Display device

Abstract

Provided is a highly reliable display device. Also provided is a display device in which photodegradation of a transistor is suppressed. The display device includes a first transistor of a vertical transistor, a second transistor of a top gate type transistor, a first insulating layer, and a first conductive layer. The first transistor includes an upper electrode and a lower electrode. The upper electrode and the second transistor are located on the first insulating layer. The first conductive layer has a region overlapping the second transistor below the first insulating layer. The first conductive layer and the lower electrode are located on the same plane and contain the same material.

Description

Technical Field

[0001] One aspect of the present invention relates to a semiconductor device. Another aspect of the present invention relates to a transistor. Another aspect of the present invention relates to a display device including a transistor.

[0002] Note that one aspect of the present invention is not limited to the technical fields described above. Examples of technical fields encompassing one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, methods for driving these devices, and methods for manufacturing these devices. A semiconductor device refers to any device capable of operating by utilizing the characteristics of semiconductors. Background Technology

[0003] As a type of display device, there are liquid crystal display devices that use liquid crystal elements as display elements. For example, active matrix liquid crystal display devices, in which pixel electrodes are arranged in a matrix and each pixel electrode is connected to a switching element, are used in various devices such as smartphones, tablets, displays, televisions, and digital signage.

[0004] Liquid crystal display devices are generally classified into two types: transmissive and reflective. A higher effective light-emitting area ratio (also known as aperture ratio) of pixels in a liquid crystal display device results in a brighter display and lower power consumption; therefore, increasing the aperture ratio is required.

[0005] For example, active matrix liquid crystal display devices are known that use transistors with metal oxide as the channel formation region as switching elements connected to the electrodes of each pixel. Patent Document 1 discloses a liquid crystal display device that uses transistors with metal oxide as the channel formation region to improve the aperture ratio.

[0006] [Preliminary Technology Documents] [Patent Literature] [Patent Document 1] Japanese Patent Application Publication No. 2018-189938. Summary of the Invention

[0007] The technical problem that the invention aims to solve One objective of this invention is to provide a display device with high reliability. Another objective of this invention is to provide a display device that suppresses light degradation in transistors. One objective of this invention is to provide a display device with high display quality. Another objective of this invention is to provide a display device with a high aperture ratio. Another objective of this invention is to provide a display device capable of high-speed driving.

[0008] One objective of this invention is to provide a display device, transistor, electronic device, etc., with a novel structure. Another objective of this invention is to improve at least one of the problems of the prior art.

[0009] Note that the description of these objectives does not preclude the existence of other objectives. Also note that one embodiment of the invention does not necessarily require achieving all of the above objectives. Furthermore, objectives other than those described above can be extracted from the description in the specification, drawings, claims, etc.

[0010] means of solving technical problems One aspect of the present invention is a display device comprising a first transistor with a vertical transistor, a second transistor with a top-gate transistor, a first insulating layer, and a first conductive layer. The first transistor includes an upper electrode and a lower electrode. The upper electrode and the second transistor are located on the first insulating layer. The first conductive layer has a region located below the first insulating layer and overlapping with the second transistor. The first conductive layer and the lower electrode are located on the same surface and comprise the same material.

[0011] Furthermore, in the aforementioned display device, it is preferable that the first transistor includes a first semiconductor layer and the second transistor includes a second semiconductor layer. In this case, the first conductive layer is preferably disposed in a manner that overlaps with the second semiconductor layer. Additionally, the first semiconductor layer and the second semiconductor layer preferably have portions located on the same surface and contain the same material.

[0012] Furthermore, the display device described above preferably includes a display element connected to the second transistor. In this case, the display element is preferably a liquid crystal element. Alternatively, the display element is preferably a light-emitting element.

[0013] Invention Effects According to one aspect of the present invention, a display device with high reliability can be provided. Additionally, a display device in which transistor light degradation is suppressed can be provided. Furthermore, a display device with high display quality can be provided. Furthermore, a display device with high aperture ratio can be provided. Furthermore, a display device capable of high-speed driving can be provided.

[0014] According to one aspect of the present invention, a display device, transistor, electronic device, etc., with a novel structure can be provided. According to one aspect of the present invention, at least one of the problems in the prior art can be improved.

[0015] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the invention does not necessarily require all of the aforementioned effects. Furthermore, effects other than those described above can be extracted from the description in the specification, drawings, claims, etc.

[0016] Brief description of the attached figures Figure 1Aand Figure 1B This is an example of the structure of a display device.

[0017] Figure 2A and Figure 2B This is an example of the structure of a display device.

[0018] Figures 3A to 3D This is an example of the structure of a display device.

[0019] Figures 4A to 4D This is an example of the structure of a display device.

[0020] Figures 5A to 5C This is an example of the structure of a display device.

[0021] Figures 6A to 6D This is an example of the structure of a display device.

[0022] Figures 7A to 7C This is an example of the structure of a display device.

[0023] Figures 8A to 8D This is an example of the structure of a display device.

[0024] Figures 9A to 9E This is an example of the structure of a display device.

[0025] Figure 10A and Figure 10B This is an example of the structure of a display device.

[0026] Figures 11A to 11E This is an example of the structure of a display device.

[0027] Figures 12A to 12E This is an example of the structure of a display device.

[0028] Figures 13A to 13D This is an example of the structure of a display device.

[0029] Figures 14A to 14E This is an example of the structure of a display device.

[0030] Figures 15A to 15D This is an example of the structure of a display device.

[0031] Figures 16A to 16C This is an example of the structure of a display device.

[0032] Figures 17A to 17D This is an example of pixel structure.

[0033] Figures 18A to 18D This is an example of pixel structure.

[0034] Figure 19 This is an example of pixel structure.

[0035] Figures 20A to 20D This is an example of the structure of an electronic device.

[0036] Figures 21A to 21F This is an example of the structure of an electronic device.

[0037] Figures 22A to 22G This is an example of the structure of an electronic device.

[0038] Methods of implementing the invention The embodiments will now be described with reference to the accompanying drawings. However, those skilled in the art will readily understand that the embodiments can be implemented in many different forms, and their manner and details can be varied in various ways without departing from the spirit and scope of the invention. Therefore, the invention should not be construed as being limited to the contents described in the embodiments shown below.

[0039] Note that in the structure of the invention described below, the same symbols are used in different figures to represent the same parts or parts with the same function, and repeated descriptions are omitted. Furthermore, when representing parts with the same function, the same shading lines are sometimes used without additional symbols.

[0040] Note that in the various figures described in this specification, the size of the constituent elements, the thickness of the layers, and the area are sometimes exaggerated for clarity. Therefore, the present invention is not limited to the dimensions shown in the figures.

[0041] The ordinal numbers such as "first" and "second" used in this specification are appended to avoid confusion of the constituent elements, and are not intended to limit the quantity.

[0042] A transistor is a type of semiconductor device that can amplify current or voltage, control switching operations (turning on or off), etc. The transistors discussed in this specification include IGFETs (Insulated Gate Field Effect Transistors) and thin-film transistors (TFTs).

[0043] Furthermore, in cases where transistors with different polarities are used or the current direction changes during circuit operation, the functions of the "source" and "drain" are sometimes interchanged. Therefore, in this specification, the "source" and "drain" can be used interchangeably.

[0044] Furthermore, in this specification, "electrical connection" includes connections made via "elements that have a certain electrical function." Here, there are no particular limitations on what constitutes an "element that has a certain electrical function," as long as it allows for the transmission and reception of electrical signals between the connected objects. For example, "elements that have a certain electrical function" include, in addition to electrodes or wiring, switching elements such as transistors, resistors, coils, and other elements with various functions.

[0045] Note that in this specification, "electrical connection" does not include the case where two nodes are connected through insulators such as the dielectric of a capacitor element, the gate insulating film of a transistor, and the interlayer insulating film.

[0046] Note that in this specification, "generally consistent top surface shape" means that at least a portion of the outline of each layer in the stack overlaps. For example, this includes cases where the upper and lower layers, or portions thereof, are processed using the same mask pattern. However, there are actually cases where the outlines do not overlap, and sometimes the upper layer is inside or outside the lower layer; in such cases, it can also be said that the "top surface shape is generally consistent".

[0047] Note that in this specification, the top surface shape of a constituent element refers to the outline shape of the constituent element when viewed from a plane. Furthermore, "viewed from a plane" means the view taken from the normal direction of the surface on which the constituent element is formed or the surface of the support (e.g., a substrate) on which the constituent element is formed.

[0048] Note that the directions such as "up" and "down" will be used in accordance with the directions in the accompanying drawings in the following description. However, for the sake of simplicity, the directions indicated by "up" or "down" in the specification may sometimes differ from those in the accompanying drawings. As an example, when describing the stacking order (or formation order) of laminates, etc., even if the surface of one side of the laminate (the surface to be formed, the supporting surface, the adhesive surface, the flat surface, etc.) is located on the upper side of the laminate in the accompanying drawings, there may be cases where the surface to be formed is shown as "down" and the laminate side is shown as "up".

[0049] Furthermore, in this specification and other materials, the terms "film" and "layer" may be interchanged. For example, sometimes "insulating layer" and "insulating film" may be interchanged.

[0050] (Implementation Method 1) In this embodiment, a display device according to one aspect of the present invention will be described.

[0051] [Example of a display device structure] Figure 1A A block diagram of a display device 100 according to one embodiment of the present invention is shown. The display device 100 includes a pixel unit 101, a source line driving circuit unit 102, a gate line driving circuit unit 103, a protection circuit unit 104, and a touch sensor driving circuit unit 105.

[0052] Pixel section 101 is a region in which multiple pixels are arranged in a matrix, and each pixel contains at least one display element and pixel circuitry. The pixel circuitry is connected to at least one gate line and at least one source line. The pixel circuitry includes at least one transistor. Various components can be used as the display element. Typically, light-emitting elements such as organic EL elements and LED elements, liquid crystal elements, or MEMS (Micro Electro Mechanical Systems) elements can be used.

[0053] The source line drive circuit 102 is a circuit connected to the source line and outputting a signal to the source line. The source line drive circuit 102 may include one or more of a shift register circuit, a sampling switch, a latch circuit, an analog amplifier circuit, and a demultiplexer (DeMUX) circuit.

[0054] The gate line drive circuit section 103 is a circuit connected to the gate line and outputting a signal to the gate line. The gate line drive circuit may include a shift register circuit, an analog amplifier circuit, etc.

[0055] The protection circuit section 104 has the function of preventing damage to transistors and other components installed in the pixel circuit when surge voltages are applied to gate lines, source lines, capacitor lines, power lines, etc., due to static electricity. For example, a structure that releases charge to common wiring or the like when a surge voltage is applied can be used. The protection circuit can be composed of nonlinear elements arranged in parallel with wirings separated by a destination. The nonlinear elements are composed of two-terminal elements such as diodes or three-terminal elements such as transistors. For example, by connecting the gate terminal and drain terminal of a transistor, the transistor can have the same characteristics as a diode.

[0056] The touch sensor driving circuit 105 has the functions of outputting signals to drive a touch sensor disposed within or overlapping the pixel unit 101, and outputting signals input from the touch sensor. Various types of touch sensors can be used, such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, and optical sensors. In particular, capacitive or optical sensors are preferred. Note that the touch sensor driving circuit 105 may be omitted if a touch sensor is not required.

[0057] This invention describes a transistor that can be used in a display device according to one aspect of the present invention. The first is a transistor with a top-gate structure (hereinafter sometimes referred to as a TGSA transistor) having an oxide semiconductor layer disposed on a plane and a gate disposed on its top side. TGSA transistors can have a long channel length. Therefore, when the transistor operates in the saturation region, the change in source-drain current relative to the change in gate-source voltage can be minimized. For example, by using a TGSA transistor as a driving transistor included in a pixel circuit, the amount of current flowing through the light-emitting device can be tightly controlled. This increases the grayscale of the pixel circuit. Furthermore, a stable current can flow even if there are variations in the electrical characteristics (e.g., resistance) or non-uniformity of the electrical characteristics of the light-emitting device.

