Light-emitting device

Abstract

To provide a display device with a high numerical aperture and including a capacitive element capable of increasing a capacitance value.SOLUTION: A pair of electrodes included in a capacitive element is composed of a translucent conductive film. One of the electrodes of the capacitive element is composed of a metal oxide film while the other electrode is composed of a translucent conductive film. This configuration allows light to be emitted to be emitted toward the capacitive element when an organic insulation film is provided on the capacitive element, a pixel electrode composing the light-emitting element is formed on the organic insulation film. Therefore, as the capacitive element can transmit light therethrough and be provided while overlapped with the light-emitting element, a numerical aperture can be improved and a capacitance value is increased.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine, relating to the manufacture or composition of matter, especially The present invention relates to, for example, a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, and In particular, the present invention relates to a driving method and a manufacturing method thereof. The present invention relates to a semiconductor device, a display device, and a driving method thereof. [Background technology]

[0002] It is used in many flat panel displays, such as liquid crystal displays and light-emitting displays. The transistors used are made of amorphous silicon and single-crystal silicon formed on a glass substrate. It is made of a silicon semiconductor such as silicon or polycrystalline silicon. Transistors using silicon semiconductors are also used in integrated circuits (ICs).

[0003] In recent years, metal oxides that exhibit semiconducting properties have been used in transistors instead of silicon semiconductors. In this specification, metal oxides that exhibit semiconducting properties are referred to as oxide semiconductors. Let us call it a conductor.

[0004] For example, a transistor using zinc oxide or an In-Ga-Zn oxide as an oxide semiconductor is used. A technique for manufacturing a transistor and using the transistor as a switching element for a pixel of a display device. Techniques for this have been disclosed (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 Summary of the Invention [Problem to be solved by the invention]

[0006] To improve the quality of display devices, it is necessary to improve the quality of the display itself (display quality) and power consumption. It is effective to try to reduce this.

[0007] In a transistor including an oxide semiconductor film, the transistor There is a problem that the electrical characteristics of the transistor, typically the threshold voltage, fluctuates. If a transistor has normally-on characteristics, malfunctions will occur during operation, and for example, This causes various problems, such as an increase in power consumption in the display device and a decrease in contrast in the display device. Therefore, improvement in display quality cannot be achieved.

[0008] In order to reduce power consumption, it is effective to improve the aperture ratio. It is effective to miniaturize the element and increase the area of ​​the opening. The smaller the capacitance value of the element, the less charge can be retained, resulting in a decrease in display quality. Therefore, there is a limit to how much the aperture ratio can be improved by reducing the capacitance value.

[0009] In view of this, one embodiment of the present invention provides a display device with excellent display quality. The display device has a high aperture ratio and a capacitance element capable of increasing the capacitance value. Another embodiment of the present invention provides a display device with reduced power consumption. Another embodiment of the present invention provides a display device including a transistor with excellent electrical characteristics. Another aspect of the present invention provides a novel display device. To provide a method for manufacturing a display device that has a high aperture ratio and a wide viewing angle with a small number of steps. Another embodiment of the present invention provides a method for manufacturing a novel display device.

[0010] The description of these problems does not preclude the existence of other problems. It is not necessary for the present invention to solve all of these problems. The above will be made clear from the description, 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 embodiment of the present invention is a transistor including an oxide semiconductor film, a first electrode, and a second electrode. a capacitor element having the inorganic insulating film provided on the transistor; a light-emitting element formed on the organic insulating film provided thereon, and the first electrode is formed on the inorganic insulating film The second electrode is a metal oxide film provided in contact with the inorganic insulating film. The pixel electrode of the light emitting element is a first conductive film having a light-transmitting property, and the pixel electrode of the light emitting element is a second conductive film having a light-transmitting property. and a transistor is formed in an opening provided in the inorganic insulating film and the organic insulating film. The display devices are electrically connected. [Effects of the Invention]

[0012] According to one embodiment of the present invention, a display device with excellent display quality can be provided. According to one aspect of the present invention, there is provided a capacitor element having a high aperture ratio and capable of increasing the capacitance value. According to one embodiment of the present invention, a display device having reduced power consumption can be provided. According to one embodiment of the present invention, a display device having excellent electrical characteristics can be provided. According to one embodiment of the present invention, a display device having a light-emitting diode (LED) and a display device having a light-emitting diode (LED) can be provided. A display device with a high aperture ratio and a wide viewing angle can be manufactured with a small number of steps. According to one embodiment of the present invention, a novel display device can be provided.

[0013] The description of these effects does not preclude the existence of other effects. The embodiment does not necessarily have to have all of these effects. , the specification, drawings, claims, etc., and It is possible to extract other effects from the claims and other descriptions. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 2] 1A and 1B are a block diagram and a circuit diagram illustrating one embodiment of a semiconductor device. [Figure 3] FIG. 1 is a top view illustrating one embodiment of a semiconductor device. [Figure 4] 1A and 1B are a circuit diagram and a timing chart illustrating one embodiment of a semiconductor device. [Figure 5] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 6] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 7] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 8] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 9] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 10] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 11] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 12] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 13] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 14] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 15] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 16] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 17] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 18] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 19] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 20] Cross-sectional TEM image and local Fourier transform image of an oxide semiconductor. [Figure 21] 1A and 1B are diagrams showing nanobeam electron diffraction patterns of an oxide semiconductor film and an example of a transmission electron diffraction measurement apparatus; [Figure 22] An example of structural analysis using transmission electron diffraction measurements, and a planar TEM image. [Figure 23] FIG. 1 is a conceptual diagram illustrating an example of a method for driving a display device. [Figure 24] FIG. 2 is a block diagram showing an example of the configuration of a pixel. [Figure 25] FIG. 2 is a diagram illustrating a display module. [Figure 26] 1A and 1B are diagrams illustrating external views of an electronic device according to an embodiment. [Figure 27] 1A and 1B are diagrams illustrating external views of an electronic device according to an embodiment. [Figure 28]FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 29] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 30] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 31] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 32] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 33] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 34] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 35] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 36] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 37] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 38] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 39] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 40] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 41] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 42] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 43] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 44] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 45] FIG. 10 is a diagram illustrating the temperature dependence of resistivity. [Figure 46] Schematic diagram illustrating a film formation model of CAAC-OS, and cross-sectional views of a pellet and CAAC-OS. [Figure 47] Schematic diagram explaining the film formation model of nc-OS and a diagram showing the pellet. [Figure 48] FIG. [Figure 49] 10A and 10B are diagrams illustrating the force applied to a pellet on a surface to be formed. [Figure 50] 10A and 10B are diagrams illustrating the movement of pellets on a surface to be formed. [Figure 51] A diagram explaining the InGaZnO4 crystal. [Figure 52] A diagram explaining the structure of InGaZnO4 before the atoms collide. [Figure 53] A diagram explaining the structure of InGaZnO4 after the atoms collide. [Figure 54] A diagram explaining the trajectories of atoms after they collide. [Figure 55] Cross-sectional HAADF-STEM images of the CAAC-OS and target. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments will be described with reference to the drawings. It is possible to carry out the invention in various forms and in various ways without departing from the spirit and scope of the invention. It will be readily apparent to those skilled in the art that various modifications may be made to the design and details of the present invention. The present invention is not limited to the following description of the embodiments. In the structure of the invention, reference numerals indicating the same objects are common among different drawings.

[0016] In addition, in the drawings, the size, thickness of layers, or areas may be exaggerated for clarity. Therefore, the drawings are not necessarily limited to the scale. The above is a formula and is not limited to the shapes or values ​​shown in the drawings. Variations in signals, voltages, or currents due to timing differences, or variations in signals, voltages, Alternatively, it is possible to include variations in current.

[0017] In this specification and the like, a transistor refers to a transistor having a gate (gate terminal or gate electrode) and It is an element having at least three terminals including a drain and a source. The drain (drain terminal, drain region or drain electrode) and the source (source terminal, source region The drain, the channel region, and the source electrode are connected to each other. It is possible to pass a current through it.

[0018] Here, the source and drain vary depending on the structure or operating conditions of the transistor. Therefore, it is difficult to determine which is the source and which is the drain. The part that functions as a source and the part that functions as a drain are not called source or drain. One of the source and drain is referred to as the first terminal, and the other is referred to as the second terminal. It may be written.

[0019] In this specification, the ordinal numbers "first," "second," and "third" are used to avoid confusion of the elements. It should be noted that the numbers are added to avoid confusion and are not intended to be limiting.

[0020] In this specification, "A and B are connected" does not mean that A and B are directly connected. In addition to those that are electrically connected, A and B are also included. Connected to means that there is an object that has some electrical effect between A and B. When this occurs, it refers to something that enables the transmission and reception of electrical signals between A and B.

[0021] In this specification, the terms "above" and "below" that indicate placement refer to the positional relationship between components. The relationship between the components is used for convenience in the description with reference to the drawings. The terms used in the specification may be changed depending on the direction in which each component is depicted. It is not limited to phrases, but can be rephrased appropriately depending on the situation.

[0022] The layout of each circuit block in the drawings is for the purpose of explanation only. Although the diagram shows different circuit blocks realizing different functions, the actual circuits and areas In some cases, different functions may be realized within the same circuit or the same area. The functions of each circuit block in the drawings are specified for the purpose of explanation, and Even if it is shown as one circuit block, in the actual circuit or area, it may be performed in one circuit block. In some cases, multiple circuit blocks are provided to perform this processing.

[0023] Voltage refers to the potential difference between a certain potential and a reference potential (for example, ground potential). Therefore, voltage, potential, and potential difference can be rephrased as potential, voltage, and voltage difference, respectively. Voltage refers to the potential difference between two points, and potential refers to the potential at a certain point. The electrostatic energy (electrical potential energy) of a unit charge in an electrostatic field This is what is meant.

[0024] Generally, potentials and voltages are relative. Therefore, the ground potential is It is not necessarily limited to 0 volts.

[0025] 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°. "Straight" refers to a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. This also includes cases where the angle is between 85° and 95°.

[0026] In this specification, when the crystal is a trigonal or rhombohedral crystal, it is expressed as a hexagonal crystal system. .

[0027] (Embodiment 1) In this embodiment, a semiconductor device which is one embodiment of the present invention will be described with reference to drawings.

[0028] FIG. 1A shows a cross-sectional view of a transistor 103 and a capacitor 105 included in a semiconductor device. vinegar.

[0029] The transistor 103 shown in FIG. 1A functions as a gate electrode provided over a substrate 302. and a gate insulating film 5 formed on the substrate 302 and the conductive film 304c. 1, an oxide semiconductor film 308b overlapping with the conductive film 304c with the gate insulating film 51 interposed therebetween, A pair of conductive films which function as a source electrode and a drain electrode and are in contact with the oxide semiconductor film 308b The conductive film 310d has a conductive film 310e.

[0030] Furthermore, a metal oxide film 308c is provided on the gate insulating film 51. The film 308c is connected to a conductive film 310f provided in the same layer as the conductive films 310d and 310e. In addition, an inorganic insulating film 53 is provided on the transistor 103 and the metal oxide film 308c. A conductive film 316b is provided on the inorganic insulating film 53. The insulating film 53 and the conductive film 316b form the capacitor element 105.

[0031] In addition, an organic insulating film 317 is provided on the inorganic insulating film 53 and the conductive film 316b. In the openings provided in the inorganic insulating film 53 and the organic insulating film 317, the conductive film 310e and A connecting conductive film 319 is provided on the organic insulating film 317. The conductive film 319 is The pixel electrode 394 functions as a pixel electrode (first electrode).

[0032] An insulating layer 391 is provided on the organic insulating film 317 and the conductive film 319. The light emitting layer 392 and the conductive layer 393 of the light emitting element 394 are formed in the opening provided in the edge layer 391. A conductive film 393 is provided over the conductive film 319. The conductive film 393 is a common film included in the light-emitting element 394. It functions as a conducting electrode (second electrode).

[0033] The metal oxide film 308c is an oxide semiconductor film formed at the same time as the oxide semiconductor film 308b. , hydrogen, boron, phosphorus, nitrogen, tin, antimony, rare gas elements, alkali metals, alkali By adding impurities such as earth metals and creating oxygen deficiencies, the conductivity is improved. Note that since the oxide semiconductor film has a light-transmitting property, the metal oxide film 308c It has translucency.

[0034] In an oxide semiconductor with oxygen vacancies, hydrogen enters the oxygen vacancy sites, and the conduction band As a result, the oxide semiconductor becomes more conductive and becomes a conductor. An oxide semiconductor that has been made into a conductor is called a metal oxide film, but it is also sometimes called an oxide conductor. Generally, oxide semiconductors have a large energy gap and are therefore transparent to visible light. On the other hand, an oxide conductor is an oxide semiconductor that has a donor level near the conduction band. Therefore, the influence of absorption due to the donor level is small, and the oxide semiconductor It has the same degree of translucency as

[0035] However, one aspect of the embodiment of the present invention is not limited to this. The oxide semiconductor film 308b may be formed in a separate process and then processed. Therefore, the metal oxide film 308c contains a material different from that of the oxide semiconductor film 308b. Furthermore, the metal oxide film 308c may be made of a material other than an oxide. For example, a film made of a metal element may be used, or a film partially containing nitrogen may be used. Furthermore, the metal oxide film 308c has a function of reflecting light emitted from the light emitting element. Good too.

[0036] The conductive film 316b and the conductive film 319 are formed using a light-transmitting conductive film. Therefore, the area of ​​the capacitor in the pixel is increased. It is possible to increase the capacitance value of the capacitive element and the aperture ratio of the pixel. When the conductive film 319 is used as the anode of the light-emitting element 394, the conductive film 319 is made of indium. A film having a work function higher than that of the light-emitting layer 392, such as tin oxide, and having light-transmitting properties may be used.

[0037] The inorganic insulating film 53 includes at least an oxide insulating film, and further includes an oxide insulating film and a nitride insulating film. In the inorganic insulating film 53, the oxide semiconductor film 308 is preferably laminated. The oxide insulating film is formed in the region in contact with the oxide semiconductor film 308b. The amount of defects at the interface with the inorganic insulating film 53 can be reduced.

[0038] The nitride insulating film also functions as a barrier film against water, hydrogen, and the like. When water, hydrogen, or the like is contained in the oxide semiconductor film 308b, the water, hydrogen, or the like is mixed with oxygen contained in the oxide semiconductor film 308b. The reaction occurs, and oxygen vacancies are formed in the oxide semiconductor film 308b. carriers are generated, the threshold voltage of the transistor shifts negatively, and the Therefore, by providing a nitride insulating film on the inorganic insulating film 53, The amount of diffusion of water, hydrogen, and the like from the oxide semiconductor film 308b to the oxide semiconductor film 308b can be reduced. Therefore, the amount of defects in the inorganic insulating film 53 can be reduced. an oxide insulating film and a nitride insulating film are stacked in this order from the oxide semiconductor film 308b side. As a result, the number of defects at the interface between the oxide semiconductor film 308b and the inorganic insulating film 53 and the amount of oxygen It is possible to reduce the amount of oxygen vacancies in the oxide semiconductor film 308b, and the normally-off It is possible to fabricate transistors with the following characteristics.

[0039] The organic insulating film 317 is made of organic resin such as acrylic resin, polyimide resin, or epoxy resin. The thickness of the organic insulating film 317 is 500 nm or more and 5000 nm or less. nm or less, preferably 1000 nm or more and 3000 nm or less.

[0040] In addition, the conductive film 319 formed on the organic insulating film 317 is connected to the transistor 103. The conductive film 319 functions as a pixel electrode of the light-emitting element 394 and The conductive film 317 is connected to the transistor 103 through an opening formed in the organic insulating film 317. 19 is far from the transistor 103, so the conductive film 3 of the transistor 103 As a result, the conductive film 319 overlaps with the transistor 103. It is possible to do this.

[0041] The insulating layer 391 has a function of separating the light emitting elements 394 between adjacent pixels, that is, as a partition wall. The insulating layer 391 may be made of, for example, an organic insulating material as long as it has insulating properties. As the organic insulating film, for example, a polyimide-based film or an inorganic insulating film can be used. Resin, polyamide resin, acrylic resin, siloxane resin, epoxy resin, or Phenol-based resins and the like can be used. Silicon oxide, oxynitride, etc. can be used as the inorganic insulating film. In particular, by using a photosensitive organic resin material, This is preferable because the layer 391 can be easily fabricated.

[0042] When the conductive film 393 is used as a cathode of the light-emitting element 394, the conductive film 393 is It is preferable to form the layer using a material with a small work function that can inject electrons into the layer. Instead of a metal with a low work function, an alkali metal or alkaline earth metal with a low work function is used. A layer of metal with a few nanometers of thickness is formed as a buffer layer, and then metal materials such as aluminum and iron are applied on top of it. It may be formed using a conductive oxide material such as indium tin oxide or a semiconductor material. The buffer layer may be made of an oxide, halide, or magnesium of an alkaline earth metal. An alloy such as sodium-silver can also be used.

[0043] The light-emitting layer 392 of the light-emitting element 394 is formed of a light-emitting layer containing at least a light-emitting substance. In addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron The light-emitting layer 392 may include a pair of functional layers, such as an injection layer and a charge generation layer. Electrons and holes are injected from the electrodes (here, the conductive film 319 and the conductive film 393), causing a current to flow. Then, the electrons and holes are recombined to form an excited state in the luminescent material, and can emit light when the excited state returns to the ground state.

[0044] Here, as a comparative example, a transistor in which the organic insulating film 317 is not formed on the inorganic insulating film 53 is used. In the semiconductor device having the transistor 103, a conductive film that functions as a gate electrode of the transistor 103 is The case where a negative voltage is applied to the conductive film 304c will be described.

[0045] When a negative voltage is applied to the conductive film 304c functioning as a gate electrode, an electric field is generated. The electric field is not blocked by the oxide semiconductor film 308b and affects the inorganic insulating film 53. A weak positive charge is applied to the surface of the inorganic insulating film 53. In addition, a conductive film that functions as a gate electrode When a negative voltage is applied to the film 304c, positively charged particles contained in the air are transported to the inorganic insulating film 53 The surface of the inorganic insulating film 53 is then charged with a weak positive charge.

[0046] Positive charges are applied to the surface of the inorganic insulating film 53, generating an electric field, which is then applied to the oxide semiconductor. This affects the interface between the conductive film 308b and the inorganic insulating film 53. As a result, the oxide semiconductor film 30 At the interface between the insulating film 8b and the inorganic insulating film 53, a positive bias is applied substantially. , the threshold voltage of the transistor shifts negatively.

[0047] On the other hand, the transistor 103 shown in FIG. 1A and described in this embodiment has a The organic insulating film 317 is thick, so that the conductive film 317 functions as a gate electrode. The influence of the electric field generated by applying a negative voltage to the organic insulating film 304c is 7, and the surface of the organic insulating film 317 is less likely to be positively charged. Even if positively charged particles contained in the air are adsorbed on the surface of the organic insulating film 317, the organic insulating film 31 Since the organic insulating film 317 is thick, the electric field of the positively charged particles adsorbed on the surface of the oxide semiconductor The oxide semiconductor film 308b and the inorganic insulating film 53 are hardly affected. At the interface between 308b and the inorganic insulating film 53, a state in which a positive bias is substantially applied is achieved. Therefore, the threshold voltage of the transistor varies little.

[0048] In addition, water and the like are easily diffused in the organic insulating film 317, but the inorganic insulating film 53 is a nitride insulating film. By having the film, the nitride insulating film acts as a barrier film for water, and the water diffused into the organic insulating film 317 This can prevent diffusion of the oxide semiconductor film 308b.

[0049] From the above, by providing the organic insulating film 317 on the transistor, the electric potential of the transistor can be reduced. It is possible to reduce variations in electrical characteristics. It also has normally-off characteristics and is highly reliable. In addition, the organic insulating film can be formed by a printing method, a coating method, etc. Since the film can be formed using a metal film, the manufacturing time can be reduced.

[0050] <About oxide conductors (metal oxide films)> Here, a film formed of an oxide semiconductor (hereinafter referred to as an oxide semiconductor film (OS)) and an oxide semiconductor film (OS) are In each of the films formed by oxide conductors (hereinafter referred to as oxide conductor films (OC)), The temperature dependence of resistivity will be explained using FIG. 45. In FIG. 45, the horizontal axis represents the measured The vertical axis shows the temperature, and the vertical axis shows the resistivity. The measurement results of the oxide semiconductor film (OS) are shown by circles. The measurement results for the oxide conductor film (OC) are indicated by square marks.

[0051] The sample including the oxide semiconductor film (OS) was prepared by depositing an oxide semiconductor film having an atomic ratio of In:Ga: The thickness was determined by sputtering using a sputtering target of Zn=1:1:1.2. A 35 nm In-Ga-Zn oxide film was formed with an atomic ratio of In:Ga:Zn=1:4: 5 sputtering target was used to deposit a 20 nm thick In-G After forming a α-Zn oxide film and heat-treating it in a nitrogen atmosphere at 450°C, The silicon nitride film is then formed by plasma CVD. Formed and produced.

[0052] The sample containing the oxide conductor (OC) film was prepared by depositing an oxide film with an atomic ratio of In:Ga: A 10 mm thick film was deposited by sputtering using a Zn=1:1:1 sputtering target. After forming a 0 nm In-Ga-Zn oxide film and heat-treating it in a nitrogen atmosphere at 450°C, Heat treatment was carried out in a mixed gas atmosphere of nitrogen and oxygen at 450°C, and silicon nitride was formed by plasma CVD. It was fabricated by forming a silicon film.

[0053] As can be seen from FIG. 45, the temperature dependence of resistivity in the oxide conductor film (OC) is The temperature dependence of resistivity is smaller than that of the oxide semiconductor film (OS). The change rate of the resistivity of the oxide semiconductor film (OC) at 90K or less is less than ±20%. Alternatively, the rate of change in resistivity between 150K and 250K is less than ±10%. That is, an oxide conductor is a degenerate semiconductor, and the conduction band edge and the Fermi level coincide or almost coincide. Therefore, when oxide conductor films are used for wiring, electrodes, pixel electrodes, etc. It is possible.

[0054] <Variation 1> A modified example of the configuration shown in FIG. 1(A) will be described with reference to FIG. 1(B). The semiconductor device is formed by using the conductive film 319 to form the conductive film 310e of the transistor 103 and the conductive film 3 16b are connected to each other.

[0055] The conductive film 319 is used as a wiring for connecting the conductive films in addition to functioning as a pixel electrode. As a result, the transistor 103 is connected to the capacitor 1 without any other wiring or transistor. 05 can be connected.

