Liquid crystal display device

Abstract

To provide an input-output device with high reliability and smaller thickness.SOLUTION: An input-output device includes a first pixel electrode, a second pixel electrode, a first common electrode, a second common electrode, a liquid crystal, a first insulating film, a second insulating film, and a transistor. The first common electrode functions as one electrode of a detection element. The second common electrode functions as the other electrode of the detection element. The transistor includes a first gate, a second gate, and a semiconductor layer. The pixel electrode, the common electrode, and the second gate exist on different surfaces. The second gate includes one or more kinds of metal elements included in the semiconductor layer. Preferably, the second gate, the pixel electrode, and the common electrode contain one or more kinds of metal elements included in the semiconductor layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to an input / output device and an electronic device.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one embodiment is a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an Sub-devices, lighting devices, input devices (e.g., touch sensors), output devices, input / output devices (e.g., For example, touch panels, their driving methods, or their manufacturing methods. Some examples include: [Background technology]

[0003] It is used in many flat panel displays, such as liquid crystal displays and light-emitting displays. The transistors used are made of amorphous silicon and single-crystal silicon formed on a glass substrate. The silicon semiconductor is made of silicon or polycrystalline silicon. Semiconductor transistors are also used in integrated circuits (ICs).

[0004] In recent years, metal oxides that exhibit semiconducting properties have been used in transistors instead of silicon semiconductors. In this specification, metal oxides that exhibit semiconducting properties are referred to as oxide semiconductors. For example, Patent Documents 1 and 2 describe the following as oxide semiconductors: A transistor using zinc oxide or In-Ga-Zn oxide is manufactured, and the transistor A technique for using a capacitor as a switching element for a pixel of a display device has been disclosed.

[0005] In addition, the display device is provided with a user interface that allows input by touching the screen with a finger or the like. There is a demand for touch panels with added functionality.

[0006] A display device or a display module equipped with a touch sensor is called a touch panel or a touch screen. Also, devices that have touch sensors but no display elements are called It is sometimes called a touch panel. Therefore, a display device or display device equipped with a touch sensor The modules are used as display devices with touch sensors, display devices with touch panels, and display devices with touch panels. It is sometimes called a touch sensor or a touch panel with a display device. A display device equipped with a touch sensor will be referred to as a touch panel.

[0007] For example, Patent Documents 3 to 6 disclose touch panels using liquid crystal elements as display elements. It has been disclosed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-197685 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-44537 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-178847 [Patent Document 6] US Patent Application Publication No. 2008 / 0158183 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of one embodiment of the present invention is to reduce the thickness of an input / output device. Another object of the present invention is to reduce the weight of an input / output device. One object is to provide an output device.

[0010] Another object of one embodiment of the present invention is to provide a highly reliable input / output device. Another object of one embodiment of the present invention is to provide an input / output device with high detection sensitivity. Another object of one embodiment of the present invention is to provide a novel input / output device or the like.

[0011] The description of these problems does not preclude the existence of other problems. It is not necessary for the embodiments to solve all of these problems. It is possible to extract other issues from the description of the claims, etc. [Means for solving the problem]

[0012] One aspect of the present invention is a liquid crystal display device including a first pixel electrode, a second pixel electrode, a first common electrode, and a second common electrode. The input / output device includes a liquid crystal, a first insulating film, a second insulating film, and a transistor. One common electrode can function as one electrode of the sensing element. The second common electrode can , which can serve as the other electrode of the sensing element. The semiconductor layer has a second gate and a semiconductor layer. The semiconductor layer has a channel formation region formed of an oxide semiconductor. The second gate includes an oxide conductor. The oxide conductor is included in an oxide semiconductor. The input / output device of one embodiment of the present invention has a first gate and a second gate, A semiconductor layer is provided, a second gate is provided on the semiconductor layer, and a first insulating film is provided on the second gate. a first pixel electrode, a second pixel electrode, a first common electrode, and a The first pixel electrode and the first common electrode are connected to each other via a second insulating film. The second pixel electrode and the second common electrode are connected via a second insulating film. The first pixel electrode, the second pixel electrode, the first common electrode, and the second pixel electrode have overlapping portions. The first pixel electrode and the second pixel electrode are spaced apart on the same plane. The first common electrode and the second common electrode are located on the same plane and spaced apart from each other.

[0013] At least one of the display unit and the driver circuit unit includes the above-described transistor. According to one embodiment of the present invention, there is provided an input / output device including two of the above-described transistors. In one, the source or drain is electrically connected to the first pixel electrode, and in the other The source or drain may be electrically connected to the second pixel electrode. The transistor may be located in the drive circuit section.

[0014] Alternatively, in each of the above configurations, the second gate is electrically connected to the first gate. Good too.

[0015] Alternatively, in each of the above configurations, a second insulating film is formed on the first pixel electrode and the second pixel electrode. The second insulating film may have a first common electrode and a second common electrode on it. In each of the above configurations, a second insulating film is provided on the first common electrode and the second common electrode. The first pixel electrode and the second pixel electrode may be provided on the second insulating film.

[0016] Alternatively, in each of the above configurations, the first pixel electrode and the second pixel electrode are each made of an oxide. The first common electrode may have at least one metal element contained in a semiconductor. and the second common electrode each contain at least one metal element contained in an oxide semiconductor. It may be possible.

[0017] Alternatively, in each of the above structures, the oxide semiconductor and the oxide conductor may each contain indium. Furthermore, the first pixel electrode and the second pixel electrode may each have an oxide containing Each of the first common electrode and the second common electrode may have an oxide containing indium. The common electrodes may each comprise an oxide containing indium.

[0018] Alternatively, in each of the above structures, the oxide semiconductor and the oxide conductor are each In-M1 -Zn oxide (M1 is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf) Furthermore, the first pixel electrode and the second pixel electrode may each have the above-mentioned I The first common electrode and the second common electrode may have n-M1-Zn oxide. may each have the In-M1-Zn oxide.

[0019] Alternatively, in each of the above configurations, the first pixel electrode, the second pixel electrode, the first common electrode, and Each of the second common electrodes may have a function of transmitting visible light.

[0020] Alternatively, in each of the above configurations, a first conductive film is provided between the first insulating film and the first common electrode. However, the resistivity of the first conductive film is lower than the resistivity of the first common electrode. The first insulating film may be electrically connected to the first common electrode. a second conductive film, the resistivity of which is lower than the resistivity of the second common electrode; The second conductive film is electrically connected to the second common electrode, and the first conductive film and the second conductive film are , may be spaced apart on the same plane.

[0021] Alternatively, in each of the above structures, a light-shielding film is provided, and the light-shielding film is the first conductive film or the second conductive film. The liquid crystal layer may have a portion overlapping with at least one of the above through the liquid crystal.

[0022] In addition, one embodiment of the present invention is a method for manufacturing a flexible printed circuit board (FPC) in the input / output device. ed circuit) or TCP (Tape Carrier Package) Modules with connectors such as COG (Chip On Glass) ) method, COF (Chip On Film) method, etc. These are modules such as:

[0023] Alternatively, one aspect of the present invention is a device including the module, an antenna, a battery, a housing, and a speaker. , a microphone, an operation switch, or an operation button, is. [Effects of the Invention]

[0024] According to one embodiment of the present invention, an input / output device can be made thinner. This allows the input / output device to be lightweight. It is possible to provide a simple input / output device.

[0025] According to one embodiment of the present invention, a highly reliable input / output device can be provided. According to one embodiment of the present invention, an input / output device with high detection sensitivity can be provided. According to one embodiment of the present invention, a novel input / output device or the like can be provided.

[0026] The description of these effects does not preclude the existence of other effects. The embodiments do not necessarily have all of these effects. It is possible to extract other effects from the descriptions in the paragraphs. [Brief explanation of the drawings]

[0027] [Figure 1] 1A and 1B are a top view and a cross-sectional view illustrating an example of an input / output device. [Figure 2] FIG. 1 is a cross-sectional view showing an example of an input / output device. [Figure 3] FIG. 1 is a cross-sectional view showing an example of an input / output device. [Figure 4] FIG. 1 is a cross-sectional view showing an example of an input / output device. [Figure 5] FIG. 1 is a cross-sectional view showing an example of an input / output device. [Figure 6] FIG. 1 is a cross-sectional view showing an example of an input / output device. [Figure 7] FIG. 2 is a diagram showing an example of a detector element and a pixel. [Figure 8] FIG. 1 is a diagram showing an example of the operation of a detector element and a pixel. [Figure 9] FIG. 2 is a top view showing an example of a detector element and a pixel. [Figure 10] FIG. 2 is a top view showing an example of a sensing element. [Figure 11] FIG. 2 is a top view showing an example of a sensing element. [Figure 12] FIG. 1 is a top view showing an example of an input / output device. [Figure 13] FIG. 1 is a top view showing an example of an input / output device. [Figure 14] FIG. 1 is a top view showing an example of an input / output device. [Figure 15] FIG. 1 is a block diagram showing an example of a touch panel module. [Figure 16] FIG. 1 is a diagram showing an example of a touch panel module. [Figure 17] 1A to 1C are cross-sectional views illustrating an example of a method for manufacturing a transistor or the like. [Figure 18]1A to 1C are cross-sectional views illustrating an example of a method for manufacturing a transistor or the like. [Figure 19] 1A to 1C are cross-sectional views illustrating an example of a method for manufacturing a transistor or the like. [Figure 20] 1A to 1C are cross-sectional views illustrating an example of a method for manufacturing a transistor or the like. [Figure 21] FIG. 1 is a cross-sectional view illustrating an example of a transistor. [Figure 22] 1A and 1B are a top view and a cross-sectional view illustrating an example of a transistor. [Figure 23] FIG. 1 is a cross-sectional view illustrating an example of a transistor. [Figure 24] FIG. 1 is a diagram illustrating a band structure. [Figure 25] FIG. 1 is a cross-sectional view illustrating an example of a transistor. [Figure 26] 1A and 1B are diagrams illustrating structural analysis of a CAAC-OS and a single-crystal oxide semiconductor by XRD, and a selected-area electron diffraction pattern of a CAAC-OS. [Figure 27] Cross-sectional TEM image of CAAC-OS, as well as planar TEM image and its image analysis image. [Figure 28] Electron diffraction pattern of nc-OS and cross-sectional TEM image of nc-OS. [Figure 29] Cross-sectional TEM image of a-like OS. [Figure 30] FIG. 1 shows the change in the crystalline part of an In-Ga-Zn oxide due to electron irradiation. [Figure 31] FIG. 1 is a diagram showing an example of a touch panel module. [Figure 32] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 33] 1A and 1B are diagrams illustrating examples of electronic devices. [Figure 34] FIG. 1 is a cross-sectional view showing an example of an input / output device. [Figure 35] 1 is a photograph showing an input / output device according to an embodiment. [Figure 36] FIG. 10 is a diagram illustrating the measurement results of the XRD spectrum of a sample. [Figure 37] TEM image of a sample and a diagram illustrating an electron beam diffraction pattern. [Figure 38] FIG. 1 is a diagram illustrating EDX mapping of a sample. DETAILED DESCRIPTION OF THE INVENTION

[0028] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. The present invention is not limited to the above embodiments, and various changes and modifications may be made in the form and details thereof without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that the present invention can be achieved by the following embodiments. It should not be construed as being limited to the contents described.

[0029] In the configuration of the invention described below, the same parts or parts having similar functions are designated by the same reference numerals. The same reference numerals are used in common among different drawings, and the repeated explanations thereof will be omitted. When referring to a function, the hatch pattern may be the same and no particular symbol may be added.

[0030] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily the same as those in the actual device for ease of understanding. Therefore, the disclosed invention may not necessarily represent the actual position, size, range, etc. The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0031] The words "film" and "layer" may be used interchangeably depending on the situation. For example, the term "conductive film" can be used interchangeably with the term "conductive layer." Alternatively, for example, the term "insulating layer" may be changed to "insulating layer". It may be possible to change the term to "insulating film."

[0032] In this specification, "parallel" means that two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, it includes the case of -5° or more and 5° or less. "Line" refers to the state in which two straight lines are arranged at an angle between -30° and 30°. "Perpendicular" means that two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, it also includes the case where the angle is between 85° and 95°. This refers to a state in which two straight lines are arranged at an angle of 60° or more and 120° or less.

[0033] In addition, in this specification, when the crystal is a trigonal or rhombohedral crystal, it is expressed as a hexagonal crystal system.

[0034] (Embodiment 1) In this embodiment, an input / output device of one embodiment of the present invention will be described with reference to FIGS. 1 to 16. .

[0035] An input / output device of one embodiment of the present invention has a function of displaying an image, a function as a touch sensor, and It is an in-cell type touch panel having the above structure.

[0036] The display element included in the input / output device of one embodiment of the present invention is not limited to a liquid crystal element, a MEMS (Micro Electro Mechanical Systems) element, or the like. Optical elements using cro Electro Mechanical Systems, Organic EL (Electro Luminescence) elements and light-emitting diodes (LEDs) Light-emitting diodes (LEDs), electrophoretic elements, and various other Such an element can be applied as a display element.

[0037] In this embodiment, a transmissive liquid crystal display device using a lateral electric field type liquid crystal element will be described as an example. Reveal.

[0038] There is no limitation on the type of detector element (also referred to as a sensor element) included in the input / output device of one embodiment of the present invention. Various sensors that can detect the proximity or contact of a detection object such as a pen or stylus are available. It can be applied as a knowledge element.

[0039] For example, the sensor types include capacitance type, resistive film type, surface acoustic wave type, and infrared type. Various methods can be used, such as optical methods and pressure-sensitive methods.

[0040] In this embodiment, an input / output device having a capacitance type detection element will be described as an example.

[0041] The capacitance type includes a surface capacitance type, a projected capacitance type, etc. The capacitance type includes the self-capacitance type and the mutual capacitance type. This is preferable because it enables simultaneous multi-point detection.

[0042] In the input / output device according to one embodiment of the present invention, only a substrate supporting a display element is provided with an electrode constituting a detector element. The input / output device of one embodiment of the present invention is a full-in-cell touch panel. Another in-cell type touch panel is a device that supports the display element. The structure in which electrodes constituting the sensing element are provided on both the facing substrate and the counter substrate or only on the counter substrate. In comparison with these configurations, the full-in-cell touch panel has a counter substrate configuration. This is preferable because it allows for simplification.

[0043] In the input / output device of one embodiment of the present invention, an electrode constituting a display element is connected to an electrode constituting a sensor element. This is preferable because it can simplify the manufacturing process and reduce manufacturing costs.

[0044] By applying one embodiment of the present invention, a display panel and a sensing element that are separately manufactured can be bonded together. In comparison with a configuration in which a detector element is fabricated on the opposing substrate side, the input / output device can be made thinner or The weight can be reduced, or the number of parts of the input / output device can be reduced.

[0045] The input / output device according to one embodiment of the present invention includes an FPC that supplies a signal for driving a pixel and a The FPC that supplies the signals that operate the electronic device is placed on one side of the board. It is easy to incorporate into the FPC and it is possible to reduce the number of parts. The signals for driving the pixels and the signals for driving the detector elements may be provided by the signal source.

[0046] The configuration of the input / output device of one embodiment of the present invention will be described below.

[0047] [Example 1 of cross-sectional configuration of input / output device] FIG. 1A shows a top view of the input / output device 300, and FIG. 1B shows a part of FIG. 1A. 1 shows a cross-sectional view between dashed dotted lines AB and dashed dotted lines CD.

[0048] As shown in FIG. 1A, the input / output device 300 includes a display portion 301 and a scanning line driver circuit 302. The display unit 301 has a plurality of pixels 303, a plurality of signal lines, and a plurality of scanning lines. The display unit 301 also functions as an input unit. The unit 301 includes a plurality of detection elements that detect contact or proximity of an object to be detected with the input / output device 300. The scanning line driver circuit 302 has a function as a touch sensor. The pixel 303 has a function of outputting a scanning signal to a scanning line corresponding to the pixel 303. The pixel 303 has a plurality of sub-pixels. FIG. 1A shows an example in which the pixel 303 has three subpixels. In one embodiment of the present invention, Not limited to.

[0049] FIG. 1A shows an example in which the input / output device 300 has a scanning line driver circuit. The input / output device 300 includes a scanning line driving circuit, a signal line driving circuit, and It is not necessary to have all of the sensor drive circuits, and it is also possible to have one or more of them.

[0050] In the input / output device 300, the IC 268 is mounted on the substrate 211 by a mounting method such as the COG method. The IC 268 is equipped with, for example, a signal line driving circuit, a scanning line driving circuit, and a sensor driving circuit. It has one or more of the following operating circuits.

[0051] Furthermore, the input / output device 300 is electrically connected to an FPC 269. Signals are supplied from the outside to IC268 and the scanning line driver circuit via FPC2. A signal can be output from IC268 to the outside via 69.

[0052] An IC may be mounted on the FPC 269. For example, the FPC 269 may include a signal line driver. An IC having one or more of the following circuits is implemented: a driving circuit, a scanning line driving circuit, and a sensor driving circuit. For example, the COF method or TAB (Tape Automated Board) By using mounting methods such as the mounting method, ICs can be mounted on FPC269. .

[0053] For example, the IC 268 may include a signal line driver circuit and a sensor driver circuit. For example, IC 268 has a signal line driver circuit, and an IC mounted on FPC 269 is The sensor may have a driving circuit.

[0054] As shown in FIG. 1B, the input / output device 300 includes a transistor 201a , a transistor 203a, a connecting portion 205a, a liquid crystal element 207a, and the like.

[0055] FIG. 1B shows a cross section of one subpixel as an example of the display portion 301. For example, A single pixel is made up of a red sub-pixel, a green sub-pixel, and a blue sub-pixel. By configuring the display unit 301, full color display can be performed. The colors that the pixels exhibit are not limited to red, green, and blue. For example, the pixels may be white, yellow, magenta, etc. Alternatively, a sub-pixel that exhibits a color such as cyan may be used.

[0056] The transistors 201a and 203a include a gate electrode 221, an insulating film 213, an oxide semiconductor film 223, a source electrode 225a, and a drain electrode 225b. a further includes a conductive film 226, an insulating film 215, and an oxide conductive film 227. The insulating film 215 can also be considered a component of the transistor 203a.

[0057] The gate electrode 221 and the oxide conductive film 227 can each function as a gate. The transistor 201a has an oxide semiconductor film where a channel is formed, and two gates are connected to the oxide semiconductor film. The gate electrode 221 and the oxide conductive film 227 are sandwiched between the gate electrode 221 and the oxide conductive film 227 via the conductive film 226. In this way, the transistor with the two gates electrically connected The field-effect mobility of an on-transistor can be increased compared to other transistors. As a result, it is possible to create a circuit that can operate at high speed. Furthermore, it is possible to reduce the area occupied by the circuit section. By applying resistors, the input / output device becomes larger or more precise, and the number of wirings increases. It is also possible to reduce the signal delay in each wiring, and to suppress display unevenness. Furthermore, by applying such a configuration, a highly reliable transistor can be realized. It is possible.

[0058] Transistors 201a and 203a may be of the same structure or of different structures. That is, the transistors in the driver circuit portion and the transistors in the display portion have the same structure. The driving circuit section may have a plurality of transistor structures. The display section may have a transistor with a plurality of structures. For example, among the shift register circuit, the buffer circuit, and the protection circuit included in the scanning line driver circuit, , one or more circuits use transistors with two gates electrically connected It is preferable.

[0059] The transistors 201a and 203a are covered with an insulating film 217 and an insulating film 219. The insulating film 217 and the insulating film 219 are used as components of the transistors 201a and 203a. The insulating film 217 can be regarded as a material for preventing impurities from entering the semiconductor that constitutes the transistor. For example, the insulating film 217 may be formed of a material that can suppress diffusion of water, hydrogen, etc. It is preferable to use a material that is difficult for impurities to diffuse. It is preferable to select an insulating film having a planarizing function in order to reduce the surface irregularities that cause the problem.

[0060] The transistor 201a includes an oxide semiconductor film 223 as a semiconductor layer and an oxide semiconductor film 224 as a gate. The oxide semiconductor film 223 and the oxide conductive film 227 are used. The layer 227 is preferably formed using an oxide semiconductor.

[0061] The resistivity of an oxide semiconductor can be easily controlled in the manufacturing process of an input / output device. Therefore, it can be suitably used as a material for a semiconductor film and a conductive film. By using an oxide semiconductor having a semiconductor element in two or more layers constituting an input / output device, It is possible to share manufacturing equipment (e.g., film forming equipment, processing equipment, etc.) in two or more processes. Therefore, the manufacturing cost can be reduced.

[0062] In addition, oxide semiconductors are materials that transmit visible light, and are therefore suitable for elements that transmit visible light. It can be used for.

[0063] In addition, by forming the oxide semiconductor film 223 and the oxide conductive film 227 using the same metal element, For example, a metal oxide target having the same metal composition can be manufactured by using a metal oxide target having the same metal composition. By using a metal oxide with the same metal composition, the manufacturing cost can be reduced. By using an oxide target, the etching gas or However, the same etching solution can be used for the oxide semiconductor film 223 and the oxide semiconductor film 224. The metallic conductive films 227 may have different compositions even if they contain the same metal elements. For example, During the manufacturing process of the input / output device, metal elements in the film may be released, resulting in a different metal composition. .

[0064] The transistors 201a and 203a are made of highly purified oxide semiconductors that suppress the formation of oxygen vacancies. It is preferable that the transistor has a conductive film 223. This allows the current to flow in the off state of the transistor. Therefore, the retention time of an electric signal such as an image signal can be reduced. The write interval can be set to a long value when the power is on. This reduces the frequency of flash operations, thereby reducing power consumption.

[0065] Furthermore, the transistors 201a and 203a have relatively high field-effect mobility. High-speed driving is possible. Such high-speed driving transistors are used in input / output devices. This allows the transistors of the display section and the transistors of the driver circuit section to be formed on the same substrate. That is, a semiconductor formed by a silicon wafer or the like can be used as a drive circuit. Since there is no need to use a physical device, the number of parts in the input / output device can be reduced. The display also uses transistors capable of high-speed operation, providing high-quality images. It is possible.

[0066] The liquid crystal element 207a is in FFS (Fringe Field Switching) mode. The liquid crystal element 207a is a liquid crystal element to which the conductive film 251, the conductive film 252, and The liquid crystal 249 is formed by an electric field generated between the conductive film 251 and the conductive film 252. The conductive film 251 can function as a pixel electrode. The conductive film 252 can function as a common electrode.