[0058] The second type is a transistor where the source and drain electrodes are located at different heights, and the current flowing through the semiconductor layer flows in the vertical direction. In other words, the channel length direction has a vertical component; therefore, a transistor according to one embodiment of the present invention can be referred to as a vertical transistor, a vertical-channel transistor, etc. Hereinafter, it will sometimes be referred to as a vertical transistor.

[0059] Vertical transistors allow for precise control of the channel length based on the thickness of the insulating layer used as a spacer between the source and drain electrodes. By forming a thin insulating layer, transistors with extremely short channel lengths can be formed, enabling transistors capable of carrying a large current (hereinafter also referred to as on-state current) in the on-state. Furthermore, by using oxide semiconductors as the semiconductor layer, leakage current in the off-state can be minimized. Therefore, vertical transistors are well-suited for use as switching elements.

[0060] The third is the use of crystalline silicon thin films in semiconductor transistors. Typically, low-temperature polysilicon (LTPS) can be used. Hereinafter referred to as LTPS transistors. LTPS transistors have high field-effect mobility, thus increasing the on-state current. Furthermore, LTPS transistors can be fabricated with both n-type and p-type transistors separately. Therefore, LTPS transistors can form CMOS circuits, enabling low power consumption when used in driver circuits, etc. Additionally, using p-type LTPS transistors as pixel driver transistors allows for more stable circuit operation compared to using only n-type transistors.

[0061] Alternatively, transistors that use monocrystalline silicon as the semiconductor can also be used. Transistors that use a portion of a monocrystalline silicon substrate as the semiconductor layer have extremely high field-effect mobility compared to LTPS transistors, and are therefore suitable for drive circuits that require high-speed operation (e.g., source line drive circuit 102, touch sensor drive circuit 105, etc.).

[0062] Compared to vertical transistors, TGSA transistors have lower parasitic capacitance. Compared to TGSA transistors, both vertical transistors and LTPS transistors have the ability to increase on-state current. LTPS transistors are easier to implement as p-channel transistors.

[0063] When the parasitic capacitance between the wirings constituting the pixel section 101 is large, the impact of noise between the wirings becomes greater, resulting in a decrease in display quality. Therefore, a TGSA transistor with small parasitic capacitance can be used in the pixel section 101. Alternatively, one or both of a TGSA transistor and an LTPS transistor can be used.

[0064] The gate line drive circuit section 103 is required to operate at high speed. Therefore, the gate line drive circuit section 103 preferably uses one or both of a vertical transistor and an LTPS transistor with a large on-state current.

[0065] The source line drive circuit 102 is required to operate at a higher speed than the gate line drive circuit 103. Therefore, the source line drive circuit 102 can use one or more of the following: a vertical transistor with a large on-state current, an LTPS transistor, and a transistor using single-crystal silicon.

[0066] The protection circuit section 104 can use any one of a vertical transistor, a TGSA transistor, or an LTPS transistor.

[0067] Similar to the gate line drive circuit 103, the touch sensor drive circuit 105 is also required to operate at high speed, so one or both of a vertical transistor and an LTPS transistor can be used.

[0068] The display device 100 can use two or more of vertical transistors, TGSA transistors, and LTPS transistors. In this case, it is preferable to manufacture the two or more transistors on the same substrate using the same process.

[0069] Here, the TGSA transistor used in the pixel section 101 may experience light degradation when illuminated by light used for image display. For example, when a liquid crystal element is used as a display element, when light emitted from the backlight shines on the semiconductor layer of the TGSA transistor, degradation of transistor characteristics (such as changes in threshold voltage) may occur. Therefore, it is preferable to use a light-shielding film overlapping the semiconductor layer. In this case, it is preferable to use a conductive film formed in the same process as the electrodes included in the vertical transistor as the light-shielding film overlapping the semiconductor layer of the TGSA transistor.

[0070] Figure 1B An example of a pixel circuit that can be used in the pixel section 101 is shown. Figure 1BAn example of using a liquid crystal element as a display element is shown. A pixel includes a transistor Tr, a capacitor C, and a liquid crystal element LC. Additionally, the pixel is connected to wirings GL, SL, and CL. Wiring GL is used as a gate line, wiring SL as a source line, and wiring CL is supplied with a fixed potential.

[0071] The gate of transistor Tr is connected to wiring GL, one of its source and drain is connected to wiring SL, and the other of its source and drain is connected to one electrode of capacitor C and one electrode of liquid crystal element LC. The other electrode of capacitor C is connected to wiring CL. The other electrode of liquid crystal element LC is used as a common electrode. For example, transistor Tr can be a TGSA transistor.

[0072] The liquid crystal element included in the display device can be of various structures. Typically, transmissive liquid crystal elements employing VA (Vertical Alignment), FFS (Fringe Field Switching), or IPS (In-Plane Switching) modes can be used. Furthermore, not only transmissive liquid crystal elements but also reflective or semi-transmissive liquid crystal elements can be used. Additionally, a normally black liquid crystal display device is preferred.

[0073] For example, as a VA mode, you can use MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, ASV (Advanced Super View) mode, etc.

[0074] Furthermore, various liquid crystal elements employing different modes can be used as liquid crystal elements. For example, in addition to VA mode, FFS mode, and IPS mode, liquid crystal elements in TN (Twisted Nematic), ASM (Axially Symmetric Aligned Micro-cell), OCB (Optically Compensated Birefringence), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroelectric Liquid Crystal), ECB (Electrically Controlled Birefringence), and guest-host modes can also be used.

[0075] Here, a liquid crystal display device is a display device that uses polarization and the optical modulation effect of liquid crystals to control the transmission or non-transmission of light. The optical modulation effect of liquid crystals is controlled by the electric field (horizontal, vertical, or tilted electric field) applied to the liquid crystal. Liquid crystals that can be used as liquid crystal elements include thermotropic liquid crystals, low-molecular-weight liquid crystals, high-molecular-weight liquid crystals, polymer-dispersed liquid crystals (PDLCs), polymer network liquid crystals (PNLCs), ferroelectric liquid crystals, and antiferroelectric liquid crystals. These liquid crystal materials exhibit cholesteric, smectic, cubic, chiral nematic, and homogeneous phases depending on the conditions. Furthermore, either positive or negative liquid crystals can be used as liquid crystal materials; the appropriate liquid crystal material can be selected based on the mode or design used.

[0076] [Example of pixel structure] The following describes a structural example of a pixel that can be used in the pixel section 101 described above.

[0077] <Structure Example 1> Figure 2A This is a top view of the pixel 70 of the display device 10. Note that some components (such as insulating layers) are omitted here.

[0078] Pixel 70 includes a sub-pixel 71R that emits red light, a sub-pixel 71G that emits green light, and a sub-pixel 71B that emits blue light.

[0079] The sub-pixel is connected to the conductive layer 23, which serves as a gate line, and the conductive layer 31, which serves as a source line. Each intersection of the conductive layer 23 and the conductive layer 31 is provided with a sub-pixel. The sub-pixel is provided with a transistor 51 and a conductive layer 32, which serves as a pixel electrode.

[0080] The conductive layer 32 is used as a pixel electrode of the liquid crystal element. In this case, the conductive layer 32 can be made of a conductive material that is transparent to visible light.

[0081] Note that when the light-emitting element is used as a display element, the conductive layer 32 is used as the pixel electrode of the light-emitting element. In the case of a top-emitting type light-emitting element, a conductive material that is reflective to visible light is used as the conductive layer 32. In the case of a bottom-emitting type light-emitting element, a conductive material that is transparent to visible light is used as the conductive layer 32. In the case of a double-sided emitting type light-emitting element, a conductive material that is both reflective and transparent to visible light is used as the conductive layer 32. Furthermore, when the light-emitting element is used as a display element, two or more transistors can be used for sub-pixels, wherein transistor 51 is used as a drive transistor to control the current flowing through the light-emitting element.

[0082] Figure 2B Showing the corresponding Figure 2A A cross-sectional schematic diagram of the cut-off line AB in the diagram. The display device 10 includes a transistor 51 and a conductive layer 32 on an insulating layer 11 on a substrate (not shown).

[0083] Transistor 51 includes a semiconductor layer 21, an insulating layer 22 in which a portion serves as a gate insulating layer, a conductive layer 23 in which a portion serves as a gate electrode, a conductive layer 24 in which a portion serves as one of a source electrode and a drain electrode, and a conductive layer 25 in which a portion serves as the other of a source electrode and a drain electrode. Transistor 51 is a TGSA transistor including a semiconductor layer 21 disposed on a plane and a gate electrode disposed thereon.

[0084] There are no restrictions on the semiconductor used for semiconductor layer 21, but oxide semiconductors are particularly preferred. Hereinafter, unless otherwise specified, the use of oxide semiconductors for semiconductor layer 21 will be described.

[0085] An insulating layer 11 has a conductive layer 31 disposed on it, and an insulating layer 41 is disposed on top of the conductive layer 31. A conductive layer 24 and a conductive layer 25 are disposed on the insulating layer 41. A semiconductor layer 21 is disposed on the conductive layer 24, the conductive layer 25, and the insulating layer 41. The semiconductor layer 21 is in contact with the top surfaces of the conductive layer 24 and the conductive layer 25. An insulating layer 22 is disposed on top of the semiconductor layer 21, the conductive layer 24, the conductive layer 25, and the insulating layer 41, and a conductive layer 23 overlapping the semiconductor layer 21 is disposed on the insulating layer 22. An insulating layer 42 is disposed on top of the insulating layer 22 and the conductive layer 23, and a conductive layer 32 is disposed on the insulating layer 42.

[0086] exist Figure 2A and Figure 2BIn the connecting portion 12 shown, the conductive layer 31 is connected to the conductive layer 24. Specifically, the conductive layer 31 contacts the conductive layer 24 within an opening provided in the insulating layer 41. Here, the semiconductor layer 21 extends into the connecting portion 12. As a result, the contact area between the semiconductor layer 21 and the conductive layer 24 can be increased, the contact resistance between them can be reduced, and thus the on-state current of the transistor 51 can be increased.

[0087] exist Figure 2A and Figure 2B In the connecting portion 13 shown, the conductive layer 25 is connected to the conductive layer 32. Specifically, the conductive layer 25 is in contact with the conductive layer 32 within the opening provided in the insulating layer 42.

[0088] <Structure Example 2> Figure 3A The display device 10a shown is an example that includes a conductive layer 33 and an insulating layer 43.

[0089] A conductive layer 33 is disposed on the insulating layer 42, and the insulating layer 43 is disposed such that it covers the conductive layer 33. The conductive layer 32 is disposed on the insulating layer 43. The conductive layer 32 contacts the conductive layer 25 within the openings disposed in the insulating layers 43, 42, and 22. The conductive layer 33 is preferably made of a light-transmitting conductive material.

[0090] <Structure Example 3> exist Figure 3B In the display device 10b shown, the portion of the insulating layer 22 other than the area near the region overlapping with the conductive layer 23 is removed. By positioning the end of the conductive layer 23 inside the end of the insulating layer 22, a high-resistivity LDD region can be formed in the semiconductor layer 21. Alternatively, the end of the insulating layer 22 can be aligned with the end of the conductive layer 23. Although a different photomask than the conductive layer 23 can be used to process the insulating layer 22, it is preferable to use the same photomask as the conductive layer 23 to simplify the process and reduce end misalignment. Furthermore, because the portion of the semiconductor layer 21 that does not overlap with the insulating layer 22 is in contact with the insulating layer 42, impurities such as hydrogen diffuse from the insulating layer 42 into this portion, causing it to become n-type, thus achieving low resistance. This increases the on-state current.

