Indication device

Abstract

To provide a display device with excellent display quality. [Solution] A transistor on a substrate, an inorganic insulating film in contact with the transistor, and an inorganic insulating film An organic insulating film in contact with the transistor, a capacitive element electrically connected to the transistor, and a shape formed on the organic insulating film. A display device having pixel electrodes that are made and electrically connected to transistors. A transistor consists of a gate electrode on a substrate, an oxide semiconductor film overlapping the gate electrode, and an oxide semiconductor film. A gate insulating film in contact with one side of the conductive film, and a pair of conductive films in contact with the oxide semiconductor film, It has. The capacitive element has a metal oxide film on the gate insulating film, an inorganic insulating film, and on the inorganic insulating film The pixel electrode has a first light-transmitting conductive film and a second light-transmitting conductive film. It is formed and in contact with one of the pair of conductive films and the first light-transmitting conductive film.

Description

[Technical Field]

[0001] The present invention relates to a product, method, or method of manufacture. Or, the present invention relates to a process, machine Relating to a manufacturer or composition of matter. In one aspect of the present invention, a semiconductor device, a display device, a light-emitting device, a power storage device, and a method for driving them are provided. The present invention relates to, or to a method for manufacturing them. In particular, one aspect of the present invention relates to an oxide semiconductor having This relates to semiconductor devices or display devices. [Background technology]

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

[0003] In recent years, metal oxides exhibiting semiconductor properties have been used in transistors instead of silicon semiconductors. The technology is attracting attention. In this specification, metal oxides exhibiting semiconductor properties are referred to as oxides. Let's call it a semiconductor.

[0004] For example, as an oxide semiconductor, zinc oxide or an In-Ga-Zn oxide is used. A transistor is fabricated and used as a switching element for pixels in a display device. The technology is disclosed (see Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2007-123861 [Patent Document 2] Japanese Patent Publication No. 2007-96055 [Overview of the project] [Problems that the invention aims to solve]

[0006] A capacitive element has a dielectric film between a pair of electrodes, and of the pair of electrodes, at least The other electrode is a gate electrode, source electrode, or drain electrode that constitutes a transistor. They are often formed with a conductive film that has light-shielding properties.

[0007] Furthermore, in liquid crystal display devices, the larger the capacitance value of the capacitive element, the more the electric field is applied. In this, the period during which the orientation of liquid crystal molecules in a liquid crystal element can be kept constant can be extended. It is possible. When displaying a still image, the duration can be extended by rewriting the image data. This can reduce the number of cycles and is expected to lower power consumption.

[0008] To increase the capacitance value of a capacitive element, the occupied area of ​​the capacitive element must be increased, specifically One method is to increase the area where the pair of electrodes overlap. However, the liquid crystal surface In the display device, a light-shielding conductive material is used to increase the area over which the pair of electrodes overlap. Increasing the film area reduces the aperture ratio of the pixels, which degrades the display quality of the image. This problem is particularly pronounced in high-resolution liquid crystal display devices.

[0009] On the other hand, in transistors having oxide semiconductor films, changes over time and stress tests This leads to a problem where the electrical characteristics of the transistor, specifically the fluctuation in the threshold voltage, increase. Yes. Also, if a transistor has normally-on characteristics, malfunctions may occur during operation. It becomes cheaper, or power consumption when not in operation increases, or in the case of a display device, it becomes more difficult. Various problems arise, such as a decrease in signal strength. As a result, display quality deteriorates.

