Indication device

Abstract

The present invention provides a highly flexible display device and a method for manufacturing the same. [Solution] A transistor comprising a translucent semiconductor film on a flexible substrate, A capacitive element in which a dielectric film is provided between the first electrode and the second electrode, and a semiconductor film covering the second electrode A dielectric film is formed with the first electrode. The capacitive element has a region where the first electrode and the dielectric film are in contact, and the The insulating film in 1 does not cover the region in question.

Description

Technical Field

[0001] The present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine , a manufacture, or a composition of matter. In particular , one aspect of the present invention relates to a semiconductor device, a light-emitting device, a display device, and methods for manufacturing them.

[0002] Note that in this specification and the like, the semiconductor device generally refers to any device that can function by utilizing semiconductor characteristics. For example, an electro-optical device, a display device, a light-emitting device, a semiconductor circuit, a transistor, and an electronic device may have a semiconductor device.

Background Art

[0003] In recent years, display devices such as liquid crystal display devices using liquid crystal elements as display elements and light-emitting display devices using light-emitting elements such as organic EL (electroluminescence, also referred to as organic light-emitting diodes, OLEDs, etc.) elements have become widely popular. Further, since these display devices can be made flexible, display devices using a flexible substrate have been studied. As a method for manufacturing a display device using a flexible substrate, after manufacturing a semiconductor element such as a thin-film transistor on a substrate such as a glass substrate or a quartz substrate, for example, an organic resin is filled between the semiconductor element and the substrate, and a technique for transposing the semiconductor element from the glass substrate or the quartz substrate to another substrate (for example, a flexible substrate) has been developed (Patent Document 1).

[0004] As a method for manufacturing a display device using a flexible substrate, after manufacturing a semiconductor element such as a thin-film transistor on a substrate such as a glass substrate or a quartz substrate, for example, an organic resin is filled between the semiconductor element and the substrate, and a technique for transposing the semiconductor element from the glass substrate or the quartz substrate to another substrate (for example, a flexible substrate) has been developed (Patent Document 1).

Prior Art Documents

Patent Documents

[0005] ​​​​ [Patent Document 1] Japanese Patent Publication No. 2003-174153 [Overview of the project] [Problems that the invention aims to solve]

[0006] One aspect of the present invention aims to provide a highly flexible display device and a method for manufacturing the same. One aspect of the present invention provides a crack-resistant display device and a method for manufacturing the same. One of the objectives is to provide a lightweight display device, and One of the objectives of this invention is to provide a method for manufacturing a flexible material. Alternatively, one aspect of this invention is to provide a flexible material. One of the objectives is to provide a display device and a method for manufacturing the same.

[0007] Alternatively, one aspect of the present invention provides a reliable display device and a method for manufacturing the same. This will be one of the challenges.

[0008] Alternatively, one aspect of the present invention aims to provide a novel display device and a method for manufacturing the same. This will be one of the issues. Note that the description of these issues does not preclude the existence of other issues. One aspect of the present invention does not require that all of these problems be solved. Other issues will become clear from the descriptions in the specification, drawings, claims, etc. Furthermore, it is possible to extract other issues from the descriptions in the specification, drawings, claims, etc. ru. [Means for solving the problem]

[0009] One aspect of the present invention relates to a transient comprising a translucent semiconductor film on a flexible substrate. A capacitive element in which a dielectric film is provided between the first electrode and the second electrode, and a semiconductor film The capacitive element has a covering insulating film, and the insulating film has a region where the first electrode and the dielectric film are in contact. This is a display device characterized by not covering the area in question.

[0010] One aspect of the present invention relates to a transient comprising a translucent semiconductor film on a flexible substrate. A capacitive element having a dielectric film provided between a first electrode and a second electrode, and a light-emitting element The capacitive element has a first insulating film covering a semiconductor film, and the first electrode and the dielectric film are in contact. The display device has a region, and the first insulating film does not cover the region.

[0011] The first electrode is formed on the same surface as the semiconductor film. The light-emitting element emits, for example, white light. It is possible to do so. Furthermore, it can be superimposed with a light-emitting element to form a colored layer.

[0012] The display device has a top emission structure, a bottom emission structure, or a dual-missile structure. It can be made into a simple structure. [Effects of the Invention]

[0013] The display device can be made more flexible. Furthermore, according to one aspect of the present invention, the bending motion is repeated. Because it is less prone to damage even when returned, it realizes a highly reliable display device. It is possible.

[0014] According to one aspect of the present invention, a highly flexible display device and a method for manufacturing the same are provided. can.

[0015] According to one aspect of the present invention, a reliable display device and a method for manufacturing the same are provided. It is possible.

[0016] According to one aspect of the present invention, a novel display device and a method for manufacturing the same can be provided. . [Brief explanation of the drawing]

[0017] [Figure 1] A perspective view illustrating one form of display device. [Figure 2] A cross-sectional view illustrating one form of a display device. [Figure 3] A block diagram and circuit diagram illustrating one form of a display device. [Figure 4] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 5] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 6] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 7] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 8] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 9] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 10] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 11] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 12] A cross-sectional view illustrating one method for manufacturing a display device. [Figure 13] A cross-sectional view illustrating one form of a display device. [Figure 14] A diagram illustrating one form of transistor. [Figure 15] A diagram illustrating one form of transistor. [Figure 16] A diagram illustrating one form of transistor. [Figure 17] A diagram illustrating the band structure of a transistor. [Figure 18] A diagram illustrating an example of a light-emitting element configuration. [Figure 19] A diagram illustrating an example of electronic equipment and lighting devices. [Figure 20] A diagram illustrating an example of an electronic device. [Figure 21] A cross-sectional view illustrating one form of a display device. [Figure 22] A cross-sectional view illustrating one form of a display device. [Figure 23] A cross-sectional view illustrating one form of a display device. [Figure 24] A cross-sectional view illustrating one form of a display device. [Modes for carrying out the invention]

[0018] Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. Without departing from the spirit and scope of the present invention, its form and details may be modified in various ways. It will be easily understood by those skilled in the art to obtain this. Therefore, the present invention is as shown in the embodiments below. The description is not to be interpreted as being limited to the stated content. The same reference numeral is used in common across different drawings for parts that are identical or have similar functions. I will omit the explanation of that repetition.

[0019] In the figures described herein, the size, layer thickness, or area of ​​each component is as follows: Details may be exaggerated or omitted to clarify the meaning. Therefore, the scale may not necessarily reflect the actual situation. It is not limited to the . In particular, in the top view, some components are used to make the drawing easier to understand. The description may be omitted in some cases.

[0020] Furthermore, the position, size, and scope of each component shown in the drawings, etc., are intended to facilitate understanding of the invention. Therefore, it may not represent the actual location, size, or range. For this reason, disclosure is required. The invention is not necessarily limited to the location, size, scope, etc. disclosed in the drawings, etc. For example. In the actual manufacturing process, the resist mask may be unintentionally damaged by processes such as etching. While this may result in a reduction in value, it is sometimes omitted for the sake of easier understanding.

[0021] Furthermore, especially in the top view (also called the "plan view"), in order to make the drawing easier to understand, In some cases, the description of certain components may be omitted.

[0022] Furthermore, in this specification, ordinal numbers such as "the first," "the second," etc., are used to avoid confusion of constituent elements. This is for visual inspection only and does not indicate any order or ranking, such as process order or layering order. Furthermore, even if an ordinal number is not attached to a term in this specification, the confusion of its constituent elements may occur. To avoid this, ordinal numbers may be used in the claims.

[0023] Furthermore, in this specification, the terms "electrode" and "wiring" do not limit the functionality of these components. It is not fixed. For example, "electrode" can be used as part of "wiring". The reverse is also true. Furthermore, the terms "electrode" and "wiring" can refer to multiple "electrodes" and "wiring". This also includes cases where the "lines" are formed as a single unit.

[0024] In this specification, the terms "above" and "below" refer to the relative positions of the constituent elements, specifically whether they are directly above or below. It is not limited to being below and in direct contact. For example, "electrode on insulating layer A" If the expression is "B", then it is not necessary for electrode B to be formed in direct contact with insulating layer A. Cases containing other components between marginal layer A and electrode B are not excluded.

[0025] Furthermore, the source and drain functions may differ when using transistors with different polarities, or when rotating In circuit operation, the direction of the current changes, and depending on the operating conditions, they can be swapped. Therefore, it is difficult to determine which is the source and which is the drain. In this specification, the terms source and drain may be used interchangeably. Let's assume that.

[0026] Furthermore, in this specification, "electrically connected" means "having some kind of electrical effect." This includes cases where the connection is made via ". Here, "something that has some electrical effect" The term "connection" is not particularly limited as long as it enables the exchange of electrical signals between connected objects. Therefore, even when expressed as "electrically connected," in actual circuits, In some cases, there is no logical connection point, and the wiring simply extends without any apparent purpose.

[0027] Furthermore, in this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. This refers to the state in which something is positioned. Therefore, it also includes cases where the angle is between -5° and 5°. "Right" and "orthogonal" refer to two straight lines that are positioned at an angle of 80° to 100°. It refers to a state or condition. Therefore, it also includes cases where the angle is between 85° and 95°.

[0028] Furthermore, in this specification, when an etching process is performed after a photolithography process, Unless otherwise specified, the resist mask formed in the photolithography process is It shall be removed after the finishing process is complete.

[0029] (Embodiment 1) In this embodiment, a semiconductor device and a method for manufacturing the same, which are aspects of the present invention, are described with reference to the drawings. Let me explain using this as an example. Figure 1(A) is a perspective view of the display device 100. The display device 100 is a light-emitting display device that uses a light-emitting element as a display element. The display device 100 illustrated in the diagram is flexible, as shown in Figures 1(B) and 1(C). It can be bent freely. Also, Figure 2 is shown in Figure 1(A) by the dashed line A1-A2. This is a cross-sectional view of the area.

[0030] <Display device configuration> The display device 100 illustrated in this embodiment includes a display area 131, a first drive circuit 132, and It has two drive circuits 133. Display area 131, first drive circuit 132, and second drive The drive circuit 133 is composed of multiple transistors. For example, the second drive circuit 1 33 is composed of multiple transistors 233. Also, the display device 100 is electric A light-emitting element 125 including pole 115, EL layer 117, and electrode 118, and terminal electrode 116 Multiple light-emitting elements 125 are formed within the display area 131. A transistor 231 (not shown) that controls the amount of light emitted by the light-emitting element 125 is electrically connected to it. They are connected. Also, the capacitor element 232 is electrically connected to the transistor 231. It is also a transistor that can supply data signals. 431 is electrically connected.

[0031] The first drive circuit 132 and the second drive circuit 133 are supplied from the external electrode 124 The function provides a signal to a specific light-emitting element 125 in the display area 131 at a specific timing. To possess.

[0032] Furthermore, the display device 100 is formed by bonding substrate 111 and substrate 121 via an adhesive layer 120. It has the following structure. An insulating film 205 is formed on the substrate 111 via an adhesive layer 112. The insulating film 205 is silicon oxide, silicon nitride, silicon oxide nitride, silicon oxide nitride Aluminum oxide, aluminum oxide nitride, or aluminum nitride oxide, etc., in a single layer Alternatively, it is preferable to form it in multiple layers. The insulating film 205 is formed by sputtering, CVD, or heat It can be formed using oxidation methods, coating methods, printing methods, etc.

[0033] Furthermore, the insulating film 205 functions as a base layer, and transitions from the substrate 111 and adhesive layer 112. This can prevent or reduce the diffusion of impurity elements into the star and light-emitting elements.

[0034] The substrates 111 and 121 are made of organic resin material or glass of a thickness that is flexible. Materials such as stainless steel can be used. The display device 100 has a so-called bottom emission structure (bottom surface If the display device is an injection-molded (injection-molded) or double-sided injection-molded (double-sided injection-molded) display device, the substrate 111 will have an EL (electroluminescent) element. A material that is transparent to light emitted from layer 117 is used. Also, the display device 100 is placed on the top surface In the case of an injection-type display device or a double-sided injection-type display device, the substrate 121 has an EL layer 1 A material that is transparent to light emitted from 17 is used.

[0035] Flexible and transparent to visible light can be used in substrates 121 and 111. The materials include polyethylene terephthalate resin and polyethylene naphthalate resin. Polyacrylonitrile resin, polyimide resin, polymethyl methacrylate resin, polycarbonate Carbonate resin, polyethersulfone resin, polyamide resin, cycloolefin resin These include polystyrene resin, polyamide-imide resin, and polyvinyl chloride resin. Examples of substrates that do not transmit light include stainless steel substrates and stainless steel foil. These include substrates with tungsten foil, tungsten substrates, and substrates with tungsten foil.

[0036] In addition, the substrates 121 and 111 are made of polypropylene, polyester, and polyfluorine. Vinyl chloride, polyvinyl chloride, polyamide, polyimide, inorganic vapor-deposited film, or paper, etc. It is possible to use cellophane substrates, stone substrates, wood substrates, cloth substrates (natural fibers) Fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester), regenerated fibers (A (including cete, cupro, rayon, recycled polyester), leather substrate, or rubber Circuit boards and other materials can also be used.

[0037] Furthermore, the thermal expansion coefficients of substrate 121 and substrate 111 are preferably 30 ppm / K or less. Furthermore, it is preferable to have a concentration of 10 ppm / K or less. Also, on the surface of substrate 121 and substrate 111 , pre-processed with films containing nitrogen and silicon, such as silicon nitride and silicon oxide nitride, and aluminum nitride, etc. A protective film with low water permeability, such as a film containing nitrogen and aluminum, may be deposited. , Substrates 121 and 111 are structures in which organic resin is impregnated into a fibrous material (so-called p You may also use a repreg (also known as a repreg).

[0038] By using such a substrate, it is possible to provide a display device that is less prone to cracking. This can provide a lightweight display device, or a flexible display device. It is possible.

[0039] Also, transistor 231, transistor 431, capacitive element 232, transistor 233 The terminal electrodes 116 and the surrounding electrodes are formed on the insulating film 205 (see Figure 2). In this configuration, transistors 431 and 233 form a channel. This is an example of a dual-gate transistor with a structure in which a semiconductor layer is sandwiched between two gate electrodes. However, transistors 431 and 233 are single-gated. It is also possible to use a t-type transistor. For example, transistor 431 and t Transistor 233 includes channel-protected transistors and top-gate type transistors. It is also possible to use characters such as "ta".

[0040] Furthermore, transistor 231, which is not shown in Figure 2, has the same structure as the other transistors. It is possible to do so. Also, transistor 231, transistor 431, and transistor 233 may have a similar structure or a different structure. The size of the transistor (e.g., channel length and channel width) varies depending on the transistor. You can adjust it as needed.

[0041] Transistors 431 and 233 have a gate electrode 206 and a gate insulating film 20 7. It has an oxide semiconductor film 208, a source electrode 209a, and a drain electrode 209b.

[0042] Furthermore, an insulating film 108 is formed on transistors 431 and 233, providing insulation. An insulating film 109 is formed on film 108, and an insulating film 110 is formed on insulating film 109. The insulating film 110 acts as a protective insulating layer, preventing transients from the layers above the insulating film 110. To prevent or reduce the diffusion of impurity elements into transistor 431 and transistor 233. It is possible.

[0043] Furthermore, in regions that do not overlap with transistors 431 and 233, the insulating film Parts of 108 and insulating film 109 have been removed. By removing it, the display device 100 can be made more flexible.

[0044] Furthermore, an insulating film 211 is formed on the insulating film 110. To reduce surface irregularities, the insulating film 211 may be subjected to a planarization treatment. , not particularly limited, polishing treatments (e.g., chemical mechanical polishing) This is done by chemical polishing (CMP) or dry etching. It is possible.

[0045] Furthermore, on the insulating film 211, there is a light-emitting element 125 and other light-emitting elements adjacent to the light-emitting element 125. A partition wall 114 is formed to separate 125.

[0046] Furthermore, the substrate 121 has a light-shielding film 264, a colored layer 266, and an overcoat layer 268. It is formed. The display device 100 uses the light 235 emitted from the EL layer 117 to illuminate the colored layer 2 A so-called top emission structure (top surface injection structure) in which material is ejected from the substrate 121 side via 66. It is a display device.

[0047] Furthermore, the light-emitting element 125 is made of insulating film 211, insulating film 110, insulating film 109, and insulating film 1 An opening in 08 is electrically connected to transistor 231 via wiring 241. It is being done.

[0048] Furthermore, the insulating film 211, insulating film 110, insulating film 109, and insulating film are superimposed on the terminal electrode 116. In the opening provided in the edge film 108, the external electrode 124 and the terminal electrode 116 are anisotropically conductive. They are electrically connected via the connecting layer 123. For example, the external electrode 124 is FP. C can be used.

[0049] The anisotropic conductive connecting layer 123 is a known anisotropic conductive film (ACF: Anisotropic c Conductive Film) or anisotropic conductive paste (ACP: Anisot It can be formed using materials such as ropic conductive paste.

[0050] The anisotropic conductive connecting layer 123 is a thermosetting, or thermosetting and photocurable resin with conductive particles. A mixture of paste-like or sheet-like materials that has been cured. Anisotropic conductive connecting layer Material 123 exhibits anisotropic conductivity through light irradiation or thermocompression bonding. Anisotropic conductive connecting layer The conductive particles used in 123 include, for example, spherical organic resins made of materials such as Au, Ni, and Co. Particles coated with a thin film of metal can be used.

[0051] The external electrode 124 and the terminal electrode 116 are electrically connected via the anisotropic conductive connecting layer 123. This makes it possible to input power and signals to the display device 100.