[0091] <Structure Example 4> Figure 3C and Figure 3D The display device 10c shown is an example where the end of the semiconductor layer 21 coincides with the ends of the conductive layer 24 and the conductive layer 25. The semiconductor layer 21 extends to the connection portion 13. This reduces the contact resistance between the semiconductor layer 21 and the conductive layer 25.

[0092] <Structure Example 5> Figure 4A and Figure 4B The semiconductor device 10d shown includes a region where conductive layers 23, 24, and 25 overlap. This increases the on-state current of the transistor 51.

[0093] <Structure Example 6> exist Figure 4C and Figure 4D In the display device 10e shown, the semiconductor layer 21 has a portion that contacts the side surface of the insulating layer 41 and the top surface of the insulating layer 11 within an opening provided in the insulating layer 41. This allows for an increase in channel length without increasing the footprint.

[0094] <Structure Example 7> Figure 5A The display device 10f shown is an example of display device 10e with an additional conductive layer 31a. The conductive layer 31a is located on the insulating layer 11 and is in contact with the bottom surface of the semiconductor layer 21. The channel length of the transistor 51 is twice the thickness of the insulating layer 41. Thus, a transistor with an extremely short channel length can be realized. In addition, the conductive layer 31a also serves as a light-shielding film to block light incident on the semiconductor layer 21 from below the insulating layer 11.

[0095] <Structure Example 8> Figure 5B and Figure 5C The display device 10g shown is an example where the conductive layers 24 and 25 are in contact with the top surface of the semiconductor layer 21. In this case, the semiconductor layer 21 preferably does not extend to the connection portion 12. As a result, since the semiconductor layer 21 is not sandwiched between the conductive layers 24 and 31, their contact resistance can be reduced.

[0096] <Structure Example 9> Figure 6A and Figure 6B The display device 10h shown is an example in which a conductive layer 31a is provided that overlaps with the semiconductor layer 21. The conductive layer 31a is used as a light-shielding film. Preferably, the conductive layer 31a is a conductive film obtained by processing the same conductive film as the conductive layer 31.

[0097] <Structure Example 10> Figure 6C and Figure 6D The display device 10i shown is an example of conductive layer 31a and conductive layer 23 being connected in the connection portion 14. Figure 6D The right side shows a cross-section of the connection portion 14 and its vicinity. The conductive layer 31a is used as the second gate (also called the back gate) of the transistor 51. This increases the on-state current of the transistor 51.

[0098] <Structure Example 11> Figure 7A The display device 10j shown is an example in which a conductive layer 24a is included between the conductive layer 31a and the conductive layer 23 in the connecting portion 14. The conductive layer 24a is formed by processing the same conductive film as the conductive layer 24 and the conductive layer 25.

[0099] <Structure Example 12> Figure 7B and Figure 7C The display device 10k shown is an example in which a conductive layer 34 is included in the connecting portion 12. The conductive layer 34 is disposed on the insulating layer 42, and is in contact with the top surface of the conductive layer 24 inside the openings provided in the insulating layer 42 and the insulating layer 22 in the connecting portion 12. Furthermore, an insulating layer 44 is disposed to cover the conductive layer 34 and the insulating layer 42, and a conductive layer 33 is disposed on the insulating layer 44. The conductive layer 33 is in contact with the top surface of the conductive layer 25 inside the openings provided in the insulating layers 43, 44, 42, and 22.

[0100] <Structure Example 13> Figure 8A and Figure 8B The display device 10l shown is an example in which a conductive layer 34a is included in the connection portion 13. The conductive layer 34a is formed by processing the same conductive film as the conductive layer 34. In the connection portion 13, the conductive layer 34a is disposed between the conductive layer 25 and the conductive layer 32.

[0101] <Structure Example 14> Figure 8C and Figure 8D The display device 10m shown is an example in which the semiconductor layer 21 extends to the connection portion 12 and the connection portion 13 in the display device 10l. In the connection portion 12 and the connection portion 13, an opening is provided in the semiconductor layer 21, the conductive layer 34 is in contact with the conductive layer 24, and the conductive layer 34a is in contact with the conductive layer 25.

[0102] <Structure Example 15> Figure 9A The display device 10n shown is an example where part of the conductive layer 34 also serves as the conductive layer 24, but does not include the connecting portion 12. Furthermore, although... Figure 9A An example with conductive layer 31a is shown, but conductive layer 31a may be omitted if not needed.

[0103] <Structure Example 16> Figure 9B The display device 10o shown is an example of a stacked structure using conductive layer 31 and conductive layer 34 as wiring for source lines. Conductive layer 31 and conductive layer 34 are connected by a connecting portion 12, etc. This reduces wiring resistance.

[0104] <Structure Example 17> Figure 9C The display device 10p shown is an example of a stacked structure using conductive layer 31 and conductive layer 34 as wiring for the source line, where conductive layer 34 does not overlap with conductive layer 23. Thus, by employing a structure in which neither conductive layer 31 nor conductive layer 34 is disposed at the intersection of the source line and the gate line, the parasitic capacitance between the source line and the gate line can be reduced.

[0105] <Structure Example 18> Figure 9D and Figure 9E The display device 10q shown is an example including a conductive layer 23b. The conductive layer 23b is disposed in the region where it overlaps with the conductive layer 25, separated by an insulating layer 22. A capacitor formed between the conductive layer 23b and the conductive layer 25 can be used as a storage capacitor. The conductive layer 23b is formed by processing the same conductive film as the conductive layer 23.

[0106] <Structure Example 19> Figure 10A and Figure 10B The display device 10r shown is an example in which a conductive layer 35 is used instead of a conductive layer 23b. A conductive film that is transparent to visible light is used as the conductive layer 35. Preferably, the conductive layer 25 is also a conductive film that is transparent to visible light. Thus, both the portion including the conductive layer 25 and the portion including the conductive layer 35 allow light to pass through, thereby increasing the pixel aperture ratio. Alternatively, a transparent conductive film can also be used for the conductive layer 24.

[0107] <Structure Example 20> Figure 11A The display device 10s shown is an example in which a conductive layer 31a is also provided in the display device 10r. In this case, the conductive layer 31a and the conductive layer 23 can also be connected by the connecting part 14 described above.

[0108] <Structure Example 21> Figure 11B The display device 10t shown is an example where a conductive layer 34 is used instead of the conductive layer 31 of the display device 10s. Furthermore, Figure 11B This shows an example of a case where conductive layer 34a is provided. Conductive layer 34a may be omitted if not needed.

[0109] <Structure Example 22> Figure 11C The display device 10u shown is an example where the conductive layer 23 does not include the protruding portion used as a gate electrode as included in the display device 10, etc. The conductive layer 23 has a linear (rectangular) shape. Furthermore, when viewed in a planar view, the conductive layer 24 and the conductive layer 25 sandwich the conductive layer 23.

[0110] <Structure Example 23> Figure 11D The display device 10v shown is an example of a case where a conductive layer 31a is provided in the display device 10u.

[0111] <Structure Example 24> Figure 11E The display device 10w shown is an example of the case where the semiconductor layer 21 extends to the connection portion 12 and the connection portion 13 in the display device 10u.

[0112] <Structure Example 25> Figure 12A The display device 10x shown is an example of a case where a conductive layer 31a is provided in the display device 10w.

[0113] <Structure Example 26> Figure 12B The display device 10y shown is an example in which the semiconductor layer 21 is disposed in a manner overlapping with the conductive layer 31. The channel formation region of the semiconductor layer 21 is located on the conductive layer 31. As a result, the area of ​​the light-shielding region can be reduced, thereby increasing the aperture ratio.

[0114] <Structure Example 27> Figure 12C The display device 10z shown is an example of a display device 10y in which the connecting portion 13 is provided in a manner that overlaps with the conductive layer 31. As a result, the aperture ratio can be further improved.

[0115] <Structure Example 28> Figure 12D The display device 10aa shown is an example of a display device 10u in which a conductive layer 34 is used instead of a conductive layer 31.

[0116] <Structure Example 29> Figure 12E The display device 10ab shown is an example of a case where a conductive layer 31a is provided in the display device 10aa.

[0117] <Structure Example 30> Figure 13A The display device 10ac shown is an example of a case where a conductive layer 34a is provided in the display device 10ab.

[0118] <Structure Example 31> Figure 13B The display device 10ad shown is an example in which the semiconductor layer 21 is disposed in a manner that overlaps with the intersection of the conductive layer 34 and the conductive layer 23.

[0119] <Structure Example 32> Figure 13C The display device 10ae shown is an example of a case where a conductive layer 31a is provided in the display device 10ad.

[0120] <Structure Example 33> Figure 13D The display device 10af shown is an example of a case where a conductive layer 34a is provided in the display device 10ae.

[0121] <Structure Example 34> Figure 14A The display device 10ag shown illustrates a vertical transistor 52.

[0122] Transistor 52 includes a semiconductor layer 21a, an insulating layer 22 in which a portion serves as a gate insulating layer, a conductive layer 23c in which a portion serves as a gate electrode, a conductive layer 31 in which a portion serves as one of a source electrode and a drain electrode, and a conductive layer 24b in which a portion serves as the other of a source electrode and a drain electrode.

[0123] An insulating layer 41 is disposed on the conductive layer 31, and a conductive layer 24b is disposed on the insulating layer 41. Openings extending to the conductive layer 31 are provided in both the conductive layer 24b and the insulating layer 41. The semiconductor layer 21a has a portion that contacts the conductive layer 24b, a portion that contacts the side of the insulating layer 41 within the opening, and a portion that contacts the conductive layer 31 at the bottom of the opening. The insulating layer 22 is disposed within the opening to cover the semiconductor layer 21a, and the conductive layer 23c is disposed within the opening to cover the insulating layer 22.

[0124] Semiconductor layer 21a is formed by processing the same conductive film as semiconductor layer 21. Conductive layer 24b is formed by processing the same conductive film as conductive layers 24 and 25. Conductive layer 23c is formed by processing the same conductive film as conductive layer 23. Thus, transistor 52 can be manufactured in the same process as the elements constituting transistor 51, enabling a display device with two types of transistors to be mixed and installed at low cost.

[0125] The channel length of transistor 52 is approximately the same as the thickness of insulating layer 41, so a transistor with an extremely short channel length can be formed. Therefore, transistor 52 can be a transistor with a large on-state current. Transistor 52 can be disposed in source line drive circuit section 102, gate line drive circuit section 103, protection circuit section 104, and touch sensor drive circuit section 105, etc.

[0126] <Structure Example 35> Figure 14BThe display device 10ah shown is an example where the portion of the insulating layer 22, except for the area near the region where it overlaps with the conductive layers 23 and 23c, is removed. Transistor 51 is provided with the insulating layer 22, and transistor 52 is provided with the insulating layer 22a.

[0127] <Structure Example 36> Figure 14C The display device 10ai shown is an example including a connection portion of conductive layer 24b and conductive layer 23. Conductive layer 23 contacts conductive layer 24b inside an opening provided in insulating layer 22. Furthermore, transistor 52 includes a conductive layer 31c separate from conductive layer 31. For example, transistor 52 can be used as a transistor constituting gate line drive circuit section 103.

[0128] <Structure Example 37> Figure 14D The display device 10aj shown is an example where conductive layer 24b and conductive layer 23 are connected via conductive layer 32a. Conductive layer 32a and conductive layer 24b are connected inside openings provided in insulating layer 42 and insulating layer 22. Conductive layer 32a and conductive layer 23 are connected inside openings provided in insulating layer 42. Conductive layer 32a is formed by processing the same conductive film as conductive layer 32.

