Semiconductor device

Abstract

To provide a capacitive element of which the capacity per occupied area is large, a semiconductor device comprising the capacitive element, a semiconductor device of a high integration degree, a high-definition display device and a display device having a stable display quality.SOLUTION: A semiconductor device (display device) comprises: a first conductive film 704a and a second conductive film 704b on an insulation surface of a substrate 700; first insulation films 712a and 712b on the first conductive film and the second conductive film on the insulation surface; a semiconductor film 706 overlapping the first conductive film via the first insulation film; a third conductive film 716b in contact with the semiconductor film; a fourth conductive film 716a which is in contact with the semiconductor film and overlaps the second conductive film via the first insulation film; second insulation films 718a-718c being on the semiconductor film and on the third conductive film and the fourth conductive film and including a thick region and a thin region; a fifth conductive film 714a overlapping the semiconductor film via the second insulation film; and a sixth conductive film 714b overlapping the fourth conductive film in the thin region of the second insulation film.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an article, a method, or a manufacturing method. , manufacture, or composition of matter. The present invention relates to, for example, a semiconductor device, a display device, a liquid crystal display device, an electroluminescence (EL: Electroluminescence) display devices, light-emitting devices, lighting devices, Alternatively, the present invention relates to a semiconductor film, a semiconductor device, a display device, a light-emitting device, a lighting device, The present invention relates to a method for manufacturing a light emitting device, a power storage device, a memory device, and a processor. The present invention relates to a display device, a light-emitting device, a lighting device, a power storage device, a storage device, and a method for driving a processor. One embodiment of the present invention is a semiconductor device, a display device, a light-emitting device, a memory device, or the like, which includes a transistor. Another aspect of the present invention relates to a device, a processor, or a driving method thereof. The semiconductor device, the display device, the light-emitting device, the storage device, or the processor This relates to electronic devices, etc.

[0002] In this specification, a semiconductor device is a device that can function by utilizing semiconductor characteristics. Display devices, light-emitting devices, electro-optical devices, semiconductor circuits, and electronic devices are all semiconductor devices. The semiconductor device may include a conductor device. [Background technology]

[0003] A technology for constructing transistors using a semiconductor film formed on a substrate with an insulating surface is The transistor is widely used in semiconductor devices such as integrated circuits and display devices. It has been done.

[0004] The semiconductor film used in the transistor is an amorphous silicon film, a polycrystalline silicon film, or an oxide semiconductor film. For example, the transistors that make up large display devices The sintered material is an amorphous silicon film or an oxide semiconductor, for which deposition technology for large-area substrates has been established. On the other hand, a highly functional display device having a driving circuit integrally formed therewith is constructed. The transistor is made of polycrystalline silicon, which allows the fabrication of transistors with high field effect mobility. A silicon film or an oxide semiconductor film is preferably used.

[0005] In recent years, the resolution of portable information terminals has increased, and the area per pixel has decreased. As the area shrinks, the proportion of wiring, transistors, and capacitance elements in a pixel increases. In order to reduce the area of ​​wiring, it is effective to use low-resistance copper wiring, for example. In order to reduce the area of ​​a transistor, for example, It is effective to use a polycrystalline silicon film or an oxide semiconductor film.

[0006] Patent Document 1 describes a transistor using an oxide semiconductor film and a capacitor using an oxide semiconductor film. A display device having the element is disclosed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2011 / 148537 Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide a capacitor element having a large capacitance per occupied area. Another object of the present invention is to provide a semiconductor device having a capacitor. It is an object of the present invention to provide a semiconductor device. This is one of the challenges.

[0009] Another object of the present invention is to provide a display device with high resolution. An object of the present invention is to provide a display device having

[0010] The description of these problems does not preclude the existence of other problems. It is not necessary for the embodiment to solve all of these problems. The above will become apparent from the description in the specification, drawings, claims, etc. It is possible to extract other issues from the descriptions in the patent, claims, etc. [Means for solving the problem]

[0011] One aspect of the present invention is described below.

[0012] (1) A first conductive film and a second conductive film on an insulating surface, and a second conductive film on the insulating surface, and a first insulating film on the second conductive film, and a semiconductor layer overlapping the first conductive film through the first insulating film. a third conductive film in contact with the semiconductor film; and a second insulating film in contact with the semiconductor film. a fourth conductive film overlapping the first conductive film, and a semiconductor film, a third conductive film, and a fourth conductive film A second insulating film having a thick region and a thin region, and a semiconductor film a fifth conductive film overlapping the fourth conductive film in a thin region of the second insulating film; and a sixth conductive film overlapping the fourth conductive film in a thin region of the second insulating film. The semiconductor device has the following features.

[0013] (2) a first conductive film and a second conductive film on an insulating surface, and a first insulating film on the second conductive film and having a thick region and a thin region; a semiconductor film overlapping the first conductive film with a third conductive film in contact with the semiconductor film; a fourth conductive film that is in contact with the semiconductor film and overlaps with the second conductive film in a thin region of the first insulating film; A second insulating film on the third conductive film and the fourth conductive film, and a semiconductor film through the second insulating film a fifth conductive film overlapping the first conductive film, a sixth conductive film overlapping the fourth conductive film via the second insulating film; The semiconductor device has the following features.

[0014] (3) a first conductive film and a second conductive film on an insulating surface, and a first insulating film on the second conductive film and having a thick region and a thin region; a semiconductor film overlapping the first conductive film with a third conductive film in contact with the semiconductor film; a fourth conductive film that is in contact with the semiconductor film and overlaps with the second conductive film in a thin region of the first insulating film; A second insulating film is disposed on the third conductive film and the fourth conductive film, the second insulating film having a thick region and a thin region. a fifth conductive film overlapping the semiconductor film via the insulating film and the second insulating film; and a sixth conductive film overlapping the fourth conductive film in the region.

[0015] (4) The semiconductor device according to any one of (1) to (3), wherein the semiconductor film is an oxide semiconductor film. It is located.

[0016] (5) The semiconductor according to any one of (1) to (3), wherein the semiconductor film is a polycrystalline silicon film. It is a device.

[0017] (6) a third insulating film on the second insulating film, the fifth conductive film and the sixth conductive film; A display element that is on the insulating film and is electrically connected to the fourth conductive film. 5) A semiconductor device according to any one of the above. Effect of the Invention

[0018] It is possible to provide a capacitive element having a large capacitance per occupied area. Alternatively, a semiconductor device having a high degree of integration can be provided. Alternatively, a novel semiconductor device can be provided. The embodiment is not limited to these effects. For example, one embodiment of the present invention may Depending on the circumstances, it may have other effects than those mentioned above. For example, one embodiment of the present invention may have these effects in some cases or depending on the situation. In some cases, it may not be available.

[0019] Alternatively, a high-definition display device can be provided. Alternatively, a display device having stable display quality can be provided. A display device can be provided. [Brief description of the drawings]

[0020] [Figure 1] 1A and 1B are a cross-sectional view and a circuit diagram illustrating an example of a capacitor of one embodiment of the present invention. [Diagram 2] 1A to 1C are a circuit diagram, a top view, and a cross-sectional view illustrating an example of a display device according to one embodiment of the present invention. [Diagram 3] FIG. 1 is a cross-sectional view illustrating an example of a display device according to one embodiment of the present invention. [Figure 4] FIG. 1 is a cross-sectional view illustrating an example of a display device according to one embodiment of the present invention. [Diagram 5] 1A and 1B are a circuit diagram and a cross-sectional view illustrating an example of a display device according to one embodiment of the present invention. [Figure 6] 1A to 1C are a circuit diagram, a top view, and a cross-sectional view illustrating an example of a display device according to one embodiment of the present invention. [Figure 7] 1A and 1B are a timing chart and a circuit diagram illustrating threshold voltage correction in a pixel of a display device according to one embodiment of the present invention. [Figure 8] 1 is a circuit diagram illustrating threshold voltage correction in a pixel of a display device according to one embodiment of the present invention. [Figure 9] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 10] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 11] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 12] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 13] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 14] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 15] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 16] 1A and 1B are a top view and a cross-sectional view illustrating an example of a method for manufacturing a display device according to one embodiment of the present invention. [Figure 17] 13A and 13B are graphs showing threshold voltage correction capabilities of a display device according to one embodiment of the present invention. [Figure 18] 1A and 1B are diagrams illustrating a display module according to one embodiment of the present invention. [Figure 19] 1A to 1C illustrate examples of electronic devices and lighting devices according to one embodiment of the present invention. [Figure 20] 1A to 1C illustrate examples of electronic devices according to one embodiment of the present invention. [Figure 21] 1 is a photograph of a display device according to one embodiment of the present invention. [Figure 22] FIG. 1 is a circuit diagram of a scan line driver circuit according to one embodiment of the present invention. [Figure 23] FIG. 2 is a diagram showing a connection relationship of a scanning line driver circuit. [Figure 24]FIG. 1 is a circuit diagram of a shift register according to one embodiment of the present invention. [Diagram 25] FIG. 1 is a circuit diagram of a shift register according to one embodiment of the present invention. [Figure 26] FIG. 1 is a circuit diagram of a shift register according to one embodiment of the present invention. [Figure 27] FIG. 1 is a circuit diagram of a shift register according to one embodiment of the present invention. [Figure 28] FIG. 1 is a circuit diagram of an inverter according to one embodiment of the present invention. [Figure 29] 1 is a timing chart of a scan line driver circuit according to one embodiment of the present invention. [Diagram 30] 13A and 13B are diagrams showing output waveforms of a scan line driver circuit according to one embodiment of the present invention. [Diagram 31] FIG. 2 is a diagram showing color coordinates of each of RGB colors of a display device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention will be described in detail with reference to the drawings. The present invention is not limited to the above, and various modifications in form and detail can be easily made by those skilled in the art. It is understood that the present invention should not be construed as being limited to the description of the following embodiments. In explaining the configuration of the invention using the drawings, the same elements are represented by different reference numerals. The hatch pattern is used in common among drawings. In some cases, no particular symbol is attached.

[0022] The contents of one embodiment may be applied or combined with the contents of another embodiment. Alternatively, a replacement or the like can be performed.

[0023] In the figures, the size, layer thickness, or area may be exaggerated for clarity. Therefore, the scale is not necessarily limited to that.

[0024] Also, a voltage is a voltage between a certain potential and a reference potential (such as ground potential (GND) or source potential). Therefore, it is possible to say "voltage" as "potential". .

[0025] In this specification, even when the expression "electrically connect" is used, it does not mean that the actual circuit is In some cases, there may be no physical connection and only wiring extending therethrough.

[0026] The ordinal numbers such as 1st and 2nd are used for convenience and do not indicate the order of steps or stacking. Therefore, for example, "the first" should not be changed to "the second" or "the third" In addition, the ordinal numbers described in this specification and the like can be replaced with the following words: The ordinal numbers used to identify an aspect of the present invention may not be consistent.

[0027] In this specification, the shape of an object may be expressed, for example, as a "diameter," "particle size," "size," When specifying the "width" etc., it is the length of one side of the smallest cube that the object can fit into, or the length of the object itself. The equivalent diameter of a circle in a cross section of an object may be read as the equivalent diameter of a circle in a cross section of an object. The diameter of a circle whose area is equal to the cross section of the body.

[0028] Even if a material is described as a "semiconductor," if its electrical conductivity is sufficiently low, it may be considered an "insulator." In addition, the boundary between "semiconductor" and "insulator" is unclear, and Therefore, the term "semiconductor" as used herein may not be distinguishable from "insulator." Similarly, the term "insulator" used in this specification may be interpreted as "semiconductor." " This can sometimes be rephrased as ".

[0029] In addition, even if a material is written as a "semiconductor," if the material has a sufficiently high electrical conductivity, it should be written as a "conductor." In addition, the boundary between "semiconductor" and "conductor" is unclear, and Therefore, the term "semiconductor" as used herein may not be distinguished from "conductor." Similarly, the term "conductor" used in this specification may be used interchangeably with "semiconductor." " This can sometimes be rephrased as ".

[0030] The impurities in the semiconductor film refer to, for example, other than the main components constituting the semiconductor film. For example, Elements with a concentration of less than 0.1 atomic% are impurities. For example, carrier traps may be formed in the semiconductor film, and carrier mobility may decrease. In some cases, the crystallinity of the semiconductor film may be decreased. In this case, impurities that change the properties of the semiconductor film include, for example, Group 1 elements, Group 2 elements, Group 14 elements, Group 15 elements, transition metals other than the main components, etc., especially hydrogen ( (Also found in water), lithium, sodium, silicon, boron, phosphorus, carbon, nitrogen, etc. In the case of an oxide semiconductor, oxygen vacancies may be formed due to the inclusion of impurities. When the semiconductor film is a silicon film, impurities that change the properties of the semiconductor film include, for example, Examples include oxygen, Group 1 elements excluding hydrogen, Group 2 elements, Group 13 elements, and Group 15 elements. .