[0067] By using a conductive material that transmits visible light for the conductive films 251 and 252, The device 300 can function as a transmissive liquid crystal display device. The conductive film 251 is made of a conductive material that reflects visible light, and the conductive film 252 is made of a conductive material that transmits visible light. By using this, the input / output device 300 can function as a reflective liquid crystal display device. Cut.

[0068] Examples of conductive materials that transmit visible light include indium (In), zinc (Zn), and tin. It is preferable to use a material containing one selected from the group consisting of indium oxide (Sn). , Indium Tin Oxide (ITO), Indium Zinc Oxide, Indium Oxide with Tungsten Oxide, Indium Oxide with Tungsten Oxide Zinc oxide, indium oxide with titanium oxide, indium tin oxide with titanium oxide Indium tin oxide doped with silicon oxide, zinc oxide, zinc oxide doped with gallium, etc. It is also possible to use a film containing graphene. The graphene oxide film can be formed by, for example, reducing a film containing graphene oxide.

[0069] It is preferable to use an oxide conductive film for the conductive film 251. The oxide conductive film is preferably a metal film containing a metal element contained in the oxide semiconductor film 223. For example, the conductive film 251 may contain indium. Preferably, In-M-Zn oxide (wherein M is Al, Ti, Ga, Ge, Y, Zr, La, Ce) , Sn, Mg, Nd, or Hf) film is more preferable. The film preferably contains indium, and is more preferably an In-M-Zn oxide film. It's nice.

[0070] Note that at least one of the conductive films 251 and 252 is formed using an oxide semiconductor. As described above, oxide semiconductors having the same metal element may be used to configure an input / output device. By using this for two or more layers, the manufacturing equipment (for example, film forming equipment, processing equipment, etc.) can be doubled. Since the above steps can be performed in common, the manufacturing cost can be reduced.

[0071] For example, a silicon nitride film containing hydrogen is used for the insulating film 253, and an oxide semiconductor film is used for the conductive film 251. When the insulating film 253 is used, the conductivity of the oxide semiconductor is increased by hydrogen supplied from the insulating film 253. It is possible.

[0072] Examples of conductive materials that reflect visible light include aluminum, silver, and metal materials thereof. Examples of suitable materials include alloys containing such materials.

[0073] The conductive film 251 functioning as a pixel electrode is connected to the source or drain of the transistor 203a. Here, the conductive film 251 is electrically connected to the drain electrode 225b. Here is an example of this.

[0074] The conductive film 252 has a comb-like top surface (also referred to as a planar shape) or a top surface provided with slits. The insulating film 253 is provided between the conductive film 251 and the conductive film 252. The conductive film 251 has a portion overlapping with the conductive film 252 with the insulating film 253 interposed therebetween. In the region where the conductive film 251 and the colored film 241 overlap, a conductive film 252 is disposed on the conductive film 251. It has a part that is not placed.

[0075] A conductive film 255 is provided over the insulating film 253. The conductive film 255 is They are electrically connected and can function as auxiliary wiring for the conductive film 252. By providing auxiliary wiring that electrically connects the common electrode, the voltage drop caused by the resistance of the common electrode is suppressed. In this case, the conductive film containing the metal oxide and the conductive film containing the metal can be controlled. When a laminated structure is used, it is formed by a patterning technique using a halftone mask. This is preferable because it simplifies the process.

[0076] The conductive film 255 has a lower resistance value than the conductive film 252. The conductive film 255 is, for example, Molybdenum, titanium, chromium, tantalum, tungsten, aluminum, copper, silver, neodymium It is made of metal materials such as aluminum and scandium, or alloy materials containing these elements, and is used in single layer or laminated layers. It can be formed in layers.

[0077] The conductive film 255 is positioned so as to overlap the light-shielding film 243 etc. so as not to be visible to the user of the input / output device. It is preferable that the sensor is provided in a position.

[0078] The connection portion 205a is connected to the scanning line driving circuit 302 through an external signal (video signal, clock signal, etc.). It is electrically connected to an external input terminal that transmits signals (start signal, reset signal, etc.) or potential. Here, an example is shown in which FPC269 is provided as an external input terminal.

[0079] The connection portion 205a has a conductive film 231 on the insulating film 213, and a conductive film 23 3, and a conductive film 235 is provided over the conductive film 233. The conductive film 235 is electrically connected to the conductive film 235 via the connector 267. It is electrically connected to FPC269.

[0080] The conductive film 231 is formed on the source electrode 225a and the drain electrode 225b of the transistors 201a and 203a. The conductive film 233 can be formed using the same material and process as the inner electrode 225b. The conductive film 251 of the liquid crystal element 207a can be formed using the same material and process. The conductive film 235 is formed using the same material and process as the conductive film 252 of the liquid crystal element 207a. In this way, the conductive film that constitutes the connection portion 205a can be formed by If the electrodes and wiring used in the drive circuit are made of the same material and in the same process, the number of processes can be prevented from increasing. This is preferable because it can be done easily.

[0081] The substrate 261 is provided with a colored film 241, a light-shielding film 243, and an insulating film 245. 1(B) shows an example in which the thickness of the substrate 261 is thinner than the thickness of the substrate 211. The embodiment is not limited to this. One of the substrates 261 and 211 may be thinner than the other. If the substrate on the display surface side (the side closest to the object to be detected) is made thinner, the detection This is preferable because it can increase the detection sensitivity of the element.

[0082] The colored film 241 has a portion overlapping with the liquid crystal element 207a. The sensor 201 has a portion overlapping with at least one of the sensors 201a and 203a.

[0083] The insulating film 245 prevents impurities contained in the colored film 241, the light-shielding film 243, etc. from diffusing into the liquid crystal 249. The insulating film 245 preferably has a function as an overcoat to prevent unwanted It does not have to be provided if necessary.

[0084] An alignment film may be provided in contact with the liquid crystal 249. The alignment film is used to adjust the alignment of the liquid crystal 249. For example, in FIG. 1B, an alignment film covering the conductive film 252 can be formed. In addition, in FIG. 1B, an alignment film may be formed between the insulating film 245 and the liquid crystal 249. The insulating film 245 may have a function as an alignment film and an overcoat. It may have both functions.

[0085] The input / output device 300 also includes a spacer 247. The spacer 247 is It has the function of preventing the distance to the substrate 261 from becoming closer than a certain value.

[0086] In FIG. 1B, the spacer 247 is provided on the insulating film 253 and the conductive film 252. However, one embodiment of the present invention is not limited to this example. For example, the insulating film 245 may be provided on the substrate 261 side. A spacer 247 may be formed on the insulating layer 247. 253 and the insulating film 245, either the substrate 211 side or the substrate 261 side. It does not have to be in contact with any structure installed inside.

[0087] Granular spacers may be used as the spacers 247. For the granular spacers, silica However, it is preferable to use elastic materials such as resin and rubber. At this time, the granular spacers may be crushed in the vertical direction.

[0088] The substrate 211 and the substrate 261 are bonded together by an adhesive layer 265. A liquid crystal 249 is sealed in the area surrounded by the substrate 261 and the adhesive layer 265 .

[0089] When the input / output device 300 is made to function as a transmissive liquid crystal display device, the polarizing plate is The light from the backlight placed outside the polarizing plate is At this time, the voltage applied between the conductive film 251 and the conductive film 252 is Therefore, the orientation of the liquid crystal 249 can be controlled, and the optical modulation of light can be controlled. The intensity of the light emitted through the light plate can be controlled. Since light outside of a specific wavelength range is absorbed by the Or the light will be green.

[0090] In addition to the polarizing plate, for example, a circular polarizing plate can be used. For example, a laminate of a linear polarizer and a quarter-wave retardation plate can be used. This reduces the viewing angle dependency of the display of the input / output device.

[0091] In this example, an element to which the FFS mode is applied is used as the liquid crystal element 207a. Liquid crystal elements that are not limited to VA (V Vertical Alignment mode, TN (Twisted Nematic) ) mode, IPS (In-Plane-Switching) mode, ASM (Axia (Symmetric aligned Micro-cell) mode, OCB (Optically Compensated Birefringence) mode , FLC (Ferroelectric Liquid Crystal) mode, AF LC (AntiFerroelectric Liquid Crystal) mode, etc. A liquid crystal element to which the above is applied can be used.

[0092] Furthermore, the input / output device 300 may be a normally black type liquid crystal display device, for example, a vertical alignment (VA) A transmissive liquid crystal display device employing a vertical alignment mode may be used. MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, ASV Modes, etc. can be used.

[0093] The liquid crystal element is an element that controls the transmission or non-transmission of light by the optical modulation action of the liquid crystal. The optical modulation effect of the liquid crystal is determined by the electric field (horizontal electric field, vertical electric field or The liquid crystal used in the liquid crystal element is Thermotropic liquid crystal, low molecular weight liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal (PDLC:Pol ymer Dispersed Liquid Crystal), ferroelectric liquid crystal, antiferroelectric Dielectric liquid crystals can be used. These liquid crystal materials can be cholesteric depending on the conditions. phase, smectic phase, cubic phase, chiral nematic phase, isotropic phase, etc.

[0094] In addition, either a positive type liquid crystal or a negative type liquid crystal may be used as the liquid crystal material, depending on the application. The optimum liquid crystal material can be used depending on the mode and design.

[0095] When the in-plane switching system is adopted, a liquid crystal that exhibits a blue phase without using an alignment film may be used. The blue phase is one of the liquid crystal phases, and when the temperature of cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the crystalline phase to the isotropic phase. In order to improve the temperature range, a liquid crystal composition containing 5% by weight or more of a chiral agent is used. The liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent is used as the liquid crystal 249. The speed is short and the liquid crystal is optically isotropic. Also, the liquid crystal exhibits a blue phase and contains a chiral agent. The composition does not require alignment treatment and has little viewing angle dependency. Since the rubbing process is unnecessary, electrostatic damage caused by the rubbing process is prevented. This can prevent defects or damage to the liquid crystal display device during the manufacturing process. .

[0096] Here, above the substrate 261, there is a substrate that is directly touched by a detection object such as a finger or a stylus. In this case, a polarizing plate or a circular polarizing plate may be provided between the substrate 261 and the substrate. In this case, it is preferable to provide a protective layer (ceramic coating, etc.) on the substrate. The protective layer is preferably made of, for example, silicon oxide, aluminum oxide, yttrium oxide, or yttrium oxide. Inorganic insulating materials such as yttria-stabilized zirconia (YSZ) can be used. The substrate may be made of tempered glass. The tempered glass is made by an ion exchange method, an air-cooling tempering method, or the like. It is possible to use materials that have been subjected to physical or chemical treatment and have had compressive stress applied to their surfaces. Cut.

[0097] FIG. 2(A) shows a cross-sectional view of two adjacent pixels. The pixels are sub-pixels that different pixels have.

[0098] In the input / output device shown in FIG. 2A, the conductive film 252 of the left subpixel and the conductive film 253 of the right subpixel are The capacitance formed between the conductive film 252 and the object to be detected is utilized to detect the proximity or contact of the object to be detected. That is, in the input / output device of one embodiment of the present invention, the conductive film 252 can be It serves as both a common electrode for the crystal element and an electrode for the detection element.

[0099] In this manner, in the input / output device of one embodiment of the present invention, the electrode constituting the liquid crystal element is Since the electrode also serves as a constituent electrode, the manufacturing process can be simplified and manufacturing costs can be reduced. This allows the input / output device to be made thinner and lighter.

[0100] The conductive film 252 is electrically connected to a conductive film 255 that functions as an auxiliary wiring. By providing the film 255, the resistance of the electrodes of the sensing element can be reduced. The reduction in the resistance of the electrodes can reduce the time constant of the electrodes of the detection element. The smaller the time constant of the element electrodes, the higher the detection sensitivity and, further, the higher the detection accuracy. can be increased.

[0101] In addition, if the capacitance between the electrode of the detection element and the signal line is too large, the time constant of the electrode of the detection element will Therefore, a planarization function is provided between the transistor and the electrode of the detector element. It is preferable to provide an insulating film having the following structure to reduce the capacitance between the electrode of the sensing element and the signal line. For example, in FIG. 2A, an insulating film 219 is provided as an insulating film having a planarizing function. By providing the insulating film 219, the capacitance between the conductive film 252 and the signal line can be reduced. This reduces the time constant of the electrodes of the sensing element. The smaller the time constant of the electrode, the higher the detection sensitivity and, further, the higher the detection accuracy. It can be done.

[0102] For example, the time constant of the electrodes of the sensing element is greater than 0 seconds and is 1×10 -4 seconds or less, preferably 0 5 x 10 seconds or more -5 seconds or less, more preferably greater than 0 seconds and 5×10 -6 seconds or less, More preferably, it is greater than 0 seconds and 5×10 -7 seconds or less, more preferably greater than 0 seconds and 2× 10 -7 It is preferable that the time constant is 1×10 seconds or less.-6 By setting the time to less than 2 seconds, noise Therefore, high detection sensitivity can be achieved while suppressing the influence of the above.

[0103] [Example of cross-sectional configuration of input / output device 2] FIG. 2(B) shows a cross-sectional view of two adjacent pixels, which is different from FIG. 2(A). The two sub-pixels shown in FIG. 1 are sub-pixels that different pixels have. The cross-sectional views between the dashed dotted lines AB and CD in (A) are shown in FIG. 3(A).

[0104] The second structural example shown in FIGS. 2B and 3A includes a conductive film 251, a conductive film 252, an insulating film 25 3 and the conductive film 255 are stacked in a different order from that in the first structural example shown in FIGS. 1B and 2A. In addition, in the configuration example 2, the same parts as in the configuration example 1 can be referred to above. do.

[0105] Specifically, in the second configuration example, a conductive film 255 is provided over the insulating film 219. The conductive film 252 has an insulating film 253 thereon, and the conductive film 251 has an insulating film 253 thereon. It has.

[0106] As shown in FIG. 2B, the liquid crystal element 207b is provided in the upper layer and has a comb-like or slit-like The conductive film 251 having a top surface shape is used as a pixel electrode, and the conductive film 252 provided in the lower layer is used as a common electrode. The conductive film 251 can also be used as a source or drain of the transistor 203a. The power supply is electrically connected to the power supply.

[0107] In FIG. 2B, the conductive film 252 of the left subpixel and the conductive film 252 of the right subpixel are By utilizing the capacitance formed between the sensor and the object, it is possible to detect the proximity or contact of the object to be detected. That is, in the input / output device of one embodiment of the present invention, the conductive film 252 is a common electrode of a liquid crystal element. and serves as both an electrode of the detection element.

[0108] In the configuration example 1 (Fig. 1(B) and Fig. 2(A)), the conductive layer serves as both the electrode of the sensing element and the common electrode. The conductive film 252 is closer to the display surface side (the side closer to the object to be detected) than the conductive film 251 that functions as a pixel electrode. ) is located. This results in a configuration in which the conductive film 251 is located closer to the display surface than the conductive film 252. In the configuration example 1, the detection sensitivity may be improved compared to the example 2.

[0109] In addition, in the configuration example 2, the multilayer structure of the conductive film 251, the conductive film 252, the insulating film 253, and the conductive film 255 is Since the layer order is different from that of Configuration Example 1, the configuration of the connection portion is also different from that of Configuration Example 1.

[0110] The connection portion 205b shown in FIG. 3A has a conductive film 231 over the insulating film 213. A conductive film 233 is provided on the conductive film 231, and a conductive film 235 is provided on the conductive film 233. The conductive film 252 of the liquid crystal element 207b can be formed using the same material and process. The conductive film 235 is formed using the same material and process as the conductive film 251 of the liquid crystal element 207b. It can be formed by

[0111] Further, another structural example of a transistor included in the input / output device of one embodiment of the present invention is shown in FIG. As shown in Figure 3(B), in a transistor with two gates, In this case, the two gates may not be electrically connected. In this way, at least one of the driving circuit section and the display section is provided with a top-gate transistor. may have

[0112] Another structural example of a liquid crystal element included in an input / output device of one embodiment of the present invention is shown in FIG. 1 to 3F. Both the conductive film 251 and the conductive film 252 have a comb-like top surface shape (plan view). The upper surface may have a rectangular shape, or a slit-like shape.

[0113] For example, when viewed from above, the edge of the slit in one conductive film and the edge of the slit in the other conductive film The cross section of this case is shown in Figure 3(D).

[0114] Alternatively, when viewed from above, a portion where neither the conductive film 251 nor the conductive film 252 is provided may be formed. A cross-sectional view of this case is shown in FIG.

[0115] Alternatively, when viewed from above, the conductive film 251 and the conductive film 252 have a portion where they overlap each other. The cross section of this case is shown in Figure 3(F).

[0116] [Example 3 of cross-sectional configuration of input / output device] FIG. 4 shows a diagram of the area between the dashed dotted lines AB and AB in FIG. 1(A), which is different from FIG. 1(B) and FIG. 3(A). 1 and a cross-sectional view between dashed dotted lines CD.

[0117] In the third example of the configuration shown in FIG. 4, a transistor included in a display portion 301 and a scanning line driver circuit 302 are The structures of the transistors are different from those of Structure Example 1 shown in FIGS. 1B and 2A. In addition, in the configuration example 3, for the same parts as the configuration example 1, please refer to the above. can be done.

[0118] The transistor 201b has an oxide semiconductor film in which a channel is formed sandwiched between two gates. In the transistor 201b, the gate electrode 221 and the oxide conductive film 227 are directly connected to each other. The difference from transistor 201a is that the two gates are in contact with each other. The electrical connection may be made without an intervening wire.

[0119] The transistor 203b is similar to the transistor 201b in that the oxide in which the channel is formed is The semiconductor film 223 is sandwiched between two gates. In addition, a transistor having two gates can also be applied to the display portion. Although not shown, the gate electrode 221 and the oxide conductive film 227 are also formed in the transistor 203b. are preferably electrically connected.

[0120] The closer the distance between the oxide conductive film 227 and the electrode of the detection element, the This can easily cause a problem in which the potential of the electrode of the detection element changes. In this embodiment, the oxide conductive film 227 and the electrodes of the detection element are provided in different layers. This electrode is less susceptible to the influence of the oxide conductive film 227 and is therefore preferable.

[0121] [Example 4 of cross-sectional configuration of input / output device] 5, which is different from FIGS. 1(B), 3(A), and 4, the dashed line A in FIG. 1(A) is -B and dashed line CD are cross-sectional views.

[0122] The fourth example of the configuration shown in FIG. 5 is a configuration of the transistors included in the scanning line driver circuit 302 and a configuration of the spacer The substrate on which the 247 is provided is different from that in the configuration example 1 shown in FIG. 1(B) and FIG. 2(A). In the configuration example 4, the same parts as those in the configuration example 1 can be referred to above. .

[0123] The transistor 201c has an oxide semiconductor film in which a channel is formed sandwiched between two gates. The transistor 201c has a structure in which the oxide conductive film 227 is formed at a position corresponding to the Specifically, the insulating film 217 is provided on the insulating film 215. An insulating film 218 having a planarizing function is formed on the insulating film 218. In this way, the oxide conductive film 227 is provided on an insulating film having a planarizing function. The transistor 201c may be covered with an insulating film 219 having a planarization function. In FIG. 5, the oxide conductive film 227 is electrically connected to the gate electrode 221 via the conductive film 226. 4, the oxide conductive film 227 and the gate electrode 228 are electrically connected. The poles 221 may be directly connected.

[0124] 5 shows an example in which a spacer 247 is provided on the insulating film 245. As shown, a spacer 247 may be disposed on the substrate 261 side.

[0125] [Example 5 of cross-sectional configuration of input / output device] FIG. 6 shows a point in FIG. 1(A) that is different from those in FIGS. 1(B), 3(A), 4, and 5. 1 shows a cross-sectional view between chain line AB and dashed line CD.

[0126] In the configuration example 5 shown in FIG. 6, the formation position of the colored film 241 is different from that of the configurations shown in FIGS. 1(B) and 2(A). Configuration Example 5 differs from Configuration Example 1. For the same parts of Configuration Example 5 as those of Configuration Example 1, please refer to the above. It can be illuminated.

[0127] The colored film 241 is not limited to being formed on the opposing substrate (substrate 261). As shown, the semiconductor device may be formed on the substrate 211 on which the transistors and the like are formed. As the resolution of the display of the power device increases, the alignment accuracy between the substrate 211 and the substrate 261 decreases. This can prevent a decrease in yield and a decrease in display quality.

[0128] [Example 6 of cross-sectional configuration of input / output device] 34 shows a cross-sectional view of an input / output device different from the above-described configuration examples. The device is configured such that electrodes constituting the detection element are provided only on the substrate supporting the display element (full The touch panel is not limited to the in-cell type. An electrode constituting a detection element may be provided on the side.

[0129] In FIG. 34, a conductive film is formed on the surface of the substrate 261 opposite to the surface on which the colored film 241 and the like are formed. The conductive film 254 is connected to the FPC 2 via a connector 257. 34, the conductive film 252 and the The capacitance formed between the conductive film 254 is used to detect the proximity or contact of an object to be detected. That is, in the input / output device of one embodiment of the present invention, the conductive film 252 can The common electrode of the liquid crystal element and one of the electrodes of the detection element are both used. The conducting electrode may also serve as one electrode of the detection element, or may also serve as a pair of electrodes of the detection element. It's fine.

[0130] 34 shows an example in which a conductive film 255 is provided over the conductive film 252. The conductive film that can function as an auxiliary wiring for the electrode may be on either side. stomach.

[0131] Next, details of materials that can be used for each component of the input / output device of this embodiment will be described. The explanation will be given below. Note that the explanation of components that have already been explained may be omitted. In addition, the following materials may be used appropriately for the input / output device and its components shown in the following embodiments. This can be done.

[0132] <Substrate> There is no particular restriction on the material of the substrate of the input / output device 300, but at least the material of the substrate should be selected for the subsequent heat treatment. For example, glass substrates and ceramic substrates are A substrate made of silicon or silicon carbide may also be used. single crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, It is also possible to use an SOI substrate, etc., and a semiconductor element is provided on such a substrate. In addition, when a glass substrate is used as the substrate, the sixth generation (1500mm x 1850mm), 7th generation (1870mm x 2200mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 2800mm), 10th generation By using large area substrates such as (2950mm x 3400mm), it is possible to create large display devices. Alternatively, a flexible substrate may be used as the substrate 211, and the substrate may be directly formed on the flexible substrate. A transistor, a capacitor, or the like may be formed.

[0133] By using a thin substrate, the input / output device can be made lighter and thinner. By using a substrate thick enough to be flexible, a flexible input / output device can be realized. can.