[0052] Furthermore, as shown in Figure 21, a touch sensor may be formed on the substrate 121. Various types of sensors can be used, including resistive, capacitive, and optical sensors. As shown in Figure 21, the touch sensor electrode 910a and the touch sensor electrode 910b are , connected via wiring 912. It does not come into contact with another touch sensor electrode 910c. To achieve this, an insulating layer 911 is provided on top of it. Touch sensor electrode 910 a, 910b, and 910c are made of indium tin oxide or indium zinc to allow light to pass through. It is preferable that it be formed of a transparent conductive film such as an oxide. Regarding the wiring 912, it is arranged as follows: Because the surface area is small, it has a non-transparent conductive material, such as Al, Mo, Ti, W, etc. It can be constructed using a single-layer film or a multilayer film. However, indium tin oxide and A transparent conductive film such as indium zinc oxide may be used. As shown in Figure 21, on the substrate 121 By directly forming the touch sensor, when the display device 100 is bent, the positional shift is corrected. It has the advantage of being less likely to cause problems.

[0053] Furthermore, optical sheets such as polarizing plates and phase difference plates may be provided on the substrate 121.

[0054] Furthermore, it is also possible to install touch sensors on substrates other than substrate 121. Figure 22 shows... An example of a case where a touch sensor is placed on a surface other than the substrate 121 is shown. One example is substrate 921. This is the outermost circuit board, and corresponds to the cover in the display device 100. The cover is operated by directly touching it with a human finger or stylus. In Figure 22, For example, a touch sensor is provided on the back of circuit board 921. Circuit board 921 and circuit board 121 Between them, an adhesive layer 920 is provided and fixed. The adhesive layer 920 is It can be formed from a similar material. This will prevent misalignment even when the display device 100 is bent. It has the advantage of being less prone to causing problems. Also, because there is no air layer in between, it is less likely to reflect external light. Therefore, it also has the advantage of improving visibility.

[0055] Note that when the display device 100 is bent, the substrate 921 is replaced with substrate 121 and substrate 11. It is desirable that it be formed from the same material as in 1. However, the display device 100 should be less prone to cracking. Taking advantage of this point, if the display device 100 is not used in a bent state, the substrate 921 is glass A substrate may be used. In particular, by using chemically treated tempered glass, it becomes scratch-resistant. This allows for the construction of robust display devices. For example, alkali aluminosilicate elements It is possible to use glass made of a specific material. Also, the display device 100 is bendable. Therefore, even if dropped, it is less likely to break, resulting in a durable display device. Yes, it's possible.

[0056] <Example of pixel circuit configuration> Next, a more specific configuration example of the display device 100 will be described using Figure 3. Figure 3(A ) is a block diagram illustrating the configuration of the display device 100. The display device 100 is a table It has a display area 131, a first drive circuit 132, and a second drive circuit 133. Circuit 132 functions, for example, as a scan line drive circuit. Also, the second drive circuit 133 is... For example, it functions as a signal line drive circuit.

[0057] Furthermore, the display devices 100 are arranged substantially parallel to each other and are driven by the first drive circuit 132. m scan lines 135 whose potential is controlled, and each of them is arranged substantially parallel to the second drive It has n signal lines 136 whose potential is controlled by circuit 133. Furthermore, the display area Region 131 has a plurality of pixels 134 arranged in a matrix. Also, the first drive circuit Sometimes, components 132 and the second drive circuit 133 are collectively referred to as the drive circuit section.

[0058] Each scan line 135 is one of the pixels 134 arranged in m rows and n columns in the display area 131. It is electrically connected to n pixels 134 arranged in any row. Also, each signal line 136 This refers to m pixels 134 arranged in m rows and n columns, where m pixels 134 are located in any of the columns. It is electrically connected to 4. m and n are both integers greater than or equal to 1.

[0059] Figures 3(B) and 3(C) are used for pixel 134 of the display device shown in Figure 3(A). This shows possible circuit configurations.

[0060] [An example of a pixel circuit for a light-emitting display device] Furthermore, the pixel 134 shown in Figure 3(B) consists of a transistor 431, a capacitive element 232, and a transistor It has an radiator 231 and a light-emitting element 125.

[0061] One of the source and drain electrodes of transistor 431 is connected to the distribution to which the data signal is applied. It is electrically connected to the line (hereinafter referred to as the signal line DL_n). Furthermore, transistor 431 The gate electrode provides electrical signals to the wiring to which the gate signal is applied (hereinafter referred to as scan line GL_m). It connects to the network.

[0062] Transistor 431 is either on or off, which affects the node of the data signal. It has a function to control writing to 435.

[0063] One of the pair of electrodes of the capacitive element 232 is connected to a wire to which a specific potential is supplied (hereinafter referred to as the potential supply wire). It is electrically connected to VL_a, and the other end is electrically connected to node 435. Furthermore, the source electrode and the other drain electrode of transistor 431 are electrically connected to node 435. It connects to the target.

[0064] Capacitive element 232 functions as a holding capacitor to hold the data written to node 435. It has.

[0065] One of the source and drain electrodes of transistor 231 is electrically connected to the potential supply line VL_a. They are connected precisely. Furthermore, the gate electrode of transistor 231 is electrically connected to node 435. Connected.

[0066] One of the anodes and cathodes of the light-emitting element 125 is electrically connected to the potential supply line VL_b. The other end is electrically connected to the source electrode and drain electrode of transistor 231. It can be done.

[0067] As the light-emitting element 125, for example, an organic electroluminescent element (also known as an organic EL element) (u) and the like can be used. However, the light-emitting element 125 is not limited to this, Inorganic EL elements made of inorganic materials may also be used.

[0068] Furthermore, a high power supply potential VDD is supplied to one of the potential supply lines VL_a and VL_b. On the other hand, a low power supply potential VSS is applied.

[0069] In the display device having pixels 134 shown in Figure 3(B), the first drive circuit 132 drives the pixels of each row 134 is selected sequentially, and transistor 431 is turned on to send the data signal to node 435. Write it down.

[0070] When data is written to node 435, the pixel 134 has transistor 431 turned off. This puts it into a holding state. Furthermore, depending on the potential of the data written to node 435, The amount of current flowing between the source electrode and drain electrode of the lampistor 231 is controlled, and the light-emitting element 125 emits light with brightness corresponding to the amount of current flowing through it. By doing this sequentially for each row, the image It can display an image.

[0071] [An example of a pixel circuit for a liquid crystal display device] The pixel 134 shown in Figure 3(C) consists of a liquid crystal element 432, a transistor 431, and a capacitive element 2 It has 32 and

[0072] The potential of one of the pair of electrodes of the liquid crystal element 432 is set appropriately according to the specifications of the pixel 134. The orientation state of the liquid crystal element 432 is set by the data written to node 436. Furthermore, one of the pairs of electrodes of the liquid crystal element 432 that each of the multiple pixels 134 has, The potential (common potential) may be applied. Also, one of the liquid crystal elements 432 for each row of pixels 134 A different potential may be applied to one of the paired electrodes.

[0073] For example, the driving method for a display device equipped with a liquid crystal element 432 may be TN mode, STN mode D, VA mode, ASM (Axially Symmetric Aligned Mi cro-cell) mode, OCB (Optically Compensated B irefringence) mode, FLC (Ferroelectric Liqui d Crystal) mode, AFLC (AntiFerroelectric Liq. uid Crystal) mode, MVA mode, PVA (Patterned Ver (Critical Alignment) mode, IPS mode, FFS mode, or TBA You may also use modes such as (Transverse Bend Alignment). In addition, as a method of driving the display device, there is also ECB (Electric Ally Controlled Birefringence) mode, PDLC (P Olymer Dispersed Liquid Crystal (PNLC) mode, (Polymer Network Liquid Crystal) mode, guest host There are modes such as St Mode. However, this is not limited to these, and various types of liquid crystal elements and their driving methods exist. Various materials can be used.

[0074] Furthermore, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent The liquid crystal element 432 may be configured in a further manner. The liquid crystal exhibiting the blue phase has a response speed of 1 msec or less. Because it is short and optically isotropic, orientation processing is unnecessary, and it has low field of view dependence. stomach.

[0075] Furthermore, display elements other than the light-emitting element 125 and the liquid crystal element 432 may be used as display elements. This is also possible. For example, as a display element, electrophoretic elements, electronic ink, electro Feeding elements, MEMS (Micro-Electro-Mechanical Systems), Digital Micromirror devices (DMD), DMS (Digital Microshutter), M IRASOL®, IMOD (Interference Modulation) element It is also possible to use methods such as those mentioned above.

[0076] In pixel 134 of row m, column n, the source electrode and drain electrode of transistor 431 One end is electrically connected to signal line DL_n, and the other end is electrically connected to node 436. The gate electrode of transistor 431 is electrically connected to scan line GL_m. Node 431, by being in an ON or OFF state, transmits data signals to node 436. It has a function to control writing.

[0077] One of the pair of electrodes of the capacitive element 232 is connected to a wiring (hereinafter referred to as the capacitance wire CL) to which a specific potential is supplied. The other end is electrically connected to node 436. Also, the liquid crystal element 4 The other electrode of the pair of electrodes 32 is electrically connected to node 436. Note that the potential of the capacitance line CL is The value is set appropriately according to the specifications of pixel 134. Capacitive element 232 is located at node 436. It functions as a storage capacity for retaining written data.

[0078] For example, in the display device having pixels 134 as shown in Figure 3(C), each is driven by the first drive circuit 132 The pixels 134 of each row are selected sequentially, and transistor 431 is turned on to send data to node 436. Write the T signal.

[0079] Pixel 134, for which a data signal has been written to node 436, has transistor 431 in the off state. This process puts the image into a held state. By doing this sequentially for each row, the image can be displayed.

[0080] <Example of manufacturing method> Next, an example of a method for manufacturing the display device 100 will be explained using the cross-sectional views in Figures 4 to 12. Figures 4 to 12 correspond to the cross-section of the display area 131 in Figure 2.

[0081] [Forms a delamination layer] First, a release layer 113 is formed on the element formation substrate 101 (see Figure 4(A)). The substrate 101 can be a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, A metal substrate or the like can be used. Furthermore, the heat resistance that can withstand the processing temperature of this embodiment is A plastic substrate may also be used.

[0082] Furthermore, the glass substrate can be, for example, aluminosilicate glass or aluminoborosilicate glass. Glass materials such as barium borosilicate glass are used. Furthermore, barium oxide ( By including a large amount of BaO, more practical heat-resistant glass can be obtained. In addition, crystallized glass You can use materials like lass.

[0083] The release layer 113 is made of tungsten, molybdenum, titanium, tantalum, niobium, nickel, and Balt, zirconium, ruthenium, rhodium, palladium, osmium, iridium, Elements selected from silicon, or alloy materials containing the elements, or chemicals containing the elements It can be formed using composite materials. Furthermore, these materials can be formed in single layers or laminates. This is possible. Furthermore, the crystalline structure of the exfoliation layer 113 can be amorphous, microcrystalline, or polycrystalline. It may also be the case that the release layer 113 is made of aluminum oxide, gallium oxide, zinc oxide, and Titanium oxide, indium oxide, indium tin oxide, indium zinc oxide, or In It can also be formed using metal oxides such as GaZnO(IGZO).

[0084] The release layer 113 can be formed by sputtering, CVD, coating, printing, etc. The coating methods include spin coating, droplet dispensing, and dispensing.

[0085] When forming the release layer 113 as a single layer, tungsten, molybdenum, or tungsten and It is preferable to use an alloy material containing molybdenum. Alternatively, the release layer 113 can be formed as a single layer. In that case, tungsten oxide or oxidized nitride, molybdenum oxide or oxide Using nitrides, or oxides or oxidized nitrides of alloys containing tungsten and molybdenum It is preferable to do so.

[0086] Furthermore, the release layer 113 may include, for example, a layer containing tungsten and a layer containing tungsten oxide. When forming a layered structure of multiple layers, an oxide insulating film is formed in contact with the tungsten-containing layer. As a result, tungsten oxide is formed at the interface between the tungsten-containing layer and the oxide insulating film. It may also be useful to utilize this method. In addition, the surface of the tungsten-containing layer may be subjected to thermal oxidation treatment, oxygen plastic treatment, etc. Tungsten oxides are removed by treatment with Zuma, ozonated water, or other highly oxidizing solutions. A layer may be formed.

[0087] In this embodiment, tungsten is formed as the release layer 113 by sputtering. .

[0088] [Forms the underlying layer] Next, an insulating film 205 is formed as a base layer on the release layer 113 (see Figure 4(A)). Edge film 205 is silicon oxide, silicon nitride, silicon oxide nitride, silicon oxide nitride, acid Aluminum oxide, aluminum oxide nitride, or aluminum nitride oxide, etc., in a single layer or It is preferable to form it in multiple layers. The insulating film 205 is formed by sputtering, CVD, or thermal oxidation. It can be formed using methods such as coating and printing.

[0089] The thickness of the insulating film 205 is 30 nm to 500 nm, preferably 50 nm to 400 nm. It should be less than or equal to m.

[0090] The insulating film 205 spreads impurity elements from the substrate 111 and adhesive layer 112 to the light-emitting element 125. Dispersion can be prevented or reduced. In this embodiment, the insulating film 205 is made of plasma A silicon oxide film with a thickness of 200 nm is formed by the CVD method.

[0091] [To form the gate] Next, a gate electrode 206 is formed on the insulating film 205 (see Figure 4(A)). 206 is made of aluminum, chromium, copper, tantalum, titanium, molybdenum, and tungsten. A selected metal element, or an alloy containing the above-mentioned metal elements, or the above-mentioned metal elements It can be formed using a combination of alloys, etc. Also, manganese, zirconium A metal element selected from one or more of these may be used. Also, the gate electrode 206 It may be a single-layer structure or a laminated structure of two or more layers. For example, an aluminum containing silicon A single-layer structure of a titanium film, a double-layer structure in which an aluminum film is laminated on a titanium film, and a titanium nitride film with a titanium film on top. Two-layer structure with stacked tungsten films, two-layer structure with stacked tungsten films on titanium nitride films, nitriding A two-layer structure consisting of a tungsten film laminated on a tantalum film or tungsten nitride film, and a titanium film. A two-layer structure with a copper film laminated on top, a titanium film, and an aluminum film laminated on top of the titanium film, Furthermore, there are three-layer structures in which a titanium film is formed on top of it. Also, aluminum, titanium, Selected from tantalum, tungsten, molybdenum, chromium, neodymium, and scandium A plain film, an alloy film made up of multiple films, or a nitride film may be used.

[0092] Furthermore, tetrahydrogen 206 contains indium tin oxide and indium acid containing tungsten oxide. Indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide The substance contains titanium dioxide, indium tin oxide, indium zinc oxide, and silicon oxide. Transparent conductive materials such as indium tin oxide can also be applied. A laminated structure of the above-mentioned light-transmitting conductive material and the above-mentioned metal element can also be used.

[0093] First, the electrode 205 is subjected to a method such as sputtering, CVD, or vapor deposition. A conductive film, which is 6, is laminated, and a resist mask is applied to the conductive film by a photolithography process. Form. Next, use a resist mask to etch a portion of the conductive film that will become the gate electrode 206. This process forms the gate electrode 206. At this time, other wiring and electrodes are also formed simultaneously. It is possible.

[0094] The conductive film can be etched using either the dry etching method or the wet etching method, or both. It may be used. Note that when etching is performed by the dry etching method, the resist mass Performing an ashing treatment before removing the mask makes it easier to remove the resist mask using a stripping solution. It can be done this way.

[0095] Furthermore, the gate electrode 206 may be formed by electroplating, printing, or inkjet instead of the above-mentioned formation method. It may also be formed by the jet method or other methods.

[0096] The thickness of the galvanic electrode 206 is 5 nm or more and 500 nm or less, more preferably 10 nm or more. The wavelength is 00 nm or less, more preferably 10 nm to 200 nm.

[0097] Furthermore, by forming the gate electrode 206 using a light-shielding conductive material, externally... This makes it difficult for the light to reach the oxide semiconductor film 208 from the gate electrode 206 side. As a result, fluctuations in the electrical characteristics of transistors caused by light irradiation can be suppressed.

[0098] [Forming a gate insulating film] Next, the gate insulating film 207 is formed (see Figure 4(A)). The gate insulating film 207 is, for example, For example, silicon oxide, silicon oxide nitride, silicon nitride, silicon oxide, aluminum oxide Aluminum, a mixture of aluminum oxide and silicon oxide, hafnium oxide, gallium oxide or A Ga-Zn-based metal oxide or similar material can be used, and it can be provided in a layered or single-layer configuration.

[0099] Furthermore, as the gate insulating film 207, hafnium silicate (HfSiO x ), nitrogen is added Hafnium silicate (HfSi x O y N z ), Nitrogen-added hafnium Minate (HfAl x O y N z ), hafnium oxide, yttrium oxide, etc. By using k-materials, gate leakage in transistors can be reduced. For example, silica oxidative nitride A layered structure of condensate and hafnium oxide may also be used.

[0100] The thickness of the gate insulating film 207 is 5 nm or more and 400 nm or less, more preferably 10 nm or more. The wavelength should be 300 nm or less, more preferably 50 nm to 250 nm.

[0101] The gate insulating film 207 can be formed by sputtering, CVD, vapor deposition, or other methods. .

[0102] The gate insulating film 207 is a silicon oxide film, a silicon oxide nitride film, or silicon oxide nitride film. When forming a film, depositing gases containing silicon and oxidizing gases are used as raw material gases. It is preferable that it be present. Typical examples of silicon-containing sedimentary gases include silane, disilane, Examples include trisilane and silane fluoride. Oxidizing gases include oxygen, ozone, and nitrous oxide. Examples include nitrogen dioxide, etc.

[0103] Furthermore, the gate insulating film 207 consists of a nitride insulating film and an oxide insulating film, arranged sequentially from the gate electrode 206 side. A laminated structure in which layers are stacked may also be used. By providing a nitride insulating film on the gate electrode 206 side, Impurities from the gate electrode 206 side, typically hydrogen, nitrogen, alkali metals, or aluminum This prevents potassium earth metals and the like from migrating to the oxide semiconductor film 208. By providing an oxide insulating film on the semiconductor film 208 side, the gate insulating film 207 and the oxide semiconductor It is possible to reduce defect levels at the interface of film 208. As a result, the deterioration of electrical properties is reduced. A transistor with low carbonation can be obtained. Furthermore, as an oxide insulating film, a stoichiometric combination When formed using an oxide insulating film containing more oxygen than the required oxygen level, the gate insulating film It is possible to further reduce the defect levels at the interface between 207 and the oxide semiconductor film 208. Therefore, it is preferable.

