention is not limited to this. That is, adjacent EL layers may not overlap each other but may be separated. In addition, in a display device, there may be both overlapping portions of adjacent EL layers and separated portions of adjacent EL layers not overlapping each other.

[0473] Each of the EL layers 113R, 113G, and 113B includes at least a light-emitting layer. The light-emitting layer contains one or more light-emitting substances. As the light-emitting substance, a substance that emits light in a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red is appropriately used. In addition, as the light-emitting substance, a substance that emits near-infrared light can also be used.

[0474] Examples of the light-emitting substance include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0475] The light-emitting layer may contain one or more organic compounds (host material, auxiliary material, etc.) in addition to the light-emitting substance (guest material). As one or more organic compounds, one or both of a substance with high hole transport properties (hole transport material) and a substance with high electron transport properties (electron transport material) may be used. In addition, as one or more organic compounds, a bipolar substance (a substance with high electron transport properties and hole transport properties) or a TADF material may also be used.

[0476] For example, the light-emitting layer preferably includes a combination of a phosphorescent material, a hole transport material that easily forms an exciplex, and an electron transport material. By adopting such a structure, it is possible to efficiently obtain light emission using ExTET (Exciplex-Triplet Energy Transfer) that utilizes energy transfer from the exciplex to the luminescent substance (phosphorescent material). In addition, by selecting a combination of light that emits light with a wavelength overlapping the absorption band on the lowest energy side of the luminescent substance as the exciplex, energy transfer can be smoothed, thereby efficiently obtaining light emission. By adopting the above structure, high efficiency, low voltage drive, and long life of the light-emitting element can be achieved at the same time.

[0477] In addition to the light-emitting layer, the EL layer may include one or more of a layer containing a substance with high hole injection properties (hole injection layer), a layer containing a hole transport material (hole transport layer), a layer containing a substance with high electron blocking properties (electron blocking layer), a layer containing a substance with high electron injection properties (electron injection layer), a layer containing an electron transport material (electron transport layer), and a layer containing a substance with high hole blocking properties (hole blocking layer). In addition, the EL layer may also contain one or both of a bipolar substance and a TADF material.

[0478] The light emitting element may use a low molecular weight compound or a high molecular weight compound, and may further contain an inorganic compound. The layers constituting the light emitting element may be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet, or coating.

[0479] The light-emitting element may adopt a single structure (a structure with only one light-emitting unit) or a series structure (a structure including multiple light-emitting units). The light-emitting unit includes at least one light-emitting layer. The series structure has a structure in which multiple light-emitting units are connected in series through a charge generation layer. The charge generation layer has the function of injecting electrons into one of the two light-emitting units and injecting holes into the other when a voltage is applied between a pair of electrodes. By adopting a series structure, a light-emitting element capable of emitting light with high brightness can be realized. In addition, the series structure can improve reliability because the current required to obtain the same brightness can be reduced compared to the single structure. In addition, the series structure can also be referred to as a stacked structure.

[0480] exist Fig.21A When a tandem-structured light-emitting element is used, it is preferred that the EL layer 113R include a plurality of light-emitting units emitting red light, the EL layer 113G include a plurality of light-emitting units emitting green light, and the EL layer 113B include a plurality of light-emitting units emitting blue light.

[0481] A protective layer 131 is provided on the light emitting elements 130R, 130G, and 130B. The protective layer 131 and the substrate 152 are bonded by an adhesive layer 142. The substrate 152 is provided with a light shielding layer 117. As a seal for the light emitting element, for example, a solid sealing structure or a hollow sealing structure can be adopted. Fig.21A In the embodiment, the space between the substrate 152 and the substrate 151 is filled with the adhesive layer 142, that is, a solid sealing structure is adopted. Alternatively, a hollow sealing structure in which the space is filled with an inert gas (nitrogen or argon, etc.) can also be adopted. In this case, the adhesive layer 142 can also be arranged in a manner that does not overlap with the light-emitting element. In addition, a resin different from the adhesive layer 142 arranged in a frame shape can also be used to fill the space.

[0482] The protective layer 131 is provided at least in the display portion 162, and is preferably provided in a manner covering the entire display portion 162. The protective layer 131 is preferably provided in a manner covering the connection portion 140 and the circuit portion 164 in addition to the display portion 162. In addition, the protective layer 131 is preferably provided in a manner extending to the end of the display device 50A. On the other hand, in order to electrically connect the FPC 172 and the conductive layer 166, there is a portion in the connection portion 204 where the protective layer 131 is not provided.

[0483] By providing the protective layer 131 on the light emitting elements 130R, 130G, and 130B, the reliability of the light emitting elements can be improved.

[0484] The protective layer 131 may have a single layer structure or a stacked layer structure of two or more layers. In addition, there is no limitation on the conductivity of the protective layer 131. As the protective layer 131, at least one of an insulating film, a semiconductor film, and a conductive film may be used.

[0485] When the protective layer 131 includes an inorganic film, degradation of the light emitting element can be suppressed, such as preventing oxidation of the common electrode 115 and suppressing impurities (moisture, oxygen, etc.) from entering the light emitting element, thereby improving the reliability of the display device.

[0486] As the protective layer 131, for example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film can be used. Specific examples of these inorganic insulating films are as described above. In particular, the protective layer 131 preferably includes a nitride insulating film or a nitride oxide insulating film, and more preferably includes a nitride insulating film.

[0487] In addition, an inorganic film including ITO, In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or IGZO may be used as the protective layer 131. The inorganic film preferably has a high resistance, and specifically, the inorganic film preferably has a resistance higher than that of the common electrode 115. The inorganic film may further include nitrogen.

[0488] When light emitted from the light emitting element is extracted through the protective layer 131, the protective layer 131 preferably has high visible light transmittance. For example, ITO, IGZO, and alumina are inorganic materials with high visible light transmittance and are therefore preferred.

[0489] As the protective layer 131, for example, a stacked structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film or a stacked structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used. By using this stacked structure, impurities (water, oxygen, etc.) can be suppressed from entering the EL layer.

[0490] Furthermore, the protective layer 131 may include an organic film. For example, the protective layer 131 may include both an organic film and an inorganic film. Examples of the organic film that can be used for the protective layer 131 include an organic insulating film that can be used for the insulating layer 235 .

[0491] A connection portion 204 is provided in a region where the substrate 151 and the substrate 152 do not overlap. In the connection portion 204, the conductive layer 165 is electrically connected to the FPC 172 through the conductive layer 166 and the connection layer 242. For example, the conductive layer 165 is a conductive layer obtained by processing the same conductive film as the conductive layer 112b. For example, the conductive layer 166 is a conductive layer obtained by processing the same conductive film as the pixel electrodes 111R, 111G, and 111B. The conductive layer 166 is exposed on the top surface of the connection portion 204. Therefore, the connection portion 204 can be electrically connected to the FPC 172 through the connection layer 242.

[0492] The display device 50A is a top emission type. Light emitted by the light emitting element is emitted to the substrate 152 side. The substrate 152 is preferably made of a material with high visible light transmittance. The pixel electrodes 111R, 111G, and 111B are made of a material that reflects visible light, and the counter electrode (common electrode 115) is made of a material that transmits visible light.

[0493] A light shielding layer 117 is preferably provided on a surface of the substrate 152 on the substrate 151 side. The light shielding layer 117 can be provided between adjacent light emitting elements, in the connection portion 140, the circuit portion 164, and the like.

[0494] Alternatively, a coloring layer such as a color filter may be provided on the surface of the substrate 152 on the substrate 151 side or on the protective layer 131. When the color filter is provided so as to overlap with the light-emitting element, the color purity of light emitted from the pixel can be improved.

[0495] The coloring layer is a colored layer that selectively transmits light in a specific wavelength region and absorbs light in other wavelength regions. For example, a red (R) color filter that transmits light in a red wavelength region, a green (G) color filter that transmits light in a green wavelength region, a blue (B) color filter that transmits light in a blue wavelength region, etc. can be used. Each coloring layer can use one or more of a metal material, a resin material, a pigment, and a dye. The coloring layer is formed at a desired position using a printing method, an inkjet method, an etching method using a photolithography method, etc.

[0496] In addition, various optical components can be arranged on the outside of the substrate 152 (the surface on the opposite side of the substrate 151). As optical components, for example, polarizers, phase difference plates, light diffusion layers (diffusion films, etc.), anti-reflection layers, and light-focusing films (condensing films) can be cited. In addition, surface protective layers such as antistatic films that inhibit the adhesion of dust, water-repellent films that are not easily soiled, hard coatings that inhibit damage during use, and impact-absorbing layers can also be arranged on the outside of the substrate 152. For example, by providing a glass layer or a silicon dioxide layer (SiO x Layer), which can prevent the surface from being dirty or damaged, is preferred. In addition, DLC (diamond-like carbon), aluminum oxide (AlO x ), polyester materials or polycarbonate materials, etc. In addition, as the surface protection layer, it is preferred to use a material with high transmittance to visible light. In addition, the surface protection layer is preferably made of a material with high hardness.