[0056] <Variation 2> A modified example of the configuration shown in FIG. 1(A) will be described with reference to FIG. 1(C). In the semiconductor device, the conductive film 310e of the transistor 103 and the metal oxide film 308c are directly connected to each other. The feature is that it is provided so as to be in contact with the surface.

[0057] By providing the conductive film 310e and the conductive film 316b so that they are in direct contact with each other, another wiring or a The capacitor 105 can be connected to the transistor 103 without an intervening transistor. do.

[0058] <Variation 3> A modification of the transistor described in this embodiment 1 will be described with reference to FIG. The transistor 103c shown in this modification is formed by a multi-tone mask (half-tone mask, a pair of oxide semiconductor films 308e formed using a mask such as a thin film mask or a phase difference mask; The transistor 103c and the conductive film 310f and the conductive film 310g are also included. The capacitor element 105 is connected to a conductive film 319 that functions as a pixel electrode. do.

[0059] By using a multi-tone mask, it is possible to form resist masks with multiple thicknesses. After the oxide semiconductor film 308e is formed using the resist mask, oxygen plasma By exposing the resist mask to light, a part of the resist mask is removed, forming a pair of conductive films. Therefore, the oxide semiconductor film 308e and the pair of conductive films 308c serve as a resist mask for forming the oxide semiconductor film 308e. The number of photolithography steps in the process of manufacturing the films 310f and 310g can be reduced. Cut.

[0060] Note that the oxide semiconductor film 308e formed using the multi-tone mask has a pair of planar shapes. The conductive films 310f and 310g are partially exposed to the outside.

[0061] In addition, in FIG. 29(A), a metal oxide film 308f is formed on the gate insulating film 51. In addition, the conductive film 310h is formed on the metal oxide film 308f at the same time as the conductive films 310f and 310g. In addition, the conductive film 319 is connected to the conductive film 310g and the conductive film 310h. As a result, the transistor 103 and the capacitor 105 are electrically connected to each other.

[0062] <Variation 4> A modification of the transistor described in this embodiment will be described with reference to FIG. The transistor 103d shown in the modification is a transistor formed with a channel protection structure. It is characterized by the following.

[0063] The transistor 103d with the channel protection structure has an opening in the insulating film 53a. The oxide semiconductor film 308b and the pair of conductive films 310i and 310j are connected to each other. With this shape, damage to the oxide semiconductor film 308b can be reduced.

[0064] <Variation 5> Modifications of the configuration shown in FIGS. 1A to 1C will be explained with reference to FIGS. 30A to 30C. The semiconductor device shown in FIGS. 30A to 30C includes a capacitor 105 and a light-emitting element 39. 4, a conductive film 304d formed in the same layer as the conductive film 304c is provided. It is a sign.

[0065] By providing the conductive film 304d so as to overlap with the metal oxide film 308c included in the capacitor 105, The metal oxide film 308c, the gate insulating film 51, and the conductive film 304d constitute a capacitance element. The capacitance value of the capacitive element 105 can be further increased.

[0066] <Variation 6> A modified example of the configuration shown in FIG. 29(B) will be described with reference to FIG. 43(A). The semiconductor device shown in FIG. 29(B) does not include the conductive film 316b provided in FIG. A conductive film 310k is provided in the same layer as the conductive film 310j and the conductive film 310i. The conductive film 310k is, for example, a conductive film 310j. 310i and the like are formed and etched at the same time. The conductive film 310k has, for example, the same material as the conductive film 310j.

[0067] This modification may be combined with the configuration shown in the above modification 5. As shown in FIG. 1B, the conductive film 304 is formed in a region overlapping the capacitor 105 and the light-emitting element 394. A conductive layer 304d formed in the same layer as the conductive film 304c can be provided. For example, the conductive film 304c is formed by being simultaneously deposited and etched. Therefore, the conductive film 304d has the same material as the conductive film 304c, for example. By using the conductive film 304d, it can function as part of the capacitor 105. Therefore, the conductive film 304d is connected to one of the electrodes of the capacitor 105. It may be done.

[0068] <Variation 7> A modification of the configuration shown in FIG. 1(A) will be described with reference to FIG. 31(A). The semiconductor device shown in FIG. 1A includes the oxide semiconductor film 308b and the metal oxide film 308c. In this structure, the oxide semiconductor film 308b is provided so as to be in direct contact with the , which is formed to have one island shape, and the semiconductor layer of the transistor 103 and the capacitor 105 It can also function as one of the electrodes.

[0069] The oxide semiconductor film 308b and the metal oxide film 308c in FIG. 31(A), the flatness on the organic insulating film 317 and the inorganic insulating film 53 can be improved. Therefore, the yield in manufacturing the semiconductor device can be improved. do.

[0070] This modification may be combined with the configuration shown in the above modification 5. As shown in FIG. 1B, the conductive film 304 is formed in a region overlapping the capacitor 105 and the light-emitting element 394. A conductive layer 304d formed in the same layer as the conductive layer 304c can be provided.

[0071] In the structures shown in FIGS. 31A and 31B, the oxide semiconductor film 308b and the conductive film 31 When the conductive film 310d and the conductive film 310e are formed using a multi-tone mask, An oxide semiconductor film 308b is always disposed below the film 310e. An example of this is shown in FIG. 41(A), (B), and (B), but the same applies to other modified examples. When a multi-tone mask is not used, the conductive film 310d and the conductive film 31 There may be a region below Oe where the oxide semiconductor film 308b is not provided. In this case, for example, the cross-sectional configuration shown in FIGS. 44(A) and 44(B) is obtained.

[0072] This modification may also be combined with the configuration shown in the modification 3. Specifically, as shown in FIG. It should be set as shown.

[0073] <Variation 8> A modification of the configuration shown in FIG. 1(B) will be described with reference to FIG. 32(A). In the semiconductor device shown in FIG. 1, the conductive film 316b is formed in an opening in the inorganic insulating film 53, and the conductive film 310e and the conductive film 316b and the conductive film 319 are connected to each other through an opening provided in the organic insulating film 317. It is characterized by being provided so as to be in direct contact with the surface.

[0074] By adopting the structure of FIG. 32(A), the shape of the opening in the organic insulating film 317 and the inorganic insulating film 53 can be The same photomask can be used for the fabrication, which reduces the number of masks required.

[0075] This modification may be combined with the configuration shown in the above modification 5. As shown in FIG. 1B, the conductive film 304 is formed in a region overlapping the capacitor 105 and the light-emitting element 394. A conductive layer 304d formed in the same layer as the conductive layer 304c can be provided.

[0076] As shown in FIGS. 33(A) and (B), in the configuration shown in FIGS. 32(A) and (B), The openings in the organic insulating film 317 and the inorganic insulating film 53 are formed using different photomasks. The structure may be such that the insulating film is formed and provided as above.

[0077] <Variation 9> The conductive film described in the above-listed modified examples may be the gate insulating film 51, the organic insulating film 317, or are openings provided in the inorganic insulating film 53, and have the function of connecting the conductive films of the respective layers together. In this case, various conductive films are used to connect the pixel area, the driving circuit area, the protection circuit area, and the peripheral area. It can be provided as a connection terminal or a protection circuit in the area.

[0078] As an example, FIGS. 35A and 35B show a conductive film provided in the same layer as a gate electrode and a capacitor element. A conductive film provided as one electrode of 105 and a conductive film provided in the same layer as the pixel electrode are 10 is a cross-sectional configuration example of a connection via a

[0079] As an example, FIGS. 36(A) and 36(B) show a conductive layer provided in the same layer as the source electrode or drain electrode. The conductive film and the conductive film provided as one electrode of the capacitor element 105 are provided in the same layer as the pixel electrode. 10 is a cross-sectional configuration example of a connection via a conductive film.

[0080] As an example, FIGS. 37(A) and 37(B) show a conductive layer provided in the same layer as the source electrode or drain electrode. The cross-sectional structure directly connects the conductive film and the conductive film provided as one electrode of the capacitor element 105. This is a typical example.

[0081] As an example, FIGS. 38A and 38B show a conductive film provided in the same layer as a gate electrode and a capacitor element. This is an example of a cross-sectional configuration in which the conductive film 105 is directly connected to one of the electrodes.

[0082] As an example, FIGS. 39(A) and (B) show a conductive film provided in the same layer as the gate electrode and a source electrode. 10 is a cross-sectional configuration example in which a conductive film provided in the same layer as a lead or drain electrode is directly connected to the lead or drain electrode.

[0083] The cross-sectional configuration examples shown in FIGS. 35, 36, 37, 38, and 39 are pixel regions, drive circuits, and The present invention can be applied to various areas such as the protection circuit area, the peripheral area, etc. In the cross-sectional view, some films (conductive films, insulating films, semiconductor films, etc.) and substrates are omitted. There may be cases where this is the case.

[0084] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0085] (Embodiment 2) In this embodiment, a semiconductor device according to one embodiment of the present invention and a manufacturing method thereof will be described with reference to the drawings. This will be explained in light of the above.

[0086] FIG. 2A shows a display device as an example of a semiconductor device. The display device shown in FIG. The pixel section 11, the scanning line driving circuit 14, and the signal line driving circuit 16 are parallel or approximately parallel to each other. The scanning line driving circuit 14 controls the potential of m scanning lines (m is a natural number). The scanning lines 17 are arranged parallel or approximately parallel to each other, and are driven by a signal line driving circuit 16. and n signal lines 19 (n is a natural number) through which the pixel section 11 is controlled. The pixel array has a plurality of pixels 301 arranged in a pixel pattern. The capacitance lines 25 are arranged in rows or approximately parallel to the scanning lines 17. Therefore, they may be arranged parallel or approximately parallel to each other. The signal line driving circuit 16 may be collectively referred to as a driving circuit section.

[0087] The display device includes a driver circuit for driving a plurality of pixels. The control circuit, power supply circuit, signal generation circuit, backlight module, etc. are arranged on the board. It is sometimes called a display module.

[0088] 2B and 2C show a circuit that can be used for the pixel 301 of the display device shown in FIG. 2A. 1 shows an example of a road configuration.

[0089] A pixel 301 shown as an example in FIG. 2B includes a liquid crystal element 31, a transistor 103, and a capacitor. and a capacitance element 105.

[0090] In addition, a pixel 301 shown as an example in FIG. 2C includes a transistor 43 and a transistor 1. 03, a transistor 45, a capacitor 105, and a light-emitting element 41.

[0091] In addition, in FIG. 2(B) and FIG. 2(C), a liquid crystal element 31 and a light emitting element 41 are used as display elements. Although an example using various display elements has been described, one aspect of the embodiment of the present invention is not limited to this. For example, an EL (electroluminescence) element (organic and inorganic EL elements, organic EL elements, inorganic EL elements), LEDs (white LEDs, red LED, green LED, blue LED, etc.), transistor (transistor that emits light according to the current) Electron emission element, liquid crystal element, electronic ink, electrophoretic element, grating light bar GLV, Plasma Display Panel (PDP), MEMS (Micro-Electro-Mechanical Systems) Digital Micromirror Device (DMD), DMS ( Digital Micro Shutter), IMOD (Interference Modulation element, electrowetting element, piezoelectric ceramic display, carbon nano Tubes, etc., have changes in contrast, brightness, reflectivity, transmittance, etc. due to electromagnetic effects. An example of a display device using an EL element is an EL display. An example of a display device using electron-emitting elements is a field emitter. Surface-Mounted Display (FED) or Surface-Mounted Display (SED) ace-conduction Electron-emitter Display) An example of a display device using a liquid crystal element is a liquid crystal display (transmissive liquid crystal Displays, semi-transmissive LCD displays, reflective LCD displays, direct-view LCD displays Display using electronic ink or electrophoretic elements. An example of a display device is electronic paper.

[0092] Next, a specific configuration of the element substrate included in the display device will be described. A display device that displays by emitting light from an EL element is used as the device, and pixels pi included in the display device The top view of x is shown in Figure 3. The circuit configuration corresponding to the top view is shown in Figure 4(A). The timing chart of this is shown in FIG. 4(B). Cross-sectional views of the JK, LM, and NO sections are shown in FIG.

[0093] In FIG. 3, the conductive film 304c functioning as a scanning line is different from the conductive film functioning as a signal line. The conductive wires function as signal lines. The film 310d extends in a direction (vertical direction in the drawing) substantially perpendicular to the conductive film that functions as the scanning line. The conductive film 304c functioning as a scan line is provided in the scan line driver circuit 14. (See FIG. 2(A)). d is electrically connected to the signal line driving circuit 16 (see FIG. 2(A)).

[0094] In the top view shown in FIG. 3, transistors M1 to M6 included in the pixel pix are 3 shows an example of the arrangement of the capacitor element C1 and the light-emitting element EL. 1 shows an example of the arrangement of wirings L1 to GL3, wiring SL, wiring VL1, wiring VL0, and wiring IL. The wirings GL1 to GL3, the wiring SL, the wiring VL1, the wiring VL0, and the wiring IL are The electrodes are connected to the gates, sources, or drains of the transistors M1 to M6. The connection relationship between each wiring and each transistor is shown in the circuit configuration in FIG. Please refer to the following.

[0095] By configuring a pair of electrodes constituting the capacitance element C1 with a pair of transparent conductive films, Therefore, the capacitance element C1 can be provided in the pixel pix so as to overlap with the light-emitting element EL. Even if it is formed large (in a large area), the aperture ratio will not decrease. However, it is possible to make it typically 50% or more, preferably 60% or more, and For example, a display device with increased resolution, e.g. In a liquid crystal display device, the area of ​​a pixel is reduced, and the area of ​​a capacitance element is also reduced. Therefore, in a display device with high resolution, the amount of capacitance stored in the capacitive element is small. However, since the capacitor C1 shown in this embodiment has a light-transmitting property, the capacitor C1 is By providing the capacitor 10 at this position, it is possible to obtain a sufficient capacitance value in each pixel and increase the aperture ratio. Typically, pixel densities are 100 ppi or higher, or even 200 ppi or higher, or even 300 ppi. The present invention can be suitably used in high-resolution display devices having a resolution of 1000 pi or more.

[0096] Next, the circuit configuration and operation corresponding to the top view of the pixel pix shown in FIG. 3 will be described.

[0097] 4A shows an example of a circuit diagram of the pixel pix. The pixel pix includes transistors M1 to M2. The transistor M6, the capacitance element C1, and the light-emitting element EL are included. 1. Transistors M3 to M6 only need to function as switches. It is possible to replace it with a switch.

[0098] The pixel electrode of the light-emitting element EL has a potential that changes in accordance with the image signal Sig input to the pixel pix. The brightness of the light-emitting element EL is determined by the potential difference between the pixel electrode and the common electrode. For example, when an OLED is used as a light-emitting element, either the anode or the cathode In FIG. 4A, one electrode functions as a pixel electrode, and the other electrode functions as a common electrode. The anode of the pixel pix is ​​used as a pixel electrode, and the cathode of the light-emitting element EL is used as a common electrode. 1 illustrates an example configuration.

[0099] The transistor M1 is a transistor for electrically connecting the wiring SL and one of the pair of electrodes of the capacitance element C1. The other of the pair of electrodes of the capacitor C1 is connected to a transistor The transistor M3 is connected to one of the source and drain of the wiring VL0 and the transistor M2. The transistor M4 has the function of controlling the conduction state between the gate of the transistor M2 and the gate of the transistor M3. The conduction state between one of the pair of electrodes of the capacitance element C1 and the gate of the transistor M2 is The transistor M5 has the function of controlling the source and drain of the transistor M2. The transistor has the function of controlling the conduction state between one of the electrodes and the anode of the light-emitting element EL. The transistor M6 is connected to one of the source and drain of the transistor M2 and the wiring VL1. It has the function of controlling the state.

[0100] Furthermore, in FIG. 4A, the other of the source and the drain of the transistor M2 is connected to the wiring IL. It continues.

[0101] The on / off selection of the transistor M1 is performed by applying a voltage to the gate of the transistor M1. The ON / OFF state of the transistor M3 is determined by the potential of the wiring GL1 to which the transistor M3 is connected. The selection of the transistor M3 is performed according to the potential of the wiring GL1 connected to the gate of the transistor M3. The on / off selection of transistor M4 is performed by connecting the gate of transistor M4 to The on / off state of the transistor M5 is determined according to the potential of the wiring GL2. The selection is made according to the potential of the wiring GL2 connected to the gate of the transistor M5. The on or off selection for transistor M6 is connected to the gate of transistor M6. This is done according to the potential of the wiring GL3.

[0102] The transistor included in the pixel pix may be made of an oxide semiconductor, an amorphous, microcrystalline, polycrystalline, or Single crystal semiconductors such as silicon or germanium can be used. The transistor M1, the transistor M3, and the transistor M4 contain an oxide semiconductor in the channel formation region. By doing so, the off-state current of the transistors M1, M3, and M4 can be minimized. The transistor M1 and the transistor M2 having the above configuration can be made smaller. By using M3 and transistor M4 in the pixel pix, ordinary silicon or germanium The transistors formed of semiconductors such as transistor M1, transistor M3, and transistor M4 are Compared to when using the transistor M4, the leakage of the charge stored in the gate of the transistor M2 is This can prevent problems.

[0103] Therefore, like a still image, the same image information is displayed on the pixel portion over several consecutive frame periods. When an image signal Sig having information is written, the driving frequency is lowered, in other words, Therefore, even if the number of times that the image signal Sig is written to the pixel section within a certain period is reduced, the image For example, the highly purified oxide semiconductor can be used as the transistor M 1. By using it for the semiconductor film of the transistor M3 and the transistor M4, the image signal Sig The interval between writing should be 1 second or more, preferably 3 seconds or more, and more preferably 10 seconds or more. The longer the interval at which the image signal Sig is written, the less power is consumed. Power consumption can be further reduced.

[0104] In addition, the potential of the image signal Sig can be maintained for a longer period of time, Even if the pixel pix does not have a capacitance element C1 for maintaining the potential of the gate of the transistor M2, Therefore, the capacitance element C1 is not provided. By reducing the size of the capacitance element C1, the aperture ratio of the pixel pix can be increased. This can increase the lifetime of the light-emitting element EL, and ultimately improve the reliability of the display device. It can increase reliability.

[0105] In FIG. 4A, the pixel pix may include a transistor, a diode, It may further include other circuit elements such as resistors, capacitors, and inductors.

[0106] In addition, in FIG. 4A, each transistor has a gate on at least one side of the semiconductor film. However, it is also possible to have a pair of gates sandwiching a semiconductor film therebetween. If one of the pair of gates is a back gate, it can be used in the same way as a normal gate and a back gate. A fixed potential such as a ground potential may be applied only to the back gate. By controlling the level of the potential applied to the back gate, The threshold voltage of the transistor can be controlled. The resulting increase in the drain current is also a significant advantage. This makes it easier for a depletion layer to form in the semiconductor film, which improves the S value. 4(A) shows, as an example, transistors M1 to M3 and transistor M6. The transistor is arranged so that the semiconductor film is surrounded by gate electrodes from above and below. In FIG. 4(A), it is shown with a symbol different from the other circuit symbols.

[0107] FIG. 4A shows an example in which all the transistors are n-channel transistors. If all the transistors in a pixel are of the same channel type, In this case, a process of adding an impurity element that gives one conductivity to the semiconductor film can be partially omitted. However, in the display device according to one embodiment of the present invention, the transistors in the pixels pix are not necessarily The cathode of the light-emitting element EL is connected to the wiring CL. In this case, it is desirable that at least the transistor M2 be an n-channel type. When the anode of the element EL is connected to the wiring CL, at least the transistor M2 is a p-channel It is preferable that the filter be of the flannel type.

[0108] In addition, in FIG. 4A, the transistor in the pixel pix has a single gate. Although the example shows a single gate structure having a single channel forming region, One embodiment of the present invention is not limited to this configuration. However, by having a plurality of electrically connected gates, it is possible to form a semiconductor device having a plurality of channel forming regions. It may have a multi-gate structure.

[0109] FIG. 4B shows the wiring GL1, wiring GL2, and wiring GL3 connected to the pixel pix shown in FIG. 4A. 10 is a timing chart showing the potential of GL3 and the potential of the image signal Sig supplied to the wiring SL. The timing chart shown in FIG. 4B is for the pixel pix shown in FIG. This is an example in which all the transistors included are n-channel type.

[0110] First, in a period t1, a low-level potential is applied to the wiring GL1, and a low-level potential is applied to the wiring GL2. A potential is applied, and a signal potential for switching from L level to H level is applied to the wiring GL3. Therefore, the transistor M5 is turned from on to off, and the transistors M1 and M2 are turned off. M3 and transistor M4 are turned off, and transistor M6 is turned on. When transistor M6 is turned on, one of the source and drain of transistor M2 and the capacitor The potential V0 of the wiring VL1 is applied to the other of the pair of electrodes of the capacitor C1.

[0111] The wiring IL is supplied with a potential Vano, and the wiring CL is supplied with a potential Vcat. The potential Vano is higher than the potential obtained by adding the threshold voltage Vthe of the light-emitting element EL to the potential V0. In addition, the potential V0 is preferably set to the threshold voltage Vth of the light-emitting element EL. It is desirable that the potential V0 is lower than the potential obtained by adding e. During the period t1, it is possible to prevent a current from flowing through the light-emitting element EL.

[0112] Next, in a period t2, an H-level potential is applied to the wiring GL1, and an L-level potential is applied to the wiring GL2. A potential of L level is applied to the wiring GL3. Transistor M1 and transistor M3 are turned on, and transistor M4, transistor M5 and transistor M6 are turned on. Transistor M6 is turned off.

[0113] When the period t1 is changed to the period t2, the potential applied to the wiring GL1 is changed from the L level to the H level. After switching to the high level, the potential applied to the wiring GL3 is switched from the high level to the low level. By performing such an operation, the potential applied to the wiring GL1 can be switched. By replacing one of the source and drain of the transistor M2 and the pair of capacitors C1, Fluctuations in the potential of the other of the electrodes can be prevented.

[0114] The wiring IL is supplied with a potential Vano, and the wiring CL is supplied with a potential Vcat. The line SL is supplied with a potential Vdata of the image signal Sig, and the line VL0 is supplied with a potential The potential V1 is the potential Vcat plus the threshold voltage Vth of the transistor M2. The potential Vano is higher than the calculated potential, and is the potential obtained by adding the threshold voltage Vth of the transistor M2 to the potential Vano. It is desirable that it is lower than the above.