[0129] <Structure Example 38> Figure 14E The display device 10ak shown is an example where conductive layer 24b and conductive layer 23 are connected via conductive layer 34b. Conductive layer 34b and conductive layer 24b are connected inside openings provided in insulating layer 42 and insulating layer 22. Conductive layer 34b and conductive layer 23 are connected inside openings provided in insulating layer 42. Conductive layer 34b is formed by processing the same conductive film as conductive layer 34 (not shown).

[0130] <Structure Example 39> Figure 15A The display device 10a1 shown is an example where the conductive layer 24b is connected to the conductive layer 24 via the conductive layer 34b. In this case, the conductive layer 34b is used as a source line. For example, the transistor 52 can be used as a transistor constituting the source line drive circuit section 102.

[0131] <Structure Example 40> Figure 15B The display device 10am shown illustrates a transistor 53 using polysilicon. In this context, transistor 53 can be referred to as an LTPS transistor.

[0132] Transistor 53 includes a semiconductor layer 61, an insulating layer 62 in which a portion serves as a gate insulating layer, a conductive layer 63 in which a portion serves as a gate electrode, a conductive layer 64 in which a portion serves as one of a source electrode and a drain electrode, and a conductive layer 65 in which a portion serves as the other of a source electrode and a drain electrode. The semiconductor layer 61 is made of crystalline silicon, preferably polycrystalline silicon.

[0133] A semiconductor layer 61 is disposed on the insulating layer 11, and an insulating layer 62 is disposed to cover both the semiconductor layer 61 and the insulating layer 11. A conductive layer 63, overlapping the semiconductor layer 61, is disposed on the insulating layer 62, and an insulating layer 45 is disposed to cover both the conductive layer 63 and the insulating layer 62. A conductive layer 64 and a conductive layer 65 are disposed on the insulating layer 45. Both the conductive layer 64 and the conductive layer 65 are connected to the semiconductor layer 61 inside openings disposed in the insulating layers 45 and 62, respectively. Furthermore, transistors 51 and 52 are disposed on the insulating layer 46.

[0134] Figure 15B The diagram shows conductive layer 63a, formed by processing the same conductive film as conductive layer 63, and conductive layer 64a, formed by processing the same conductive film as conductive layers 64 and 65. Also shown are conductive layers 31d and 31e, formed on insulating layer 46 by processing the same conductive film as conductive layer 31. Conductive layer 31d contacts the top surface of conductive layer 64a through an opening in insulating layer 46. Conductive layer 31e contacts the top surface of conductive layer 63a through openings in insulating layers 46 and 45.

[0135] Because the on-state current of transistor 53 can be increased, transistor 53 can be placed in the source line drive circuit section 102, the gate line drive circuit section 103, the protection circuit section 104, and the touch sensor drive circuit section 105, etc. Furthermore, transistor 53 can be used as a transistor constituting a pixel circuit.

[0136] <Structure Example 41> Figure 15C The example shown is a case where the conductive layer 64 and conductive layer 65 are formed by processing the same conductive film as the conductive layer 31. Figure 15C The connection between conductive layer 63a and conductive layer 31e is also shown. Furthermore, transistors 51 and 52 are disposed on insulating layer 45. This structure simplifies the manufacturing process, thereby reducing manufacturing costs.

[0137] <Structure Example 42> Figure 15D The display device 10ao shown is an example in which conductive layers 64 and 65 are formed by processing the same conductive film as conductive layers 24 and 25. Figure 15D The connection between conductive layer 63a and conductive layer 24d is also shown.

[0138] <Structure Example 43> Figure 16A The example shown is a case where the conductive layer 64 and conductive layer 65 are formed by processing the same conductive film as the conductive layer 23. Figure 16A The connection between conductive layer 63a and conductive layer 23d is also shown.

[0139] <Structure Example 44> Figure 16B The display device 10aq shown illustrates an example where conductive layer 63 is formed by processing the same conductive film as conductive layer 31, and conductive layers 64 and 65 are formed by processing the same conductive film as conductive layers 24 and 25. Figure 16B The connection between conductive layer 31f and conductive layer 24d is also shown. Furthermore, transistors 51 and 52 are disposed on insulating layer 62.

[0140] <Structure Example 45> Figure 16C The example shown is that the conductive layer 63 is formed by processing the same conductive film as the conductive layer 31, and the conductive layers 64 and 65 are formed by processing the same conductive film as the conductive layer 23. Figure 16B The connection between conductive layer 31f and conductive layer 23d is also shown.

[0141] The above is an explanation of the structural examples.

[0142] [Regarding the constituent elements] <Substrate> As a substrate for forming transistors, an insulating substrate, a semiconductor substrate, or a conductive substrate can be used, for example. Examples of insulating substrates include glass substrates, quartz substrates, sapphire substrates, stabilized zirconium oxide substrates (yttrium-stabilized zirconium oxide substrates, etc.), and resin substrates. Examples of semiconductor substrates include semiconductor substrates made of silicon or germanium, or compound semiconductor substrates composed of silicon carbide, silicon-germanium, gallium arsenide, indium phosphide, zinc oxide, gallium oxide, and gallium nitride. Furthermore, semiconductor substrates having insulating regions within the aforementioned semiconductor substrates, such as SOI (Silicon-on-Insulator) substrates, can also be used. Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, and conductive resin substrates. Alternatively, substrates containing metal nitrides or metal oxides can also be used. Furthermore, substrates with conductive or semiconductor layers disposed on insulating substrates, substrates with conductive or insulating layers disposed on semiconductor substrates, and substrates with semiconductor or insulating layers disposed on conductive substrates can also be used. Alternatively, substrates with components disposed on the aforementioned substrates can also be used. Examples of components mounted on a substrate include capacitors, resistors, switching elements (including transistors), light-emitting elements, and memory elements.

[0143] <Semiconductor layer> Semiconductor layer 21 preferably comprises metal oxide (oxide semiconductor).

[0144] Examples of metal oxides that can be used in semiconductor layer 21 include In oxide, Ga oxide, and Zn oxide. The metal oxide preferably contains at least In, Zn, Sn, or Al, and more preferably In or Zn.

[0145] Furthermore, the metal oxide preferably contains two or three elements selected from In, element M, and Zn. For example, In-M-Zn oxide, In-Zn oxide, In-M oxide, or M-Zn oxide can be used. Note that element M is a metallic element or half-metallic element with a high bond energy with oxygen, such as a metallic element or half-metallic element with a higher bond energy with oxygen than indium. Examples of element M include Al, Ga, Sn, Y, Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Mo, Hf, Ta, W, La, Ce, Nd, Mg, Ca, Sr, Ba, B, Si, Ge, and Sb. The metal oxide preferably contains one or more of the above elements, and particularly preferably contains one or more elements selected from Al, Ga, Y, and Sn. Here, in this specification, etc., "metallic element" sometimes includes half-metallic elements.

[0146] The atomic ratio of In in In-M-Zn oxides is preferably greater than or equal to the atomic ratio of M. Increasing the atomic ratio of indium in the metal oxide can improve the on-state current or field-effect mobility of transistors. Examples of suitable atomic ratios for the metal elements in In-M-Zn oxides include In:M:Zn ratios of 1:1:1, 1:1:1.2, 2:1:3, 3:1:2, 4:2:3, 4:2:4.1, 5:1:3, and 5:1:6, as well as compositions close to these ratios. Furthermore, compositions close to these ratios include those within ±30% of the desired atomic ratio.

[0147] In In-M-Zn oxides, the atomic ratio of In can also be less than that of M. By increasing the atomic ratio of M in the metal oxide, the formation of oxygen vacancies can be suppressed. For example, examples of In:M:Zn atomic ratios of 1:3:2, 1:3:3, and 1:3:4, as well as compositions with ratios close to these, can be cited as In-M:Zn oxides.

[0148] The semiconductor layer 21 can be made of, for example, In oxide, In-Zn oxide, In-Ga oxide, In-Sn oxide, In-Ti oxide, In-W oxide, In-Ga-Al oxide, In-Ga-Sn oxide, In-Ga-Zn oxide, In-Sn-Zn oxide, In-Al-Zn oxide, In-Ti-Zn oxide, In-W-Zn oxide, In-Ga-Sn-Zn oxide, In-Ga-Al-Zn oxide, etc. Furthermore, as oxides that do not contain In, Ga oxide, Zn oxide, Ga-Zn oxide, Ga-Sn oxide, Al-Zn oxide, Al-Sn oxide, etc., can also be used. Using a Zn-free material such as indium oxide improves the affinity with the LSI manufacturing process, and is therefore preferred. On the other hand, using a Zn-containing material easily improves crystallinity, and is therefore preferred.

[0149] In addition, metal oxides can replace indium or contain metal elements with larger atomic numbers other than indium. Since the greater the overlap of the orbitals of the metal element, the greater the carrier conduction in the metal oxide, the field-effect mobility of the transistor can sometimes be improved when the metal oxide contains metal elements with large atomic numbers. For example, one or more metal elements belonging to the 5th period and the 6th period can be used. Specifically, examples include Y, Zr, Ag, Cd, Sn, Sb, Ba, Pb, Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, etc.

[0150] In addition, metal oxides can also contain one or more non-metallic elements. The inclusion of non-metallic elements in metal oxides can sometimes improve the field-effect mobility of transistors. Examples include C, N, P, S, Se, F, Cl, Br, and H.

[0151] Metal oxides can be formed appropriately using sputtering or ALD methods. Sputtering is preferred because it reduces impurity concentration. Furthermore, ALD offers excellent coverage, making it a preferred method. Note that when metal oxides are formed using sputtering, the composition of the deposited metal oxide sometimes differs from that of the target material. In particular, the zinc content in the deposited metal oxide can sometimes decrease to about 50% of the zinc content in the target material.

[0152] In this specification, the content of a certain metal element in a metal oxide refers to the proportion of the number of atoms of that element relative to the total number of atoms of the metal element contained in the metal oxide. For example, in a metal oxide containing metal elements X, Y, and Z, the number of atoms of each of metal elements X, Y, and Z contained in the metal oxide is A. X A Y A Z When the content of metallic element X is such that it can be expressed as A, the percentage of X in the composition of metal can be expressed as A. X / (A X +A Y +A Z Furthermore, when the ratio of the number of atoms of metal elements X, Y, and Z in a metal oxide (atomic ratio) is expressed as B... X B Y B Z When the content of metallic element X is such that B is used, the percentage of X can be expressed as B. X / (B) X +B Y +B Z ).

[0153] For example, when using metal oxides containing In, transistors with high on-state current can be achieved by increasing the In content.

[0154] By using a metal oxide that does not contain Ga or has a low Ga content in the semiconductor layer 21, a transistor with high reliability under forward bias can be realized. That is, a transistor with small fluctuations in the threshold voltage during PBTS (Positive Bias Temperature Stress) testing can be achieved. Furthermore, when using a Ga-containing metal oxide, the Ga content is preferably lower than the In content. Thus, a transistor with both high mobility and high reliability can be realized.

[0155] On the other hand, by increasing the Ga content, transistors with high reliability for light can be achieved. In other words, transistors with small threshold voltage variations during NBTIS (Negative Bias Temperature Illumination Stress) testing can be realized. Specifically, metal oxides with a higher Ga atomic number than those with a higher In atomic number have larger band gaps, which can reduce the threshold voltage variation during NBTIS testing of the transistor.

[0156] Furthermore, increasing the zinc content can enhance the crystallinity of metal oxides, thereby suppressing the diffusion of impurities within them. This, in turn, suppresses variations in the electrical characteristics of the transistor, thus improving reliability.