[0104] Furthermore, if the gate insulating film 207 is made of a laminate of nitride insulating film and oxide insulating film as described above... In addition, it is preferable to make the nitride insulating film thicker than the oxide insulating film.

[0105] Because nitride insulating films have a higher relative permittivity than oxide insulating films, the thickness of the gate insulating film 207 is Even when thickened, the electric field generated at the gate electrode 206 is efficiently transmitted to the oxide semiconductor film 208. This can be achieved. In addition, by making the entire gate insulating film 207 thicker, the insulating properties of the gate insulating film 207 can be increased. This allows for increased edge breakdown voltage, thereby improving the reliability of semiconductor devices.

[0106] Furthermore, the gate insulating film 207 is a first nitride insulating film with few defects and hydrogen blocking properties A second nitride insulating film with high density and an oxide insulating film are stacked in order from the gate electrode 206 side. A laminated structure can be formed. The gate insulating film 207 has a first nitride insulating film with few defects. By using a film, the dielectric breakdown voltage of the gate insulating film 207 can be improved. By providing a second nitride insulating film with high hydrogen blocking properties to the first insulating film 207, Hydrogen contained in the electrode 206 and the first nitride insulating film moves to the oxide semiconductor film 208. This can prevent that from happening.

[0107] An example of a method for fabricating the first nitride insulating film and the second nitride insulating film is shown below. First, By using a plasma CVD method with a mixed gas of ranun, nitrogen, and ammonia as the source gas A silicon nitride film with few defects is formed as the first nitride insulating film. Next, the source gas is Switching to a mixed gas of silane and nitrogen, the hydrogen concentration is low and hydrogen is blocked. A silicon nitride film capable of such formation is formed as a second nitride insulating film. Depending on the method, a nitride insulating film with few defects and hydrogen blocking properties is laminated. A gate insulating film 207 can be formed.

[0108] Furthermore, the gate insulating film 207 is a third nitride insulating film with high impurity blocking properties, and A first nitride insulating film with few defects, a second nitride insulating film with high hydrogen blocking properties, and acid A laminated structure can be formed in which the oxide insulating film and the electrode are stacked sequentially from the gate electrode 206 side. A third nitride insulating film with high impurity blocking properties is provided on the gate insulating film 207. Therefore, impurities from gate electrode 206, typically hydrogen, nitrogen, alkali metals, or This prevents earth metals such as rutile from migrating to the oxide semiconductor film 208.

[0109] An example of a method for fabricating the first to third nitride insulating films is shown below. First, By plasma CVD using a mixed gas of silane, nitrogen, and ammonia as the raw material gas Therefore, a silicon nitride film with high impurity blocking properties is formed as a third nitride insulating film. Next, by increasing the ammonia flow rate, the silicon nitride film with fewer defects is processed in the first nitrogen It is formed as a phosphate insulating film. Next, the source gas is switched to a mixed gas of silane and nitrogen. A silicon nitride film with a low hydrogen concentration and capable of blocking hydrogen is used as the second... It is formed as a nitride insulating film. This formation method results in fewer defects and fewer impurities. A gate insulating film 207 is formed by stacking a nitride insulating film having blocking properties. can.

[0110] Furthermore, when forming a gallium oxide film as the gate insulating film 207, MOCVD (Meta Using the Organic Chemical Vapor Deposition method It can be formed by [doing something].

[0111] Furthermore, the oxide semiconductor film 208 on which the transistor channel is formed and hafnium oxide The insulating film containing the hafnium oxide is stacked via an oxide insulating film, and electrons are injected into the insulating film containing hafnium oxide. This allows you to change the threshold voltage of the transistor.

[0112] [Forms an oxide semiconductor film] Next, the oxide semiconductor film 208 in which the channel is formed, and later one electrode of the capacitive element 232 An oxide semiconductor film 209 that functions as such is formed on the gate insulating film 207 (see Figure 4(B)). (Illuminate.) Typical examples of oxide semiconductor films 208 and 209 are In -Ga oxide, In-Zn oxide, In-M-Zn oxide (M is Al, Ga, Y, Zr, La, Ce, or Nd) can be used.

[0113] When the oxide semiconductor film 208 is In-M-Zn oxide, when the sum of In and M is 1 00 atomic%, the atomic ratio of In to M is preferably such that In is 25 ato mic% or more and M is less than 75 atomic%, more preferably, In is 34 atomi c% or more and M is less than 66 atomic%.

[0114] In particular, the oxide semiconductor film 208 has an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more. Thus, by using an oxide semiconductor with a wide energy gap the off-current of the transistor can be reduced.

[0115] The thicknesses of the oxide semiconductor film 208 and the oxide semiconductor film 209 are 3 nm or more and 200 nm or less preferably 3 nm or more and 100 nm or less, more preferably 3 nm or more and 50 nm or less.

[0116] When the oxide semiconductor film 208 and the oxide semiconductor film 209 are In-M-Zn oxide (M is Al, Ga, Y, Zr, La, Ce, or Nd), the atomic ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In≧M and Zn>M. As such an atomic ratio of the metal elements of the sputtering target In:M:Zn = 1:1:1, In:M:Zn = 5:5:6, In:M:Zn = 2:1 :2, In:M:Zn = 3:1:2 are preferred. The formed oxide semiconductor film 208 ​​The atomic ratio of the oxide semiconductor film 209 includes fluctuations of plus or minus 40% of the atomic ratio of the metal elements contained in the above sputtering target as an error. Incidentally, when the content of In contained in the oxide semiconductor film 208 is large, the on-current of the transistor increases, and the field-effect mobility increases. Therefore, by forming the oxide semiconductor film 208 using a sputtering target of In-M-Zn oxide with an atomic ratio of metal elements of In:M:Zn = 3:1:2, a transistor with excellent electrical characteristics can be fabricated. The oxide semiconductor film 208 is formed using an oxide semiconductor film having a low carrier density. For example, the carrier density of the oxide semiconductor film 208 is 1×10 or less, preferably 1× 10 or less, more preferably 1×10 or less, and even more preferably 1×10

[0117] or less. Hereinafter, an oxide semiconductor film having a carrier density of 1×10 or less is preferably used. Incidentally, the present invention is not limited to these, and an appropriate composition may be used according to the semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the required transistor. Further, in order to obtain the semiconductor characteristics of the required transistor, it is preferable that the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, etc. of the oxide semiconductor film 208 are appropriate. 17 per cm 3 or less, preferably 1× 10 15 per cm 3 or less, more preferably 1×10 13 per cm 3 or less, and even more preferably 1×10 11 per cm 3 or less.

[0118] Note that the present invention is not limited to these, and an appropriate composition may be used according to the semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the required transistor. Further, in order to obtain the semiconductor characteristics of the required transistor, it is preferable that the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, etc. of the oxide semiconductor film 208 are appropriate. Note that the present invention is not limited to these, and an appropriate composition may be used according to the semiconductor characteristics and electrical characteristics (field-effect mobility, threshold voltage, etc.) of the required transistor. Further, in order to obtain the semiconductor characteristics of the required transistor, it is preferable that the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, etc. of the oxide semiconductor film 208 are appropriate. In addition, in order to obtain the semiconductor characteristics of the required transistor, it is preferable that the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, etc. of the oxide semiconductor film 208 are appropriate. In addition, in order to obtain the semiconductor characteristics of the required transistor, it is preferable that the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, etc. of the oxide semiconductor film 208 are appropriate. Note that the oxide semiconductor film 208 preferably has a low impurity concentration and a low defect level density.

[0119] Note that the oxide semiconductor film 208 preferably has a low impurity concentration and a low defect level density. By using a body membrane, it is possible to fabricate transistors with even better electrical properties. This is preferable. Here, the impurity concentration is low and the defect level density is low (few oxygen vacancies). This is called "high-purity genuine" or "substantially high-purity genuine." Oxide semiconductors, being highly intrinsic, have few carrier sources, thus allowing for a lower carrier density. In some cases, this can occur. Therefore, when a channel region is formed in the oxide semiconductor film, A zistor exhibits an electrical characteristic where the threshold voltage is negative (also known as normally-on). In some cases, this is rare. Also, high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors Body membranes have a low defect level density, which can sometimes result in a low trap level density.

[0120] Furthermore, a high-purity intrinsic or substantially high-purity intrinsic acid is used in the semiconductor film in which the channel is formed. Transistors using ionized semiconductor films have remarkably low off-current and a channel width of 1 × 10⁻⁶. 6 Even in a transistor with a channel length L of 10 μm, the source electrode and drain electrode When the voltage between them (drain voltage) is in the range of 1V to 10V, the off-current is the semiconductor parameter Below the measurement limit of the DATA analyzer, i.e., 1 × 10⁻⁶ -13 The ability to obtain the characteristic of being A or less Yes, it is possible. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film is electrically Oxide semiconductors can sometimes produce transistors with small variations in characteristics and high reliability. Charges trapped in the membrane's trap levels take a long time to disappear, almost as if they were fixed. It can behave like an electric charge. Therefore, in oxide semiconductor films with a high trap level density... Transistors in which a channel region is formed may have unstable electrical properties. Examples include hydrogen, nitrogen, alkali metals, or alkaline earth metals.

[0121] Hydrogen contained in oxide semiconductor films reacts with oxygen bonded to metal atoms to form water, and also acid An oxygen vacancy is formed in the lattice where an element has been removed (or in the area where oxygen has been removed). The presence of hydrogen can sometimes generate electrons, which act as carriers. Additionally, some of the hydrogen can turn gold. By bonding with oxygen atoms that bond with other atoms in the group, it can generate electrons, which act as carriers. Therefore, transistors using oxide semiconductors containing hydrogen exhibit normally-on characteristics. It's easy to understand.

[0122] Therefore, it is preferable that the oxide semiconductor film 208 has as little hydrogen as possible. Specifically, in oxide semiconductor film 208, secondary ion mass spectrometry (SIMS:Seco The hydrogen concentration obtained by (ndary ion mass spectrometry) , 2×10 20 atoms / cm 3 The following is preferably 5 × 10 19 atoms / cm 3 Below Below, fer 1 × 10 19 atoms / cm 3 Below, 5 x 10 18 ate / c m 3 The following is preferably 1 × 10 18 atoms / cm 3 The following is more preferable: 5 x 10 1 7 atoms / cm 3 More preferably 1 × 10 16 atoms / cm 3 The following ru.

[0123] When the oxide semiconductor film 208 contains silicon or carbon, which is one of the Group 14 elements, oxygen vacancies increase in the oxide semiconductor film 208, resulting in n-type conversion. Therefore, the concentration of silicon or carbon in the oxide semiconductor film 208 (the concentration obtained by secondary ion mass spectrometry) shall be 2×10 18 atoms / cm 3 or less, preferably 2×10 17 atoms / cm 3 or less.

[0124] In addition, in the oxide semiconductor film 208, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry shall be 1×10 18 atoms / cm 3 or less, preferably 2×10 16 atoms / cm 3 or less. Alkali metals and alkaline earth metals may generate carriers when combined with the oxide semiconductor, which may increase the off-current of the transistor. Therefore, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the oxide semiconductor film 208.

[0125] In addition, when the oxide semiconductor film 208 contains nitrogen, electrons, which are carriers, are generated, the carrier density increases, and n-type conversion becomes easy. As a result, a transistor using an oxide semiconductor containing nitrogen tends to have normally-on characteristics. Therefore, in the oxide semiconductor film, it is preferable that nitrogen is reduced as much as possible. For example, the nitrogen concentration obtained by secondary ion mass spectrometry shall be 5×10 18 atoms / cm 3 or less.

[0126] The structure of oxide semiconductor films will be described below.

[0127] Oxide semiconductor films are broadly classified into non-single-crystal oxide semiconductor films and single-crystal oxide semiconductor films. A single-crystal oxide semiconductor film is a CAAC-OS (C Axis Aligned Crystals Polycrystalline oxide semiconductor film This refers to microcrystalline oxide semiconductor films, amorphous oxide semiconductor films, etc.

[0128] First, let's explain the CAAC-OS membrane.

[0129] CAAC-OS film is an oxide semiconductor film having multiple c-axis oriented crystalline regions.

[0130] CAAC-OS film is scanned using a transmission electron microscope (TEM). When observed with a microscope, clear boundaries between crystalline regions, i.e., bonds, can be seen. The grain boundaries (also called crystal grain boundaries) cannot be identified. Therefore, CA AC-OS films are less susceptible to the decrease in electron mobility caused by grain boundaries.

[0131] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). ) This confirms that metal atoms are arranged in layers in the crystalline region. Each layer has irregularities on the surface (also called the surface to be formed) or the upper surface that forms the CAAC-OS film. The shape reflects this, and the elements are arranged parallel to the surface or top surface of the CAAC-OS film.

[0132] On the other hand, the CAAC-OS film was observed by TEM from a direction roughly perpendicular to the sample surface (planar TEM). (M observation) In the crystalline region, metal atoms are arranged in a triangular or hexagonal shape. This can be confirmed. However, no regularity is observed in the arrangement of metal atoms between different crystalline regions. stomach.

[0133] Furthermore, when electron diffraction is performed on the CAAC-OS film, oriented spots (bright spots) appear. It is observed.

[0134] Cross-sectional TEM observation and planar TEM observation revealed that the crystalline portion of the CAAC-OS film exhibits orientation. You can tell they are there.

[0135] Furthermore, most of the crystalline parts contained in the CAAC-OS film are cubes with sides less than 100 nm long. It is small enough to fit inside. Therefore, the crystalline portion contained in the CAAC-OS film has a side length of 10n. This also includes cases that fit within a cube smaller than m, smaller than 5 nm, or smaller than 3 nm. Furthermore, multiple crystalline regions contained in the CAAC-OS film are linked together, forming one large crystalline region. This can sometimes form. For example, in a planar TEM image, at 2500 nm 2 Above 5μm 2 or greater than 1000 μm 2 In some cases, crystal regions exceeding the above size may be observed.

[0136] X-ray diffraction (XRD) applied to the CAAC-OS film. When structural analysis is performed using this method, for example, a CAAC-OS film having InGaZnO4 crystals is found. In the out-of-plane analysis, the diffraction angle (2θ) shows a peak near 31°. This peak may appear. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have c-axis orientation, and the c-axis is generally aligned with the surface to be formed or the upper surface. It can be confirmed that it is facing in a nearly vertical direction.

[0137] On the other hand, in-pl X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In analysis using the ANE method, a peak may appear when 2θ is around 56°. This peak is It is attributed to the (110) plane of the InGaZnO4 crystal. Single crystal oxidation of InGaZnO4 For a solid semiconductor film, fix 2θ to around 56°, and use the normal vector of the sample surface as the axis (φ axis). When the sample is rotated while the analysis (φ scan) is performed, the crystal plane equivalent to the (110) plane is found. Six attributed peaks are observed. In contrast, in the case of the CAAC-OS film, 2θ is set to 5 Even when fixed at approximately 6° and scanned using the φ scan function, no clear peak appears.

[0138] From the above, it can be concluded that in CAAC-OS films, the orientation of the a-axis and b-axis is inconsistent between different crystalline regions. It is a rule, but it has c-axis orientation and the c-axis is parallel to the normal vector of the surface to be formed or the upper surface. It can be seen that it is facing in a certain direction. Therefore, it is arranged in layers as confirmed by the aforementioned cross-sectional TEM observation. Each layer of arranged metal atoms is a plane parallel to the ab-plane of the crystal.

[0139] The crystalline portion is formed when the CAAC-OS film is deposited, or when crystallization treatment such as heat treatment is performed. It is formed when this occurs. As mentioned above, the c-axis of the crystal is the surface on which the CAAC-OS film is formed or It is oriented in a direction parallel to the normal vector of the upper surface. Therefore, for example, the shape of the CAAC-OS film When the shape is altered by etching or other means, the c-axis of the crystal becomes the surface on which the CAAC-OS film is formed. Alternatively, it may not be parallel to the normal vector of the top surface.

[0140] Furthermore, the distribution of c-axis oriented crystalline regions within the CAAC-OS film does not need to be uniform. For example, the crystalline portion of the CAAC-OS film is formed by crystal growth from near the top surface of the CAAC-OS film. When formed in this way, the region near the top surface has a more c-axis oriented crystalline structure than the region near the surface being formed. The proportion of impurities can increase. Also, when impurities are added to the CAAC-OS film, The region to which the substance is added is altered, and regions with a different proportion of partially c-axis-oriented crystals are formed. Sometimes that happens.

[0141] Furthermore, the out-of-plane method for CAAC-OS films containing InGaZnO4 crystals. Analysis revealed that in addition to a peak near 2θ = 31°, a peak also appeared near 2θ = 36°. In some cases, this may occur. Peaks near 36° 2θ indicate c-axis orientation in a portion of the CAAC-OS film. This indicates that it contains crystals that do not have [the specified characteristic]. The CAAC-OS film has 2θ near 31°. It is preferable that a peak is observed, and that no peak is observed near 36° for 2θ.

[0142] CAAC-OS films are oxide semiconductor films with low impurity concentrations. The impurities include hydrogen, carbon, These are elements other than silicon and transition metal elements, which are the main components of oxide semiconductor films. In particular, silicon Elements such as ions, which have a stronger bonding force with oxygen than the metal elements that make up oxide semiconductor films, By removing oxygen from the material semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. This is a contributing factor. Also, heavy metals such as iron and nickel, argon, and carbon dioxide have a certain atomic radius. Because of its large molecular radius, when it is contained within an oxide semiconductor film, the oxide semiconductor film This disrupts the atomic arrangement and reduces crystallinity. Furthermore, these impurities are present in oxide semiconductor films. Objects can sometimes act as carrier traps or carrier sources.