[0115] In the pixel configuration shown in FIG. 4A, the potential V1 is set to the threshold voltage Vthe of the light-emitting element EL. Even if the potential Vcat is higher than the value added to the potential Vcat, as long as the transistor M5 is off, the light-emitting element Therefore, it is possible to widen the range of values ​​that can be set as the potential V0. This makes it possible to widen the range of values ​​that can be taken as V1-V0. The time required to obtain the threshold voltage of transistor M2 increases as the degree of freedom in setting the value of V0 increases. Even if the time is shortened or the acquisition period of the threshold voltage is limited, the The threshold voltage of the resistor M2 can be obtained.

[0116] By the above operation, the potential V1 is input to the gate of the transistor M2, and the transistor M2 Therefore, the charge in the capacitance element C1 is released through the transistor M2, and the potential V 0, one of the source and drain of the transistor M2 and the pair of potentials of the capacitance element C1 The potential of the other pole begins to rise, eventually reaching the source and The potential of one of the drains and the other of the pair of electrodes of the capacitance element C1 is V1-Vth. When the gate voltage of the transistor M2 converges to the threshold voltage Vth, the transistor M 2 will be turned off.

[0117] One of the pair of electrodes of the capacitance element C1 is connected to the image signal Si The potential Vdata of g is applied via a transistor M1.

[0118] Next, in a period t3, an L-level potential is applied to the wiring GL1, and an H-level potential is applied to the wiring GL2. A potential of L level is applied to the wiring GL3. Transistor M4 and transistor M5 are turned on, and transistor M1, transistor M3 and transistor M4 are turned on. Diaster M6 is turned off.

[0119] When the period t2 shifts to the period t3, the potential applied to the wiring GL1 changes from the H level to the L level. After the signal is switched to the bell, the potential applied to wire GL2 is switched from L level to H level. By performing such an operation, the potential applied to the wiring GL1 can be switched. By replacing one of the source and drain of the transistor M2 and the pair of capacitors C1, Fluctuations in the potential at the other of the electrodes can be prevented.

[0120] The wiring IL is supplied with a potential Vano, and the wiring CL is supplied with a potential Vcat.

[0121] By the above operation, the potential Vdata is applied to the gate of the transistor M2. The gate voltage of transistor M2 is Vdata-V1+Vth. The gate voltage can be set to a value that takes into account the threshold voltage Vth. This makes it possible to suppress variations in the threshold voltage Vth of the transistor M2. It is possible to suppress variations in the current value supplied to the light element EL, thereby reducing uneven brightness of the display device. It is possible.

[0122] By increasing the fluctuation of the potential applied to the wiring GL2, the threshold voltage of the transistor M5 It is possible to prevent voltage variations from affecting the current value supplied to the light-emitting element EL. In other words, the H level potential applied to the wiring GL2 is set to be sufficiently higher than the threshold voltage of the transistor M5. The L level potential applied to the wiring GL2 is set to a value greater than the threshold voltage of the transistor M5. By making it small enough, it can reliably switch transistor M5 on and off, Prevents variations in the threshold voltage of transistor M5 from affecting the current value of the light-emitting element EL. It is possible.

[0123] Next, in a period t4, an L-level potential is applied to the wiring GL1, and an L-level potential is applied to the wiring GL2. A potential of H level is applied to the wiring GL3. 6 is turned on, and transistors M1, M3, M4 and M5 are turned on. Sta M5 will be off.

[0124] A potential Vano is applied to the wiring IL, and the wiring VL1 is connected to the monitor circuit. .

[0125] By the above operation, the drain current Id of the transistor M2 flows through the transistor M1, not the light-emitting element EL. The monitor circuit detects the drain current flowing through the wiring VL1. The drain current Id is used to generate a signal containing the value of the drain current Id as information. The drain current Id depends on the mobility of the transistor M2 and the size of the transistor M2 (channel The size of the electrode depends on the channel length, channel width, etc. In the display device, the potential Vd of the image signal Vsig supplied to the pixel pix is ​​adjusted by using the signal. In other words, the mobility variation of the transistor M2 can be corrected. The impact can be reduced.

[0126] In the display device having the pixel pix shown in FIG. 4A, after the operation of the period t3, For example, in a display device, the operation of the period t1 to the period t3 is not always performed. The operation in the period t4 may be performed after repeating the operation several times. After the operation for the period t4 is performed in pix, the image signal corresponding to the minimum gradation value 0 is By writing to the pixel pix of the row that performed the operation, the light-emitting element EL is put into a non-emitting state. , the operation of the period t4 may be performed for the pixels pix in the next row.

[0127] In the display device having the pixel pix shown in FIG. 4A, the source and drain of the transistor M2 The other drain and the gate of transistor M2 are electrically isolated from each other. Therefore, in the period t2, the potential of the transistor M2 can be controlled individually. The potential of the other of the source and drain is set to the potential of the gate of the transistor M2, and the threshold voltage Vth Therefore, the transistor M2 can be set to a value higher than the potential obtained by adding When the gate is negative, that is, when the threshold voltage Vth has a negative value, In the transistor M2, the capacitance is increased until the source potential becomes higher than the gate potential V1. Therefore, in the display device according to one aspect of the present invention, Even if the transistor M2 is normally on, the threshold voltage is obtained during the period t2. In the period t3, the transistor The gate voltage of M2 can be set.

[0128] Next, a cross-sectional view of the dashed lines JK, LM, and NO in FIG. 3 is shown in FIG. .

[0129] The conductive film 304c functions as a gate electrode, and the insulating film 30 functions as a gate insulating film 51. 5, the insulating film 306, and the oxide film on which the channel region is formed formed on the gate insulating film 51. The semiconductor film 308b, the conductive films 310d and 310d functioning as a source electrode and a drain electrode, e constitutes the transistor 103 (corresponding to the transistor M5 in FIG. 3). On the conductive films 310d and 310e, insulating films 312 and 314, which are the inorganic insulating film 53, are formed. is provided as a protective film.

[0130] Also, a metal oxide film 308c which functions as one electrode and an insulating film which functions as a dielectric film 3, and the conductive film 316b serving as the other electrode forms the capacitor element 105 (see FIG. 3). The metal oxide film 308c is provided on the gate insulating film 51. The transistor M6 and the metal oxide film 308c are connected to the source electrode of the transistor M6 and The drain electrode is connected to the drain electrode by a conductive film 310f.

[0131] An organic insulating film 317 is formed on the inorganic insulating film 53. In addition, a pixel is formed on the organic insulating film 317. The conductive film 319 that functions as a base electrode is formed. An opening provided in the organic insulating film 317 connects to the conductive film 310e.

[0132] An insulating layer 391 is provided on the organic insulating film 317 and the conductive film 319. The light emitting layer 392 and the conductive layer 393 of the light emitting element 394 are formed in the opening provided in the edge layer 391. A film 393 is provided on the conductive film 319 .

[0133] 6, the driving circuit including the scanning line driving circuit 14 and the signal line driving circuit 16 shown in FIG. 2(A) is The cross-sectional view of the operating circuit section (top view omitted) is shown in AB, and the cross-sectional structure of the pixel shown in Fig. 5 is also shown. The information is shown on the CD.

[0134] In the driving circuit section, a conductive film 304a functioning as a gate electrode and a gate insulating film 51 are formed. the insulating film 305 and the insulating film 306 that function as a channel region; 08a, and the conductive films 310a and 310b functioning as source and drain electrodes. The oxide semiconductor film 308a forms the transistor 102. The oxide semiconductor film 308a is provided on the gate insulating film 51. In addition, an insulating film 312, which is an inorganic insulating film 53, and an insulating film 314 are formed on the conductive films 310a and 310b. A protective film 314 is provided.

[0135] In the driving circuit section, the conductive film 304 is formed simultaneously with the conductive films 304a and 304c. b and the conductive films 310a, 310b, 310d, 310e, and 310f formed at the same time. The conductive film 310c is connected to the conductive film 319a formed at the same time as the conductive film 319.

[0136] The conductive film 304b and the conductive film 319a are formed on the gate insulating film 51, the inorganic insulating film 53, and the organic insulating film 54. The conductive film 310c and the conductive film 319a are connected to each other through an opening formed in the conductive film 317. The insulating film 312, the insulating film 314, and the organic insulating film 317 are connected to each other through openings. To be continued.

[0137] The components of the display device shown in FIGS. 5 and 6 will now be described.

[0138] Conductive films 304a, 304b, and 304c are formed on the substrate 302. The conductive film 4a functions as a gate electrode of a transistor in the driving circuit section. The conductive film 304b is formed in the driving circuit section and is connected to the conductive film 310c. , which are formed in the pixel section 11 and function as gate electrodes of the transistors in the pixel section.

[0139] There is no particular restriction on the material of the substrate 302, but it should be strong enough to withstand the subsequent heat treatment. It must be heat resistant. For example, glass substrates, ceramic substrates, quartz substrates, and surface treatment substrates are A fiber substrate or the like may be used as the substrate 302. Also, silicon or silicon carbide may be used as the material. A single crystal semiconductor substrate, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, etc. It is also possible to apply a substrate, an SOI substrate, etc., on which a semiconductor element is provided. The substrate 302 may be a glass substrate. In this case, the 6th generation (1500mm x 1850mm) and 7th generation (1870mm x 2200 mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 2800 By using large area substrates such as 10th generation (2950mm x 3400mm), It is possible to fabricate a display device of this type.

[0140] In addition, a flexible substrate is used as the substrate 302, and a transistor is formed directly on the flexible substrate. Alternatively, a separation layer may be provided between the substrate 302 and the transistor. After completing a part or all of the element part on it, it is separated from the substrate 302 and mounted on another substrate. In this case, the transistors are mounted on substrates with poor heat resistance or flexible substrates. It can also be transferred to a circuit board.

[0141] The conductive films 304a, 304b, and 304c may be made of aluminum, chromium, copper, tantalum, A metal element selected from titanium, molybdenum, and tungsten, or a metal element containing the above-mentioned metal elements. The metal layer can be formed by using an alloy containing the metal elements or an alloy combining the above-mentioned metal elements. In addition, the present invention uses a metal element selected from one or more of manganese and zirconium. The conductive films 304a, 304b, and 304c may have a single layer structure or a laminate of two or more layers. For example, a single layer structure of an aluminum film containing silicon, an aluminum Two-layer structure with titanium film laminated on titanium nitride film, two-layer structure with titanium film laminated on titanium nitride film, Two-layer structure in which a tungsten film is laminated on a titanium nitride film, a tantalum nitride film or a tungsten nitride film Two-layer structure with tungsten film on titanium film, and aluminum film on titanium film. There are also three-layer structures, such as a laminated aluminum film and a titanium film on top of that. Titanium, tantalum, tungsten, molybdenum, chromium, neodymium, scandium An alloy film or a nitride film made by combining one or more elements selected from the group consisting of fluorine and fluorine may be used. stomach.

[0142] The conductive films 304a, 304b, and 304c are made of indium tin oxide or tungsten oxide. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide, titanium oxide, indium tin oxide, indium zinc oxide, By using a conductive material with light transmission such as indium tin oxide with added silicon oxide, Furthermore, it is possible to form a laminated structure of the above-mentioned light-transmitting conductive material and the above-mentioned metal element. It can also be done as follows.

[0143] An insulating film 305, an insulating film 306, and a conductive film 304a, 304b, and 304c are formed on the substrate 302 and the conductive films 304a, 304b, and 304c. The insulating film 305 and the insulating film 306 are formed on the gate of the transistor in the driving circuit section. and functions as the gate insulating film 51 of the transistor in the pixel section 11. do.

[0144] The insulating film 305 may be, for example, silicon nitride, silicon nitride oxide, aluminum nitride, or nitride. It is preferable to form the insulating film using a nitride such as aluminum oxide.

[0145] The insulating film 306 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. silicon oxide, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn based metals An oxide or the like may be used, and may be formed as a stacked layer or a single layer. HfSiO x ), nitrogen-doped hafnium silicate (HfS i x O y N z ), nitrogen-doped hafnium aluminate (HfAl x O y N z ),acid By using high-k materials such as hafnium oxide and yttrium oxide, Gate leakage can be reduced.

[0146] The total thickness of the insulating film 305 and the insulating film 306 is preferably 5 nm or more and 400 nm or less. Preferably, the thickness is between 10 nm and 300 nm, more preferably between 50 nm and 250 nm. good.

[0147] Oxide semiconductor films 308a and 308b and a metal oxide film 308c are formed over the insulating film 306. The oxide semiconductor film 308a is formed in a position overlapping with the conductive film 304a. The oxide semiconductor film 308b functions as a channel region of a transistor in the drive circuit portion. The conductive film 304c is formed in a position overlapping the conductive film 304c, and serves as a channel region of a transistor in a pixel portion. The metal oxide film 308c is connected to the conductive film 310f and functions as a capacitor element 105. The conductive film 310f functions as an electrode of a transistor other than the transistor 103. These serve as the source and drain electrodes in the capacitor.

[0148] The oxide semiconductor films 308a and 308b and the metal oxide film 308c are typically made of In- Ga oxide, In-Zn oxide, In-M-Zn oxide (M is Al, Ti, Ga, Y, Z) The oxide semiconductor films 308a and 308b are examples of the oxide semiconductor films 308a and 308b. The metal oxide film 308b and the metal oxide film 308c are light-transmitting.

[0149] Note that the oxide semiconductor films 308a and 308b and the metal oxide film 308c are In-M-Zn When it is an oxide, the atomic ratio of In to M, excluding Zn and O, is the sum of In and M. When In is 100 atomic %, In is 25 atomic % or more, and M is 75 atomic % or more. c%, more preferably In is 34 atomic % or more and M is less than 66 atomic %. It is full.

[0150] The oxide semiconductor films 308a and 308b and the metal oxide film 308c have an energy gap is 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. In addition, by using an oxide semiconductor with a wide energy gap, the off-state current of a transistor can be reduced. can be reduced.

[0151] The oxide semiconductor films 308a and 308b and the metal oxide film 308c have a thickness of 3 nm or more. 00 nm or less, preferably 3 nm or more and 100 nm or less, and more preferably 3 nm or more and 50 nm or less.

[0152] The oxide semiconductor films 308a and 308b and the metal oxide film 308c are made of In:Ga:Zn. In:Ga:Zn=1:1:1, In:Ga:Zn=1:1:1.2, or In with an atomic ratio of 3:1:2 The oxide semiconductor films 308a, 308b, and 308c can be formed of a Ga—Zn oxide. The atomic ratios of the metal oxide film 308c and the metal oxide film 308d are determined by adding the plasma of the atomic ratios mentioned above as an error. Includes a 20% fluctuation.

[0153] The oxide semiconductor films 308a and 308b and the metal oxide film 308c are, for example, non-crystalline. The non-single crystal structure may be, for example, a CAAC-OS (C Axis A ligated Crystalline Oxide Semiconductor), This includes polycrystalline structures, microcrystalline structures (described later), and amorphous structures. The amorphous structure has the highest density of defect states, while the CAAC-OS has the lowest density of defect states. The oxide semiconductor films 308a and 308b and the metal oxide film 308c have the same crystallinity. .

[0154] Note that the oxide semiconductor films 308a and 308b and the metal oxide film 308c have an amorphous structure. region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single crystal structure region The mixed film may be a film having two or more of the above. , microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single crystal structure region. There are cases where the layer structure has two or more of these regions.

[0155] The oxide semiconductor films 308a and 308b contain silicon or carbon, which is one of the Group 14 elements. When the oxide semiconductor films 308a and 308b contain oxygen vacancies, the oxide semiconductor films 308a and 308b become n-type. As a result, the concentrations of silicon and carbon in the oxide semiconductor films 308a and 308b (concentration obtained by secondary ion mass spectrometry) is 2 x 10 18 atoms / cm 3 below , preferably 2 x 10 17 atoms / cm 3 The following applies.

[0156] In addition, the oxide semiconductor films 308a and 308b were analyzed by secondary ion mass spectrometry. The concentration of alkali metals or alkaline earth metals in the solution is 1×10 18 atoms / cm 3 below , preferably 2 x 10 16 atoms / cm 3 The following are alkali metals and alkaline earth metals: When metalloids bond with oxide semiconductors, they can generate carriers, which can be used as the on-state Therefore, the current of the oxide semiconductor films 308a and 308b may increase. It is preferable to reduce the concentration of alkali metals or alkaline earth metals.

[0157] When nitrogen is contained in the oxide semiconductor films 308a and 308b, electrons serving as carriers This increases the carrier density and makes it easier to become n-type. A transistor using a semiconductor tends to be normally on. In the conductive film, it is preferable that nitrogen is reduced as much as possible. For example, The nitrogen concentration obtained by mass spectrometry is 5×10 18 atoms / cm 3 To do the following: is preferred.

[0158] The oxide semiconductor films 308a and 308b are formed using oxide semiconductor films with low carrier density. For example, the oxide semiconductor films 308a and 308b have a carrier density of 1×10 17 pcs / c m 3 Less than 1 × 10 15 pieces / cm 3 or less, more preferably 1 × 10 13 pieces / cm 3 Less than or equal to 1×10 11 pieces / cm 3 The following oxide semiconductor film is used.

[0159] In addition, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use an appropriate composition depending on the required properties (mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of the transistor, the carriers of the oxide semiconductor films 308a and 308b Density, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. It is preferable to use the above-mentioned method.

[0160] The oxide semiconductor films 308a and 308b are formed by insulating films such as the insulating film 306 and the insulating film 312. The material is capable of improving the interface characteristics with the body membrane, so oxidation The oxide semiconductor films 308a and 308b function as semiconductors. The transistor having 8b has excellent electrical characteristics.

[0161] Note that the oxide semiconductor films 308a and 308b have a low impurity concentration and a low density of defect states. By using a thin oxide semiconductor film, a transistor with excellent electrical characteristics can be manufactured. Here, the impurity concentration is low and the defect level density is low (there is little oxygen deficiency). ) is called high purity genuine or substantially high purity genuine. High purity genuine or substantially high purity Intrinsic oxide semiconductors have few carrier generation sources, so they can reduce the carrier density. Therefore, a transistor having a channel region in the oxide semiconductor film may be formed. The transistor has electrical characteristics in which the threshold voltage is negative (also called normally on). In addition, the amount of the oxide semiconductor that is highly purified intrinsic or substantially highly purified intrinsic may be small. The film has a low defect level density, which may result in a low trap level density. An intrinsic or substantially highly purified intrinsic oxide semiconductor film has a significantly small off-state current and The width of the panel is 1 x 10 6 Even in a device with a channel length of 10 μm, the source and drain electrodes When the voltage between the drain electrodes (drain voltage) is in the range of 1V to 10V, the off-state current is Below the measurement limit of the parameter analyzer, i.e., 1 × 10 -13 Get the trait A or below Therefore, a transistor in which a channel region is formed in the oxide semiconductor film can be In this case, the change in electrical characteristics is small, and the transistor may become highly reliable. The charges trapped in the trap levels of the semiconductor film take a long time to disappear, as if Therefore, oxide semiconductors with high trap state density can behave like fixed charges. A transistor in which a channel region is formed in a semiconductor film may have unstable electrical characteristics. The impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, and the like.

[0162] The metal oxide film 308c is an oxide film formed simultaneously with the oxide semiconductor films 308a and 308b. Therefore, the metal oxide film 308c is formed by processing the oxide semiconductor film 3 The oxide semiconductor films 308a and 308b contain the same metal elements. The film may have a similar or different crystal structure to 308b. The oxide semiconductor film formed simultaneously with the oxide semiconductor films 308a and 308b is not doped with impurities or oxides. By providing the element deficiency, the film becomes conductive and functions as an electrode of the capacitance element. The impurity contained in the oxide semiconductor film is hydrogen. Boron, phosphorus, tin, antimony, rare gas elements, alkali metals, alkaline earth metals Alternatively, the metal oxide film 308c may contain the oxide semiconductor film 308a, This film was formed at the same time as 308b, and oxygen vacancies were formed due to plasma damage, etc. Alternatively, the metal oxide film 308c is a film having enhanced conductivity. a, 308b, and contains impurities and is plasma damaged. Oxygen vacancies are formed by the above-mentioned factors, and the conductivity of the film is increased.

[0163] Therefore, the oxide semiconductor films 308a and 308b and the metal oxide film 308c are insulating films. 306, but have different impurity concentrations. The impurity concentration of the metal oxide film 308c is higher than that of the oxide semiconductor film 308b. The hydrogen concentration in the films 308a and 308b is 5×10 19 atoms / cm 3 Less than, good Preferably 5 x 10 18 atoms / cm 3 Less than 1 x 1018 atoms / c m 3 Less than or equal to 5 × 10 17 atoms / cm 3 Below, more preferably 1× 10 16 atoms / cm 3 The hydrogen concentration in the metal oxide film 308c is 8 x10 19 atoms / cm 3 or more, preferably 1 × 10 20 atoms / cm 3 That's all, More preferably 5 × 10 20 atoms / cm 3 The above is the case. The hydrogen concentration in the metal oxide film 308c is preferably twice as high as that in the metal oxide film 308a and 308b. is more than 10 times higher.

[0164] In addition, the oxide semiconductor film formed at the same time as the oxide semiconductor films 308a and 308b is The oxide semiconductor film can be damaged by exposure to oxygen, and oxygen vacancies can be formed. For example, a film is formed on an oxide semiconductor film by plasma CVD or sputtering. When the insulating film 31 is heated, the oxide semiconductor film is exposed to the plasma, and oxygen vacancies are generated. In the etching treatment for forming 2, the oxide semiconductor film is exposed to plasma. Alternatively, when the oxide semiconductor film is exposed to hydrogen, a rare gas, ammonia, oxygen, and the like, oxygen vacancies are generated. When exposed to a plasma of a gas mixture of oxygen and hydrogen, oxygen vacancies are generated. The conductivity of the metal oxide semiconductor film increases, and the film becomes conductive, and the metal oxide film 308c is formed. It works like this.

[0165] In other words, the metal oxide film 308c can be said to be formed using an oxide semiconductor film with high conductivity. It can also be said that the metal oxide film 308c is formed of a metal oxide film with high conductivity.

[0166] When a silicon nitride film is used as the insulating film 314, the silicon nitride film contains hydrogen. Therefore, hydrogen in the insulating film 314 is formed simultaneously with the oxide semiconductor films 308a and 308b. When hydrogen diffuses into the oxide semiconductor film, the hydrogen bonds with oxygen in the oxide semiconductor film and becomes a carrier. In addition, silicon nitride films are formed by plasma CVD or sputtering. When the oxide semiconductor film is formed by the plasma etching method, the oxide semiconductor film is exposed to plasma, and oxygen vacancies are generated. When hydrogen contained in the silicon nitride film enters the oxygen vacancies, electrons, which act as carriers, are generated. As a result, the oxide semiconductor film becomes highly conductive and becomes the metal oxide film 308c. .