[0031] In this specification, the term "excess oxygen" refers to oxygen contained in excess of the stoichiometric composition. Alternatively, the excess oxygen refers to oxygen that is released, for example, by heating. For example, oxygen can move inside a film or layer. The movement of excess oxygen causes the atoms of the film or layer to move. When oxygen moves between layers, it moves in a domino effect, replacing the oxygen that makes up the membrane or layer. In addition, the insulating film containing excess oxygen has a function of releasing oxygen by, for example, heat treatment. It is an insulating film having a function.

[0032] In this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. Therefore, it includes the case where the angle is between -5° and 5°. "Perpendicular" means that two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, this also includes cases where the angle is between 85° and 95°.

[0033] In the embodiment, the conductive film is made of, for example, aluminum, titanium, chromium, cobalt, etc. Nickel, Copper, Yttrium, Zirconium, Molybdenum, Ruthenium, Silver, Tanta A conductive film containing titanium or tungsten may be used in a single layer or a multilayer structure. Examples of conductive films having transparency include an In-Zn-W oxide film, an In-Sn oxide film, Oxide films such as In-Zn oxide film, indium oxide film, zinc oxide film, and tin oxide film The oxide film described above can be used even if small amounts of Al, Ga, Sb, F, etc. are added. Also, a thin metal film that transmits light (preferably, 5 nm to 30 nm) For example, a Ag film, an Mg film, or an Ag-Mg alloy film having a thickness of 5 nm can be used. A gold film may be used. Alternatively, a film that efficiently reflects visible light may be, for example, a lithium , aluminum, titanium, magnesium, lanthanum, silver, silicon or nickel A membrane may be used.

[0034] Examples of the insulating film include aluminum oxide, magnesium oxide, silicon oxide, Silicon oxynitride, silicon nitride oxide, silicon nitride, gallium oxide, germanium oxide , yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide Alternatively, an insulating film containing tantalum oxide may be used as a single layer or a multilayer. Resin films such as imide resin, acrylic resin, epoxy resin, and silicone resin may also be used. do not have.

[0035] <About the Capacitive Element> A capacitor according to one embodiment of the present invention will be described below with reference to FIG.

[0036] 1A, 1B, and 1C show examples of cross-sectional views of a capacitor element.

[0037] The capacitor element shown in FIG. 1A includes a conductive film 104 on a substrate 100 and an insulating film on the conductive film 104. 112, a conductive film 116 overlapping the conductive film 104 via the insulating film 112, and The insulating film 118 has a thick region and a thin region, and the insulating film 118 has a thin region. The conductive film 114 overlaps the insulating film 112 and the conductive film 116. The insulating film 118 is electrically connected to the conductive film 104 through an opening in the insulating film 118 .

[0038] The capacitor element shown in FIG. 1B includes a conductive film 104 on a substrate 100 and a thick region on the conductive film 104. The insulating film 112 has a thin region and a thin region, and the conductive film 10 is formed through the thin region of the insulating film 112. 4, an insulating film 118 on the conductive film 116, and a conductive film 116 The conductive film 114 overlaps the insulating film 112 and the conductive film 116. The insulating film 118 is electrically connected to the conductive film 104 through an opening in the insulating film 118 .

[0039] The capacitor element shown in FIG. 1C includes a conductive film 104 on a substrate 100 and a thick region on the conductive film 104. The insulating film 112 has a thin region and a thin region, and the conductive film 10 is formed through the thin region of the insulating film 112. A conductive film 116 overlapping the insulating film 14 and having thick and thin regions on the conductive film 116. 18 and a conductive film 114 overlapping the conductive film 116 via a thin region of the insulating film 118. The conductive film 114 is exposed through the openings in the insulating film 112 and the insulating film 118. 104 and electrically connected thereto.

[0040] For example, a transistor or a capacitor can be manufactured using various substrates. The type of substrate is not limited to a specific one. An example of the substrate is a semiconductor substrate (e.g. (e.g. single crystal substrate or silicon substrate), SOI substrate, glass substrate, quartz substrate, plastic substrate, metal substrate, stainless steel substrate, substrate with stainless steel foil , tungsten substrate, substrate with tungsten foil, flexible substrate, laminated foil Examples of the substrate include a glass substrate, a paper substrate containing a fibrous material, and a base film. For glass, barium borosilicate glass, aluminoborosilicate glass, or soda lime glass are used. Examples of flexible substrates include polyethylene terephthalate (PET), Representative examples include polyethylene naphthalate (PEN) and polyethersulfone (PES). Plastic, or synthetic resin with flexibility such as acrylic. Examples of the film include polypropylene, polyester, polyvinyl fluoride, or poly Examples of the base film include polyester, polyamide, and poly Imide, inorganic deposition film, or paper. In particular, semiconductor substrates or SOI substrates By manufacturing transistors using a plate or the like, the characteristics, size, or shape of the transistors can be It is possible to manufacture transistors with small variations, high current capability, and small size. When a circuit is constructed using such transistors, the power consumption of the circuit can be reduced or It is possible to achieve high integration of the circuits.

[0041] Note that transistors and capacitors are fabricated using one substrate, and then the transistors and capacitors are fabricated on another substrate. The transistors and capacitors may be transposed and disposed on a different substrate. An example of the substrate on which the transistors and capacitors are transferred is In addition to the substrates that can be used to make the 3D effect, paper substrates, cellophane substrates, stone substrates, wood substrates, cloth substrates, etc. Substrates (natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (including acetate, cupra, rayon, recycled polyester, etc.), Leather substrates, rubber substrates, etc. By using these substrates, Fabrication of transistors, fabrication of low-power transistors, fabrication of durable devices, heat-resistant devices It is possible to provide the device with improved durability, weight reduction, or thinness.

[0042] In addition, all of the circuits required to realize a given function can be fabricated on the same substrate. This allows for cost reduction by reducing the number of components, or the number of connection points with circuit components. The reduction in number of components can improve reliability.

[0043] It is not necessary to fabricate all of the circuits required to realize a given function on the same substrate. In other words, part of the circuitry required to realize a given function is fabricated on a certain substrate, and Other parts of the circuitry required to achieve a certain function may be fabricated on other substrates. For example, a part of the circuitry required to realize a given function is fabricated on a glass substrate, and a given Another part of the circuitry required to realize the function is fabricated on the semiconductor substrate (or SOI substrate). Then, another part of the circuitry required to realize a given function can be created. The semiconductor substrate (also called IC chip) is then processed using COG (Chip On Glass) ) to connect to the glass substrate and place the IC chip on the glass substrate. Or, the IC chip is attached to the TAB (Tape Automated Bonding g), COF (Chip On Film), SMT (Surface Mount T It is possible to connect to the glass substrate using a printed circuit board or other similar device. In this way, part of the circuit is fabricated on the same substrate as the pixel section, Cost reduction by reducing the number of parts, or reliability improvement by reducing the number of connections to circuit components In particular, it is possible to improve the driving voltage of circuits that have a high driving frequency or circuits that have a high driving frequency. In many cases, circuits that consume a large amount of power. The pixel section is fabricated on a separate substrate to form an IC chip. This makes it possible to prevent an increase in power consumption.

[0044] The capacitance element shown in FIG. 1(A), FIG. 1(B), and FIG. 1(C) includes a conductive film 104, an insulating film 11, and a 2 and a conductive film 116; and a capacitance element C1 having the conductive film 116, an insulating film 118 and a conductive and a capacitance element C2 having a film 114. Therefore, in FIG. The capacitance element shown in FIG. 1C is a circuit in which a capacitance element C1 and a capacitance element C2 are connected in parallel. (See FIG. 1(D)). That is, FIG. 1(A), FIG. 1(B) and FIG. The capacitance of the capacitive element shown in (C) is the sum of the capacitance of the capacitive element C1 and the capacitance of the capacitive element C2.

[0045] In the capacitive element shown in FIG. 1A, the capacitive element C2 uses a thin region of the insulating film 118. Therefore, the capacitance per occupied area can be increased. In the device, the capacitance element C1 utilizes a thin region of the insulating film 112, so In the capacitor shown in FIG. 1C, the capacitor C1 is an insulating The thin region of the insulating film 112 is used for the capacitance element C1, and the thin region of the insulating film 118 is used for the capacitance element C2. , the capacity per occupied area can be increased.

[0046] In this way, the capacitance elements shown in FIGS. 1(A), 1(B) and 1(C) have a capacitance per occupied area of It is a capacitive element with a large capacitance.

[0047] By using the capacitor elements shown in FIG. 1(A), FIG. 1(B), and FIG. 1(C) in a semiconductor device, This allows for an increase in the degree of integration of the semiconductor device. A semiconductor device having an element can be provided.

[0048] The capacitance elements shown in FIG. 1(A), FIG. 1(B) and FIG. 1(C) are, for example, transistors and For example, the conductive film 104 may be formed in the same process. The conductive film can be used as a gate electrode of a transistor. The insulating film formed through the same process as the film 112 is used as a gate insulating film of a transistor. In addition, for example, a conductive film formed through the same process as the conductive film 116 can be It can be used as a source electrode or a drain electrode of a transistor. An insulating film formed through the same process as the insulating film 118 is used as a protective insulating film for the transistor. In addition, for example, a conductive film formed through the same process as the conductive film 114 can be The conductive film 114 may be used as a second gate electrode of the transistor. When the conductive film formed through the process is used as the second gate electrode of a transistor, The insulating film formed through the same process as the insulating film 118 is used as the second gate insulating film of the transistor. In addition, the insulating film constituting the capacitance element can be made to function in a thick region and a thin region. In the photolithography process, a multi-tone mask (also called a gray-tone mask) is used. By using a multi-tone mask, the number of photomasks can be reduced. This may enable the company to increase productivity.

[0049] In this way, by combining transistors and capacitors, any semiconductor device can be manufactured. Examples of the semiconductor device include a display device, a memory device, and a processor. The capacitance elements shown in FIG. 1(A), FIG. 1(B) and FIG. 1(C) have a capacitance per occupied area of Since the capacitance of the capacitor is large, it is suitable for use in display devices with high display quality and memory devices with excellent retention characteristics. It is possible to realize a high-resolution display device, a processor with low power consumption, etc. Thus, a highly integrated memory device and processor can be realized.

[0050] At least the conductive film constituting the capacitance element shown in FIG. 1(A), FIG. 1(B) and FIG. 1(C) In that case, for example, the capacitor element may be used In some cases, the aperture ratio of a display device using the capacitive element can be increased. It may be possible to reduce the power consumption of the device.

[0051] However, one aspect of the embodiment of the present invention is not limited to this. Depending on the circumstances, the insulating film of the capacitive element does not need to be thin.

[0052] <Display device> A display device according to one embodiment of the present invention will be described below with reference to FIGS.

[0053] Display elements used in display devices include liquid crystal elements (also called liquid crystal display elements), light-emitting elements, etc. The light-emitting element can be a light-emitting display element. Therefore, the category includes elements whose brightness can be controlled, specifically inorganic EL, organic EL, etc. Also, electronic ink, electrophoretic elements, etc., which change contrast due to electrical effects Display media that display images, grating light valves (GLVs), plasma display panels (PDP), MEMS (Micro Electro Mechanical Systems), Digital Micro Chromatic mirror device (DMD), DMS (digital micro shutter), IMOD (Interference Modulation) elements, electrowetting elements, pressure Electroceramic displays, carbon nanotubes, etc. can also be used as display elements. In the following, a display device using an EL element (EL display device) will be described as an example of the display device. ) and a display device using a liquid crystal element (liquid crystal display device) will be described.

[0054] The display device described below is a panel in which a display element is sealed, and a control circuit is attached to the panel. This includes modules in which ICs including controllers are mounted.

[0055] The display device described below refers to an image display device or a light source (including a lighting device). Also, connectors, such as FPC, modules with TCP attached, and TCP with printers A module or display element with a printed wiring board has an IC (integrated circuit) mounted on it by the COG method. The display device also includes all modules mounted on the display device.

[0056] 2A and 2B are diagrams illustrating an example of an EL display device according to one embodiment of the present invention. FIG. 2(B) is a top view showing the entire EL display device. 2(C) is a cross section of MN corresponding to a part of the dashed line MN in FIG. 2(B).