[0497] Glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc. can be used for the substrate 151 and the substrate 152, respectively. A material that transmits the light is used for the substrate on the side where the light is taken out from the light-emitting element. By using a flexible material for the substrate 151 and the substrate 152, the flexibility of the display device can be improved, thereby realizing a flexible display. A polarizing plate can also be used as at least one of the substrate 151 and the substrate 152.

[0498] As the substrate 151 and the substrate 152, the following materials can be used respectively: polyester resins such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resins, acrylic resins, polyimide resins, polymethyl methacrylate resins, polycarbonate (PC) resins, polyether sulfone (PES) resins, polyamide resins (nylon, aramid, etc.), polysiloxane resins, cycloolefin resins, polystyrene resins, polyamide-imide resins, polyurethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polypropylene resins, polytetrafluoroethylene (PTFE) resins, ABS resins, and cellulose nanofibers, etc. In addition, glass having a thickness that allows flexibility can be used as at least one of the substrates 151 and 152.

[0499] When a circular polarizer is overlapped on a display device, it is preferred to use a substrate with high optical isotropy as the substrate included in the display device. The substrate with high optical isotropy has low birefringence (it can also be said that the amount of birefringence is small). As films with high optical isotropy, triacetyl cellulose (TAC, also called triacetyl cellulose) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic resin films can be cited.

[0500] As the adhesive layer 142, various curing adhesives such as light curing adhesives such as ultraviolet curing adhesives, reaction curing adhesives, heat curing adhesives, anaerobic adhesives, etc. can be used. As these adhesives, epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene-vinyl acetate) resins, etc. can be cited. In particular, it is preferred to use materials with low moisture permeability such as epoxy resins. In addition, two-liquid mixed resins can also be used. In addition, adhesive sheets, etc. can also be used.

[0501] As the connection layer 242 , an anisotropic conductive film (ACF: Anisotropic Conductive Film), anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

[0502] [Display device 50B] Fig.21B An example of a cross section of the display portion 162 of the display device 50B is shown. The display device 50B differs from the display device 50A mainly in that a light-emitting element including an EL layer 113 shared by the light-emitting elements and a coloring layer (color filter, etc.) are used in sub-pixels of respective colors. Fig.21B The structure shown can be combined with Fig.21A The region shown includes the FPC 172, the circuit portion 164, the stacked structure from the substrate 151 to the insulating layer 235 of the display portion 162, the connection portion 140, and the structure of the end portion. Note that in the description of the display device described later, the description of the same parts as the display device described previously may be omitted.

[0503] Fig.21B The display device 50B shown includes light emitting elements 130R, 130G, and 130B, a coloring layer 132R that transmits red light, a coloring layer 132G that transmits green light, a coloring layer 132B that transmits blue light, and the like.

[0504] The light emitting element 130R includes a pixel electrode 111R, an EL layer 113 on the pixel electrode 111R, and a common electrode 115 on the EL layer 113. Light emitted by the light emitting element 130R is extracted as red light to the outside of the display device 50B through the coloring layer 132R.

[0505] The light emitting element 130G includes a pixel electrode 111G, an EL layer 113 on the pixel electrode 111G, and a common electrode 115 on the EL layer 113. Light emitted by the light emitting element 130G is extracted as green light to the outside of the display device 50B through the coloring layer 132G.

[0506] The light emitting element 130B includes a pixel electrode 111B, an EL layer 113 on the pixel electrode 111B, and a common electrode 115 on the EL layer 113. Light emitted by the light emitting element 130B is extracted as blue light to the outside of the display device 50B through the coloring layer 132B.

[0507] The light emitting elements 130R, 130G, and 130B share the EL layer 113 and the common electrode 115. Compared with a structure in which each sub-pixel of each color is provided with a different EL layer, a structure in which each sub-pixel of each color shares the EL layer 113 can reduce the number of manufacturing steps.

[0508] For example, Fig.21B The light emitting elements 130R, 130G, and 130B shown emit white light. The white light emitted by the light emitting elements 130R, 130G, and 130B passes through the colored layers 132R, 132G, and 132B, thereby obtaining light of a desired color.

[0509] The white light-emitting element preferably includes two or more light-emitting layers. In the case of using two light-emitting layers to obtain white light, the light-emitting layers can be selected in such a way that the light-emitting colors of the two light-emitting layers are in a complementary color relationship. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer in a complementary color relationship, a structure in which the light-emitting element as a whole emits white light can be obtained. In addition, in the case of using three or more light-emitting layers to obtain white light, the light-emitting colors of the three or more light-emitting layers are combined to obtain a structure in which the light-emitting element as a whole emits white light.

[0510] The EL layer 113 preferably includes, for example, a light-emitting layer containing a light-emitting substance that emits blue light and a light-emitting layer containing a light-emitting substance that emits visible light having a longer wavelength than blue. The EL layer 113 preferably includes, for example, a light-emitting layer that emits yellow light and a light-emitting layer that emits blue light. Alternatively, the EL layer 113 preferably includes, for example, a light-emitting layer that emits red light, a light-emitting layer that emits green light, and a light-emitting layer that emits blue light.

[0511] The light-emitting element emitting white light preferably adopts a series structure. Specifically, it can be: a two-stage series structure including a light-emitting unit emitting yellow light and a light-emitting unit emitting blue light; a two-stage series structure including a light-emitting unit emitting red light and green light and a light-emitting unit emitting blue light; a three-stage series structure including a light-emitting unit emitting blue light, a light-emitting unit emitting yellow light, yellow-green light or green light, and a light-emitting unit emitting blue light in sequence; or a three-stage series structure including a light-emitting unit emitting blue light, a light-emitting unit emitting yellow light, yellow-green light or green light and red light, and a light-emitting unit emitting blue light in sequence, etc. For example, as the number of layers and color sequence of the light-emitting unit, there can be cited a two-stage structure in which B and Y are stacked from the anode side, a two-stage structure in which B and the light-emitting unit X are stacked, a three-stage structure in which B, Y and B are stacked, and a three-stage structure in which B, X and B are stacked. As the number of layers and color sequence of the light-emitting layer in the light-emitting unit X, there can be adopted a two-stage structure in which R and Y are stacked from the anode side, a two-stage structure in which R and G are stacked, a two-stage structure in which G and R are stacked, a three-stage structure in which G, R and G are stacked, or a three-stage structure in which R, G and R are stacked. In addition, other layers may be provided between two light-emitting layers.

[0512] In addition, by adopting a microcavity structure, a light-emitting element having a structure that emits white light may emit light while strengthening a specific color such as red, green, or blue.

[0513] Or, for example Fig.21BThe light-emitting elements 130R, 130G, and 130B shown emit blue light. In this case, the EL layer 113 includes one or more light-emitting layers that emit blue light. With respect to the sub-pixel 11B that emits blue light, the blue light emitted by the light-emitting element 130B can be extracted. In addition, with respect to the sub-pixel 11R that emits red light and the sub-pixel 11G that emits green light, by providing a color conversion layer between the light-emitting element 130R or the light-emitting element 130G and the substrate 152, the blue light emitted by the light-emitting element 130R or the light-emitting element 130G can be converted into light with a longer wavelength and extracted as red light or green light. Furthermore, it is preferable to provide a coloring layer 132R between the color conversion layer on the light-emitting element 130R and the substrate 152, and to provide a coloring layer 132G between the color conversion layer on the light-emitting element 130G and the substrate 152. A portion of the light emitted by the light-emitting element is sometimes transmitted without being converted by the color conversion layer. By extracting the light that has passed through the color conversion layer through the coloring layer, the coloring layer can absorb light other than the desired color light, thereby improving the color purity of the light presented by the sub-pixel.

[0514] [Display device 50C] Fig. 22 The main difference between the illustrated display device 50C and the display device 50B is that the former is a bottom emission type display device.

[0515] Light emitted by the light emitting element is emitted toward the substrate 151. A material having high visible light transmittance is preferably used for the substrate 151. On the other hand, there is no limitation on the light transmittance of the material used for the substrate 152.