[0143] Furthermore, CAAC-OS films are oxide semiconductor films with a low defect level density. For example, oxide Oxygen vacancies in semiconductor films can act as carrier traps or capture hydrogen. It can be a source of carrier activity.

[0144] A low impurity concentration and low defect level density (few oxygen vacancies) is referred to as high-purity intrinsic or This is essentially called high-purity intrinsic. High-purity intrinsic or substantially high-purity intrinsic oxide semiconductor film Because there are fewer carrier sources, the carrier density can be kept low. Transistors using oxide semiconductor films exhibit electrical characteristics where the threshold voltage is negative (no Also called Marion.) It rarely becomes high-purity genuine or substantially high-purity genuine. Oxide semiconductor films, being of a certain nature, have few carrier traps. Therefore, the oxide semiconductor film Transistors using this technology exhibit less variation in electrical characteristics and are highly reliable. Furthermore, the time required to release the charge trapped in the carrier trap of the oxide semiconductor film is [time]. The interval is long, and it can behave as if it were a fixed charge. Therefore, the impurity concentration is high. Transistors using oxide semiconductor films with a high defect level density exhibit unstable electrical properties. There are cases where this is the case.

[0145] Furthermore, transistors using CAAC-OS films exhibit electrical characteristics under irradiation with visible light and ultraviolet light. The fluctuations are small.

[0146] Next, we will explain polycrystalline oxide semiconductor films.

[0147] In polycrystalline oxide semiconductor films, crystal grains can be identified by TEM observation. The crystal grains contained in the crystalline oxide semiconductor film are, for example, 2 nm or larger and 30 nm or larger, as observed by TEM. The particle size must be 0 nm or less, 3 nm to 100 nm, or 5 nm to 50 nm. There are many of them. Also, grain boundaries can be confirmed in polycrystalline oxide semiconductor films using TEM observation images. There are cases where this is the case.

[0148] A polycrystalline oxide semiconductor film has multiple crystal grains, and the crystal orientation between these multiple crystal grains There may be differences. Also, when a polycrystalline oxide semiconductor film is constructed using an XRD device, When fabrication analysis is performed, for example, the out of a polycrystalline oxide semiconductor film having InGaZnO4 crystals -In the analysis using the -of-plane method, there is a peak near 31° for 2θ and a peak near 36° for 2θ. A peak, or other peaks, may appear.

[0149] Polycrystalline oxide semiconductor films may have high electron mobility due to their high crystallinity. Therefore, transistors using polycrystalline oxide semiconductor films have high field-effect mobility. However, polycrystalline oxide semiconductor films may have impurities segregated at the grain boundaries. In crystalline oxide semiconductor films, the grain boundaries become defect levels. In polycrystalline oxide semiconductor films, the grain boundaries are Because they can act as carrier traps or carrier sources, polycrystalline oxide semiconductor films are used. The transistors used showed less variation in electrical characteristics compared to transistors using CAAC-OS film. This can result in large, unreliable transistors.

[0150] Next, we will explain microcrystalline oxide semiconductor films.

[0151] In microcrystalline oxide semiconductor films, the crystalline regions can be clearly observed in TEM images. In some cases, this may not be the case. The crystalline portion contained in the microcrystalline oxide semiconductor film is between 1 nm and 100 nm in size. or are often between 1 nm and 10 nm in size. In particular, between 1 nm and 10 nm The following are nanocrystals (nc: nanocryst), which are microcrystalline structures between 1 nm and 3 nm in size. An oxide semiconductor film having al) is made nc-OS (nanocrystalline Ox It is called an IDE Semiconductor film. Also, an nc-OS film is, for example, TE In some cases, grain boundaries may not be clearly visible in images observed using M.

[0152] nc-OS films are used in minute regions (for example, regions between 1 nm and 10 nm, especially regions larger than 1 nm). The atomic arrangement has periodicity in the region of 3 nm or less. Also, the nc-OS film is different No regularity in crystal orientation is observed between the crystalline regions. Therefore, no orientation is observed throughout the film. In some cases, nc-OS films are indistinguishable from amorphous oxide semiconductor films depending on the analytical method. There are cases where XRD equipment using X-rays with a diameter larger than that of the crystalline region is used on nc-OS films. When structural analysis is performed using this method, the out-of-plane method reveals the crystal planes. No peaks are detected. Also, for nc-OS films, the probe diameter is larger than that of the crystalline region. For example, electron diffraction (also called limited-field electron diffraction) using an electron beam of 50 nm or more. When this is done, a diffraction pattern resembling a halo pattern is observed. On the other hand, for nc-OS films... , probe diameter close to or smaller than the size of the crystal (for example, 1 nm to 30 nm) When electron diffraction (also called nanobeam electron diffraction) is performed using an electron beam, the spot This is observed. Furthermore, when nanobeam electron diffraction is performed on the nc-OS film, it appears to trace a circle. In some cases, a region of high brightness (ring-shaped) may be observed in relation to the nc-OS film. When performing electron diffraction, multiple spots may be observed within a ring-shaped region. ru.

[0153] nc-OS films are oxide semiconductor films with higher orderliness than amorphous oxide semiconductor films. Therefore, nc-OS films have a lower defect level density than amorphous oxide semiconductor films. However, In nc-OS films, no regularity is observed in the crystal orientation between different crystalline regions. Therefore, nc-O The S film has a higher defect level density compared to the CAAC-OS film.

[0154] Therefore, nc-OS films may have a higher carrier density compared to CAAC-OS films. Oxide semiconductor films with high carrier density may have high electron mobility. Therefore, Transistors using nc-OS films may have high field-effect mobility. Because nc-OS films have a higher defect level density compared to CAAC-OS films, carrier traps The number of particles may increase. Therefore, transistors using nc-OS films are CAAC-O Compared to transistors using S film, these transistors exhibit greater variation in electrical characteristics and are less reliable. This is the result. However, nc-OS films can be formed even if they contain a relatively large amount of impurities. Therefore, it is easier to form than CAAC-OS films and can be suitably used depending on the application. This is possible in some cases. Therefore, semiconductor equipment having transistors using nc-OS films In some cases, the installation can be done with high productivity.

[0155] Next, we will explain amorphous oxide semiconductor films.

[0156] Amorphous oxide semiconductor films have an irregular atomic arrangement within the film and do not contain crystalline regions. These are physical semiconductor films. One example is an oxide semiconductor film that has an amorphous state, such as quartz.

[0157] In amorphous oxide semiconductor films, crystalline regions cannot be observed in TEM images.

[0158] When structural analysis of amorphous oxide semiconductor films is performed using an XRD device, out-of-p Analysis using the Lane method did not detect any peaks indicating crystal planes. Furthermore, amorphous oxide semi-crystalline materials were found. When electron diffraction is performed on a conductive film, a halo pattern is observed. Furthermore, amorphous oxides... When nanobeam electron diffraction is performed on a semiconductor film, no spots are observed, and a halo pattern is formed. N is observed.

[0159] Amorphous oxide semiconductor films are oxide semiconductor films that contain high concentrations of impurities such as hydrogen. Furthermore, amorphous oxide semiconductor films are oxide semiconductor films with a high defect level density.

[0160] Oxide semiconductor films with high impurity concentrations and high defect level densities are prone to carrier traps and carriers. It is an oxide semiconductor film with many sources of emission.

[0161] Therefore, amorphous oxide semiconductor films have an even higher carrier density compared to nc-OS films. This can sometimes happen. Therefore, transistors using amorphous oxide semiconductor films are normally... It tends to have the electrical characteristics of a normal-on transistor. Therefore, transistors that require the electrical characteristics of a normally-on transistor It may be suitable for use in certain applications. Amorphous oxide semiconductor films have a high defect level density. Therefore, carrier traps may increase. Compared to transistors using CAAC-OS film or nc-OS film, these transistors have a different electrical performance. The transistor exhibits large variations in its thermal characteristics, resulting in low reliability.

[0162] Next, we will explain single-crystal oxide semiconductor films.

[0163] Single-crystal oxide semiconductor films have low impurity concentrations and low defect level density (few oxygen vacancies). It is an oxide semiconductor film. Therefore, the carrier density can be lowered. Transistors using crystalline oxide semiconductor films rarely exhibit normally-on electrical characteristics. Furthermore, single-crystal oxide semiconductor films have a low impurity concentration and a low defect level density, so Rear trapping may be reduced. Therefore, transients using single-crystal oxide semiconductor films This results in a transistor with minimal variation in electrical characteristics and high reliability.

[0164] Furthermore, oxide semiconductor films have a higher density when they have fewer defects. Also, oxide semiconductor films are bonded Higher crystallinity results in higher density. Also, oxide semiconductor films have lower concentrations of impurities such as hydrogen. The density increases. Single-crystal oxide semiconductor films have a higher density than CAAC-OS films. Also, CAAC-OS films have a higher density than microcrystalline oxide semiconductor films. Body films have a higher density than microcrystalline oxide semiconductor films. Also, microcrystalline oxide semiconductor films are amorphous. It has a higher density than a sodium oxide semiconductor film.

[0165] Note that oxide semiconductor films include, for example, amorphous oxide semiconductor films, microcrystalline oxide semiconductor films, and CA The AC-OS film may be a multilayer film having two or more types.

[0166] The method for forming the oxide semiconductor film 208 and the oxide semiconductor film 209 is described below. On the gate insulating film 207, an acid that will form the oxide semiconductor film 208 and oxide semiconductor film 209 is applied. An oxide semiconductor film is formed. Next, a resin is applied to the oxide semiconductor film by a photolithography process. After forming the resist mask, a portion of the oxide semiconductor film is etched using the resist mask. By doing so, oxide semiconductor films 208 and 209 can be formed.

[0167] Oxide semiconductor films are produced by sputtering, coating, pulsed laser deposition, and laser abrasion. It can be formed using methods such as the oxidizing method and the CVD method. When forming a semiconductor film, the power supply for generating plasma is an RF power supply, A A C power supply, a DC power supply, etc., can be used as appropriate.

[0168] Sputtering gases include a noble gas (typically argon) atmosphere, an oxygen atmosphere, and a noble gas and Use an appropriate mixture of oxygen gases. In the case of a mixture of noble gases and oxygen, use the appropriate amount for the noble gas. It is preferable to increase the oxygen gas ratio.

[0169] Furthermore, the sputtering target is appropriately selected according to the composition of the oxide semiconductor film to be formed. You just need to choose.

[0170] To obtain an oxide semiconductor film that is of high purity intrinsic or substantially high purity intrinsic, a chamber In addition to evacuating the inside to a high vacuum, it is also necessary to purify the sputtering gas. The oxygen gas or argon gas used has a dew point of -40°C or lower, preferably -80°C or lower. A gas that has been purified to a temperature of -100°C or lower, more preferably -120°C or lower. By using this method, it is possible to prevent moisture and other substances from being incorporated into the oxide semiconductor film as much as possible. .

[0171] Here, as an oxide semiconductor film, we have In-G with an atomic ratio of In:Ga:Zn = 1:1:1. A 35nm thick InGa layer was created using a sputtering method with an α-Zn oxide target. - A Zn oxide film is formed. Next, a resist mask is formed on the oxide semiconductor film, and the acid By selectively etching a portion of the oxide semiconductor film, the oxide semiconductor film 208 and the oxide semiconductor film are removed. A monosemiconductor film 209 can be formed.

[0172] After this, a first heat treatment may be performed. The first heat treatment will cause the oxide semiconductor film 2 Hydrogen, water, etc. contained in 08 and the oxide semiconductor film 209 are removed, and the oxide semiconductor film 20 The hydrogen and water concentrations contained in 8 and the oxide semiconductor film 209 can be reduced. The temperature of the heat treatment is typically 300°C to 400°C, preferably 320°C or higher. The temperature should be 370°C or lower.

[0173] The first heat treatment can be carried out using an electric furnace, RTA device, etc. This allows for heat treatment at a temperature above the strain point of the substrate, albeit for a short period of time. Therefore, the heat treatment time can be shortened.

[0174] The first heat treatment involves nitrogen, oxygen, and ultra-dry air (with a water content of 20 ppm or less, preferably). Air (1 ppm or less, preferably 10 ppb or less), or noble gas (argon, helium) The procedure should be carried out under the following atmospheres: nitrogen, oxygen, ultra-dry air, or noble gases with hydrogen. It is preferable that it does not contain water, etc. Also, after heat treatment in a nitrogen or noble gas atmosphere, It may be heated in an oxygen or ultra-dry air atmosphere. As a result, the oxide semiconductor film 208 and Hydrogen, water, etc. contained in the oxide semiconductor film 209 are removed, and the oxide semiconductor film 20 8 and oxygen can be supplied into the oxide semiconductor film 209. As a result, the oxide semiconductor The amount of oxygen deficiency contained in the body membrane 208 and the oxide semiconductor film 209 can be reduced. .

[0175] Furthermore, an example is shown in which an oxide semiconductor film 209 is deposited as one of the electrodes of the capacitive element 232. However, the embodiments of the present invention are not limited thereto. In some cases, or in some circumstances, Depending on the circumstances, a non-transparent conductive film may be used as one of the electrodes of the capacitive element 232. Alternatively, the oxide semiconductor film 208 may be a film formed during a different process. Alternatively, it may be provided in a location that does not come into contact with the upper surface of the gate insulating film 207.

[0176] [Forms source electrode and drain electrode] Next, the source electrode 209a, the drain electrode 209b, and the electrode 210 are formed. , insulating film 205, oxide semiconductor film 208, and conductive film 220 on oxide semiconductor film 209 It forms (see Figure 4(C)).

[0177] The conductive film 220 can be made of aluminum, titanium, chromium, nickel, copper, yttrium, A single elemental metal consisting of zirconium, molybdenum, silver, tantalum, or tungsten, This can be used in a single-layer or multi-layer structure for an alloy with this as its main component. For example, A single-layer structure of an aluminum film containing ricon, and a double-layer structure in which an aluminum film is laminated on a titanium film. Construction: A two-layer structure in which an aluminum film is laminated on a tungsten film, copper-magnesium-aluminum A two-layer structure in which a copper film is laminated on a nium alloy film, a two-layer structure in which a copper film is laminated on a titanium film, tan A two-layer structure in which a copper film is laminated on a gusten film, a titanium film or titanium nitride film, and the titanium film Alternatively, an aluminum film or copper film can be layered on top of a titanium nitride film, and then a titanium film can be added on top of that. A three-layer structure forming a film or titanium nitride film, a molybdenum film or molybdenum nitride film, An aluminum film or copper film is laminated on top of the molybdenum film or molybdenum nitride film. Furthermore, a three-layer structure is formed by forming a molybdenum film or molybdenum nitride film on top of it, tungsten One example is a three-layer structure in which a copper film is laminated on top of a tungsten film, and then a tungsten film is formed on top of that.

[0178] Furthermore, indium tin oxide, zinc oxide, indium oxides including tungsten oxide, and acid Indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, oxide Titanium-containing indium tin oxide, indium zinc oxide, and indium with added silicon dioxide Conductive materials containing oxygen, such as um-tin oxide, and nitrogen-containing materials, such as titanium nitride and tantalum nitride. Conductive materials may be used. In addition, materials containing the aforementioned metal elements and conductive materials containing oxygen may be used. It is also possible to create a laminated structure by combining materials. Furthermore, the aforementioned materials containing metal elements, A layered structure can also be formed by combining conductive materials containing nitrogen. Furthermore, the aforementioned metals... The product of a combination of elemental materials, oxygen-containing conductive materials, and nitrogen-containing conductive materials It can also be structured in layers.

[0179] Furthermore, the thickness of the conductive film 220 is 5 nm or more and 500 nm or less, more preferably 10 nm or more. The wavelength is 300 nm or less, more preferably 10 nm to 200 nm. In this embodiment, Then, a tungsten film with a thickness of 300 nm is formed as the conductive film 220.

[0180] Next, a resist mask is formed on the conductive film 220 by a photolithography process, and the resist By selectively etching a portion of the conductive film 220 using a tomask, the source electrode 20 9a, drain electrode 209b, and electrode 210 are formed. Also, terminal electrode 116 etc. Other electrodes and wiring can also be formed at the same time.

[0181] The conductive film 220 can be etched using either a dry etching method or a wet etching method. Both may be used. Note that the etching process removes a portion of the exposed oxide semiconductor film. They may be removed (see Figure 5(A)).

[0182] [Forms an oxide insulating film] Next, an insulating film 108 is formed. The insulating film 108 is an oxide insulating film that is permeable to oxygen. Furthermore, the insulating film 108 is used when forming the insulating film 109 which will be formed later, and the oxide semiconductor film 20 It also functions as a damage mitigation membrane for 8 (see Figure 5(B)).

[0183] The insulating film 108 has a thickness of 5 nm to 150 nm, preferably 5 nm to 50 nm. Silicon oxide, silicon oxide nitride, etc. with a m or less can be used. In this context, an oxidogenic nitride film refers to a film whose composition contains more oxygen than nitrogen. A oxidized film refers to a film whose composition contains more nitrogen than oxygen.

[0184] Furthermore, the insulating film 108 preferably has a low defect content, and is typically obtained from the ESR signal. The spin density with g=2.001, which originates from silicon dangling bonds, 3 x 10 17 spins / cm 3 The following is preferable. This is because the insulating film 108 contains If the defect density is high, oxygen will bond to the defect, and oxygen in the insulating film 108 will This is because the amount of light transmitted decreases.

[0185] Furthermore, it is preferable that the number of defects at the interface between the insulating film 108 and the oxide semiconductor film 208 be small. Typically, ESR measurements show that g=1 originates from defects in the oxide semiconductor film 208. The spin density of the signal appearing at 93 is 1 × 10⁻⁶ 17 spins / cm 3 The following, and furthermore, detected It is preferable that it be below the limit.