[0057] FIG. 2A is an example of a circuit diagram of a pixel used in an EL display device.

[0058] In this specification, the terms "active elements" and "passive elements" are used interchangeably. For all terminals of devices (capacitive elements, resistive elements, etc.), the connection destination is not specified. However, a person skilled in the art may be able to configure one aspect of the invention. Even if the destination is not specified, one aspect of the invention is clear. When the contents are described in this specification, etc., one aspect of the invention that does not specify a connection destination is the same as the embodiment of the present specification. In particular, if the terminal is connected to multiple When multiple locations are anticipated, it is not necessary to limit the connection destination of the terminal to a specific location. Therefore, active elements (transistors, diodes, etc.) and passive elements (capacitive elements, resistive elements) By specifying the connection destinations of only some of the terminals on It may be possible to configure a clear embodiment.

[0059] In this specification and the like, if at least the connection destination of a certain circuit is specified, it is understood by those skilled in the art that If you are a person who has experience in the field of electronics, you may be able to identify the invention. In some cases, a person skilled in the art can identify an invention by at least specifying the function. In other words, if the function is specified, one aspect of the invention is clear. It may be possible to determine that one aspect of the invention is described in the present specification. Therefore, even if the function of a circuit is not specified, if the connection destination is specified, it can be considered as an embodiment of the invention. and can constitute one embodiment of the invention. For a certain circuit, even if the connection destination is not specified, if the function is specified, it can be considered as one aspect of the invention. What is disclosed can constitute an embodiment of the invention.

[0060] The EL display device shown in FIG. 2A includes a switch element 743, a transistor 741, and a capacitor. It has an element 742 and a light-emitting element 719.

[0061] Note that FIG. 2A and the like are merely examples of circuit configurations, and therefore, a transistor may be added. Conversely, at each node in FIG. 2(A), transistors, switches, and receivers can be used. It is also possible not to add any moving elements.

[0062] The gate of the transistor 741 is connected to one end of the switch element 743 and one end of the capacitance element 742. The source of the transistor 741 is electrically connected to the other electrode of the capacitor 742. and is electrically connected to one electrode of the light-emitting element 719. The drain of the switch element 741 is supplied with a power supply potential VDD. The other end of the switch element 743 is connected to the signal line 7 The other electrode of the light-emitting element 719 is electrically connected to the light-emitting element 44. A constant potential is applied to the other electrode of the light-emitting element 719. The constant potential is the ground potential GND or a potential lower than that.

[0063] It is preferable to use a transistor as the switch element 743. This allows the pixel area to be reduced, resulting in an EL display device with high resolution. The switch element 743 is a transistor manufactured through the same process as the transistor 741. The use of a photoresist can increase the productivity of EL displays.

[0064] 2B is a top view of the EL display device. The EL display device is made up of a substrate 700 and a substrate 75. 0, a sealant 734, a driving circuit 735, a driving circuit 736, a pixel 737, and an FPC The sealing material 734 is provided on the pixel 737, the driving circuit 735, and the driving circuit 736. 36 is disposed between the substrate 700 and the substrate 750. Alternatively, the driving circuit 736 may be disposed outside the sealing material 734 .

[0065] FIG. 2C is a cross-sectional view of the EL display device corresponding to a part of the dashed line MN in FIG. 2B. do.

[0066] In FIG. 2C, a conductive film 704 a and a conductive film An insulating film 712a on 704a, an insulating film 712b on the insulating film 712a, and an insulating film 712b A semiconductor film 706 that is located above and overlaps with the conductive film 704a and a conductive film 71 that is in contact with the semiconductor film 706 6a and the conductive film 716b, and the semiconductor film 706, the conductive film 716a, and the conductive film 716 b, an insulating film 718a on the insulating film 718a, and an insulating film 718b on the insulating film 718b. an insulating film 718c, and a conductive film 714a that is on the insulating film 718c and overlaps with the semiconductor film 706; Note that the structure of the transistor 741 is just an example, and the structure shown in FIG. The structure may be different from that of the existing structure.

[0067] Therefore, in the transistor 741 shown in FIG. The insulating film 712a and the insulating film 712b function as a gate insulating film, and the conductive film 712b function as a conductive electrode. The conductive film 716a functions as a source electrode, and the conductive film 716b functions as a drain electrode. The insulating films 718a, 718b, and 718c function as gate insulating films. The conductive film 714a functions as a gate electrode. The electrical characteristics may vary. It is preferable that at least one of the conductive film 716b and the conductive film 714a has a light-shielding property.

[0068] The interface between the insulating film 718a and the insulating film 718b is indicated by a dashed line. For example, the insulating films 718a and 718b may not be clearly defined. Therefore, when the same type of insulating film is used, it may be difficult to distinguish between the two depending on the observation method.

[0069] In FIG. 2C, a conductive film 704b over a substrate and a conductive film 704b over the conductive film 704b are used as a capacitor 742. The insulating film 712a is an insulating film 712b on the insulating film 712a. The insulating film 712b is a conductive film. A conductive film 716a overlapping the conductive film 704b, an insulating film 718a on the conductive film 716a, and an insulating film An insulating film 718b on the insulating film 718a, an insulating film 718c on the insulating film 718b, and an insulating film 718c and a conductive film 714b that is located above and overlaps the conductive film 716a. In the region where the film 714b overlaps, the insulating film 718a and the insulating film 718b are partially removed. The structure shown is as follows.

[0070] In the capacitor 742, the conductive film 704b and the conductive film 714b function as one electrode. The conductive film 716a functions as the other electrode.

[0071] Therefore, the capacitor 742 can be formed using a film common to the transistor 741. In addition, it is preferable that the conductive films 704a and 704b be made of the same type of conductive film. In that case, the conductive film 704a and the conductive film 704b can be formed through the same process. In addition, the conductive films 714a and 714b are preferably made of the same type of conductive film. In this case, the conductive film 714a and the conductive film 714b can be formed in the same process. .

[0072] The capacitor 742 shown in FIG. 2C has a structure similar to that of the capacitor shown in FIG. Similar to the capacitor shown in FIG. 1A, this capacitor has a large capacitance per occupied area. Therefore, the EL display device shown in FIG. 2(C) has high display quality. The capacitor element 742 is formed by thinning the overlapping area of ​​the conductive film 716a and the conductive film 714b. 7, the insulating film 718a and the insulating film 718b are partially removed. The capacitive element according to the embodiment is not limited to this. In order to thin the overlapping region of the conductive film 714b, a part of the insulating film 718c is removed. It's okay to do so.

[0073] Note that the structure of the capacitor 742 is just an example and is different from the structure shown in FIG. For example, in FIG. 3A, the capacitor 742 may be the capacitor shown in FIG. Specifically, the EL display device has a structure similar to that of the capacitive element shown in FIG. The electrode 742 is a part of the insulating film 712b in the region where the conductive film 704b and the conductive film 716a overlap each other. Note that the capacitor 742 shown in FIG. In order to thin the region where the insulating film 712b and the conductive film 716a overlap, a part of the insulating film 712b is removed. However, the capacitor according to one embodiment of the present invention is not limited to this structure. For example, in order to thin the overlapping region of the conductive film 704b and the conductive film 716a, the insulating film 712 A structure in which a is partially removed may also be used.

[0074] The structure of the capacitor 742 is just an example, and the structures shown in FIG. 2C and FIG. 3A may be different. For example, in FIG. 3B, the capacitor 742 is This is an EL display device having a structure similar to that of the capacitive element shown in FIG. The capacitor 742 shown in FIG. 7B is insulated in a region where the conductive film 704b and the conductive film 716a overlap each other. A part of the insulating film 712b is removed, and in the area where the conductive film 716a and the conductive film 714b overlap, The insulating film 718a and the insulating film 718b are partially removed. In the capacitor 742 shown in FIG. 1, the conductive film 716a and the conductive film 714b are thinned in an overlapping region. Therefore, the insulating film 718a and the insulating film 718b are partially removed. The capacitor according to the present embodiment is not limited to this. In order to thin the overlapping region of the conductive film 714b, a part of the insulating film 718c is removed. The capacitor 742 shown in FIG. In order to thin the area where the insulating film 712b overlaps with the conductive film 716a, a part of the insulating film 712b is removed. However, the capacitor according to one embodiment of the present invention is not limited thereto. For example, In order to thin the overlapping region of the conductive film 704b and the conductive film 716a, It is also possible to have a structure in which a portion is removed.

[0075] In FIG. 2C, FIG. 3A, and FIG. 3B, a transistor 742 is connected to a part of the capacitor element 742. FIG. 4 shows a structure having a conductive film 716a functioning as a source electrode of the capacitor 41. A structure in which a semiconductor film 707 is included in a part of an element 742 is shown.

[0076] In FIG. 4A, a conductive film 704b over a substrate and a conductive film 704b over the conductive film 704b are used as a capacitor 742. The insulating film 712a is an insulating film 712b on the insulating film 712a. The insulating film 712b is a conductive film. A semiconductor film 707 overlapping the conductive film 704b, an insulating film 718a on the semiconductor film 707, and an insulating film An insulating film 718b on the insulating film 718a, an insulating film 718c on the insulating film 718b, and an insulating film 718c and a conductive film 714b that is located above and overlaps the semiconductor film 707. In the region where the film 714b overlaps, the insulating film 718a and the insulating film 718b are partially removed. The structure shown is as follows.

[0077] The semiconductor film 707 is preferably a semiconductor film that functions as an electrode of the capacitor 742. Therefore, it is preferable that the semiconductor film 707 is a degenerate semiconductor. Even if the carrier density of 07 is low, the conductive film 704b and / or the conductive film 714b Carriers can be induced in the semiconductor film 707 by the electric field.

[0078] It is preferable that the semiconductor film 706 and the semiconductor film 707 are made of the same type of semiconductor film. In this case, the semiconductor film 706 and the semiconductor film 707 can be formed through the same process.

[0079] By the way, the semiconductor film 706 functions as a semiconductor film of the transistor 741. It is preferable to use a semiconductor film with a low rear density. Since the semiconductor film functions as an electrode, it is preferable to use a semiconductor film having a high carrier density. In the case where the semiconductor film 706 and the semiconductor film 707 are formed through the same process, Therefore, it is preferable to fabricate each of them so that the carrier density is appropriate.

[0080] For example, the semiconductor film 706 and the semiconductor film 707 are formed of a semiconductor film having a high carrier density. The carrier density of the semiconductor film 706 may be reduced in a later process. As a method for reducing the carrier density, for example, when the semiconductor film 706 is an n-type semiconductor, In this case, an acceptor may be implanted, and in the case where the semiconductor film 706 is a p-type semiconductor, a donor may be implanted. Alternatively, a carrier generation source in the semiconductor film 706 may be reduced. For example, In the case where the semiconductor film 706 is an oxide semiconductor film, oxygen vacancies in the oxide semiconductor film capture hydrogen. Therefore, in the case of an oxide semiconductor film, By adding oxygen to the mixture, oxygen vacancies can be reduced, or by applying heat, etc., hydrogen can be reduced. The carrier density of the semiconductor film 706 can be reduced.

[0081] Alternatively, for example, the semiconductor film 706 and the semiconductor film 707 may be made of a semiconductor having a low carrier density. Alternatively, a semiconductor film may be formed on the semiconductor film 707, and the carrier density of the semiconductor film 707 may be increased in a later process. As a method for increasing the carrier density of the semiconductor film 707, for example, a dopant is added to the semiconductor film 707. Alternatively, a carrier generation source may be formed in the semiconductor film 707. For example, In the case where the semiconductor film 707 is an oxide semiconductor film, hydrogen is captured in oxygen vacancies in the oxide semiconductor film. Therefore, in the case of an oxide semiconductor film, The carriers of the semiconductor film 707 can be formed by desorbing oxygen in a neutral environment or by supplying hydrogen. The density can be increased.

[0082] In the capacitor 742 illustrated in FIG. 4A, for example, the insulating film 718c is a semiconductor film. By using an insulating film containing impurities that become a carrier generation source in the semiconductor film 707, The carrier density may be increased. Specifically, the semiconductor film 707 is an oxide semiconductor film. In this case, by using an insulating film containing hydrogen as the insulating film 718c, the carrier The hydrogen-containing insulating film can increase the hydrogen density. Therefore, the insulating film 718c and the semiconductor film 707 are preferably used. By adopting the structure in contact with the semiconductor film 7, the capacitance of the capacitor 742 can be increased and the semiconductor film 7 Therefore, the carrier density of the GaN- ... This reduces the number of steps, and the productivity of the display device can be improved.