[0167] The metal oxide film 308c has a lower resistivity than the oxide semiconductor films 308a and 308b. The resistivity of the oxide semiconductor film 308c is 1×10 -8 1×10 times more -1 It is preferably less than 1×10 -3 Ωcm or more 1 x10 4 Ωcm, and more preferably a resistivity of 1×10 -3 Ωcm or more 1×10 -1 It is preferable that the resistivity is less than Ωcm.

[0168] However, one aspect of the embodiment of the present invention is not limited to this. In some cases, it is possible that the insulating film 314 is not in contact with the insulating film 314 .

[0169] In addition, one aspect of the embodiment of the present invention is not limited to this, and the metal oxide film 308c may be Depending on the circumstances, the oxide semiconductor film 308a and the oxide semiconductor film 308b may be formed in different steps. In that case, the metal oxide film 308c is formed by the oxide semiconductor film 308a or For example, the metal oxide film 308c may be made of indium tin. It may be formed using indium zinc oxide (hereinafter referred to as ITO), or indium zinc oxide. good.

[0170] In the display device described in this embodiment, the capacitor has a light-transmitting property. Since the capacitor element can be provided so as to overlap with the capacitor 394, the area occupied by the capacitor element can be increased while The aperture ratio can be increased.

[0171] The conductive films 310a, 310b, 310c, 310d, 310e, and 310f are made of a conductive material. Aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum Elemental metals consisting of buten, silver, tantalum, or tungsten, or metals with these as the main components The alloy is used as a single layer or a laminated layer. For example, an aluminum film containing silicon is used. a single layer structure, a two-layer structure with a titanium film laminated on an aluminum film, and a titanium film on a tungsten film. a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film; A layer structure, a titanium film or a titanium nitride film, and an aluminum film overlaid on the titanium film or the titanium nitride film. An aluminum film or a copper film is laminated, and a titanium film or a titanium nitride film is further formed thereon. A three-layer structure consisting of a molybdenum film or molybdenum nitride film and a molybdenum film or molybdenum nitride film. An aluminum or copper film is layered on top of the molybdenum film, and then a molybdenum or There are three-layer structures in which indium oxide, tin oxide or molybdenum nitride are formed. Alternatively, a transparent conductive material containing zinc oxide may be used.

[0172] The insulating film 306, the oxide semiconductor films 308a and 308b, the metal oxide film 308c, and the conductive film On the layers 310a, 310b, 310c, 310d, 310e, and 310f, an inorganic insulating film 53 is formed. As the insulating film 312, an insulating film 314 is formed. As in the case of 6, a material capable of improving the interface characteristics with the oxide semiconductor film can be used. Preferably, the insulating film 312 can be formed using an oxide insulating film. is formed by laminating insulating films 312a and 312b.

[0173] The insulating film 312a is an oxide insulating film that transmits oxygen. When the insulating film 312b is formed, the oxide semiconductor films 308a and 308b and the metal It also functions as a film for reducing damage to the oxide film 308c.

[0174] The insulating film 312a has a thickness of 5 nm to 150 nm, preferably 5 nm to 50 Silicon oxide, silicon oxynitride, etc., having a thickness of 1 nm or less can be used. In the above, a silicon oxynitride film is a film whose composition contains more oxygen than nitrogen. A silicon nitride oxide film is a film whose composition contains more nitrogen than oxygen. Point.

[0175] The insulating film 312a is an oxide insulating film that contains nitrogen and has a defect. It is preferable that the amount of recession is small.

[0176] Typical examples of oxide insulating films that contain nitrogen and have few defects include silicon oxynitride films, Examples include an aluminum oxynitride film.

[0177] The oxide insulating film with few defects shows a high level of The first signal has a g value of 2.037 or more and 2.039 or less, and the second signal has a g value of 2.001 or more and 2. A second signal with a g value of 1.964 or greater and a third signal with a g value of 1.966 or less. The split width of the first signal and the second signal and the The split width of the first signal and the third signal is about 5 m in the X-band ESR measurement. T. The first signal has a g value of 2.037 or more and 2.039 or less, and the second signal has a g value of 2.0 A second signal between 01 and 2.003, and a g value between 1.964 and 1.966, The total spin density of a third signal is 1×10 18 spins / cm 3 is less than , typically 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 less than is.

[0178] In addition, in the ESR spectrum below 100K, the g value is between 2.037 and 2.039. The first signal, the second signal with a g value between 2.001 and 2.003, and the g value between 1. The third signal, between 964 and 1.966, is nitrogen oxides (NOx, where x is between 0 and 2). , preferably 1 or more and 2 or less). Representative examples of nitrogen oxides include: Nitric oxide, nitrogen dioxide, etc. That is, the first group with a g value of 2.037 or more and 2.039 or less signal, a second signal with a g-value between 2.001 and 2.003, and a g-value between 1.96 The smaller the sum of the spin densities of the third signals, which is between 4 and 1.966, the more oxide It can be said that the content of nitrogen oxides contained in the insulating film is low.

[0179] If the insulating film 312a contains a small amount of nitrogen oxides as described above, the insulating film 312a and the oxide It is possible to reduce carrier traps at the interface with the oxide semiconductor film. As a result, it is possible to reduce the shift in threshold voltage of a transistor included in a display device. This reduces fluctuations in the electrical characteristics of the transistor.

[0180] The insulating film 312a is formed by SIMS (Secondary Ion Mass Spectroscopy). The nitrogen concentration measured by ionospheric spectrometry is 6×10 20 atoms / cm 3 is As a result, nitrogen oxides are less likely to be generated in the insulating film 312a. The transport of carriers at the interface between the insulating film 312a and the oxide semiconductor films 308a and 308b It is possible to reduce the overlap of the transistors included in the display device. It is possible to reduce voltage shifts and reduce variations in the electrical characteristics of transistors. This can be done.

[0181] If the insulating film 312a contains nitrogen oxides and ammonia, the manufacturing process During the heat treatment process, nitrogen oxides and ammonia react with each other, and nitrogen oxides turn into nitrogen gas. As a result, the nitrogen concentration and nitrogen oxide content of the insulating film 312a are reduced. In addition, the insulating film 312a and the oxide semiconductor films 308a and 308b It is possible to reduce the trapping of carriers at the interface. It is possible to reduce the shift in the threshold voltage of the transistor, Fluctuations in the air characteristics can be reduced.

[0182] In the insulating film 312a, all the oxygen that has entered the insulating film 312a from the outside is Some oxygen does not move to the outside of the insulating film 312a and remains in the insulating film 312a. As oxygen enters the insulating film 312a, oxygen contained in the insulating film 312a moves out of the insulating film 312a. This may cause oxygen to move in the insulating film 312a.

[0183] When an oxide insulating film that transmits oxygen is formed as the insulating film 312a, The oxygen desorbed from the insulating film 312b is guided to the oxide semiconductor film 312b through the insulating film 312a. It can be moved to 308a and 308b.

[0184] An insulating film 312b is formed in contact with the insulating film 312a. The oxide insulating film is formed using an oxide insulating film containing more oxygen than the oxygen that satisfies the stoichiometric composition. When an oxide insulating film contains more oxygen than the stoichiometric composition, some of the oxygen is removed by heating. The oxide insulating film containing more oxygen than the stoichiometric composition has a TD In S analysis, the amount of oxygen desorbed, converted to oxygen atoms, was 1.0 x 10 18 atoms / cm 3 or more, preferably 3.0 × 10 20 atoms / cm 3 The oxide insulating film is as described above. The surface temperature of the film during the TDS analysis was 100°C or higher and 700°C or lower. The temperature is preferably in the range of 100°C or higher and 500°C or lower.

[0185] The insulating film 312b has a thickness of 30 nm to 500 nm, preferably 50 nm or more. Silicon oxide, silicon oxynitride, etc., of 400 nm or less can be used.

[0186] Furthermore, it is preferable that the insulating film 312b has a small number of defects. The spin density of the signal at g=2.001 originating from the silicon dangling bond is 1.5 x 10 18 spins / cm 3 Less than or even 1×10 18 spins / cm 3 Below It is preferable that the insulating film 312b has a thickness of 1000 nm or less than that of the insulating film 312a. Since it is separated from the conductor films 308a and 308b, the defect density is higher than that of the insulating film 312a. Good too.

[0187] The insulating film 314 is made of a material containing a blocking agent such as oxygen, hydrogen, water, alkali metals, and alkaline earth metals. By providing a nitride insulating film having a blocking effect, the oxide semiconductor films 308a, 308b, and The diffusion of oxygen from the metal oxide film 308c to the outside can be prevented. Examples of the material include silicon nitride, silicon nitride oxide, aluminum nitride, and aluminum nitride oxide. be.

[0188] In addition, it has a blocking effect against oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. An oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like is provided over the nitride insulating film. As the oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like, aluminum oxide Aluminum, aluminum oxide nitride, gallium oxide, gallium oxide nitride, yttrium oxide , yttrium oxide nitride, hafnium oxide, hafnium oxide nitride, etc. To control the capacitance of the element, oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. A nitride insulating film or an oxide insulating film may be appropriately provided on the nitride insulating film having a blocking effect. stomach.

[0189] In addition, a conductive film 316b is formed on the insulating film 314. The conductive film 316b is a capacitor element. The electrode can function as a terminal electrode.

[0190] The conductive film 316b can be formed using a light-transmitting conductive material. Examples of conductive materials with optical properties include indium oxide containing tungsten oxide, tungsten oxide, Indium zinc oxide containing tin oxide, indium oxide containing titanium oxide, titanium oxide Indium tin oxide, ITO, indium zinc oxide, silicon oxide-doped indium Examples include zinc tin oxide.

[0191] The organic insulating film 317 is made of organic resin such as acrylic resin, polyimide, or epoxy resin. The organic insulating film 317 may preferably have a thickness of 500 nm or more and 5000 nm or less. The thickness of the organic insulating film 317 is set to the above thickness. By doing so, it is possible to fill the recesses on the conductive film 316b with the organic insulating film 317. This reduces the unevenness of the region where the alignment film 320 is formed.

[0192] By forming the organic insulating film 317 using an organic resin, it is possible to form a film that functions at least as a pixel electrode. The recesses of the conductive film 316b can be filled with the organic insulating film 317, and the light emitting element 39 Therefore, in the light emitting element 394, the components constituting the light emitting element 394 can be formed on a flat surface. Short circuits between electrodes and the like are reduced, and the yield can be improved.

[0193] In addition, conductive films 319 and 319a are formed on the organic insulating film 317. The conductive film 319a functions as a pixel electrode. The conductive film 304b and the conductive film 310c are connected to each other through an opening formed in the organic insulating film 317. That is, the conductive film 319a connects the conductive film 304b and the conductive film 310c. It functions as a connecting electrode.

[0194] The organic insulating film 317 is not limited to this. For example, the organic insulating film 317 may be a color filter. For example, the organic insulating film 31 may have the function of a black matrix. When the pixel 7 has a function of a color filter, for example, a red pixel, a blue pixel, a green pixel, In this case, the organic insulating film 317 having color properties may be formed for each color in accordance with the pixels.

[0195] The conductive films 319 and 319a are formed using a light-transmitting conductive material, similar to the conductive film 316b. When the conductive film 319 is used as an anode of the light-emitting element 394, The conductive films 319 and 319a have a larger work function than the light-emitting layer 392 made of indium tin oxide or the like. It is preferable to use a light-transmitting film.

[0196] In order to form a connection structure in which the conductive film 304a and the conductive film 310c are in direct contact with each other, Before forming the film 310c, a pattern is formed to form openings in the insulating films 305 and 306. However, as shown in FIG. 6, the conductive film 3 The conductive film 304a and the conductive film 310c are connected by the conductive film 19a. This eliminates the need to form a connection portion where the conductive film 310c is in direct contact with the conductive film 310a, and reduces the number of photomasks by one. That is, the number of manufacturing steps of the display device can be reduced.

[0197] Furthermore, on the organic insulating film 317 and the conductive film 319, a light emitting element 394 is provided to separate adjacent pixels. An insulating layer 391 is formed on the substrate 390, which has a function of isolating the electrodes, i.e., a function as a partition wall. The material 391 may be an organic insulating film or an inorganic insulating film, as long as it has insulating properties. The organic insulating film may be, for example, a polyimide resin or a polyamide resin. acrylic resin, siloxane resin, epoxy resin, or phenolic resin, etc. As the inorganic insulating film, silicon oxide, silicon oxynitride, etc. may be used. In particular, by using a photosensitive organic resin material, the insulating layer 391 can be easily manufactured. This is preferable because

[0198] In addition, a light-emitting layer 392 is formed on the conductive film 319 and the insulating layer 391. 92 is sufficient as long as it has a light-emitting layer containing at least a light-emitting substance. In addition, the layer may have functions such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a charge generation layer. The light-emitting layer 392 may be formed by a pair of electrodes (here, a conductive film 319 and a Electrons and holes are injected from the conductive film 393, causing a current to flow. Then, the electrons and holes are recombined. By doing so, the luminescent substance forms an excited state, and when the excited state returns to the ground state, It can emit light.

[0199] In addition, a conductive film 393 is formed on the light-emitting layer 392. When the conductive film 393 is used as the cathode of the light emitting element 394, the conductive film 393 has a work function that can inject electrons into the light emitting element 394. It is preferable to form the layer using a material with a small work function. A layer of alkali metal or alkaline earth metal with a small work function is formed to a thickness of several nanometers. On top of that, a metal material such as aluminum or a conductive material such as indium tin oxide is formed. The buffer layer may be formed using an oxide material or a semiconductor material having a high thermal conductivity. , alkaline earth metal oxides, halides, or alloys such as magnesium-silver The light emitted from the light emitting layer 392 can be red (R), green (G), or blue (B). ) can be used. Other light emitting devices that emit white, yellow, or other colors can also be used. It is possible.

[0200] If the light emitted from the light-emitting layer 392 is white, a colored layer (not shown) is formed on the substrate 302. A film (colored film) having a function as a color filter may be formed. In addition, a light-shielding film adjacent to the colored film can be formed on the substrate 302. The light-shielding film is a blue It functions as a rack matrix. Also, as a configuration in which a color conversion layer is provided instead of a colored film, If the display device is a monochrome display, it does not need to be provided.

[0201] The colored film may be a film that transmits light in a specific wavelength band. For example, a red wavelength A red (R) color filter that transmits light in the long wavelength band, and a green (R) color filter that transmits light in the green wavelength band. (G) color filter, and blue (B) color filter that transmits light in the blue wavelength band. etc. can be used.

[0202] The light-shielding film may be any film, such as a metal film, as long as it has the function of blocking light in a specific wavelength range. Alternatively, an organic insulating film containing a black pigment or the like can be used.

[0203] In addition, the space between the substrate 342 and the substrate 302 is provided with a protective layer to prevent deterioration of the light emitting element 394 due to moisture. In order to prevent this, a desiccant may be provided. Alternatively, a liquid crystal layer or resin may be used to fill the space. .

[0204] 2B is a cross-sectional view of the pixel 301 in which the liquid crystal element 31 is used. 42. In FIG. 42, in addition to the element substrate having the configuration described in this embodiment, The counter substrate 997 has a counter electrode 998. The liquid crystal 999 is filled between the substrates, and the liquid crystal between the counter electrode and the pixel electrode forms a liquid crystal element. Form.

[0205] Regarding a method for manufacturing an element portion provided on the substrate 302 shown in the display device shown in FIG. 6, 12. Here, the element portion provided on the substrate 302 is , refers to the region sandwiched between the substrate 302 and the conductive film 393.

[0206] The films that make up a transistor (insulating film, oxide semiconductor film, metal oxide film, conductive film, etc.) are Sputtering, Chemical Vapor Deposition (CVD), Vacuum Evaporation, Pulsed Laser Deposition (PLD) Alternatively, it can be formed by a coating method or a printing method. The typical film formation methods are sputtering and plasma enhanced chemical vapor deposition (PECVD). However, thermal CVD may also be used. An example of a thermal CVD method is MOCVD (metal organic chemical vapor deposition). Alternatively, a deposition (multilayer deposition) method or an atomic layer deposition (ALD) method may be used.

[0207] In the thermal CVD method, the chamber is kept at atmospheric pressure or reduced pressure, and the source gas and oxidant are simultaneously mixed in the chamber. The film is formed by sending the gas into the chamber, reacting it near or on the substrate, and depositing it on the substrate. As described above, the thermal CVD method is a film formation method that does not generate plasma. This has the advantage that defects are not generated due to damage.

[0208] In the ALD method, the chamber is kept at atmospheric pressure or reduced pressure, and the source gases for the reaction are sequentially introduced. Next, the gas is introduced into the chamber, and the film is formed by repeating this gas introduction sequence. By switching each switching valve (also called high-speed valve), two or more types of raw material gas can be The first and second source gases are supplied to the chamber in order to prevent the multiple source gases from mixing. At the same time or afterwards, an inert gas (argon, nitrogen, etc.) is introduced to If an inert gas is introduced at the same time, the inert gas is introduced as a carrier gas. In addition, an inert gas may be introduced at the same time as the second source gas is introduced. Instead of introducing an inert gas, the first source gas is discharged by evacuation, and then the second source gas is introduced. A source gas may be introduced. The first source gas is adsorbed on the surface of the substrate to form a first monoatomic layer. The second monolayer is formed on the first monolayer by reacting with the second source gas introduced later. The thin film is formed by stacking the layers.

[0209] By controlling the gas introduction order and repeating this process multiple times until the desired thickness is achieved, the step coverage is improved. The thickness of the thin film can be increased by repeating the gas introduction sequence. This allows precise film thickness control, making it possible to fabricate minute transistors. It is suitable for manufacturing.

[0210] First, prepare a substrate 302. Here, a glass substrate is used as the substrate 302.

[0211] Next, a conductive film is formed on the substrate 302 and processed into a desired region. The conductive films 304a, 304b, and 304c are formed. The formation of the mask is performed by forming a mask in a desired region by a first patterning. It can be formed by etching the unprotected area (see FIG. 7(A)).

[0212] The conductive films 304a, 304b, and 304c are typically formed by a sputtering method, a vacuum evaporation method, or the like. The film can be formed by deposition, PLD, thermal CVD, or the like.

[0213] In addition, conductive films 304a, 304b, and 304c are formed by a film forming apparatus using ALD. In this case, WF6 gas and B2H6 gas are sequentially used. The initial tungsten film is formed by repeatedly introducing WF6 gas and H2 gas at the same time. The tungsten film is formed by introducing SiH4 gas instead of B2H6 gas. good.

[0214] Next, an insulating film 305 is formed on the substrate 302 and the conductive films 304a, 304b, and 304c. Then, an insulating film 306 is formed on the insulating film 305 (see FIG. 5).

[0215] The insulating film 305 and the insulating film 306 are formed by a sputtering method, a CVD method, a vacuum deposition method, a PLD method, or the like. The insulating film 305 and the insulating film 306 can be formed by a thermal CVD method or the like. It is preferable to form the layers continuously in a vacuum, since this prevents the inclusion of impurities.

[0216] The insulating film 305 and the insulating film 306 are formed as a silicon oxide film or a silicon oxynitride film. In this case, it is preferable to use a deposition gas containing silicon and an oxidizing gas as the source gas. Representative examples of silicon-containing deposition gases include silane, disilane, trisilane, Examples of oxidizing gases include oxygen, ozone, nitrous oxide, and nitrogen dioxide. etc.

[0217] When a gallium oxide film is formed as the insulating film 305 and the insulating film 306, MOCVD is used. The method can be used to form the sintered body.

[0218] The insulating film 305 and the insulating film 306 are formed by a thermal CVD method such as MOCVD or an ALD method. When a hafnium oxide film is formed using a solvent containing a hafnium precursor compound, Liquid (hafnium alkoxide solution, typically tetrakisdimethylamidohafnium ( Two types of gases are used: vaporized raw material gas (TDMAH) and ozone (O3) as an oxidant. The chemical formula for tetrakisdimethylamidohafnium is Hf[N(CH3)2] 4. Other material liquids include tetrakis(ethylmethylamido)hafnium. There are some.

[0219] The insulating film 305 and the insulating film 306 are formed by a thermal CVD method such as MOCVD or an ALD method. When an aluminum oxide film is formed using the above, a solvent and an aluminum precursor compound are mixed. The raw material gas is made by vaporizing a liquid containing trimethylaluminum (TMA, etc.) and an oxidizer. Two types of gases are used: H2O and Al(CH3 ) 3. Other material liquids include tris(dimethylamido)aluminum, tris(dimethylamido)aluminum, Isobutylaluminum, aluminum tris(2,2,6,6-tetramethyl-3,5 -heptanedionate).

[0220] The insulating film 305 and the insulating film 306 are formed by a thermal CVD method such as MOCVD or an ALD method. When forming a silicon oxide film using hexadichlorodisilane, the film is absorbed onto the surface to be formed. The chlorine contained in the adsorbed material is removed, and the radicals of oxidizing gases (O2, nitrous oxide) are removed. is supplied to react with the adsorbate.

[0221] Next, an oxide semiconductor film 307 is formed over the insulating film 306 (see FIG. 7B).

[0222] The oxide semiconductor film 307 can be formed by a sputtering method, a coating method, a pulsed laser deposition method, a laser It can be formed by using an ablation method, a thermal CVD method, or the like.

[0223] The sputtering gas is a rare gas (typically argon), oxygen, or a mixture of rare gas and oxygen. In the case of a mixture of rare gas and oxygen, the gas ratio of oxygen to rare gas is It is preferable to increase

[0224] The target may be appropriately selected depending on the composition of the oxide semiconductor film to be formed.

[0225] Note that when the oxide semiconductor film is formed by, for example, a sputtering method, the substrate temperature The temperature is 150°C or higher and 750°C or lower, preferably 150°C or higher and 450°C or lower, and more preferably The oxide semiconductor film is formed at a temperature of 200°C or higher and 350°C or lower. A film can be formed.

[0226] In addition, the following conditions are preferably applied to form the CAAC-OS film.

[0227] By suppressing the inclusion of impurities during film formation, it is possible to prevent the crystal state from being destroyed by impurities. For example, the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be reduced. In addition, the impurity concentration in the deposition gas can be reduced. A deposition gas having a temperature of 80° C. or less, preferably −100° C. or less, is used.