[0516] A light shielding layer 117 is preferably formed between the substrate 151 and the transistor. Fig. 22 The following example is shown: a light shielding layer 117 is provided on a substrate 151, an insulating layer 153 is provided on the light shielding layer 117, and a transistor 205D, a transistor 205R (not shown), a transistor 205G, and a transistor 205B are provided on the insulating layer 153. In addition, a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B are provided on an insulating layer 218, and an insulating layer 235 is provided on the coloring layers 132R, the coloring layer 132G, and the coloring layer 132B.

[0517] The light emitting element 130R overlapping the colored layer 132R includes a pixel electrode 111R, an EL layer 113 , and a common electrode 115 .

[0518] The light emitting element 130G overlapping the colored layer 132G includes a pixel electrode 111G, an EL layer 113 , and a common electrode 115 .

[0519] The light emitting element 130B overlapping the colored layer 132B includes a pixel electrode 111B, an EL layer 113 , and a common electrode 115 .

[0520] The pixel electrodes 111R, 111G, and 111B are each made of a material having high visible light transmittance. The common electrode 115 is preferably made of a material that reflects visible light. Since a metal with low resistance or the like can be used for the common electrode 115 in a bottom emission display device, a voltage drop caused by the resistance of the common electrode 115 can be suppressed, and high display quality can be achieved.

[0521] A transistor according to one embodiment of the present invention can be miniaturized and have a reduced occupied area, so that the aperture ratio of a pixel can be increased or the size of a pixel can be reduced in a bottom emission structure display device.

[0522] [Display device 50D] Fig.23A The main difference between the display device 50D shown and the display device 50A is that the former includes a light receiving element 130S.

[0523] The display device 50D includes a light-emitting element and a light-receiving element in a pixel. In the display device 50D, it is preferable to use an organic EL element as the light-emitting element and an organic photodiode as the light-receiving element. The organic EL element and the organic photodiode can be formed on the same substrate. Therefore, the organic photodiode can be installed in the display device using the organic EL element.

[0524] In the display device 50D in which pixels include a light-emitting element and a light-receiving element, the pixels have a light-receiving function, so the display device can detect the contact or approach of an object while displaying an image. Therefore, the display unit 162 has one or both of a camera function and a sensing function in addition to an image display function. For example, instead of displaying an image in all sub-pixels included in the display device 50D, a part of the sub-pixels can be used as a light source to emit light, another part of the sub-pixels can be used for light detection, and the remaining sub-pixels can be used to display an image.

[0525] Therefore, it is not necessary to separately provide a light receiving unit and a light source with the display device 50D, and the number of components of the electronic device can be reduced. For example, it is not necessary to separately provide a biometric device installed in the electronic device or an electrostatic capacitive touch panel for scrolling, etc. Therefore, by using the display device 50D, an electronic device with reduced manufacturing cost can be provided.

[0526] When the light receiving element is used for the image sensor, the display device 50D can capture images using the light receiving element. For example, the image sensor can be used to capture images for personal identification using fingerprints, palm prints, irises, vein shapes (including vein shapes, artery shapes) or faces.

[0527] In addition, the light receiving element can be used for a touch sensor (also called a direct touch sensor) or a non-contact sensor (also called a floating sensor, a floating touch sensor, a non-touch sensor), etc. A touch sensor can detect an object when the object (a finger, a hand, a pen, etc.) directly contacts the display device. In addition, a non-contact sensor can detect the object even if the object does not contact the display device.

[0528] The light emitting element 130S includes a pixel electrode 111S on the insulating layer 235, a functional layer 113S on the pixel electrode 111S, and a common electrode 115 on the functional layer 113S. Light Lin is incident on the functional layer 113S from the outside of the display device 50D.

[0529] The pixel electrode 111S is electrically connected to the conductive layer 112 b included in the transistor 205S through an opening provided in the insulating layer 106 , the insulating layer 218 , and the insulating layer 235 .

[0530] The end portion of the pixel electrode 111S is covered with the insulating layer 237 .

[0531] The common electrode 115 is a continuous film shared by the light receiving element 130S, the light emitting element 130R (not shown), the light emitting element 130G, and the light emitting element 130B. The common electrode 115 shared by the light emitting element and the light receiving element is electrically connected to the conductive layer 123 provided in the connection portion 140 .

[0532] The functional layer 113S includes at least an active layer (also referred to as a photoelectric conversion layer). The active layer includes a semiconductor. As the semiconductor, inorganic semiconductors such as silicon and organic semiconductors including organic compounds can be cited. In this embodiment, an example of using an organic semiconductor as a semiconductor contained in the active layer is shown. By using an organic semiconductor, the light-emitting layer and the active layer can be formed by the same method (e.g., vacuum evaporation method), and the manufacturing equipment can be used together, so it is preferred.

[0533] The functional layer 113S may also include a layer containing a substance with high hole transport properties, a substance with high electron transport properties, or a bipolar substance as a layer other than the active layer. In addition, without limitation thereto, a layer containing a substance with high hole injection properties, a hole blocking material, a substance with high electron injection properties, or an electron blocking material may also be included. As the functional layer 113S, for example, the above-mentioned materials that can be used for light-emitting elements can be used.

[0534] The light receiving element may use a low molecular weight compound or a high molecular weight compound, and may also contain an inorganic compound. The layer constituting the light receiving element may be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet, or coating.

[0535] Fig. 23B and Fig.23CThe display device 50D shown includes a layer 353 having a light receiving element, a circuit layer 355 , and a layer 357 having a light emitting element between a substrate 151 and a substrate 152 .

[0536] The layer 353 includes, for example, the light receiving element 130S. The layer 357 includes, for example, the light emitting elements 130R, 130G, and 130B.

[0537] The circuit layer 355 includes a circuit for driving the light-receiving element and a circuit for driving the light-emitting element. The circuit layer 355 includes, for example, transistors 205R, 205G, and 205B. In addition, one or more switches, transistors, capacitors, resistors, wirings, terminals, etc. may be provided in the circuit layer 355.

[0538] Fig. 23B This is an example of using the light receiving element 130S as a touch sensor. Fig. 23B As shown, when the finger 352 touching the display device 50D reflects the light emitted by the light emitting element in the layer 357, the light receiving element in the layer 353 detects the reflected light. Thus, it is possible to detect that the finger 352 has touched the display device 50D.

[0539] Fig.23C This is an example of using the light receiving element 130S as a non-contact sensor. Fig.23C As shown, when a finger 352 approaching (ie, not touching) the display device 50D reflects light emitted by the light emitting element in the layer 357 , the light receiving element in the layer 353 detects the reflected light.

[0540] [Display device 50E] Fig.24A The display device 50E shown is an example of a display device using an MML (Metal Mask Less) structure. That is, the display device 50E includes a light-emitting element that is not manufactured using a high-definition metal mask. Note that the stacked structure from the substrate 151 to the insulating layer 235 and the stacked structure from the protective layer 131 to the substrate 152 are the same as those of the display device 50A, so the description thereof is omitted.

[0541] exist Fig.24A In the embodiment, light emitting elements 130R, 130G, and 130B are disposed on the insulating layer 235 .

[0542] The light emitting element 130R includes a conductive layer 124R on the insulating layer 235 , a conductive layer 126R on the conductive layer 124R, a layer 133R on the conductive layer 126R, a common layer 114 on the layer 133R, and a common electrode 115 on the common layer 114 . Fig.24AThe light emitting element 130R shown emits red light (R). The layer 133R includes a light emitting layer that emits red light. In the light emitting element 130R, the layer 133R and the common layer 114 may be collectively referred to as an EL layer. One or both of the conductive layer 124R and the conductive layer 126R may be referred to as a pixel electrode.

[0543] The light emitting element 130G includes a conductive layer 124G on the insulating layer 235 , a conductive layer 126G on the conductive layer 124G, a layer 133G on the conductive layer 126G, a common layer 114 on the layer 133G, and a common electrode 115 on the common layer 114 . Fig.24A The light emitting element 130G shown emits green light (G). The layer 133G includes a light emitting layer that emits green light. In the light emitting element 130G, the layer 133G and the common layer 114 can be collectively referred to as an EL layer. One or both of the conductive layer 124G and the conductive layer 126G can be referred to as a pixel electrode.

[0544] The light emitting element 130B includes a conductive layer 124B on the insulating layer 235 , a conductive layer 126B on the conductive layer 124B, a layer 133B on the conductive layer 126B, a common layer 114 on the layer 133B, and a common electrode 115 on the common layer 114 . Fig.24A The light emitting element 130B shown emits blue light (B). Layer 133B includes a light emitting layer that emits blue light. In the light emitting element 130B, layer 133B and common layer 114 may be collectively referred to as an EL layer. One or both of conductive layer 124B and conductive layer 126B may be referred to as a pixel electrode.