[0083] Note that the capacitor 742 shown in FIG. 4A is formed by overlapping the semiconductor film 707 and the conductive film 714b. In order to thin the region, a structure in which a part of the insulating film 718a and the insulating film 718b are removed is used. However, the capacitor according to one embodiment of the present invention is not limited thereto. In order to thin the overlapping area of ​​the conductive film 707 and the conductive film 714b, a part of the insulating film 718c is It is also possible to have a structure in which the is removed.

[0084] As the capacitor 742 using the semiconductor film 707, the capacitor 74 shown in FIG. 4B shows an example different from that of the capacitor 742 shown in FIG. In the region where the insulating film 707 overlaps, a part of the insulating film 712b is removed. In the capacitor 742 shown in FIG. 7B, the conductive film 704b and the semiconductor film 707 are overlapped with each other by thinning the conductive film 704b. In order to reduce the size of the insulating film 712b, a part of the insulating film 712b is removed. The capacitor element is not limited to this. For example, the conductive film 704b and the semiconductor film 70 In order to thin the overlapping region of the insulating film 712a, a part of the insulating film 712a may be removed. do not have.

[0085] In Fig. 2(C), Fig. 3(A), Fig. 3(B), Fig. 4(A) and Fig. 4(B), FPC7 32 is connected to a wiring 733a via a terminal 731. A conductive film or a semiconductor film of the same type as the conductive film or the semiconductor film constituting the transistor 741 is also acceptable.

[0086] An insulating film 720 is provided over the transistor 741 and the capacitor 742. The insulating film 720 reaches the conductive film 716a which functions as a source electrode of the transistor 741. A conductive film 781 is provided over the insulating film 720. 1 may be electrically connected to the transistor 741 through an opening in the insulating film 720.

[0087] A partition 784 having an opening reaching the conductive film 781 is provided over the conductive film 781. A light-emitting layer 782 is disposed on the wall 784 so as to be in contact with the conductive film 781 at the opening of the partition wall 784. A conductive film 783 is disposed over the light-emitting layer 782. The overlapping region of the conductive film 783 becomes the light-emitting element 719 .

[0088] So far, an example of an EL display device has been described. Next, an example of a liquid crystal display device will be described. do.

[0089] FIG. 5(A) is a circuit diagram showing an example of the configuration of a pixel of a liquid crystal display device. A transistor 751, a capacitor element 752, and an element in which liquid crystal is filled between a pair of electrodes (liquid crystal element) Child) 753.

[0090] In the transistor 751, one of the source and the drain is electrically connected to a signal line 755. The gate is electrically connected to a scan line 754 .

[0091] In the capacitor 752, one electrode is electrically connected to the other of the source and drain of the transistor 751. The other electrode is electrically connected to a wiring that supplies a common potential.

[0092] In the liquid crystal element 753, one electrode is electrically connected to the other of the source and drain of the transistor 751. The other electrode is electrically connected to a wiring that supplies a common potential. A common potential applied to a wiring to which the other electrode of the capacitor 752 is electrically connected, The common potential applied to the other electrode of the liquid crystal element 753 may be different from the common potential applied to the other electrode of the liquid crystal element 753 .

[0093] The liquid crystal display device will be described assuming that the top view is the same as that of the EL display device. A cross-sectional view of the liquid crystal display device corresponding to the dashed line MN is shown in FIG. The FPC 732 is connected to a wiring 733a via a terminal 731. A conductive film or a semiconductor film of the same type as the conductive film or the semiconductor film constituting the transistor 751 A semiconductor film may also be used.

[0094] For the transistor 751, refer to the description of the transistor 741. For 752, refer to the description of the capacitor 742. 7B, the structure of the capacitor 752 corresponding to the capacitor 742 of FIG. For example, the capacitor 752 shown in FIG. A structure corresponding to the above-mentioned capacitor 742 may be used.

[0095] Note that when an oxide semiconductor film is used as the semiconductor film of the transistor 751, the off-state current is extremely low. Therefore, the charge held in the capacitor 752 Therefore, the voltage applied to the liquid crystal element 753 can be maintained for a long period of time. Therefore, when a moving image or a still image with little movement is displayed, the transistor 751 is turned off. By setting the transistor 751 in this state, power for the operation of the transistor 751 is not required, and the power consumption is low. In addition, the area occupied by the capacitor 752 can be reduced. Therefore, it is possible to provide a liquid crystal display device with a high aperture ratio or a high-definition liquid crystal display device. do.

[0096] An insulating film 721 is provided over the transistor 751 and the capacitor 752. The insulating film 721 has an opening that reaches the transistor 751. The conductive film 791 is connected to the transistor through the opening of the insulating film 721. Electrically connect to 751.

[0097] An insulating film 792 functioning as an alignment film is provided over the conductive film 791. A liquid crystal layer 793 is disposed on the liquid crystal layer 793. An insulating film 7 94 is disposed on the insulating film 794. A spacer 795 is disposed on the insulating film 794. A conductive film 796 is disposed on the insulating film 794. 7 is placed.

[0098] By using the above-mentioned structure, it is possible to provide a display device having a capacitance element with a small occupancy area. Alternatively, a display device with high display quality can be provided. It is possible to provide a display device.

[0099] <High-definition display devices> An example of a pixel constituting a high-definition EL display device will be shown below.

[0100] FIG. 6 shows a pixel of an EL display device. The EL display device shown in FIG. , transistor 972, transistor 973, transistor 974, and transistor 975, a capacitance element 976, a light emitting element 919, a signal line SL, a power line PL1, and a power The scanning line PL2, the scanning line GL1, the scanning line GL2, and the scanning line GL3.

[0101] The potential of the pixel electrode of the light emitting element 919 is controlled according to an image signal input to the pixel. Alternatively, the luminance of the light-emitting element 919 is determined by the potential difference between the pixel electrode and the common electrode. In this case, the anode of the light emitting element 919 functions as a pixel electrode, and the cathode functions as a common electrode. It works.

[0102] FIG. 6A shows a circuit diagram of a pixel, and the connection relationship between each element and wiring will be described below.

[0103] The transistor 971 controls the electrical continuity between the signal line SL and one electrode of the capacitor 976. The other electrode of the capacitor 976 is connected to the source of the transistor 972, The transistor 973 is electrically connected to one of the power supply lines PL2 and The transistor 974 has a function of controlling the conduction state between the gate of the transistor 972 and the gate of the transistor 974. A gate electrode of the transistor 972 is connected to the capacitor 976. The transistor 975 has a function of connecting one of the source and drain of the transistor 972. The transistor 97 has a function of controlling the electrical continuity between the anode of the light-emitting element 919 and the transistor 97. 2 has a function of controlling the conduction state between the power supply line PL1 and the other electrode of the capacitance element 976. do.

[0104] The conduction state of the transistor 971 is determined by electrically connecting the gate of the transistor 971 to the The conductive state of the transistor 973 is controlled by the potential of the scanning line GL1. The gate of the transistor 973 is electrically connected to the scanning line GL1. The conductive state of the transistor 974 is determined by the scanning line GL The conductive state of the transistor 975 is controlled by the potential of the transistor 975. It is controlled by the potential of the scanning line GL3 electrically connected to the gate.

[0105] Transistor 971, transistor 972, transistor 973, transistor 974, and The transistor 975 is preferably made of an oxide semiconductor or silicon. When an oxide semiconductor is used for the transistor 971, the transistor 973, and the transistor 974, , the off-current of the transistor 971, the transistor 973, and the transistor 974 is This is particularly preferable because the size of the transistor can be reduced by the above-mentioned method. By using the transistors 971, 973, and 974 in a pixel, Compared to using transistors made of semiconductors such as silicon or germanium, This can prevent leakage of charges stored in the gate of the transistor 972.

[0106] Therefore, like a still image, the same image information is displayed on the pixel portion over several consecutive frame periods. In cases where an image signal having information is written, the driving frequency can be lowered. In other words, even if the number of times that image signals are written to the pixel section within a certain period of time is reduced, the image For example, a highly purified oxide semiconductor can be used as the transistor 9 71, the transistor 973 and the transistor 974 are used to write an image signal. The interval between recordings can be set to 10 seconds or more, 30 seconds or more, or 1 minute or more. The longer the interval at which data is written, the greater the reduction in power consumption.

[0107] In addition, the potential of the image signal can be held for a longer period of time. Even if the capacitance of the capacitance element 976 for holding the potential of the gate of the transistor 972 is reduced, It is possible to prevent the display image quality from being deteriorated. Since the size of the light-emitting element can be reduced, the aperture ratio of the pixel can be increased. This can extend the life of 919 and improve the reliability of EL display devices.

[0108] In FIG. 6A, the pixel may include a transistor, a diode, a resistor, etc., as necessary. The semiconductor device may further include other elements such as resistors, capacitors, and inductors.

[0109] In addition, in FIG. 6A, a transistor 971, a transistor 972, and a transistor The transistor 73 and the transistor 975 have a second gate (also called a back gate). Transistor 971, transistor 972, transistor 973 and transistor 97 In 5, the second gate is electrically connected to the gate. Therefore, the second gate The drain current can be increased by the electric field applied from the second By having a gate, the drain voltage required to saturate the drain current of the transistor is That is, it is easy to keep the drain current constant, so that the light emitting element 919 Therefore, it is possible to easily control the gradation of the light emitting element 919. This makes it easier to realize a display device with high display quality.

[0110] In addition, in FIG. 6A, the transistor 974 does not have a second gate. This is because By reducing the parasitic capacitance associated with the gate of the transistor 974, This is because the ability of threshold voltage correction can be improved.

[0111] In FIG. 6A, a transistor 971, a transistor 972, a transistor 973, and Transistor 975 has a second gate and transistor 974 does not have a second gate. The present embodiment is not limited to the above embodiment. The value can be appropriately changed depending on the structure of the transistor.

[0112] In FIG. 6A, all the transistors are n-channel transistors. If all the transistors in a pixel are of the same channel type, then there are transistors of different channel types in the pixel. The manufacturing process of the transistor can be simplified compared to the case where a transistor is provided. In the EL display device according to one embodiment of the present invention, all the transistors in a pixel are n-channel transistors. This is not limited to the case where:

[0113] Next, the operation of the pixel shown in FIG. 6(A) will be described with reference to FIGS.

[0114] FIG. 7A shows timing charts showing the potentials of the scanning lines GL1 to GL3 and the potential of the signal line SL. FIG. 7B is a timing chart showing the state of the initializing operation in the period T1 in FIG. In response to the above, the potentials of the scanning lines GL1 to GL3 and the transistors 971 to The potentials of the scanning lines GL1 to GL3 are at a low level. If it is low, it is represented as L, and if it is high level, it is represented as H.

[0115] In the period T1, a low-level potential is applied to the scanning line GL1, and a low-level potential is applied to the scanning line GL2. A potential of a high level is applied to the scanning line GL1, and a potential of a high level is applied to the scanning line GL2. The transistor 975 is turned on, and the transistors 971, 973 and During the period T1, the transistor 974 is turned off due to the effect of the previous light emitting operation. Transistor 972 begins in a conductive state.

[0116] In addition, a potential Vano is applied to the power supply line PL1, and a potential Vc At is applied to the power supply line PL2, and a potential V0 is applied to the signal line SL. The potential Vdata of the signal is given. The potential V0 is the threshold voltage of the transistor 972. The voltage Vth and the threshold voltage Vthe of the light emitting element 919 are added to the potential Vcat. is higher than the sum of the threshold voltage Vth of the transistor 972 and the potential Vano. It is preferable that it is low.

[0117] In the period T1, the transistor 972, the transistor 975, and the capacitance element 976 The potential in node A is initialized to a potential close to the threshold voltage Vthe of the light emitting element 919. It is possible.

[0118] FIG. 8A shows the potential Vdata of the signal line SL and the transistor 97 in FIG. The scanning lines GL1 to GL3 corresponding to the period T2 for acquiring the threshold voltage Vth of 9 shows the potential of transistor 971 to transistor 975 and the conduction states of transistors 971 to 975.

[0119] In the period T2, a high-level potential is applied to the scanning line GL1, and a low-level potential is applied to the scanning line GL2. A potential of a high level is applied to the scanning line GL1, and a potential of a low level is applied to the scanning line GL2. A potential V0 is applied to the gate of the transistor 972. Then, the charge of the capacitance element 976 is discharged, and the potential of the node A, which was at the potential Vcat, begins to rise. Finally, when the potential of node A becomes V0-Vth, the gate of transistor 972 The voltage drops to the threshold voltage Vth, and transistor 972 becomes non-conductive. In addition, a potential Vdata is applied to one electrode (referred to as a node B) of the capacitor 976. Given.