[0186] Furthermore, in the insulating film 108, all of the oxygen that enters the insulating film 108 from the outside is absorbed by the insulating film 108. Some oxygen does not move to the outside and remains in the insulating film 108. Also, oxygen enters the insulating film 108. At the same time, the oxygen contained in the insulating film 108 moves to the outside of the insulating film 108, Oxygen movement may also occur at 10⁸.

[0187] When an oxygen-permeable oxide insulating film is formed as the insulating film 108, the insulating film 108 is provided on top of it. The oxygen that is released from the insulating film 109 is transferred to the oxide semiconductor film 208 via the insulating film 108. It can be moved.

[0188] As the insulating film 108, a silicon oxide film or a silicon oxide nitride film is preferred. i. The silicon oxide film or silicon oxide nitride film used for the insulating film 108 is, for example, a plasma The substrate placed in the vacuum-evacuated processing chamber of the CVD apparatus is subjected to a temperature between 280°C and 400°C. Maintain the pressure within the processing chamber by introducing the raw material gas into the processing chamber and adjusting the pressure between 20 Pa and 250 Pa. Furthermore, more preferably, the pressure should be 100 Pa or more and 250 Pa or less, and the electrodes provided in the processing chamber It can be formed by supplying high-frequency power.

[0189] As a raw material gas for forming a silicon oxide film or silicon oxidnitride film, silicon It is preferable to use a sedimentary gas and an oxidizing gas that contains silicon. Examples include silanes, disilanes, trisilanes, and silane fluorides. As oxidizing gases... These include oxygen, ozone, nitrous oxide, and nitrogen dioxide.

[0190] By using the above conditions, an oxide insulating film that permeates oxygen can be formed as the insulating film 108. This can be achieved. In addition, by providing the insulating film 108, oxidation in the process of forming the insulating film 109 can be prevented. It is possible to reduce damage to the semiconductor film 208.

[0191] Furthermore, by setting the substrate temperature to the above temperature under the film deposition conditions, the bonding of silicon and oxygen The resultant force becomes stronger. As a result, the insulating film 108 is permeable to oxygen, dense, and hard. Oxide insulating films, typically, are etched using 0.5 wt% hydrofluoric acid at 25°C. A silicon oxide film or acid with a grinding speed of 10 nm / min or less, preferably 8 nm / min or less. A silicon nitride film can be formed.

[0192] Furthermore, by forming the insulating film 108 while heating, an oxide semiconductor film is formed in this process. Hydrogen, water, etc., contained in 208 and the oxide semiconductor film 209 can be removed. In general, the insulating film 108 is insulated while the element formation substrate 101 is kept at a temperature of 280°C to 400°C. By forming this, hydrogen, water, etc. contained in the oxide semiconductor film 208 can be removed. The hydrogen contained in the oxide semiconductor film 208 combines with oxygen radicals generated in the plasma. And it turns into water. Because the substrate is heated during the film formation process of insulating film 108, oxygen and water Water generated by the elementary bonding desorbs from the oxide semiconductor film. That is, in the plasma CVD method. By forming the insulating film 108, the water and hydrogen content contained in the oxide semiconductor film This can be reduced.

[0193] Furthermore, since heating is performed in the process of forming the insulating film 108, the oxide semiconductor film 208 and The heating time while the oxide semiconductor film 209 is exposed is short, and the oxide semiconductor film is not affected by the heat treatment. The amount of oxygen desorbed from the conductive film can be reduced. That is, the amount of oxygen contained in the oxide semiconductor film can be reduced. This can reduce the amount of oxygen deficiency.

[0194] Furthermore, by setting the pressure in the processing chamber to between 100 Pa and 250 Pa, the insulating film 108 Because the water content is reduced, it reduces variations in the electrical characteristics of the transistor. Both methods can suppress fluctuations in the threshold voltage.

[0195] Furthermore, by setting the pressure in the processing chamber to between 100 Pa and 250 Pa, the insulating film 108 is deposited. In doing so, damage to oxide semiconductor film 208 and oxide semiconductor film 209 is reduced. This is possible, and oxygen vacancies are contained in the oxide semiconductor film 208 and oxide semiconductor film 209. The amount can be reduced. In particular, the amount of insulating film 108 or the insulating film 109 that is formed later By increasing the film temperature, typically to a temperature higher than 220°C, the oxide semiconductor film 20 Some of the oxygen contained in 8 and the oxide semiconductor film 209 is desorbed, making it easier for oxygen vacancies to form. stomach.

[0196] Furthermore, in order to improve the reliability of the transistor, the insulating film 109 that will be formed later will have a defect amount in the film. When formed using film formation conditions with low ions, the amount of oxygen desorption from the insulating film 109 is easily reduced. Then, due to the oxygen supply from the insulating film 109, the oxide semiconductor film 208 and the oxide semiconductor film are heated. It may be difficult to compensate for the oxygen deficiency in the conductive film 209. However, the processing chamber The pressure is set to 100 Pa or more and 250 Pa or less, and the oxide semiconductor during the deposition of the insulating film 108 By reducing damage to the body film 208 and the oxide semiconductor film 209, the insulating film 109 Even with a low oxygen supply, the acid in oxide semiconductor film 208 and oxide semiconductor film 209 This makes it possible to reduce prime defects.

[0197] Furthermore, by increasing the amount of oxidizing gas relative to the silicon-containing sedimentary gas to more than 100 times, It is possible to reduce the hydrogen content contained in the edge film 108. As a result, oxide semiconductor Because the amount of hydrogen mixed into film 208 and oxide semiconductor film 209 can be reduced, transistor This can suppress the negative shift in the threshold voltage.

[0198] In this embodiment, the insulating film 108 is made of plastic using silane and nitrous oxide as raw material gases. A silicon oxide nitride film with a thickness of 50 nm is formed by the Zuma CVD method. Under these conditions, It is possible to form a silicon oxidoxide-nitride film that allows oxygen to permeate.

[0199] Next, insulating film 109 is formed in contact with insulating film 108. Insulating film 109 has a stoichiometric composition It is formed using an oxide insulating film containing more oxygen than satisfies the requirement. In oxide insulating films that contain more oxygen than they can accommodate, some of the oxygen is removed when heated. Oxide insulating films containing more oxygen than satisfying the stoichiometric composition are, according to TDS analysis, The amount of oxygen removed, when converted to oxygen atoms, is 1.0 × 10⁻⁶. 18 atoms / cm 3 The above is favorable. 3.0 x 10 20 atoms / cm3 The above describes the oxide insulating film. The substrate temperature during DS analysis should be between 100°C and 700°C, or between 100°C and 5°C. A temperature range of 00°C or lower is preferred.

[0200] Furthermore, after forming the insulating film 108, the insulating film 109 is formed continuously without exposure to the atmosphere. It is preferable to do so. After forming the insulating film 108, do not open it to the atmosphere, and control the flow rate and pressure of the raw material gas. By adjusting the high-frequency power and substrate temperature to one or more units, the insulating film 109 is formed continuously. To reduce the concentration of impurities originating from atmospheric components at the interface between insulating film 108 and insulating film 109. In addition, the oxygen contained in the insulating film 109 is transferred to the oxide semiconductor film 208 and the oxide semiconductor film. It is possible to move it to the body membrane 209, and the oxide semiconductor film 208 and oxide semiconductor film This can reduce the oxygen deficit by 209.

[0201] Furthermore, it is preferable that the insulating film 109 has a low defect count, and typically, by ESR measurement... The spin density of the signal appearing at g=2.001, which originates from silicon dangling bonds, 1.5 × 10 18 spins / cm 3 Less than, and even 1 x 10 18 spins / cm 3 below It is preferable that the insulating film 109 is an oxide semiconductor film compared to the insulating film 108. Because it is far from 208, it can have a higher defect density than insulating film 108.

[0202] As the insulating film 109, a silicon oxide film or a silicon oxide nitride film is preferred. i. The silicon oxide film or silicon oxide nitride film used for the insulating film 109 is, for example, plasm The substrate placed in the vacuum-evacuated processing chamber of the CVD apparatus is subjected to temperatures between 180°C and 280°C. More preferably, the temperature is maintained between 200°C and 240°C, and the raw material gas is introduced into the processing chamber for processing. The pressure inside the room should be between 100 Pa and 250 Pa, more preferably between 100 Pa and 2 The pressure should be 0.00 Pa or less, and 0.17 W / cm² should be applied to the electrode installed in the processing chamber. 2 More than 0.5W / cm 2 More preferably, 0.25 W / cm² 2 More than 0.35W / cm 2 The following high-frequency power It can be formed by the conditions under which it is supplied.

[0203] The thickness of the insulating film 109 is 30 nm or more and 500 nm or less, preferably 50 nm or more and 400 nm or less. It can be less than or equal to m.

[0204] As the film deposition conditions for the insulating film 109, a high-frequency power of the above power density in a reaction chamber at the above pressure By supplying this, the decomposition efficiency of the raw material gas in the plasma is increased, and oxygen radicals increase. As the oxidation of the source gas progresses, the oxygen content in the insulating film 109 becomes higher than the stoichiometric ratio. On the other hand, in films formed at the above temperature, the bonding force between silicon and oxygen is weak. Therefore, some of the oxygen in the film is removed by the subsequent heat treatment. As a result, stoichiometric compounds An oxide insulating film containing more oxygen than the required amount, with some of the oxygen being removed upon heating. It is possible to form an insulating film 108 on the oxide semiconductor film 208. Therefore, in the process of forming the insulating film 109, the insulating film 108 becomes the oxide semiconductor film 208 This acts as a protective film. As a result, damage to the oxide semiconductor film 208 is reduced, while power density is maintained. The insulating film 109 can be formed using high-frequency power.

[0205] Furthermore, in the film formation conditions for insulating film 109, the silicon-containing deposition gas relative to the oxidizing gas By increasing the flow rate, it is possible to reduce the number of defects in the insulating film 109. ESR measurement revealed that this originates from dangling bonds in silicon, appearing at g=2.001. The spin density of the signal is 6 × 10 17 spins / cm 3 Less than 3 × 10 17 s pins / cm 3 The following is preferably 1.5 × 10 17 spins / cm 3 The following defects This allows for the formation of a small amount of oxide insulating film. As a result, the reliability of the transistor is improved. It is possible.

[0206] In this embodiment, the insulating film 109 is a plastic made using silane and nitrous oxide as raw material gases. A silicon oxide nitride film with a thickness of 400 nm is formed using the Zuma CVD method.

[0207] Next, a second heat treatment is performed. The temperature of this heat treatment is typically between 150°C and 400°C. The following is preferably 300°C to 400°C, preferably 320°C to 370°C. ru.

[0208] The second heat treatment can be carried out using an electric furnace, RTA device, etc. Therefore, heat treatment can be performed at a temperature above the strain point of the substrate for a short period of time. The heat treatment time can be shortened.

[0209] The second heat treatment involves nitrogen, oxygen, and ultra-dry air (with a water content of 20 ppm or less, preferably). Air (1 ppm or less, preferably 10 ppb or less), or noble gas (argon, helium) The procedure should be carried out under the following atmospheres: nitrogen, oxygen, ultra-dry air, or noble gases with hydrogen. Preferably, it does not contain water or other substances.

[0210] The second heat treatment transfers some of the oxygen contained in the insulating film 109 to the oxide semiconductor film 208. This allows for movement and the replenishment of oxygen vacancies contained in the oxide semiconductor film 208. As a result, the amount of oxygen vacancies in the oxide semiconductor film 208 can be further reduced.

[0211] Furthermore, if the insulating film 108 and insulating film 109 contain water, hydrogen, etc., the water, hydrogen, etc. can be blocked. An insulating film 110 having a coating function is subsequently formed and heat treatment is performed, resulting in the insulating film 108 and Water, hydrogen, etc. contained in the insulating film 109 move to the oxide semiconductor film 208, and the oxide semiconductor film A defect occurs in 208. However, due to the heating, the insulating film 108 and the insulating film It is possible to desorb water, hydrogen, etc. contained in 10⁹, and the electrical characteristics of the transistor This reduces variability and suppresses fluctuations in the threshold voltage.

[0212] Furthermore, by forming the insulating film 109 on the insulating film 108 while heating, an oxide semiconductor film is formed. It is possible to transfer oxygen to 208 and fill in the oxygen vacancies contained in the oxide semiconductor film 208. Since this is possible, a second heat treatment is not necessary.

[0213] Here, the material is heated at 350°C for 1 hour in a mixed gas atmosphere of nitrogen and oxygen.

[0214] Furthermore, when forming the pair of source electrodes 209a and drain electrodes 209b, the conductive film 220 Etching damages the oxide semiconductor film 208, and the oxide semiconductor film 208 Back channel (in the oxide semiconductor film 208, opposite the surface facing the gate electrode 206) Oxygen deficiencies occur on the side surface. However, oxygen that satisfies the stoichiometric composition in the insulating film 109 By applying an oxide insulating film containing more oxygen, the backchar can be removed by heat treatment. This allows for the repair of oxygen vacancies on the Nell side. This enables the oxide semiconductor film 208 to Because the number of defects can be reduced, the reliability of the transistor can be improved. Cut.

[0215] [Remove a portion of the oxide insulating film] Next, a mask is formed on the insulating film 109 by a photolithography process, and the insulating film 109, And selective etching of a portion of the insulating film 108 to create openings on the oxide semiconductor film 209 Form 122. At this time, other openings not shown are also formed simultaneously (see Figure 5(C)). Etching of insulating film 109 and insulating film 108 is performed by dry etching, wet etching. Etching methods, or etching methods combining both, can be used.

[0216] A second heat treatment may be performed after this. The second heat treatment will cause the insulating film 109 to contain A portion of the oxygen is transferred to the oxide semiconductor film 208 and the oxide semiconductor film 209, and the oxide It is possible to reduce oxygen vacancies contained in the semiconductor film 208 and the oxide semiconductor film 209. That is the case.

[0217] [Forms a protective film] Next, an insulating film 110 is formed (see Figure 6(A)). Oxygen and hydrogen are used as the insulating film 110. By using an insulating film that has a blocking effect, such as water, alkali metals, or alkaline earth metals... As a result, oxygen contained in the oxide semiconductor film 208, insulating film 108, and insulating film 109 is exposed to the outside This prevents the diffusion of hydrogen into the oxide semiconductor film 208 from the outside. It can prevent the intrusion of impurities such as water. Examples of such insulating films include silicon nitride films, silicon nitride oxide films, and aluminum nitride films. Aluminum nitride film, aluminum oxide film, aluminum oxide nitride film, galium oxide gallium oxide film, gallium oxide film, yttrium oxide film, yttrium oxide film, hafni oxide film Examples include nitride insulating films such as um film and hafnium oxide-nitride, as well as oxide insulating films.

[0218] The configuration of the insulating film 110 is not limited to the above configuration, and can also be an oxide insulating film or a nitride insulating film. It can be a single layer or a multi-layered structure.

[0219] In this embodiment, a silicon nitride film containing hydrogen is formed as the insulating film 110.

[0220] Furthermore, the oxide semiconductor film 209 is in contact with the insulating film 110 at the opening 122. Then, Hydrogen contained in the insulating film 110 diffuses into the oxide semiconductor film 209 at the opening 122. Electrons, which act as carriers, are generated by combining with oxygen in the oxide semiconductor film 209. Furthermore, when the insulating film 110 is deposited by plasma CVD or sputtering, the opening 1 In step 22, the oxide semiconductor film 209 is exposed to plasma, and oxygen depletion occurs in the oxide semiconductor film 209. Loss is generated. When hydrogen contained in the insulating film 110 enters the oxygen vacancy, the carrier A certain electron is generated. As a result, the conductivity of the oxide semiconductor film 209 increases, and conductivity The oxide semiconductor film 209 has conductivity. That is, the conductive oxide semiconductor film 209 is It can also be described as a highly conductive oxide semiconductor film. It can also be described as a highly conductive metal oxide film.

[0221] Furthermore, before forming the insulating film 110, the oxide semiconductor film 209 was treated with a plasma containing a rare gas and hydrogen. By exposing it to the light, oxygen vacancies are formed in the oxide semiconductor film 209, and the oxide semiconductor film Hydrogen can be added to 209. As a result, in the oxide semiconductor film 209, It is possible to further increase the electron carriers, and the oxide semiconductor film has conductivity. The conductivity of 209 can be further enhanced.

[0222] The conductive oxide semiconductor film 209 has the same metallic elements as the oxide semiconductor film 208. It is a film that is characterized by containing impurities. Among the impurities is hydrogen. In addition to hydrogen, other impurities include boron, phosphorus, tin, antimony, noble gas elements, and aluminum. Potassium metals, alkaline earth metals, etc. may be included.

[0223] Both the oxide semiconductor film 208 and the conductive oxide semiconductor film 209 are gate insulating. Although formed on film 207, the concentration of impurities contained differs. Specifically, oxide semiconductor film The impurity concentration of the conductive oxide semiconductor film 209 is higher than that of 208. For example, oxidation The hydrogen concentration contained in the semiconductor film 208 is 5 × 10⁻⁶. 19 atoms / cm 3 Less than, preferred kuha 5×10 18 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 The following is more preferable: 5 x 10 17 atoms / cm 3 More preferably 1 × 10 16 atoms / cm 3The following is the water contained in the conductive oxide semiconductor film 209 The elementary concentration is 8 × 10 19 Preferably 1 × 10 20 atoms / cm 3 The above is a better option. Mashikuha 5 x 10 20 That concludes the explanation. Furthermore, compared to the oxide semiconductor film 208, it has conductivity. The hydrogen concentration in the oxide semiconductor film 209 is twice, preferably 10 times or more.

[0224] Furthermore, the conductive oxide semiconductor film 209 has a lower resistivity than the oxide semiconductor film 208. The resistivity of the oxide semiconductor film 208 is equal to the resistivity of the conductive oxide semiconductor film 209. 1 x 10 1 more than 1x10 8 It is preferable that it be less than twice the value. Conductive oxide semiconductor The resistivity of film 209 is typically 1 × 10⁻⁶. -3 Ωcm or more, 1 × 10 4 Less than Ωcm, and Preferably, the resistivity is 1 × 10⁻⁶. -3 Ωcm or more, 1 × 10 -1 It should be less than Ωcm.