[0545] In this specification and the like, an island-shaped layer provided for each light-emitting element in the EL layer included in the light-emitting element is referred to as a layer 133R, a layer 133G, or a layer 133B, and a layer shared by a plurality of light-emitting elements is referred to as a common layer 114. In addition, in this specification and the like, the layer 133R, the layer 133G, and the layer 133B not including the common layer 114 may be referred to as an island-shaped EL layer, an EL layer formed in an island shape, or the like.

[0546] Layer 133R, layer 133G, and layer 133B are separated from each other. By providing an island-shaped EL layer in each light-emitting element, leakage current between adjacent light-emitting elements can be suppressed. Therefore, unintentional light emission caused by crosstalk can be suppressed, thereby realizing a display device with a very high contrast.

[0547] In addition, Fig.24A In FIG. 1 , the film thicknesses of the layers 133R, 133G, and 133B are shown as being the same, but the present invention is not limited thereto. The thicknesses of the layers 133R, 133G, and 133B may be different from each other.

[0548] Conductive layer 124R is electrically connected to conductive layer 112b included in transistor 205R through openings provided in insulating layer 106, insulating layer 218, and insulating layer 235. Similarly, conductive layer 124G is electrically connected to conductive layer 112b included in transistor 205G, and conductive layer 124B is electrically connected to conductive layer 112b included in transistor 205B.

[0549] Conductive layers 124R, 124G, and 124B are formed to cover the openings provided in insulating layer 235. Concave portions of conductive layers 124R, 124G, and 124B are filled with layer 128, respectively.

[0550] Layer 128 has the function of flattening the concave portions of conductive layers 124R, 124G, and 124B. Conductive layers 126R, 126G, and 126B electrically connected to conductive layers 124R, 124G, and 124B are provided on conductive layers 124R, 124G, and 124B and layer 128. Therefore, the region overlapping the concave portions of conductive layers 124R, 124G, and 124B can also be used as a light-emitting region, thereby increasing the aperture ratio of the pixel. Conductive layers 124R and 126R are preferably conductive layers used as reflective electrodes.

[0551] Layer 128 may be an insulating layer or a conductive layer. Layer 128 may be formed of various inorganic insulating materials, organic insulating materials, and conductive materials as appropriate. In particular, layer 128 is preferably formed of an insulating material, and is particularly preferably formed of an organic insulating material. As layer 128, for example, an organic insulating material that can be used for the above-mentioned insulating layer 237 can be used.

[0552] Although Fig.24A An example is shown in which the top surface of the layer 128 has a flat portion, but there is no particular limitation on the shape of the layer 128. The top surface of the layer 128 may have at least one of a convex curved surface, a concave curved surface, and a flat surface.

[0553] In addition, the height of the top surface of layer 128 may be the same or substantially the same as the height of the top surface of conductive layer 124R, or may be different from each other. For example, the height of the top surface of layer 128 may be lower or higher than the height of the top surface of conductive layer 124R.

[0554] The end of the conductive layer 126R may also be aligned with the end of the conductive layer 124R, and may also cover the side of the end of the conductive layer 124R. Each end of the conductive layer 124R and the conductive layer 126R preferably has a tapered shape. Specifically, each end of the conductive layer 124R and the conductive layer 126R preferably has a tapered shape with a tapered angle greater than 0 degrees and less than 90 degrees. When the end of the pixel electrode has a tapered shape, the layer 133R provided along the side of the pixel electrode has an inclined portion. By making the side of the pixel electrode have a tapered shape, the coverage of the EL layer provided along the side of the pixel electrode can be improved.

[0555] Since the conductive layers 124G and 126G and the conductive layers 124B and 126B are the same as the conductive layers 124R and 126R, detailed descriptions thereof will be omitted.

[0556] The top surface and side surfaces of the conductive layer 126R are covered by the layer 133R. Similarly, the top surface and side surfaces of the conductive layer 126G are covered by the layer 133G, and the top surface and side surfaces of the conductive layer 126B are covered by the layer 133B. Therefore, the entire region where the conductive layers 126R, 126G, and 126B are provided can be used as the light-emitting region of the light-emitting elements 130R, 130G, and 130B, thereby increasing the aperture ratio of the pixel.

[0557] Part of the top surface and side surfaces of the layers 133R, 133G, and 133B are covered by insulating layers 125 and 127. A common layer 114 is provided on the layers 133R, 133G, 133B, and the insulating layers 125 and 127, and a common electrode 115 is provided on the common layer 114. Both the common layer 114 and the common electrode 115 are continuous films shared by a plurality of light-emitting elements.

[0558] exist Fig.24A In the embodiment, there is no arrangement between the conductive layer 126R and the layer 133R. Fig.21A In other words, the display device 50E is not provided with an insulating layer (also referred to as a partition wall, a dam, a spacer, etc.) that contacts the pixel electrode and covers the top surface end of the pixel electrode. Therefore, the interval between adjacent light-emitting elements can be made very small. Thus, a high-definition or high-resolution display device can be realized. In addition, there is no need for a mask for forming the insulating layer, thereby reducing the manufacturing cost of the display device.

[0559] As described above, layer 133R, layer 133G, and layer 133B all include a light-emitting layer. Layer 133R, layer 133G, and layer 133B preferably include a light-emitting layer and a carrier transport layer (electron transport layer or hole transport layer) on the light-emitting layer. In addition, layer 133R, layer 133G, and layer 133B preferably include a light-emitting layer and a carrier blocking layer (hole blocking layer or electron blocking layer) on the light-emitting layer. In addition, layer 133R, layer 133G, and layer 133B may also include a light-emitting layer, a carrier blocking layer on the light-emitting layer, and a carrier transport layer on the carrier blocking layer. The surfaces of layer 133R, layer 133G, and layer 133B are exposed in the manufacturing process of the display device, so by providing one or both of the carrier transport layer and the carrier blocking layer on the light-emitting layer, the light-emitting layer can be prevented from being exposed to the outermost surface and the damage to the light-emitting layer can be reduced. As a result, the reliability of the light-emitting element can be improved.

[0560] The common layer 114 includes, for example, an electron injection layer or a hole injection layer. Alternatively, the common layer 114 may include a stack of an electron transport layer and an electron injection layer, or a stack of a hole transport layer and a hole injection layer. The light-emitting elements 130R, 130G, and 130B share the common layer 114.

[0561] The side surfaces of the layers 133R, 133G, and 133B are covered with the insulating layer 125. The insulating layer 127 covers the side surfaces of the layers 133R, 133G, and 133B via the insulating layer 125.

[0562] By covering the side surfaces of the layers 133R, 133G, and 133B (or even covering a portion of the top surfaces thereof) with at least one of the insulating layer 125 and the insulating layer 127, the common layer 114 (or the common electrode 115) can be prevented from contacting the pixel electrode and the side surfaces of the layers 133R, 133G, and 133B, thereby preventing the light-emitting element from being short-circuited. Thus, the reliability of the light-emitting element can be improved.

[0563] The insulating layer 125 is preferably in contact with the side surfaces of the layers 133R, 133G, and 133B. By adopting a structure in which the insulating layer 125 is in contact with the layers 133R, 133G, and 133B, film peeling of the layers 133R, 133G, and 133B can be prevented, thereby improving the reliability of the light-emitting element.

[0564] The insulating layer 127 is provided on the insulating layer 125 so as to fill the recessed portion of the insulating layer 125. The insulating layer 127 preferably covers at least a part of the side surface of the insulating layer 125.

[0565] By providing the insulating layer 125 and the insulating layer 127, the space between adjacent island-shaped layers can be filled, so that the unevenness of the formed surface of the layer (for example, the carrier injection layer, the common electrode, etc.) provided on the island-shaped layer can be reduced and further flattened. Therefore, the coverage of the carrier injection layer or the common electrode, etc. can be improved.

[0566] The common layer 114 and the common electrode 115 are arranged on the layer 133R, the layer 133G, the layer 133B, the insulating layer 125, and the insulating layer 127. Before the insulating layer 125 and the insulating layer 127 are arranged, steps are generated due to the area where the pixel electrode and the island EL layer are arranged and the area where the pixel electrode and the island EL layer are not arranged (the area between the light-emitting elements). The display device of one embodiment of the present invention can flatten the step by including the insulating layer 125 and the insulating layer 127, thereby improving the coverage of the common layer 114 and the common electrode 115. Therefore, poor connection caused by disconnection can be suppressed. Alternatively, the resistance increase caused by the local thin filmization of the common electrode 115 due to the step can be suppressed.

[0567] The top surface of the insulating layer 127 preferably has a flatter shape. The top surface of the insulating layer 127 may also have at least one of a flat surface, a convex surface, and a concave surface. For example, the top surface of the insulating layer 127 preferably has a convex surface with a large curvature radius.