[0228] Oxide semiconductor films, such as InGaZnO, are formed using a deposition system that uses ALD. X (X>0) membrane When forming a film, In(CH3)3 gas and O3 gas are introduced in sequence repeatedly to form InO2 Then, Ga(CH3)3 gas and O3 gas are introduced simultaneously to form a GaO layer. Then, Zn(CH3)2 gas and O3 gas are introduced simultaneously to form a ZnO layer. The order of these layers is not limited to this example. layer, and mixed compound layers such as InZnO2 layer, GaInO layer, ZnInO layer, and GaZnO layer It is also possible to form a H2O gas bubbled with an inert gas such as Ar instead of O3 gas. However, it is preferable to use O3 gas that does not contain H. In(CH3 In place of In(C2H5)3 gas, Ga(CH3)3 gas may be used. Instead of gas, Ga(C2H5)3 gas may be used. It's fine.

[0229] Next, the oxide semiconductor film 307 is processed into a desired region, whereby an island-shaped oxide semiconductor film 30 The oxide semiconductor films 308a, 308b, and 308d are formed. 8d is a step of forming a mask by second patterning in a desired region, and forming a film covered by the mask. The etching can be done by etching the unetched area. Use dry etching, wet etching, or a combination of both. (See Figure 7(C)).

[0230] After that, heat treatment is performed to remove the oxide semiconductor films 308a, 308b, and 308d. The hydrogen, water, and the like contained in the oxide semiconductor films 308a, 308b, and 308d are released. As a result, the oxygen concentration and the water concentration of the purified oxide semiconductor film 308a , 308b, 308d can be formed. The temperature of the heat treatment is typically 25 The temperature is 0°C or higher and 650°C or lower, preferably 300°C or higher and 500°C or lower. The temperature is typically 300°C or higher and 400°C or lower, preferably 320°C or higher and 370°C or lower. By doing so, it is possible to reduce warpage and shrinkage of the board even in large area boards. This improves the yield.

[0231] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, heat treatment can be performed at a temperature above the strain point of the substrate for a short period of time. It is possible to shorten the processing time and reduce the warping of the substrate during the heat treatment. This is particularly preferable for large area substrates.

[0232] The heat treatment is carried out in nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably air at 1 ppm or less, preferably 10 ppb or less), or rare gases (argon, helium The above-mentioned nitrogen, oxygen, ultra-dry air, or rare gas may be added to hydrogen. It is preferable that the mixture does not contain water or the like. After the heat treatment in a nitrogen or rare gas atmosphere, Heating may be performed in an oxygen or ultra-dry air atmosphere. Hydrogen, water, and the like can be desorbed and oxygen can be supplied to the oxide semiconductor film. As a result, the amount of oxygen vacancies in the oxide semiconductor film can be reduced.

[0233] When the temperature for forming the insulating film 311a to be formed later is set to 280° C. or more and 400° C. or less, and desorbing hydrogen, water, and the like from the oxide semiconductor films 308a, 308b, and 308d. Therefore, the heat treatment is not necessary.

[0234] Next, a conductive film 303 is formed over the insulating film 306 and the oxide semiconductor films 308a, 308b, and 308d. 9 is formed (see FIG. 8(A)).

[0235] The conductive film 309 is formed by using a sputtering method, a vacuum deposition method, a PLD method, a thermal CVD method, or the like. It is possible.

[0236] Next, the conductive film 309 is processed into desired regions to form conductive films 310a, 310b, and 310 The conductive films 310a, 310b, 310c, 310d, 310e, and 310f are formed. The formation of 310c, 310d, 310e, and 310f is performed by a third patterning in the desired area. A mask is formed and the area not covered by the mask is etched to form the This is possible (see FIG. 8(B)).

[0237] Next, the insulating film 306, the oxide semiconductor films 308a, 308b, and 308d, and the conductive film 310 An insulating film 311 is formed on the surfaces of 310a, 310b, 310c, 310d, 310e, and 310f. The insulating film 311 is formed by laminating layers 311a and 311b (see FIG. 8(C)). can be formed by sputtering, CVD, vapor deposition, or the like.

[0238] After the insulating film 311a is formed, the insulating film 311b is successively formed without exposing it to the atmosphere. After the insulating film 311a is formed, the flow rate of the source gas is controlled without exposing the insulating film 311a to the atmosphere. The insulating film 311b is continuously formed by adjusting one or more of the pressure, the high frequency power, and the substrate temperature. This reduces the concentration of impurities originating from atmospheric components at the interface between the insulating films 311a and 311b. In addition, oxygen contained in the insulating film 311b can be removed by the oxide semiconductor films 308a and 308b. The oxide semiconductor films 308a, 308b, and 308d can be transferred to the oxide semiconductor films 308a, 308b, and 308d. The amount of oxygen vacancy in 8d can be reduced.

[0239] The insulating film 311a is formed by mixing an oxidizing gas with a concentration of more than 20 times but less than 100 times the deposition gas. and the pressure in the processing chamber is set to less than 100 Pa, preferably 5 By using the CVD method at 0 Pa or less, oxide insulation containing nitrogen and with few defects can be obtained. A film can be formed.

[0240] The source gas for the insulating film 311a is a deposition gas containing silicon and an oxidizing gas. Representative examples of silicon-containing deposition gases include silane, disilane, trisilane, and thiazolinone. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, and Nitric oxide, etc.

[0241] By using the above conditions, an oxide insulating film that transmits oxygen is formed as the insulating film 311a. Furthermore, by providing the insulating film 311a, the shape of the insulating film 311b to be formed later can be controlled. Damage to the oxide semiconductor films 308a, 308b, and 308d can be reduced during the deposition process. is.

[0242] The insulating film 311b is formed on a substrate placed in a processing chamber of a plasma CVD apparatus that has been evacuated. The plate is maintained at a temperature of 180°C or higher and 280°C or lower, more preferably 200°C or higher and 240°C or lower, The raw material gas is introduced into the processing chamber, and the pressure in the processing chamber is set to 100 Pa or more and 250 Pa or less, More preferably, the pressure is 100 Pa or more and 200 Pa or less, and the pressure applied to the electrode provided in the processing chamber is 0.1 7W / cm 2 More than 0.5W / cm 2 or less, more preferably 0.25 W / cm 2 Over 0. 35W / cm 2 Under the following conditions of high frequency power supply, silicon oxide film or oxynitride film A silicon film is formed.

[0243] As the source gas for the insulating film 311b, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of silicon-containing deposition gases include silane, disilane, trisilane, and thiazolinone. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, and Nitric oxide, etc.

[0244] As a film forming condition for the insulating film 311b, high frequency power is supplied to the source gas in the plasma. The decomposition efficiency of the insulating film 311 increases, oxygen radicals increase, and oxidation of the source gas progresses. However, the oxygen content in the substrate b is higher than the stoichiometric ratio. At the temperature for forming the insulating film 311b, the bonding strength between silicon and oxygen is weak, so that the oxygen is easily converted by heating. As a result, the oxygen content is greater than the stoichiometric composition. An oxide insulating film from which part of oxygen is released by heating can be formed. An insulating film 311a is provided on the conductor films 308a, 308b, and 308d. In the step of forming the insulating film 311b, the insulating film 311a is formed on the oxide semiconductor films 308a and 308b. As a result, the oxide semiconductor films 308a, 308b, and 308d are formed as protective films. The insulating film 311b is formed using high-frequency power with high power density while reducing damage to the It is possible.

[0245] In the film formation conditions for the insulating film 311b, the deposition gas containing silicon is mixed with the oxidizing gas. By increasing the flow rate of the gas, it is possible to reduce the number of defects in the insulating film 311b. Specifically, ESR measurements reveal that the g value is 2.001, which is due to the dangling bond of silicon. The spin density of the signal that appears is 6×10 17 spins / cm 3 Less than 3 x 10 1 7 spins / cm 3 Less than or equal to 1.5 × 10 17 spins / cm 3 is An oxide insulating film with a small number of defects can be formed. As a result, the reliability of the transistor can be improved. It can be increased.

[0246] Next, a heat treatment is performed. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate distortion point. Preferably, the temperature is 200°C or higher and 450°C or lower, and more preferably, 300°C or higher and 450°C or lower. The temperature of the heat treatment is typically 300°C or higher and 400°C or lower, preferably 3 By keeping the temperature between 20℃ and 370℃, warping and shrinkage of the substrate can be prevented even in large area substrates. This allows for a reduction in the number of defects, thereby improving yield.

[0247] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, the heat treatment can be performed at a temperature above the distortion point of the substrate for a short period of time. This can reduce processing time.

[0248] Heat treatment is carried out in nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably 1 ppm). m or less, preferably 10 ppb or less of air), or rare gases (argon, helium, etc.) The reaction may be carried out under an atmosphere of nitrogen, oxygen, ultra-dry air, or a rare gas, hydrogen, water, etc. It is preferable that it does not contain

[0249] By this heat treatment, part of oxygen contained in the insulating film 311b is oxidized to the oxide semiconductor film 308a, 308b and 308d, and As a result, oxygen vacancies in the oxide semiconductor films 308a and 308b can be reduced. , 308d, the amount of oxygen vacancies can be further reduced.

[0250] In addition, when the insulating films 311a and 311b contain water, hydrogen, etc., they are blocked by the insulating films 311a and 311b. When an insulating film 313 having the function of forming the insulating film 311a and the insulating film 311b is formed later and subjected to heat treatment, the insulating films 311a and 311b are formed. Water, hydrogen, and the like contained in the oxide semiconductor films 308a, 308b, and 308d are transferred to the oxide semiconductor films 308a, 308b, and 308d. Defects occur in the oxide semiconductor films 308a, 308b, and 308d. This heating can remove water, hydrogen, etc. contained in the insulating films 311a and 311b. This reduces the variation in the electrical characteristics of the transistors and also suppresses the fluctuation in the threshold voltage. It can be controlled.

[0251] The insulating film 311b is formed on the insulating film 311a while heating, whereby the oxide semiconductor Oxygen is transferred to the oxide semiconductor films 308a, 308b, and 308d. Since it is possible to reduce the oxygen vacancies contained in 308d, the heat treatment is not required. It's good to

[0252] In addition, when the conductive films 310a, 310b, 310d, 310e, and 310f are formed, the conductive films The oxide semiconductor films 308a, 308b, and 308d are damaged by the etching. , the back channels of the oxide semiconductor films 308a and 308b (the oxide semiconductor films 308a and 308b) 8b, the surface opposite to the conductive films 304a and 304c that function as gate electrodes However, oxygen vacancies occur on the insulating film 311b side. By using an oxide insulating film containing more oxygen than the back-channel insulating film, Oxygen vacancies occurring on the channel side can be repaired. The defects contained in a and 308b can be reduced, improving the reliability of the transistor. It can be done.

[0253] Note that the heat treatment may be performed after the opening 362, which will be formed later, is formed.

[0254] Next, the insulating films 311a and 311b are processed into desired regions, so that the insulating films 312a and The insulating film 312 is formed by laminating the insulating film 312b and the insulating film 312, and the opening 362 is formed. 12, and the formation of the opening 362 is performed by forming a mask by a fourth patterning in the desired area. and then etching the areas not covered by the mask. (See Figure 9(A)).

[0255] Note that the opening 362 is formed so that the surface of the oxide semiconductor film 308d is exposed. The portion 362 can be formed by, for example, dry etching. It is preferable to etch the insulating film 311 by an etching method. Since the oxide semiconductor film 308d is exposed to plasma during etching, However, it is possible to increase the oxygen vacancies in the opening 362. Examples of the etching method include, but are not limited to, a wet etching method, or a dry etching method and a wet etching method. A forming method in which a tungsten etching method is combined may also be used.

[0256] Next, an insulating film 314 is formed over the insulating film 312 and the oxide semiconductor film 308d (FIG. 9(B) )reference.).

[0257] The insulating film 314 is formed by removing impurities from the outside, such as oxygen, hydrogen, water, alkali metals, and alkali metals. It is preferable to use a material that prevents the alkali-earth metal or the like from diffusing into the oxide semiconductor film. Furthermore, it is preferable that the insulating material contains hydrogen, and typically contains nitrogen, for example, a nitride insulating material. The insulating film 314 can be formed by, for example, a CVD method or a sputtering method. The method can be used to form the sintered body.

[0258] When the insulating film 314 is formed by plasma CVD or sputtering, an oxide semiconductor film The insulating film 314 is exposed to plasma, and oxygen vacancies are generated in the oxide semiconductor film. External impurities, such as water, alkali metals, and alkaline earth metals, may impair the oxide semiconductor film. The insulating film 3 is made of a material that prevents diffusion of hydrogen into the When the hydrogen in the oxide semiconductor film 308d is diffused into the oxide semiconductor film 308d, Hydrogen bonds with oxygen to generate electrons, which are carriers. When hydrogen enters the oxygen vacancy, electrons are generated as carriers. The metal oxide semiconductor film 308d becomes highly conductive and turns into the metal oxide film 308c.

[0259] In addition, the silicon nitride film is preferably formed at a high temperature in order to enhance blocking properties. For example, the substrate temperature is 100°C or higher and 400°C or lower, more preferably 300°C or higher and 400°C or lower. It is preferable to form the film by heating at the following temperature. Oxygen is released from the oxide semiconductor used as the dielectric films 308a and 308b, and the carrier concentration increases. Therefore, the temperature should be set at a level at which such a phenomenon does not occur.

[0260] Next, a conductive film 315 is formed over the insulating film 314 (see FIG. 10A).

[0261] The conductive film 315 can be formed by, for example, a sputtering method.

[0262] Next, the conductive film 315 is processed into a desired region to form a conductive film 316b. The conductive film 316b is formed by forming a mask in a desired region by a fifth patterning process. The area not covered by the mask can be etched (FIG. 10( See B). ).

[0263] Next, an organic insulating film 317 is formed so as to cover the insulating film 314 and the conductive film 316b (FIG. 10 The organic insulating film 317, which functions as a planarizing film, is formed on the insulating film 313 and the conductive film 314. Each of the electrodes 316b has an opening so that a portion of the electrode 316b is exposed.

[0264] The organic insulating film 317 is formed by applying a photosensitive composition using a coating method such as spin coating or dip coating. After the composition is applied onto the insulating film 313 and the conductive film 316b, a film is formed using a sixth photomask. The composition is exposed and developed in a photolithography process, and then heated to form the film. When a non-photosensitive composition is applied to the insulating film 313 and the conductive film 316b, A resist is applied onto the non-photosensitive composition, and photolithography is performed using a sixth photomask. A mask is formed by processing the resist by a photolithography process, and a non-photosensitive composition is applied using the mask. By etching, the organic insulating film 317 can be formed.

[0265] The organic insulating film 317 is formed by a wet method such as an inkjet method or a printing method. This allows the number of photomasks to be reduced.

[0266] Next, using the organic insulating film 317 as a mask, the insulating films 305, 306, 312, and the insulating film 314 are etched to form an opening 3 exposing the conductive film 304b. 64a, an opening 364b exposing the conductive film 310c, and an opening 364c exposing the conductive film 310e. 64c is formed (see FIG. 11(A)).

[0267] Next, a conductive film 318 is formed (see FIG. 11B).

[0268] The conductive film 318 can be formed by, for example, a sputtering method.

[0269] Next, the conductive film 318 is processed into desired regions to form conductive films 319 and 319a. The conductive films 319 and 319a are formed in desired regions by a mask patterning process using the seventh patterning method. The mask can be formed by etching the area not covered by the mask. This is possible (see Figure 11(C)).

[0270] Next, an insulating layer is formed and processed into a desired region to form an insulating layer 391. The insulating layer 391 is formed by forming a mask by the eighth patterning in a desired region. It can be formed by etching the areas not covered by the mask (Figure 12(A) )reference.).

[0271] The insulating layer 391 functioning as a partition wall has a tapered or continuous curvature on its sidewall. It is preferable to form the sidewall of the insulating layer 391 so as to have an inclined surface formed by the inclined surface. By forming the insulating film 390 in this shape, the covering property of the light-emitting layer 392 and the conductive film 393 to be formed later can be improved. It can be said that.

[0272] Next, a light-emitting layer 392 and a conductive film 393 are formed (see FIG. 12B). The conductive film 319, which functions as a light-emitting layer, the light-emitting layer 392, and the conductive film 393 are stacked. , a light emitting element 394 can be formed.

[0273] Through the above steps, a pixel portion having a transistor and a driver circuit shown in FIGS. 5 and 6 are formed on the substrate 302. A display device having an operating circuit portion can be formed. In this example, the first to eighth patternings, i.e., eight photomasks, are used to pattern the transistors. The capacitor and the capacitor element can be formed simultaneously.

[0274] In this embodiment, hydrogen contained in the insulating film 314 is diffused into the oxide semiconductor film 308d. The conductivity of the oxide semiconductor film 308d was increased by the addition of the oxide semiconductor film 308a and the oxide semiconductor film 308b. b is covered with a mask, and impurities, typically hydrogen, boron, or phosphorus, are introduced into the oxide semiconductor film 308d. , tin, antimony, rare gas elements, alkali metals, alkaline earth metals, etc. are added to The conductivity of the oxide semiconductor film 308d may be increased by adding hydrogen, boron, or The methods of adding phosphorus, tin, antimony, rare gas elements, etc. include ion doping, On the other hand, the oxide semiconductor film 308d is formed by ion implantation. The metal or the like is added by applying a solution containing the impurity to the oxide semiconductor film 308d. There is a way.

[0275] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0276] (Embodiment 3) In this embodiment, a display device including a transistor different from that in Embodiment 2 will be described with reference to FIG. 3 to 19 will be used to explain this.

[0277] The display device shown in FIG. 13 has a dual gate structure transistor in the driving circuit section indicated by AB. The semiconductor device is characterized by having a transistor 102a.

[0278] The transistor 102a provided in the driver circuit section has a gate electrode provided on the substrate 302. and insulating films 305 and 306 which function as gate insulating films. The oxide semiconductor film 308a formed over the insulating film 306 and the oxide semiconductor film 308a and conductive films 310a and 310b functioning as a source electrode and a drain electrode. In addition, insulating films 312 and 313 are formed over the oxide semiconductor film 308a and the conductive films 310a and 310b. 4 is formed, and a conductive film 316d that functions as a gate electrode is formed on the insulating film 314. The conductive film 316d functioning as a gate electrode is formed by the insulating film 305, the insulating film 306, and the insulating film 307. 12 and an opening (not shown) formed in the insulating film 314, That is, the conductive film 304a and the conductive film 316d are at the same potential. is.

[0279] Therefore, by applying the same voltage to each gate electrode of the transistor 102a, Reduction of characteristic variations, suppression of deterioration in GBT stress tests, and performance at different drain voltages In addition, the oxide semiconductor film 308a In this case, the area in which carriers flow is larger in the film thickness direction, and therefore the carrier movement As a result, the on-current of the transistor 102a increases and the field effect The mobility is high, typically with a field effect mobility of 20 cm 2 / V·s or more.

[0280] At the edge of the oxide semiconductor film processed by etching or the like, damage caused by the processing may occur. This causes defects and contamination due to the adhesion of impurities, which can lead to stresses such as electric fields. When given, it is easily activated, which makes it easy to become n-type (low resistance). Therefore, the edge of the oxide semiconductor film 308a overlapping with the conductive film 304a functioning as a gate electrode The n-type end portion is easily converted to n-type. When the n-type region is provided between the conductive films 310a and 310b, which function as a capacitor, However, the channel width direction is In this case, the conductive film 316d that functions as a gate electrode is provided. The side surfaces of the oxide semiconductor film 308a and the conductive film 316d are affected by the electric field of the conductive film 316d. As a result, the occurrence of parasitic channels at the edge including the side surface and the vicinity thereof is suppressed. A transistor with excellent electrical characteristics, in which the drain current rises sharply with the threshold voltage. This becomes:

[0281] Note that the conductive film 316d functioning as a gate electrode is the same as the conductive film 316b shown in Embodiment 2. The same materials as those mentioned above can be used appropriately.

[0282] <Variation 1> The display device shown in FIG. 13 of this embodiment uses a dual gate as a transistor in a driver circuit portion. As shown in Figure 14, the transistor is fabricated using a gate structure. The driver circuit includes a transistor 102a having a dual gate structure, and the A transistor 103a having a dual gate structure may be used in the pixel portion.

[0283] The transistor 103a is formed by a conductive film 303 which functions as a gate electrode and is provided over a substrate 302. 04c, insulating films 305 and 306 which function as a gate insulating film 51, and The oxide semiconductor film 308b to be formed and the source electrode and the The gate electrode 310a and the gate electrode 310b have conductive films 310d and 310e, which function as drain electrodes. Insulating films 312 and 314 are formed on the conductive film 308b and the conductive films 310d and 310e. A conductive film 316e functioning as a gate electrode is formed over the film 314. The functional conductive film 316e is provided on the insulating films 305 and 306 and the insulating films 312 and 314. In the opening (not shown), a conductive film 304c is formed. That is, the conductive film 304c and the conductive film 316e have the same potential.

[0284] The pixel section, together with the driver circuit section, is made up of devices with high reliability, large on-current, and high field-effect mobility. By providing a transistor with a dual gate structure, a display device with excellent display quality can be manufactured. It is possible.

[0285] <Variation 2> In the display device shown in the second or third embodiment, as shown in FIG. The region overlapping the transistor 102a provided in the path portion and on the organic insulating film 317 A conductive film 319b formed at the same time as the conductive film 319 may be provided on the conductive film 319. The potential can be any potential such as a common potential, a ground potential, etc. By providing the conductive film 319b overlapping the transistor 102a, the gate An electric field generated by a voltage applied to the conductive film 316d, which functions as an electrode, is applied to the conductive film 319. b can be shielded.

[0286] <Variation 3> In the second or third embodiment, the organic insulating film 317 is formed in the driving circuit section and the pixel section. 16, the display device having the organic insulating film 317a only in the pixel portion has been described. It may be provided.

[0287] In the display device shown in FIG. 16, the insulating film 314 is formed as shown in FIG. Thereafter, a mask is formed by patterning, and insulating films 305, 306, 312 and 314 are etched to form openings. After forming the conductive film 315, a conductive film 316b shown in FIG. 10(B) is formed. A conductive film 319a is formed to connect the conductive film 304b and the conductive film 310c. An organic insulating film 317 and a conductive film 319 are formed.

[0288] As shown in FIG. 17, when the organic insulating film 317 is not provided in the drive circuit section, the dual gate A conductive film 316d is formed on the conductive film 316d, which functions as a gate electrode of the transistor 102b having a gate structure. A conductive film 319c formed simultaneously with the film 319 may be provided.

[0289] In addition to the configuration of FIG. 17, as described in FIG. 1(B) of the first embodiment, the conductive film 31 9 is used to connect the conductive film 310e and the conductive film 316b of the transistor 103. This may also be configured as follows.