[0225] However, one embodiment of the present invention is not limited thereto, and includes a conductive oxide semiconductor film In some cases, 209 may not be in contact with the insulating film 110.

[0226] Furthermore, one embodiment of the present invention is not limited thereto, and includes a conductive oxide semiconductor film 209 may be formed in a separate process from the oxide semiconductor film 208. In that case, the conductivity is The oxide semiconductor film 209 may have a different material composition than the oxide semiconductor film 208. For example, the conductive oxide semiconductor film 209 is made of indium tin oxide, tung oxide Indium oxide containing tungsten, indium zinc oxide containing tungsten oxide, and tungsten oxide. Indium oxide containing tan, indium tin oxide containing titanium oxide, indium tin oxide Formed using materials such as indium zinc oxide and indium tin oxide containing silicon oxide. That's good too.

[0227] The display device shown in this embodiment has a semiconductor film of a transistor and simultaneously one of the capacitive elements. An electrode is formed. In addition, a light-transmitting conductive film that functions as a pixel electrode is formed on the capacitive element. It is used as an electrode. Therefore, in order to form a capacitive element, a new conductive film is formed. This eliminates the need for intermediate steps and reduces the manufacturing process for semiconductor devices. Also, the pair that make up the capacitive element Because the electrodes are translucent, the capacitive element is also translucent. As a result, the occupied area of ​​the capacitive element This allows for increasing the size while also increasing the aperture ratio of the pixels.

[0228] Next, selective etching of portions of insulating film 110, insulating film 109, and insulating film 108. Then, opening 142 is formed. At this time, other openings not shown are also formed simultaneously. For openings 142 etc., a resist mask is formed by a photolithography process, and the resist It can be formed by etching the area not covered by the mask (Figure 6(B) (See reference.) The surface of the source electrode 209a is exposed at the bottom of the opening 142.

[0229] Note that etching of insulating film 110, insulating film 109, and insulating film 108 is performed, for example, by dry etching. The etching method can be used. However, it is not limited to this, and the wet etching method, A method combining dry etching and wet etching may also be used.

[0230] [Forms a conductive film] Next, a conductive film for forming the conductive film 145 is applied to the insulating film 110, covering the opening 122. Form. A resist mask is formed on the conductive layer by a photolithography process, and the resist The areas not covered by the mask are etched to form the conductive film 145 (Figure 7(A)). reference.).

[0231] Furthermore, simultaneously with the formation of the conductive film 145, the gate electrode 206 and the oxide semiconductor film 208 are superimposed. An electrode 226 can be formed in the region. The conductive film 145 and the electrode 226 are gate It can be formed using the same materials and methods as electrode 206.

[0232] Furthermore, by forming the conductive film 145 with a light-transmitting conductive material, the capacitive element 232 , it can be made into a light-transmitting capacitive element. In this embodiment, the conductive film 145 and An indium tin oxide with a thickness of 100 nm is used as electrode 226 (see Figure 7(A)). .

[0233] Furthermore, electrode 226 can function as a gate electrode. When either 6 or electrode 226 is simply called the "gate electrode," the other is called the "back electrode." It is sometimes referred to as a "gate electrode." Also, either gate electrode 206 or electrode 226 Sometimes one is called the "first gate electrode" and the other the "second gate electrode."

[0234] Generally, the back gate electrode is formed of a conductive film, and the gate electrode and back gate electrode form a semiconductor. It is positioned so as to sandwich the channel formation region of the layer. Therefore, the back gate electrode is the gate electrode It can function similarly to a pole. The potential of the buck gate electrode is the same potential as the gate electrode. It may be done, and it may be set to GND potential or any other potential. The potential of the back gate electrode is changed. By doing so, the threshold voltage of the transistor can be changed.

[0235] Furthermore, since the gate electrode and back gate electrode are formed of a conductive film, outside the transistor... Function to prevent the generated electric field from acting on the semiconductor layer in which the channel is formed (especially static electricity) It also has an electrostatic shielding function.

[0236] Furthermore, when light is incident from the back gate electrode side, the back gate electrode has light-shielding properties. By forming it with a conductive film, it prevents light from entering the semiconductor layer from the back gate electrode side. This prevents photodegradation of the semiconductor layer and shifts the threshold voltage of the transistor. This prevents deterioration of electrical properties, such as those mentioned above.

[0237] By providing the gate electrode 206 and electrode 226 with the oxide semiconductor film 208 in between, By setting the gate electrode 206 and electrode 226 to the same potential, the oxide semiconductor film 208 As the region through which carriers flow becomes larger in the direction of film thickness, the amount of carrier movement It increases. As a result, the on-current of the transistor increases, and the field-effect mobility also increases. It will get worse.

[0238] Furthermore, the gate electrode 206 and electrode 226 each have the function of shielding against an external electric field. Because of this, the charge present in the layer below the gate electrode 206 and above the electrode 226 is This does not affect the oxide semiconductor film 208. As a result, stress testing (for example, negative current applied to the gate) is not performed. Applying pressure - GBT (Gate Bias-Temperature) stress test and The change in threshold voltage before and after applying a positive voltage to the gate (GBT stress test). The dynamics are small. Furthermore, it suppresses fluctuations in the on-current rise voltage at different drain voltages. This can be achieved when the gate electrode 206 and electrode 226 are at the same potential. Even if they exist, they can still occur even if they are at different potentials.

[0239] Note that the BT stress test is a type of accelerated stress test, and it tests the transient effects that occur due to long-term use. The characteristic changes of the st (i.e., changes over time) can be evaluated in a short time. In particular, BT st The amount of variation in the transistor's threshold voltage before and after the test is a crucial factor in determining reliability. This is an important indicator. The smaller the fluctuation in threshold voltage before and after the BT stress test, the better. It can be said that this is a highly reliable transistor.

[0240] Furthermore, it has a gate electrode 206 and an electrode 226, and the gate electrode 206 and electrode 22 By setting 6 to the same potential, the amount of fluctuation in the threshold voltage is reduced. Therefore, multiple transistors The variation in electrical characteristics in the zista is also reduced at the same time.

[0241] [Forms a planar film] Next, an insulating film 211 is formed on the conductive film 145. The insulating film 211 is similar to the insulating film 205. It can be formed using the following materials and methods.

[0242] Furthermore, in order to reduce surface irregularities on the surface of the light-emitting element 125, a planarization treatment is applied to the insulating film 211. You may perform a planarization treatment. There are no particular limitations on the planarization treatment, but polishing treatment (e.g., chemical machine polishing) is also acceptable. Polishing method (Chemical Mechanical Polishing: CMP), This can be done by dry etching.

[0243] Furthermore, by forming the insulating film 211 using an insulating material having a planarization function, the polishing process is eliminated. This can also be omitted. Examples of insulating materials with planarization properties include polyimide resin. Organic materials such as acrylic resin can be used. In addition to the above organic materials, low dielectric constant materials can also be used. Materials (low-k materials), etc., can be used. Furthermore, insulating films formed from these materials can be used. Multiple layers may be stacked to form an insulating film 211.

[0244] Furthermore, a portion of the insulating film 211 in the region overlapping with the opening 142 is removed to form the opening 143. This is done. At this time, other openings not shown are also formed simultaneously. Later, the external electrode 124 The insulating film 211 in the connecting region is also removed. Note that openings 143, etc., are made on the insulating film 211. A resist mask is formed by the photolithography process, and the resist mask of the insulating film 211 is formed. It can be formed by etching the area not covered by the coating (see Figure 7(B)). By forming section 143, the surface of the source electrode 209a is exposed.

[0245] Furthermore, by using a photosensitive material for the insulating film 211, a resist mask can be used. An opening 143 can be formed without any problems. In this embodiment, a photosensitive polyimide resin The insulating film 211 and the opening 143 are formed using this method.

[0246] [Forms the anode] Next, an electrode 115 is formed on the insulating film 211 (see Figure 8(A)). The electrode 115 is then The EL layer 117 formed therein is formed using a conductive material that efficiently reflects the light it emits. This is preferable. Note that the electrode 115 is not limited to a single layer, but may also have a multi-layered structure. For example... If electrode 115 is used as the anode, the layer in contact with the EL layer 117 is made of indium tin oxide. A layer with a higher work function and light transmittance than the EL layer 117 of an object is used, and a layer in contact with this layer is used. A layer with high emissivity (such as aluminum, an aluminum-containing alloy, or silver) may be provided. .

[0247] In this embodiment, a display device with a top emission structure is given as an example, but Mu-emission structure (bottom injection structure), or dual-emission structure (double-sided injection structure) It can also be used as a display device.

[0248] The display device has a bottom emission structure (bottom surface injection structure) and a dual emission structure. When using a display device with a double-sided injection structure, a light-transmitting conductive material is used for the electrode 115. Just be there.

[0249] Electrode 115 is formed by creating a conductive film on the insulating film 211, and photolithography A resist mask is formed by the process, and the area of ​​the conductive film not covered by the resist mask It can be formed by etching the region. The etching of the conductive film is performed by dry etching. Wet etching or a combination of both methods can be used.

[0250] [To form a partition] Next, a partition wall 114 is formed. The partition wall 114 prevents adjacent light-emitting elements 125 from unintentionally becoming electrically charged. It is provided to prevent short circuits and false light emission. Also, it is used in the formation of the EL layer 117, which will be described later. When using a metal mask, it also has the function of preventing the metal mask from coming into contact with the electrode 115. The partition wall 114 is made of organic resin materials such as epoxy resin, acrylic resin, and imide resin, and acid It can be formed from inorganic materials such as silicon dioxide. The partition wall 114 has tapered side walls. Alternatively, it is preferable to form it so that it becomes an inclined surface with a continuous curvature. By giving the side walls of wall 114 this shape, the EL layer 117 and electrodes 11 that are formed later can be made The covering properties of 8 can be improved.

[0251] [Forms an EL layer] The configuration of the EL layer 117 will be described in Embodiment 7.

[0252] [Forms a cathode] In this embodiment, electrode 118 is used as the cathode, so electrode 118 is connected to the EL layer 11 described later. It is preferable to form it using a material with a small work function that can inject electrons into 7. Rather than elemental metals with small work functions, alkali metals or alkaline earth elements with small work functions. A layer of metal with a few nanometers of structure is formed as a buffer layer, and a metal material such as aluminum is placed on top of it. Formed using conductive oxide materials such as indium tin oxide, or semiconductor materials. Alternatively, an alkaline earth metal oxide, halide, or magnesium may be used as a buffer layer. Alloys such as nesium-silver can also be used.

[0253] Furthermore, when extracting light emitted from the EL layer 117 via the electrode 118, the electrode 118 Preferably, it has light transmittance to visible light. Electrode 115, EL layer 117, electrode 118 This forms the light-emitting element 125.

[0254] [Forming the opposing substrate] A light-shielding film 264, a colored layer 266, and an overcoat layer 268 are formed on the substrate 121 ( Hereinafter, this will also simply be referred to as "substrate 121.") is formed on the electrode 118 via the adhesive layer 120. (See Figure 9.) The configuration of the circuit board 121 will be explained later.

[0255] The adhesive layer 120 is formed in contact with the electrode 118. The substrate 121 is bonded by the adhesive layer 120. It is fixed in place. The adhesive layer 120 can be a light-curing adhesive, a reaction-curing adhesive, or a thermo-curing adhesive. Molded adhesives or anaerobic adhesives can be used. For example, epoxy resin, acrylic Resins, imide resins, etc. can be used. In the case of a top emission structure, adhesive layer 12 0 contains desiccants smaller than the wavelength of light (such as zeolites) or fillers with a high refractive index (oxidizing When titanium or zirconium is mixed in, the light extraction efficiency of the EL layer 117 improves. It is suitable for raising.

[0256] [Remove the element-forming substrate] Next, the element forming substrate 101, which is in contact with the insulating film 205 via the release layer 113, is placed in the insulating film 205 It is peeled off (see Figure 10). The peeling method involves applying mechanical force (human hand). Using methods such as peeling with jigs, separating while rotating rollers, or using ultrasound This can be done by cutting into the peeling layer 113 with a sharp blade or laser beam irradiation. Insert and pour water into the cut. Alternatively, spray a mist of water into the cut. Due to capillary action, water seeps between the peeling layer 113 and the base layer 119, forming the element base The plate 101 can be easily peeled off.

[0257] [Bonding the circuit boards together] Next, the substrate 111 is bonded to the insulating film 205 via the adhesive layer 112 (see Figure 11). In this way, the display device 100 can be manufactured. The adhesive layer 112 is made of adhesive layer 1 The same materials as in 20 can be used.

[0258] In this way, the display device 100 can be manufactured.

[0259] The display device 100 shown in this embodiment includes transistors 431 and 233 and In the non-overlapping regions, a portion of insulating film 108 and insulating film 109 is removed. By removing the edge film 108 and the insulating film 109, the display device 100 becomes more flexible. This makes it possible to achieve a highly flexible display device. According to one aspect of the invention, the material becomes less prone to breakage even when bending is repeated. This makes it possible to realize a highly reliable display device.

[0260] [Configuration of opposing substrates] Next, regarding the structure formed on the substrate 121 which is provided opposite the substrate 111, the following explanation will be given. To perform the task.

[0261] First, prepare the substrate 121. The same material as substrate 111 will be used for substrate 121. This can be done. Next, a light-shielding film 264 is formed on the substrate 121 (see Figure 12(A)). Next, a colored layer 266 is formed (see Figure 12(B)).

[0262] The light-shielding film 264 and the colored layer 266 are produced using various materials by printing, inkjet, and The desired positions are formed using photolithography.

[0263] Next, an overcoat layer 268 is formed on the light-shielding film 264 and the colored layer 266 (Figure 12). (See (C)).

[0264] The overcoat layer 268 can be, for example, acrylic resin, epoxy resin, polyimide, etc. An organic insulating film can be used. For example, by forming an overcoat layer 268, For example, it suppresses the diffusion of impurities contained in the colored layer 266 towards the light-emitting element 125. It is possible. However, the overcoat layer 268 is not necessarily required. - A structure that does not form a coat layer 268 is also possible.

[0265] The structure to be formed on the substrate 121 can be created through the above process.

[0266] [Regarding film formation methods] Various films disclosed in this embodiment, such as metal films, semiconductor films, and inorganic insulating films, can be produced by sputtering or It can be formed by plasma CVD, but other methods, such as thermal CVD (Che It may also be formed by the (mical Vapor Deposition) method. Thermal CVD method As an example, MOCVD (Metal Organic Chemical Vapor Deposition method and ALD (Atomic Layer Deposition) You may use the ) method.

[0267] Thermal CVD is a film deposition method that does not use plasma, so defects are generated by plasma damage. It has the advantage of not being affected.

[0268] In the thermal CVD method, the raw material gas and oxidizer are simultaneously introduced into the chamber, and the chamber pressure is reduced to atmospheric pressure. Alternatively, the film is formed by reacting the material near or on the substrate under reduced pressure, causing it to deposit on the substrate. That's fine.

[0269] Furthermore, the ALD method involves maintaining atmospheric pressure or reduced pressure inside the chamber, and sequentially supplying the raw material gases for the reaction. The gas can then be introduced into the chamber, and the film deposition process may be carried out by repeating this gas introduction sequence. For example, by switching between each switching valve (also called a high-speed valve), you can create two or more types. The raw material gases are supplied to the chamber in order, and the first raw material gas is supplied in order to prevent the mixing of multiple types of raw material gases. An inert gas (such as argon or nitrogen) is introduced simultaneously with or after the refrigerant gas, Introducing the raw material gas (2). Note that if an inert gas is introduced simultaneously, the inert gas should be... It becomes a carrier gas, and when introducing the second raw material gas, an inert gas may also be introduced at the same time. Also, instead of introducing an inert gas, the first raw material gas is discharged by vacuum evacuation. A second raw material gas may be introduced. The first raw material gas is adsorbed onto the surface of the substrate to form the first layer. The film is formed and reacts with a second raw material gas introduced later, so that the second layer is laminated on top of the first layer. A thin film is formed. This process is repeated multiple times while controlling the gas introduction sequence until the desired thickness is reached. By doing so, a thin film with excellent step coverage can be formed. The thickness of the thin film is determined by the order of gas introduction. Because it can be adjusted by the number of times the process is repeated, precise film thickness adjustment is possible. It is suitable for fabricating thin FETs.

[0270] Thermal CVD methods such as MOCVD and ALD are used for the metal film and semiconductor film disclosed in this embodiment. It can form various films, such as inorganic insulating films, for example, an In-Ga-Zn-O film. When forming a film, trimethylindium, trimethylgallium, and dimethylzinc are used. The chemical formula for trimethylindium is In(CH3)3. The chemical formula for gallium is Ga(CH3)3. The chemical formula for dimethylzinc is Zn. It is (CH3)2. Furthermore, it is not limited to these combinations, and trimethylgallium can be substituted. Triethylgallium (chemical formula Ga(C2H5)3) can also be used, and dimethyl sulfate Diethylzinc (chemical formula Zn(C2H5)2) can also be used as a substitute for lead.

[0271] For example, when forming a hafnium oxide film using a film deposition apparatus that utilizes ALD, the solvent and A liquid containing a hafnium precursor compound (hafnium alkoxide solution, typically tetrak The raw material gas is vaporized dimethylamide hafnium (TDMAH), and the oxidizing agent is O Two types of gases, O3, are used. Furthermore, the chemical reaction of tetrakisdimethylamidehafnium... The chemical formula is Hf[N(CH3)2]4. Other material liquids include tetrakis(eth Examples include methylamide (hafnium).