[0010] Therefore, one aspect of the present invention provides a display device with excellent display quality. Or, the present invention One embodiment is a display device having a capacitive element that has a high aperture ratio and can increase the capacitance value. To provide a device. Alternatively, one aspect of the present invention provides a display device with reduced power consumption. Alternatively, one aspect of the present invention provides a display device having a transistor with excellent electrical characteristics. Alternatively, one aspect of the present invention provides a novel display device. Alternatively, one aspect of the present invention is This provides a method for manufacturing a display device that has a high aperture ratio and a wide viewing angle, with a small number of manufacturing steps. Alternatively, one aspect of the present invention provides a method for manufacturing a novel display device.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. One approach does not require that all of these issues be resolved. The title will become clear from the description in the specification, drawings, claims, etc. It is possible to extract other issues from the descriptions in the drawings, claims, etc. [Means for solving the problem]

[0012] One aspect of the present invention is a transistor on a substrate, an inorganic insulating film in contact with the transistor, and An organic insulating film in contact with the mechanical insulating film, a capacitive element electrically connected to the transistor, and an organic insulating film. A display device having pixel electrodes formed on a film and electrically connected to a transistor. Yes, a transistor consists of a gate electrode on a substrate and an oxide semiconductor film that overlaps the gate electrode. A gate insulating film in contact with one side of the oxide semiconductor film, and a pair of conductive materials in contact with the oxide semiconductor film. The capacitive element has a metal oxide film on the gate insulating film, an inorganic insulating film, and an inorganic insulating film. The pixel electrode has a first light-transmitting conductive film on the edge film. It is formed of a conductive film and is in contact with one of a pair of conductive films and a first transparent conductive film.

[0013] Furthermore, one aspect of the present invention includes a transistor on a substrate and an inorganic insulating film in contact with the transistor. And, an organic insulating film in contact with an inorganic insulating film, a capacitive element electrically connected to a transistor, and A display having pixel electrodes formed on an insulating film and electrically connected to a transistor. It is a device. A transistor consists of a gate electrode on a substrate and an oxide semiconductor that overlaps the gate electrode. A film, a gate insulating film in contact with one side of the oxide semiconductor film, and a pair in contact with the oxide semiconductor film. The capacitive element has a conductive film and a gate insulating film, and one of the pair of conductive films. A metal oxide film in contact with, an inorganic insulating film, and a first light-transmitting conductive film on the inorganic insulating film. , has. The pixel electrode is formed of a second light-transmitting conductive film, and a pair of conductive films It is in contact with one side.

[0014] The above transistor has a gate electrode that overlaps with the oxide semiconductor film via an inorganic insulating film. It may also be a dual-gate structure. The gate electrode is an oxide through a gate insulating film. It may be connected to a gate electrode that overlaps with the semiconductor film.

[0015] Furthermore, the inorganic insulating film consists of an oxide insulating film in contact with the other surface of the oxide semiconductor film, and an oxide insulating film. It may also have a nitride insulating film in contact with the film.

[0016] Furthermore, the metal oxide film is formed in contact with the nitride insulating film and is made of the same gold as the oxide semiconductor film. It may contain group elements.

[0017] Furthermore, oxide semiconductor films include In-Ga oxide, In-Zn oxide, or In-MZ n oxide (where M is Al, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf) Sat.

[0018] Furthermore, the oxide semiconductor film has a multilayer structure including a first film and a second film, and the first film is The atomic ratio of the second film and the metal element may be different. [Effects of the Invention]

[0019] According to one aspect of the present invention, a display device with excellent display quality can be provided. Alternatively, According to one aspect of the present invention, a capacitive element is provided that has a high aperture ratio and can increase the capacitance value. A display device having can be provided. Alternatively, according to one aspect of the present invention, a display device having low power consumption can be provided. A reduced display device can be provided. According to one aspect of the present invention, a device with excellent electrical characteristics can be provided. A display device having a transistor can be provided. Or, according to one aspect of the present invention, It is possible to manufacture a display device with a high aperture ratio and a wide viewing angle using a small number of manufacturing steps. Alternatively, according to one aspect of the present invention, a novel display device can be provided. The description of these effects does not preclude the existence of other effects. Furthermore, one aspect of the present invention is: It is not necessarily required to have all of these effects. Other effects are described in the specification. This will become clear from the description in the drawings, claims, etc., and the specification, drawings, claims From descriptions such as these, it is possible to extract other effects. [Brief explanation of the drawing]