[0290] In addition to the configuration of FIG. 17, as explained in FIG. 1(C) of the first embodiment, 19 in which the conductive film 310e of the capacitor 103 and the metal oxide film 308c are in direct contact with each other. good.

[0291] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0292] (Fourth embodiment) The transistors 102, 102a, 102b, and 102 In the case of c, 103, 103a, and 103b, an oxide semiconductor film is formed as a stacked structure as needed. Here, the transistor 103 is used for description.

[0293] The transistor shown in FIG. 28 has an oxide film between the insulating film 306 and the conductive films 310d and 310e. A multilayer film 336 including a compound semiconductor film is formed.

[0294] The multilayer film 336 includes an oxide semiconductor film 336a and an oxide semiconductor film 336b. The multilayer film 336 has a two-layer structure. A part of the oxide semiconductor film 336a serves as a channel region. In addition, an insulating film 312a is formed so as to contact the multilayer film 336, The oxide semiconductor film 336b is formed in contact with the insulating film 312a. An oxide semiconductor film 336b is provided between the semiconductor film 336a and the insulating film 312a. .

[0295] The oxide semiconductor film 336b is composed of one or more elements constituting the oxide semiconductor film 336a. The oxide semiconductor film 336b contains at least one of the elements constituting the oxide semiconductor film 336a. Therefore, the oxide semiconductor film 336a is formed at the interface between the oxide semiconductor film 336a and the oxide semiconductor film 336b. Therefore, the movement of carriers is not hindered at the interface. This increases the field effect mobility of the transistor.

[0296] The oxide semiconductor film 336b is typically an In—Ga oxide, an In—Zn oxide, or an In— M-Zn oxide (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf ) and the energy of the bottom of the conduction band is closer to the vacuum level than that of the oxide semiconductor film 336a. Typically, the energy of the bottom of the conduction band of the oxide semiconductor film 336b is The difference in energy between the lower end of the conduction band of the film 336a and the lower end of the conduction band of the film 336a is 0.05 eV or more, 0.07 eV or more , 0.1 eV or more, or 0.15 eV or more and 2 eV or less, 1 eV or less, 0.5 eV That is, the electron affinity of the oxide semiconductor film 336b and the oxide The difference between the electron affinity of the nitride semiconductor film 336a and the electron affinity of the nitride semiconductor film 336b is 0.05 eV or more, 0.07 eV or more, or 0.08 eV or more. 0.1eV or more, or 0.15eV or more and 2eV or less, 1eV or less, 0.5eV or less , or 0.4 eV or less.

[0297] The oxide semiconductor film 336b contains In, which increases carrier mobility (electron mobility). This is preferable.

[0298] The oxide semiconductor film 336b may include Al, Ti, Ga, Y, Zr, La, Ce, Nd, and Sn. Alternatively, having Hf at a higher atomic ratio than In may have the following effects. 1) The energy gap of the oxide semiconductor film 336b is increased. (2) The oxide semiconductor film (3) Reduce the electron affinity of 336b. (4) Shield impurities from outside. (5) Oxide (5) Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, and Hf are metal elements with strong bonding strength with oxygen, so they are Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf is used in a higher atomic ratio than In. This makes it difficult for oxygen deficiency to occur.

[0299] When the oxide semiconductor film 336b is an In-M-Zn oxide, I excluding Zn and O The atomic ratio of n to M is 50% when the sum of In and M is 100 atomic %. atomic %, M is 50 atomic % or more, and more preferably In is 25 atomic % or more. omic% or less, and M is 75 atomic% or more.

[0300] The oxide semiconductor film 336a and the oxide semiconductor film 336b are made of In-M-Zn oxide. In this case, the number of M atoms contained in the oxide semiconductor film 336b is larger than that in the oxide semiconductor film 336a. The number ratio is large, typically, 1 compared to the above atoms contained in the oxide semiconductor film 336a. The atomic ratio is 0.5 times or more, preferably 2 times or more, and more preferably 3 times or more higher.

[0301] The oxide semiconductor film 336a and the oxide semiconductor film 336b are made of In-M-Zn oxide. In this case, the oxide semiconductor film 336b is formed in an atomic ratio of In:M:Zn=x1:y1:z1. When the compound semiconductor film 336a has an atomic ratio of In:M:Zn=x2:y2:z2, y1 / x1 is greater than y2 / x2, and preferably y1 / x1 is 1.5 times or more greater than y2 / x2. More preferably, y1 / x1 is at least twice as large as y2 / x2, and even more preferably Or, y1 / x1 is three times or more larger than y2 / x2. In b, when y2 is equal to or larger than x2, a transistor including the oxide semiconductor film can be stably formed. However, if y2 is three times or more of x2, Since the field-effect mobility of a transistor using an oxide semiconductor film is reduced, y2 is It is preferably less than three times 2.

[0302] For example, the oxide semiconductor film 336a may be made of In:Ga:Zn=1:1:1, In:Ga:Z In-Ga-Zn oxide with an atomic ratio of n=1:1:1.2 or 3:1:2 is used. In addition, the oxide semiconductor film 336b can be formed by In:Ga:Zn=1:3:n (where n is a number of elements). 1:6:m (where m is an integer between 2 and 10), or 1:9:6 The oxide semiconductor film 336 can be made of an In-Ga-Zn oxide having an atomic ratio of 0.1 to 0.2. The atomic ratios of the oxide semiconductor film 336a and the oxide semiconductor film 336b are calculated by adding an error to the above atomic ratios. The oxide semiconductor film 336a includes a variation of minus 20%. is preferably Ga or more, since CAAC-OS is easily formed.

[0303] The oxide semiconductor film 336b is formed as an oxide semiconductor when forming the insulating film 312b to be formed later. It also functions as a membrane for reducing damage to the body membrane 336a.

[0304] The thickness of the oxide semiconductor film 336b is greater than or equal to 3 nm and less than or equal to 100 nm, preferably greater than or equal to 3 nm and less than or equal to 500 nm. Let it be 0 nm.

[0305] Similarly to the oxide semiconductor film 336a, the oxide semiconductor film 336b has a non-single-crystal structure, for example. The non-single crystal structure may be, for example, a CAAC-OS (C Axis Aliphatic Crystal) structure, which will be described later. gned Crystalline Oxide Semiconductor), polyconductor The crystal structure includes a crystalline structure, a microcrystalline structure (described later), or an amorphous structure.

[0306] Note that the oxide semiconductor film 336a and the oxide semiconductor film 336b form an amorphous region. , microcrystalline structure region, polycrystalline structure region, CAAC-OS region, and single crystal structure region. The mixed film may have, for example, an amorphous structure region, The region may be a microcrystalline structure, a polycrystalline structure, a CAAC-OS structure, or a single-crystal structure. It may have a laminated structure of two or more types of regions.

[0307] Here, the oxide semiconductor film 336b is formed between the oxide semiconductor film 336a and the insulating film 312a. Therefore, between the oxide semiconductor film 336b and the insulating film 312a, Even when trap states are formed due to impurities and defects, the trap states and the oxide semiconductor film As a result, electrons flowing through the oxide semiconductor film 336a are separated from the oxide semiconductor film 336a. It is said that it is difficult for the semiconductor to be captured by the trap level, and that it is possible to increase the on-current of the transistor. In addition, when electrons are captured in the trap level, As a result, the threshold voltage of the transistor However, the distance between the oxide semiconductor film 336a and the trap states is Therefore, it is possible to reduce the capture of electrons at the trap level, and the threshold Voltage fluctuations can be reduced.

[0308] In addition, the oxide semiconductor film 336b can block impurities from the outside; The amount of impurities that move from the outside to the oxide semiconductor film 336a can be reduced. Therefore, oxygen vacancies are unlikely to be formed in the oxide semiconductor film 336b. It is possible to reduce the impurity concentration and oxygen vacancy in 336a.

[0309] Note that the oxide semiconductor film 336a and the oxide semiconductor film 336b are simply stacked. The energy of the bottom of the conduction band changes continuously between the layers. In other words, trap centers and recombination centers are formed at the interfaces of each film. The stacked structure is such that there are no impurities that would form defect levels. Impurities are present between the oxide semiconductor film 336a and the oxide semiconductor film 336b. When this happens, the continuity of the energy band is lost, and carriers are trapped or re-trapped at the interface. They combine and disappear.

[0310] To form continuous junctions, a multi-chamber deposition system equipped with a load lock chamber is required. (sputtering equipment) to continuously stack each film without exposing it to the air. Each chamber in the sputtering device is indispensable for the oxide semiconductor film. An adsorption type vacuum pump such as a cryopump is used to remove as much water as possible. High vacuum pumping (5×10 -7 Pa~1×10 -4 It is preferable to Alternatively, a turbomolecular pump and cold trap can be combined to evacuate the chamber from the exhaust system. It is preferable to prevent gases, especially gases containing carbon or hydrogen, from flowing back into the .

[0311] 28, the multilayer film 336 is made up of an oxide semiconductor film 336a and an oxide semiconductor film 33 6b between the insulating film 306 and the oxide semiconductor film 336a. A three-layer structure may be formed by providing a film similar to the semiconductor film 336b. The thickness of the oxide semiconductor film provided between the oxide semiconductor film 336a and the oxide semiconductor film 336b is The thickness of the oxide semiconductor film is preferably 1 nm to 5 nm, By setting the thickness to between 1000 and 3000 nm, the amount of variation in the threshold voltage of the transistor can be reduced. is possible.

[0312] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0313] (Embodiment 5) In the embodiment, in the transistor included in the display device described in the above embodiment, One embodiment applicable to an oxide semiconductor film will be described.

[0314] The oxide semiconductor film is an oxide semiconductor having a single crystal structure (hereinafter referred to as a single-crystal oxide semiconductor), Polycrystalline oxide semiconductors (hereinafter referred to as polycrystalline oxide semiconductors) and microcrystalline oxides A semiconductor having an amorphous structure (hereinafter referred to as a microcrystalline oxide semiconductor) and an oxide semiconductor having an amorphous structure (hereinafter referred to as a The oxide semiconductor film may be formed of one or more of the following: The oxide semiconductor film may be a CAAC-OS film. The oxide semiconductor may be composed of an oxide semiconductor having a crystal grain and a crystal structure. The AAC-OS and the microcrystalline oxide semiconductor will be described.

[0315] First, the CAAC-OS film will be described.

[0316] The CAAC-OS film is one of oxide semiconductor films having a plurality of crystal parts aligned along the c-axis.

[0317] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a crystalline microscope, clear boundaries between the crystals, i.e., crystal boundaries, are clearly visible. 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.

[0318] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). ) It can be confirmed that the metal atoms are arranged in layers in the crystalline part. Each layer has a surface on which the CAAC-OS film is formed (also referred to as a surface on which the CAAC-OS film is formed) or an uneven surface on which the CAAC-OS film is formed. The shape reflects this and is aligned parallel to the surface on which the CAAC-OS film is formed or the top surface.

[0319] On the other hand, the CAAC-OS film was observed by TEM from a direction approximately perpendicular to the sample surface (planar TEM). When observed, it was found that the metal atoms were arranged in triangular or hexagonal shapes in the crystals. However, there is no regularity in the arrangement of metal atoms between different crystal parts. stomach.

[0320] FIG. 20(a) is a cross-sectional TEM image of the CAAC-OS film. This is a cross-sectional TEM image of (a) magnified further, with the atomic arrangement emphasized for easier understanding. It is displayed.

[0321] Figure 20(c) shows the area surrounded by a circle (diameter approximately 4n) between AO and A' in Figure 20(a). m). From Fig. 20(c), it is clear that the c-axis orientation is In addition, the orientation of the c-axis is different between A-O and O-A', so different gradients are observed. In addition, the c-axis angles between the A and A crystals are 14.3° and 16.6°. 26.4°, and so on. Between these, the c-axis angle gradually changes continuously from -18.3° to -17.6° to -15.9°. It is clear that this is becoming more and more common.

[0322] When electron diffraction is performed on the CAAC-OS film, spots (bright spots) indicating orientation are observed. For example, a potential difference of 1 nm to 30 nm is measured on the top surface of the CAAC-OS film. When electron diffraction using a sagittal beam (also called nanobeam electron diffraction) is performed, spots are observed. (See FIG. 21(A)).

[0323] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It turns out that there are.

[0324] Most of the crystals in the CAAC-OS film are cubes with sides of less than 100 nm. Therefore, the crystal part included in the CAAC-OS film has a side length of 10n This also includes cases where the size fits within a cube of less than 100 mm, less than 5 nm, or less than 3 nm. In addition, multiple crystals in the CAAC-OS film are connected to form a single large crystal region. For example, in a planar TEM image, 2 Over 5μm 2 or more than 1000μm 2 Crystal regions with more than this size may be observed.

[0325] X-ray diffraction (XRD) was performed on the CAAC-OS film. For example, a CAAC-OS film with InGaZnO4 crystals was found by structural analysis using the device. 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. This indicates 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. It can be seen that it is oriented in a substantially vertical direction.

[0326] On the other hand, in-pl X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In the analysis by the ane method, a peak may appear at 2θ around 56°. This is attributed to the (110) plane of the InGaZnO4 crystal. 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 In contrast, in the case of the CAAC-OS film, 2θ is set to 5 Even when the φ is fixed at around 6° and scanned, no clear peak appears.

[0327] From the above, it is concluded that the a-axis and b-axis orientations are inconsistent between different crystal regions in the CAAC-OS film. Although it is regular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface to be formed or the upper surface. Therefore, the layered arrangement confirmed by the cross-sectional TEM observation mentioned above is consistent with the above. Each layer of aligned metal atoms is a plane parallel to the ab plane of the crystal.

[0328] The crystalline part 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 with the surface on which the CAAC-OS film is formed or the surface on which the CAAC-OS film is formed. The orientation of the CAAC-OS film is parallel to the normal vector of the top surface. When the shape is changed by etching, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed. Or it may not be parallel to the normal vector of the upper surface.

[0329] Furthermore, the distribution of c-axis oriented crystal parts in the CAAC-OS film does not need to be uniform. For example, the crystalline part of the CAAC-OS film is formed by crystal growth from the vicinity of the top surface of the CAAC-OS film. When the crystal is formed by this method, the region near the top surface has a larger amount of c-axis oriented crystals than the region near the surface on which the crystal is formed. In addition, the CAAC-OS film containing impurities may have a high ratio of The added region is transformed, forming regions with different proportions of c-axis oriented crystals. This sometimes happens.

[0330] 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 around 31°, a peak also appeared at 2θ around 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in part of the CAAC-OS film. The CAAC-OS film contains crystals that do not have a 2θ of around 31°. It is preferable that the peak is exhibited at 2θ of around 36° and that the peak is not exhibited at 2θ of around 36°.

[0331] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. These are elements 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 constitute the oxide semiconductor film, such as fluorine, 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 (or molecular radius) is large, and when it is contained inside the oxide semiconductor film, The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement and cause a decrease in crystallinity. Objects can act as carrier traps or carrier sources.

[0332] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in the semiconductor film can become carrier traps or trap hydrogen, It can be a source of carrier generation.

[0333] Low impurity concentration and low defect level density (low oxygen vacancies) are called high purity intrinsic or The term "substantially highly purified intrinsic" refers to a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film. Since there are fewer carrier generation sources, the carrier density can be reduced. A transistor using an oxide semiconductor film has electrical characteristics such as a negative threshold voltage ( It is also called marion.) It is rare for it to become high purity genuine or substantially high purity genuine. The oxide semiconductor film has few carrier traps. A transistor using such a material has little fluctuation in electrical characteristics and is highly reliable. Note that it takes a long time for charges trapped in the carrier traps in the oxide semiconductor film to be released. The time between the charges is long and the charge may behave as if it is a fixed charge. However, a transistor using an oxide semiconductor film with a high density of defect states has unstable electrical characteristics. There are cases where this happens.

[0334] In addition, transistors using CAAC-OS films show improved electrical characteristics when irradiated with visible light or ultraviolet light. The fluctuation is small.

[0335] Next, a microcrystalline oxide semiconductor film will be described.

[0336] In the microcrystalline oxide semiconductor film, crystal parts can be clearly seen in the TEM image. The crystal part contained in the microcrystalline oxide semiconductor film may have a size of 1 nm or more and 100 nm or less. , or 1 nm to 10 nm in size. Nanocrystals (nc) are microcrystals of 1 nm or less and 3 nm or less. The oxide semiconductor film having nc-OS (nanocrystalline Oxide Semiconductor Film) The nc-OS film is called a TE film. In the M observation image, the grain boundaries may not be clearly visible.

[0337] 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 nc-OS film has a periodic atomic arrangement 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 throughout the film. Therefore, depending on the analytical method, the nc-OS film may be indistinguishable from an amorphous oxide semiconductor film. For example, an XRD apparatus using X-rays with a diameter larger than that of the crystals is used for nc-OS films. When structural analysis is performed using the out-of-plane method, the crystal plane is shown. In addition, the probe diameter ( For example, electron diffraction (also called selected area electron diffraction) is performed using an electron beam of 50 nm or more. On the other hand, for the nc-OS film, Nanobeam electron diffraction using an electron beam with a probe diameter close to or smaller than the size of the crystal part Furthermore, nanobeam electron diffraction was performed on the nc-OS film. When the nc When nanobeam electron diffraction was performed on the -OS film, multiple spots were observed within the ring-shaped region. This may be the case (see Figure 21(B)).

[0338] The nc-OS film is an oxide semiconductor film with 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 defect state density than the CAAC-OS film.

[0339] 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 be a laminated film having two or more kinds of films.

[0340] When an oxide semiconductor film has multiple structures, the structure can be analyzed using nanobeam electron diffraction. may be possible.

[0341] FIG. 21C shows an electron gun chamber 70, an optical system 72 below the electron gun chamber 70, and a a sample chamber 74, an optical system 76 below the sample chamber 74, an observation chamber 80 below the optical system 76, and an observation chamber a transmission electron microscope having a camera 78 mounted at 80 and a film chamber 82 below the observation chamber 80; The diffraction measurement device is shown. The camera 78 is installed facing the inside of the observation chamber 80. The arm chamber 82 may not be provided.

[0342] FIG. 21(D) shows the internal structure of the transmission electron diffraction measurement device shown in FIG. 21(C). Inside the transmission electron diffraction measurement device, electrons emitted from an electron gun installed in the electron gun chamber 70 The light is irradiated onto a substance 88 placed in the sample chamber 74 via the optical system 72. The electrons are incident on a fluorescent screen 92 installed inside the observation chamber 80 via the optical system 76. On the plate 92, a pattern corresponding to the intensity of the incident electrons appears, forming a transmission electron diffraction pattern. can be measured.

[0343] The camera 78 is installed facing the fluorescent screen 92 and captures the pattern that appears on the fluorescent screen 92. A straight line passing through the center of the lens of the camera 78 and the center of the fluorescent screen 92 and the upper surface of the fluorescent screen 92 of the camera 78, the angle between them is, for example, 15 degrees or more and 80 degrees or less. The angle should be between 30° and 75°, or between 45° and 70°. The smaller the angle, the easier it is for the camera to The transmission electron diffraction pattern taken by the laser 78 is highly distorted. If the degree of diffraction is known, it is possible to correct distortions in the resulting transmission electron diffraction pattern. In some cases, the camera 78 may be installed in the film chamber 82. For example, 78 may be installed in the film chamber 82 so as to face the direction of incidence of the electrons 84. In this case, a transmission electron diffraction pattern with little distortion can be photographed from the rear surface of the fluorescent screen 92.

[0344] A holder for fixing a substance 88, which is a sample, is installed in the sample chamber 74. The holder is configured to be transparent to electrons passing through the material 88. The holder may have a function to move 88 along the X-axis, Y-axis, Z-axis, etc. For example, 1 nm or more and 10 nm or less, 5 nm or more and 50 nm or less, 10 nm or more and 100 nm Move within the range of 50 nm to 500 nm, 100 nm to 1 μm, etc. These ranges can be set optimally depending on the structure of the substance 88. good.

[0345] Next, the transmission electron diffraction pattern of the substance is measured using the above-mentioned transmission electron diffraction measurement device. The method will be explained.

[0346] For example, as shown in FIG. 21(D), the irradiation position of the electron 84, which is a nanobeam, in the material is By changing (scanning) the material, we can see how the structure of the material changes. In this case, if the substance 88 is a CAAC-OS film, the circuit shown in FIG. Alternatively, if the material 88 is an nc-OS film, a fold pattern is observed as shown in FIG. A diffraction pattern similar to the one shown in the figure is observed.

[0347] By the way, even if the material 88 is a CAAC-OS film, it may be partially composed of an nc-OS film or the like. Therefore, the quality of the CAAC-OS film can be determined by The ratio of the area where the diffraction pattern of the CAAC-OS film is observed in a certain range (CAAC For example, in the case of a high-quality CAAC-OS film, If so, the CAAC ratio is 50% or more, preferably 80% or more, and more preferably 90% or more. The diffraction pattern is different from that of the CAAC-OS film. The proportion of the observed area is referred to as the non-CAAC rate.

[0348] As an example, immediately after film formation (denoted as as-sputtered), or in an oxygen-containing atmosphere The top surface of each sample with the CAAC-OS film after the 450°C heat treatment was scanned. Transmission electron diffraction patterns were obtained while scanning at a speed of 5 nm / sec for 60 sec. The diffraction pattern was observed while scanning, and the observed diffraction pattern was captured as a still image every 0.5 seconds. The CAAC conversion rate was calculated by converting the electron beam. The same measurement was carried out on six samples. The average value of six samples was used for calculation.

[0349] The CAAC ratio of each sample is shown in Figure 22(A). The AC conversion rate was 75.7% (non-CAAC conversion rate was 24.3%). The CAAC content of the treated CAAC-OS film was 85.3% (non-CAAC content was 14.7%). It can be seen that the CAAC conversion rate is higher after heat treatment at 450°C than immediately after film formation. That is, the non-CAAC rate is low due to heat treatment at high temperatures (for example, 400°C or higher). In addition, in the case of heat treatment below 500°C, It can be seen that a CAAC-OS film with a high CAAC content can be obtained.

[0350] Here, most of the diffraction patterns different from those of the CAAC-OS film are similar to those of the nc-OS film. In addition, the amorphous oxide semiconductor film was not observed in the measurement area. Therefore, it is possible that a region with a structure similar to that of the nc-OS film was formed by the heat treatment. It is suggested that the CAAC domain is rearranged and formed under the influence of the structure of the adjacent domain.