[0568] The insulating layer 125 may be an insulating layer containing an inorganic material. As the insulating layer 125, for example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film may be used. Specific examples of these inorganic insulating films are as described above. The insulating layer 125 may be a single-layer structure or a stacked-layer structure. In particular, the selectivity of aluminum oxide to the EL layer is high in etching, and it has a function of protecting the EL layer in the formation of the insulating layer 127 described later, so it is preferred. In particular, by using an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by the ALD method for the insulating layer 125, an insulating layer 125 with fewer pinholes and a good function of protecting the EL layer can be formed. In addition, the insulating layer 125 may also have a stacked-layer structure of a film formed by the ALD method and a film formed by the sputtering method. For example, the insulating layer 125 may have a stacked-layer structure of an aluminum oxide film formed by the ALD method and a silicon nitride film formed by the sputtering method.

[0569] The insulating layer 125 preferably has a function of a blocking insulating layer with respect to at least one of water and oxygen. The insulating layer 125 preferably has a function of suppressing the diffusion of at least one of water and oxygen. In addition, the insulating layer 125 preferably has a function of capturing or fixing (also referred to as doping) at least one of water and oxygen.

[0570] When the insulating layer 125 is used as a blocking insulating layer, it can have a structure that suppresses the entry of impurities (typically, at least one of water and oxygen) that may diffuse from the outside into each light-emitting element. By adopting this structure, a light-emitting element with high reliability can be provided, and a display device with high reliability can be provided.

[0571] In addition, the concentration of the impurity element in the insulating layer 125 is preferably low. Thus, it is possible to suppress the impurities from being mixed into the EL layer from the insulating layer 125 and deteriorating the EL layer. In addition, by reducing the concentration of the impurity element in the insulating layer 125, the barrier property against at least one of water and oxygen can be improved. For example, it is preferable that one of the hydrogen concentration and the carbon concentration in the insulating layer 125 is sufficiently low, and it is preferable that both the hydrogen concentration and the carbon concentration are sufficiently low.

[0572] The insulating layer 127 provided on the insulating layer 125 has the function of flattening the large unevenness of the insulating layer 125 formed between adjacent light emitting elements. In other words, the insulating layer 127 improves the flatness of the surface on which the common electrode 115 is formed.

[0573] As the insulating layer 127, an insulating layer containing an organic material can be used as appropriate. As the organic material, a photosensitive resin is preferably used, for example, a photosensitive resin composition containing an acrylic resin is preferably used. Note that in this specification, etc., acrylic resin does not refer to only polymethacrylate or methacrylic resin, and sometimes refers to acrylic polymers in a broad sense as a whole.

[0574] In addition, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimide amide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin and precursors of the above resins can also be used as the insulating layer 127. In addition, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose or alcohol-soluble polyamide resin can also be used as the insulating layer 127. In addition, photoresist can also be used as a photosensitive resin. As a photosensitive resin, a positive material or a negative material can be used.

[0575] A material that absorbs visible light may also be used as the insulating layer 127. By absorbing the light emitted from the light-emitting element by the insulating layer 127, it is possible to suppress the leakage of light from the light-emitting element through the insulating layer 127 to the adjacent light-emitting element (stray light). Therefore, the display quality of the display device can be improved. In addition, the display quality can be improved even if a polarizing plate is not used in the display device, so the display device can be made lighter and thinner.

[0576] As materials that absorb visible light, materials including pigments such as black, materials including dyes, resin materials including light absorption (for example, polyimide, etc.), and resin materials that can be used for color filters (color filter materials) can be cited. In particular, when using a resin material formed by stacking or mixing two or more colors of color filter materials, the effect of shielding visible light can be improved, so it is preferred. In particular, by mixing three or more colors of color filter materials, a black or nearly black resin layer can be achieved.

[0577] [Display device 50F] Fig. 24B An example of a cross section of the display unit 162 of the display device 50F is shown. The main difference between the display device 50F and the display device 50E is that the display device 50F includes a light emitting element having a layer 133 and a coloring layer (color filter, etc.) in each sub-pixel of each color. Fig. 24B The structure shown can be combined with Fig.24A The structure shown includes the region of the FPC 172, the circuit portion 164, the stacked structure from the substrate 151 to the insulating layer 235 of the display portion 162, the connection portion 140, and the end portion.

[0578] Fig. 24B The display device 50F shown includes light emitting elements 130R, 130G, and 130B, a coloring layer 132R that transmits red light, a coloring layer 132G that transmits green light, a coloring layer 132B that transmits blue light, and the like.

[0579] The light emitted by the light emitting element 130R is extracted as red light to the outside of the display device 50F through the coloring layer 132R. Similarly, the light emitted by the light emitting element 130G is extracted as green light to the outside of the display device 50F through the coloring layer 132G. The light emitted by the light emitting element 130B is extracted as blue light to the outside of the display device 50F through the coloring layer 132B.

[0580] The light-emitting elements 130R, 130G, and 130B each include a layer 133. These three layers 133 are formed using the same process and the same material. In addition, these three layers 133 are separated from each other. By providing an island-shaped EL layer in each light-emitting element, leakage current between adjacent light-emitting elements can be suppressed. Therefore, unintentional light emission caused by crosstalk can be suppressed, thereby realizing a display device with very high contrast.

[0581] For example, Fig. 24B The light emitting elements 130R, 130G, and 130B shown emit white light. The white light emitted by the light emitting elements 130R, 130G, and 130B passes through the colored layers 132R, 132G, and 132B, thereby obtaining light of a desired color.

[0582] Or, for example Fig. 24B The light-emitting elements 130R, 130G, and 130B shown emit blue light. In this case, the layer 133 includes one or more light-emitting layers that emit blue light. With respect to the sub-pixel 11B that presents blue light, the blue light emitted by the light-emitting element 130B can be extracted. In addition, with respect to the sub-pixel 11R that presents red light and the sub-pixel 11G that presents green light, by providing a color conversion layer between the light-emitting element 130R or the light-emitting element 130G and the substrate 152, the blue light emitted by the light-emitting element 130R or the light-emitting element 130G can be converted into light with a longer wavelength and extracted as red light or green light. Furthermore, it is preferred that a coloring layer 132R is provided between the color conversion layer on the light-emitting element 130R and the substrate 152, and a coloring layer 132G is provided between the color conversion layer on the light-emitting element 130G and the substrate 152. By extracting the light that transmits the color conversion layer through the coloring layer, the color purity of the light presented by the sub-pixel can be improved by absorbing light other than the desired color light by the coloring layer.

[0583] [Display device 50G] Fig.25 The main difference between the illustrated display device 50G and the display device 50F is that the former is a bottom emission type display device.

[0584] Light emitted by the light emitting element is emitted toward the substrate 151. A material having high visible light transmittance is preferably used for the substrate 151. On the other hand, there is no limitation on the light transmittance of the material used for the substrate 152.

[0585] A light shielding layer 117 is preferably formed between the substrate 151 and the transistor. Fig.25 The following example is shown: a light shielding layer 117 is provided on a substrate 151, an insulating layer 153 is provided on the light shielding layer 117, and a transistor 205D, a transistor 205R (not shown), a transistor 205G, and a transistor 205B are provided on the insulating layer 153. In addition, a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B are provided on an insulating layer 218, and an insulating layer 235 is provided on the coloring layers 132R, the coloring layer 132G, and the coloring layer 132B.

[0586] The light emitting element 130R overlapping the colored layer 132R includes a conductive layer 124R, a conductive layer 126R, a layer 133 , a common layer 114 , and a common electrode 115 .

[0587] The light emitting element 130G overlapping the colored layer 132G includes the conductive layer 124G, the conductive layer 126G, the layer 133 , the common layer 114 , and the common electrode 115 .

[0588] The light emitting element 130B overlapping the colored layer 132B includes a conductive layer 124B, a conductive layer 126B, a layer 133 , a common layer 114 , and a common electrode 115 .

[0589] Conductive layers 124R, 124G, 124B, 126R, 126G, and 126B are each made of a material having high visible light transmittance. The common electrode 115 is preferably made of a material that reflects visible light. Since a metal with low resistivity can be used for the common electrode 115 in a bottom emission type display device, a voltage drop caused by the resistance of the common electrode 115 can be suppressed, and high display quality can be achieved.

[0590] A transistor according to one embodiment of the present invention can be miniaturized and have a reduced occupied area, so that the aperture ratio of a pixel can be increased or the size of a pixel can be reduced in a bottom emission structure display device.

[0591] [Display device 50H] Fig.26 The display device 50H shown is a VA-mode liquid crystal display device.