[0134] In addition to these, various substrates can be used as the substrates 211 and 261 to form transistors. The type of substrate is not limited to a specific one. Examples include plastic substrates, metal substrates, stainless steel substrates, and stainless steel substrates. Substrate with foil, tungsten substrate, substrate with tungsten foil, flexible These include substrates, laminated films, papers containing fibrous materials, or base films. Examples of the glass substrate include barium borosilicate glass, aluminoborosilicate glass, or silicon dioxide. An example of a flexible substrate is polyethylene terephthalate. (PET), polyethylene naphthalate (PEN), polyethersulfone (PES) Examples include plastics such as acrylic, and flexible synthetic resins. Examples of laminated films include polypropylene, polyester, polyvinyl fluoride, and Examples of the base film include polyester and polyamide. , polyimide, inorganic vapor deposition film, paper, etc. In particular, semiconductor substrates, single crystal substrates By manufacturing transistors using a silicon-on-insulator (SOI) substrate, the characteristics, size, is used to manufacture small-sized transistors with little variation in shape, high current capacity, etc. When a circuit is constructed using such transistors, the circuit consumes less power. This allows for a higher integration of the circuit.

[0135] Note that a transistor is formed using a certain substrate and then transferred to another substrate. However, the transistor may be disposed on another substrate. As the substrate, in addition to the substrate on which the above-mentioned transistor can be formed, a paper substrate, a cellophane substrate, etc. substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, linen), synthetic fibers (nylon, Polyurethane, polyester) or recycled fiber (acetate, cupra, rayon, recycled These substrates include raw polyester, leather substrates, and rubber substrates. This allows for the formation of transistors with good characteristics and low power consumption. This allows for the manufacture of devices that are less likely to break, more heat resistant, lighter in weight, or thinner.

[0136] <Transistor> The structure of a transistor included in an input / output device of one embodiment of the present invention is not particularly limited. The transistors may be planar type, staggered type, or inversely. A staggered transistor may be used. Also, either a top gate type or a bottom gate type may be used. Alternatively, a gate electrode may be provided above and below the channel. The semiconductor material used for the transistor is not particularly limited, and may be, for example, an oxide semiconductor. , silicon, germanium, etc.

[0137] The crystallinity of the semiconductor material used in the transistor is not particularly limited. A semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or a semiconductor having a partially crystalline region) When a semiconductor having crystallinity is used, the transistor This is preferable because it can suppress deterioration of the star characteristics.

[0138] Semiconductor materials used in transistors include, for example, elements of Group 14, compound semiconductors, A silicon or oxide semiconductor can be used for the semiconductor layer. A semiconductor containing gallium arsenide, an oxide semiconductor containing indium, or the like can be used.

[0139] In particular, it is preferable to use an oxide semiconductor as a semiconductor in which a channel of a transistor is formed. It is particularly preferable to use an oxide semiconductor having a larger band gap than silicon. It is desirable to use a semiconductor material with a wider band gap and lower carrier density than silicon. This is preferable because it can reduce the current in the off state of the transistor.

[0140] For example, the oxide semiconductor may contain at least indium (In) or zinc (Zn). More preferably, the oxide contains In-M-Zn (wherein M is Al, Ti, Ga). , Ge, Y, Zr, La, Ce, Sn, Mg, Nd, or Hf (metals such as Contains compounds.

[0141] In particular, the semiconductor layer has a plurality of crystal portions, and the c-axes of the crystal portions are aligned with the surface on which the semiconductor layer is formed, Or, the crystals are oriented approximately perpendicular to the upper surface of the semiconductor layer, and there are no grain boundaries between adjacent crystal portions. An oxide semiconductor film is preferably used.

[0142] Such an oxide semiconductor does not have a crystal grain boundary, and therefore, when the display panel is bent, it does not bend. Therefore, cracks are prevented from occurring in the oxide semiconductor film due to the applied force. Such oxide semiconductors are suitable for use in flexible input / output devices that are used in a curved state. It is possible.

[0143] Furthermore, by using such an oxide semiconductor as the semiconductor layer, fluctuations in electrical characteristics are suppressed. This makes it possible to realize a highly reliable transistor.

[0144] In addition, due to its low off-state current, the charge stored in the capacitor can be released over a long period of time via the transistor. By applying such a transistor to the pixel, It is also possible to stop the driving circuit while maintaining the gradation of the image displayed in the display area. As a result, a display device with extremely reduced power consumption can be realized.

[0145] <Oxide semiconductor film> The oxide semiconductor film 223 contains at least indium (In), zinc (Zn), and M (Al, metals such as Ti, Ga, Ge, Y, Zr, La, Ce, Sn, Mg, Nd, or Hf) It is preferable that the oxide semiconductor includes a film represented by In-M-Zn oxide. To reduce the variation in the electrical characteristics of the transistors used, stabilizers are also used. It is preferred that the compound contains:

[0146] The stabilizer includes the metals described above under M, such as gallium (Ga) and tin. (Sn), hafnium (Hf), aluminum (Al), or zirconium (Zr), etc. Other stabilizers include lanthanides such as lanthanum (La) and cerium (Ce). Ce, Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Rhodium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy ), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Y b), lutetium (Lu), etc.

[0147] The oxide semiconductor constituting the oxide semiconductor film 223 is, for example, an In-Ga-Zn oxide. In-Al-Zn oxides, In-Sn-Zn oxides, In-Hf-Zn oxides , In-La-Zn oxide, In-Ce-Zn oxide, In-Pr-Zn oxide, In-Nd-Zn oxide, In-Sm-Zn oxide, In-Eu-Zn oxide, I n-Gd-Zn oxide, In-Tb-Zn oxide, In-Dy-Zn oxide, In -Ho-Zn oxide, In-Er-Zn oxide, In-Tm-Zn oxide, In- Yb-Zn oxide, In-Lu-Zn ​​oxide, In-Sn-Ga-Zn oxide, I n-Hf-Ga-Zn oxide, In-Al-Ga-Zn oxide, In-Sn-Al- Zn-based oxide, In-Sn-Hf-Zn-based oxide, In-Hf-Al-Zn-based oxide are used. You can be there.

[0148] Here, the In-Ga-Zn oxide is a material containing In, Ga, and Zn as main components. It means oxide, and the ratio of In, Ga, and Zn does not matter. Other metal elements may also be included.

[0149] When the oxide semiconductor film 223 is an In-M-Zn oxide, the sum of In and M is 10 When the atomic percentage is 0, preferably In is higher than 25 atomic percent and M is 75 atomic %, more preferably In is higher than 34 atomic %, and M is 66 atomic %. less than 0.05%.

[0150] The oxide semiconductor film 223 has an energy gap of 2 eV or more, preferably 2.5 eV or more. More preferably, it is 3 eV or more. By using the body, the off-state current of a transistor can be reduced.

[0151] The thickness of the oxide semiconductor film 223 is 3 nm to 200 nm, preferably 3 nm to 100 nm. 0 nm or less, and more preferably 3 nm or more and 50 nm or less.

[0152] The oxide semiconductor film 223 is an In-M-Zn oxide (M is Al, Ti, Ga, Ge, Y, Zr , La, Ce, Sn, Mg, Nd, or Hf), an In-M-Zn oxide is formed. The atomic ratio of the metal elements in the sputtering target used for this purpose is In≧M, Zn≧M. It is preferable that the atomic ratio of the metal elements in such a sputtering target is In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn= 3:1:2, In:M:Zn=1:3:4, In:M:Zn=1:3:6, etc. The atomic ratio of the oxide semiconductor film 223 to be formed is determined by the above-mentioned sputtering method. The atomic ratio of the metal elements contained in the target varies by ±40%. nothing.

[0153] As the oxide semiconductor film 223, an oxide semiconductor film with low carrier density is used. For example, The oxide semiconductor film 223 has a carrier density of 1×10 17 pieces / cm 3 Below, preferably 1x 10 15 pieces / cm 3 or less, more preferably 1 × 10 13 pieces / cm 3 The following is more preferable: is 1 x 10 11 pieces / cm 3 The following oxide semiconductor film is used.

[0154] In addition, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. An appropriate composition can be used depending on the required properties (mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of the transistor, the carrier density of the oxide semiconductor film 223 and The impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. are appropriately determined. It is preferable to do so.

[0155] The oxide semiconductor film 223 contains silicon or carbon, which is one of Group 14 elements. As a result, oxygen vacancies increase in the oxide semiconductor film 223, causing the oxide semiconductor film 223 to become n-type. The concentration of silicon and carbon in the semiconductor film 223 was measured by secondary ion mass spectrometry (SIMS). Concentration obtained by secondary ion mass spectrometry ) to 2 x 10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0156] In addition, in the oxide semiconductor film 223, an alkali metal or alkali metal oxide obtained by SIMS The concentration of alkali earth metals is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 a toms / cm 3 Alkali metals and alkaline earth metals bond with oxide semiconductors. When the transistor is mixed with the SiO2, carriers may be generated, increasing the off-state current of the transistor. Therefore, the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor film 223 is It is preferable to reduce it.

[0157] When nitrogen is contained in the oxide semiconductor film 223, electrons serving as carriers are generated. As a result, the nitride semiconductor containing nitrogen is used. Therefore, the transistor having the oxide semiconductor film tends to be normally on. Therefore, it is preferable that the nitrogen content is reduced as much as possible. For example, The nitrogen concentration is 5 x 10 18atoms / cm 3 It is preferable to do the following:

[0158] The oxide semiconductor film 223 may have a non-single-crystal structure, for example. , CAAC-OS (C Axis Aligned-Crystalline Oxide Semiconductor), polycrystalline structure, microcrystalline structure (described later), or non-crystalline Among non-single crystalline structures, the amorphous structure has the highest defect level density and CAA C-OS has the lowest density of defect states.

[0159] The oxide semiconductor film 223 may have, for example, an amorphous structure. For example, the atomic arrangement is disordered and does not have crystalline components. Alternatively, the oxide film has an amorphous structure. For example, the amorphous structure of the crystalline silicon film is completely amorphous and does not have any crystalline portions.

[0160] Note that the oxide semiconductor film 223 may have an amorphous structure, a microcrystalline structure, or a polycrystalline structure. The film may be a mixed film having two or more of the following: a CAAC-OS region, a single crystal structure region, and a single crystal structure region. The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CAA region, or the like. In the case of a single-layer structure having two or more regions, either a C-OS region or a single-crystal structure region, The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, and a polycrystalline structure region. The layer structure has two or more types of regions, namely, a CAAC-OS region, a single crystal structure region, and a This may occur.

[0161] Alternatively, it is preferable to use silicon as a semiconductor in which a channel of a transistor is formed. Although amorphous silicon may be used as silicon, silicon having crystallinity is particularly preferred. For example, microcrystalline silicon, polycrystalline silicon, and single crystal silicon are preferably used. In particular, polycrystalline silicon can be used at a lower temperature than single-crystal silicon. It can be formed and has higher field effect mobility and higher reliability than amorphous silicon. By applying such polycrystalline semiconductor to pixels, the aperture ratio of the pixels can be improved. Even when manufacturing an extremely high-resolution input / output device, the gate driver circuit and the source driver It is now possible to form circuits and pixels on the same substrate, reducing the number of components that make up electronic devices. It is possible.

[0162] <Method for controlling the resistivity of an oxide semiconductor> Oxide semiconductors have resistance due to oxygen vacancies in the film and / or the concentration of impurities such as hydrogen and water in the film. Therefore, the oxide semiconductor film is formed by adding oxygen vacancies or and / or impurity concentration increases, or oxygen deficiency and / or impurity concentration decreases. By selecting the material, the resistivity of the oxide conductive film can be controlled.

[0163] Note that the oxide conductive film formed using the oxide semiconductor film has a carrier density a high-resistance and low-resistance oxide semiconductor film, a conductive oxide semiconductor film, or a highly conductive oxide semiconductor film; It can also be called a semiconductor film.

[0164] Specifically, the oxide semiconductor film to be the oxide conductive film 227 functioning as a gate is heated by plasma. The oxide semiconductor film is subjected to a treatment to increase oxygen vacancies and / or By increasing impurities such as hydrogen and water, oxide semiconductors with high carrier density and low resistance can be obtained. The insulating film 217 containing hydrogen can be formed in contact with the oxide semiconductor film. By diffusing hydrogen from the insulating film 217 containing hydrogen into the oxide semiconductor film, An oxide semiconductor film with high carrier density and low resistance can be obtained.

[0165] On the other hand, on the oxide semiconductor film 223, the oxide semiconductor film 223 is exposed to the plasma treatment. In order to prevent this, the insulating film 215 is provided. The semiconductor film 223 is not in contact with the insulating film 217 containing hydrogen. By using an insulating film capable of releasing oxygen, oxygen can be supplied to the oxide semiconductor film 223. The oxide semiconductor film 223 to which oxygen is supplied can be filled with oxygen vacancies in the film or at the interface. The insulating film capable of releasing oxygen is an oxide semiconductor having a high resistance. For example, a silicon oxide film or a silicon oxynitride film can be used.

[0166] In order to obtain an oxide semiconductor film with low resistivity, an ion implantation method, an ion doping method, Using plasma immersion ion implantation, hydrogen, boron, phosphorus Alternatively, nitrogen may be implanted into the oxide semiconductor film.

[0167] The oxide conductive film 227 is typically subjected to plasma treatment using a rare gas (He, N e, Ar, Kr, Xe), phosphorus, boron, hydrogen, and gas containing one selected from nitrogen More specifically, plasma treatment under an Ar atmosphere is one example. , plasma treatment under a mixed gas atmosphere of Ar and hydrogen, plasma treatment under an ammonia atmosphere plasma treatment in a mixed gas atmosphere of Ar and ammonia, or plasma treatment in a nitrogen atmosphere. Examples include Zuma processing.

[0168] By the plasma treatment, the oxide conductive film 227 becomes a lattice from which oxygen has been desorbed (or Oxygen vacancies are formed in the separated areas. These oxygen vacancies are a cause of carrier generation. In addition, in the vicinity of the oxide conductive film 227, more specifically, in the vicinity of the oxide conductive film 22 When hydrogen is supplied from the insulating film in contact with the upper or lower side of 7 and enters the oxygen vacancy, Therefore, oxygen vacancies caused by plasma treatment may be reduced by generating electrons, which are carriers. The increased oxide conductive film 227 has a higher carrier density than the oxide semiconductor film 223.

[0169] On the other hand, the oxide semiconductor film 223 in which oxygen vacancies are reduced and the hydrogen concentration is reduced is a highly purified intrinsic oxide semiconductor film. The substantially intrinsic oxide semiconductor film can be referred to as a highly purified or substantially intrinsic oxide semiconductor film. indicates that the carrier density of the oxide semiconductor is 1×10 17 / cm 3 preferably less than 1×10 15 / cm 3 more preferably less than 1×10 13 / cm 3 Less than Or, it means that the impurity concentration is low and the defect level density is low (few oxygen vacancies). High purity authentic or substantially high purity authentic. Since oxide semiconductors have few carrier generation sources, the carrier density can be reduced. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film has a threshold voltage The electrical characteristics tend to be such that the voltage becomes positive (also called normally-off characteristics). The highly intrinsic or substantially highly purified intrinsic oxide semiconductor film 223 has a low density of defect states. Therefore, the trap state density can be reduced.

[0170] In addition, the highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film 223 has a significantly low off-state current. The channel width is 1×10 6 Even if the device has a channel length of 10 μm, When the voltage between the source and drain electrodes (drain voltage) is in the range of 1V to 10V, The off-current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1×10 -13 Below A Therefore, a channel region is formed in the oxide semiconductor film 223. The transistor thus fabricated has little fluctuation in electrical characteristics and is highly reliable.

[0171] The insulating film 217 may be, for example, an insulating film containing hydrogen, in other words, capable of releasing hydrogen. By using an insulating film, typically a silicon nitride film, hydrogen is supplied to the oxide conductive film 227. The insulating film capable of releasing hydrogen has a hydrogen concentration of 1×1 0 22 atoms / cm 3 It is preferable that the insulating film is the oxide conductive film 22. By forming the oxide conductive film 227 in contact with the oxide conductive film 7, hydrogen can be effectively contained in the oxide conductive film 227. In this way, in addition to the above-described plasma treatment, the oxide semiconductor film (or the oxide conductive film ) by changing the structure of the insulating film in contact with the oxide semiconductor film (or the oxide conductive film). The resistance can be adjusted arbitrarily.

[0172] The hydrogen contained in the oxide conductive film 227 reacts with the oxygen that bonds with the metal atoms to form water. In this case, oxygen vacancies are formed in the lattice from which oxygen has been desorbed (or in the portion from which oxygen has been desorbed). When hydrogen enters the gap, electrons, which act as carriers, are generated. When bonded to oxygen, which bonds to metal atoms, electrons, which act as carriers, may be generated. Therefore, the oxide conductive film 227 containing hydrogen has a higher hydrogen content than the oxide semiconductor film 223. High carrier density.

[0173] The oxide semiconductor film 223 in which the channel region of the transistor is formed has hydrogen reduced as much as possible. Specifically, the oxide semiconductor film 223 is preferably The resulting hydrogen concentration is 2 x 10 20 atoms / cm 3 Less than or equal to 5 x 10 19 atoms / cm 3 Less than or equal to 1×10 19 atoms / cm 3 Below, more preferred Preferably 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 More preferably, 1×10 16 atoms / cm 3 The following applies.

[0174] On the other hand, the oxide conductive film 227 functioning as a gate has a higher hydrogen concentration than the oxide semiconductor film 223. The degree and / or amount of oxygen deficiency is high, resulting in low resistance.

[0175] The oxide conductive film 227 can be formed using a material that can be used for the oxide semiconductor film 223 and an oxide semiconductor. The method for forming the conductive film 223 can be applied. The organic conductive film 227 is translucent.

[0176] Note that a material that can be used for the oxide conductive film 227 and a method for forming the oxide conductive film 227 This method can also be applied to the conductive film 251 and the conductive film 252.

[0177] <Insulating film> Insulating material that can be used for insulating films, overcoats, spacers, etc. in input / output devices As the material, an organic insulating material or an inorganic insulating material can be used. For example, acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyamideimide resin, siloxane resin, benzocyclobutene resin, phenol resin, etc. Examples of the organic insulating film include a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, and a silicon nitride film. Silicon film, aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film um oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, oxide Examples include a cerium film and a neodymium oxide film.

[0178] <Conductive film> In addition to the gate, source, and drain of a transistor, various wirings and electrodes of an input / output device Conductive films such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, etc. Metals such as tungsten, molybdenum, silver, tantalum, or tungsten, or those containing these as the main component The alloy can be used as a single layer structure or a laminated structure. For example, a two-layer structure in which a titanium film is laminated on a tungsten film; a two-layer structure in which a titanium film is laminated on a tungsten film; Two-layer structure with copper film laminated on molybdenum film, copper film on alloy film containing molybdenum and tungsten a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film; The titanium film or titanium nitride film is laminated with an aluminum film. a three-layer structure in which a titanium film or a titanium nitride film is formed on top of a titanium or copper film; A molybdenum film or a molybdenum nitride film and a layer of a metal film overlaid on the molybdenum film or the molybdenum nitride film. An aluminum film or a copper film is laminated on the aluminum film, and a molybdenum film or a molybdenum nitride film is further laminated on the aluminum film or a copper film. For example, a three-layer structure is formed by forming a source electrode 225a and a drain electrode 225b. In the case of a three-layer structure, the first and third layers are made of titanium, titanium nitride, molybdenum, and tungsten. Alloys containing molybdenum and tungsten, alloys containing molybdenum and zirconium, or a film made of molybdenum nitride is formed, and the second layer is made of copper, aluminum, gold, or silver, or It is preferable to form a film made of a low resistance material such as an alloy of copper and manganese. Indium tin oxide, indium oxide with tungsten oxide, indium oxide with tungsten oxide Indium zinc oxide, indium oxide with titanium oxide, indium tin oxide with titanium oxide Translucent oxides, such as indium zinc oxide and silicon oxide-doped indium tin oxide A conductive material having the following structure may be used.

[0179] Note that the conductive film may be formed by using the above-described method for controlling the resistivity of an oxide semiconductor.

[0180] ≪Adhesive layer≫ The adhesive layer 265 may be made of a curable resin such as a thermosetting resin, a photocurable resin, or a two-liquid mixed curable resin. Resins can be used, such as acrylic resins, urethane resins, epoxy resins, or Resins having siloxane bonds can be used.

[0181] <Connector> The connector may be, for example, an anisotropic conductive film (ACF). Conductive Film) or Anisotropic Conductive Paste (ACP) c Conductive Paste) can be used.

[0182] ≪Colored film≫ The colored film is a colored layer that transmits light in a specific wavelength range. Materials that can be used for the colored film Examples of the material include metal materials, resin materials, and resin materials containing pigments or dyes.

[0183] <Light-shielding film> The light-shielding film is provided between the adjacent colored films. The light-shielding film may be made of, for example, a metal material, The black matrix can be formed using a resin material containing a pigment or a dye. If the light-shielding film is provided in areas other than the display area, such as the drive circuit area, unintended light caused by guided light or the like can be prevented. This is preferable because it can suppress unwanted light leakage.

[0184] [Example of how input / output devices work] Next, an example of a method for operating the input / output device of one embodiment of the present invention will be described.

[0185] FIG. 7A illustrates a part of a pixel circuit provided in a display portion of an input / output device of one embodiment of the present invention. FIG. 1 is an equivalent circuit diagram.

[0186] One pixel has at least a transistor 3503 and a liquid crystal element 3504. The gate of the transistor 3503 is electrically connected to a wiring 3501. A wiring 3502 is electrically connected to one of the source and drain of the transistor 3503 .

[0187] The pixel circuit includes a plurality of wirings (for example, wiring 3510_1, wiring 3510_2, wiring 3510_3, wiring 3510_4, wiring 3510_5, wiring 3510_6, wiring 3510_7, wiring 3510_8, wiring 3510_9, wiring 3510_10, wiring 3510_11, wiring 3510_12, wiring 3 2) and a plurality of wirings (for example, wiring 3511_1) extending in the Y direction, which are mutually The electrodes are arranged to intersect with each other, forming a capacitance therebetween.

[0188] In addition, among the pixels provided in the pixel circuit, some adjacent pixels are provided with The electrodes of the liquid crystal elements are electrically connected to each other to form one block. The blocks are divided into island-like blocks (e.g., block 3515_1, block 3515_2) and Linear blocks extending in the X or Y direction (for example, blocks 3 extending in the Y direction) 516). Note that FIG. 7(A) shows only a part of the pixel circuit. However, in reality, these two types of blocks are repeatedly arranged in the X and Y directions. Here, one electrode of the liquid crystal element may be, for example, a common electrode. The other electrode of the element may be, for example, a pixel electrode.