[0120] FIG. 8B shows the scanning lines GL1 to GL2 corresponding to the period T3 showing light emission in FIG. 7A. GL3 and the conduction states of transistors 971 to 975. .

[0121] In the period T3, a low level potential is applied to the scanning line GL1, and a high level potential is applied to the scanning line GL2. A potential of a high level is applied to the scanning line GL3, and a potential of a high level is applied to the scanning line GL4. The transistor 974 and the transistor 975 are turned on. In addition, when the period T2 is changed to the period T3, the transistor 973 is turned off. At this time, the potential applied to the scanning line GL1 is switched from high level to low level, and then the potential applied to the scanning line G It is preferable to switch the potential applied to the scanning line GL2 and the scanning line GL3 from a low level to a high level. This is preferable. This makes it possible to suppress fluctuations in potential.

[0122] During the period T3, the potential Vdata is applied to the gate of the transistor 972 by the above operation. Therefore, the gate voltage Vgs of the transistor 972 becomes Vdata-V0+Vth. Therefore, the gate voltage Vgs of the transistor 972 is multiplied by the threshold voltage Vth. The value can be set as:

[0123] Specifically, the current value supplied to the light emitting element 919 is I OLED Then, I OLED =0 .5β(Vgs-Vth) 2 Here, β is a parameter specific to the transistor. Specifically, β = (W / L) μ FE ·Cox. W is the transistor is the channel width of the transistor, L is the channel length of the transistor, and μ FE is a transistor where, Cox is the gate capacitance of the transistor, and Substituting the voltage Vgs = Vdata-V0+Vth, I OLED =0.5β(Vdata -V0) 2 This is expressed as:

[0124] That is, in the pixel of the EL display device shown in FIG. 6A, the threshold voltage Vt The variation in h affects the current I OLED Reduce the impact on In addition, the transistor 972 is deteriorated. Even if the threshold voltage Vth fluctuates, the current value I OLE D Therefore, it is possible to provide a display device with less display unevenness. It is possible.

[0125] Next, an example of the structure of an EL display device having a threshold voltage correction function shown in FIG. The following description will be given with reference to Figs. 6(B) and 6(C). In order to facilitate understanding, in Fig. 9C, some components such as a light-emitting element 919 are omitted.

[0126] FIG. 6B is a top view corresponding to a pixel of the EL display device shown in FIG. The size of one pixel of a display device is expressed as xμm×yμm. For example, the size of one pixel in an EL display is 38.25 μm × 12.75 μm (664 ppi equivalent).

[0127] In this way, in the pixel of a high-definition EL display device, the area occupied by the capacitor element 976 is sufficiently large. In the circuit configuration shown in FIG. 6 is preferably twice the parasitic capacitance associated with the gate of transistor 972, and more preferably It is advisable to use a volume 5 times, more preferably 10 times, the capacity.

[0128] FIG. 6C is a cross-sectional view corresponding to the dashed line F1-F2 and the dashed line F3-F4 in FIG. 6B. It is.

[0129] The pixel shown in FIG. 6C includes a conductive film 904a and a conductive film 904b on a substrate 900, and a conductive An insulating film 912a on the conductive film 904a and the conductive film 904b, and an insulating film 91 2b, a semiconductor film 906 that is on the insulating film 912b and overlaps with the conductive film 904a, and a semiconductor film 9 06, and the conductive film 916a and the conductive film 916b on the semiconductor film 906 and the conductive film 916 a and the conductive film 916b, and an insulating film 918b on the insulating film 918a. An insulating film 918c on the insulating film 918b and a semiconductor film 906 overlapping the insulating film 918c are provided. a conductive film 914a that is disposed on the insulating film 918c and overlaps with the conductive film 916b; , the insulating film 908 on the insulating film 918c, the conductive film 914a, and the conductive film 914b, The conductive film 926 includes a conductive film 926a, a conductive film 926b, and a conductive film 926c over the film 908.

[0130] The conductive film 926b is formed by stacking the insulating films 918a, 918b, and 918c. The conductive film 914a is electrically connected to the conductive film 916b through the opening of the conductive film 908. The insulating films 912a, 912b, 918a, 918b, and 9 The insulating film 918a and the conductive film 904a are electrically connected to each other through the openings in the insulating film 918c. The insulating film 918b has an opening in a part on the conductive film 916a, and the conductive film 916a and insulating film 918c are in contact with each other.

[0131] In the transistor 975, the conductive film 904a functions as a gate electrode, and the insulating film 912 a and the insulating film 912b function as a gate insulating film, and the conductive film 916a functions as a source electrode. The conductive film 916b functions as a drain electrode, and the insulating film 918a and the insulating film 918b function as a drain electrode. b and the insulating film 918c function as a gate insulating film, and the conductive film 914a functions as a gate electrode. It works like this.

[0132] In the capacitor 976, the conductive film 904b and the conductive film 914b serve as one electrode. The conductive film 916a functions as the other electrode.

[0133] Note that the transistor 975 has a structure similar to that of the transistor 741. The description of the transistor 741 can be referred to for the transistor 975. , transistor 971, transistor 972, transistor 973 and transistor 9 The description of the transistor 741 can also be referred to for the capacitor 976. The capacitor 976 has a structure similar to that of the capacitor 742. Please refer to the description of the quantum element 742.

[0134] In the pixels shown in FIG. 6B and FIG. 6C, the area occupied by the capacitor element 976 can be reduced. Therefore, this structure is suitable for high-definition EL display devices.

[0135] Next, a method for fabricating the layer structure of the pixel shown in FIG. 6(B) and FIG. 6(C) will be described with reference to FIGS. 16. The top views are shown in FIG. 9(A), FIG. 10(A), FIG. 11(A), and FIG. 2(A), 13(A), 14(A), 15(A) and 16(A), The corresponding cross-sectional views are shown in Fig. 9(B), Fig. 10(B), Fig. 11(B), Fig. 12(B), and Fig. 3(B), FIG. 14(B), FIG. 15(B) and FIG. 16(B).

[0136] First, a conductive film 904a, a conductive film 904b, a conductive film 904c, and a conductive film 904 d, a conductive film 904e and a conductive film 904f are formed (see FIG. 9(A) and FIG. 9(B)). The conductive film 904a is a gate electrode of the scanning line GL3 and the transistor 975. The conductive film 904b functions as one electrode of the capacitor 976. The conductive film 904c functions as a power supply line PL2. As the gate electrodes of the scan line GL1 and the transistors 971 and 973 The conductive film 904e is connected to the scanning line GL2 and the gate electrode of the transistor 974. The conductive film 904f functions as a gate electrode of the transistor 972.

[0137] Next, an insulating film 912a is formed. Next, an insulating film 912b is formed on the insulating film 912a. Note that the insulating film 912a and the insulating film 912b are formed on the transistors 971 and 9 72, gate insulation of transistor 973, transistor 974 and transistor 975 It acts as a membrane.

[0138] Next, a semiconductor film 906, a semiconductor film 906a in the same layer as the semiconductor film 906, and a semiconductor film 906b, a semiconductor film 906c, and a semiconductor film 906d are formed (FIG. 10(A) and FIG. 10(B). Note that the semiconductor film 906 functions as a semiconductor film of a transistor 975. The semiconductor film 906a functions as a semiconductor film of the transistor 971. In addition, the semiconductor film 906b functions as a semiconductor film of the transistor 974. The film 906c functions as a semiconductor film of the transistor 973. functions as a semiconductor film of the transistor 972.

[0139] Next, an opening 928a reaching the conductive film 904b is formed in the insulating film 912a and the insulating film 912b. , an opening 928b reaching the conductive film 904c, and an opening 928f reaching the conductive film 904c. c is formed (see FIG. 11(A) and FIG. 11(B)).

[0140] Next, the conductive film 916a, the conductive film 916b, the conductive film 916c, the conductive film 916d, and the conductive film The conductive film 916d is formed by forming an opening 916e, a conductive film 916f, and a conductive film 916g. The conductive film 916f is electrically connected to the conductive film 904b through the opening 928a. The conductive film 916g is electrically connected to the conductive film 904c through the opening 9 28c and electrically connected to the conductive film 904f (see FIG. 11(A) and FIG. 11(B)). The conductive film 916a is a source electrode of the transistor 972 and a 5 and the other electrode of the capacitor 976. The conductive film 916b functions as a source electrode of the transistor 975. The conductive film 91 functions as a source electrode or a drain electrode of the transistor 971. 6d is a source electrode or drain electrode of the transistor 971 and a The conductive film 916e functions as a source electrode or a drain electrode of the transistor 4. The conductive film 916f functions as a drain electrode of the transistor 972. The conductive film 916g functions as a source electrode or a drain electrode of the transistor 3. A source electrode or drain electrode of the transistor 973 and a source electrode or drain electrode of the transistor 974 The gate electrode functions as a drain electrode.

[0141] Next, an insulating film 918a is formed. Next, an insulating film 918b is formed. Next, an insulating film 91 An opening 938 is formed in the insulating film 918a and the insulating film 918b, reaching the conductive film 916a. Next, An insulating film 918c is formed (see FIG. 12(A) and FIG. 12(B)). 18a, the insulating film 918b, and the insulating film 918c are 72, gate insulation of transistor 973, transistor 974 and transistor 975 It acts as a membrane.

[0142] Next, the insulating films 918a, 918b, and 918c are covered with a conductive film 916b. an opening 938b reaching the conductive film 916d; an opening 938c reaching the conductive film 916c; an opening 938d reaching the conductive film 916g; and an opening 938f reaching the conductive film 916e. An opening 938g is formed. In addition, the insulating films 912a, 912b, and 918a are An opening 938a reaching the conductive film 904a is formed in the insulating film 918b and the insulating film 918c. (See FIG. 13(A) and FIG. 13(B).)

[0143] Next, the conductive film 914a, the conductive film 914b, the conductive film 914c, and the conductive film 914d are formed. The conductive film 914a is electrically connected to the conductive film 904a through the opening 938a. In addition, the conductive film 914b is electrically connected to the conductive film 916d through the opening 938c. As described above, the conductive film 916d is electrically connected to the conductive film 904b. The conductive film 914b is electrically connected to the conductive film 904b. The conductive film 914d is electrically connected to the conductive film 904d through the opening 938e. 938f. Here, as described above, the conductive film 9 16g is electrically connected to the conductive film 904f. That is, the conductive film 914d is electrically connected to the conductive film 904f. Note that the conductive film 914a functions as a gate electrode of the transistor 975. The conductive film 914b functions as one electrode of the capacitor 976. The conductive film 914c functions as gate electrodes of the transistors 971 and 973. The conductive film 914d functions as a gate electrode of the transistor 972.

[0144] Next, an insulating film 908 is formed. Next, an opening portion overlapping the opening portion 938b is formed in the insulating film 908. 948a, an opening 948b overlapping with opening 938g, and an opening 948c overlapping with opening 938d. Form 948c (see Figures 14(A) and 14(B)).

[0145] Next, the conductive film 926a, the conductive film 926b, and the conductive film 926c are formed. a is electrically connected to the conductive film 916c through the opening 948c. b is electrically connected to the conductive film 916b through the opening 948a. The conductive film 926c is electrically connected to the conductive film 916e through the opening 948b. The conductive film 926a functions as a signal line, and the conductive film 926c functions as a power supply line PL1.

[0146] Figures 14(A) and 14(B) correspond to Figures 6(B) and 6(C). The subsequent method for manufacturing the EL display device is shown in FIG. 15 and FIG.

[0147] An insulating film is formed on the insulating film 908, the conductive film 926a, the conductive film 926b, and the conductive film 926c. Next, an opening 958 is formed in the insulating film 928, the opening reaching the conductive film 926b. (See FIG. 15(A) and FIG. 15(B)).

[0148] Next, the conductive film 934 is formed. The conductive film 934 is formed by arranging the conductive film 926b through the opening 958. (see FIG. 15A and FIG. 15B). Note that the conductive film 934 , which functions as one electrode of the light-emitting element 919 .

[0149] Next, a transparent film 932 having a function of transmitting or semi-transmitting visible light is formed (FIG. 16( See FIG. 16(A) and FIG. 16(B). By forming the transparent film 932, the resonance effect of light is utilized. A micro-optical resonator (microcavity) structure can be formed, and the light emitting element 919 can be extracted. The peak of the emission spectrum can be made steep and intense. By including the film 932, the luminance and color purity of the EL display device can be improved. It is preferable that the thickness (number of layers) and type of the transparent film 932 be changed for each emitted color of the pixel. However, the transparent film 932 does not necessarily have to be formed.