[0272] For example, when forming an aluminum oxide film using a film deposition apparatus that utilizes ALD, the solvent And a liquid containing an aluminum precursor compound (such as trimethylaluminum (TMA)) Two types of gases are used: a converted raw material gas and H2O as an oxidizing agent. The chemical formula for luminium is Al(CH3)3. Other materials include Tris(Di Methylamide) Aluminum, Triisobutylaluminum, Aluminum Tris(2, Examples include 2,6,6-tetramethyl-3,5-heptanedione).

[0273] For example, when forming a silicon oxide film using a film deposition apparatus that utilizes ALD, hexa Rolodisilane is adsorbed onto the film-forming surface, and chlorine contained in the adsorbed material is removed, causing an oxidizing gas (O2) A radical (nitrous oxide) is supplied and reacted with the adsorbed material.

[0274] For example, when depositing a tungsten film using a film deposition apparatus that utilizes ALD, WF6 gas The initial tungsten film is formed by sequentially introducing S and B2H6 gas, and then WF6 A tungsten film is formed by simultaneously introducing gas and H2 gas. Note that B2H6 gas can be used instead. SiH4 gas may also be used.

[0275] For example, oxide semiconductor films, such as In-Ga-Zn-O, can be deposited using an ALD (Advanced Laser Deposition) system. When forming a film, In(CH3)3 gas and O3 gas are introduced sequentially and repeatedly. An O layer is formed, and then Ga(CH3)3 gas and O3 gas are introduced simultaneously to form a GaO layer. After that, Zn(CH3)2 gas and O3 gas are simultaneously introduced to form a ZnO layer. Note that the order of these layers is not limited to this example. Also, by mixing these gases, In-Ga A mixed compound layer such as an -O layer, an In-Zn-O layer, or a Ga-Zn-O layer may be formed. Oh, instead of O3 gas, we can use H2O gas obtained by bubbling with an inert gas such as Ar. While this is also acceptable, it is preferable to use O3 gas that does not contain H. Alternatively, In(C2H5)3 gas may be used. Also, instead of Ga(CH3)3 gas... Alternatively, Ga(C2H5)3 gas may be used. In addition, instead of In(CH3)3 gas, (C2H5)3 gas may be used. Alternatively, Zn(CH3)2 gas may be used.

[0276] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0277] (Embodiment 2) The configuration of the top-emission display device 100 is modified to create a bottom-emission structure. A display device 150 can be manufactured.

[0278] Figure 13 shows an example of the cross-sectional configuration of the display device 150 with a bottom emission structure. This refers to the area shown by the dashed line A1-A2 in Figure 1(A), which is a perspective view of the display device 100, This is a cross-sectional view of the same area. The display device 150 with a bottom emission structure has a light-shielding film 264 The formation positions of the colored layer 266 and the overcoat layer 268 are different from those of the display device 100. .

[0279] In the display device 150, a light-shielding film 264, a colored layer 266, and an overcoat layer 26 8 is formed on the substrate 111.

[0280] Furthermore, the bottom emission structure of the display device 150 has electrodes 115 made of light-transmitting conductive material. Formed using a conductive material, the electrode 118 efficiently reflects the light emitted by the EL layer 117. It is formed using electrolytic materials.

[0281] The display device 150 transmits light 235 emitted from the EL layer 117 to the substrate via the colored layer 266. It can be ejected from side 111.

[0282] Furthermore, as shown in Figure 23, similar to Figure 21, a touch sensor can be provided on the substrate 111. It is possible. Also, as shown in Figure 24, similar to Figure 22, a touch sensor is provided on the substrate 921. It is also possible to do so.

[0283] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0284] (Embodiment 3) Furthermore, by combining the display device 100 and the display device 150, light is emitted from the EL layer 117. The light 235 is emitted from both the substrate 111 side and the substrate 121 side using a dual emitter. This makes it possible to realize a display device with a cushion structure (double-sided injection structure).

[0285] Furthermore, when forming a display device with a dual emission structure (double-sided injection structure), electrode 1 Both 15 and electrode 118 may be formed using a light-transmitting conductive material.

[0286] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0287] (Embodiment 4) In this embodiment, the configuration of the transistor 431 disclosed in the above embodiment will be described. Figure 14 shows a top view and a cross-sectional view of transistor 431 as an example of a semiconductor device. Transistor 431 is a channel-etch type transistor. Transistors 233 and 231 can also have the same structure as transistor 431. Cut.

[0288] Figure 14(A) is a top view of transistor 431. Also, Figure 14(B) is a top view of Figure 14(A). Figure 14(C) is a cross-sectional view of the area indicated by the dashed line X1-X2 in Figure 14(A). This is a cross-sectional view of the region indicated by the dashed line Y1-Y2. Figure 14(B) shows a transistor. Figure 14(C) shows a cross-section of transistor 431 in the channel length direction. This is a cross-section in the width direction.

[0289] Transistor 431 consists of a gate electrode 206, a gate insulating film 207, and a gate insulating film 20 7 is connected to the oxide semiconductor film 208 which overlaps with the gate electrode 206, and the oxide semiconductor film 208 It has a source electrode 209a and a drain electrode 209b that are in contact with the gate. 07, On the oxide semiconductor film 208, source electrode 209a, and drain electrode 209b A protective film 141 is formed, which includes insulating film 108, insulating film 109, and insulating film 110. Furthermore, the insulating film 110 has an electrode 226 that overlaps with the oxide semiconductor film 208.

[0290] The transistor 431 has multiple gate electrodes, and an oxide semiconductor film 208 is placed between these electrodes. It is a dual-gate transistor, as shown in the channel width direction in Figure 14(C). In this configuration, the end of the electrode 226 is located outside the oxide semiconductor film 208. Alternatively, a channel In the width direction, the electrode 226 extends beyond the edge of the oxide semiconductor film 208 via the protective film 141. It is provided in such a way. Also, in the channel width direction, on the outside of the oxide semiconductor film 208, The gate electrode 206 and electrode 226 are opposite each other via the gate insulating film 207 and protective film 141. do.

[0291] Using Figure 14(C), the ends of the gate electrode 206, oxide semiconductor film 208, and electrode 226 Let me explain the location.

[0292] Here, let d be the distance between the edge of the oxide semiconductor film 208 and the edge of the electrode 226, and the protective film 1 If the thickness of 41 is t, then it is preferable that d is less than or equal to the thickness of the protective film 141. By making the distance d between the end of the body membrane 208 and the end of the electrode 226 less than or equal to the distance t of the protective membrane 141, It is possible to apply the influence of the electric field of electrode 226 to the edge of oxide semiconductor film 208. The entire oxide semiconductor film 208, including its edges, can be made to function as a channel.

[0293] The edges of the oxide semiconductor film 208, which has been processed by etching, etc., are damaged during processing. As defects are formed and contamination occurs due to impurity adhesion, etc., stress such as electric fields occurs. It is easily activated when given. That is, oxide semiconductors processed by etching, etc. The edges of a conductive film tend to become n-type (low-resistance).

[0294] In this way, the n-type region is unintentionally formed between the source electrode 209a and the drain electrode 209 When it comes into contact with b, a certain area is intended between the source electrode 209a and the drain electrode 209b via that region. An unintended current (also called "leakage current") flows. This region functions as a parasitic channel.

[0295] However, as shown in Figure 14(C), the gate electrode 2 is located on the outside of the oxide semiconductor film 208. Due to the position of the end of 06, the oxide semiconductor film 2 is affected by the electric field of the gate electrode 206. The development of parasitic channels is suppressed at the lateral surface of 08, or at the end including the lateral surface and its vicinity. As a result, the rise in drain current becomes steep when the gate voltage exceeds the threshold voltage. This allows for the creation of transistors with excellent electrical characteristics.

[0296] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0297] (Embodiment 5) In this embodiment, transistors 231, 233, and 43 The configuration of transistor 200, which can be used in applications such as 1, will be explained using Figure 15. ru.

[0298] Figure 15(A) is a top view of transistor 200. Also, Figure 15(B) is a top view of Figure 15(A). Figure 15(C) is a cross-sectional view of the area indicated by the dashed line X3-X4 in Figure 15(A). This is a cross-sectional view of the region indicated by the dashed line Y3-Y4. Figure 15(B) shows a transistor. Figure 15(C) shows a cross-section of transistor 200 in the channel length direction. This is a cross-section in the width direction.

[0299] Transistor 200 is manufactured in the same manner as transistor 431 described in the above embodiment. This is possible. However, transistors 200 and 431 use an oxide semiconductor film 2 The shapes of 08 and gate electrode 206 are different.

[0300] Transistor 200 has gate current not only in the channel width direction but also in the channel length direction. The end of pole 206 is positioned outside the end of the oxide semiconductor film 208. See Figure 15(B). The gate electrode 206 is connected to an oxide semiconductor film 2 at the end of the gate electrode 206. By positioning it outside the end of 08, the electrical characteristics of the transistor due to light irradiation This can further suppress gender variability.

[0301] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0302] (Embodiment 6) In this embodiment, transistors 231, 233, and 43 The configuration of transistor 250, which can be used in applications such as 1, will be explained using Figure 16. ru.

[0303] Figure 16(A) is a top view of transistor 250. Also, Figure 16(B) is a top view of Figure 16(A). Figure 16(C) is a cross-sectional view of the area indicated by the dashed line X5-X6 in Figure 16(A). This is a cross-sectional view of the area indicated by the dashed line Y5-Y6. Figure 16(D) is shown in Figure 16(B). This is a magnified view of part 290. Figure 16(B) shows the channel length of transistor 250. Figure 16(C) shows a cross-section in the direction of the channel width of transistor 250.

[0304] Transistor 250 is manufactured in the same manner as transistor 431 described in the above embodiment. This is possible. However, the transistor 250 is in contact with the oxide semiconductor film 208. A conductive film 218 is formed. Also, in transistor 250, as a back gate electrode Although a functional electrode 226 is not provided, an electrode 226 may be provided if necessary. Needless to say.

[0305] The oxide semiconductor film 218 is composed of one or more of the metal elements that make up the oxide semiconductor film 208. This is an oxide film. Therefore, the boundary between the oxide semiconductor film 208 and the oxide semiconductor film 218 Interfacial scattering is less likely to occur on the surface. Therefore, carrier movement is inhibited at the interface. Because this does not occur, the field effect mobility becomes higher.

[0306] Oxide semiconductor films 218 are typically In-Ga oxide, In-Zn oxide, and In-M - A Zn oxide (where M is Al, Ga, Y, Zr, La, Ce, or Nd), and also oxidized The energy at the lower end of the conduction band is closer to the vacuum level than that of the monocrystalline semiconductor film 208, and typically, oxidation The energy at the lower end of the conduction band of the monocrystalline semiconductor film 218 and the energy at the lower end of the conduction band of the oxide semiconductor film 208 The difference from the energy is 0.05 eV or more, 0.07 eV or more, 0.1 eV or more, or 0.15 eV or higher, and 2 eV or lower, 1 eV or lower, 0.5 eV or lower, or 0.4 eV or lower Below. That is, the electron affinity of the oxide semiconductor film 218 and the electron affinity of the oxide semiconductor film 208. The difference from the sum is 0.05 eV or more, 0.07 eV or more, 0.1 eV or more, or 0.15 eV. eV or greater, and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less. .

[0307] The oxide semiconductor film 218 has a higher carrier mobility (electron mobility) when it contains In. preferable.

[0308] As the oxide semiconductor film 218, Al, Ga, Y, Zr, La, Ce, or Nd is used in In Having a high atomic ratio may have the following effects: (1) Oxide semiconductor film 2 (2) Increase the energy gap of 18. Reduce the electron affinity of the oxide semiconductor film 218. (3) Reduces the diffusion of impurities from the outside. (4) Compared with oxide semiconductor film 208 This increases the insulating properties. Also, Ga, Y, Zr, La, Ce, or Nd bond with oxygen. Because it is a metallic element with a strong resultant force, Ga, Y, Zr, La, Ce, or Nd are stronger than In. Having a specific atomic ratio makes oxygen deficiency less likely to occur.

[0309] When the oxide semiconductor film 218 is an In-M-Zn oxide, the sum of In and M is 100a When expressed as tomic%, the atomic ratio of In to M is preferably such that In is 50 atoms. Less than %, M is 50 atomic% or more, more preferably In is 25 atomic% or less Full, M must be 75% or higher.

[0310] Furthermore, oxide semiconductor film 208 and oxide semiconductor film 218 are In-M-Zn oxide (M For Ga, Y, Zr, La, Ce, or Nd, compared to oxide semiconductor film 208 The original M (Ga, Y, Zr, La, Ce, or Nd) contained in the oxide semiconductor film 218 The atom ratio is large, and typically, compared to the above atoms contained in oxide semiconductor film 208, 1 The atomic ratio is 0.5 times or higher, preferably 2 times or higher, and more preferably 3 times or higher.

[0311] Furthermore, oxide semiconductor film 208 and oxide semiconductor film 218 are In-M-Zn oxide (M If the oxide semiconductor film 218 is made of Al, Ga, Y, Zr, La, Ce, or Nd, then I n:M:Zn=x1:y1:z1 [atomic ratio], oxide semiconductor film 208 is In:M:Zn If we set the ratio of atoms to x2:y2:z2, then y1 / x1 is greater than y2 / x2, which is preferable. Alternatively, y1 / x1 is 1.5 times or more than y2 / x2. More preferably, y1 / x1 is at least twice as large as y2 / x2, and more preferably, y1 / x1 is greater than y2 / x2 It is more than three times larger. In this case, in an oxide semiconductor film, if y2 is x2 or greater, This is preferable because it can impart stable electrical characteristics to transistors using oxide semiconductor films. Furthermore, when y2 becomes more than three times x2, the electric field of the transistor using the oxide semiconductor film in question Since the effective mobility decreases, it is preferable that y2 is less than 3 times x2.

[0312] Oxide semiconductor film 208 is In-M-Zn oxide (where M is Ga, Y, Zr, La, Ce, ma In the case of Nd, the target used to deposit the oxide semiconductor film 208 is, If the atomic ratio of the metal elements is In:M:Zn=x1:y1:z1, then 、 x1 / y1 is 1 / 3 to 6, and moreover 1 to 6, and z1 / y1 is 1 / 3 to 6, and further It is preferable that z1 / y1 be between 1 and 6. This facilitates the formation of the CAAC-OS film as the oxide semiconductor film 208. Typical examples of atomic ratios of group elements are In:M:Zn=1:1:1 and In:M:Zn=5 Examples include :5:6, In:M:Zn=2:1:2, In:M:Zn=3:1:2, etc.

[0313] The oxide semiconductor film 218 is In-M-Zn oxide (where M is Ga, Y, Zr, La, Ce, ma In the case of Nd, the target used to deposit the oxide semiconductor film 218 is, If the atomic ratio of the metal elements is In:M:Zn = x²:y²:z², then 、 x2 / y2 <x1 / It is preferable that y1 is such that z2 / y2 is between 1 / 3 and 6, and moreover, between 1 and 6. It seems so. Furthermore, by setting z2 / y2 to between 1 and 6, the oxide semiconductor film 218 can be made C AAC-OS film formation becomes easier. Typical examples of atomic ratios of target metal elements include... are In:M:Zn=1:3:2, In:M:Zn=1:3:4, In:M:Zn=1: Examples include 3:6 and In:M:Zn=1:3:8.

[0314] Note that the atomic ratios of oxide semiconductor film 208 and oxide semiconductor film 218 are, respectively, error. This includes variations of plus or minus 40% in the above atomic ratio.

[0315] The thickness of the oxide semiconductor film 218 is 3 nm or more and 100 nm or less, preferably 3 nm or more and 50 nm or less. Let's use nm.

[0316] Furthermore, the oxide semiconductor film 218, like the oxide semiconductor film 208, can, for example, have a non-single crystal structure. This is also acceptable. Note that non-single-crystal structures include CAAC structures, polycrystalline structures, microcrystalline structures, or amorphous structures. Includes structure.

[0317] The oxide semiconductor film 218 may have an amorphous structure, for example. An amorphous oxide semiconductor film is For example, an oxide film with a disordered atomic arrangement and no crystalline components, or an amorphous structure. For example, it has a completely amorphous structure and does not contain any crystalline parts.

[0318] Furthermore, the oxide semiconductor film 208 and the oxide semiconductor film 218 create regions with an amorphous structure. It has regions of microcrystalline structure, polycrystalline structure, CAAC structure, and two or more single-crystal structures. A mixed film may be formed, for example, a region with an amorphous structure and a region with a microcrystalline structure. , two or more of the following regions: polycrystalline structure region, CAAC structure region, single crystal structure region It may have such a feature. Furthermore, the mixed film may have, for example, regions with an amorphous structure, regions with a microcrystalline structure, Two or more regions of the following types: polycrystalline structure, CAAC structure, and single crystal structure. It may have a layered structure.

[0319] Here, an oxide semiconductor film 218 is provided between the oxide semiconductor film 208 and the insulating film 108. Therefore, impurities are present between the oxide semiconductor film 218 and the insulating film 108. Even if a trap level is formed due to a defect, the said trap level and the oxide semiconductor film 208 There is a gap between them. As a result, electrons flowing through the oxide semiconductor film 208 are trapped at the trap level. It is less likely to be captured by electric fields, and it is possible to increase the on-current of the transistor, as well as the electric field. The effective mobility can be increased. Also, when an electron is trapped at the trap level, the electron This results in a negative fixed charge. As a result, the transistor's threshold voltage fluctuates. However, there is a gap between the oxide semiconductor film 208 and the trap level. This makes it possible to reduce electron trapping at the trap level and to control the fluctuation of the threshold voltage. It can be reduced.

[0320] Furthermore, the oxide semiconductor film 218 can shield against external impurities, It is possible to reduce the amount of impurities that move from the part to the oxide semiconductor film 208. The oxide semiconductor film 218 is less likely to form oxygen vacancies. For these reasons, the oxide semiconductor film 208 It is possible to reduce the impurity concentration and oxygen deficiency in the mixture.