[0157] Semiconductor layer 21 may also have a stacked structure comprising two or more metal oxides. The compositions of the two or more metal oxides included in semiconductor layer 21 may be the same or substantially the same. When using a stacked structure of metal oxides with the same composition, for example, the same sputtering target can be used, thereby reducing manufacturing costs. Note that a stacked structure of two or more metal oxides with different compositions can also be used. Furthermore, by utilizing the ALD method, metal oxides whose composition continuously varies in the thickness direction can be formed. Therefore, compared to using a film with a predetermined composition, not only can the range of design choices be expanded, but the formation of interface states between two layers with different compositions can also be prevented, thus improving the electrical characteristics and reliability of the transistor.

[0158] In the case where semiconductor layer 21 has a two-layer structure, the second layer, i.e., the side closer to the gate electrode, preferably uses a material with higher mobility (higher conductivity) than the first layer. This allows for the realization of a transistor that is normally off and has a large on-state current. Therefore, both low power consumption and high performance can be achieved simultaneously. Alternatively, a material with higher mobility than the second layer can be used in the first layer, i.e., the side in contact with the source and drain electrodes. This reduces the contact resistance between semiconductor layer 21 and the source and drain electrodes, thereby reducing parasitic resistance and enabling the realization of a transistor with a large on-state current.

[0159] Furthermore, when semiconductor layer 21 has a three-layer structure, the second layer preferably uses a material with higher mobility compared to the first and third layers. This allows for the realization of transistors with high on-state current and high reliability.

[0160] When the semiconductor layer 21 has a stacked structure, all layers can be deposited using the same deposition method, or different deposition methods can be combined. For example, sputtering and ALD methods can be combined to form the semiconductor layer 21 with a stacked structure. Here, in deposition methods such as sputtering, a mixed layer (also called mixing) is sometimes formed at the interface between the semiconductor layer and the surface to be formed. Therefore, by using ALD to deposit the first layer to suppress mixing and using sputtering to deposit the second layer to deposit a highly crystalline film, a transistor with both high reliability and high electrical characteristics can be realized. Furthermore, a three-layer structure using ALD to deposit the third layer can also be used. In addition, it is preferable to perform heat treatment after depositing the stacked film using a combination of ALD and sputtering methods. As a result, crystal growth sometimes occurs from the sputtered layer to the ALD-deposited layer, thereby forming a highly crystalline semiconductor layer as the entire stacked film.

[0161] Furthermore, when the semiconductor layer 21 has a stacked structure, a high-mobility material can be used in the layer on the side in contact with the source and drain electrodes. This reduces the contact resistance between the semiconductor layer 21 and the source and drain electrodes, enabling the realization of transistors with high on-state current. In particular, in bottom contact structures (structures where semiconductor layers are disposed on the source and drain electrodes), the aforementioned contact resistance is sometimes higher than in top contact structures (structures where source and drain electrodes are disposed on the semiconductor layer). Therefore, it is preferable to use a high-mobility material in the layer on the side in contact with the source and drain electrodes.

[0162] The higher the content of elements such as indium that contribute to improved conductivity, the higher the mobility and conductivity. Examples of materials with high mobility include those with atomic ratios close to In:Ga:Zn ratios of 4:3:2, 1:1, 2:1, 4:1, 40:1:10, 20:1:10, 95:5, and 90:10. Conversely, materials with lower mobility than these examples include those with In:Ga:Zn ratios of 1:3:2, 1:3:4, 2:2:1, 1:1:1, and 1:1:2.

[0163] A crystalline metal oxide layer is preferably used as the semiconductor layer 21. For example, a metal oxide layer having a CAAC (C-Axis Aligned Crystal) structure, a polycrystalline structure, a nano-crystal (nc: nano-crystal) structure, etc., can be used. By using a crystalline metal oxide layer as the semiconductor layer 21, the defect state density in the semiconductor layer 21 can be reduced, thereby enabling a highly reliable semiconductor device.

[0164] The higher the crystallinity of the metal oxide layer used for semiconductor layer 21, the lower the defect state density in semiconductor layer 21 can be. On the other hand, by using a metal oxide layer with low crystallinity, transistors capable of carrying large currents can be realized.

[0165] Compared to transistors using amorphous silicon, transistors using oxide semiconductors (hereinafter referred to as OS transistors) have a very high field-effect mobility. Furthermore, OS transistors exhibit extremely low source-drain leakage current (hereinafter referred to as off-state current) in the off-state, allowing them to retain the charge stored in the capacitor connected in series with the transistor for extended periods. In addition, the use of OS transistors can reduce the power consumption of semiconductor devices.

[0166] One aspect of the semiconductor device of the present invention can be applied, for example, to a display device. When increasing the luminous brightness of a light-emitting device included in the pixel circuit of a display device, it is necessary to increase the current flowing through the light-emitting device. For this purpose, it is necessary to increase the source-drain voltage of the driving transistor included in the pixel circuit. Because the source-drain breakdown voltage of an OS transistor is higher than that of a silicon transistor (hereinafter referred to as a Si transistor), a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the driving transistor included in the pixel circuit, the current flowing through the light-emitting device can be increased, thereby improving the luminous brightness of the light-emitting device.

[0167] When operating in the saturation region, OS transistors, compared to Si transistors, allow for smaller changes in source-drain current in response to variations in the gate-source voltage. Therefore, by using OS transistors as driving transistors within pixel circuits, the amount of current flowing through the light-emitting device can be precisely controlled. This, in turn, increases the grayscale of the pixel circuit. Furthermore, a stable current can flow even when variations in the electrical characteristics (e.g., resistance) or non-uniformity of the light-emitting device occur.

[0168] As described above, by using OS transistors as the driving transistors included in the pixel circuit, the following effects can be achieved: "suppression of black blur", "increase in luminous brightness", "multi-grayscale conversion", "suppression of the effects of uneven manufacturing of light-emitting devices", etc.

[0169] OS transistors exhibit minimal changes in electrical characteristics due to radiation exposure, meaning they possess high radiation tolerance and can therefore be appropriately used in environments where radiation is likely to occur. OS transistors can also be described as having high reliability against radiation. For example, OS transistors can be appropriately used in the pixel circuitry of X-ray flat panel detectors. Furthermore, OS transistors can be appropriately used in semiconductor devices used in outer space. Examples of radiation include electromagnetic radiation (e.g., X-rays and gamma rays) and particle radiation (e.g., alpha rays, beta rays, proton radiation, and neutron radiation).

[0170] Note that the semiconductor material that can be used in semiconductor layer 21 is not limited to oxide semiconductors. For example, semiconductors composed of a single element or compound semiconductors can be used. Examples of semiconductors composed of a single element include Si (including single crystal, polycrystalline, microcrystalline, and amorphous) or Ge. Examples of compound semiconductors include GaAs and SiGe. Examples of compound semiconductors include organic semiconductors, nitride semiconductors, or oxide semiconductors. These semiconductor materials may also contain impurities as dopants.

[0171] Alternatively, semiconductor layer 21 can also be made of a material with a layered crystalline structure. Materials with a layered crystalline structure exhibit high conductivity within their layers. Therefore, by using such a material with a layered crystalline structure in the channel formation region, a transistor with a large on-state current can be provided. Examples include graphene, silicene, and chalcogenides. Chalcogenides can be derived from transition elements such as Mo, W, Hf, or Zr. In this case, group 16 elements such as S, Se, and Te can be used as chalcogen elements.

[0172] There are no particular restrictions on the crystallinity of the semiconductor material used for semiconductor layer 21; amorphous semiconductors, single-crystal semiconductors, or semiconductors with crystallinity other than single crystals (polycrystalline semiconductors, microcrystalline semiconductors, or semiconductors with a portion of them having crystalline regions) can be used. Using a crystalline semiconductor can suppress the degradation of transistor characteristics, and is therefore preferred.

[0173] <Gate insulating layer> The insulating layer 22 is used as a gate insulating layer for a transistor, and can also be used as a dielectric layer for a capacitor. When an oxide semiconductor is used for the semiconductor layer 21, an oxide insulating film is preferably used as the film in the insulating layer 22 that is at least in contact with the semiconductor layer 21. For example, one or more of silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, hafnium oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, and Ga-Zn oxide can be used as the insulating layer 22. In addition, nitride insulating films such as silicon nitride, silicon oxynitride, aluminum nitride, and aluminum oxynitride can also be used as the insulating layer 22. Furthermore, the insulating layer 22 can also have a stacked structure, for example, it can have a stacked structure including one or more oxide insulating films and one or more nitride insulating films.

[0174] In this specification, etc., oxynitrides refer to materials with an oxygen content greater than a nitrogen content. Nitrogen oxides refer to materials with a nitrogen content greater than a oxygen content.

[0175] Furthermore, as the insulating layer 22, it is preferable to use an insulating material made of a high-k material, and more preferably, a laminated structure of a high-k material with a high relative permittivity and a material with a dielectric strength greater than that high-k material. For example, as the insulating layer 22, an insulating film (also known as ZAZ) sequentially laminated with zirconium oxide, alumina, and zirconium oxide can be used. Alternatively, for example, an insulating film (also known as ZAZA) sequentially laminated with zirconium oxide, alumina, zirconium oxide, and alumina can be used. Furthermore, for example, an insulating film sequentially laminated with hafnium zirconium oxide, alumina, hafnium zirconium oxide, and alumina can be used. By using an insulator with high insulation resistance, such as alumina, the insulation resistance can be improved to suppress electrostatic discharge damage to the capacitor.

[0176] Furthermore, ferroelectric materials can also be used as the insulating layer 22. Examples of ferroelectric materials include hafnium oxide, zirconium oxide, and HfZrO. X Metal oxides (where X is a real number greater than 0).

[0177] <Conductive Layer> Conductive layers 24 and 25 are in contact with the semiconductor layer 21. Here, when an oxide semiconductor is used as the semiconductor layer 21, for example, if an easily oxidized metal such as aluminum is used for the portion of conductive layer 24 or conductive layer 25 that contacts the semiconductor layer 21, there is a concern that an insulating oxide (e.g., aluminum oxide) may form between the conductive layer 24 or conductive layer 25 and the semiconductor layer 21, hindering conduction between them. Therefore, it is preferable to use a conductive material that is not easily oxidized, a conductive material that maintains low resistance even if oxidized, or an oxide conductive material for at least the portion of conductive layer 24 or conductive layer 25 that contacts the semiconductor layer 21.

[0178] For example, titanium, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel, etc., are preferably used as conductive layers 24 or 25. The above materials are conductive materials that are not easily oxidized or that maintain conductivity even if oxidized, so they are preferred.

[0179] Alternatively, conductive oxides such as indium oxide, zinc oxide, In-Sn oxide, In-Zn oxide, In-W oxide, In-W-Zn oxide, In-Ti oxide, In-Ti-Sn oxide, In-Sn-Si oxide, and Ga-Zn oxide can be used. In particular, conductive oxides containing indium have high conductivity and are therefore preferred. Alternatively, the aforementioned oxide materials such as In-Ga-Zn oxide that can be used in semiconductor layer 21 can also be used as a conductive layer by increasing the carrier concentration.

[0180] For example, conductive layer 24 or conductive layer 25 can be a single-layer structure of the conductive oxide film described above, a three-layer structure in which a titanium nitride film, a tungsten film, and a titanium nitride film are stacked sequentially, a two-layer structure in which a ruthenium film or a ruthenium oxide film is stacked on a tungsten film, a two-layer structure in which a ruthenium film or a ruthenium oxide film is stacked on the conductive oxide film, or a two-layer structure in which the conductive oxide film is stacked on a ruthenium film or a ruthenium oxide film, etc. Note that ruthenium is a material that is not easily etched, so the thinner the material, the better. For example, it is preferable to use ruthenium with a thickness of 0.1 nm or more and 2 nm or less.