[0351] 22(B) and 22(C) show the CAAC-O film immediately after deposition and after heat treatment at 450°C. 22(B) and 22(C) are planar TEM images of the S film. It can be seen that the CAAC-OS film after the heat treatment at 0°C has a more uniform film quality. It can be seen that the film quality of the CAAC-OS film is improved by the heat treatment at high temperature.

[0352] By using this measurement method, it is possible to analyze the structure of oxide semiconductor films with multiple structures. This may occur.

[0353] <Film formation model> The following describes the film formation models for CAAC-OS and nc-OS.

[0354] FIG. 46(A) shows how a CAAC-OS film is formed by sputtering. FIG.

[0355] The target 130 is adhered onto a backing plate. A plurality of magnets are arranged under the backing plate. A magnetic field is generated above the target 130. The film deposition rate is controlled by using the magnetic field of the magnet. The preferred sputtering method is called magnetron sputtering.

[0356] The target 130 has a polycrystalline structure, and each crystal grain includes a cleavage plane. The cleavage plane will be described in detail later.

[0357] The substrate 120 is disposed so as to face the target 130, and the distance therebetween is d (target The distance between the slot and the substrate (also called the distance between the slots) is 0.01 m or more and 1 m or less, preferably The thickness should be between 0.02m and 0.5m. Most of the gas in the deposition chamber is deposition gas (e.g., oxygen, Argon or a mixed gas containing 50% or more by volume of oxygen) and 0.01P The pressure is controlled to be a or more and 100 Pa or less, preferably 0.1 Pa or more and 10 Pa or less. By applying a voltage above a certain level to the target 130, discharge begins and plasma is confirmed. A high density plasma region is formed by the magnetic field above the target 130. In the high density plasma region, the deposition gas is ionized to generate ions 101. 101 is, for example, an oxygen cation (O + ) and argon cations (Ar+ ) etc. .

[0358] The ions 101 are accelerated toward the target 130 by the electric field, and eventually reach the target 130 At this time, pellets, which are sputtered particles in the form of plates or pellets, are ejected from the cleavage plane. The pellets 100a and 100b are separated and knocked out. The pellet 100b may be distorted in structure due to the impact of the ions 101. be.

[0359] The pellet 100a is a flat or pellet-shaped pellet having a triangular, for example, equilateral triangular, plane. The pellet 100b has a hexagonal, for example, regular hexagonal, plane. The sputtered particles are in the form of a plate or pellet. The flat or pellet-shaped sputter particles such as 00b are collectively called pellets 100. The planar shape of the ret 100 is not limited to a triangle or a hexagon. For example, the planar shape may be a triangle or a hexagon. There are cases where the top six or less pieces are joined together. For example, two triangles (equilateral triangles) are joined together. It may also be a square (diamond).

[0360] The thickness of the pellet 100 is determined depending on the type of deposition gas. It is preferable that the thickness of the sheet 100 is uniform. A chevron shape is preferable to a thick cubic shape.

[0361] The pellet 100 receives an electric charge as it passes through the plasma, causing the sides to become negative or positive. The pellet 100 has oxygen atoms on the side, and the oxygen atoms are negatively charged. For example, if the pellet 100a has negatively charged oxygen atoms on the side, An example of this is shown in Figure 48. In this way, the sides are charged with the same polarity, and the charges This causes repulsion and allows the CAAC-OS to maintain its flat shape. In the case of In-Ga-Zn oxide, the oxygen atoms bonded to the indium atoms are negatively charged. Or, an oxygen atom bonded to an indium atom, a gallium atom, or a zinc atom. may become negatively charged.

[0362] As shown in FIG. 46(A), for example, a pellet 100 flies like a kite through the plasma. The pellet 100 flutters up onto the substrate 120. Therefore, when an area where other pellets 100 have already accumulated approaches, a repulsive force is generated. On the upper surface of the substrate 120, a magnetic field is generated in a direction parallel to the upper surface of the substrate 120. Since a potential difference is applied between the substrate 120 and the target 130, the target Therefore, the pellet 100 is directed to the substrate 120. The upper surface of the magnet is subjected to a force (Lorentz force) due to the action of the magnetic field and the electric current (Figure 49 (See reference.) This can be understood by Fleming's left-hand rule. In order to increase the force applied to the substrate 120, A parallel magnetic field of 10 G or more, preferably 20 G or more, more preferably 30 G or more, More preferably, a region where the voltage is 50 G or more is provided. The magnetic field parallel to the upper surface of the substrate 120 is one of the magnetic fields perpendicular to the upper surface of the substrate 120. 0.5 times or more, preferably 2 times or more, more preferably 3 times or more, and even more preferably 5 times or more It is advisable to set up an area where

[0363] In addition, the substrate 120 is heated, and resistance such as friction between the pellet 100 and the substrate 120 is reduced. As a result, as shown in FIG. 50(A), the pellet 100 The pellet 100 glides over the top surface of the substrate 120. This occurs when the particles are directed toward 120°. After that, as shown in Figure 50(B), the particles that have already accumulated When the particles reach the side of the pellet 100, the sides join together. The oxygen atom on the side of 00 is released. The released oxygen atom causes the Since oxygen vacancies may be filled, a CAAC-OS with a low density of defect states is obtained.

[0364] Furthermore, when the pellet 100 is heated on the substrate 120, the atoms are rearranged and the ions are The distortion of the structure caused by the collision of the pellet 101 is relaxed. The pellets 100 become almost single crystals. Even if the pellet 100 is heated after being bonded, it is unlikely that the pellet 100 itself will expand or contract. Therefore, the gaps between the pellets 100 widen, forming defects such as grain boundaries, and cracks occur. In addition, the gaps are filled with elastic metal atoms, It is thought that the sides of the 100 misaligned pellets are connected like a highway.

[0365] According to the above model, it is considered that the pellet 100 accumulates on the substrate 120. Therefore, unlike epitaxial growth, when the surface to be formed does not have a crystalline structure, For example, it is possible to form a CAAC-OS film on the upper surface ( It is possible to form a CAAC-OS film even if the surface on which it is formed is amorphous. .

[0366] In addition, the CAAC-OS is not only applied to a flat surface, but also to the upper surface of the substrate 120, which is the surface on which the CAAC-OS is to be formed. Even if the surface has irregularities, the pellets 100 are arranged along the irregularities. For example, if the top surface of the substrate 120 is flat at the atomic level, the pellet 100 will be formed on a plane parallel to the ab plane. The flat surface is placed facing downwards, resulting in a layer with uniform thickness, flatness, and high crystallinity. Then, by stacking these layers n times (n is a natural number), CAAC-O S can be obtained (see Figure 46(B)).

[0367] On the other hand, even if the upper surface of the substrate 120 has irregularities, the CAAC-OS allows the pellet 100 to The structure is such that layers arranged side by side along the convex surface are stacked in n stages (n is a natural number). Due to the unevenness, gaps may easily occur between the pellets 100 in the CAAC-OS. However, intermolecular forces act between the pellets 100, and even if there are irregularities, there will be no gaps between the pellets. Therefore, CAA with high crystallinity is obtained even if there are irregularities. It can be C-OS (see Figure 46(C)).

[0368] Therefore, CAAC-OS does not require laser crystallization and can be used on large-area glass substrates. Even if there is a problem, uniform film formation is possible.

[0369] Since the CAAC-OS film is formed using this model, the sputtered particles have a small thickness. It is preferable that the sputtered particles are in the form of pellets. However, the surface facing the substrate 120 may not be uniform, and the thickness and crystal orientation may not be uniform. do.

[0370] The film formation model shown above allows for the formation of highly crystalline films even on a surface with an amorphous structure. A CAAC-OS having the formula:

[0371] In addition, CAAC-OS was also developed using a coating model containing zinc oxide particles in addition to pellet 100. This can also be explained as follows.

[0372] The zinc oxide particles have a smaller mass than the pellets 100 and therefore reach the substrate 120 first. On the upper surface of the substrate 120, zinc oxide particles grow preferentially in the horizontal direction to form a thin film. The zinc oxide layer has a c-axis orientation. The c-axis of the crystal is oriented parallel to the normal vector of the substrate 120. It acts as a seed layer for growing C-OS, and improves the crystallinity of CAAC-OS. The zinc oxide layer has a thickness of 0.1 nm to 5 nm, and The zinc oxide layer is thin enough that the grain boundaries are barely visible. It is not possible.

[0373] Therefore, to form a highly crystalline CAAC-OS film, a higher than stoichiometric composition is required. It is preferable to use a target containing a small proportion of zinc.

[0374] Similarly, the nc-OS can be understood by the film formation model shown in Figure 47. The only difference between FIG. 47 and FIG. 46(A) is whether or not the substrate 120 is heated.

[0375] Therefore, the substrate 120 is not heated and there is no friction between the pellet 100 and the substrate 120. As a result, the pellet 100 is in a state of high resistance. Since it cannot glide, it accumulates irregularly and You can get the OS.

[0376] <cleavage plane> Below, we explain the cleavage plane of the target described in the CAAC-OS film formation model. do.

[0377] First, the cleavage plane of the target will be explained using FIG. 51. The crystal structure of O4 is shown in Figure 51(A). The c-axis is oriented upward and parallel to the b-axis. The structure of the InGaZnO4 crystal is shown when observed from the c-axis. The figure shows the structure of an InGaZnO4 crystal when observed from a direction parallel to the plane.

[0378] The energy required for cleavage on each crystal plane of an InGaZnO4 crystal was calculated using first-principles calculations. The calculation is performed using a pseudopotential and a density functional process using a plane wave basis. The pseudopotential used is an ultra-soft pseudopotential (CASTEP). The functional is GGA PBE. The energy is set to 400 eV.

[0379] The energy of the structure in the initial state is derived after structural optimization including the cell size. In addition, the energy of the structure after cleavage on each plane is calculated by the atomic arrangement with the cell size fixed. It is derived after structural optimization of the position.

[0380] Based on the crystal structure of InGaZnO4 shown in Figure 51, the first, second, and third planes A structure cleaved at either of the fourth planes was fabricated, and structural optimization calculations were performed with the cell size fixed. Here, the first plane is a crystal plane between the Ga-Zn-O layer and the In-O layer, and (0 The second plane is a crystal plane parallel to the α-plane (or ab-plane) (see Figure 51(A)). The crystal plane between the Ga-Zn-O layers is the (001) plane (or ab The third plane is a crystal plane parallel to the (110) plane (see Figure 51(A)). The fourth plane is a crystal plane (see Figure 51(B)). It is a straight crystal plane (see Figure 51(B)).

[0381] Under the above conditions, the energy of the structure after cleavage on each plane is calculated. The difference between the energy of the structure and the energy of the initial state is divided by the area of ​​the cleavage plane. The cleavage energy, which is a measure of the ease of cleavage on each plane, is calculated. Energy is the kinetic energy of the electrons and the interatomic and atomic energies of the atoms and electrons contained in the structure. -This is the energy that takes into account the interactions between electrons and electrons themselves.

[0382] As a result of calculations, the cleavage energy of the first facet is 2.60 J / m 2 , the cleavage energy of the second face is 0.68J / m 2 , the cleavage energy of the third face is 2.18 J / m 2 , 4th plane cleavage Energy is 2.12J / m 2 It was found that (see table below).

[0383] [Table 1]

[0384] From this calculation, in the crystal structure of InGaZnO4 shown in Figure 51, The cleavage energy is lowest between the Ga-Zn-O layer and the Ga-Zn-O layer. is the plane (cleavage plane) that is easiest to cleave. When referring to the cleavage plane, it refers to the second plane, which is the plane that is easiest to cleave.

[0385] Since the cleavage plane is on the second plane between the Ga-Zn-O layers, the structure shown in FIG. 5 The InGaZnO4 crystal shown in 1(A) can be separated into two planes equivalent to the second plane. Therefore, when ions or the like are bombarded with the target, the highest cleavage energy is The minimum size is a wafer-like unit (we call it a pellet) cleaved along the lower plane of the In this case, the InGaZnO4 pellets are It consists of three layers: a Ga-Zn-O layer, an In-O layer, and a Ga-Zn-O layer.

[0386] The first plane (a crystal plane between the Ga-Zn-O layer and the In-O layer, which is the (001) plane ( The third plane (crystal plane parallel to the (110) plane) and the fourth plane (crystal plane parallel to the (110) plane) are more closely spaced than the ab plane. Since the cleavage energy of the plane (crystal plane parallel to the (100) plane (or bc plane)) is low, This suggests that the planar shape of the pellets is often triangular or hexagonal.

[0387] Next, classical molecular dynamics calculations were performed to identify the target InGaZ Assuming a crystal of nO4, the target is spat out with argon (Ar) or oxygen (O). The cleavage plane of the InGaZnO4 crystal (268 8 atoms) is shown in Fig. 52(A) and the top view structure is shown in Fig. 52(B). The fixed layer shown in A) is a layer in which the atomic arrangement is fixed so that the position does not fluctuate. The temperature control layer shown in 2(A) is a layer that is always kept at a constant temperature (300K).

[0388] For classical molecular dynamics calculations, Fujitsu Materials Explorer 5. 0 is used. The initial temperature is 300K, the cell size is constant, and the time step width is 0.01 The calculation assumes that the atom is subjected to 300e V energy is applied, and atoms are introduced into the cell from a direction perpendicular to the ab plane of the InGaZnO4 crystal. Let it enter.

[0389] FIG. 53(A) shows the state where argon is incident on the cell having the InGaZnO4 crystal shown in FIG. Figure 53(B) shows the atomic arrangement 99.9 picoseconds (psec) after the cell The atomic arrangement is shown in Figure 53, 99.9 picoseconds after oxygen is incident on the A part of the fixed layer shown in A) is omitted.

[0390] From Figure 53(A), within 99.9 picoseconds after argon entered the cell, Therefore, cracks occur from the cleavage plane corresponding to the second plane shown in Fig. 1. When argon collides with the crystal, the top surface is the second surface (0th), and the second surface (2 It can be seen that large cracks occur in the first (second) crack.

[0391] On the other hand, from Figure 53(B), it can be seen that within 99.9 picoseconds after oxygen enters the cell, the ) and the cracks start from the cleavage plane corresponding to the second plane shown in Fig. 1. When the collision occurs, a large crack occurs on the second (first) surface of the InGaZnO4 crystal. It can be seen that...

[0392] Therefore, from the top surface of the target containing InGaZnO4 crystals with a homologous structure When atoms (ions) collide with the InGaZnO4 crystal, the InGaZnO4 crystal cleaves along the second plane, forming a flat surface. It can be seen that plate-shaped particles (pellets) peel off. At this time, the size of the pellets is It was found that the collision with oxygen was smaller than that with argon. do.

[0393] The above calculations suggest that the detached pellet contains a damaged area. The damaged area contained in the nucleus can be repaired by reacting oxygen with the defects caused by the damage. There is a match.

[0394] Therefore, we investigated whether the pellet size differs depending on the atom that is collided. do.

[0395] In FIG. 54(A), argon is incident on the cell having the InGaZnO4 crystal shown in FIG. After this, the trajectories of each atom are shown from 0 ps to 0.3 ps. 4(A) corresponds to the period between FIG. 52 and FIG. 53(A).

[0396] From Figure 54(A), it can be seen that argon collides with gallium (Ga) in the first layer (Ga-Zn-O layer). When the gallium collides with zinc (Zn) in the third layer (Ga-Zn-O layer), the zinc It can be seen that lead reaches the vicinity of the sixth layer (Ga-Zn-O layer). The argon that hits the substrate is repelled outwards. When argon is bombarded onto the target, a crack appears on the second surface (2nd) in Figure 52(A). It is thought that this will be included.

[0397] Also, in FIG. 54(B), oxygen enters the cell having the InGaZnO4 crystal shown in FIG. The trajectory of each atom is shown from 0 picoseconds to 0.3 picoseconds after irradiation. 54(B) corresponds to the period between FIG. 52 and FIG. 53(A).

[0398] On the other hand, as shown in Figure 54(B), oxygen collides with gallium (Ga) in the first layer (Ga-Zn-O layer). Then, after the gallium collides with the zinc (Zn) in the third layer (Ga-Zn-O layer), It can be seen that zinc does not reach the fifth layer (In-O layer). Therefore, the target containing InGaZnO4 crystals is When the element is collided, it is thought that a crack will appear on the second surface (first surface) in Figure 52(A). do.

[0399] From this calculation, it can be seen that when atoms (ions) collide with InGaZnO4 crystals, It is suggested that peeling occurs.

[0400] In addition, we will consider the difference in crack depth from the viewpoint of conservation laws. The existence law can be expressed as equations (1) and (2), where E is the The energy of gon or oxygen (300 eV), m A is the mass of argon or oxygen, v A is the velocity of argon or oxygen before the collision, v' A is the velocity of argon or oxygen after the collision, m Ga is the mass of gallium, v Ga is the velocity of gallium before the collision, v' GaGalliu after the collision is the speed of the

[0401]

number

[0402]

number

[0403] Assuming that the collisions of argon or oxygen are elastic, v A , v' A , v Ga and v' Ga The relationship can be expressed as equation (3).

[0404]

number

[0405] From equations (1), (2) and (3), V Ga If argon or oxygen is collided with The velocity of the gallium after impact is v' Ga can be expressed as in equation (4).

[0406]

number

[0407] In equation (4), m A Substitute the mass of argon or the mass of oxygen into Compare the velocity of gallium after the collision. The energy of argon and oxygen before the collision When the ratio is the same, the collision with argon is 1.24 times greater than the collision with oxygen. Therefore, the energy of gallium is also higher than that of Argon. When an electron collides with an electron, the velocity is higher by the square of the velocity than when an oxygen collides with an electron.

[0408] When argon is bombarded, the speed of gallium after the bombardment is higher than when oxygen is bombarded. Therefore, when argon is collided with the However, it is believed that cracks occurred at a deeper position than when oxygen was bombarded.

[0409] From the above calculations, the target containing InGaZnO4 crystals with a homologous structure was It can be seen that when sputtered, the cleaved surface peels off and a pellet is formed. Sputtering other structural areas of the target that do not have the pores does not result in pellet formation. The sputtered particles are formed at the atomic level, which is smaller than the particles. Since it is smaller than the nozzle, it can be easily evacuated via a vacuum pump connected to the sputtering system. Therefore, the crystal of InGaZnO4 with homologous structure When a target containing gallium is sputtered, particles of various sizes and shapes fly to the substrate and are deposited. It is difficult to imagine a model in which a film is formed by depositing sputtered pellets. The model shown in Figure 46(A) for forming an -OS film is reasonable.

[0410] The density of the CAAC-OS film formed in this way is comparable to that of single-crystal OS. For example, the density of a single crystal OS with a homologous structure of InGaZnO4 is 6.36 g / cm 3 In contrast, the density of CAAC-OS, which has a similar atomic ratio, is 6.3 g / cm 3 It will be about that amount.

[0411] Figure 55 shows the In-Ga-Zn oxide (CAAC-OS) film formed by sputtering. See Figure 55(A).) and the element in the cross section of its target (see Figure 55(B). The atomic arrangement is shown. High-angle scattering annular dark-field scanning transmission electron microscopy (HAA) was used to observe the atomic arrangement. DF-STEM:High-Angle Annular Dark Field Sc anning Transmission Electron Microscopy) In HAADF-STEM, the image intensity of each atom is proportional to the square of the atomic number. Therefore, Zn (atomic number 30) and Ga (atomic number 31) have similar atomic numbers. The HAADF-STEM uses a Hitachi HD-270 scanning transmission electron microscope. Use 0.

[0412] Comparing Figure 55(A) and Figure 55(B), both CAAC-OS and the target It can be seen that they have homologous structures and the arrangement of their atoms corresponds to each other. Therefore, as shown in the film formation model in Figure 46(A), the crystal structure of the target is transferred. It can be seen that a CAAC-OS film is formed by this.

[0413] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0414] (Embodiment 6) As described in Embodiment 2, a transistor including an oxide semiconductor film has a low resistance in an off state. Therefore, the current value (off-state current value) of the electric signal such as the image signal can be controlled to a low value. The retention time can be extended and the write interval can also be set longer.

[0415] In the display device of this embodiment, by using a transistor with a low off-state current, at least The display device can be configured to perform display using two driving methods (modes). The drive method is a conventional display device drive method in which data is rewritten sequentially for each frame. The second driving mode is a method in which data is rewritten after the data writing process is executed. This is a driving method that stops the refresh rate. do.

[0416] The first driving mode is used to display moving images. The second driving mode is used to display still images. Since the data remains unchanged, there is no need to rewrite the data for each frame. When displaying still images, the second driving mode can be used to eliminate screen flicker. Both can reduce power consumption.

[0417] In addition, the capacitance element of the pixel applied to the display device of this embodiment is Therefore, it is possible to extend the time for which the potential of the pixel electrode is maintained. A driving mode that reduces the refresh rate can be applied. Even when a drive mode that reduces the flash rate is applied, the voltage held by the pixel changes. This makes it possible to suppress flickering for a long period of time, thereby preventing the user from perceiving image flicker. Therefore, it is possible to reduce power consumption and improve display quality.

[0418] Here, the effect of reducing the refresh rate will be described.

[0419] There are two types of eye fatigue: nervous fatigue and muscular fatigue. Continuing to look at the light-emitting or flashing screen of a display device stimulates the retina, nerves, and brain of the eye. Muscle fatigue is caused by the ciliary muscles used to adjust focus. It is something that makes you tired by overworking your body.

[0420] FIG. 23(A) is a schematic diagram showing the display of a conventional display device. In the case of a conventional display device, the image is rewritten 60 times per second. Looking at such a screen for a long time can stimulate the retina, nerves, and brain of the user, causing eye fatigue. was likely to be caused.

[0421] In one embodiment of the present invention, a transistor with extremely low off-state current, for example, A transistor including an oxide semiconductor is used. The capacitance element can be made large in area. This suppresses charge leakage and makes it possible to make potential changes more gradual, Even if the frame frequency is lowered, the brightness of the display device can be suppressed.

[0422] That is, as shown in FIG. 23(B), for example, the image can be rewritten once every five seconds. This allows the same image to be viewed as much as possible, reducing the flickering of the screen that is visible to the user. This reduces the stimulation of the retina, nerves and brain of the user's eyes, and reduces nervous system fatigue. It will be reduced.

[0423] According to one embodiment of the present invention, a display device that is easy on the eyes can be provided.

[0424] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0425] (Embodiment 7) In this embodiment, an image for color display in a display device according to one embodiment of the present invention will be described. An example of the configuration of the element will be described with reference to the drawings. The pixel that can be used is represented as pixel pix_color, and pixel pix_color is The constituent pixels will be described as sub-pixels sub_pix. The pixel sub_pix corresponds to the pixel pix described in the second embodiment above.