[0592] The substrate 151 and the substrate 152 are attached to each other using the adhesive layer 144. In addition, a liquid crystal 262 is sealed in a region surrounded by the substrate 151, the substrate 152, and the adhesive layer 144. The polarizing plate 260a is located on the outer surface of the substrate 152, and the polarizing plate 260b is located on the outer surface of the substrate 151. In addition, although not shown in the figure, a backlight may be provided on the outer side of the polarizing plate 260a or the outer side of the polarizing plate 260b.

[0593] The substrate 151 is provided with transistors 205D, 205R, and 205G, a connection portion 204, a spacer 224, and the like. The transistor 205D is provided in the circuit portion 164, and the transistors 205R and 205G are provided in the display portion 162. The conductive layer 112b included in the transistors 205R and 205G is used as a pixel electrode of the liquid crystal element 60.

[0594] The substrate 152 is provided with the coloring layers 132R and 132G, the light shielding layer 117 , the insulating layer 225 , the conductive layer 263 , and the like. The conductive layer 263 is used as a common electrode of the liquid crystal element 60 .

[0595] The transistors 205D, 205R, and 205G include a conductive layer 112a, a semiconductor layer 108, an insulating layer 106, a conductive layer 104, and a conductive layer 112b, respectively. The conductive layer 112a is used as one of a source electrode and a drain electrode, and the conductive layer 112b is used as the other of the source electrode and the drain electrode. The conductive layer 104 is used as a gate electrode. A portion of the insulating layer 106 is used as a gate insulating layer.

[0596] Furthermore, a conductive layer 103 is provided over the conductive layer 112a and in contact therewith. The conductive layer 103 includes a conductive material having higher conductivity than the conductive layer 112a and serves as an auxiliary wiring. Furthermore, the conductive layer 103 is in contact with part of the semiconductor layer 108.

[0597] As described above, in this embodiment, an example of using OS transistors as transistors 205D, 205R, and 205G is shown. As transistors 205D, 205R, and 205G, transistors of one embodiment of the present invention can be used. That is, in the display device 50H, both the display unit 162 and the circuit unit 164 include transistors of one embodiment of the present invention. By using a transistor of one embodiment of the present invention in the display unit 162, the pixel size can be reduced and high definition can be achieved. In addition, by using a transistor of one embodiment of the present invention in the circuit unit 164, the area occupied by the circuit unit 164 can be reduced and a narrow frame can be achieved. For the transistor of one embodiment of the present invention, reference can be made to the description of the above embodiment.

[0598] Furthermore, the transistors 205D, 205R, and 205G are covered with an insulating layer 218. The insulating layer 218 serves as a protective layer for the transistors 205D, 205R, and 205G.

[0599] The sub-pixels included in the display unit 162 include transistors, a liquid crystal element 60, and a coloring layer. For example, a sub-pixel that presents red light includes a transistor 205R, a liquid crystal element 60, and a coloring layer 132R that transmits red light. In addition, a sub-pixel that presents green light includes a transistor 205G, a liquid crystal element 60, and a coloring layer 132G that transmits green light. Although not shown, a sub-pixel that presents blue light also includes a transistor, a liquid crystal element 60, and a coloring layer that transmits blue light.

[0600] The liquid crystal element 60 includes a conductive layer 112 b , a conductive layer 263 , and a liquid crystal 262 sandwiched therebetween.

[0601] In addition, a conductive layer 264 is provided on the substrate 151 and is located on the same surface as the conductive layer 112a. The conductive layer 264 has a portion overlapping the conductive layer 112b via the insulating layer 110 (insulating layer 110a, insulating layer 110b, and insulating layer 110c). A storage capacitor is formed by the conductive layer 112b, the conductive layer 264, and the insulating layer 110 therebetween. Note that more than one insulating layer may be provided between the conductive layer 112b and the conductive layer 264, and one or two of the insulating layers 110 may be removed by etching.

[0602] The insulating layer 225 is provided on the substrate 152 side so as to cover the coloring layers 132R and 132G and the light shielding layer 117. The insulating layer 225 can also be used as a planarization film. The insulating layer 225 can make the surface of the conductive layer 263 substantially planar, thereby making the alignment state of the liquid crystal 262 uniform.

[0603] In addition, in the conductive layer 263 and the insulating layer 218, an alignment film for controlling the alignment of the liquid crystal 262 may be provided on the surface in contact with the liquid crystal 262. (See Fig.28A and Fig.28B Orientation film 265 in).

[0604] The conductive layer 112b and the conductive layer 263 transmit visible light. That is, the display device 50H can be made into a transmissive liquid crystal display device. For example, when the backlight source is arranged on one side of the substrate 152, the light of the backlight source polarized by the polarizer 260a passes through the substrate 152, the conductive layer 263, the liquid crystal 262, the conductive layer 112b and the substrate 151 to reach the polarizer 260b. At this time, the orientation of the liquid crystal 262 can be controlled by the voltage applied between the conductive layer 112b and the conductive layer 263, thereby controlling the optical modulation of the light. That is, the intensity of the light emitted through the polarizer 260b can be controlled. In addition, because the light outside the specified wavelength region of the incident light is absorbed by the coloring layer, the extracted light becomes, for example, red light.

[0605] Here, as the polarizer 260b, a linear polarizer or a circular polarizer can be used. For example, a polarizer formed by laminating a linear polarizer and a quarter-wave phase difference plate can be used. By using a circular polarizer as the polarizer 260b, external light reflection can be suppressed.

[0606] In addition, when a circular polarizer is used as the polarizer 260b, a circular polarizer or a general linear polarizer may be used as the polarizer 260a. The desired contrast may be achieved by adjusting the cell gap, orientation, and drive voltage of the liquid crystal element used in the liquid crystal element 60 according to the types of polarizers used for the polarizers 260a and 260b.

[0607] Conductive layer 263 is electrically connected to conductive layer 166b provided on the substrate 151 side through connector 223 in connection portion 140. Conductive layer 166b is electrically connected to conductive layer 165b through an opening provided in insulating layer 110. Thus, a potential or a signal can be supplied to conductive layer 263 from an FPC or an IC provided on the substrate 151 side. Fig.26 An example is shown in which the conductive layer 165b is formed using the same material and process as the conductive layer 112a and the conductive layer 103, and an example is shown in which the conductive layer 166b is formed using the same material and process as the conductive layer 112b.

[0608] For example, conductive particles can be used for the connector 223. As conductive particles, particles such as resin or silicon dioxide with a metal material coated on the surface can be used. As metal materials, nickel or gold is preferably used because it can reduce contact resistance. In addition, particles with two or more metal materials coated in layers, such as nickel coated with gold, are preferably used. In addition, the connector 223 is preferably made of a material that can be elastically deformed or plastically deformed. In this case, the conductive particles sometimes become Fig.26 The connector 223 is preferably configured to be covered by the adhesive layer 144. For example, the connector 223 is preferably dispersed in the adhesive layer 144 before curing.

[0609] A connection portion 204 is provided in a region near an end of the substrate 151. In the connection portion 204, the conductive layer 166a is electrically connected to the FPC 172 via the connection layer 242. The conductive layer 166a is connected to the conductive layer 165a via an opening provided in the insulating layer 110. Fig.26 An example is shown in which the conductive layer 165a is formed using the same material and process as the conductive layer 112a and the conductive layer 103, and an example is shown in which the conductive layer 166a is formed using the same material and process as the conductive layer 112b.

[0610] [Display device 50I] Fig. 27 The display device 50I shown is a liquid crystal display device of FFS mode. The display device 50I is different from the display device 50H mainly in the structure of the liquid crystal element 60.

[0611] A conductive layer 263 serving as a common electrode of the liquid crystal element 60 is provided on the insulating layer 110, and an insulating layer 261 is provided on the conductive layer 263. Furthermore, a conductive layer 112b having the other of the source electrode and the drain electrode of the transistor and the function of the pixel electrode of the liquid crystal element 60 is provided on the insulating layer 261. An insulating layer 218 is provided on the conductive layer 112b.

[0612] The conductive layer 112b has a comb-teeth shape or a shape provided with slits when viewed from a plan view. The conductive layer 263 is arranged to overlap with the conductive layer 112b. In the region overlapping with the colored layer, there is a portion on the conductive layer 263 where the conductive layer 112b is not arranged.

[0613] A capacitor is formed by stacking the conductive layer 112b and the conductive layer 263 with the insulating layer 261 interposed therebetween. Therefore, it is not necessary to form a capacitor separately, and the aperture ratio of the pixel can be increased.