[0189] The wiring 3510_1 (or 3510_2) extending in the X direction is connected to an island-shaped block 3515_ 1 (or block 3515_2). Although not shown, in the X direction, The extending wiring 3510_1 is arranged discontinuously along the X direction via linear blocks. The island-shaped blocks 3515_1 are electrically connected to each other. The wiring 3511_1 is electrically connected to a linear block 3516.

[0190] FIG. 7B shows a plurality of wirings (wirings 3510_1 to 3510_6, collectively referred to as wiring 3510), and a plurality of wirings extending in the Y direction (wirings 3511_1 to This is an equivalent circuit diagram showing the connection configuration of the wiring 3511_6 (also collectively referred to as wiring 3511). Each of the wirings 3510 extending in the X direction and each of the wirings 3511 extending in the Y direction A common potential can be input to each of the wirings 3510 extending in the X direction. A pulse voltage can be input from the pulse voltage output circuit. Each of the wirings 3511 can be electrically connected to a detection circuit. 0 and wiring 3511 can be swapped.

[0191] An example of a method for operating the input / output device of one embodiment of the present invention will be described with reference to FIGS. 8A and 8B. Reveal.

[0192] Here, one frame period is divided into a writing period and a detection period. This is the period in which the image data is written, and the wiring 3501 (also called the gate line or the scanning line) On the other hand, the detection period is a period during which sensing is performed by the detection element. .

[0193] FIG. 8A is an equivalent circuit diagram during the writing period. A common potential is input to both the wiring 3510 extending in the Y direction and the wiring 3511 extending in the Y direction. .

[0194] FIG. 8B is an equivalent circuit diagram during the detection period. During the detection period, the array extending in the Y direction Each of the wires 3511 is electrically connected to a detection circuit. A pulse voltage is input to 0 from the pulse voltage output circuit.

[0195] FIG. 8C is an example of a timing chart of input and output waveforms in a mutual capacitance type sensing element. is.

[0196] In FIG. 8(C), it is assumed that detection of an object is performed in each row and column in one frame period. In Fig. 8(C), the difference between when the object is not detected (non-touch) and when the object is not detected (touched) during the detection period is The figure shows two cases: when detecting (touch) and when detecting (contact).

[0197] The wirings 3510_1 to 3510_6 are supplied with a pulse voltage from a pulse voltage output circuit. A pulse voltage is applied to the wirings 3510_1 to 3510_6. An electric field is generated between the pair of electrodes that form the capacitance, and a current flows through the capacitance. The electric field generated by the sensor changes due to the touch of a finger or pen. This causes a change in the capacitance value of the capacitor. This phenomenon is used to detect the proximity or contact of the object to be detected. You can find out.

[0198] The wirings 3511_1 to 3511_6 are connected to the wirings 3511_1 to 3511_6 by changing the capacitance value of the capacitors. 1 to 3511_6 are connected to a detection circuit for detecting a change in current in the wirings 3511_1 to 3511_6. The lines 3511_1 to 3511_6 detect that there is no proximity or contact of the object to be detected. When there is no change in the current value but the capacitance value decreases due to the proximity or contact of the object to be detected The current value decreases. The current may be detected by detecting the total amount of current. The detection may be performed using an integrating circuit or the like. Alternatively, the peak value of the current may be detected. In this case, the current may be converted into a voltage and the peak value of the voltage may be detected.

[0199] In FIG. 8C, the wirings 3511_1 to 3511_6 are not detected. The waveform shown is a voltage value corresponding to the current value. It is desirable that the timing of the operation and the timing of the detection operation are synchronized.

[0200] In response to the pulse voltages applied to the wirings 3510_1 to 3510_6, the wirings 35 The waveforms on the wirings 11_1 to 3511_6 change. In response to a change in the voltage of the wirings 3510_1 to 3510_6, The waveform of the wiring 3511_6 changes uniformly. Since the current value decreases, the waveform of the corresponding voltage value also changes.

[0201] In this way, by detecting the change in capacitance value, it is possible to detect the proximity or contact of an object to be detected. In addition, the object to be detected, such as a finger or pen, can be detected by approaching the input / output device without touching it. A signal may be detected even if

[0202] In FIG. 8C, the common potential applied to the wiring 3510 during the writing period and Although an example in which the low potentials applied in the detection period are equal is shown, one embodiment of the present invention is not limited thereto. The energizing potential and the lowering potential may be different potentials.

[0203] The pulse voltage output circuit and detection circuit may be formed in a single IC. The IC is preferably mounted in an input / output device or in the housing of an electronic device. In addition, when the input / output device is flexible, it is preferable to mount the device on a flexible substrate. The parasitic capacitance increases at the ridged part, which may increase the effect of noise. It is preferable to use an IC that uses a driving method that is less susceptible to noise. It is preferable to use an IC that employs a driving method that increases the null-to-noise ratio (S / N ratio). .

[0204] In this way, the image writing period and the period in which sensing is performed by the detection element can be performed independently. This prevents the detection element from sensing noise caused by pixel writing. The decrease in the degree of brightness can be suppressed.

[0205] In one embodiment of the present invention, as shown in FIG. 8(D), one frame period includes a writing period and a detection period. Alternatively, as shown in FIG. 8(E), one frame period may have one detection period. By providing multiple detection periods in one frame period, the detection sensitivity can be improved. For example, if one frame period has two to four detection periods, That's fine.

[0206] [Example of top surface configuration of detector element] Next, examples of the top surface configuration of a sensing element included in an input / output device of one embodiment of the present invention will be described with reference to FIGS. 9 to 1. 1 will be used to explain.

[0207] 9A is a top view of the sensing element. The sensing element includes a conductive film 56a and a conductive film 56b. The conductive film 56a functions as one electrode of the sensing element, and the conductive film 56b functions as the other electrode of the sensing element. The sensing element is formed between the conductive film 56a and the conductive film 56b. The capacitance generated can be used to detect the proximity or contact of an object to be detected. The conductive film 56a and the conductive film 56b have a comb-like upper surface shape or an upper surface shape provided with slits. However, they are omitted here.

[0208] In one embodiment of the present invention, the conductive film 56a and the conductive film 56b are used as a common electrode of a liquid crystal element. It also has the function of

[0209] The plurality of conductive films 56a arranged in the Y direction are each provided to extend in the X direction. In addition, the conductive films 56b arranged in the Y direction are connected to the conductive film 58 extending in the Y direction. In FIG. 9A, m conductive films 56a and n conductive films 56b are electrically connected. An example with a membrane 58 is shown.

[0210] In addition, a plurality of conductive films 56a may be arranged in the X direction. In this case, the conductive films 56a extend in the Y direction. Furthermore, the conductive film 58 extending in the X direction may be used to A plurality of conductive films 56b arranged in the same direction may be electrically connected to each other.

[0211] As shown in FIG. 9B, the conductive film 56 that functions as an electrode of the detection element is formed on a plurality of pixels 60. The conductive film 56 is provided over the conductive films 56a and 56b shown in FIG. The pixel 60 is made up of a plurality of sub-pixels each of which exhibits a different color. shows an example in which a pixel 60 is composed of three sub-pixels 60a, 60b, and 60c.

[0212] In addition, a pair of electrodes of the detection element are electrically connected to the auxiliary wiring. In FIG. 10, the conductive film 56a is electrically connected to the auxiliary wiring 57a. In addition, the conductive film 56b is electrically connected to the auxiliary wiring 57b. In the example shown, an auxiliary wiring is provided overlapping on a conductive film. The support member 10 may be provided in a folded state.

[0213] The resistance of the conductive film that transmits visible light may be relatively high. It is preferable to connect the pair of electrodes of the sensing element to each other, thereby reducing the resistance of each of the pair of electrodes of the sensing element. It's nice.

[0214] By reducing the resistance of the pair of electrodes of the detection element, the time constant of each of the pair of electrodes can be reduced. This can improve the detection sensitivity of the detection element and further reduce the This can improve the accuracy of detecting children.

[0215] In the writing period, as shown in FIG. 11(A), the conductive film 56a extending in the X direction and the conductive film 56b extending in the Y direction are The conductive film 58 extending in the direction of the conductor 56b (and the conductive film 56b electrically connected to the conductive film 58) During the detection period, the common potential VCOM is input. On the other hand, as shown in FIG. 11(B), Each of the conductive films 58 (and the conductive film 56b electrically connected to the conductive film 58) extending in the direction The conductive film 56a extending in the X direction is electrically connected to the detection circuit. It is electrically connected to the output circuit and a pulse voltage is input thereto.

[0216] [Example of pixel top surface configuration] Next, examples of top surface structures of pixels included in the input / output device of one embodiment of the present invention are shown in FIGS. 12 to 14. This will be explained using:

[0217] 12 is a top view of a pixel, and FIG. 13 shows the conductive film 252 in FIG. 12 by a dotted line. The stacking order of each layer is the same as that of the cross-sectional structure example 1 (FIG. 1(A) and FIG. 2(A)). You can refer to it.

[0218] The plurality of conductive films 251 each have an island-like upper surface shape and are arranged in a matrix. The conductive film 251 is electrically connected to the source or drain of the transistor 203a. It is being done.

[0219] The conductive film 252 is disposed so as to overlap with a plurality of conductive films 251. The conductive film 252 is formed at a position overlapping with the transistor 203a. The device has an opening at the location.

[0220] Here, the conductive film 251 functions as a pixel electrode of the liquid crystal element, and the conductive film 252 functions as a pixel electrode of the liquid crystal element. 12 and 13, the upper conductive film 252 functions as a common electrode. 251 is a pixel electrode, and the lower conductive film 252 is a pixel electrode. The lower conductive film may be a common electrode.

[0221] The conductive film 252 functions as an electrode of the sensing element.

[0222] In the region 277 indicated by the dashed line, the conductive film 275 and the conductive film 255 are electrically connected. The conductive film 255 functions as an auxiliary wiring for the conductive film 252 and is electrically connected to the conductive film 252. The conductive film 275 is made of the same material as the source and drain of the transistor 203a. , can be formed in the same process.

[0223] The conductive films 252 arranged in the Y direction correspond to the conductive film 56b in FIG. 9(A) and the like. The conductive film 275 extending in the Y direction is the same as the conductive film 58 in FIG. The conductive films 252 arranged in the Y direction correspond to the conductive films 252 extending in the Y direction. The conductive film 252 is electrically connected to the conductive film 275 through the conductive film 255. When an oxide conductive film is used, it is preferable to connect the conductive film 252 and the conductive film 275 directly to each other. The conductive film 255 and the conductive film 275 formed of metal or alloy are connected to each other, and the conductive film 255 is formed therebetween. The contact resistance can be reduced by electrically connecting the conductive film 252 and the conductive film 275. ,preferable.

[0224] 12 and 13 show an example in which the pixel 273 has three sub-pixels. is not limited to this.

[0225] 14A and 14B show examples of the top surface shape of an electrode of a liquid crystal element.

[0226] The pixel electrode and the common electrode of the liquid crystal element 207 are not limited to being flat, but may be formed in various shapes. It may have an opening pattern (also called a slit), or it may have a bent portion or a branched comb-like shape. The shape may include:

[0227] The liquid crystal element 207 shown in FIGS. 14(A) and 14(B) has a conductive layer that can function as a pixel electrode. The pixel includes a conductive film 251 and a conductive film 252 that can function as a common electrode.

[0228] The transistor 203 shown in FIGS. 14A and 14B includes a gate electrode 221, an oxide semiconductor film The conductive film 251 has a source electrode 225a and a drain electrode 225b. It is electrically connected to the rain electrode 225b.

[0229] FIG. 14(A) shows an example in which the conductive film 251 has slits, and FIG. 14(B) shows an example in which the conductive film 14A and 14B show an example in which the film 251 has a shape including a comb-like shape. In the example shown, the conductive film 251 is located above the conductive film 252. It may be located above.

[0230] [Touch panel module] Next, a touch panel module including an input / output device according to one embodiment of the present invention and an IC will be described. This will be explained with reference to FIGS. 15 and 16.

[0231] FIG. 15 shows a block diagram of the touch panel module 6500. The module 6500 includes a touch panel 6510 and an IC 6520. The input / output device of one embodiment of the present invention can be applied to the above.

[0232] The touch panel 6510 includes a display unit 6511, an input unit 6512, and a scanning line driver circuit 651. The display portion 6511 has a plurality of pixels, a plurality of signal lines, and a plurality of scan lines. The input unit 6512 has a function of displaying an image. It has multiple detection elements that detect contact or proximity and functions as a touch sensor. The scan line driver circuit 6513 has a function of outputting scan signals to the scan lines of the display unit 6511. Has.

[0233] For ease of explanation, the touch panel 6510 is configured as a display unit 6511. The input unit 6512 is shown separately, but it has a function to display an image and a function as a touch sensor. It is preferable to use a so-called in-cell type touch panel that has both functions. The input / output device of one embodiment of the present invention is preferable because it is an in-cell touch panel.

[0234] The display unit 6511 supports HD (1280 x 720 pixels), FHD (1920 x 108 0), WQHD (pixel count 2560 x 1440), WQXGA (pixel count 2560 x 1600 ), 4K (3840 x 2160 pixels), 8K (7680 x 4320 pixels) It is preferable that the image has a high resolution, especially 4K, 8K or higher. In addition, it is preferable that the pixel density (resolution) of the pixels provided in the display portion 6511 is 300 ppi or more, preferably 500 ppi or more, more preferably 800 ppi or more, It is more preferable that the resolution is 1000 ppi or more, and even more preferable that the resolution is 1200 ppi or more. The display unit 6511 having such high resolution and high definition makes it possible to For personal use such as at home, it is important to enhance the sense of realism and depth. It becomes possible.

[0235] The IC 6520 includes a circuit unit 6501, a signal line driver circuit 6502, and a sensor driver circuit 65 The circuit unit 6501 includes a timing controller 6503 and a detection circuit 6504. The image processing circuit 6506 is also included.

[0236] The signal line driver circuit 6502 transmits an analog video signal to the signal line of the display portion 6511. For example, the signal line driver circuit 6502 has a function of outputting a signal (also called a video signal). In addition, it is possible to have a configuration in which a shift register circuit and a buffer circuit are combined. The touch panel 6510 may also have a demultiplexer circuit connected to the signal lines. stomach.

[0237] The sensor driving circuit 6503 outputs a signal that drives the detection element of the input unit 6512. The sensor driver circuit 6503 includes, for example, a shift register circuit and a buffer circuit. A combination of circuits may be used.

[0238] The detection circuit 6504 receives an output signal from the detection element of the input section 6512 and outputs it to the circuit unit 6 501. For example, the detection circuit 6504 may include an amplifier circuit and an analog Equipped with a digital conversion circuit (ADC: Analog-Digital Converter) In this case, the detection circuit 6504 receives the output from the input section 6512. The analog signal is converted into a digital signal and output to the circuit unit 6501 .

[0239] The image processing circuit 6506 of the circuit unit 6501 is The function of generating and outputting a signal to drive the input section 6511 is and a function to analyze the signal output from the input unit 6512 and output it. and a function to output the same to the

[0240] As a more specific example, the image processing circuit 6506 performs the following in accordance with an instruction from the CPU 6540: The image processing circuit 6506 has a function of generating a video signal. The video signal is subjected to signal processing in accordance with the received signal, converted into an analog video signal, and transmitted to the signal line driving circuit 65. The image processing circuit 6506 also has the function of supplying the image data to the CPU 6540. In accordance with the above, the sensor driver circuit 6503 generates a driving signal. The image processing circuit 6506 analyzes the signal input from the detection circuit 6504 and outputs it as position information. It has the function of outputting to the CPU 6540.

[0241] The timing controller 6505 also receives the video signal processed by the image processing circuit 6506. Based on the synchronization signals included in the It has a function of outputting to the scanning line driver circuit 6513 and the sensor driver circuit 6503. The timing controller 6505 determines the timing at which the detection circuit 6504 outputs a signal. The timing controller 6 may have a function to generate and output a signal. 505 is a signal output to the scanning line driver circuit 6513 and a signal output to the sensor driver circuit 6503. It is preferable that the display unit 6511 outputs signals synchronized with the signals received from the display unit 6511. The period for rewriting pixel data and the period for sensing by the input unit 6512 are respectively For example, one frame period can be divided into a period for rewriting pixel data and a period for The touch panel 6510 can be driven in separate periods, i.e., a period for sensing. For example, by providing two or more sensing periods in one frame period, the detection sensitivity and detection accuracy can be improved. The degree can be increased.

[0242] The image processing circuit 6506 can be configured to include, for example, a processor. For example, DSP (Digital Signal Processor), GPU (Graphics Processing Unit) Microprocessors such as the Microprocessor Processing Unit (MPU) can be used. These microprocessors can also be implemented as FPGAs (Field Programmable Gate Arrays). e Gate Array) and FPAA (Field Programmable An PLDs (Programmable Logic Devices) such as analog arrays The processor may be configured to execute various programs. It processes various data and controls programs by interpreting and executing instructions. The program that can be executed by the processor may be stored in a memory area of ​​the processor. Alternatively, the information may be stored in a separately provided storage device.

[0243] Note that the display portion 6511 or the scanning line driver circuit 6513 of the touch panel 6510 The IC 6520 includes a circuit unit 6501, a signal line driver circuit 6502, and a sensor driver circuit. 6503, or the detection circuit 6504, or the CPU 6540 provided externally, By using an oxide semiconductor in the channel formation region, a transistor with extremely low off-state current was developed. Since the off-state current of the transistor is extremely low, The capacitor functions as a memory element, and the switch is used to hold the charge (data) that has flowed into the capacitor. By using it as a switch, data retention period can be secured for a long period. For example, This characteristic is used for at least one of the register and cache memory of the image processing circuit 6506. By doing so, the image processing circuit 6506 operates only when necessary, and in other cases, the previous processing By saving the information in the storage element, normally-off computing becomes possible. This enables the touch panel module 6500 and the electronic device in which it is mounted to consume less power. This will enable us to strengthen our capabilities.

[0244] In this example, the circuit unit 6501 is a timing controller 6505 and an image processing circuit Although the image processing circuit 6506 is configured to include the image processing circuit 6506 itself, A circuit having some of the functions of the image processing circuit 6506 may be provided externally. For example, the circuit unit 6501 may perform the signal processing. A signal line driving circuit 6502, a sensor driving circuit 6503, a detection circuit 6504, and a timing controller It may also be configured with a controller 6505.

[0245] Although an example in which the IC 6520 includes the circuit unit 6501 has been shown here, the circuit unit 6501 can be configured not to be included in IC6520. In this case, IC6520 is A configuration including a signal line driver circuit 6502, a sensor driver circuit 6503, and a detection circuit 6504. For example, when multiple ICs are mounted on the touch panel module 6500, In this case, the circuit unit 6501 is provided outside the touch panel module 6500. It is also possible to arrange a plurality of ICs 6520 that do not have a slot 6501, or to arrange ICs 6520 and It is also possible to combine and arrange an IC having only the signal line driver circuit 6502 .

[0246] In this way, the touch panel 6510 has a function of driving the display unit 6511 and a function of driving the input unit 6512. The touch panel module is made up of a single IC incorporating the functions to drive the touch panel. This reduces the number of ICs mounted on the 6500, thereby reducing costs. do.

[0247] Figures 16(A), (B), and (C) show touch panel modules 65 equipped with IC6520. This is a schematic diagram of 00.

[0248] In FIG. 16A, the touch panel module 6500 includes a substrate 6531 and an opposing substrate 653 2. Multiple FPC6533, IC6520, IC6530, etc. Also, PCB6531 A display portion 6511, an input portion 6512, and a scanning line driver circuit 65 are disposed between the substrate 6532 and the opposing substrate 6532. 13. The IC6520 and IC6530 are mounted using a COG method or other mounting method. It is mounted on board 6531.

[0249] The IC6530 is the IC6520 described above, except that only the signal line driver circuit 6502 or The IC 6520 includes a signal line driver circuit 6502 and a circuit unit 6501. The IC6530 receives external signals via FPC6533. 33, and outputs a signal from at least one of IC6520 and IC6530 to the outside. It is possible.

[0250] In FIG. 16A, two scanning line driver circuits 6513 are provided so as to sandwich a display portion 6511. Also shown is a configuration having IC6530 in addition to IC6520. Such a configuration can be suitably used when the display unit 6511 has extremely high resolution. can.

[0251] Figure 16(B) shows an example where one IC6520 and one FPC6533 are mounted. In this way, by consolidating the functions into one IC6520, the number of parts can be reduced. 16B, the scanning line driver circuit 6513 is connected to the display portion 6511. This shows an example where the board is placed along the side closest to the FPC6533.

[0252] FIG. 16C shows a PCB (Printed Circuit) on which the image processing circuit 6506 and other components are mounted. 6 shows an example of a configuration having an IC on a substrate 6531. 6520 and IC6530 are electrically connected to PCB6534 by FPC6533. Here, the IC 6520 does not have the image processing circuit 6506. can be applied.

[0253] In each diagram of FIG. 16, IC6520 and IC6530 are mounted on a substrate 6531. It may be mounted on an FPC6533 instead of IC6520. For example, IC6530 can be mounted on the FPC6533 using mounting methods such as COF or TAB. Cut.

[0254] As shown in FIGS. 16A and 16B, the FPC 6533 and IC The configuration in which IC6520 (and IC6530) etc. are arranged allows for a narrow frame, so for example, It can be suitably used in electronic devices such as smartphones, mobile phones, and tablet terminals. In addition, the configuration using PCB6534 as shown in FIG. 16(C) is suitable for, for example, a television. Suitable for use in laptops, monitors, tablets, and notebook computers. It can be used appropriately.

[0255] This embodiment mode can be combined with other embodiment modes as appropriate.

[0256] (Embodiment 2) In this embodiment, a manufacturing method of an input / output device of one embodiment of the present invention will be described with reference to FIGS. In this embodiment, a method for manufacturing a transistor will be mainly described. For the material, reference can be made to the description in embodiment 1.

[0257] First, the gate electrode 221 is formed on the substrate 211. Then, the substrate 211 and the gate electrode An insulating film 213 including insulating films 106 and 107 is formed on the film 221 (FIG. 17(A)).

[0258] In this embodiment, a glass substrate is used as the substrate 211, and a tongue is used as the gate electrode 221. A stainless steel film is used as the insulating film 106, and a silicon nitride film capable of releasing hydrogen is used as the insulating film 107. For the insulating film 107, a silicon oxide film capable of releasing oxygen is used.