[0150] Next, an insulating film 936 is formed. The insulating film 936 has an opening 968 which becomes a light-emitting region of a pixel. (see FIG. 16A and FIG. 16B). The insulating film 936 functions as a partition wall. .

[0151] Next, the spacers 940 are formed (see FIGS. 16(A) and 16(B)).

[0152] Then, a light-emitting layer, a conductive film that functions as the other electrode of the light-emitting element 919, etc. are formed. The EL display device can be manufactured with high resolution and high display quality. It is a simple EL display device.

[0153] In the following, the gate voltage of the transistor 972 during the period T3 of the pixel shown in FIG. The value of Vgs was calculated. The calculation was performed using an analog circuit simulator manufactured by SILVACO. The SmartSpice simulator and Clever high-precision 3D parasitic element extraction tool are Used.

[0154] First, the parasitic capacitance in the pixel was extracted using Clever. The thickness of each film is shown in Table 1 below.

[0155] [Table 1]

[0156] The extraction of the parasitic capacitance was performed until the error of the iterative calculation was within 5%. The D structure was set to MANHATTAN-TYPE in GEOMETRICAL MODE. The circuit size is a matrix of 3 pixels vertically and 3 pixels horizontally.

[0157] The value of the gate voltage Vgs of the transistor 972 during the period T3 of the pixel shown in FIG. The calculation is done by taking the difference Vdata between the potential Vdata of the signal line SL and the potential V0 of the power line PL2. -V0 is set to -1V (condition 1), -0.5V (condition 2), 0V (condition 3), 0.5V (condition 4), 1V (condition 5), and 1.5V (condition 6). The potential values ​​are: the potential Vano of the power line PL1 is 10 V, and the potential of the other electrode of the light emitting element 919 is Vcat was set to -4V, the potential GVDD was set to 15V, and the potential GVSS was set to -5V. VDD is the high-level voltage supplied to the scan lines GL1, GL2, and GL3, respectively. The potential GVSS corresponds to the potential of the scanning line GL1, the scanning line GL2, and the scanning This corresponds to a low level potential applied to the line GL3.

[0158] In addition, the channel length L and channel width W of each transistor in the calculation are In transistor 1, the channel length L is 2 μm and the channel width W is 1.5 μm. The channel length L is 6 μm and the channel width W is 2 μm. In the transistor 973, the channel length L is 2 μm. m, channel width W is 1.5 μm, channel length L is 3 μm in transistor 974, The channel width W is 1.5 μm, and the channel length L is 2 μm and the channel width W is 2 In addition, the source voltage of all the transistors in the pixel shown in FIG. The region where the conductive film and the semiconductor film, which function as a gate electrode or drain electrode, are in contact with each other, The length of the channel length in the area where the electrode is formed and the area where the electrode overlaps is 0.75 μm. The value was m.

[0159] During the period T3, the gate voltage Vgs of the transistor 972 is Vdata-V0+Vth. Therefore, in the pixel shown in FIG. 6, Vgs-Vth=Vdata-V0. , Vgs-Vth ideally has a constant value regardless of the value of the threshold voltage Vth. He explained that:

[0160] FIG. 17 shows the Vgs-Vth and threshold voltages obtained by calculation under conditions 1 to 6. In FIG. 17, the horizontal axis represents the threshold voltage Vth (V) and the vertical axis represents Vgs -Vth(V). From FIG. 17, even if the value of the threshold voltage Vth changes, , the Vgs-Vth variation is smaller than that without threshold voltage correction (see the dashed line in Figure 17). It can be seen that the amount of heat is kept to around 45%.

[0161] From the above calculation results, in the EL display device according to one embodiment of the present invention, Even if there is a variation or fluctuation in the threshold voltage Vth, the effect of this is reduced. It can be seen that the gate voltage Vgs of the transistor 972 can be corrected.

[0162] <Drive circuit> FIG. 22 illustrates an example of a scanning line driver circuit that can be used in a display device according to one embodiment of the present invention. In addition, a shift register (also referred to as G_SR), which is a component of the scanning line driving circuit, The terminal of the inverter (also written as G2_INV) connected to wire G2 and the terminal of wire G3 The terminal position of the inverter (also written as G3_INV) to be connected is shown in Fig. 23(A), 23(B) and 23(C), respectively.

[0163] 24 and 25 show a circuit that can be used as the shift register shown in FIG. 23(A). The circuit is also shown in FIG. 26 and FIG. 27. The second gate electrode may be provided in the first gate electrode. The second gate electrode is electrically connected to the first gate electrode. The transistor has a higher on-current than a transistor of the same size that does not have a second gate electrode. Therefore, even if the voltage amplitude of the output signal is increased, the occupancy rate of the scanning line driving circuit is The area can be reduced. Also, FIG. 28(A) and FIG. 28(B) show the layout It can be used as an inverter connected to the line G2 and an inverter connected to the line G3. The figure shows a circuit that can be used to control the G_VDD, G_VCC1, and G_VCC2 high power supply voltages. Also, G_VSS, G_VEE1, G_VEE2 and G_VEE3 are low power supplies. The potential is shown.

[0164] The scanning line driver circuit shown in FIG. 22 is applied with the timing chart shown in FIG. , can be operated.

[0165] <Oxide semiconductor film> Among the semiconductor films that can be used in one embodiment of the present invention, an oxide semiconductor film will be described below. He explains.

[0166] The oxide semiconductor film is an oxide containing indium. In addition, the oxide semiconductor film contains the element M, and the carrier mobility (electron mobility) is increased. The element M is preferably, for example, aluminum, gallium, yttrium, or sulphur. The element M is, for example, an element that has a high bond energy with oxygen. The element M is For example, it is an element that has the function of increasing the energy gap of the oxide. It is preferable that the oxide semiconductor film contains zinc. When the oxide contains zinc, for example, The energy of the top of the valence band of the oxide varies depending on the ratio of the number of zinc atoms, for example. can be controlled.

[0167] However, the oxide semiconductor film is not limited to an oxide containing indium. For example, Zn--Sn oxide or Ga--Sn oxide may be used.

[0168] In addition, an oxide having a large energy gap is used for the oxide semiconductor film. The energy gap is, for example, 2.5 eV or more and 4.2 eV or less, preferably 2.8 eV. The excitation voltage is set to 3.8 eV or less, and more preferably 3 eV or more and 3.5 eV or less.

[0169] In addition, when the oxide semiconductor film is formed by a sputtering method, in order to reduce the number of particles, It is preferable to use a target containing indium. In addition, an oxide having a high atomic ratio of element M is used. When using a target, the conductivity of the target may be reduced. When a target is used, the conductivity of the target can be increased, and DC discharge and AC discharge can be used. This makes it easier to handle large-area substrates. can be increased.

[0170] When an oxide semiconductor film is formed by a sputtering method, the atomic ratio of a target is In:M Zn is 3:1:1, 3:1:2, 3:1:4, 1:1:0.5, 1:1:1, 1:1: 2, and so on.

[0171] When an oxide semiconductor film is formed by a sputtering method, the atomic ratio of the target is deviated. In particular, zinc has a higher atomic ratio in the film than the atomic ratio in the target. The ratio of the number of atoms of zinc contained in the target may become smaller. It may be between 0 atomic% and 90 atomic%.

[0172] The influence of impurities in an oxide semiconductor film will be described below. In order to stabilize the electrical characteristics of the capacitor, it is necessary to reduce the impurity concentration in the oxide semiconductor film and to obtain a low-carrier It is effective to increase the carrier density and the purity of the oxide semiconductor film. , 1×10 17 pieces / cm 3 Less than 1×10 15 pieces / cm 3 Less than or equal to 1 × 10 13 pieces / cm 3 In order to reduce the impurity concentration in the oxide semiconductor film, It is also preferable to reduce the impurity concentration.

[0173] For example, silicon in the oxide semiconductor film can become a carrier trap or a carrier generation source. Therefore, the silicon concentration between the oxide semiconductor film and the adjacent insulating film is Secondary Ion Mass Spectroscopy (SIMS) In terms of the NMR spectrum, the 19 atoms / cm 3 Less than 5 x 10 1 8 atoms / cm 3 less than 2×10 18 atoms / cm 3 Less than do.

[0174] Furthermore, when hydrogen is contained in the oxide semiconductor film, the carrier density may be increased. The hydrogen concentration in the oxide semiconductor film was measured by SIMS at 2×10 20 atoms / cm 3 Below Lower, preferably 5 x 10 19 atoms / cm 3 Less than or equal to 1×10 19 at oms / cm 3 Less than 5×10, more preferably 18 atoms / cm 3 The following is as follows. In addition, when nitrogen is contained in the oxide semiconductor film, the carrier density may be increased. The nitrogen concentration of the oxide semiconductor film was 5×10 19 atoms / cm 3 Not yet Less than 5×10 18 atoms / cm 3 Less than or equal to 1×10 18 at oms / cm 3 Less than 5×10, more preferably 17 atoms / cm 3 The following applies.

[0175] In order to reduce the hydrogen concentration in the oxide semiconductor film, the hydrogen concentration in the adjacent insulating film is reduced. The hydrogen concentration of the adjacent insulating film is preferably 2×10 20 atoms / cm 3Less than or equal to 5×10 19 atoms / cm 3 Less than or equal to 1×1, more preferably 0 19 atoms / cm 3 Less than 5×10, more preferably 18 atoms / cm 3 below In order to reduce the nitrogen concentration in the oxide semiconductor film, the nitrogen concentration in the adjacent insulating film is The nitrogen concentration of the adjacent insulating film is preferably reduced by 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 The following is more preferred: 1×10 18 atoms / cm 3 Less than 5×10, more preferably 17 atoms / cm 3 The following applies.

[0176] The structure of the oxide semiconductor film will be described below.

[0177] Oxide semiconductor films are roughly classified into non-single-crystal oxide semiconductor films and single-crystal oxide semiconductor films. The single-crystal oxide semiconductor film is called CAAC-OS (C Axis Aligned Crystalline Oxide Semiconductor). Talline Oxide Semiconductor film, polycrystalline oxide semiconductor film The oxide semiconductor film includes a microcrystalline oxide semiconductor film, an amorphous oxide semiconductor film, and the like.

[0178] First, we will explain the CAAC-OS film.

[0179] The CAAC-OS film is one of the oxide semiconductor films that has multiple crystal parts. The crystal part is so large that it fits inside a cube with one side less than 100 nm. Therefore, CAAC The crystal parts contained in the -OS film are cubic with one side less than 10 nm, 5 nm, or 3 nm. This includes cases where the size is small enough to fit inside the body.

[0180] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a ferromagnetic microscope, clear boundaries between the crystals, i.e., crystal boundaries, were observed. It is not possible to confirm the grain boundary. It can be said that the AC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0181] The CAAC-OS film was observed by TEM from a direction approximately parallel to the sample surface (cross-sectional TEM observation). It can be seen that the metal atoms are arranged in layers in the crystals. Each layer reflects the unevenness of the surface on which the CAAC-OS film is formed (also called the surface on which the film is formed) or the upper surface. The CAAC-OS film has a shape similar to that of the crystalline silicon film, and is arranged parallel to the surface on which the CAAC-OS film is formed or the upper surface.

[0182] On the other hand, the CAAC-OS film was observed by TEM from a direction almost perpendicular to the sample surface (planar TEM). When observed, it was found that the metal atoms in the crystals were arranged in triangular or hexagonal shapes. However, there is no regularity in the arrangement of metal atoms between different crystal parts. .

[0183] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It is clear that there are

[0184] X-ray diffraction (XRD) was performed on the CAAC-OS film. For example, a CAAC-OS film with InGaZnO4 crystals was In the out-of-plane analysis, a peak was observed at a diffraction angle (2θ) of approximately 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. From this, it can be seen that the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis is approximately aligned on the surface on which the film is formed or on the upper surface. You can see that it is oriented vertically.

[0185] In this specification, when the crystal is a trigonal or rhombohedral crystal, it is represented as a hexagonal crystal system. .

[0186] On the other hand, in-pla, X-rays are incident on the CAAC-OS film from a direction almost perpendicular to the c-axis. In the NE method, a peak may appear at 2θ of around 56°. This peak is It is attributed to the (110) plane of the InGaZnO4 crystal. Single crystal oxide of InGaZnO4 In the case of a semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is set as the axis (φ axis). When the sample is rotated and analyzed (φ scan), the crystal plane equivalent to the (110) plane is obtained. In contrast, in the case of the CAAC-OS film, 2θ is set at 56 Even when φ is fixed at around 100° and scanned, no clear peak appears.