[0614] In the liquid crystal element 60, both the conductive layer 112b and the conductive layer 263 may have a comb-tooth-shaped top surface shape. On the other hand, as shown in the display device 50I, only one of the conductive layer 112b and the conductive layer 263 in the liquid crystal element 60 has a comb-tooth-shaped top surface shape, so that the conductive layer 112b and the conductive layer 263 partially overlap. As a result, the capacitance between the conductive layer 112b and the conductive layer 263 can be used as a storage capacitance, and there is no need to provide a capacitor separately, so the aperture ratio of the display device can be improved.

[0615] [Display device 50J] exist Fig.28A In the display device 50J shown, the portion of the insulating layer 110b overlapping with the liquid crystal element 60 is removed by etching. The liquid crystal element 60 included in the display device 50J includes a portion in which the conductive layer 112c, the insulating layer 110a, the insulating layer 110c, and the conductive layer 112b are stacked in sequence. Since the liquid crystal element 60 and the insulating layer 110b do not overlap, not only can the light transmittance be improved, but also the number of interfaces located on the path of the light from the light source can be reduced, thereby suppressing the influence of interface reflection and interface scattering.

[0616] The conductive layer 112b is used as a pixel electrode of the liquid crystal element 60. The conductive layer 112c is used as a common electrode of the liquid crystal element 60. The conductive layer 112c is formed using the same conductive film as the conductive layer 112a.

[0617] Note that the portion of either or both of the insulating layer 106 and the insulating layer 218 that overlaps with the liquid crystal element 60 can be removed by etching. Alternatively, the insulating layer 218 may not be provided. As a result, the electric field of the conductive layer 112b and the conductive layer 112c is easily transmitted to the liquid crystal 262, and the liquid crystal element 60 can operate at high speed. Furthermore, not only can the light transmittance of the portion overlapping with the liquid crystal element 60 be improved, but also the influence of interface reflection and interface scattering can be suppressed. In addition, the portion of either or both of the insulating layer 110a and the insulating layer 110c that overlaps with the liquid crystal element 60 can be removed by etching. As a result, the electric field of the conductive layer 112b and the conductive layer 112c is easily transmitted to the liquid crystal 262. Sometimes, the capacitance between the conductive layer 112b and the conductive layer 112c can also be increased.

[0618] In the liquid crystal element 60, both the conductive layer 112b and the conductive layer 112c may have a comb-tooth-shaped top surface shape. On the other hand, as shown in the display device 50J, only one of the conductive layer 112b and the conductive layer 112c in the liquid crystal element 60 has a comb-tooth-shaped top surface shape, so that the conductive layer 112b and the conductive layer 112c partially overlap. As a result, the capacitance between the conductive layer 112b and the conductive layer 112c can be used as a storage capacitor, and there is no need to provide a capacitor separately, so the aperture ratio of the display device can be improved.

[0619] [Display device 50K] Fig.28B The main difference between the display device 50K shown and the display device 50I is that the common electrode is provided on the pixel electrode. The conductive layer 112b included in the transistor 100 is used as the pixel electrode of the liquid crystal element 60. The insulating layer 106 and the insulating layer 218 are provided on the conductive layer 112b, and the conductive layer 263 is provided on the insulating layer 218. The conductive layer 263 is used as the common electrode of the liquid crystal element 60. The conductive layer 263 has a comb shape or a shape provided with slits when viewed from a plane.

[0620] [Example of a method for manufacturing a display device] The following describes a method for manufacturing a display device using an MML (Metal Mask Less) structure with reference to FIG29. Here, the process of manufacturing a light-emitting element without a high-definition metal mask is described in detail. FIG29 is a cross-sectional view of three light-emitting elements and a connection portion 140 included in a display portion 162 in each process.

[0621] When manufacturing a light-emitting element, a vacuum process such as evaporation and a solution process such as spin coating and inkjet can be used. As an evaporation method, physical evaporation methods (PVD methods) such as sputtering, ion plating, ion beam evaporation, molecular beam evaporation, vacuum evaporation, and chemical vapor deposition (CVD methods) can be cited. In particular, a functional layer (hole injection layer, hole transport layer, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer, electron injection layer, charge generation layer, etc.) included in the EL layer can be formed using evaporation (vacuum evaporation), coating (dip coating, dye coating, rod coating, spin coating, spray coating), printing (inkjet, screen printing (porcelain printing), offset printing (lithography), flexographic printing (relief printing), gravure printing or micro-contact printing, etc.) and other methods.

[0622] The island-shaped layer (including the light-emitting layer) manufactured in the manufacturing method of the display device described below is not formed using a high-precision metal mask, but is formed by processing by photolithography after the light-emitting layer is deposited on the entire surface. Therefore, a high-definition display device or a display device with a high aperture ratio that has been difficult to achieve so far can be realized. Furthermore, since the light-emitting layer can be formed separately for each color, a display device with extremely clear, high contrast and high display quality can be realized. In addition, by providing a sacrificial layer on the light-emitting layer, the damage to the light-emitting layer during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting element can be improved.

[0623] For example, when a display device is composed of three light-emitting elements: a light-emitting element emitting blue light, a light-emitting element emitting green light, and a light-emitting element emitting red light, three island-shaped light-emitting layers can be formed by repeating the formation of the light-emitting layer and the photolithography process three times.

[0624] First, pixel electrodes 111R, 111G, 111B and a conductive layer 123 are formed on a substrate 151 provided with transistors 205R, 205G, 205B, etc. (not shown). Fig.29A ).

[0625] When forming the conductive film to be the pixel electrode, for example, a sputtering method or a vacuum evaporation method may be used. By forming a resist mask on the conductive film by a photolithography process and then processing the conductive film, the pixel electrodes 111R, 111G, 111B and the conductive layer 123 can be formed. The conductive film can be processed by one or both of a wet etching method and a dry etching method.

[0626] Next, a film 133Bf (which will later become a layer 133B) is formed on the pixel electrodes 111R, 111G, and 111B. Fig.29A ). The film 133Bf (latter layer 133B) includes a light-emitting layer that emits blue light.

[0627] This embodiment shows an example in which an island-shaped EL layer is first formed in a light-emitting element that emits blue light, and then an island-shaped EL layer is formed in a light-emitting element that emits light of other colors.

[0628] In the process of forming the island-shaped EL layer, the pixel electrodes in the light-emitting elements of the colors formed second and later may be damaged in the previous process. Therefore, the driving voltage of the light-emitting elements of the colors formed second and later may become high.

[0629] Therefore, when manufacturing a display device according to one embodiment of the present invention, it is preferred to start manufacturing from the island EL layer of the light-emitting element (e.g., the blue light-emitting element) that emits the shortest wavelength of light. For example, it is preferred to manufacture the island EL layer in the order of blue, green, red, or blue, red, green.

[0630] Thus, the state of the interface between the pixel electrode and the EL layer in the blue light-emitting element can be well maintained, thereby suppressing the driving voltage of the blue light-emitting element from becoming higher. In addition, the life of the blue light-emitting element can be extended and the reliability can be improved. Note that compared with the blue light-emitting element, the driving voltage rise of the red and green light-emitting elements is less affected, so the driving voltage can be reduced and the reliability can be improved as a whole display device.

[0631] Note that the order of manufacturing the island-shaped EL layers is not limited to the above order, and for example, the island-shaped EL layers may be manufactured in the order of red, green, and blue.

[0632] like Fig.29A As shown, the film 133Bf is not formed on the conductive layer 123. For example, the film 133Bf can be deposited only in a desired region using a range mask. By adopting a deposition process using a range mask and a processing process using a resist mask, a light emitting element can be manufactured with a relatively simple process.

[0633] The heat-resistant temperature of the compound contained in the film 133Bf is preferably 100° C. or more and 180° C. or less, more preferably 120° C. or more and 180° C. or less, and further preferably 140° C. or more and 180° C. or less. Thus, the reliability of the light-emitting element can be improved. In addition, the upper limit of the temperature that can be tolerated in the manufacturing process of the display device can be increased. Therefore, the range of selection of materials and formation methods for the display device can be expanded, thereby achieving an increase in yield and an increase in reliability.

[0634] As the heat-resistant temperature, for example, any of the glass transition temperature, softening point, melting point, thermal decomposition temperature and 5% weight loss temperature may be used, and the lowest temperature among the above temperatures is preferably used.

[0635] The film 133Bf can be formed by, for example, a vapor deposition method, specifically, a vacuum vapor deposition method. Alternatively, the film 133Bf can be formed by a transfer method, a printing method, an inkjet method, or a coating method.

[0636] Next, a sacrificial layer 118B is formed on the film 133Bf and the conductive layer 123 ( Fig.29A ). The sacrificial layer 118B can be formed by forming a resist mask on a film that will later become the sacrificial layer 118B by a photolithography process and then processing the film.