[0259] The insulating film 106 functions as a blocking film that suppresses oxygen permeation. For example, At least one of the insulating film 107, the insulating film 215, the insulating film 217, and the oxide semiconductor film 223 When excess oxygen is supplied to either layer, the insulating film 106 suppresses the permeation of oxygen. It is possible.

[0260] Note that the insulating film in contact with the oxide semiconductor film 223 which functions as a channel region of the transistor The insulating film 107 is preferably an oxide insulating film containing oxygen in excess of the stoichiometric composition. In other words, the insulating film 107 has a region where the amount of oxygen is excessive (an oxygen-excess region). The insulating film 107 is an insulating film capable of releasing oxygen. For example, the insulating film 107 can be formed in an oxygen atmosphere. Oxygen may be introduced into the insulating film 107 to form an oxygen-excess region. These include ion implantation, ion doping, plasma immersion ion implantation, and plasma Processing such as masking can be used.

[0261] When hafnium oxide is used for one or both of the insulating films 106 and 107, Hafnium oxide has the following advantages: It has a low dielectric constant compared to silicon oxide and silicon oxynitride. Therefore, compared with the case where silicon oxide is used, the insulating film 106 and the insulating film Since the thickness of one or both of the layers 107 can be increased, the leakage current due to the tunnel current can be reduced. That is, a transistor with a small off-state current can be realized. Furthermore, hafnium oxide with a crystalline structure has a higher melting point than hafnium oxide with an amorphous structure. Therefore, in order to make a transistor with a small off-state current, It is preferable to use hafnium oxide having a crystalline structure. Examples of the crystal system include a clinic system and a cubic system. However, one embodiment of the present invention is not limited to these. .

[0262] In this embodiment, a silicon nitride film is formed as the insulating film 106, and a silicon nitride film is formed as the insulating film 107. The silicon nitride film has a lower dielectric constant than the silicon oxide film. The film thickness required to obtain the same capacitance as a silicon oxide film is large. The insulating film 213 that functions as the gate insulating film of the insulating film 213 includes a silicon nitride film. This allows the thickness of the transistor to be increased physically. Furthermore, it is possible to improve the dielectric strength voltage and suppress electrostatic breakdown of the transistor.

[0263] The gate electrode 221 is formed by depositing a conductive film on the substrate 211 and then removing the conductive film so that a desired region of the conductive film remains. The pattern can be formed by patterning the film and then etching away the unnecessary areas.

[0264] Next, an oxide semiconductor film 223 is formed over the insulating film 213 at a position overlapping with the gate electrode 221. (Figure 17(B)).

[0265] In this embodiment, the oxide semiconductor film 223 is an In—Ga—Zn oxide film (In:G A metal oxide target with an atomic ratio of a:Zn=1:1:1.2 is used.

[0266] The oxide semiconductor film 223 is formed by depositing an oxide semiconductor film over the insulating film 213 and then The conductive film is patterned so that the desired area remains, and then the unnecessary area is etched away. It can be formed by

[0267] After the oxide semiconductor film 223 is formed, heat treatment is preferably performed. 50°C or less, preferably 300°C or more and 500°C or less, more preferably 350°C or more and 450°C or less At temperatures below ℃, in an inert gas atmosphere, an atmosphere containing 10 ppm or more of oxidizing gas, or reduced pressure The heat treatment can be carried out in an inert gas atmosphere. The oxide semiconductor film 223 contains an oxidizing gas at a concentration of 10 ppm or more to compensate for oxygen released from the oxide semiconductor film 223. The heat treatment here may be performed in a SiO 2 atmosphere. Impurities such as hydrogen and water can be removed from at least one of the conductive films 223. The heat treatment may be performed before the oxide semiconductor film 223 is processed into an island shape.

[0268] Note that the transistor having the oxide semiconductor film 223 as a channel region can have stable electrical characteristics. In order to achieve this, impurities in the oxide semiconductor film 223 are reduced to make the oxide semiconductor film 223 pure. It is advantageous to make the information authentic or substantially authentic.

[0269] Next, a conductive film is formed over the insulating film 213 and the oxide semiconductor film 223. The insulating film 21 is patterned so that the unnecessary area remains, and then the unnecessary area is etched away. 3 and a source electrode 225a and a drain electrode 225b are formed on the oxide semiconductor film 223. (Figure 17(C)).

[0270] In this embodiment, the source electrode 225a and the drain electrode 225b are made of tungsten. It uses a three-layer laminated structure of a silicon film, an aluminum film, and a titanium film.

[0271] After the source electrode 225a and the drain electrode 225b are formed, the oxide semiconductor film 223 The surface of the substrate may be cleaned by, for example, cleaning using a chemical solution such as phosphoric acid. By cleaning with a chemical solution such as phosphoric acid, the surface of the oxide semiconductor film 223 Impurities (for example, elements contained in the source electrode 225a and the drain electrode 225b) attached to the However, this cleaning is not always necessary, and in some cases it may be necessary to In this case, cleaning may not be necessary.

[0272] In addition, the process of forming the source electrode 225a and the drain electrode 225b and the cleaning process In either one or both of the oxide semiconductor film 223, the source electrode 225a and the drain electrode 225b are The area exposed from the back electrode 225b may be thin.

[0273] Next, the insulating film 213, the oxide semiconductor film 223, the source electrode 225a, and the drain electrode 225b are An insulating film 215 including insulating films 114 and 116 is formed on the insulating film 25b. The desired area is patterned to remain, and then the unnecessary area is etched away to form a hole. A mouth 141 is formed (FIG. 17(D)).

[0274] After the insulating film 114 is formed, the insulating film 116 is successively formed without exposing it to the air. After the insulating film 114 is formed, it is preferable to control the flow rate, pressure, and high frequency of the source gas without exposing the insulating film 114 to the atmosphere. By adjusting one or more of the wave power and the substrate temperature, the insulating film 116 is continuously formed. The concentration of impurities derived from atmospheric components can be reduced at the interface between the film 114 and the insulating film 116. At the same time, oxygen contained in the insulating films 114 and 116 is transferred to the oxide semiconductor film 223. As a result, the amount of oxygen vacancies in the oxide semiconductor film 223 can be reduced.

[0275] In the step of forming the insulating film 116, the insulating film 114 serves as a protective film for the oxide semiconductor film 223. Therefore, it is possible to reduce damage to the oxide semiconductor film 223 and increase the power density. The insulating film 116 can be formed using low high frequency power.

[0276] In this embodiment, the insulating films 114 and 116 are formed of oxynitride film capable of releasing oxygen. A silicon film is used.

[0277] The insulating film 114 in contact with the oxide semiconductor film 223 which functions as a channel region of the transistor The insulating film is preferably an oxide insulating film, and an insulating film capable of releasing oxygen is used. In other words, an insulating film that can release oxygen is one that contains oxygen in excess of the stoichiometric composition. The insulating film 114 has an oxygen-excess region. To provide the insulating film 114, for example, the insulating film 114 can be formed in an oxygen atmosphere. Alternatively, oxygen may be introduced into the insulating film 114 after it has been formed to form an oxygen-excess region. The methods include ion implantation, ion doping, and plasma immersion ion implantation. , plasma treatment, etc. can be used.

[0278] By using an insulating film capable of releasing oxygen as the insulating film 114, Oxygen is transferred to the oxide semiconductor film 223 which functions as a channel region of the oxide semiconductor film 222. For example, the amount of oxygen vacancies in 223 can be reduced by thermal desorption spectroscopy (T DS (Thermal Desorption Spectroscopy) analysis .) The surface temperature of the film is 100°C or higher and 700°C or lower, or 100°C or higher. The amount of oxygen molecules released in the range below 500°C is 1.0 × 10 18 molecules / cm 3 That's all By using an insulating film, the amount of oxygen vacancies in the oxide semiconductor film 223 can be reduced. can be done.

[0279] Furthermore, it is preferable that the insulating film 114 has a small number of defects. , the spin density of the signal appearing at g=2.001 due to the silicon dangling bond is 3×10 17 spins / cm 3 This is because the insulating film 114 contains If the density of defects contained in the insulating film 114 is high, oxygen will be bonded to the defects, and the oxygen in the insulating film 114 will be In addition, the amount of light transmitted between the insulating film 114 and the oxide semiconductor film 223 decreases. It is preferable that the number of defects at the interface is small. Typically, it is preferable that the oxide semiconductor is The spin density of the signal that appears when the g value is between 1.89 and 1.96 due to defects in the conductive film 223 Degrees are 1 x 10 17 spins / cm 3 or less, and more preferably below the lower limit of detection. .

[0280] In the insulating film 114, all of the oxygen that has entered the insulating film 114 from the outside is Alternatively, some of the oxygen that has entered the insulating film 114 from the outside may move to the outside of the insulating film 114. In some cases, oxygen may enter the insulating film 114 from the outside, and the oxygen may also enter the insulating film 114. The oxygen contained in the insulating film 114 moves to the outside of the insulating film 114, and The insulating film 114 may be made of an oxide film that allows oxygen to pass through. When the insulating film 114 is formed, oxygen desorbed from the insulating film 116 is The oxide semiconductor film 223 can be transferred to the oxide semiconductor film 223 through the insulating film 114.

[0281] The insulating film 114 is formed using an oxide insulating film with a low density of states due to nitrogen oxides. Note that the density of states due to the nitrogen oxide can be determined by the valence charge of the oxide semiconductor film. The energy at the top of the nucleus (E V_OS ) and the energy of the bottom of the conduction band of the oxide semiconductor film ( E C_OS ) may be formed between the insulating film and the insulating layer. Silicon oxynitride film with low nitrogen oxide emission or aluminum oxynitride film with low nitrogen oxide emission A rubber film or the like can be used.

[0282] In addition, the silicon oxynitride film, which emits a small amount of nitrogen oxide, does not emit any nitrogen oxide in the TDS analysis. This is a membrane that releases more ammonia than chlorides, and typically releases ammonia molecules. The amount is 1 x 10 18 molecules / cm 3 5x10 or more 19 molecules / cm 3 The following is the case. The amount of Nia released is determined when the surface temperature of the film is 50°C or higher and 650°C or lower, preferably 50°C or higher and 550°C or lower. The amount released by heating at or below ℃.

[0283] Nitrogen oxides (NO x , x is greater than 0 and less than or equal to 2, preferably greater than or equal to 1 and less than or equal to 2), typically NO or NO forms a level in the insulating film 114 or the like. 23. Therefore, the nitrogen oxide is in the insulating film 114 and the oxide film. When the electrons diffuse to the interface of the oxide semiconductor film 223, the level transfers electrons on the insulating film 114 side. As a result, the trapped electrons may be trapped between the insulating film 114 and the oxide semiconductor. Since it remains near the interface of the film 223, it shifts the threshold voltage of the transistor in the positive direction. It ends up like this.

[0284] Nitrogen oxide reacts with ammonia and oxygen during heat treatment. The nitrogen oxide contained therein reacts with the ammonia contained in the insulating film 116 during the heat treatment. Therefore, nitrogen oxides contained in the insulating film 114 are reduced. Electrons are less likely to be trapped at the interface with the oxide semiconductor film 223.

[0285] By using the oxide insulating film as the insulating film 114, the threshold voltage of the transistor can be reduced. It is possible to reduce the shift and the fluctuation of the electrical characteristics of the transistor. Cut.

[0286] Note that the heat treatment in the manufacturing process of the transistor is typically performed at a temperature lower than 400° C. or lower than 375° C. ( The insulating film 114 is heated to 100 K by heat treatment at a temperature of preferably 340° C. or higher and 360° C. or lower. In the spectrum obtained by measuring the following ESR, the g value is 2.037 or more and 2.039 or less. The first signal below, the second signal with a g-value between 2.001 and 2.003, and the g-value The third signal is observed, with a value between 1.964 and 1.966. and the split width of the second signal, and the split width of the second signal and the third signal. The bit width is about 5 mT in the X-band ESR measurement. The first signal is less than or equal to 2.039, and the second signal is between 2.001 and 2.003. The sum of the spin densities of the 3rd signal with g values ​​between 1.964 and 1.966 is 1×10 18 spins / cm 3 less than 1 × 10 17 spins / cm 3 More than 1×10 18 spins / cm 3 is less than.

[0287] In addition, in the ESR spectrum below 100K, the g value is between 2.037 and 2.039. The first signal, the second signal with a g value between 2.001 and 2.003, and the g value between 1. The third signal, between 964 and 1.966, is nitrogen oxide (NO x , x is greater than 0 2 or less, preferably 1 to 2). Examples include nitrogen monoxide and nitrogen dioxide. The first signal, the second signal with a g value of 2.001 or more and 2.003 or less, and the g value of 1 The lower the sum of the spin densities of the third signals (between 0.964 and 1.966), the higher the oxidation It can be said that the content of nitrogen oxides contained in the insulating film is small.

[0288] The oxide insulating film has a nitrogen concentration of 6×10 as measured by SIMS. 20 atoms / cm 3 The following is the result.

[0289] PECV using silane and nitrous oxide at a substrate temperature of 220°C or higher and 350°C or lower By forming the oxide insulating film using Method D, a dense and hard film can be formed. It can be achieved.

[0290] The insulating film 116 formed in contact with the insulating film 114 has a stoichiometric composition of oxygen. The oxide insulating film contains more oxygen than the stoichiometric composition. When an oxide insulating film contains a large amount of oxygen, some of the oxygen is released by heating. The oxide insulating film containing more oxygen than the oxygen that satisfies the condition is converted to oxygen atoms by TDS analysis. The amount of oxygen released is 1.0 × 10 19 atoms / cm 3 or more, preferably 3.0 x 1 0 20 atoms / cm 3 The oxide insulating film is as described above. The surface temperature of the film is in the range of 100°C to 700°C or 100°C to 500°C. The surrounding area is preferred.

[0291] Furthermore, it is preferable that the insulating film 116 has a small number of defects. , the spin density of the signal appearing at g=2.001 due to the silicon dangling bond is 1.5×10 18 spins / cm 3 Less than or even 1×10 18 spins / cm 3 below Note that the insulating film 116 is preferably an oxide semiconductor film, as compared with the insulating film 114. Since it is far from the insulating film 223, it may have a higher defect density than the insulating film 114.

[0292] The thickness of the insulating film 114 is 5 nm or more and 150 nm or less, preferably 5 nm or more and 50 nm or less. The thickness of the insulating film 116 can be set to 30 nm or more, preferably 10 nm or more and 30 nm or less. The thickness can be 0 nm or more and 500 nm or less, preferably 150 nm or more and 400 nm or less. do.

[0293] In addition, the insulating films 114 and 116 can be made of the same material. In this case, the interface between the insulating film 114 and the insulating film 116 may not be clearly visible. In this embodiment, the interface between the insulating film 114 and the insulating film 116 is shown by a dashed line. In this embodiment, the two-layer structure of the insulating film 114 and the insulating film 116 has been described. However, the present invention is not limited to this, and examples thereof include a single layer structure of the insulating film 114, a single layer structure of the insulating film 116, and Alternatively, the laminated structure may be three or more layers.

[0294] After the insulating films 114 and 116 are formed, heat treatment (hereinafter referred to as first heat treatment) is performed. The first heat treatment is preferably performed to remove nitrogen oxides contained in the insulating films 114 and 116. Alternatively, the first heat treatment can reduce the amount of the oxides contained in the insulating films 114 and 116. Part of the oxygen contained in the oxide semiconductor film 223 is moved to the oxide semiconductor film 223. The amount of oxygen deficiency can be reduced.

[0295] The temperature of the first heat treatment is typically less than 400°C, preferably less than 375°C, and The temperature is preferably 150° C. or higher and 350° C. or lower. The first heat treatment is carried out in an atmosphere of nitrogen, oxygen, or ultra-dry. Air (water content is 20 ppm or less, preferably 1 ppm or less, more preferably 10 ppm or less) This can be done under an atmosphere of air (<100 psi) or a rare gas (argon, helium, etc.). It is preferable that the nitrogen, oxygen, ultra-dry air, or rare gas does not contain hydrogen, water, or the like. The heat treatment is carried out using an electric furnace, RTA (Rapid Thermal Anneal), etc. You can be there.

[0296] The opening 141 is formed so as to expose the drain electrode 225b. For example, a dry etching method can be used as the forming method. The method for forming the first insulating film 1 is not limited to this, and may be a wet etching method or a dry etching method. The opening 141 may be formed by a combination of the wetting method and the wet etching method. The thickness of the drain electrode 225b may be reduced by the etching process for forming the drain electrode 225b. be.

[0297] Next, an oxide conductive film 227 that will be formed later is formed on the insulating film 116 so as to cover the opening 141. A compound semiconductor film is formed (FIGS. 18(A) and 18(B)).

[0298] Note that FIG. 18A shows the inside of a film formation apparatus when an oxide semiconductor film is formed over the insulating film 116. In FIG. 18(A), a sputtering device is used as the film forming device. A target 193 is installed inside the sputtering device, and a The formed plasma 194 is shown schematically.

[0299] First, when forming an oxide semiconductor film, plasma is discharged in an atmosphere containing a third oxygen gas. At this time, oxygen is added to the insulating film 116, which is a surface where the oxide semiconductor film is to be formed. When forming the oxide semiconductor film, an inert gas (for example, For example, argon, helium, argon, xenon, etc. may be mixed. The flow rate of the third oxygen gas is set higher than that of the argon gas. By increasing the flow rate of the third oxygen gas, the insulating film 11 can be favorably Oxygen can be added to the oxide semiconductor film 6. For example, the oxide semiconductor film can be formed under the following conditions: The ratio of the third oxygen gas to the entire deposition gas is 50% or more and 100% or less, preferably It can be between 80% and 100%.

[0300] In FIG. 18A, oxygen or excess oxygen added to the insulating film 116 is schematically shown as a broken line. It is represented by a line arrow.

[0301] The substrate temperature during the formation of the oxide semiconductor film is preferably room temperature or higher and lower than 340° C. Preferably, the temperature is from room temperature to 300°C, more preferably from 100°C to 250°C, and even more preferably The temperature is 100° C. or higher and 200° C. or lower. On the other hand, the substrate 211 is a large glass substrate. When using a semiconductor device (for example, 6th to 10th generations), the substrate temperature during the formation of the oxide semiconductor film If the temperature is set to 150° C. or higher and lower than 340° C., the substrate 211 may deform (distort or warp). Therefore, when a large glass substrate is used, it is necessary to form an oxide semiconductor film on the large glass substrate. By keeping the substrate temperature at the time of application at 100°C or higher but lower than 150°C, deformation of the glass substrate can be suppressed. This can be done.

[0302] In this embodiment, an In-Ga-Zn metal oxide target (In:Ga:Zn=1:3) :6 [atomic ratio]) by a sputtering method to form an oxide semiconductor film.

[0303] Next, the oxide semiconductor film is processed into a desired shape to form an island-shaped oxide semiconductor film 227a (Figure 18(C)).

[0304] The oxide semiconductor film 227a is formed by depositing an oxide semiconductor film over the insulating film 116 and then The film is patterned to leave the desired areas, and then the unwanted areas are etched away. It can be formed.

[0305] Next, the insulating film 217 is formed over the insulating film 116 and the oxide semiconductor film 227a (FIG. 19( A)).

[0306] The insulating film 217 can block oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. By providing the insulating film 217, oxygen from the oxide semiconductor film 223 can be effectively removed. The diffusion of oxygen contained in the insulating film 215 to the outside and the diffusion of oxygen from the outside to the oxide semiconductor film It can prevent hydrogen, water, alkali metals, alkaline earth metals, etc. from entering 223 .

[0307] The insulating film 217 preferably contains either hydrogen or nitrogen, or both. For example, a silicon nitride film is preferably used as the insulating film 217. For example, the film can be formed by sputtering or PECVD. For example, when the insulating film 217 is formed by the PECVD method, the substrate temperature is preferably less than 400° C. The temperature is preferably less than 375°C, more preferably 180°C or higher and 350°C or lower. By setting the substrate temperature in the above range when forming the film, it is possible to form a dense film, which is preferable. In addition, by setting the substrate temperature in the above range when forming the insulating film 217, the insulating film 1 Oxygen or excess oxygen in the oxide semiconductor film 14 or 116 can be transferred to the oxide semiconductor film 223. become.

[0308] In addition, it has a blocking effect against oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. Instead of a nitride insulating film, an oxide insulating film having a blocking effect against oxygen, hydrogen, water, etc. is used. As the oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like, an oxide insulating film such as an oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like may be provided. Aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, gallium oxide Examples include yttrium oxide, yttrium oxynitride, hafnium oxide, and hafnium oxynitride.

[0309] After the insulating film 217 is formed, a heat treatment similar to the first heat treatment described above (hereinafter referred to as the first heat treatment) is performed. In this way, the oxide semiconductor that becomes the oxide conductive film 227 may be subjected to the heat treatment (heat treatment in step 2). After adding oxygen to the insulating film 116 during the formation of the conductor film, the insulating film 116 is heated to a temperature lower than 400° C., preferably 37° C. By performing heat treatment at a temperature of less than 5°C, more preferably at a temperature of 180°C or higher and 350°C or lower, Oxygen or excess oxygen in the insulating film 116 is transferred to the oxide semiconductor film 223, and the oxide semiconductor This can compensate for the oxygen deficiency in the membrane 223.

[0310] Here, oxygen moving into the oxide semiconductor film 223 will be described with reference to FIGS. FIG. 20 shows the temperature of the substrate during the formation of the insulating film 217 (typically less than 375° C.) or the temperature of the insulating film 21 The oxide semiconductor film 22 is formed by a second heat treatment (typically at a temperature lower than 375° C.) after the formation of the oxide semiconductor film 22. 20 is a model diagram showing oxygen moving into the oxide semiconductor film 223. The oxygen (oxygen radical, oxygen atom, or oxygen molecule) migrating to the oxygen atom is represented by a dashed arrow. FIG. 20 is a cross-sectional view of the transistor and its vicinity after the insulating film 217 is formed.

[0311] The oxide semiconductor film 223 shown in FIG. 20 is a film in contact with the oxide semiconductor film 223 (here, an insulating film Oxygen vacancies are compensated for by the migration of oxygen from the insulating film 107 and the insulating film 114. In the input / output device of one embodiment of the present invention, When oxygen gas is used to add oxygen to the insulating film 107 during sputtering, The film 107 has an excess oxygen region. During sputtering, oxygen gas is used to add oxygen to the insulating film 116. 116 has an excess oxygen region. Therefore, the oxide film sandwiched between the insulating films having the excess oxygen region In the compound semiconductor film 223, oxygen vacancies are suitably filled.