[0187] From the above, it is considered that the a-axis and b-axis orientations are inconsistent between different crystal regions in the CAAC-OS film. The crystal is regular, but has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface on which the crystal is formed or the upper surface. Therefore, the layered structure confirmed by the cross-sectional TEM observation mentioned above is consistent with the Each layer of metal atoms arranged in a plane is parallel to the ab plane of the crystal.

[0188] The crystalline portion is formed when the CAAC-OS film is formed or when a crystallization process such as a heat treatment is performed. As described above, the c-axis of the crystal is aligned along the surface on which the CAAC-OS film is formed or along the surface on which the CAAC-OS film is formed. is oriented in a direction parallel to the normal vector of the top surface. When the shape of the CAAC-OS film is changed by etching, the c-axis of the crystal is changed to the shape of the CAAC-OS film. It may not be parallel to the normal vector of the top or bottom surface.

[0189] In addition, the degree of crystallinity in the CAAC-OS film may not be uniform. When the crystal part of the CAAC-OS film is formed by crystal growth from the vicinity of the top surface, The adjacent regions may have a higher degree of crystallinity than the regions adjacent the surface to be formed. When impurities are added to a C-OS film, the crystallinity of the region to which the impurities are added changes, resulting in partial In some cases, regions of differing crystallinity may be formed.

[0190] In addition, the out-of-plane method of CAAC-OS film with InGaZnO4 crystals In the analysis by , in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ of around 36° may be due to the c-axis orientation in some parts of the CAAC-OS film. The CAAC-OS film contains crystals that do not have a 2θ of around 31°. It is preferred that the spectrum exhibits a peak and does not exhibit a peak at 2θ of around 36°.

[0191] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. The impurities include hydrogen, carbon, and The elements are other than the main components of the oxide semiconductor film, such as silicon and transition metal elements. The elements that bond to oxygen more strongly than the metal elements that form the oxide semiconductor film, such as arsenic, are oxidized. By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide have an atomic radius of Since the molecular radius is large, when the cation is contained in the oxide semiconductor film, the The impurities in the oxide semiconductor film may cause the atomic arrangement to be disturbed, which may result in a decrease in crystallinity. Objects can act as carrier traps or carrier generation sources.

[0192] The CAAC-OS film is an oxide semiconductor film having a low density of defect states. Oxygen vacancies in the semiconductor film can become carrier traps or trap hydrogen, It can be a carrier source.

[0193] A material with a low impurity concentration and a low defect level density (few oxygen vacancies) is called a high-purity intrinsic or The term "substantially high-purity intrinsic" refers to a highly-purified intrinsic oxide semiconductor film. Since there are fewer carrier generation sources, the carrier density can be reduced. The transistor including the oxide semiconductor film has electrical characteristics in which the threshold voltage is negative ( Also called normally-on.) In addition, high purity intrinsic or substantially high purity The highly intrinsic oxide semiconductor film has few carrier traps. The transistors using the thin film have small fluctuations in electrical characteristics and are highly reliable. Note that it takes a certain time for charges trapped in the carrier traps in the oxide semiconductor film to be released. The time when the charge is released is long, and it may behave as if it is a fixed charge. A transistor using an oxide semiconductor film having a high density of defect states has unstable electrical characteristics. This may be the case.

[0194] In addition, the electrical characteristics of transistors using CAAC-OS films were improved by irradiation with visible light or ultraviolet light. The fluctuation is small.

[0195] Next, a microcrystalline oxide semiconductor film will be described.

[0196] In the microcrystalline oxide semiconductor film, crystal parts can be clearly seen in the TEM image. The crystal parts contained in the microcrystalline oxide semiconductor film may have a size of 1 nm or more and 100 nm or less. In particular, the size of the particles is between 1 nm and 10 nm. Nanocrystals (nc) are microcrystals with a diameter of 1 nm or less and 3 nm or less. The oxide semiconductor film having Al was formed by The nc-OS film is called a TE semiconductor film. In the M image, the grain boundaries may not be clearly visible.

[0197] The nc-OS film is a microscopic region (e.g., a region of 1 nm to 10 nm, especially a region of 1 nm or more). The atomic arrangement has periodicity in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystal parts. Therefore, no orientation is observed overall. Therefore, the nc-OS film cannot be distinguished from an amorphous oxide semiconductor film depending on the analysis method. For example, XRD, which uses X-rays with a diameter larger than that of the crystal part, is used for nc-OS films. When structural analysis is performed using the out-of-plane method, the crystal planes are In addition, the nc-OS film has a larger probe diameter (e.g., Electron beam diffraction (also called selected area electron beam diffraction) is performed using an electron beam with a diameter of 50 nm or more. On the other hand, for the nc-OS film, Probe diameter close to or smaller than the size of the crystal part (e.g., 1 nm to 30 nm) When electron beam diffraction (also called nanobeam electron beam diffraction) is performed using an electron beam of In addition, when nanobeam electron diffraction is performed on the nc-OS film, a circular pattern is observed. In some cases, bright areas (ring-shaped) were observed. When performing electron beam diffraction, multiple spots may be observed within a ring-shaped region. .

[0198] The nc-OS film is an oxide semiconductor film that has higher order than an amorphous oxide semiconductor film. Therefore, the nc-OS film has a lower density of defect states than the amorphous oxide semiconductor film. In the nc-OS film, there is no regularity in the crystal orientation between different crystal parts. The S film has a higher density of defect states than the CAAC-OS film.

[0199] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, or a CA The AC-OS film may include two or more kinds of films.

[0200] The oxide semiconductor film may be a stacked film of oxide semiconductor films. For example, the oxide semiconductor film , a two-layer structure, or a three-layer structure.

[0201] For example, a case where the oxide semiconductor film has a three-layer structure will be described.

[0202] The second layer (middle layer) is described in the above description of the oxide semiconductor film. The third layer (upper layer) is made up of one or more elements other than oxygen that make up the second layer, or two or more elements. The second layer is an oxide semiconductor film composed of one or more elements other than oxygen. Since the first and third layers are composed of more than one species, the interface between the first and second layers and the interface between the second layer and the At the interface between the first and third layers, an interface state is unlikely to be formed.

[0203] When the first layer is an In-M-Zn oxide, the sum of In and M is 100 atomic %. In this case, preferably, In is less than 50 atomic % and M is more than 50 atomic %. More preferably, In is less than 25 atomic % and M is more than 75 atomic %. In addition, when the second layer is an In-M-Zn oxide, the sum of In and M is 100 atoms. When the atomic percentage is ic%, it is preferable that In is higher than 25 atomic percent and M is 75 atomic percent. c%, more preferably In is higher than 34 atomic % and M is 66 atomic %. When the third layer is an In-M-Zn oxide, the sum of In and M must be less than 100%. atomic%, In is less than 50 atomic%, M is more than 50 atomic%, More preferably, In is less than 25 atomic % and M is more than 75 atomic %. The third layer may be made of the same oxide as the first layer.

[0204] Here, there may be a mixed region of the first and second layers between the first and second layers. In addition, there may be a mixed region between the second and third layers. The interface state density is low in the interlayer. Therefore, the first, second and third layers are stacked. , near each interface, the energy changes continuously (also called continuous junction). It has a band structure.

[0205] The second layer is made of an oxide with a higher electron affinity than the first and third layers. As a target, the electron affinity is preferably 0.07 eV or more and 1.3 eV or less than that of the first and third layers. Preferably, the value is 0.1 eV or more and 0.7 eV or less, and more preferably, the value is 0.15 eV or more and 0.4 eV or less. The electron affinity is calculated by the relationship between the vacuum level and the energy at the bottom of the conduction band. This is the difference.

[0206] When an electric field is applied to the gate electrode, the electron affinity of the first, second, and third layers is A channel is formed in the second layer, where the density is large.

[0207] In order to increase the on-current of the transistor, the thickness of the third layer is preferably as small as possible. For example, the third layer is less than 10 nm, preferably 5 nm or less, and more preferably 3 nm. On the other hand, the third layer is an insulating film adjacent to the second layer where the channel is formed. It has the function of blocking elements other than oxygen (such as silicon) from entering. Therefore, it is preferable that the third layer has a certain thickness. For example, the thickness of the third layer is 0 It is preferably 0.3 nm or more, more preferably 1 nm or more, and even more preferably 2 nm or more.

[0208] In order to improve reliability, it is preferable that the first layer is thick and the third layer is thin. The thickness of the first layer is 20 nm or more, preferably 30 nm or more, and more preferably 40 nm or more. The thickness of the first layer is 20 nm or more, preferably 60 nm or more. The thickness is preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 60 nm or more. The distance from the interface between the first layer and the adjacent insulating film to the second layer where the channel is formed is 20 nm. or more, preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 60 nm or more. However, since this may reduce the productivity of semiconductor devices, The mesh thickness is 200 nm or less, preferably 120 nm or less, and more preferably 80 nm or less. Below.

[0209] For example, the silicon concentration between the first and second layers is 1×10 1 9 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to Preferably 2 x 10 18 atoms / cm 3 In addition, between the second and third layers, The silicon concentration in the sample was measured by SIMS at 1×10 19 atoms / cm 3 Less than, preferred 5×10 18 atoms / cm 3 less than 2×10 18 atoms / cm 3 Less than.

[0210] In addition, in order to reduce the hydrogen concentration in the second layer, the hydrogen concentrations in the first and third layers were reduced. The hydrogen concentration in the first and third layers is preferably 2×10 20 atoms / cm 3 Less than or equal to 5×10 19 atoms / cm 3 Less than or equal to 1×1, more preferably 0 19 atoms / cm 3 Less than 5×10, more preferably 18 atoms / cm 3 below In order to reduce the nitrogen concentration in the second layer, the nitrogen concentrations in the first and third layers are set low. The nitrogen concentration in the first and third layers is preferably 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 The following is more preferred: 1×10 18 atoms / cm 3 Less than 5×10, more preferably 17 atoms / cm 3 The following applies.

[0211] The above three-layer structure is just an example. For example, a two-layer structure without the first or third layer may be used. do not have.

[0212] <module> A display module to which the semiconductor device of one embodiment of the present invention is applied will be described below with reference to FIG. Explanations will be given.

[0213] The display module 8000 shown in FIG. 18 is made up of an upper cover 8001 and a lower cover 8002. In between, touch panel 8004 is connected to FPC8003, and touch panel 8005 is connected to FPC8005. Display panel 8006, backlight unit 8007, frame 8009, printed circuit board 8010 and a battery 8011. In some cases, the controller 8002 may not have the read / write head 8011 or the touch panel 8004.

[0214] The semiconductor device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0215] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel. The shape and dimensions can be changed appropriately to match the size of the cable 8006.

[0216] The touch panel 8004 is a resistive or capacitive touch panel, and the display panel 8 8006. In addition, the opposing substrate (sealing substrate) of the display panel 8006 It is also possible to provide the display panel 8 with a touch panel function. It is also possible to provide an optical sensor in each pixel of the touch panel to make it an optical touch panel. Alternatively, a touch sensor electrode is provided in each pixel of the display panel 8006, and a capacitive touch sensor is provided. It is also possible to use it as a chip panel.

[0217] The backlight unit 8007 includes a light source 8008. It may be provided at the end of the unit 8007 and may be configured to use a light diffusion plate.

[0218] The frame 8009 protects the display panel 8006 and also prevents the operation of the printed circuit board 8010. The device may also have a function as an electromagnetic shield for blocking electromagnetic waves generated by the device. The frame 8009 may also function as a heat sink.

[0219] 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 circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. In some cases, the battery 8011 may not be required.

[0220] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may be added.

[0221] <Electronic equipment> Examples of electronic devices and lighting devices to which the display device of one embodiment of the present invention is applied will be described below with reference to FIGS. The description will be given with reference to the surface.

[0222] As an example of an electronic device to which a display device having a flexible shape is applied, a television Television equipment (also called televisions or television receivers), computer monitors, displays, etc. Digital cameras, digital video cameras, digital photo frames, mobile information terminals (mobile phones) (also called mobile phone devices), portable game machines, portable information terminals, audio playback devices, pachinko machines Examples of such machines include large game consoles.

[0223] In addition, lighting devices and display devices can be mounted on the interior or exterior walls of houses and buildings, and on the interior or exterior of automobiles. It is also possible to incorporate the device along a curved surface.

[0224] FIG. 19A shows an example of a portable information terminal. The portable information terminal 7400 has a housing 74 In addition to the display unit 7402 incorporated in the 01, the operation buttons 7403 and the external connection port 7404 , a speaker 7405, a microphone 7406, etc. The LCD panel is manufactured by using a display device for the display portion 7402.