[0426] 24(A) to 24(D) show the structure of the pixel pix_color that can perform color display. An example is shown below.

[0427] FIG. 24(A) shows the pixel pi when color display is performed using the three primary colors R (red), G (green), and B (blue). An example of the configuration of x_color is shown below. Each sub-pixel sub_pix has a light-emitting element. Alternatively, white light is emitted and each of the RGB colors is displayed using a color filter. A configuration for converting the color into one color or a configuration for converting into each of the RGB colors using a color conversion layer may be used. As shown in FIG. 24(A), the pixel pix_color has a sub-pixel that emits R. sub_pix_R, a sub-pixel that emits G, and a sub-pixel that emits B. The pixels sub_pix_B and sub_pix_C can be arranged in a stripe pattern.

[0428] Figure 24(B) shows a color display using the three primary colors R (red), G (green), and B (blue) plus white (W). The following shows an example of the configuration of the pixel pix_color in this case. The element is made of a material that exhibits each color, or it emits white light and displays the color filter. A filter converts colors to RGB colors, or a color conversion layer converts colors to RGBW colors. As shown in FIG. 24B, the pixel pix_color is A sub-pixel sub_pix_R that emits red light, a sub-pixel sub_pix_G that emits green light, and , a sub-pixel sub_pix_B that emits B, and a sub-pixel sub_pix_ The W-emitting sub-pixel sub_pix is ​​arranged in a stripe pattern. This eliminates the need for a color filter, thereby reducing power consumption.

[0429] Figure 24(C) shows a color display using the three primary colors R (red), G (green), and B (blue) plus yellow (Y). The following shows an example of the configuration of the pixel pix_color in this case. The element is made of a material that exhibits each color, or it emits white light and displays the color filter. A filter is used to convert the colors into RGBY colors, or a color conversion layer is used to convert the colors into RGBY colors. As shown in FIG. 24(C), the pixel pix_color has the following configuration: A sub-pixel sub_pix_R that emits R and a sub-pixel sub_pix_G that emits G a sub-pixel sub_pix_B that emits B, and a sub-pixel sub_pix_B that emits Y. _Y are arranged in a stripe pattern. In the sub-pixel sub_pix that emits Y, By simultaneously emitting the complementary color B, the sub-pixel sub_pix_B emits white light. Since two colors can be obtained, there is no need to light up RGB simultaneously. In a configuration where white is obtained by emitting light from three sub-pixels, white is obtained by emitting light from three sub-pixels, sub_pix. This configuration can reduce power consumption compared to the previous configuration.

[0430] In Figure 24(D), the three primary colors R (red), G (green), and B (blue) are combined with yellow (Y), magenta (M), and cyan. The following shows an example of the pixel pix_color configuration when adding a pixel (C) for color display. In the sub-pixel sub_pix, the light emitting element is made of a material that exhibits each color. A configuration that emits white light and converts it into each color of RGBYMC using a color filter, or A conversion layer can be used to convert the image into each color of RGBYMC. As shown in the figure, the pixel pix_color has a sub-pixel sub_pix_R that emits R, A sub-pixel sub_pix_G that emits G and a sub-pixel sub_pix_B that emits B a sub-pixel sub_pix_Y that emits Y, and a sub-pixel sub_pix_Y that emits M. _M and sub-pixels sub_pix_C that emit C can be arranged in a stripe pattern. By adopting this configuration, the color saturation can be improved.

[0431] In addition, in FIGS. 24A to 24D, the sub-pixels sub_pix corresponding to each color are, for example, However, the shape is not limited to this and may be a triangle, an ellipse, a square, or the like. The pixel pix_color can be constructed by combining the sub-pixels sub_pix.

[0432] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0433] (Embodiment 8) In this embodiment, structural examples of electronic devices to which the display device of one embodiment of the present invention is applied will be described. In addition, in this embodiment, a display module to which the display device of one embodiment of the present invention is applied will be described. This will be explained with reference to FIG.

[0434] The display module 8000 shown in FIG. 25 is made up of an upper cover 8001 and a lower cover 8002. In between, touch panel 8004 connected to FPC8003, and touch panel 8005 connected to FPC8005 Display panel 8006, backlight unit 8007, frame 8009, printed circuit board 8010 and a battery 8011. The reader 8011, the touch panel 8004, etc. may not be provided.

[0435] The display device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0436] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel 8005. The shape and dimensions can be changed appropriately to match the size of 006.

[0437] The touch panel 8004 is a resistive or capacitive touch panel. 8006. In addition, the opposing substrate (sealing substrate) of the display panel 8006 ) can also be equipped 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 panel is formed. It is also possible to use a panel.

[0438] The backlight unit 8007 includes a light source 8008. It may be provided at the end of the unit 8007 and configured to use a light diffusion plate.

[0439] The frame 8009 protects the display panel 8006 and also prevents the operation of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the frame. The frame 8009 may also function as a heat sink.

[0440] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply to the power supply circuit can be an external commercial power supply or Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0441] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0442] 26(A) to 26(H) and 27(A) to 27(D) are diagrams showing electronic devices. These electronic devices include a housing 5000, a display unit 5001, a speaker 5003, and a LE. D lamp 5004, operation key 5005 (including power switch or operation switch), connection Terminal 5006, sensor 5007 (force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance , light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, voltage, power, radiation (including functions to measure flow rate, humidity, gradient, vibration, odor or infrared rays), It can have a 5008, etc.

[0443] FIG. 26(A) shows a mobile computer, which includes, in addition to the above, a switch 5009 , an infrared port 5010, etc. FIG. 26(B) shows a portable terminal equipped with a recording medium. A portable image reproducing device (for example, a DVD reproducing device) is also included. The display unit 5002, the recording medium reading unit 5011, etc. It is a group-type display, and in addition to the above, it has a second display unit 5002, a support unit 5012 , earphones 5013, etc. FIG. 26(D) shows a portable gaming machine. In addition to the above, it may have a recording medium reading unit 5011, etc. It is a digital camera with a TV receiving function, and in addition to the above, it also has an antenna 5014, The mobile phone may have a shutter button 5015, an image receiving unit 5016, etc. It is a belt-type gaming machine, and in addition to the above, it has a second display unit 5002, a recording medium reading unit 5011, , etc. FIG. 26(G) shows a television receiver, which, in addition to the above, has It can have a tuner, an image processor, etc. FIG. 26(H) shows a portable television receiver. In addition to the above, it has a charger 5017 capable of transmitting and receiving signals, etc. FIG. 27(A) shows a display, which includes, in addition to the above, a support base 5018, FIG. 27(B) shows a camera, which has external connections in addition to the above. It may have a port 5019, a shutter button 5015, an image receiving unit 5016, etc. FIG. 27(C) shows a computer that includes, in addition to the above, a pointing device 5 020, an external connection port 5019, a reader / writer 5021, etc. FIG. 27(D) shows a mobile phone, which in addition to the above-mentioned components includes a transmitting unit, a receiving unit, a mobile phone / transmitter It may have a tuner for one segment partial reception services for mobile terminals, etc.

[0444] The electronic devices shown in FIGS. 26(A) to 26(H) and 27(A) to 27(D) can be used in various For example, various information (still images, videos, text images, etc.) can be stored. ) on the display, touch panel function, calendar, date or time display, etc. Functions for controlling processing using various software (programs), wireless communication functions , the ability to connect to various computer networks using wireless communication functions, wireless communication functions A function to send or receive various data using the program recorded on the recording medium. Or, it can have a function of reading out data and displaying it on a display unit. In electronic devices having such a display unit, one display unit is used to mainly display image information, and another display unit is used to A function that mainly displays text information on one display unit, or a function that takes parallax into account on multiple displays By displaying the image, it is possible to have a function of displaying a three-dimensional image. In electronic devices having an image receiving unit, there are functions for taking still images, taking moving images, and Function to automatically or manually correct captured images, and to save captured images to a recording medium (external or camera) It can have functions such as saving the captured image to a camera (built-in), displaying the captured image on the display, etc. In addition, the electronic devices shown in Figures 26(A) to 26(H) and Figures 27(A) to 27(D) The functions that the container can have are not limited to these, and the container can have a variety of functions.

[0445] The electronic device described in this embodiment has a display unit for displaying some information. It is characterized by the following.

[0446] Next, application examples of the display device will be described.

[0447] FIG. 27(E) shows an example in which a display device is integrated with a building. ) includes a housing 5022, a display unit 5023, a remote control device 5024 as an operation unit, and a speaker. The display device is a wall-mounted type that is integrated with the building, and the installation space is limited. It can be installed without requiring a large space.

[0448] FIG. 27(F) shows another example in which a display device is provided inside a building as an integral part of the building. The display module 5026 is attached to the unit bath 5027. The bather can then view the display module 5026.

[0449] In this embodiment, a wall and a unit bath are used as examples of buildings. The form is not limited to this, and the display device can be installed in various buildings.

[0450] Next, an example in which the display device is provided integrally with a moving object will be described.

[0451] FIG. 27(G) is a diagram showing an example in which the display device is installed in an automobile. The control unit 5028 is attached to the body 5029 of the automobile and controls the operation of the body or the inside and outside of the automobile. It is possible to display information entered from the navigation function on demand. may have

[0452] FIG. 27(H) is a diagram showing an example in which a display device is integrated into a passenger airplane. FIG. 27(H) shows a display module 503 mounted on a ceiling 5030 above the seats of a passenger airplane. 1 is provided. The display module 5031 is a diagram showing the shape of the display module when in use. The ceiling 5030 is attached to the ceiling 5030 via a hinge portion 5032. The expansion and contraction of the display module 503 allows passengers to view the display module 5031. 1 has a function of displaying information by being operated by a passenger.

[0453] In addition, in the present embodiment, examples of the moving body include an automobile body and an airplane body. However, it is not limited thereto, and it can be installed in various things such as motorcycles, four-wheeled vehicles (including automobiles, buses, etc.), trains (including monorails, railways, etc.), ships, etc.

[0454] In addition, in this specification, etc., in the figure or text described in a certain embodiment, it is possible to extract a part thereof to constitute an aspect of the invention. Therefore when a figure or text describing a certain part is described, the content obtained by extracting a part of the figure or text thereof is also disclosed as an aspect of the invention and can constitute an aspect of the invention. Therefore, for example, in a drawing or text in which a single or plural number of active elements (such as transistors, diodes, etc.), wirings, passive elements (such as capacitive elements, resistive elements, etc.), conductive layers, insulating layers, semiconductor layers, organic materials, inorganic materials, parts, devices, operation methods, manufacturing methods, etc. are described, it is possible to extract a part thereof to constitute an aspect of the invention. For example, from a circuit diagram composed of N (N is an integer) circuit elements (such as transistors, capacitive elements, etc.), it is possible to extract M (M is an integer and M < N) circuit elements (such as transistors, capacitive elements, etc.) to constitute an aspect of the invention. As another example, from a cross-sectional view composed of N (N is an integer) layers, it is possible to extract M (M is an integer and M < N) layers to constitute an aspect of the invention. As yet another example, from a flowchart composed of N (N is an integer) elements, it is possible to extract M (M is an integer and M < N elements) to constitute an aspect of the invention. For example, from a circuit diagram having N (N is an integer) circuit elements (such as transistors, capacitive elements, etc.), it is possible to extract M (M is an integer and M < N) circuit elements (such as transistors, capacitive elements, etc.) to constitute an aspect of the invention. As another example, from a cross-sectional view having N (N is an integer) layers, it is possible to extract M (M is an integer and M < N) layers to constitute an aspect of the invention. As yet another example, from a flowchart having N (N is an integer) elements, it is possible to extract M (M is an integer and M < N) elements to constitute an aspect of the invention. (N is an integer) elements to constitute an aspect of the invention. ) can be extracted to constitute one aspect of the invention.

[0455] In this specification, etc., in a drawing or text described in a certain embodiment, When at least one specific example is described, the generic concept of that specific example must be derived. This will be easily understood by those skilled in the art. If at least one specific example is described in the drawings or text, The concept is also disclosed as an aspect of the invention and may constitute an aspect of the invention. It is possible.

[0456] In this specification, at least the contents shown in the drawings (or even a part of the drawings) is disclosed as one aspect of the invention and can constitute one aspect of the invention. Therefore, if a certain content is shown in a diagram, it can be explained in writing. Even if there is no such content, the content is disclosed as one aspect of the invention, and one aspect of the invention Similarly, even if a part of the drawings is taken out, it is possible to construct the invention. and can constitute one embodiment of the invention. [Explanation of symbols]

[0457] C1 Capacitor element GL1 wiring GL2 wiring GL3 wiring EL light-emitting element IL wiring CL wiring SL wiring pix pixel M1 transistor M2 transistor M3 transistor M4 transistor M5 transistor M6 transistor t1 period t2 period t3 period t4 period Vdata potential Vano potential Vcat potential V0 potential V1 potential VL0 wiring VL1 wiring 11 Pixel section 14 Scanning line driving circuit 16 Signal line driver circuit 17 scan lines 19 Signal line 19b Pixel electrode 25 Capacitance Line 28 Substance 31 Liquid crystal element 41 Light-emitting element 43 Transistor 45 transistors 51 Gate insulating film 53 Inorganic insulating film 53a Insulating film 70 Electron Gun Room 72 Optical system 74 Sample Room 76 Optical system 78 Camera 80 Observation Room 82 Film Room 84 electronic 88 Substance 92 Fluorescent screen 102 transistor 102a transistor 102b transistor 103 Transistor 103a Transistor 103c transistor 103d Transistor 105 Capacitive element 301 pixels 302 Substrate 304a Conductive film 304b Conductive film 304c conductive film 304d conductive film 305 Insulating film 306 Insulating film 307 Oxide semiconductor film 308a Oxide semiconductor film 308b Oxide semiconductor film 308c metal oxide film 308d Oxide semiconductor film 308e Oxide semiconductor film 308f metal oxide film 309 Conductive Film 310a Conductive film 310b Conductive film 310c conductive film 310d conductive film 310e conductive film 310f conductive film 310g conductive film 310h conductive film 310i conductive film 310j conductive film 311 Insulating film 311a Insulating film 311b insulating film 312 insulating film 312a Insulating film 312b insulating film 313 Insulating Film 314 Insulating film 315 Conductive Film 316b Conductive film 316d Conductive film 316e Conductive film 317 Organic insulating film 317a Organic insulating film 318 Conductive Film 319 Conductive Film 319a Conductive film 319b Conductive film 319c conductive film 320 Alignment Film 336 Multilayer film 336a Oxide semiconductor film 336b Oxide semiconductor film 342 PCB 362 Opening 364a opening 364b opening 364c opening 391 Insulating Layer 392 luminescent layer 393 Conductive Film 394 Light-emitting elements 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared port 5011 Recording medium reading unit 5012 Support part 5013 Earphones 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 5018 Support stand 5019 External connection port 5020 pointing device 5021 Reader / Writer 5022 Housing 5023 Display section 5024 Remote control device 5025 Speaker 5026 Display Module 5027 Unit bath 5028 Display Module 5029 Car Body 5030 Ceiling 5031 Display Module 5032 Hinge part 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. Each pixel comprises a first to third transistor, a capacitive element, a light-emitting element, a signal line whose potential is controlled by a signal line driving circuit, and a first wiring. The second transistor has the function of controlling the current supplied to the light-emitting element in accordance with the potential supplied to the second transistor, at least via the signal line and the first transistor. Either the source electrode or the drain electrode of the third transistor is electrically connected to the first wiring. The source electrode or drain electrode of the third transistor, the other of which is electrically connected to the pixel electrode of the light-emitting element, One electrode of the capacitive element is electrically connected to either the source electrode or the drain electrode of the first transistor. The other electrode of the capacitive element is a light-emitting device electrically connected to the pixel electrode, A first conductive film having a region positioned above the insulating surface and functioning as the gate electrode of the second transistor, A first insulating film having a region positioned above the first conductive film, An oxide semiconductor film having a region positioned above the first insulating film and having a channel formation region for the second transistor, A second conductive film having a region positioned above the first insulating film and functioning as the other electrode of the capacitive element, A third conductive film having a region positioned above the oxide semiconductor film and functioning as either the source electrode or the drain electrode of the second transistor, A fourth conductive film having a region positioned above the oxide semiconductor film and functioning as the other of the source electrode or drain electrode of the second transistor, A fifth conductive film having a region positioned above the second conductive film and electrically connected to the second conductive film, A second insulating film having a region positioned above the second conductive film, a region positioned above the third conductive film, a region positioned above the fourth conductive film, and a region positioned above the fifth conductive film, A sixth conductive film having a region positioned above the second insulating film and functioning as the pixel electrode, A partition wall having a region positioned above the sixth conductive film, The second conductive film has a region that does not overlap with the fifth conductive film. The conductive film 6 above is electrically connected to the conductive film 5 above. Light-emitting device.

2. Each pixel comprises a first to third transistor, a capacitive element, a light-emitting element, a signal line whose potential is controlled by a signal line driving circuit, and a first wiring. The second transistor has the function of controlling the current supplied to the light-emitting element in accordance with the potential supplied to the second transistor, at least via the signal line and the first transistor. Either the source electrode or the drain electrode of the third transistor is electrically connected to the first wiring. The source electrode or drain electrode of the third transistor, the other of which is electrically connected to the pixel electrode of the light-emitting element, One electrode of the capacitive element is electrically connected to either the source electrode or the drain electrode of the first transistor. The other electrode of the capacitive element is a light-emitting device electrically connected to the pixel electrode, A first conductive film having a region positioned above the insulating surface and functioning as the gate electrode of the second transistor, A first insulating film having a region positioned above the first conductive film, An oxide semiconductor film having a region positioned above the first insulating film and having a channel formation region for the second transistor, A second conductive film having a region positioned above the first insulating film and functioning as the other electrode of the capacitive element, A third conductive film having a region positioned above the oxide semiconductor film and functioning as either the source electrode or the drain electrode of the second transistor, A fourth conductive film having a region positioned above the oxide semiconductor film and functioning as the other of the source electrode or drain electrode of the second transistor, A fifth conductive film having a region positioned above the second conductive film and electrically connected to the second conductive film, A second insulating film having a region positioned above the second conductive film, a region positioned above the third conductive film, a region positioned above the fourth conductive film, and a region positioned above the fifth conductive film, A sixth conductive film having a region positioned above the second insulating film and functioning as the pixel electrode, A partition wall having a region positioned above the sixth conductive film, The second insulating film has a region in contact with the upper surface of the third conductive film, a region in contact with the upper surface of the fourth conductive film, and a region in contact with the upper surface of the fifth conductive film. The second conductive film has a region that does not overlap with the fifth conductive film. The conductive film 6 above is electrically connected to the conductive film 5 above. Light-emitting device.

3. Each pixel comprises a first to third transistor, a capacitive element, a light-emitting element, a signal line whose potential is controlled by a signal line driving circuit, and a first wiring. The second transistor has the function of controlling the current supplied to the light-emitting element in accordance with the potential supplied to the second transistor, at least via the signal line and the first transistor. Either the source electrode or the drain electrode of the third transistor is electrically connected to the first wiring. The source electrode or drain electrode of the third transistor, the other of which is electrically connected to the pixel electrode of the light-emitting element, One electrode of the capacitive element is electrically connected to either the source electrode or the drain electrode of the first transistor. The other electrode of the capacitive element is a light-emitting device electrically connected to the pixel electrode, A first conductive film having a region positioned above the insulating surface and functioning as the gate electrode of the second transistor, A first insulating film having a region positioned above the first conductive film, An oxide semiconductor film having a region positioned above the first insulating film and having a channel formation region for the second transistor, A second conductive film having a region positioned above the first insulating film and functioning as the other electrode of the capacitive element, A third conductive film having a region positioned above the oxide semiconductor film and functioning as either the source electrode or the drain electrode of the second transistor, A fourth conductive film having a region positioned above the oxide semiconductor film and functioning as the other of the source electrode or drain electrode of the second transistor, A fifth conductive film having a region positioned above the second conductive film and a region in contact with the second conductive film, A second insulating film having a region positioned above the second conductive film, a region positioned above the third conductive film, a region positioned above the fourth conductive film, and a region positioned above the fifth conductive film, A sixth conductive film having a region positioned above the second insulating film and functioning as the pixel electrode, A partition wall having a region positioned above the sixth conductive film, The second conductive film has a region that does not overlap with the fifth conductive film. The conductive film 6 above is electrically connected to the conductive film 5 above. Light-emitting device.

4. Each pixel comprises a first to third transistor, a capacitive element, a light-emitting element, a signal line whose potential is controlled by a signal line driving circuit, and a first wiring. The second transistor has the function of controlling the current supplied to the light-emitting element in accordance with the potential supplied to the second transistor, at least via the signal line and the first transistor. Either the source electrode or the drain electrode of the third transistor is electrically connected to the first wiring. The source electrode or drain electrode of the third transistor, the other of which is electrically connected to the pixel electrode of the light-emitting element, One electrode of the capacitive element is electrically connected to either the source electrode or the drain electrode of the first transistor. The other electrode of the capacitive element is a light-emitting device electrically connected to the pixel electrode, A first conductive film having a region positioned above the insulating surface and functioning as the gate electrode of the second transistor, A first insulating film having a region positioned above the first conductive film, An oxide semiconductor film having a region positioned above the first insulating film and having a channel formation region for the second transistor, A second conductive film having a region positioned above the first insulating film and functioning as the other electrode of the capacitive element, A third conductive film having a region positioned above the oxide semiconductor film and functioning as either the source electrode or the drain electrode of the second transistor, A fourth conductive film having a region positioned above the oxide semiconductor film and functioning as the other of the source electrode or drain electrode of the second transistor, A fifth conductive film having a region positioned above the second conductive film and a region in contact with the second conductive film, A second insulating film having a region positioned above the second conductive film, a region positioned above the third conductive film, a region positioned above the fourth conductive film, and a region positioned above the fifth conductive film, A sixth conductive film having a region positioned above the second insulating film and functioning as the pixel electrode, A partition wall having a region positioned above the sixth conductive film, The second insulating film has a region in contact with the upper surface of the third conductive film, a region in contact with the upper surface of the fourth conductive film, and a region in contact with the upper surface of the fifth conductive film. The second conductive film has a region that does not overlap with the fifth conductive film. The conductive film 6 above is electrically connected to the conductive film 5 above. Light-emitting device.

5. In any one of claims 1 to 4, The fifth conductive film has a plurality of laminated conductive films. Light-emitting device.

Images