[0312] Further, the insulating film 106 is provided below the insulating film 107, and the insulating films 114 and 116 An insulating film 217 is provided above the insulating films 106 and 217. By forming the insulating films 107, 114, and 116 using a material such as silicon nitride, Since oxygen contained in the oxide semiconductor film 223 can be trapped in the oxide semiconductor film 223, the oxide semiconductor film 223 can be suitably Oxygen can be transferred to the semiconductor film 223 .

[0313] In addition, the insulating film 217 preferably has a function of reducing the resistivity of the oxide conductive film 227. I wish.

[0314] By forming the insulating film 217 containing either hydrogen or nitrogen or both, the insulating film 2 The oxide semiconductor film 227a in contact with the oxide semiconductor film 17 is doped with either or both of hydrogen and nitrogen. As a result, the carrier density of the oxide semiconductor film 227a is increased, and the oxide conductive film It can function as.

[0315] As the resistivity of the oxide semiconductor film 227a decreases, the oxide conductive film 227b is It is shown as membrane 227 .

[0316] The resistivity of the oxide conductive film 227 is at least lower than that of the oxide semiconductor film 223, and is preferably is 1 x 10 -3 Ωcm or more 1×10 4 Less than Ωcm, more preferably 1×10 -3 Ω cm or more 1×10 -1 It is preferable that the resistivity is less than Ωcm.

[0317] Next, an insulating film 219 is formed on the insulating film 217, and desired regions of the insulating films 217 and 219 are left. Then, unnecessary areas are etched to form openings 142. (Figure 19(B)).

[0318] In this embodiment, the insulating film 219 is made of an acrylic resin.

[0319] The opening 142 is formed so as to expose the drain electrode 225b. For example, a dry etching method can be used as the forming method. The method for forming 2 is not limited to this, but may be wet etching or dry etching. The opening 142 may be formed by a combination of the wetting method and the wet etching method. The thickness of the drain electrode 225b may be reduced by the etching process for forming the drain electrode 225b. be.

[0320] In addition, the step of forming the opening 142 is performed without performing the step of forming the opening 141. The openings may be formed continuously in the insulating films 114, 116, 217, and 219. This makes it possible to reduce the manufacturing steps of the input / output device of one embodiment of the present invention. This allows the manufacturing cost to be reduced.

[0321] Next, a conductive film is formed on the insulating film 219 so as to cover the opening 142, and a desired region of the conductive film is The conductive film 25 is patterned so that unnecessary areas remain, and then unnecessary areas are etched away. Further, an insulating film 253 is formed on the conductive film 251. Next, A conductive film is formed on the surface, and patterned so that a desired region of the conductive film remains. The conductive film 255 is formed by etching the region. A conductive film is formed on the film 255 and patterned so that a desired region of the conductive film remains. After that, unnecessary regions are etched to form a conductive film 252 (FIG. 19(C)).

[0322] In this embodiment, ITO films are used as the conductive films 251 and 252, and the insulating film 253 A silicon nitride film was used as the conductive film 255, and an alloy of silver, palladium and copper (Ag-P A d-Cu (also referred to as APC) membrane is used.

[0323] The order of forming the conductive film 252 and the conductive film 255 does not matter. It is preferable that the conductive film 255 is formed before the conductive film 252 is formed by etching. It can reduce the damage you receive.

[0324] Note that the conductive film 251 is formed using an oxide semiconductor film by a method similar to that for the oxide conductive film 227. In this case, the insulating film 253 formed on the conductive film 251 may be the insulating film 217. In addition, a material that can be used for forming an oxide semiconductor film can be applied. The conductive film 252 may be formed by performing treatment to reduce the resistivity of the oxide semiconductor film. .

[0325] Through the above steps, the transistor 203b and the pair of electrodes of the liquid crystal element shown in FIG. 4 are formed. It can be made.

[0326] Although the insulating film 219 is provided in FIG. 19C, the insulating film 219 is not provided. It may also be configured as shown in FIG. 21.

[0327] This embodiment mode can be combined with other embodiment modes as appropriate.

[0328] (Embodiment 3) In this embodiment, a transistor that can be used for an input / output device of one embodiment of the present invention will be described. 22 to 25. The materials of each layer are the same as those described in the first embodiment. Please refer to the above.

[0329] <Transistor configuration example 1> 22A is a top view of transistor 270, and FIG. 22B is a top view of the transistor 270 shown in FIG. 22(C) is a cross-sectional view taken along dashed line A1-A2, and FIG. 22(D) is a cross-sectional view taken along dashed line B1-B2. The dashed-dotted line A1-A2 direction is the channel length direction, and the dashed-dotted line B1-B2 direction is the channel length direction. This direction may be referred to as the channel width direction.

[0330] The transistor 270 includes a conductive film 504 over a substrate 502, which serves as a first gate electrode, and a an insulating film 506 on the substrate 502 and the conductive film 504; an insulating film 507 on the insulating film 506; The oxide semiconductor film 508 over the insulating film 507 and the insulating film 508 electrically connected to the oxide semiconductor film 508 The conductive film 512a serving as a source electrode and the oxide semiconductor film 508 The conductive film 512b functions as a drain electrode, and the oxide semiconductor film 508 and the conductive film 512 The insulating films 514 and 516 on the conductive film 512a and the conductive film 512b, and the oxide conductive film 51 on the insulating film 516 An insulating film 518 is provided over the oxide conductive film 511b.

[0331] In the transistor 270, the insulating film 514 and the insulating film 516 The oxide semiconductor film 511a functions as a second gate insulating film. 14 and the insulating film 516 through an opening 552c formed in the insulating film 516. The oxide semiconductor film 511a functions as, for example, a pixel electrode of a display element. In addition, in the transistor 270, the oxide conductive film 511b is a second gate electrode (back gate electrode). It functions as a gate electrode.

[0332] As shown in FIG. 22C, the oxide conductive film 511b is formed by insulating films 506 and 507 and insulating The first gate electrode is formed in openings 552a and 552b in the film 514 and the insulating film 516. Therefore, the conductive film 504 and the oxide conductive film The same potential is applied to 511b.

[0333] In this embodiment, the openings 552a and 552b are provided, and the oxide conductive film 511 However, the present invention is not limited to this. Only one of the openings 552a and 552b is formed, and the oxide conductive film 5 11b and the conductive film 504 are connected, or the openings 552a and 552b are not provided. Alternatively, the oxide conductive film 511b and the conductive film 504 may not be connected to each other. In the case where the conductive film 511b and the conductive film 504 are not connected, the oxide conductive film 511b and the conductive film Each of the electrodes 504 can be given a different potential.

[0334] As shown in FIG. 22B, the oxide semiconductor film 508 functions as a first gate electrode. The conductive film 504 functions as a second gate electrode, and the oxide conductive film 511b functions as a second gate electrode. It is positioned opposite to the gate electrode and is sandwiched between two conductive films that function as gate electrodes. The length in the channel length direction of the oxide conductive film 511b functioning as the gate electrode of The length in the channel width direction is the length of the oxide semiconductor film 508 in the channel length direction and the The length of the oxide semiconductor film 508 is longer than the length of the insulating film 514 and the insulating film 51 The gate electrode 511b is covered with the oxide conductive film 511b via the gate electrode 511c. The oxide conductive film 511b and the conductive film 504 functioning as the first gate electrode are formed by insulating film 5 506, 507, the insulating film 514 and the openings 552a, 552b provided in the insulating film 516. Therefore, the side surface of the oxide semiconductor film 508 in the channel width direction is covered with the insulating film 514. and faces the oxide conductive film 511b functioning as a second gate electrode with the insulating film 516 interposed therebetween. is doing.

[0335] In other words, in the channel width direction of the transistor 270, The conductive film 504 functioning as the second gate electrode and the oxide conductive film 511b functioning as the gate electrode are The insulating films 506 and 507 function as first gate insulating films, and the insulating film 508 functions as a second gate insulating film. The insulating film 514 and the insulating film 516 are connected to each other through openings formed therein, and the insulating film 516 is also connected to the insulating film 514 through openings formed therein. and insulating films 506 and 507 functioning as the first gate insulating film and insulating film 5 14 and the insulating film 516 surround the oxide semiconductor film 508.

[0336] By having such a configuration, the oxide semiconductor film 508 included in the transistor 270 can be electrically surrounded by the electric field of the conductive film 504 functioning as the first gate electrode and the oxide conductive film 511b functioning as the second gate electrode. In the case of the transistor 270, a device structure of a transistor in which the oxide semiconductor film in which the channel region is formed is electrically surrounded by the electric fields of the first gate electrode and the second gate electrode can be called a surrounded channel (s-channel) structure.

[0337] Since the transistor 270 has an s-channel structure, an electric field for inducing a channel can be effectively applied to the oxide semiconductor film 508 by the conductive film 504 functioning as the first gate electrode. Therefore, the current driving ability of the transistor 270 is improved, and high ion current characteristics can be obtained. Also, since it is possible to increase the on-current, the transistor 270 can be miniaturized. Further, since the transistor 270 has a <x structure surrounded by the conductive film 504 functioning as the first gate electrode and the oxide conductive film 511b functioning as the second gate electrode, the mechanical strength of the transistor 270 can be increased.

[0338] <Example Configuration 2 of Transistor> FIGS. 23(A) and (B) are cross-sectional views of modified examples of the transistor 270 shown in FIGS. 22(B) and (C). Also, FIGS. 23(C) and (D) are cross-sectional views of modified examples of the transistor 270 shown in FIGS. 22(B) and (C).

[0339] The transistor 270A shown in FIGS. 23A and 23B is the same as the transistor 270 shown in FIGS. 22B and 22C. The oxide semiconductor film 508 included in the transistor 270 has a three-layer structure. The oxide semiconductor film 508 included in the transistor 270A is an oxide semiconductor film 508a , an oxide semiconductor film 508b, and an oxide semiconductor film 508c.

[0340] The transistor 270B shown in FIGS. 23(C) and 23(D) is the same as the transistor 270 shown in FIGS. 22(B) and 22(C). The oxide semiconductor film 508 included in the transistor 270 has a two-layer structure. The oxide semiconductor film 508 included in the transistor 270B is an oxide semiconductor film 508b. and an oxide semiconductor film 508c.

[0341] Here, the band structures of the oxide semiconductor film 508 and the insulating film in contact with the oxide semiconductor film 508 are This will be explained with reference to FIG.

[0342] FIG. 24A shows the insulating film 507, the oxide semiconductor films 508a, 508b, and 508c, and the insulating film 508b. 24(B) is an example of a band structure in the thickness direction of a laminated structure having an insulating film 514. 5 shows a stack of insulating films 507, oxide semiconductor films 508b and 508c, and an insulating film 514. 1 is an example of a band structure in the film thickness direction of the structure. Conductivity of the insulating film 507, the oxide semiconductor films 508a, 508b, and 508c, and the insulating film 514 The energy level (Ec) at the lower band edge is shown.

[0343] In addition, in FIG. 24(A), silicon oxide films are used as insulating films 507 and 514, and oxide semiconductor The metal oxide film 508a has an atomic ratio of In:Ga:Zn=1:1:1.2. The oxide semiconductor film 508b was formed using an oxide semiconductor film formed using a metal target. A metal oxide target with an atomic ratio of metal elements of In:Ga:Zn=4:2:4.1 was used. The oxide semiconductor film 508c is formed by using an oxide semiconductor film formed by the atomic ratio of metal elements The oxide formed using a metal oxide target of In:Ga:Zn=1:1:1.2 FIG. 1 is a band diagram of a configuration using a semiconductor film.

[0344] In addition, in FIG. 24(B), silicon oxide films are used as the insulating films 507 and 514, and oxide semiconductor The metal oxide film 508b has an atomic ratio of In:Ga:Zn=4:2:4.1. The oxide semiconductor film 508c was formed using an oxide semiconductor film formed using a metal target. A metal oxide target with an atomic ratio of In:Ga:Zn=1:1:1.2 was used. FIG. 10 is a band diagram of a structure using an oxide semiconductor film formed by

[0345] As shown in FIGS. 24A and 24B, in the oxide semiconductor films 508a, 508b, and 508c, In other words, the energy level at the bottom of the conduction band changes smoothly. In order to have such a band structure, the oxide The interface between the semiconductor film 508a and the oxide semiconductor film 508b or the interface between the oxide semiconductor film 508b and the oxide semiconductor film 508a At the interface with the oxide semiconductor film 508c, defect levels such as trap centers and recombination centers are formed. Assume that there are no impurities that would cause this to occur.

[0346] In order to form a continuous junction in the oxide semiconductor films 508a, 508b, and 508c, Each film is formed using a multi-chamber film-forming device (sputtering device) equipped with a lock chamber. It is necessary to laminate the layers continuously without exposing them to the air.

[0347] 24A and 24B, the oxide semiconductor film 508b serves as a well. In the transistor using the above stacked structure, the channel region is formed of the oxide semiconductor film 5 It can be seen that it is formed in 08b.

[0348] Note that by providing the oxide semiconductor films 508a and 508c, the oxide semiconductor film 508b This can make trap states that can be formed in the oxide semiconductor film 508b farther away from the oxide semiconductor film 508b.

[0349] In addition, the trap states are at the bottom of the conduction band of the oxide semiconductor film 508b which functions as a channel region. The energy level (Ec) is farther from the vacuum level, and electrons tend to accumulate in the trap level. When electrons accumulate in the trap level, the negative fixed charge This causes a load, and the threshold voltage of the transistor shifts in the positive direction. The trap level is lower than the energy level (Ec) of the conduction band minimum of the oxide semiconductor film 508b. It is preferable to configure the trap level so that the potential is close to the trap level. This makes it difficult for electrons to accumulate, which makes it possible to increase the on-current of the transistor. The field effect mobility can be increased.

[0350] The oxide semiconductor films 508a and 508c have a lower conduction band minimum than the oxide semiconductor film 508b. The energy level of the oxide semiconductor film 508b is close to the vacuum level. and the energy levels of the conduction band minimums of the oxide semiconductor films 508a and 508c. The difference is 0.15 eV or more, or 0.5 eV or more and 2 eV or less, or 1 eV or less. That is, the electron affinity of the oxide semiconductor films 508a and 508c and the The difference in electron affinity from 08b is 0.15 eV or more, or 0.5 eV or more and 2 eV or less , or 1 eV or less.

[0351] With such a structure, the oxide semiconductor film 508b serves as a main current path. That is, the oxide semiconductor film 508b functions as a channel region. The oxide semiconductor film 508a and the oxide semiconductor film 508c function as oxide insulating films. , 508c are metal elements constituting the oxide semiconductor film 508b in which the channel region is formed. Since the oxide semiconductor film is composed of one or more kinds of materials, the oxide semiconductor film 508a and the oxide semiconductor The interface with the conductive film 508b or the interface between the oxide semiconductor film 508b and the oxide semiconductor film 508c Therefore, the movement of carriers is not hindered at the interface. This increases the field effect mobility of the transistor.

[0352] The oxide semiconductor films 508a and 508c function as part of a channel region. To prevent this, a material with sufficiently low electrical conductivity is used. The insulating films 508a and 508c are also called oxide insulating films based on their physical properties and / or functions. In addition, the oxide semiconductor films 508a and 508c have a high electron affinity (vacuum level and conduction the energy level of the oxide semiconductor film 508b is smaller than that of the oxide semiconductor film 508b, and The energy level of the oxide semiconductor film 508b is different from the energy level of the conduction band minimum of the oxide semiconductor film 508b (Band The material used should have a high drain offset. In order to suppress the difference in threshold voltage, the oxide semiconductor films 508a and 508 The energy level of the conduction band minimum of the oxide semiconductor film 508c is equal to the energy level of the conduction band minimum of the oxide semiconductor film 508b. For example, the lower conduction band of the oxide semiconductor film 508b is preferably closer to a vacuum level than to a vacuum level. and the energy levels of the conduction band minimums of the oxide semiconductor films 508a and 508c. The difference between the potentials is preferably 0.2 eV or more, more preferably 0.5 eV or more.

[0353] The oxide semiconductor films 508a and 508c do not contain a spinel crystal structure. It is preferable that the oxide semiconductor films 508a and 508c contain a spinel crystal structure. In this case, the conductive films 512a and 512b are formed at the interface between the spinel crystal structure and other regions. The constituent elements of b may diffuse into the oxide semiconductor film 508b. When the conductive films 508a and 508c are made of CAAC-OS, the conductive films 512a and 512b are made of This is preferable because it increases the blocking property of elements such as copper.

[0354] The thicknesses of the oxide semiconductor films 508a and 508c are determined by the amount of the oxide semiconductor film 508a and the oxide semiconductor film 508c. the insulating film having a thickness larger than that which can suppress diffusion into the oxide semiconductor film 508b; The thickness of the oxide semiconductor film 508b is set to be less than the thickness that prevents oxygen from being supplied from the oxide semiconductor film 514 to the oxide semiconductor film 508b. When the thickness of the oxide semiconductor films 508a and 508c is 10 nm or more, the conductive films 512a and 512b are Diffusion of the constituent elements of the oxide semiconductor film 12b into the oxide semiconductor film 508b can be suppressed. When the thickness of the oxide semiconductor films 508a and 508c is 100 nm or less, the insulating film 514 Therefore, oxygen can be effectively supplied to the oxide semiconductor film 508b.

[0355] In this embodiment, the oxide semiconductor films 508a and 508c are formed using a metal oxide semiconductor film. The metal oxide target was formed with an atomic ratio of In:Ga:Zn=1:1:1.2. However, the present invention is not limited to this. The compound semiconductor films 508a and 508c were made of In:Ga:Zn=1:1:1 [atomic ratio], I n:Ga:Zn=1:3:2[atomic ratio], In:Ga:Zn=1:3:4[atomic ratio] or formed using a metal oxide target of In:Ga:Zn=1:3:6 [atomic ratio] Alternatively, an oxide semiconductor film having a low resistance may be used.

[0356] The oxide semiconductor films 508a and 508c are made of In:Ga:Zn=1:1:1 [atomic When a metal oxide target having a ratio of 1 to 100 is used, the oxide semiconductor films 508a and 508c are In some cases, the relationship is n:Ga:Zn=1:β1(0<β1≦2):β2(0<β2≦3). The oxide semiconductor films 508a and 508c are made of In:Ga:Zn=1:3:4 [atomic When a metal oxide target having a ratio of 1 to 100 is used, the oxide semiconductor films 508a and 508c are In some cases, the relationship is n:Ga:Zn=1:β3(1≦β3≦5):β4(2≦β4≦6). The oxide semiconductor films 508a and 508c are made of In:Ga:Zn=1:3:6 [atomic When a metal oxide target having a ratio of 1 to 100 is used, the oxide semiconductor films 508a and 508c are In some cases, the relationship is n:Ga:Zn=1:β5(1≦β5≦5):β6(4≦β6≦8).

[0357] In addition, the oxide semiconductor film 508 included in the transistor 270 and the transistors 270A and 2 The oxide semiconductor film 508c included in 70B is the conductive film 512a, 512b in the drawing. In other words, a part of the oxide semiconductor film becomes a recess. However, one embodiment of the present invention is not limited to this. The oxide semiconductor film in the region not overlapping with the films 512a and 512b does not necessarily have to have a recess. An example of this case is shown in Figures 25(A) and 25(B). 25A and 25B are cross-sectional views showing an example of the transistor 270 shown above. The oxide semiconductor film 508 in B has a structure without a recess.

[0358] As shown in FIGS. 25C and 25D, the thickness of the oxide semiconductor film 508c is set to 1000 nm by pre-oxidizing the oxide semiconductor film 508a. The oxide semiconductor film 508c and the insulating film 507 are formed thinner than the oxide semiconductor film 508b. An insulating film 519 may be formed over the oxide semiconductor film 508. Openings are formed so that the insulating film 519 c is in contact with the conductive film 512 a and the conductive film 512 b. The insulating film 514 can be formed using the same material and method as the insulating film 514 .

[0359] In addition, the transistor according to this embodiment can be freely combined with each of the above structures. It is possible.

[0360] This embodiment mode can be combined with other embodiment modes as appropriate.

[0361] (Fourth embodiment) In this embodiment, an oxide semiconductor will be described with reference to FIGS.

[0362] <Oxide semiconductor structure> The structure of an oxide semiconductor will be described below.

[0363] Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single-crystal oxide semiconductor, c-axis-aligned oxide semiconductor (CAAC-OS) crystalline oxide semiconductor), polycrystalline oxide Semiconductor, nc-OS (nanocrystalline oxide semiconducting uctor), pseudo-amorphous oxide semiconductor (a-like OS: amorphous-l ike oxide semiconductor) and amorphous oxide semiconductor. .

[0364] From another point of view, oxide semiconductors are classified into amorphous oxide semiconductors and other crystalline oxide semiconductors. Crystalline oxide semiconductors are divided into single-crystal oxide semiconductors, CAAC- Examples include OS, polycrystalline oxide semiconductor, and nc-OS.

[0365] Amorphous structures are generally isotropic and have no heterogeneous structure, and are metastable arrangements of atoms. The bond angles are flexible, and there is short-range order but no long-range order. It is said that...

[0366] That is, the stable oxide semiconductor is completely amorphous. ) and cannot be called an oxide semiconductor. On the other hand, a-li oxide semiconductors cannot be called completely amorphous oxide semiconductors. The ke OS is not isotropic but has an unstable structure with voids. In terms of instability, a-like OS is similar in physical properties to amorphous oxide semiconductors. .

[0367] <caac-os> First, let me explain about CAAC-OS.

[0368] CAAC-OS is an oxide semiconductor having multiple crystal parts (also called pellets) aligned along the c-axis. It is a type of conductor.

[0369] CAAC-OS was analyzed by X-ray diffraction (XRD). For example, the analysis of InGaZnO4, which is classified into the space group R-3m, Structural analysis of crystalline CAAC-OS is performed using the out-of-plane method. As shown in FIG. 26(A), a peak appears at a diffraction angle (2θ) of approximately 31°. The crystal structure is attributed to the (009) plane of the InGaZnO4 crystal. The crystal has a c-axis orientation, and the c-axis is the surface on which the CAAC-OS film is to be formed (also called the surface on which the film is to be formed). It can be seen that the angle is perpendicular to the surface of the sample, or is approximately perpendicular to the surface. In addition to the peaks around 2θ, a peak may also appear around 36°. The peak is due to the crystal structure classified into the space group Fd-3m. It is preferable that the OS does not exhibit such a peak.