[0637] By providing the sacrificial layer 118B on the film 133Bf, damage to the film 133Bf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting element can be improved.

[0638] The sacrificial layer 118B is preferably provided in a manner covering each end of the pixel electrodes 111R, 111G, and 111B. Thus, the end of the layer 133B formed in the subsequent process is located outside the end of the pixel electrode 111B. Since the entire top surface of the pixel electrode 111B can be used as a light-emitting area, the aperture ratio of the pixel can be increased. In addition, the end of the layer 133B may be damaged in the process after the layer 133B is formed, so it is preferably located outside the end of the pixel electrode 111B, that is, it is preferably not used as a light-emitting area. Thus, the uneven characteristics of the light-emitting element can be suppressed, and the reliability can be improved.

[0639] In addition, by covering the top surface and side surfaces of the pixel electrode 111B with the layer 133B, each process after forming the layer 133B can be performed without exposing the pixel electrode 111B. When the end of the pixel electrode 111B is exposed, corrosion may occur in an etching process, etc. By suppressing the corrosion of the pixel electrode 111B, the yield and characteristics of the light-emitting element can be improved.

[0640] Furthermore, it is preferable that the sacrificial layer 118B is further provided at a position overlapping with the conductive layer 123. Thus, the conductive layer 123 can be prevented from being damaged during the manufacturing process of the display device.

[0641] As the sacrificial layer 118B, a film having high resistance to the processing conditions of the film 133Bf is used. Specifically, a film having a large etching selectivity ratio with the film 133Bf is used.

[0642] The sacrificial layer 118B is formed at a temperature lower than the heat resistance temperature of each compound included in the film 133Bf. The substrate temperature when forming the sacrificial layer 118B is typically 200°C or less, preferably 150°C or less, more preferably 120°C or less, further preferably 100°C or less, and further preferably 80°C or less.

[0643] When the heat-resistant temperature of the compound contained in the film 133Bf is high, the deposition temperature of the sacrificial layer 118B can be increased, so it is preferred. For example, the substrate temperature when forming the sacrificial layer 118B can also be set to above 100°C, above 120°C, or above 140°C. The higher the deposition temperature, the denser and more barrier-resistant inorganic insulating film can be formed. Therefore, by depositing the sacrificial layer at the above temperature, the damage to the film 133Bf can be further reduced, thereby improving the reliability of the light-emitting element.

[0644] The deposition temperature of other layers (eg, insulating film 125f) formed on the film 133Bf is the same as described above.

[0645] The sacrificial layer 118B may be formed by, for example, sputtering, ALD (including thermal ALD and PEALD), CVD, or vacuum evaporation. Alternatively, the sacrificial layer 118B may be formed by the above-mentioned wet deposition method.

[0646] The sacrificial layer 118B (a layer provided in contact with the film 133Bf when the sacrificial layer 118B has a stacked structure) is preferably formed by a formation method that causes less damage to the film 133Bf. For example, ALD or vacuum evaporation is more preferable than sputtering.

[0647] The sacrificial layer 118B can be processed by wet etching or dry etching. The sacrificial layer 118B is preferably processed by anisotropic etching.

[0648] By using the wet etching method, the damage to the film 133Bf during the processing of the sacrificial layer 118B can be reduced compared to the dry etching method. When the wet etching method is used, for example, it is preferred to use a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed solution containing two or more of the above. In addition, when the wet etching method is used, a mixed acid solution containing water, phosphoric acid, dilute hydrofluoric acid, and nitric acid can also be used. Note that the solution used for the wet etching process can be alkaline or acidic.

[0649] As the sacrificial layer 118B, for example, one or more of a metal film, an alloy film, a metal oxide film, a semiconductor film, an inorganic insulating film, and an organic insulating film can be used.

[0650] As the sacrificial layer 118B, for example, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium and tantalum, or alloy materials containing these metal materials can be used.

[0651] The sacrificial layer 118B can use metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), and indium tin oxide containing silicon.

[0652] Note that element M (M is one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used instead of the above-mentioned gallium.

[0653] For example, as a material very suitable for the manufacturing process of semiconductors, semiconductor materials such as silicon or germanium are preferably used. In addition, oxides or nitrides of the above semiconductor materials can be used. In addition, non-metallic materials such as carbon or their compounds can be used. In addition, metals such as titanium, tantalum, tungsten, chromium, aluminum, or alloys containing one or more of them can be used. In addition, oxides of the above metals such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride or tantalum nitride can be used.

[0654] In addition, various inorganic insulating films that can be used for the protective layer 131 can be used as the sacrificial layer 118B. In particular, the adhesion between the oxide insulating film and the film 133Bf is higher than the adhesion between the nitride insulating film and the film 133Bf, so it is preferred. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide and silicon oxide can be used for the sacrificial layer 118B. As the sacrificial layer 118B, for example, an aluminum oxide film can be formed by the ALD method. By using the ALD method, damage to the substrate (especially the film 133Bf) can be reduced, so it is preferred.

[0655] For example, the sacrificial layer 118B may have a stacked structure of an inorganic insulating film (eg, an aluminum oxide film) formed by ALD and an inorganic film (eg, an In—Ga—Zn oxide film, a silicon film, or a tungsten film) formed by sputtering.

[0656] In addition, the same inorganic insulating film can be used as both the sacrificial layer 118B and the insulating layer 125 formed later. For example, an aluminum oxide film formed using the ALD method can be used as both the sacrificial layer 118B and the insulating layer 125. Here, the sacrificial layer 118B and the insulating layer 125 can be deposited under the same deposition conditions or different deposition conditions. For example, by depositing the sacrificial layer 118B under the same conditions as ...

Claims

1. A semiconductor device comprising: Semiconductor layer; a first conductive layer; a second conductive layer; a third conductive layer; a fourth conductive layer; a first insulating layer; as well as The second insulating layer, wherein at least a portion of the second conductive layer contacts the top surface of the first conductive layer, The first insulating layer is located on the second conductive layer, The third conductive layer is located on the first insulating layer, The semiconductor layer is in contact with the top surface of the first conductive layer, the side surface of the second conductive layer, the third conductive layer and the side surface of the first insulating layer. The second insulating layer is located on the semiconductor layer, Furthermore, the fourth conductive layer is located on the second insulating layer and overlaps with the semiconductor layer via the second insulating layer.

2. A semiconductor device comprising: Semiconductor layer; a first conductive layer; a second conductive layer; a third conductive layer; a fourth conductive layer; a first insulating layer; as well as The second insulating layer, wherein the second conductive layer contacts the top surface of the first conductive layer and has a first opening reaching the first conductive layer, The first insulating layer is located on the second conductive layer and has a second opening overlapping the first opening. The third conductive layer is located on the first insulating layer and has a third opening overlapping the first opening and the second opening. The semiconductor layer contacts the top surface of the first conductive layer through the first opening to the third opening, and contacts the side surface of the second conductive layer in the first opening, the third conductive layer, and the side surface of the first insulating layer in the second opening. The second insulating layer is located on the semiconductor layer, Furthermore, the fourth conductive layer is located on the second insulating layer and overlaps with the semiconductor layer via the second insulating layer.

3. The semiconductor device according to claim 1 or 2, The shortest distance from the top surface of the first conductive layer to the top surface of the second conductive layer is longer than the shortest distance from the top surface of the first conductive layer to the bottom surface of the fourth conductive layer.

4. The semiconductor device according to claim 1 or 2, The conductivity of the second conductive layer is higher than that of the first conductive layer.

5. The semiconductor device according to claim 1 or 2, The semiconductor layer contacts the top surface and the side surface of the third conductive layer.

6. The semiconductor device according to claim 1 or 2, The semiconductor layer comprises a metal oxide.

7. The semiconductor device according to claim 1 or 2, wherein a metal oxide is included between the semiconductor layer and the second conductive layer, And the metal oxide includes the metal included in the second conductive layer.

8. A semiconductor device comprising: a first metal oxide layer; a second metal oxide layer; a first conductive layer; a second conductive layer; a third conductive layer; a fourth conductive layer; a first insulating layer; as well as The second insulating layer, wherein at least a portion of the second conductive layer contacts the top surface of the first conductive layer, The first insulating layer is located on the second conductive layer, The third conductive layer is located on the first insulating layer, The first metal oxide layer is in contact with the top surface of the first conductive layer, the side surface of the second metal oxide layer, the third conductive layer, and the side surface of the first insulating layer. The second metal oxide layer is in contact with a side surface of the second conductive layer, The second insulating layer is located on the first metal oxide layer, The fourth conductive layer is located on the second insulating layer and overlaps with the first metal oxide layer via the second insulating layer. Furthermore, the second metal oxide and the second conductive layer include the same metal element.

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