[0020] [Figure 1] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 2] These are block diagrams and circuit diagrams illustrating one form of a semiconductor device. [Figure 3] This is a top view illustrating one form of a semiconductor device. [Figure 4] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 5] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 6] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 7] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 8] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 9] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 10] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 11] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 12] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 13] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 14] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 15] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 16] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 17] This is a top view illustrating one form of a semiconductor device. [Figure 18] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 19]This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 20] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 21] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 22] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 23] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 24] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 25] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 26] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 27] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 28] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 29] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 30] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 31] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 32] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 33] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 34] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 35] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 36] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 37] This is a cross-sectional view illustrating one form of a method for manufacturing semiconductor devices. [Figure 38] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 39] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 40] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 41] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 42] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 43] This is a cross-sectional view illustrating one form of a semiconductor device. [Figure 44] High-resolution TEM image with Cs correction in cross-section of CAAC-OS, and schematic cross-sectional diagram of CAAC-OS. [Figure 45] High-resolution TEM image with Cs correction in the plane of CAAC-OS. [Figure 46] A diagram illustrating the XRD structural analysis of CAAC-OS and single-crystal oxide semiconductors. [Figure 47] A figure showing the electron diffraction pattern of CAAC-OS. [Figure 48] A diagram showing the changes in the crystalline structure of In-Ga-Zn oxide due to electron irradiation. [Figure 49] A schematic diagram illustrating the film deposition models for CAAC-OS and nc-OS. [Figure 50] A diagram illustrating InGaZnO4 crystals and pellets. [Figure 51] A schematic diagram illustrating the film deposition model of CAAC-OS. [Figure 52] A diagram illustrating the crystal structure of InGaZnO4. [Figure 53] A diagram illustrating the structure of InGaZnO4 before atomic collisions. [Figure 54] A diagram illustrating the structure of InGaZnO4 after atomic collisions. [Figure 55] A diagram illustrating the trajectories of atoms after a collision. [Figure 56] Cross-sectional HAADF-STEM images of CAAC-OS and the target. [Figure 57] A diagram illustrating the temperature dependence of resistivity. [Figure 58] This is a conceptual diagram illustrating an example of a method for driving a display device. [Figure 59] This is a diagram illustrating the display module. [Figure 60] This diagram illustrates the external view of an electronic device according to an embodiment. [Modes for carrying out the invention]

[0021] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention The present invention is not limited to the following description, and its form and scope may not depart from the spirit and scope of the present invention. Those skilled in the art will readily understand that the details can be modified in various ways. Therefore, the present invention The following descriptions of embodiments are not to be interpreted as being limited to the following. In the embodiments described herein, identical parts or parts having similar functions are given the same reference numerals. Alternatively, the same hatch pattern may be used in common across different drawings, and the explanation of its repetition may be omitted. ru.

[0022] In each figure described herein, the size, film thickness, or region of each component is as follows: It may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale. stomach.

[0023] Furthermore, the terms "first," "second," "third," etc. used in this specification are used to avoid confusion of constituent elements. This is a selection and not a numerical limit. Therefore, for example, "the first" This can be explained by substituting "the second" or "the third" as appropriate.

[0024] Furthermore, the functions of "source" and "drain" are used in situations where the direction of current changes during circuit operation. In this specification, "sauce" and "dressing" may be used interchangeably. The term "in" may be used interchangeably.

[0025] Furthermore, voltage refers to the potential difference between two points, while electric potential refers to the electrostatic field at a given point. This refers to the electrostatic energy (electrical potential energy) possessed by a unit charge within a given object. Furthermore, generally speaking, the potential difference between the potential at a certain point and a reference potential (for example, the ground potential) This is simply called electric potential or voltage, and the terms electric potential and voltage are often used as synonyms. Therefore, unless otherwise specified in this specification, potential may be read as voltage. You may substitute "voltage" with "potential."