[0370] On the other hand, in-pla, X-rays are incident on the CAAC-OS from a direction parallel to the surface to be formed. When structural analysis is performed using the NE method, a peak appears at 2θ around 56°. This peak is due to I The lattice constant is fixed at 2θ around 56°. The analysis (φ scan) is performed by rotating the sample around the normal vector of the sample surface (φ axis). Even if the peak is increased, no clear peak appears, as shown in Figure 26(B). When φ is scanned with 2θ fixed at around 56° for nO4, the results are as shown in Figure 26(C). As shown in Fig. 1, six peaks are observed that are attributed to the crystal plane equivalent to the (110) plane. Structural analysis using RD revealed that the orientation of the a-axis and b-axis of CAAC-OS is irregular. can be confirmed.

[0371] Next, we will explain the CAAC-OS analyzed by electron diffraction. For CAAC-OS with nO4 crystals, a probe was applied parallel to the surface on which the CAAC-OS was formed. When an electron beam with a diameter of 300 nm is incident, a diffraction pattern (control pattern) as shown in FIG. 26(D) is generated. This diffraction pattern may contain In. This includes spots due to the (009) plane of the GaZnO4 crystal. Even in such cases, the pellets contained in the CAAC-OS have a c-axis orientation, and the c-axis is aligned with the surface on which the film is formed. On the other hand, for the same sample, the direction perpendicular to the sample surface The diffraction pattern when an electron beam with a probe diameter of 300 nm was incident directly on the sample is shown in Figure 26(E). A ring-shaped diffraction pattern is confirmed in Figure 26(E). Electron diffraction using an electron beam with a diameter of 300 nm also revealed that the pellets contained in CAAC-OS It can be seen that the a-axis and b-axis of the film do not have any orientation. This is thought to be due to the (010) and (100) planes of the InGaZnO4 crystal. The second ring in Figure 26(E) is thought to be due to the (110) plane. can be.

[0372] In addition, a transmission electron microscope (TEM) A combined analysis image of the bright-field image and diffraction pattern of CAAC-OS was obtained using a microscope. (also called high-resolution TEM image) reveals multiple pellets. On the other hand, even in high-resolution TEM images, the boundaries between pellets, i.e., grain boundaries (grain bows), are not clearly visible. It may not be possible to clearly identify the CAAC It can be said that the -OS is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0373] Figure 27(A) shows a high-resolution T image of a cross section of CAAC-OS observed from a direction approximately parallel to the sample surface. The TEM image shown here is a spherical aberration correction (SAC) image. The spherical aberration correction function was used. A high-resolution TEM image is specifically called a Cs-corrected high-resolution TEM image. For example, an atomic resolution analytical electron microscope JEM-ARM200F manufactured by JEOL Ltd. It can be observed that

[0374] From Figure 27(A), it is possible to confirm the pellet, which is the region where metal atoms are arranged in layers. It has been found that the size of a single pellet can be 1 nm or more, or 3 nm or more. Therefore, the pellets are called nanocrystals (nc). Also, CAAC-OS can be used with CANC (C-Axis Aligned Nano The pellets can also be called oxide semiconductors with CAAC The surface on which the CAAC-OS is formed or the upper surface of the CAAC-OS are formed. It becomes parallel.

[0375] 27(B) and 27(C) show the CAAC- Figures 27(D) and 27(E) show Cs-corrected high-resolution TEM images of the OS surface. These are images obtained by processing the images shown in Figures 27(B) and 27(C). First, let us consider the case where the fast Fourier transform (FFT) of FIG. Then, the FFT image is obtained by performing FFT (Finite Fourier Transform) processing. 2.8 nm based on the origin in the FT image -1 to 5.0 nm -1 The squares that remain between Next, the masked FFT image is subjected to inverse fast Fourier transform (IFFT). The image is processed by using Fast Fourier Transform (FFT). The image obtained in this way is called an FFT filtered image. The ring image is an image in which the periodic component is extracted from a Cs-corrected high-resolution TEM image, and the lattice arrangement is It shows.

[0376] In Figure 27(D), the area where the lattice arrangement is disturbed is indicated by a dashed line. The area surrounded by the dashed line is The area indicated by the broken line is the connection between the pellets. The broken line indicates a hexagonal shape, which indicates that the pellets are hexagonal. The shape of the dot is not limited to a regular hexagon, and is often a non-regular hexagon.

[0377] In FIG. 27(E), a dotted line separates an area with a uniform lattice arrangement from an area with a different uniform lattice arrangement. Even near the dotted line, no clear grain boundaries can be seen. When connecting the surrounding lattice points around a neighboring lattice point, a distorted hexagon, pentagon, or heptagon can be obtained. In other words, the formation of grain boundaries is suppressed by distorting the lattice arrangement. This is because the atomic arrangement of CAAC-OS is not close-packed in the ab-plane direction. The metal element substitution causes the bond distance between atoms to change, resulting in distortion. This is thought to be because it can tolerate

[0378] As described above, the CAAC-OS has a c-axis orientation and multiple crystals in the ab-plane direction. A number of pellets (nanocrystals) are connected to form a distorted crystal structure. AC-OS, CAA crystal(c-axis-aligned ab-pl It can also be called an oxide semiconductor with an anchored crystal. do.

[0379] CAAC-OS is an oxide semiconductor with high crystallinity. CAAC-OS is designed to be free from impurities and defects ( It can also be said to be an oxide semiconductor with few oxygen vacancies.

[0380] The impurities are elements other than the main components of the oxide semiconductor, such as hydrogen, carbon, silicon, and transition metals. For example, oxygen is more likely to be present than metal elements such as silicon that make up oxide semiconductors. Elements with strong bonding strength with the oxide semiconductor remove oxygen from the oxide semiconductor, thereby changing the atomic arrangement of the oxide semiconductor. In addition, heavy metals such as iron and nickel, argon, and niobium Carbon dioxide and other substances have a large atomic radius (or molecular radius), which can disrupt the atomic arrangement of oxide semiconductors. This causes a decrease in crystallinity.

[0381] When an oxide semiconductor has impurities or defects, its characteristics may change due to light, heat, etc. For example, impurities contained in an oxide semiconductor can act as carrier traps or For example, oxygen vacancies in oxide semiconductors can act as carrier traps. In some cases, the SiO 2 can become a carrier generation source by capturing hydrogen.

[0382] CAAC-OS, which has few impurities and oxygen vacancies, is an oxide semiconductor with low carrier density. Specifically, 8 x 10 11 pieces / cm 3 Less than 1 x 10 11 pieces / cm 3 less than, More preferably, 1 × 10 10 pieces / cm 3 Less than 1 x 10 -9 pieces / cm 3 The above Such an oxide semiconductor can be a high-purity intrinsic oxide semiconductor. CAAC-OS has a low impurity concentration and The density of defect states is low, that is, the oxide semiconductor has stable characteristics.

[0383] <nc-os> Next, we will explain nc-OS.

[0384] We will explain the case where nc-OS is analyzed by XRD. For example, When structural analysis is performed using the out-of-plane method, no peaks indicating orientation appear. That is, the crystals of nc-OS do not have any orientation.

[0385] For example, an nc-OS having InGaZnO4 crystals was thinned to a thickness of 34 nm. When an electron beam with a probe diameter of 50 nm is incident on the region in parallel to the surface to be formed, the A ring-shaped diffraction pattern (nanobeam electron diffraction pattern) as shown in (A) was observed. In addition, the diffraction pattern (nano) when an electron beam with a probe diameter of 1 nm is incident on the same sample. The electron diffraction pattern (B) is shown in Figure 28(B). Therefore, nc-OS has a probe diameter of 50 nm. Although the order is not confirmed by irradiating an electron beam, the order is confirmed by irradiating an electron beam with a probe diameter of 1 nm. By projecting the images, order is confirmed.

[0386] In addition, when an electron beam with a probe diameter of 1 nm is incident on an area with a thickness of less than 10 nm, As shown in Figure 28(C), an electron diffraction pattern was observed in which the spots were arranged in a roughly regular hexagonal shape. Therefore, in the range of thickness less than 10 nm, the nc-OS is ordered. It can be seen that the crystals are oriented in various directions. Therefore, there are some areas where no regular electron diffraction pattern is observed.

[0387] FIG. 28(D) shows the Cs-corrected high-resolution image of the cross section of nc-OS observed from a direction approximately parallel to the surface on which the film was formed. The nc-OS is shown in the high-resolution TEM image, with the areas indicated by the auxiliary lines. There are two areas where crystals can be seen, as shown in Fig. 1, and areas where no clear crystals can be seen. The crystal part contained in the nc-OS has a size of 1 nm to 10 nm. In particular, the size is often between 1 nm and 3 nm. An oxide semiconductor having a size of more than 0 nm and not more than 100 nm is called a microcrystalline oxide semiconductor (microcrystalline oxide semiconductor). It is sometimes called a crystalline oxide semiconductor. For example, in the case of nc-OS, the grain boundaries may not be clearly visible in high-resolution TEM images. It is possible that the nanocrystals originate from the same source as the pellets in CAAC-OS. Therefore, the crystalline part of the nc-OS may be referred to as a pellet below.

[0388] In this way, the nc-OS can be used in a microscopic area (e.g., an area of ​​1 nm or more and 10 nm or less, especially The atomic arrangement is periodic in the region of 1 nm to 3 nm. Therefore, no regularity in the crystal orientation is observed between different pellets. Therefore, depending on the analytical method, nc-OS may be classified as a-like OS or amorphous OS. It may be difficult to distinguish it from an oxide semiconductor.

[0389] Since the crystal orientation between the pellets (nanocrystals) is not regular, nc-OS is Oxide with RANC (Random Aligned nanocrystals) Semiconductor or NANC (Non-Aligned nanocrystals) It can also be called an oxide semiconductor.

[0390] The nc-OS is an oxide semiconductor with higher order than an amorphous oxide semiconductor. nc-OS has a lower defect state density than a-like OS and amorphous oxide semiconductors. However, there is no regularity in the crystal orientation between different pellets in nc-OS. , the nc-OS has a higher density of defect states than the CAAC-OS.

[0391] <a-like OS> The a-like OS is an oxide semiconductor with a structure between the nc-OS and amorphous oxide semiconductor. It is a conductor.

[0392] Figure 29 shows a high-resolution cross-sectional TEM image of the a-like OS. This is a high-resolution cross-sectional TEM image of the a-like OS at the start of electron irradiation. ) is 4.3 × 10 8 e - / nm 2 electrons (e - ) High a-like OS after irradiation 29(A) and 29(B) show that the a-like OS is It can be seen that from the start of electron irradiation, striped bright regions extending in the vertical direction are observed. It can be seen that the bright areas change shape after electron irradiation. It is estimated to be the area.

[0393] Because of the porosity, the a-like OS has an unstable structure. To demonstrate that the OS has a less stable structure than the CAAC-OS and nc-OS, This shows the structural changes caused by electron irradiation.

[0394] As samples, a-like OS, nc-OS, and CAAC-OS were prepared. The sample is also an In-Ga-Zn oxide.

[0395] First, high-resolution cross-sectional TEM images of each sample are acquired. Each of these has a crystalline portion.

[0396] The unit cell of the InGaZnO4 crystal has three In-O layers and a Ga-Zn- It is known that it has a structure in which a total of nine layers, including six O layers, are stacked in layers along the c-axis. The spacing between these adjacent layers is the same as the lattice spacing (also called the d value) of the (009) plane. The value is estimated to be 0.29 nm from crystal structure analysis. Below, the area where the lattice spacing is between 0.28 nm and 0.30 nm is InGaZn The lattice fringes correspond to the ab plane of the InGaZnO4 crystal. do.

[0397] Figure 30 shows an example of investigating the average size of the crystal parts (22 to 30 locations) of each sample. The length of the lattice fringes mentioned above is the size of the crystal part. The crystal part of the OS grows in size according to the cumulative amount of electron irradiation used to obtain the TEM image. From Figure 30, it can be seen that in the early stages of TEM observation, the size of the particles was about 1.2 nm. The crystal part (also called the initial nucleus) that was - ) cumulative exposure is 4.2 × 10 8 e - / nm 2 On the other hand, in the case of nc, the size of the crystals grows to about 1.9 nm. The cumulative electron irradiation dose for the -OS and CAAC-OS was 4.2 × 10 8 e - / nm 2 It can be seen that there is no change in the size of the crystals within the range of Regardless of the cumulative electron irradiation dose, the size of the crystalline parts of the nc-OS and CAAC-OS crystals was The thicknesses are approximately 1.3 nm and 1.8 nm, respectively. The observation of M was performed using a Hitachi transmission electron microscope H-9000NAR. The electron beam irradiation conditions were: The voltage was 300 kV and the current density was 6.7 × 10 5 e - / (nm 2 s), the diameter of the irradiated area The wavelength was set to 230 nm.

[0398] In this way, the growth of crystalline parts can be observed in a-like OS due to electron irradiation. On the other hand, the nc-OS and CAAC-OS hardly show any growth of crystals due to electron irradiation. In other words, a-like OS is less likely to cause anxiety than nc-OS and CAAC-OS. It can be seen that it has a stable structure.

[0399] In addition, due to its porosity, a-like OS has a It is a low-density structure. Specifically, the density of a-like OS is The density of nc-OS and CAAC-O is 78.6% or more and less than 92.3%. The density of S is 92.3% or more but less than 100% of the density of a single crystal of the same composition. It is difficult to form a film of an oxide semiconductor having a conductivity of less than 78%.

[0400] For example, in an oxide semiconductor with an atomic ratio of In:Ga:Zn=1:1:1, The density of single-crystal InGaZnO4 with a rhombohedral crystal structure is 6.357 g / cm 3 That is it. For example, in an oxide semiconductor that satisfies the atomic ratio of In:Ga:Zn=1:1:1, , the density of a-like OS is 5.0 g / cm 3 Less than 5.9 g / cm 3 In addition, for example, in an oxide semiconductor satisfying In:Ga:Zn = 1:1:1 [atomic ratio], the density of nc-OS and the density of CAAC-OS are 5.9 g / cm 3 or more and 6.3 g / cm 3 not satisfied.

[0401] In addition, when there is no single crystal of the same composition, by combining single crystals with different compositions at an arbitrary ratio, the density corresponding to the single crystal in the desired composition can be estimated. The density corresponding to the single crystal of the desired composition may be estimated using the weighted average with respect to the ratio of combining single crystals with different compositions. However, it is preferable to estimate the density by combining as few types of single crystals as possible. As described above, the oxide semiconductor has various structures and each has various characteristics. In addition, the oxide semiconductor may be, for example, a laminated film having two or more of amorphous oxide semiconductor, a-like OS, nc-OS, CAAC-OS.

[0402] This embodiment can be appropriately combined with other embodiments.

[0403]

[0404] (Embodiment 5) <Configuration of CAC> Hereinafter, the configuration of CAC (Cloud Aligned Complementary)-OS that can be used in one aspect of the present invention will be described.

[0405] CAC is, for example, a configuration of a material in which the elements constituting the oxide semiconductor are unevenly distributed in a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof. In the following, it is assumed that one or more metal elements are unevenly distributed in an oxide semiconductor. The region having the metal element is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less A state in which the particles are mixed in a size similar to or close to this size is also called a mosaic or patch state.

[0406] For example, CAC-IGZ in In-Ga-Zn oxide (hereinafter also referred to as IGZO) O is indium oxide (hereinafter referred to as InO X1 (X1 is a real number greater than 0.) or indium zinc oxide (hereinafter referred to as In X2 Zn Y2 O Z2 (X2, Y2, and Z2 are ) and gallium oxide (GaO X3 (X3 is from 0 ) or gallium zinc oxide (Ga X4 Zn Y4 O Z4 ( X4, Y4, and Z4 are real numbers greater than 0.) The mosaic pattern is formed by InO X1 or In X2 Zn Y2 O Z2 But in the membrane It is a uniformly distributed configuration (hereinafter also referred to as a cloud-like configuration).

[0407] In other words, CAC-IGZO is GaO X3 The region where In is the main component and X2 Zn Y2 O Z 2 or InO X1 A composite oxide semiconductor having a structure in which a region in which In this specification, for example, the number of In atoms relative to the element M in the first region is The ratio of the number of atoms of In to the element M in the first region is greater than the ratio of the number of atoms of In to the element M in the second region. It is assumed that the concentration of In is higher than that of the second region.

[0408] IGZO is a common name and refers to a compound of In, Ga, Zn, and O. A typical example is InGaO3(ZnO) m1 (m1 is a natural number) or In (1+ x0) Ga (1-x0) O3(ZnO) m0 (-1≦x0≦1, m0 is an arbitrary number) Examples of such crystalline compounds include:

[0409] The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a structure in which multiple IGZO nanocrystals have a c-axis orientation and, in the ab plane, It is a non-oriented, connected crystal structure.

[0410] On the other hand, CAC refers to the material composition. CAC is a material containing In, Ga, Zn, and O. In the structure, there are areas where Ga is the main component and areas where In is the main component. The nanoparticle-like regions, which are the main component, are randomly dispersed in a mosaic pattern. Therefore, the crystal structure is a secondary element in CAC.

[0411] Note that CAC does not include a laminated structure of two or more films with different compositions. However, this does not include a structure consisting of two layers, one containing In as the main component and the other containing Ga as the main component.

[0412] In addition, GaO X3 The region where In is the main component and X2 Zn Y2 O Z2 or InO X1 Mainly The region that is a component may not have a clearly observable boundary.

[0413] <Analysis of CAC-IGZO> Subsequently, using various measurement methods, the results of measuring the oxide semiconductor formed on the substrate are described below.

[0414] ≪Sample Composition and Fabrication Method≫ Hereinafter, nine samples according to one aspect of the present invention will be described. Each sample is an oxide semiconductor fabricated under conditions where the substrate temperature and the oxygen gas flow rate ratio are different when forming the film. Note that each sample has a structure having a substrate and an oxide semiconductor on the substrate, respectively.

[0415] The fabrication method of each sample will be described.

[0416] First, a glass substrate is used as the substrate. Subsequently, using a sputtering apparatus, In-Ga-Zn oxide with a thickness of 100 nm is formed as an oxide semiconductor on the glass substrate. The film formation conditions are such that the pressure in the chamber is 0.6 Pa, and an oxide target ( In:Ga:Zn = 4:2:4.1 [atomic ratio]) is used for the target. Also, 2500 W of AC power is supplied to the oxide target installed in the sputtering apparatus. The AC power supply to the oxide target installed in the sputtering apparatus is 2500 W.

[0417] Note that as the conditions for forming the oxide film, the substrate temperature is set to a temperature that is not intentionally heated (hereinafter also referred to as R.T.), 130 °C, or 170 °C. Also, the flow rate ratio of oxygen gas to the mixed gas of Ar and oxygen (hereinafter also referred to as the oxygen gas flow rate ratio) is set to 10%, 30%, or 100% to fabricate nine samples. By setting the flow rate ratio of oxygen gas to the mixed gas of Ar and oxygen (hereinafter also referred to as the oxygen gas flow rate ratio) to 10%, 30%, or 100%, nine samples are fabricated.

[0418] <00030​​In this section, we will explain the results of XRD measurements on nine samples. The D device used was the D8 ADVANCE manufactured by Bruker. The scanning range is 15° to 50° using the -of-plane θ / 2θ scan. For example, the step width was 0.02 deg. and the scanning speed was 3.0 deg. / min.

[0419] FIG. 36 shows the results of measuring the XRD spectrum using the out-of-plane method. In addition, in FIG. 36, the upper part shows the measurement results for a sample where the substrate temperature during film formation was 170°C. As a result, the middle row shows the measurement results for a sample with a substrate temperature of 130°C during film formation, and the bottom row shows the measurement results for a sample with a substrate temperature of 130°C during film formation. The left column shows the measurement results for samples with a substrate temperature of RT. The center column shows the measurement results for the sample with a flow rate ratio of 10%. The center column shows the measurement results for the sample with a flow rate ratio of 3%. The right column shows the measurement results for the sample with a 0% oxygen gas flow rate, and the right column shows the measurement results for the sample with a 100% oxygen gas flow rate. The measurement results are shown below.

[0420] The XRD spectrum shown in FIG. 36 shows that the increase in the substrate temperature during film formation or the decrease in the amount of oxygen during film formation Increasing the gas flow rate ratio increases the peak intensity around 2θ=31°. The peak at 2θ=31° indicates that the c-axis is oriented in the direction approximately perpendicular to the surface on which the film is formed or the upper surface. Crystalline IGZO compound (CAAC(c-axis aligned crystallization) It is also called ine)-IGZO. ) is known to be derived from the fact that

[0421] In addition, the XRD spectrum shown in FIG. 36 shows that the substrate temperature during film formation was low or the oxygen gas flow The smaller the ratio of the amount of SiO2, the less clear the peak. In the case of a sample with a small oxygen gas flow rate, the orientation of the ab plane direction and the c axis direction of the measurement area is I know I can’t see it.

[0422] <Analysis by electron microscope> In this section, the samples were prepared at a substrate temperature of RT and an oxygen gas flow rate of 10% during film formation. HAADF(High-Angle Annular Dark Field)-STE M(Scanning Transmission Electron Microsc The results of the observation and analysis using HAADF-STE are described below (hereafter referred to as HAADF-STE). Images obtained by M are also called TEM images.

[0423] Planar images obtained by HAADF-STEM (hereinafter also referred to as planar TEM images), and The results of image analysis of the cross-sectional image (hereinafter also referred to as the cross-sectional TEM image) will be explained. The TEM images were observed using a spherical aberration correction function. The images were taken using an atomic resolution analytical electron microscope JEM-ARM200F manufactured by JEOL Ltd. The electron beam was irradiated at an acceleration voltage of 200 kV with a beam diameter of approximately 0.1 nmφ.

[0424] FIG. 37(A) shows a sample fabricated at a substrate temperature of RT and an oxygen gas flow rate of 10% during film formation. FIG. 37(B) shows the relationship between the substrate temperature RT and the oxygen gas flow rate during film formation. This is a cross-sectional TEM image of a sample prepared at a ratio of 10%.

[0425] <Electron diffraction pattern analysis> In this section, the sample was prepared at a substrate temperature of RT and an oxygen gas flow rate of 10% during film formation. By irradiating an electron beam with a probe diameter of 1 nm (also called a nanobeam electron beam), The results of obtaining the diffraction patterns will now be described.