[0181] The conductive layer 23 is used as the gate electrode, and various conductive materials can be used. For example, a metal element selected from Al, Cr, Cu, Ag, Pt, Ta, Ni, Ti, Mo, W, Hf, V, Nb, Mn, Mg, Zr, Be, In, Ru, Ir, Sr, La, etc., or an alloy containing that metal element, is preferably used as the conductive layer 23. Alternatively, nitrides or oxides of the aforementioned metals or alloys can be used. For example, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel, etc., are preferred. Furthermore, semiconductors with high conductivity, such as polycrystalline silicon containing impurity elements like phosphorus, and silicides such as nickel silicides can also be used.

[0182] Alternatively, the conductive layer 23 may also use the nitrides and oxides that are applicable to the conductive layers 24 and 25 as described above.

[0183] Conductive layers 23, 24, and 25 are also used for wiring, and therefore preferably are laminated with low-resistance conductive materials. For example, the lower layer of conductive layers 24 and 25 may also use the low-resistance conductive material that can be used in conductive layer 23.

[0184] Conductive layers 31, 34, 63, 64 and 65 can also be made of low-resistance conductive materials that can be used in conductive layer 23.

[0185] Conductive layers 32, 33, and 35 can be made of conductive films that are transparent to visible light. For example, the conductive oxides described above that can be used in conductive layers 24 and 25 can be used.

[0186] <Insulating layer> Insulating layers 41, 42, 43, 44, 45, and 46 can all be used as interlayer insulating films. For example, they are preferably formed using deposition methods such as sputtering or plasma CVD. In particular, when using sputtering, hydrogen gas is not required as the deposition gas, thereby achieving a film with extremely low hydrogen content. This suppresses the supply of hydrogen to semiconductor layer 21, thus stabilizing the electrical characteristics of the transistor.

[0187] Since the insulating layer 41 contacts the channel formation region of the semiconductor layer 21, an oxide insulating film is preferably used. In particular, an oxide insulating film that releases oxygen upon heating is preferred. As the insulating layer 41, the oxide insulating film described above, which can be used as a gate insulating layer, can be used.

[0188] Furthermore, as the film used as an interlayer insulating layer, a deposition method that can be used to deposit the film at a higher deposition rate than other insulating layers is preferred. For example, as the insulating layer 41, a silicon oxide film can also be used, which is formed by using TEOS (Tetra-Ethyl-Ortho-Silicate, chemical formula: Si(OC2H5)4) and employing a plasma CVD method. This can improve the production rate.

[0189] Insulating layer 11 is used as a base insulating layer or an interlayer insulating layer. As insulating layer 11, it is preferable to use the insulating material described above that can be used in insulating layer 41, or an insulating material that is resistant to oxygen or hydrogen. For example, silicon nitride, silicon oxynitride, or aluminum oxide are preferred.

[0190] The above is an explanation of the constituent elements.

[0191] [Example of pixel circuit structure] One aspect of the present invention can be applied not only to display devices that use liquid crystal elements as display elements, but also to display devices that use light-emitting elements as display elements. Hereinafter, an example of the pixel circuit structure when using a light-emitting element as a display element will be described.

[0192] Figure 17AThe pixel circuit shown includes transistors M1 to M6, capacitors C1 and C2, and a light-emitting element EL. The pixel circuit is connected to wirings G1 to G3 used as gate lines, wiring D1 used as source lines, and wirings V1 to V3 supplied with a fixed potential.

[0193] In transistor M1, the gate is connected to wiring G1, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one of the source and drain of transistor M3, one electrode of capacitor C1, and the gate of transistor M2. In transistor M2, the back gate is connected to the other of the source and drain of transistor M4 and one electrode of capacitor C2, one of the source and drain is connected to wiring V2, and the other of the source and drain is connected to the other of the source and drain of transistor M3, the other electrode of capacitor C1, the other electrode of capacitor C2, one of the source and drain of transistor M6, and one of the source and drain of transistor M5. The gate of transistor M3 is connected to wiring G2. In transistor M4, the gate is connected to wiring G2, and one of the source and drain is connected to wiring V3. In transistor M5, the gate is connected to wiring G3, and the other of the source and drain is connected to one electrode of the light-emitting element EL. In transistor M6, the gate is connected to wiring G1, and the other of the source and drain is connected to wiring V1.

[0194] Transistor M2 is used as the driver transistor, and the other transistors are used as switches. Transistor M2 is preferably a TGSA transistor. Transistors M1, M4, and M6, which have a significant impact on the noise generated by capacitors C1 and C2, are preferably TGSA transistors or LTPS transistors with low parasitic capacitance. Additionally, transistors M3 and M5 are preferably vertical transistors with high on-state current.

[0195] Figure 17B The pixel circuit shown includes transistors M1 and M2, capacitors C1 and C2, and a light-emitting element EL. The pixel circuit is connected to wiring G1, which serves as a gate line, wiring D1, which serves as a source line, and wirings V1 and V2, which are supplied with a fixed potential.

[0196] In transistor M1, the gate is connected to wiring G1, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one electrode of capacitor C1 and the gate of transistor M2. In transistor M2, one of the source and drain is connected to the other electrode of capacitor C1, one electrode of capacitor C2, and one electrode of the light-emitting element EL, and the other of the source and drain is connected to wiring V1. The other electrode of capacitor C2 is connected to wiring V2.

[0197] Transistor M2 is used as the driver transistor, and the other transistors are used as switches. Transistor M2 is preferably a TGSA transistor. Transistor M1, which has a significant impact on the noise generated by capacitors C1 and C2, is preferably a TGSA transistor or an LTPS transistor with low parasitic capacitance.

[0198] Figure 17C The pixel circuit shown includes transistors M1 to M4, capacitors C1 and C2, and a light-emitting element EL. The pixel circuit is connected to wirings G1 to G3 used as gate lines, wiring D1 used as source lines, and wirings V1 and V2 supplied with a fixed potential.

[0199] In transistor M1, the gate is connected to wiring G3, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one electrode of capacitor C1 and the gate of transistor M2. In transistor M2, one of the source and drain and the back gate are connected to the other electrode of capacitor C1, one electrode of capacitor C2, one of the source and drain of transistor M3, and one electrode of the light-emitting element EL. The other of the source and drain is connected to one of the source and drain of transistor M4. In transistor M3, the gate is connected to wiring G1, and the other of the source and drain is connected to wiring V2. In transistor M4, the gate is connected to wiring G2, and the other of the source and drain is connected to wiring V1. The other electrode of capacitor C2 is connected to wiring V1.

[0200] Transistor M2 is used as the driver transistor, and the other transistors are used as switches. Transistor M2 is preferably a TGSA transistor. Transistor M1, which has a significant impact on the noise generated by capacitors C1 and C2, is preferably a TGSA transistor or an LTPS transistor with low parasitic capacitance. Furthermore, transistors M3 and M4 are preferably vertical transistors with high on-state current.

[0201] Figure 17D The pixel circuit shown includes transistors M1 to M6, capacitors C1 and C2, and a light-emitting element EL. The pixel circuit is connected to wirings G1 to G4 used as gate lines, wiring D1 used as source lines, and wirings V1 and V2 supplied with a fixed potential.

[0202] In transistor M1, the gate is connected to wiring G1, one of the source and drain is connected to wiring V1, and the other of the source and drain is connected to one of the source and drain of transistor M3 and one of the source and drain of transistor M2. In transistor M2, the gate and back gate are connected to wiring G2 and the gate of transistor M6, and the other of the source and drain is connected to one electrode of capacitor C1 and the gate of transistor M3. In transistor M3, the back gate and the other of the source and drain are connected to the other of the source and drain of transistor M4 and one of the source and drain of transistor M5. In transistor M4, the gate and back gate are connected to wiring G4 and the other electrode of capacitor C2, and the other of the source and drain is connected to wiring D1. In transistor M5, the gate is connected to wiring G3, and the other of the source and drain is connected to one electrode of the light-emitting element EL, the other electrode of capacitor C1, one electrode of capacitor C2, and one of the source and drain of transistor M6. The other of the source and drain of transistor M6 is connected to wiring V2.

[0203] Transistor M3 is used as the driver transistor, and the other transistors are used as switches. Transistor M3 is preferably a TGSA transistor. Transistor M2, which has a significant impact on the noise generated by capacitors C1 and C2, is preferably a TGSA transistor or an LTPS transistor with low parasitic capacitance. Furthermore, transistors M1, M4, M5, and M6 are preferably vertical transistors with high on-state current.

[0204] Figure 18A The pixel circuit shown includes transistors M1 to M4, capacitor C1, and light-emitting element EL. The pixel circuit is connected to wirings G1 to G3 used as gate lines, wiring D1 used as source lines, and wirings V1 to V3 supplied with a fixed potential.

[0205] In transistor M1, the gate is connected to wiring G1, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to the gate of transistor M2, one electrode of capacitor C1, and the other of the source and drain of transistor M3. In transistor M2, one of the source and drain is connected to wiring V2, and the other of the source and drain is connected to the other electrode of capacitor C1, one electrode of the light-emitting element EL, and one of the source and drain of transistor M4. In transistor M3, the gate is connected to wiring G2, and one of the source and drain is connected to wiring V1. In transistor M4, the gate is connected to wiring G3, and the other of the source and drain is connected to wiring V3.

[0206] Transistor M2 is used as the driver transistor, and the other transistors are used as switches. Transistor M2 is preferably a TGSA transistor. Transistor M1, which has a significant impact on noise from capacitor C1, is preferably a TGSA transistor or an LTPS transistor with low parasitic capacitance. Furthermore, transistors M3 and M4 are preferably vertical transistors with high on-state current.

[0207] Figure 18B The pixel circuit shown includes transistors M1 to M3, capacitor C1, and light-emitting element EL. The pixel circuit is connected to wirings G1 and G2 used as gate lines, wiring D1 used as source lines, and wirings V1 and V2 supplied with a fixed potential.

[0208] In transistor M1, the gate is connected to wiring G1, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one electrode of capacitor C1 and the gate of transistor M2. In transistor M2, the back gate and one of the source and drain are connected to the other electrode of capacitor C1, one electrode of the light-emitting element EL, and the other of the source and drain of transistor M3. The other of the source and drain is connected to wiring V1. In transistor M3, the gate is connected to wiring G1, and one of the source and drain is connected to wiring V2.

[0209] Transistor M2 is used as the drive transistor, and the other transistors are used as switches. Transistor M2 is preferably a TGSA transistor. Transistor M1, which has a significant impact on noise from capacitor C1, is preferably a TGSA transistor or an LTPS transistor with low parasitic capacitance. Additionally, transistor M3 is preferably a vertical transistor with a high on-state current.

[0210] Figure 18C The pixel circuit shown includes transistors M1 to M6, capacitor C1, and light-emitting element EL. The pixel circuit is connected to wirings G1 to G3 used as gate lines, wiring D1 used as source lines, and wirings V1 and V2 supplied with a fixed potential.

[0211] In transistor M1, the gate is connected to wiring G2, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one electrode of capacitor C1 and one of the source and drain of transistor M5. In transistor M2, the gate is connected to the other of the source and drain of transistor M3, the other electrode of capacitor C1, and the other of the source and drain of transistor M6. One of the source and drain is connected to one of the source and drain of transistor M4 and the other of the source and drain of transistor M6. The other of the source and drain is connected to wiring V2. In transistor M3, the gate is connected to wiring G1, and one of the source and drain is connected to wiring V1. In transistor M4, the gate is connected to wiring G3 and the gate of transistor M5. The other of the source and drain is connected to one electrode of the light-emitting element EL. The other of the source and drain of transistor M5 is connected to wiring V1. The gate of transistor M6 is connected to wiring G2.

[0212] Here, examples are shown where transistors M1 through M6 are p-channel transistors, but one or more transistors can also be n-channel transistors.