[0321] Furthermore, the oxide semiconductor film 208 and the oxide semiconductor film 218 are not simply stacked together. No continuous junction (here in particular, a structure in which the energy at the lower end of the conduction band changes continuously between each film) The film is fabricated so that a trap center or re-bonding structure is formed at the interface of each film. The layered structure is designed so that there are no impurities that form defect levels such as intercalation centers. Furthermore, impurities are mixed between the stacked oxide semiconductor film 208 and oxide semiconductor film 218. If this occurs, the continuity of the energy bands is lost, carriers are trapped at the interface, or They recombine and then disappear.

[0322] To form continuous bonds, a multi-chamber deposition apparatus equipped with a load-lock chamber is required. (Using a sputtering device) to continuously stack each film without exposing it to the atmosphere. This is necessary. Each chamber in the sputtering apparatus is inefficient for oxide semiconductor films. An adsorption-type vacuum exhaust pump such as a cryopump should be used to remove pure substances such as water as much as possible. High-vacuum exhaust (up to about 5×10 -7 Pa to 1×10 -4 Pa) is preferably carried out. Or, it is preferable to combine a turbo molecular pump and a cold trap so that gas, particularly gas containing carbon or hydrogen, does not flow back into the chamber from the exhaust system. Or, it is preferable to combine a turbo molecular pump and a cold trap so that gas, particularly gas containing carbon or hydrogen, does not flow back into the chamber from the exhaust system. Or, it is preferable to combine a turbo molecular pump and a cold trap so that gas, particularly gas containing carbon or hydrogen, does not flow back into the chamber from the exhaust system. .

[0323] Also, in the formation process of the source electrode 209a and the drain electrode 209b, the surface of the oxide semiconductor film 218 may be etched.

[0324] 〔Band structure diagram〕 Fig. 17 is a diagram schematically showing the band structure of the portion indicated by the dashed-dotted line Z1-Z2 in Fig. 16(D). EcI1 shown in Fig. 17 indicates the energy at the lower end of the conduction band of the gate insulating film 207, EcS1 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 208, EcS2 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 218, and EcI2 indicates the energy at the lower end of the conduction band of the insulating film 108. Fig. 17 is a diagram schematically showing the band structure of the portion indicated by the dashed-dotted line Z1-Z2 in Fig. 16(D). EcI1 shown in Fig. 17 indicates the energy at the lower end of the conduction band of the gate insulating film 207, EcS1 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 208, EcS2 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 218, and EcI2 indicates the energy at the lower end of the conduction band of the insulating film 108. Fig. 17 is a diagram schematically showing the band structure of the portion indicated by the dashed-dotted line Z1-Z2 in Fig. 16(D). EcI1 shown in Fig. 17 indicates the energy at the lower end of the conduction band of the gate insulating film 207, EcS1 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 208, EcS2 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 218, and EcI2 indicates the energy at the lower end of the conduction band of the insulating film 108. Fig. 17 is a diagram schematically showing the band structure of the portion indicated by the dashed-dotted line Z1-Z2 in Fig. 16(D). EcI1 shown in Fig. 17 indicates the energy at the lower end of the conduction band of the gate insulating film 207, EcS1 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 208, EcS2 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 218, and EcI2 indicates the energy at the lower end of the conduction band of the insulating film 108. Fig. 17 is a diagram schematically showing the band structure of the portion indicated by the dashed-dotted line Z1-Z2 in Fig. 16(D). EcI1 shown in Fig. 17 indicates the energy at the lower end of the conduction band of the gate insulating film 207, EcS1 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 208, EcS2 indicates the energy at the lower end of the conduction band of the oxide semiconductor film 218, and EcI2 indicates the energy at the lower end of the conduction band of the insulating film 108.

[0325] As shown in Fig. 17, at the junction of the oxide semiconductor film 208 and the oxide semiconductor film 218, the energy at the lower end of the conduction band changes smoothly. In other words, it can be said that it changes continuously. This is because the oxide semiconductor film 208 and the oxide semiconductor film 218 contain a common metal element, and an oxygen mixed layer is formed by the mutual movement of oxygen between the oxide semiconductor film 208 and the oxide semiconductor film 218. metal element, and an oxygen mixed layer is formed by the mutual movement of oxygen between the oxide semiconductor film 208 and the oxide semiconductor film 218.

[0326] From Fig. 17, the oxide semiconductor film 208 becomes a well, and the channel region is an oxide semiconductor It can be seen that it is formed on the body film 208. Note that the oxide semiconductor film 208 and the oxide semiconductor Because the energy at the lower end of the conduction band of film 218 is continuously changing, the oxide semiconductor film 20 It can also be said that 8 and the oxide semiconductor film 218 are continuously bonded together.

[0327] Furthermore, in the process of forming the source electrode 209a and the drain electrode 209b, The surface of the body film 218 may be etched. Therefore, the oxide semiconductor film 218 is insulated. Trap levels can form near the interface with film 108 due to impurities or defects. However, While providing the oxide semiconductor film 218, the oxide semiconductor film 208 and the The lap level can be moved away. However, the energy difference between EcS1 and EcS2 ( When dEcS) is small, electrons in the oxide semiconductor film 208 trap beyond this energy difference. The electrons can reach the trap level. When electrons are trapped at the trap level, a mycelium is created at the insulating film interface. A fixed charge is generated in the eggplant, causing the transistor's threshold voltage to shift in the positive direction. Therefore, the energy difference between EcS1 and EcS2 (dEcS) should be 0.1 eV or greater. Setting it to 0.15eV or higher reduces the fluctuation in the transistor's threshold voltage, making it safer. It is suitable because it provides stable electrical characteristics.

[0328] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0329] (Embodiment 7) In this embodiment, an example of the configuration of a light-emitting element that can be used in the light-emitting element 125 will be described. In addition, the EL layer 320 shown in this embodiment is the same as the EL layer 117 shown in other embodiments. It corresponds to this.

[0330] <Configuration of light-emitting elements> The light-emitting element 330 shown in Figure 18(A) has an EL between a pair of electrodes (electrode 318, electrode 322). It has a structure in which layer 320 is sandwiched. In the following description of this embodiment, Electrode 318 is used as the anode, and electrode 322 is used as the cathode.

[0331] Furthermore, the EL layer 320 only needs to include at least an emissive layer, and other than the emissive layer... It may also be a laminated structure including a functional layer. The functional layer other than the light-emitting layer may have high hole injection properties. Materials, materials with high hole transport, materials with high electron transport, materials with high electron injection, bipods A layer containing materials with high electron and hole transport properties can be used. In this case, functional layers such as hole injection layers, hole transport layers, electron transport layers, and electron injection layers are appropriately combined. It can be used.

[0332] The light-emitting element 330 shown in Figure 18(A) reacts to the potential difference generated between electrode 318 and electrode 322. As more current flows, holes and electrons recombine in the EL layer 320, causing light to be emitted. In other words, the EL layer 320 is configured in such a way that an emitting region is formed therein.

[0333] In the present invention, the light emitted from the light-emitting element 330 is emitted from the electrode 318 or electrode 322 side. It is removed to the part. Therefore, either electrode 318 or electrode 322 has light-transmitting properties. It is made up of such substances.

[0334] Furthermore, the EL layer 320 has electrodes 318 and 3, as shown in Figure 18(B) for the light-emitting element 331. Multiple layers may be stacked between 22 and other elements. It has a stacked structure of n layers (where n is a natural number greater than or equal to 2). In the case where, the m-th (m is a natural number satisfying 1 ≦ m < n) EL layer 320 and the (m + 1) th EL layer 320, it is preferable to provide charge generation layers 320a therebetween, respectively.

[0335] The charge generation layer 320a includes a composite material of an organic compound and a metal oxide, a metal oxide, a composite material of an organic compound and an alkali metal, an alkaline earth metal, or a compound thereof, and in addition, these can be formed by appropriately combining them. As the composite material of an organic compound and a metal oxide, for example, it includes a composite material of an organic compound and a metal oxide such as vanadium oxide, molybdenum oxide, tungsten oxide, etc. As the organic compound, aromatic amine compounds, carbazole derivatives, low molecular weight compounds such as aromatic hydrocarbons, or oligomers, dendrimers, polymers, etc. of these low molecular weight compounds, and various compounds can be used. As the organic compound, a hole transport organic compound having a hole mobility of 10 cm / Vs or more is preferably applied. However, as long as it is a substance with higher hole transportability than electrons, other substances can be used. -6 cm 2 / Vs or more is preferably applied. However, as long as it is a substance with higher hole transportability than electrons, other substances can be used. In addition, since these materials used for the charge generation layer 320a are excellent in carrier injection property and carrier transport property, low current driving and low voltage driving of the light emitting element 330 can be realized. transport property, low current driving and low voltage driving of the light emitting element 330 can be realized. Since these materials used for the charge generation layer 320a are excellent in carrier injection property and carrier transport property, low current driving and low voltage driving of the light emitting element 330 can be realized.

[0336] In addition, the charge generation layer 320a may be formed by combining a composite material of an organic compound and a metal oxide with other materials. For example, a layer containing a composite material of an organic compound and a metal oxide and a layer containing one compound selected from electron donors and a compound having high electron transportability may be combined and formed. Further, a layer containing a composite material of an organic compound and a metal oxide and a transparent conductive film selected from among electron donors and a compound having high electron transportability may be combined and formed. Further, a layer containing a composite material of an organic compound and a metal oxide and a transparent conductive film may be combined and formed. They may be formed by combining them.

[0337] A light-emitting element 331 having such a configuration may experience problems such as energy transfer and quenching. This makes it difficult to create light-emitting elements that combine high luminous efficiency and long lifespan by expanding the range of material choices. It is easy to do so. Furthermore, it is also easy to obtain phosphorescence in one light-emitting layer and fluorescence in the other. That is the case.

[0338] The charge generation layer 320a is a layer that generates charge when a voltage is applied to electrodes 318 and 322. It has the function of injecting holes into one of the EL layers 320 that is formed in contact with the generation layer 320a. It also has the function of injecting electrons into the other EL layer 320.

[0339] The light-emitting element 331 shown in Figure 18(B) can be modified by changing the type of light-emitting material used in the EL layer 320. This allows for obtaining various emission colors. In addition, multiple luminescent materials with different emission colors can be used. By using luminescent materials, it is also possible to obtain emission with a broad spectrum or white light emission. ru.

[0340] When obtaining white light emission using the light-emitting element 331 shown in Figure 18(B), a combination of multiple EL layers is used. The combination can be any configuration that emits white light including red, blue, and green light, for example. A light-emitting layer containing a blue fluorescent material as a light-emitting substance, and a layer containing green and red phosphorescent materials as light-emitting substances One example is a configuration having a light-emitting layer containing a red light-emitting layer and a green light-emitting layer. It is also possible to have a configuration having an emissive layer that shows light emission and an emissive layer that shows blue light emission. Alternatively, White light emission can be obtained even with a configuration that has a light-emitting layer that emits light of complementary colors. In a stacked element with two layers stacked, the emission color of the light emitted from the light-emitting layer and the light emitted from the light-emitting layer When the colors of the emitted light are to be complementary, the complementary colors would be blue and yellow, or Examples include blue-green and red.

[0341] Furthermore, in the configuration of the stacked element described above, a charge generation layer is placed between the stacked light-emitting layers. By doing so, it is possible to achieve long-life elements in the high-brightness region while keeping the current density low. Yes, it is possible. Furthermore, the voltage drop due to the resistance of the electrode material can be reduced, allowing for uniform generation over a large area. Light becomes possible.

[0342] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination.

[0343] (Embodiment 8) This embodiment provides examples of electronic devices and lighting devices to which a display device according to one aspect of the present invention is applied. Then, I will explain by referring to the drawings.

[0344] As an electronic device that applies a display device with a flexible shape, for example, television Devices (also called televisions or television receivers), monitors for computers, etc. Digital cameras, digital video cameras, digital photo frames, mobile phones (mobile phones, (Also called mobile phone devices), portable game consoles, personal information terminals, sound playback devices, pachinko machines, etc. Examples include large game consoles.

[0345] Furthermore, lighting devices and display devices can be installed on the interior or exterior walls of houses and buildings, or on the interior or exterior of automobiles. It can also be incorporated along curved surfaces.

[0346] Figure 19(A) shows an example of a mobile phone. Mobile phone 7400 has a housing 7401 In addition to the display unit 7402 incorporated into it, there are operation buttons 7403, an external connection port 7404, and It is equipped with a speaker 7405, a microphone 7406, etc. Note that the mobile phone 7400 has a display. The device is manufactured by using it in the display unit 7402.

[0347] The mobile phone 7400 shown in Figure 19(A) allows information to be conveyed by touching the display unit 7402 with a finger or the like. You can enter information. You can also make phone calls or type text. The operation can be performed by touching the display unit 7402 with a finger or the like.

[0348] Furthermore, by operating the control button 7403, the power can be turned ON or OFF, and the display unit 7402 will show... You can switch the type of image displayed. For example, from the email composition screen, the main menu - You can switch to a different screen.

[0349] Here, the display unit 7402 incorporates a display device according to one aspect of the present invention. This allows for a mobile phone with a curved display and high reliability.

[0350] Figure 19(B) shows an example of a wristband-type display device. Portable display device 7100 It comprises a housing 7101, a display unit 7102, operation buttons 7103, and a transmitting / receiving device 7104. El.

[0351] The portable display device 7100 is capable of receiving video signals by the transceiver 7104, and the received The video can be displayed on the display unit 7102. Additionally, the audio signal can be transmitted to other receiving devices. It is also possible to do so.

[0352] Additionally, the 7103 control button allows you to turn the power on and off and switch the displayed image. You can also adjust the volume of the sound, etc.

[0353] Here, the display unit 7102 incorporates a display device according to one aspect of the present invention. This allows for the creation of a highly reliable portable display device equipped with a curved display section.

[0354] Figures 19(C) to 19(E) show an example of a lighting device. Lighting device 7200, lighting The lighting device 7210 and the illumination device 7220 each have a base 72 equipped with an operating switch 7203. It has part 01 and a light-emitting part supported by the base part 7201.

[0355] The lighting device 7200 shown in Figure 19(C) includes a light-emitting section 7202 having a wave-shaped light-emitting surface. Therefore, it is a lighting fixture with a highly aesthetic design.

[0356] The light-emitting section 7212 of the lighting device 7210 shown in Figure 19(D) has two convexly curved parts The light-emitting parts are arranged symmetrically. Therefore, the entire lighting system is centered around the lighting device 7210. It can illuminate directions.

[0357] The lighting device 7220 shown in Figure 19(E) includes a concavely curved light-emitting section 7222. Therefore, in order to concentrate the light emitted from the light-emitting unit 7222 onto the front of the lighting device 7220, It is suitable for brightly illuminating a wide area.

[0358] Furthermore, each of the light-emitting parts provided in the lighting device 7200, lighting device 7210, and lighting device 7220 Because it is flexible, the light-emitting part can be made of a plastic material or a movable frame. The component may be fixed in place, and the light-emitting surface of the light-emitting part may be freely curved to suit the application.

[0359] Here, the light emission provided by each of the lighting devices 7200, 7210, and 7220 The section incorporates a display device according to one aspect of the present invention. Therefore, the curved display section This allows for the creation of a reliable and robust lighting system.

[0360] Figure 20(A) shows an example of a portable display device. The display device 7300 is housed in a casing 7301. It comprises a display unit 7302, operation buttons 7303, a pull-out member 7304, and a control unit 7305. .

[0361] The display device 7300 has a flexible display unit wound in a roll inside a cylindrical housing 7301. It is equipped with 7302.

[0362] Furthermore, the display device 7300 can receive video signals via the control unit 7305, and the received video This can be displayed on the display unit 7302. The control unit 7305 is also equipped with a battery. Furthermore, the control unit 7305 is equipped with a connector, allowing for a configuration in which video signals and power are supplied directly. good.

[0363] Additionally, the 7303 control button allows you to turn the power on and off and switch the displayed image. These can be done.

[0364] Figure 20(B) shows the display unit 7302 pulled out by the pull-out member 7304. In this state, an image can be displayed on the display unit 7302. Also, on the surface of the housing 7301 The positioned control buttons 7303 allow for easy one-handed operation.

[0365] Furthermore, to prevent the display unit 7302 from bending when it is pulled out, the display unit 730 A reinforcing frame may be provided at the end of section 2.

[0366] In addition to this configuration, a speaker is installed in the enclosure, and the audio signal received along with the video signal is used. It may also be configured to output sound.

[0367] The display unit 7302 incorporates a display device according to one aspect of the present invention. Therefore, the display Since part 7302 is a flexible and reliable display device, the display device 7300 is This allows for a lightweight and highly reliable display device.

[0368] Furthermore, if a display device according to one aspect of the present invention is provided, the electronic devices and lighting devices described above will be used. Needless to say, this is not limited to any particular category.

[0369] The configurations and methods shown in this embodiment may be appropriately combined with the configurations and methods shown in other embodiments. They can be used in combination. [Explanation of Symbols]

[0370] 100 display device 101 Element Formation Substrate 108 Insulating Film 109 Insulating film 110 Insulating Film 111 circuit board 112 Adhesive layer 113 Exfoliation layer 114 Bulkhead 115 Electrode 116 Terminal electrode 117 EL layer 118 Electrode 119 Base layer 120 Adhesive layer 121 circuit boards 122 Opening 123 Anisotropic conductive connecting layer 124 External electrode 125 Light-emitting element 131 Display area 132 Drive Circuit 133 Drive Circuit 134 pixels 135 scan lines 136 signal line 141 Protective film 142 Opening 143 Opening 145 Conductive film 150 Display device

Claims

[Claim 1] The device comprises a transistor having a translucent semiconductor film on a flexible substrate, a capacitive element with a dielectric film provided between a first electrode and a second electrode, and an insulating film covering the semiconductor film. The capacitive element has a region in which the first electrode and the dielectric film are in contact, The display device is characterized in that the insulating film does not cover the region.

Images