[0426] As shown in FIG. 37(A), the film was formed at a substrate temperature of RT and an oxygen gas flow rate of 10%. In the planar TEM image of the sample, black spots a1, a2, a3, a4, and a5 The electron beam diffraction pattern shown in the figure is observed. The sunspot a1 is moved from the 0-second position to the 35-second position at a constant speed while shooting. The results of black point a1 are shown in Figure 37(C), the results of black point a2 are shown in Figure 37(D), and the results of black point a3 are shown in Figure 37(E). The results for black point a4 are shown in FIG. 37(F), and the results for black point a5 are shown in FIG. 37(G).

[0427] From Figure 37(C), Figure 37(D), Figure 37(E), Figure 37(F), and Figure 37(G), A bright area can be observed that resembles a ring. Spots can be observed.

[0428] Also, as shown in FIG. 37(B), the film was formed at a substrate temperature of RT and an oxygen gas flow rate of 10%. In the cross-sectional TEM image of the prepared sample, black spots b1, b2, b3, b4, and Observe the electron diffraction pattern indicated by point b5. The results for black point b1 are shown in Figure 37(H), and the results for black point b2 are shown in Figure 37(H). The results of black point b3 are shown in Figure 37(J), and the results of black point b4 are shown in Figure 37(K). The results for black point b5 are shown in Figure 37(L).

[0429] From Figure 37(H), Figure 37(I), Figure 37(J), Figure 37(K), and Figure 37(L), A ring-shaped area with high brightness can be observed. Also, multiple spots can be observed in the ring-shaped area. Cut.

[0430] Here, for example, for a CAAC-OS having InGaZnO4 crystals, When an electron beam with a probe diameter of 300 nm is incident on the InGaZnO4 crystal, ) planes. It is clear that the film has a c-axis orientation, and the c-axis is oriented in a direction substantially perpendicular to the surface on which the film is formed or the upper surface. On the other hand, an electron beam with a probe diameter of 300 nm is incident perpendicularly to the sample surface. In other words, CAAC-OS has a ring-shaped diffraction pattern. It can be seen that the film has no orientation.

[0431] In addition, oxide semiconductors having microcrystals (nano crystalline oxide semiconductor. Hereafter referred to as nc-OS.) For example, when electron diffraction is performed using an electron beam of 50 nm or more, a halo pattern is observed. In addition, a small probe diameter electron beam (e.g. When nanobeam electron diffraction is performed using a material with a thickness of less than 50 nm, bright spots are observed. In addition, when nanobeam electron diffraction is performed on nc-OS, a circular (ring-shaped) structure is observed. ) A bright area may be observed. In addition, multiple bright spots may be observed in a ring-shaped area. This may be the case.

[0432] The electron diffraction pattern of the sample prepared at the substrate temperature RT and oxygen gas flow rate ratio of 10% during film formation. The ring has a ring-shaped area with high brightness and multiple bright spots in the ring area. The sample fabricated at a substrate temperature of RT and an oxygen gas flow rate of 10% during deposition had an electron diffraction pattern. The layer becomes nc-OS, and has no orientation in the planar direction or cross-sectional direction.

[0433] From the above, an oxide semiconductor formed at a low substrate temperature or a low oxygen gas flow rate ratio has the following properties: It is clearly different from both an oxide semiconductor film with an amorphous structure and an oxide semiconductor film with a single crystal structure. It can be assumed that it has the properties.

[0434] ≪Elemental analysis≫ In this article, we will discuss energy dispersive X-ray spectroscopy (EDX). EDX mapping was obtained and evaluated using X-ray spectroscopy. By doing so, the sample was fabricated at a substrate temperature of RT and an oxygen gas flow rate of 10% during film formation. The results of elemental analysis of the material are explained below. An energy dispersive X-ray analyzer JED-2300T manufactured by JEOL Ltd. is used. A Si drift detector is used to detect the X-rays emitted from the sample.

[0435] In EDX measurement, each point in the analysis area of ​​the sample is irradiated with an electron beam, and the resulting The energy and frequency of characteristic X-rays of the material are measured, and an EDX spectrum corresponding to each point is obtained. In this embodiment, the peaks in the EDX spectrum at each point are determined as electron transitions to the L shell of the In atom. , electron transition to the K shell of Ga atom, electron transition to the K shell of Zn atom, and electron transition to the K shell of O atom The ratio of each atom at each point is calculated. By performing EDX analysis on a region, it is possible to obtain EDX mapping that shows the distribution of the ratio of each atom. This can be done.

[0436] Figure 38 shows the cross section of a sample fabricated at a substrate temperature of RT and an oxygen gas flow rate of 10% during film formation. FIG. 38(A) shows EDX mapping of Ga atoms (all The ratio of Ga atoms to Ga atoms is in the range of 1.18 to 18.64 [atomic%]. ) Figure 38(B) shows the EDX mapping of In atoms (the ratio of In atoms to all atoms). The ratio is in the range of 9.28 to 33.74 [atomic%]. ) shows EDX mapping of Zn atoms (ratio of Zn atoms to total atoms is 6.69 to 24 0.99 [atomic%] range.) Also, Figure 38(A) and Figure 38(B) 38(C) and 38(D) are fabricated at a substrate temperature of RT and an oxygen gas flow rate of 10% during film formation. The cross section of the sample shows the same area. The more the measured element, the brighter it becomes, and the less the measured element, the darker it becomes. The magnification of the EDX mapping shown in Figure 38 is 7.2 million times. do.

[0437] In the EDX mapping shown in Figures 38(A), 38(B), and 38(C), The film was formed at a substrate temperature of RT and an oxygen gas flow rate of 10%. In the prepared sample, it can be seen that each atom exists with a distribution. 38(A), 38(B), and 38(C) are enclosed by solid lines and dashed lines. Pay attention.

[0438] In Figure 38(A), the area enclosed by the solid line contains many relatively dark areas, and the area enclosed by the dashed line contains many relatively dark areas. , contains many relatively bright areas. In addition, the area enclosed by the solid line in Figure 38(B) contains many relatively bright areas. The area surrounded by the dashed line contains many bright areas, while the area surrounded by the dashed line contains many relatively dark areas.

[0439] In other words, the area surrounded by the solid line is the area where the In atoms are relatively abundant, and the area surrounded by the dashed line is the area where the In atoms are relatively abundant. In Figure 38(C), in the area surrounded by the solid line, The right side is a relatively bright area, and the left side is a relatively dark area. The range is In X2 Zn Y2 O Z2 , or InO X1 This is the area where the main components are:

[0440] The area surrounded by the solid line is the area where the number of Ga atoms is relatively small, and the area surrounded by the dashed line is the area where the number of Ga atoms is relatively small. In Figure 38(C), the area surrounded by the dashed line is the upper left area. The upper right area is a relatively bright area, and the lower right area is a relatively dark area. The area enclosed by the dashed line is GaO X3 , or Ga X4 Zn Y4 O Z4 Areas where the main components are is.

[0441] Also, from Figures 38(A), 38(B), and 38(C), the distribution of In atoms is similar to that of Ga atoms. The distribution is relatively uniform compared to the InO X1 The region where is the main component is In X2 Z n Y2 O Z2 It appears to be connected to each other through the area where In this way, X2 Zn Y2 O Z2 , or InO X1 The region where is the main component is the cluster. It is formed in a bamboo-like shape.

[0442] Thus, GaO X3 The region where In is the main component and X2 Zn Y2 O Z2 , or InO X1 In-Ga-Zn oxide with a structure in which the regions in which The material can be called CAC-IGZO.

[0443] The crystal structure of CAC is an nc structure. The nc structure of CAC is In the X-ray diffraction pattern, bright spots originating from IGZO including single crystal, polycrystalline, and CAAC structures In addition to the spot, there are several bright spots. In addition to the bright spots, the crystal structure is defined as a ring-shaped area of ​​high brightness. do.

[0444] Also, from Figures 38(A), 38(B), and 38(C), GaO X3 is the main component Area, and In X2 Zn Y2 O Z2 , or InO X1 The size of the region where is the principal component is The observed size is 0.5 nm or more and 10 nm or less, or 1 nm or more and 3 nm or less. In EDX mapping, the diameter of the area where each metal element is the main component is 1 nm or more. nm or less.

[0445] From the above, CAC-IGZO has a structure different from that of IGZO compounds in which metal elements are uniformly distributed. CAC-IGZO has a structure different from that of IGZO compounds. X3 The region where In is the main component. X2 Zn Y2 O Z2 , or InO X1 is the main component The structure is such that the regions with each element as the main component are separated into phases, forming a mosaic. Therefore, when CAC-IGZO is used in a semiconductor device, GaO X3 Due to factors such as Properties and In X2 Zn Y2 O Z2 , or InO X1 The properties resulting from this act in a complementary manner. This results in a high on-state current (I on ) and high field-effect mobility (μ) This can be done.

[0446] In addition, semiconductor devices using CAC-IGZO are highly reliable. O is ideal for a variety of semiconductor devices, including displays.

[0447] This embodiment mode can be combined with other embodiment modes as appropriate.

[0448] (Embodiment 6) In this embodiment, a touch panel module including an input / output device according to one embodiment of the present invention and a power supply The child devices will be described with reference to FIGS.

[0449] The touch panel module 8000 shown in FIG. 31 includes an upper cover 8001 and a lower cover 8002. Between the FPC8003 and the frame 8009, there is a touch panel 8004 connected to the FPC8003. It includes a printed circuit board 8010 and a battery 8011 .

[0450] The input / output device of one embodiment of the present invention can be used for the touch panel 8004, for example.

[0451] The upper cover 8001 and the lower cover 8002 are designed to fit the size of the touch panel 8004. The shape and dimensions can be changed as needed.

[0452] When a transmissive liquid crystal element is used, the backlight 8007 is The backlight 8007 has a light source 8008. Although the configuration in which the light source 8008 is disposed above the backlight 8007 has been illustrated, the present invention is not limited to this. For example, a light source 8008 may be arranged at the end of the backlight 8007, and a light diffusion layer may be arranged. A diffused plate may be used. When a self-luminous light-emitting element such as an organic EL element is used, In the case of a reflective panel, the backlight 8007 is not provided. Good too.

[0453] The frame 8009 protects the touch panel 8004 and also prevents the movement of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the operation of the The frame 8009 may also function as a heat sink.

[0454] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply to the power supply circuit can be an external commercial power supply or Alternatively, the power source may be a separately provided battery 8011. This can be omitted if a commercial power source is used.

[0455] In addition, the Touch Panel 8004 uses additional components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided as follows.

[0456] 32(A) to 32(H) and 33 are diagrams showing electronic devices. These electronic devices are Body 5000, display unit 5001, speaker 5003, LED lamp 5004, operation key 50 05 (including a power switch or an operation switch), a connection terminal 5006, a sensor 5007 ( Force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances , sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, 5008, a microphone 5009, etc. can.

[0457] FIG. 32(A) shows a mobile computer, which includes, in addition to the above, a switch 5009, It may have an infrared port 5010, etc. FIG. 32(B) shows a portable device equipped with a recording medium. A type of image reproducing device (for example, a DVD reproducing device), which, in addition to the above, also has a second display 32C shows a TV. In addition to the above, the device may also include a stand 5012. The television device can be operated using an operation switch provided on the housing 5000 or a separate remote control. This can be done by operating the operating device 5013. The channel and volume can be controlled by the In addition, the remote control operation device 5013 can be A display unit for displaying output information may be provided. In addition to the above, the system may also include a recording medium reading unit 5011. 2(E) is a digital camera with a television receiving function, and in addition to the above, it also has an antenna 5 32, the camera may have a shutter button 5014, a shutter release button 5015, an image receiving unit 5016, etc. (F) is a portable gaming machine, and in addition to the above, it has a second display unit 5002, a recording medium reading 32(G) shows a portable television receiver, In addition to the above, it may have a charger 5017 capable of transmitting and receiving signals, etc. FIG. 32(H) shows a wristwatch type information terminal, which includes, in addition to the above, a band 5018, a clasp, and the like. The display mounted on the housing 5000, which also serves as a bezel, may have a gold 5019 or the like. The display unit 5001 has a non-rectangular display area. 33A shows the display of the device. Digital Signage (electronic signage). Figure 33(B) is a digital signage mounted on a cylindrical pillar.

[0458] The electronic devices shown in FIGS. 32(A) to 32(H) and 33 can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Panel function, calendar, date or time display function, various software ( It has a function to control processing by a program, a wireless communication function, and various controls using the wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, The function of receiving, reading out the program or data recorded on the recording medium and displaying it on the display Furthermore, in an electronic device having multiple display units, In this case, one display section is used mainly to display image information, and another display section is used mainly to display text information. or a function to display images that take parallax into account on multiple displays to create a three-dimensional image. Furthermore, in electronic devices having an image receiving unit, It has the functions of taking still images, taking videos, and correcting the images automatically or manually. function to save the captured images to a recording medium (external or built-in to the camera); It is possible to have a function to display an image on the display unit. The functions that the electronic device shown in FIG. 33 can have are not limited to these, and it may have various functions. It is possible.

[0459] The electronic device of this embodiment is characterized by having a display unit for displaying some information. The input / output device of one embodiment of the present invention can be applied to the display portion.

[0460] This embodiment mode can be combined with other embodiment modes as appropriate. [Example]

[0461] In this example, an input / output device according to one embodiment of the present invention will be described.

[0462] First, the specifications of the input / output device of this embodiment will be explained. The size is 4.3 inches diagonally. The effective pixel count is 1080(H) x 1920(V) FHD (Full High Definition) The pixel size was 49.5 μm (H) × 49.5 μm (V). The panel dimensions are 69.76mm (H) x 141.4mm (V). The sensor area was 53.46mm (H) × 95.04mm (V). The transistor has an oxide semiconductor in the channel formation region. An E (channel etch) type transistor was used.

[0463] The input / output device of this embodiment can function as a transmissive liquid crystal display device. The liquid crystal element used was a FFS mode liquid crystal element. The aperture ratio was set to 48.0%. The driving frequency was 60Hz. The video signal format used was analog line sequential.

[0464] The gate driver is built-in, and the source driver uses COF.

[0465] The detection element is a projected capacitance type (mutual capacitance type). The common electrode of the liquid crystal element is The number of sensor units was 18 (H) x 32 (V). Specifically, there are 32 conductive films 56a and 18 conductive films 58 in FIG. The size of one sensor unit is 2.970 mm x 2.970 mm. One conductive film 56b in (A) has a size of 30×60 pixels. The conductive film 56a has a size equivalent to 30×1080 pixels.

[0466] One frame period shown in FIG. 8(E) is 16.667 ms, and the writing period is 8.33 3 ms, and the two detection periods are 4.167 ms each.

[0467] The cross-sectional schematic diagram of the input / output device of this embodiment corresponds to FIG. 1B. For details, see Embodiment 1. can.

[0468] A glass substrate with a thickness of about 0.7 mm was used for the substrate 211. A glass substrate with a thickness of about 0. A glass substrate having a thickness of 1 mm, about 0.2 mm, or about 0.3 mm was used. The gate electrode 221 was The insulating film 213 has a laminated structure of a tungsten nitride film and a copper film. The oxide semiconductor film 223 has a stacked structure of a silicon dioxide film and a silicon dioxide film. The oxide semiconductor film 223 is made of a metal element having a different atomic ratio. The two layers were formed using the sputtering targets, and the total thickness of the two layers was The oxide semiconductor film 223 and the oxide conductive film 227 were formed of In-G The oxide conductive film 227 was formed using α-Zn oxide. The oxide conductive film 227 had a single layer structure and a thickness of about The source electrode 225a and the drain electrode 225b are made of a tungsten film. The insulating film 215 has a stacked structure of an aluminum film and a titanium film. The insulating film 217 was a silicon nitride film. The insulating film 219 was an acrylic film. The conductive film 251 and the conductive film 252 were each made of silicon with a thickness of about 100 nm. An indium tin oxide film containing tetrachloromethane was used. A silicon nitride film was used for the insulating film 253. A negative liquid crystal was used for the substrate 249. Also, a polarized film with a thickness of about 200 μm was placed on the surface of the substrate 261. In this example, an APC film having a thickness of about 100 nm was used for the conductive film 255. Two types of input / output devices were fabricated: one using a Ti film and the other using Ti with a thickness of approximately 200 nm.

[0469] Figure 35 is a photograph showing the display state of the input / output device of this example. The right and top sides (not shown) of the input / output connectors are connected to FPCs. In the power device, a glass substrate with a thickness of about 0.3 mm was used as the substrate 261. As shown in FIG. 35, an APC having a thickness of about 100 nm was used for the substrate 5. By using this, we were able to create an input / output device that can display images well. The input / output device shown has good detection sensitivity of the touch sensor and is capable of simultaneous multi-point detection. .

[0470] The striped display marks are arranged at intervals approximately equal to the width of the conductive film 56a (the length in the Y direction in FIG. 9(A)). Therefore, the parasitic capacitance of the conductive film 56a and the conductive film 56b is made equal to each other. After the change, the width of one conductive film 56b is 2 The size of each conductive film 56a is equivalent to 1×60 pixels, and one conductive film 56a is equivalent to 39×1080 pixels. As a result, the resistance value of the conductive film 56b is reduced from 1.66 kΩ to 1.19 kΩ. As a result, the capacitance of the conductive film 56b changed from 534 pF to 674 pF. The value of the resistance value of the conductive film 56a is changed from 0.86 kΩ to 1.35 kΩ, and the capacitance of the conductive film 56a is changed from 930 pF to 68 pF. By making the parasitic capacitance of the conductive film 56a and the conductive film 56b uniform, the display unevenness can be reduced. The touch sensing signal is transmitted to the conductive film 56. When the voltage is alternately input to the conductive film 56a and the conductive film 56b, Display unevenness was reduced, and a better display was achieved. [Explanation of symbols]

[0471] 56 Conductive film 56a Conductive film 56b Conductive film 57a Auxiliary wiring 57b Auxiliary wiring 58 Conductive Film 60 pixels 60a subpixel 60b subpixel 60c subpixel 106 insulating film 107 Insulating film 114 insulating film 116 Insulating film 141 Aperture 142 Aperture 193 Target 194 Plasma 201a Transistor 201b Transistor 201c transistor 203 Transistor 203a Transistor 203b Transistor 205a Connection 205b Connection 207 Liquid crystal element 207a Liquid crystal element 207b Liquid crystal element 211 Substrate 213 Insulating film 215 insulating film 217 Insulating Film 218 Insulating film 219 Insulating Film 221 Gate electrode 223 Oxide semiconductor film 225a Source electrode 225b Drain electrode 226 Conductive Film 227 Oxide Conductive Film 227a Oxide semiconductor film 231 Conductive Film 233 Conductive Film 235 Conductive Film 241 Colored film 243 Light-shielding film 245 insulating film 247 Spacer 249 LCD 251 Conductive film 252 Conductive film 253 Insulating Film 254 Conductive film 255 Conductive Film 257 Connections 259 FPC 261 Circuit Board 265 Adhesive layer 267 Connections 268 IC 269 ​​FPC 270 transistors 270A transistor 270B transistor 273 pixels 275 Conductive Film 277 areas 300 I / O devices 301 Display section 302 Scanning line driving circuit 303 pixels 502 board 504 Conductive film 506 Insulating film 507 Insulating film 508 Oxide semiconductor film 508a Oxide semiconductor film 508b Oxide semiconductor film 508c Oxide semiconductor film 511a Oxide semiconductor film 511b Oxide conductive film 512a Conductive film 512b Conductive film 514 Insulating film 516 Insulating film 518 Insulating film 519 Insulating Film 552a opening 552b opening 552c opening 3501 Wiring 3502 Wiring 3503 Transistor 3504 Liquid crystal elements 3510 Wiring 3510_1 Wiring 3510_2 Wiring 3511 Wiring 3515_1 Block 3515_2 Block 3516 blocks 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared port 5011 Recording medium reading unit 5012 Stand 5013 Remote control device 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 5018 Band 5019 Clasp 5020 Icon 5021 Icon 6500 Touch Panel Module 6501 Circuit Unit 6502 Signal line driver circuit 6503 Sensor driver circuit 6504 detection circuit 6505 timing controller 6506 Image processing circuit 6510 Touch Panel 6511 Display section 6512 input section 6513 Scanning line driver circuit 6520 IC 6530 IC 6531 Circuit Board 6532 Opposing substrate 6533 FPC 6534 PCB 6540 CPU 8000 Touch Panel Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8007 Backlight 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

1. A liquid crystal display device having a detection element, A first conductive film having a region extending in one direction across multiple pixels and arranged in a different layer from the gate electrode of the transistor, A first common electrode, a second common electrode, and a third common electrode, each having a region positioned above the first conductive film, A second conductive film having a region in contact with the upper surface of the first common electrode and having a grid-like shape in the region overlapping with the first common electrode, A third conductive film having a region in contact with the upper surface of the second common electrode and having a grid-like shape in the region overlapping with the second common electrode, A fourth conductive film having a region in contact with the upper surface of the third common electrode and having a grid-like shape in the region overlapping with the third common electrode, In a plan view, the second common electrode is positioned adjacent to the first common electrode and the third common electrode, and has a region positioned between the first common electrode and the third common electrode. The first common electrode and the third common electrode are always electrically connected, at least through the first conductive film. The first common electrode and the third common electrode function as one of the electrodes of the detection element. The second common electrode functions as the other electrode of the detection element. LCD display device.

2. A liquid crystal display device having a detection element, A first conductive film having a region extending in one direction across multiple pixels and arranged in a different layer from the gate electrode of the transistor, A first common electrode, a second common electrode, and a third common electrode, each having a region positioned above the first conductive film, A second conductive film that is always in electrical contact with the first common electrode and has a grid-like shape in the region overlapping with the first common electrode, A third conductive film that is always in electrical contact with the second common electrode and has a grid-like shape in the region overlapping with the second common electrode, The present invention comprises a fourth conductive film that is always in electrical contact with the third common electrode and has a grid-like shape in the region overlapping with the third common electrode, In a plan view, the second common electrode is positioned adjacent to the first common electrode and the third common electrode, and has a region positioned between the first common electrode and the third common electrode. The first common electrode and the third common electrode are always electrically connected, at least through the first conductive film. The first common electrode and the third common electrode function as one of the electrodes of the detection element. The second common electrode functions as the other electrode of the detection element. LCD display device.

3. In Claim 1 or Claim 2, Each of the second conductive film, the third conductive film, and the fourth conductive film contains at least one of the following: molybdenum, titanium, chromium, tantalum, tungsten, aluminum, copper, silver, neodymium, or scandium. LCD display device.

4. In any one of Claims 1 to 3, The first conductive film comprises at least one of aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten. LCD display device.

5. In any one of Claims 1 to 4, It functions as a mutually capacitive touch sensor. LCD display device.

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