[0213] Transistor M2 is used as the driver transistor, and the other transistors are used as switches. Transistor M2 is preferably a p-channel LTPS transistor. Transistors M1, M3, and M6, which have a significant impact on noise from capacitor C1, are preferably TGSA transistors with low parasitic capacitance. Furthermore, transistors M4 and M5 are preferably vertical transistors or LTPS transistors with high on-state current. When using TGSA transistors and vertical transistors, n-channel transistors are preferred.

[0214] Figure 18D The pixel circuit shown includes transistors M1 to M6, capacitor C1, and light-emitting element EL. The pixel circuit is connected to wirings G1 to G3 used as gate lines, wiring D1 used as source lines, and wirings V1 and V2 supplied with a fixed potential.

[0215] In transistor M1, the gate is connected to wiring G2, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one electrode of capacitor C1 and one of the source and drain of transistor M5. In transistor M2, the gate is connected to the other electrode of capacitor C1 and the other of the source and drain of transistor M6, one of the source and drain is connected to one of the source and drain of transistor M4 and the other of the source and drain of transistor M6, and the other of the source and drain is connected to wiring V2. In transistor M3, the gate is connected to wiring G1, one of the source and drain is connected to wiring V1, and the other of the source and drain is connected to the other of the source and drain of transistor M4 and one electrode of the light-emitting element EL. The gate of transistor M4 is connected to wiring G3 and the gate of transistor M5. The other of the source and drain of transistor M5 is connected to wiring V1. The gate of transistor M6 is connected to wiring G2.

[0216] Here, examples are shown where transistors M1 through M6 are p-channel transistors, but one or more transistors can also be n-channel transistors.

[0217] Transistor M2 is used as the driver transistor, and the other transistors are used as switches. Transistor M2 is preferably a p-channel LTPS transistor. Transistors M1 and M6, which have a significant impact on noise from capacitor C1, are preferably TGSA transistors with low parasitic capacitance. Furthermore, transistors M3, M4, and M5 are preferably vertical transistors or LTPS transistors with high on-state current. When using TGSA transistors and vertical transistors, n-channel transistors are preferred.

[0218] Figure 19 The pixel circuit shown includes transistors M1 to M7, capacitor C1, and light-emitting element EL. The pixel circuit is connected to wirings G1 to G4 used as gate lines, wiring D1 used as source lines, and wirings V1 and V2 supplied with a fixed potential.

[0219] In transistor M1, the gate is connected to wiring G2, one of the source and drain is connected to wiring D1, and the other of the source and drain is connected to one of the source and drain of transistor M2 and one of the source and drain of transistor M3. In transistor M2, the gate is connected to wiring G3, and the other of the source and drain is connected to wiring V1. In transistor M3, the gate is connected to one electrode of capacitor C1, the other of the source and drain of transistor M4, and one of the source and drain of transistor M6; the back gate is connected to wiring V1, and the other of the source and drain is connected to one of the source and drain of transistor M4 and one of the source and drain of transistor M5. The gate of transistor M4 is connected to wiring G2. In transistor M5, the gate is connected to wiring G3, the other of the source and drain is connected to one electrode of the light-emitting element EL and one of the source and drain of transistor M7. In transistor M6, the gate is connected to wiring G1, and the other of the source and drain is connected to wiring V2. In transistor M7, the gate is connected to wiring G4, and the other of the source and drain is connected to wiring V2. The other electrode of capacitor C1 is connected to wiring V1.

[0220] Here, examples are shown where transistors M1 through M7 are p-channel transistors, but one or more transistors can also be n-channel transistors.

[0221] Transistor M3 is used as the driver transistor, while the other transistors are used as switches. Transistor M3 is preferably a p-channel LTPS transistor. Transistors M4 and M6, which significantly affect the noise of capacitor C1, are preferably TGSA transistors with low parasitic capacitance. Furthermore, transistors M1, M2, M5, and M7 are preferably vertical transistors or LTPS transistors with high on-state current. When using TGSA transistors and vertical transistors, n-channel transistors are preferred.

[0222] The above are examples of pixel circuits.

[0223] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0224] (Implementation Method 2) In this embodiment, Figures 20 to 22 are used to illustrate an electronic device according to one aspect of the present invention.

[0225] The electronic device of this embodiment includes a display device according to one aspect of the present invention in its display unit. The display device according to one aspect of the present invention is easily made to achieve high definition and high resolution. Therefore, it can be used in the display units of various electronic devices.

[0226] Furthermore, the semiconductor device according to one aspect of the present invention can also be used in parts of electronic devices other than the display unit. For example, low power consumption can be achieved by using the semiconductor device according to one aspect of the present invention in the control unit or the like of an electronic device, and is therefore preferred.

[0227] As electronic devices, in addition to large-screen electronic devices such as television sets, desktop or laptop personal computers, monitors for computers, digital signage, and large game machines such as pinball machines, other examples include digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, and sound reproduction devices.

[0228] In particular, because the display device of one aspect of the present invention can improve clarity, it can be suitably used in electronic devices that include a relatively small display section. Examples of such electronic devices include watch-type and bracelet-type information terminal devices (wearable devices), wearable devices that can be worn on the head, VR devices such as head-mounted displays, AR devices such as glasses, and MR devices.

[0229] The display device of one aspect of the present invention preferably has extremely high resolutions such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), 8K (7680×4320 pixels), etc. In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (clarity) of the display device of one aspect of the present invention is preferably 100 ppi or higher, preferably 300 ppi or higher, more preferably 500 ppi or higher, further preferably 1000 ppi or higher, even more preferably 2000 ppi or higher, even more preferably 3000 ppi or higher, still more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using the aforementioned display device with one or both of high resolution and high definition, the sense of realism and depth can be further enhanced. Furthermore, there is no particular limitation on the screen ratio (aspect ratio) of the display device according to one aspect of the present invention. For example, the display device can accommodate various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0230] The electronic device in this embodiment may also include a sensor (which has the function of detecting, identifying or measuring factors such as force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor or infrared radiation).

[0231] The electronic device of this embodiment can have various functions. For example, it can have the following functions: displaying various information (static images, dynamic images, text images, etc.) on the display unit; touch panel function; displaying calendar, date, or time, etc.; executing various software (programs); wireless communication function; reading programs or data stored in the storage medium; etc.

[0232] use Figures 20A to 20D This section describes an example of a wearable device that can be worn on the head. These wearable devices have at least one of the following functions: displaying AR content, displaying VR content, displaying SR content, and displaying MR content. When an electronic device has the function of displaying content from at least one of AR, VR, SR, MR, etc., it can enhance the user's sense of immersion.

[0233] Figure 20A The electronic device 700A shown and Figure 20B The electronic devices 700B shown include a pair of display panels 751, a pair of frames 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical components 753, a frame 757, and a pair of nose pads 758.

[0234] The display panel 751 can be used with a display device according to one aspect of the present invention. Therefore, an electronic device capable of displaying with extremely high clarity can be realized.

[0235] Both electronic devices 700A and 700B can project images displayed on the display panel 751 onto the display area 756 in the optical component 753. Because the optical component 753 is translucent, the user can see the image displayed on the display area by overlapping the transmitted image seen through the optical component 753. Therefore, both electronic devices 700A and 700B are capable of AR display.

[0236] Both electronic devices 700A and 700B can be equipped with cameras capable of capturing images of the front as imaging units. Furthermore, by incorporating accelerometers such as gyroscopes into both electronic devices 700A and 700B, the orientation of the user's head can be detected, and an image corresponding to that orientation can be displayed on the display area 756.

[0237] The communications section includes a wireless communication device through which image signals can be supplied. Furthermore, in addition to or in addition to the wireless communication device, a connector capable of connecting cables supplying image signals and power potential may also be included.

[0238] Electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly or via wired means, or both.

[0239] The frame 721 may also be equipped with a touch sensor module. The touch sensor module has the function of detecting whether the outer surface of the frame 721 is touched. Through the touch sensor module, various processes can be performed based on user tap or swipe operations. For example, a tap operation can perform processing such as temporarily pausing or replaying a moving image, while a swipe operation can perform processing such as fast forward or rewind. Furthermore, by providing a touch sensor module in each of the two frames 721, the operating range can be expanded.

[0240] Various touch sensors can be used as touch sensor modules. For example, capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, and optical sensors can be employed. In particular, capacitive or optical sensors are preferred for use in touch sensor modules.

[0241] When using optical touch sensors, photoelectric conversion elements can be used as the light-receiving element. The active layer of the photoelectric conversion element can use one or both of inorganic and organic semiconductors.

[0242] Figure 20C The electronic device 800A shown and Figure 20D The electronic devices 800B shown include a pair of display units 820, a frame 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0243] The display unit 820 can be equipped with a display device according to one aspect of the present invention. Therefore, an electronic device capable of displaying extremely high clarity can be realized. As a result, the user can experience a high degree of immersion.

[0244] The display unit 820 is located inside the housing 821 in a position visible through the lens 832. Furthermore, by displaying different images on each of the pair of display units 820, three-dimensional display utilizing parallax can be achieved.

[0245] Both electronic devices 800A and 800B can be referred to as VR-oriented electronic devices. Users who have installed electronic devices 800A or 800B can see the image displayed on the display unit 820 through the lens 832.

[0246] Electronic devices 800A and 800B preferably have a mechanism in which the left and right positions of the lens 832 and the display unit 820 can be adjusted so that the lens 832 and the display unit 820 are in the most suitable position according to the position of the user's eyes. Furthermore, it is preferable to have a mechanism in which the focus is adjusted by changing the distance between the lens 832 and the display unit 820.

[0247] The user can use the mounting unit 823 to attach electronic device 800A or electronic device 800B to their head. Note that... Figure 20C In the examples shown, the mounting part 823 has a shape similar to the temples (also called temple threads) of eyeglasses, but is not limited to this. As long as the user can attach it, the mounting part 823 can have, for example, a helmet-shaped or strap-shaped shape.

[0248] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras can be set to support various viewing angles such as telephoto and wide-angle.

[0249] Note that the example shown here includes an imaging unit 825, which can be a ranging sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object. In other words, the imaging unit 825 is one type of detection unit. For example, an image sensor or a distance image sensor such as LiDAR (Light Detection and Ranging) can be used as the detection unit. By using images acquired by a camera and images acquired by a distance image sensor, more information can be obtained, enabling more precise attitude control.

[0250] The electronic device 800A may also include a vibration mechanism used as a bone conduction headphone. For example, one or more of the display unit 820, the frame 821, and the mounting unit 823 may adopt a structure including this vibration mechanism. Thus, there is no need to separately install audio equipment such as headphones, earphones, or speakers; one can enjoy images and sound simply by installing the electronic device 800A.

[0251] Electronic devices 800A and 800B may also include input terminals. Cables supplying image signals from image output devices and the like, as well as power for charging batteries installed within the electronic devices, can be connected to the input terminals.

[0252] An electronic device according to one aspect of the present invention may also have the function of wirelessly communicating with the headset 750. The headset 750 includes a communication unit (not shown) and has wireless communication functionality. The headset 750 can receive information (e.g., voice data) from the electronic device via the wireless communication function. For example, Figure 20A The illustrated electronic device 700A has the function of transmitting information to the headset 750 via wireless communication. Additionally, for example... Figure 20C The electronic device 800A shown has the function of sending information to the headset 750 via wireless communication.

[0253] Electronic devices may also include an earphone unit. Figure 20B The illustrated electronic device 700B includes an earphone unit 727. For example, a structure in which the earphone unit 727 and the control unit are connected by a wire can be adopted. A portion of the wiring connecting the earphone unit 727 and the control unit can also be configured inside the housing 721 or the mounting portion 723.