[0225] In the portable information terminal 7400 shown in FIG. 19A, when the display portion 7402 is touched with a finger or the like, You can also make calls, enter text, and perform any other functions. The operation can be performed by touching the display portion 7402 with a finger or the like.

[0226] In addition, by operating the operation button 7403, the power can be turned on and off, and the display unit 7402 can be displayed. For example, you can change the type of image displayed from the main menu to the email composition screen. You can switch to the screen.

[0227] Here, the display device of one embodiment of the present invention is incorporated in the display portion 7402. As a result, a highly reliable portable information terminal can be provided with a curved display section.

[0228] FIG. 19B shows an example of a wristband-type display device. The device includes a housing 7101, a display unit 7102, an operation button 7103, and a transmitting / receiving device 7104. Prepare.

[0229] The portable display device 7100 can receive a video signal by a transmitting / receiving device 7104. Video can be displayed on the display unit 7102. Audio signals can also be sent to other receiving devices. It is also possible.

[0230] In addition, the operation button 7103 can be used to turn the power on and off and to switch the image to be displayed. , or adjust the volume of the audio.

[0231] Here, the display device of one embodiment of the present invention is incorporated in the display portion 7102. As a result, a highly reliable portable display device can be provided with a curved display portion.

[0232] 19(C) and 19(D) show an example of a lighting device. The lighting device 7220 includes a base 7201 having an operation switch 7203 and a base 720 The light emitting portion is supported by the light emitting element.

[0233] The light-emitting portion 7212 of the lighting device 7210 shown in FIG. 19C has two convexly curved The light emitting parts are arranged symmetrically. It can illuminate the direction.

[0234] The lighting device 7220 shown in FIG. 19(D) includes a light-emitting portion 7222 that is curved in a concave shape. Therefore, in order to collect light emitted from the light emitting unit 7222 on the front surface of the lighting device 7220, It is suitable for brightly lighting an area.

[0235] In addition, the light-emitting units of the lighting device 7210 and the lighting device 7220 are flexible. Since the light emitting part has a plastic member or a movable frame, the light emitting part is fixed to the plastic member or a movable frame. The light emitting surface of the light emitting portion may be configured to be freely curved according to the process.

[0236] Here, the light emitting units of the lighting device 7210 and the lighting device 7220 are each provided with the The display device according to one embodiment is incorporated in the display device. Therefore, the display device has a curved display portion and is reliable. It is possible to provide a lighting device with high performance.

[0237] FIG. 20A shows an example of a portable display device. The display device 7300 includes a housing 7301, It includes a display unit 7302, an operation button 7303, a pull-out member 7304, and a control unit 7305. .

[0238] The display device 7300 is a flexible display unit wound in a roll in a cylindrical housing 7301. The display portion 7302 includes a first substrate on which a light-shielding layer and the like are formed, and a transistor. The display portion 7302 is disposed in the housing 7301. It is always wrapped so that the second substrate is on the outside.

[0239] In addition, the display device 7300 can receive a video signal through the control unit 7305. The control unit 7305 is provided with a battery. In addition, the control unit 7305 is equipped with a connector, and is configured to directly supply video signals and power. This is also fine.

[0240] In addition, the operation button 7303 can be used to turn the power on and off and to switch the image to be displayed. etc. can be carried out.

[0241] FIG. 20B shows a state in which the display portion 7302 is pulled out by a pull-out member 7304 . In this state, an image can be displayed on the display portion 7302. The positioned operation button 7303 allows easy operation with one hand.

[0242] In order to prevent the display unit 7302 from bending when the display unit 7302 is pulled out, A frame for reinforcement may be provided at the end of 2.

[0243] In addition to this configuration, a speaker is provided on the housing, and the audio signal received together with the video signal is output. The configuration may be such that sound is outputted.

[0244] The display device of one embodiment of the present invention is incorporated in the display portion 7302. Since the unit 7302 is a flexible and reliable display device, the display device 7300 A lightweight and highly reliable display device can be obtained.

[0245] Note that the display device of one embodiment of the present invention can be used in the electronic devices and lighting devices described above. It goes without saying that there is no particular limitation.

[0246] The configurations and methods shown in the embodiments may be used in combination with other configurations and methods shown in the embodiments. They can be used in any suitable combination. EXAMPLES

[0247] In this example, an EL display device according to one embodiment of the present invention was manufactured.

[0248] Table 2 shows the specifications of the EL display device.

[0249] [Table 2]

[0250] The EL display device according to one embodiment of the present invention can display nearly 500 million pixels in a 13.3-inch display area. It also has a high aperture ratio of over 40%.

[0251] The EL display device has the scanning line driving circuit shown in FIG. The positions of the inverter terminals to be connected to wire G3 and the inverter terminals to be connected to wire G4 are shown in Figure 23 ( 23(A), 23(B) and 23(C), respectively. The shift register shown in FIG. 26 was used as a component of the operating circuit.

[0252] Figure 30 shows the output waveform of the scanning line driver circuit. The clock frequency shown by GCK1 is 64. At this time, the amplitude voltage of the output signal on the wiring G1 was approximately 20V. That is, the EL display device manufactured in this embodiment can sufficiently connect the wiring G1 even during a short selection period. You can see that it is charging.

[0253] FIG. 21 shows a photograph of the EL display device. FIG. 31 shows the color coordinates of each of the RGB colors of the EL display device. From Fig. 31, we can see that the NTSC ratio is higher than 84%. 31, the EL display device fabricated in this example has a high element density, but It can be seen that the display has excellent quality. [Explanation of symbols]

[0254] 100 Substrates 104 Conductive film 112 Insulating film 114 Conductive Film 116 Conductive Film 118 Insulating film 700 Substrates 704a Conductive film 704b Conductive film 706 Semiconductor Film 707 Semiconductor Film 712a Insulating film 712b Insulating film 714a Conductive film 714b Conductive film 716a Conductive film 716b Conductive film 718a Insulating film 718b Insulating film 718c Insulating film 719 Light emitting element 720 Insulating film 721 Insulating film 731 Terminal 732 FPC 733a Wiring 734 Sealing material 735 Drive Circuit 736 Drive Circuit 737 pixels 741 Transistor 742 Capacitive element 743 Switching element 744 Signal Line 750 Board 751 Transistor 752 Capacitive element 753 Liquid crystal element 754 scan lines 755 Signal Line 781 Conductive Film 782 Light-emitting layer 783 Conductive Film 784 Bulkhead 791 Conductive Film 792 Insulating film 793 Liquid crystal layer 794 Insulating film 795 Spacer 796 Conductive Film 797 Circuit Board 900 Substrate 904a Conductive film 904b Conductive film 904c conductive film 904d Conductive film 904e conductive film 904f conductive film 906 Semiconductor Film 906a Semiconductor film 906b Semiconductor film 906c Semiconductor film 906d Semiconductor film 908 Insulating film 912a Insulating film 912b Insulating film 914a Conductive film 914b Conductive film 914c conductive film 914d Conductive film 916a Conductive film 916b Conductive film 916c Conductive film 916d Conductive film 916e Conductive film 916f Conductive film 916g Conductive film 918a Insulating film 918b Insulating film 918c Insulating film 919 Light emitting element 926a Conductive film 926b Conductive film 926c conductive film 928 Insulating film 928a opening 928b opening 928c opening 932 Transparent membrane 934 Conductive film 936 Insulating film 938 Opening 938a opening 938b opening 938c opening 938d opening 938e opening 938f opening 938g opening 940 Spacer 948a opening 948b opening 948c opening 958 Opening 968 Opening 971 Transistor 972 Transistors 973 Transistor 974 Transistors 975 Transistors 976 Capacitor 7100 Portable display devices 7101 Case 7102 Display section 7103 Operation button 7104 Transmitting and receiving equipment 7201 Daibu 7203 Operation switch 7210 Lighting equipment 7212 Light emitting part 7220 Lighting Equipment 7222 Light emitting part 7300 display device 7301 Case 7302 Display section 7303 Operation button 7304 Materials 7305 Control Unit 7400 Mobile Information Terminal 7401 Case 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Mike 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8007 Backlight unit 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

1. A semiconductor device including a first transistor and a capacitor electrically connected to one of a source and a drain of the first transistor, A first conductive film; a first insulating film having a region located above the first conductive film; a first oxide semiconductor film having a region located above the first insulating film; a second oxide semiconductor film having a region located above the first insulating film; a second insulating film having a region located above the first oxide semiconductor film and a region located above the second oxide semiconductor film; a third insulating film having a region located above the second insulating film; a second conductive film having a region located above the second oxide semiconductor film with the second insulating film and the third insulating film interposed therebetween; having the first oxide semiconductor film includes a channel formation region of the first transistor, the channel formation region has a region overlapping the second insulating film and the third insulating film, the second oxide semiconductor film has a first region that overlaps with the second conductive film without the second insulating film and through the third insulating film; the first region has a region overlapping the first conductive film via the first insulating film, the first region functions as one electrode of the capacitor element; the first conductive film and the second conductive film are electrically connected to each other and function as the other electrode of the capacitance element; Semiconductor device.

2. A semiconductor device including a first transistor and a capacitor electrically connected to one of a source and a drain of the first transistor, A first conductive film; a first insulating film having a region located above the first conductive film; a first oxide semiconductor film having a region located above the first insulating film; a second oxide semiconductor film having a region located above the first insulating film; a second insulating film having a region in contact with an upper surface of the first oxide semiconductor film and a region in contact with an upper surface of the second oxide semiconductor film; a third insulating film having a region located above the second insulating film; a second conductive film having a region located above the second oxide semiconductor film with the second insulating film and the third insulating film interposed therebetween; having the first oxide semiconductor film includes a channel formation region of the first transistor, the channel formation region has a region overlapping the second insulating film and the third insulating film, the second oxide semiconductor film has a first region that overlaps with the second conductive film without the second insulating film and through the third insulating film; the first region has a region overlapping the first conductive film via the first insulating film, the first region functions as one electrode of the capacitor element; the first conductive film and the second conductive film are electrically connected to each other and function as the other electrode of the capacitance element; Semiconductor device.

3. A semiconductor device including a first transistor, a capacitor electrically connected to one of a source or a drain of the first transistor, and a second transistor having one of a source or a drain electrically connected to a gate of the first transistor, A first conductive film; a first insulating film having a region located above the first conductive film; a first oxide semiconductor film having a region located above the first insulating film; a second oxide semiconductor film having a region located above the first insulating film; a second insulating film having a region located above the first oxide semiconductor film and a region located above the second oxide semiconductor film; a third insulating film having a region located above the second insulating film; a second conductive film having a region located above the second oxide semiconductor film with the second insulating film and the third insulating film interposed therebetween; having the first oxide semiconductor film includes a channel formation region of the first transistor, the channel formation region has a region overlapping the second insulating film and the third insulating film, the second oxide semiconductor film has a first region that overlaps with the second conductive film without the second insulating film and through the third insulating film; the first region has a region overlapping the first conductive film via the first insulating film, the first region functions as one electrode of the capacitor element; the first conductive film and the second conductive film are electrically connected to each other and function as the other electrode of the capacitance element; Semiconductor device.

4. A semiconductor device including a first transistor, a capacitor electrically connected to one of a source or a drain of the first transistor, and a second transistor having one of a source or a drain electrically connected to a gate of the first transistor, A first conductive film; a first insulating film having a region located above the first conductive film; a first oxide semiconductor film having a region located above the first insulating film; a second oxide semiconductor film having a region located above the first insulating film; a second insulating film having a region in contact with an upper surface of the first oxide semiconductor film and a region in contact with an upper surface of the second oxide semiconductor film; a third insulating film having a region located above the second insulating film; a second conductive film having a region located above the second oxide semiconductor film with the second insulating film and the third insulating film interposed therebetween; having the first oxide semiconductor film includes a channel formation region of the first transistor, the channel formation region has a region overlapping the second insulating film and the third insulating film, the second oxide semiconductor film has a first region that overlaps with the second conductive film without the second insulating film and through the third insulating film; the first region has a region overlapping the first conductive film via the first insulating film, the first region functions as one electrode of the capacitor element; the first conductive film and the second conductive film are electrically connected to each other and function as the other electrode of the capacitance element; Semiconductor device.

5. In any one of claims 1 to 4, In a cross-sectional view of the first transistor in a channel length direction, a width of the second oxide semiconductor film is larger than a width of the first oxide semiconductor film. Semiconductor device.

6. In any one of claims 1 to 5, the first oxide semiconductor film and the second oxide semiconductor film are separated from each other. Semiconductor device.

Images