[0254] same, Figure 20D The illustrated electronic device 800B includes an earphone unit 827. For example, a structure can be adopted in which the earphone unit 827 and the control unit 824 are connected by a wire. A portion of the wiring connecting the earphone unit 827 and the control unit 824 can also be disposed inside the housing 821 or the mounting portion 823. Furthermore, the earphone unit 827 and the mounting portion 823 can also include magnets. Thus, the earphone unit 827 can be magnetically secured to the mounting portion 823, making storage easy, which is preferable.

[0255] Electronic devices may also include an audio output terminal capable of connecting to headphones or headsets. Additionally, electronic devices may include one or both of an audio input terminal and an audio input mechanism. For example, a microphone or other sound-receiving device can be used as an audio input mechanism. By incorporating an audio input mechanism into the electronic device, it can be given a so-called headset function.

[0256] Thus, as an embodiment of the present invention, both eyeglass type (electronic device 700A and electronic device 700B, etc.) and goggle type (electronic device 800A and electronic device 800B, etc.) are preferred electronic devices.

[0257] One aspect of the present invention provides an electronic device that can transmit information to headphones in a wired or wireless manner.

[0258] Figure 21A The electronic device 6500 shown is a portable information terminal device that can be used as a smartphone.

[0259] Electronic device 6500 includes a frame 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0260] The display unit 6502 can use a display device according to one aspect of the present invention.

[0261] Figure 21B This is a cross-sectional schematic diagram of one end of the microphone 6506, including the frame 6501.

[0262] A light-transmitting protective component 6510 is provided on one side of the display surface of the frame 6501. The space surrounded by the frame 6501 and the protective component 6510 contains a display panel 6511, an optical component 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc.

[0263] The display panel 6511, optical component 6512, and touch sensor panel 6513 are fixed to the protective component 6510 using an adhesive layer (not shown).

[0264] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and this folded portion is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals disposed on a printed circuit board 6517.

[0265] The display panel 6511 can be used in a display device according to one aspect of the present invention. This allows for the realization of an extremely lightweight electronic device. Furthermore, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while minimizing the thickness of the electronic device. Additionally, by folding a portion of the display panel 6511 to provide a connection portion with the FPC 6515 on the back of the pixel section, a narrow-bezel electronic device can be achieved.

[0266] Figure 21C An example of a television device is shown. In the television device 7100, a display unit 7000 is assembled in a frame 7101. Here is shown the structure in which the frame 7101 is supported by a bracket 7103.

[0267] A display device according to one aspect of the present invention can be applied to the display unit 7000.

[0268] It can be operated using the operating switches included in the housing 7101 and the separately provided remote control 7111. Figure 21C The operation of the television device 7100 shown is illustrated. Alternatively, a touch sensor may be provided in the display unit 7000, allowing operation of the television device 7100 by touching the display unit 7000 with a finger or the like. Furthermore, a display unit for displaying data output from the remote control 7111 may be included in the remote control 7111. Channel and volume adjustments can be made using the operation keys or touch panel provided in the remote control 7111, and the images displayed on the display unit 7000 can also be manipulated.

[0269] In addition, the television device 7100 includes a receiver and a modem. It can receive general television broadcasts using the receiver. Furthermore, it can connect to a wired or wireless communication network via the modem to conduct one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0270] Figure 21D An example of a notebook computer is shown. The notebook computer 7200 includes a chassis 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is assembled in the chassis 7211.

[0271] A display device according to one aspect of the present invention can be applied to the display unit 7000.

[0272] Figure 21E and Figure 21F Here is an example of digital signage.

[0273] Figure 21E The digital sign 7300 shown includes a frame 7301, a display unit 7000, and a speaker 7303. It may also include LEDs, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0274] Figure 21F A digital sign 7400 is shown mounted on a cylindrical column 7401. The digital sign 7400 includes a display section 7000 disposed along the curved surface of the column 7401.

[0275] exist Figure 21E and Figure 21F In this embodiment, a display device according to one aspect of the present invention can be used in the display unit 7000.

[0276] The larger the display unit (7000), the more information it can provide at once. A larger display unit (7000) is also more likely to attract attention, which can improve the effectiveness of advertising.

[0277] By using a touch panel in the display unit 7000, not only can static or dynamic images be displayed on the display unit 7000, but users can also operate it intuitively, making it preferable. Furthermore, when used to provide information such as route information or traffic information, intuitive operation enhances ease of use.

[0278] like Figure 21E and Figure 21FAs shown, digital signage 7300 or digital signage 7400 preferably connects wirelessly with information terminal devices 7311 or 7411, such as smartphones carried by the user. For example, advertising information displayed on display unit 7000 can be displayed on the screen of information terminal device 7311 or information terminal device 7411. Furthermore, the display on display unit 7000 can be switched by operating information terminal device 7311 or information terminal device 7411.

[0279] The game can be executed on the digital signage 7300 or 7400 using the screen of information terminal device 7311 or 7411 as the operating unit (controller). Thus, multiple users can participate in the game simultaneously and enjoy the experience.

[0280] Figures 22A to 22G The electronic device shown includes a frame 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), a connection terminal 9006, a sensor 9007 (which has the function of detecting, identifying or measuring the following factors: force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor or infrared radiation), a microphone 9008, etc.

[0281] exist Figures 22A to 22G In this embodiment, a display device according to one aspect of the present invention can be used in the display unit 9001.

[0282] Figures 22A to 22G The electronic device shown has various functions. For example, it may have the following functions: displaying various information (still images, moving images, and text images, etc.) on a display unit; a touch panel function; displaying a calendar, date, or time, etc.; controlling processing using various software (programs); wireless communication function; reading and processing programs or data stored in a storage medium; etc. Note that the functions of the electronic device are not limited to the above functions, and it may have various functions. The electronic device may also include multiple display units. In addition, a camera or the like may be installed in the electronic device to give it the following functions: capturing still or moving images and storing the captured images in a storage medium (external storage medium or storage medium built into the camera); displaying the captured images on a display unit; etc.

[0283] The following is a detailed explanation. Figures 22A to 22G The electronic device shown.

[0284] Figure 22AThis is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 can be used, for example, as a smartphone. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, etc., may also be included in the portable information terminal 9101. Furthermore, the portable information terminal 9101 can display text or image information on multiple surfaces. Figure 22A The image shows an example displaying three icons 9050. Alternatively, information 9051, shown as a dashed rectangle, can be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of received emails, SNS messages, or phone calls; the subject of the email or SNS message; the sender's name; the date; the time; remaining battery level; and radio wave strength. Alternatively, icons 9050 can be displayed in the same location where information 9051 is displayed.

[0285] Figure 22B This is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 has the function of displaying information on three or more surfaces of the display unit 9001. Here, examples are shown where information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9102 is placed in a jacket pocket, the user can check the information 9053 displayed in a position seen from above the portable information terminal 9102. For example, the user can check this display without taking the portable information terminal 9102 out of the pocket, thereby enabling them to determine, for example, whether to answer a phone call.

[0286] Figure 22C This is a perspective view of a tablet terminal 9103. The tablet terminal 9103 can, for example, execute various application software such as mobile phone, email, and article reading and editing, music playback, network communication, and computer games. The tablet terminal 9103 includes a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the frame 9000; operation keys 9005 serving as operating buttons on the left side of the frame 9000; and a connection terminal 9006 on the bottom surface.

[0287] Figure 22D This is a perspective view showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smartwatch (registered trademark). Furthermore, the display surface of the display unit 9001 is curved, allowing display along its curved surface. In addition, the portable information terminal 9200 can perform hands-free calls, for example, by communicating with a headset capable of wireless communication. Furthermore, by utilizing the connection terminal 9006, the portable information terminal 9200 can transmit data or charge with other information terminals. Charging can also be performed wirelessly.

[0288] Figures 22E to 22G This is a perspective view showing the foldable portable information terminal 9201. Additionally, Figure 22E This is a 3D view of the portable information terminal 9201 in its unfolded state. Figure 22G It is a 3D image of the folded state. Figure 22F From Figure 22E status and Figure 22G The portable information terminal 9201 is a three-dimensional representation of the state transitioning between different states. In its folded state, it is highly portable, while in its unfolded state, it offers excellent browsing capabilities due to its large, seamlessly integrated display area. The display unit 9001 included in the portable information terminal 9201 is supported by three frames 9000 connected by hinges 9055. The display unit 9001 can be bent, for example, within a radius of curvature of 0.1 mm or more and 150 mm or less.

[0289] At least a portion of this embodiment can be implemented in combination with other embodiments described in this specification.

[0290] [Symbol Explanation] 10: Display device, 10a: Display device, 10b: Display device, 10c: Display device, 10d: Semiconductor device, 10e: Display device, 10f: Display device, 10g: Display device, 10h: Display device, 10i: Display device, 10j: Display device, 10k: Display device, 10l: Display device, 10m: Display device, 10n: Display device, 10o: Display device, 10p: Display device, 10q: Display device, 10r: Display device, 10s: Display device, 10t: Display device, 10u: Display device, 10v: Display device, 10w: Display device 10x: Display device, 10y: Display device, 10z: Display device, 10aa: Display device, 10ab: Display device, 10ac: Display device, 10ad: Display device, 10ae: Display device, 10af: Display device, 10ag: Display device, 10ah: Display device, 10ai: Display device, 10aj: Display device, 10ak: Display device, 10al: Display device, 10am: Display device, 10an: Display device, 10ao: Display device, 10ap: Display device, 10aq: Display device, 10ar: Display device, 11: Insulation Layer, 12: Connector, 13: Connector, 14: Connector, 21: Semiconductor layer, 21a: Semiconductor layer, 22: Insulating layer, 22a: Insulating layer, 23: Conductive layer, 23b: Conductive layer, 23c: Conductive layer, 23d: Conductive layer, 24: Conductive layer, 24a: Conductive layer, 24b: Conductive layer, 24d: Conductive layer, 25: Conductive layer, 31: Conductive layer, 31a: Conductive layer, 31d: Conductive layer, 31e: Conductive layer, 31f: Conductive layer, 32: Conductive layer, 32a: Conductive layer, 33: Conductive layer, 34: Conductive layer, 34a: Conductive layer, 34b: Conductive layer, 35: Conductive layer 41: Insulating layer, 42: Insulating layer, 43: Insulating layer, 44: Insulating layer, 45: Insulating layer, 46: Insulating layer, 51: Transistor, 52: Transistor, 53: Transistor, 61: Semiconductor layer, 62: Insulating layer, 63: Conductive layer, 63a: Conductive layer, 64: Conductive layer, 64a: Conductive layer, 65: Conductive layer, 70: Pixel, 71B: Sub-pixel, 71G: Sub-pixel, 71R: Sub-pixel, 100: Display device, 101: Pixel unit, 102: Source line drive circuit unit, 103: Gate line drive circuit unit, 104: Protection circuit unit, 105: Touch sensor drive circuit unit.

Claims

1. A display device, comprising: The first transistor in a vertical transistor configuration; The second transistor of a top-gate transistor; First insulating layer; as well as First conductive layer, The first transistor includes an upper electrode and a lower electrode. The upper electrode and the second transistor are located on the first insulating layer. The first conductive layer has a region located below the first insulating layer and overlapping with the second transistor. Furthermore, the first conductive layer and the lower electrode are located on the same surface and contain the same material.

2. The display device according to claim 1, The first transistor includes a first semiconductor layer. The second transistor includes a second semiconductor layer. The first conductive layer is disposed in a manner that overlaps with the second semiconductor layer. Furthermore, the first semiconductor layer and the second semiconductor layer have portions located on the same surface and contain the same material.

3. The display device according to claim 1, further comprising: A display element connected to the second transistor.

4. The display device according to claim 3, The display element is a liquid crystal element.

5. The display device according to claim 3, The display element is a light-emitting element.

Images