[0026] In this specification, when an etching process is performed after a photolithography process: The mask formed during the photolithography process shall be removed.

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

[0028] Furthermore, in this specification, if the crystal is trigonal or rhombohedral, it is listed as hexagonal. vinegar.

[0029] (Embodiment 1) In this embodiment, a semiconductor device, which is one aspect of the present invention, will be described with reference to the drawings. .

[0030] Figure 1 shows a cross-sectional view of the transistor 103 and the capacitive element 105 of the semiconductor device.

[0031] The transistor 103 shown in Figure 1(A) is a gate electrode provided on the substrate 302. A functional conductive film 304c and a gate insulating film formed on the substrate 302 and the conductive film 304c. 51 and the oxide semiconductor film 308b which overlaps with the conductive film 304c via the gate insulating film 51 a pair of electrodes that function as source and drain electrodes and are in contact with the oxide semiconductor film 308b. It has conductive films 310d and 310e.

[0032] Furthermore, a metal oxide film 308c is provided on the gate insulating film 51. Transistor 1 An inorganic insulating film 53 is provided on 02 and the metal oxide film 308c. A conductive film 316b is provided. Metal oxide film 308c, inorganic insulating film 53, and conductive film 3 16b constitutes the capacitive element 105.

[0033] Furthermore, an organic insulating film 317 is provided on the inorganic insulating film 53 and the conductive film 316b. Furthermore, in the openings provided in the inorganic insulating film 53 and the organic insulating film 317, the conductive film 310e A conductive film 319, which connects to the conductive film 316b, is provided on the organic insulating film 317. The film 319 functions as a pixel electrode.

[0034] The metal oxide film 308c is an oxide semiconductor film formed simultaneously with the oxide semiconductor film 308b. In addition, hydrogen, boron, phosphorus, nitrogen, tin, antimony, noble gas elements, alkali metals, alkaline By introducing impurities such as earth metals or oxygen deficiencies, conductivity is improved, and conductivity is achieved. This results in a metal oxide film. Furthermore, since oxide semiconductor films are translucent, the metal oxide film 3 08c also has light-transmitting properties.

[0035] Furthermore, conductive films 316b and 319 are formed from transparent conductive films. Therefore, the capacitive element 105 is light-transmitting. For this reason, the area of ​​the capacitive element in the pixel is increased. It is possible to increase the capacitance value of the capacitive element and the aperture ratio of the pixel. .

[0036] The inorganic insulating film 53 has at least an oxide insulating film, and further comprises an oxide insulating film and a nitride It is preferable that insulating films are stacked. In the inorganic insulating film 53, the oxide semiconductor film 30 In the region in contact with 8b, an oxide insulating film is formed, thereby forming the oxide semiconductor film 308b It is possible to reduce the amount of defects at the interface between the inorganic insulating film 53 and the film.

[0037] Furthermore, the nitride insulating film functions as a barrier film against water, hydrogen, etc. Oxide semiconductor film 308 If b contains water, hydrogen, etc., the oxygen contained in the oxide semiconductor film 308b and the water, hydrogen, etc. The reaction occurs, and an oxygen vacancy is formed in the oxide semiconductor film 308b. Due to the oxygen vacancy, Carriers are generated in the oxide semiconductor film 308b, and the transistor's threshold voltage becomes negative. Due to the NAS shift, the transistor exhibits normally-on characteristics. Therefore, inorganic insulation is necessary. By providing a nitride insulating film as film 53, water can be prevented from entering the oxide semiconductor film 308b from the outside. It is possible to reduce the amount of diffusion of elements, etc., and reduce the amount of defects in the oxide semiconductor film 308b. This is possible. For this reason, in the inorganic insulating film 53, from the oxide semiconductor film 308b side The oxide insulating film and the nitride insulating film are stacked in that order, and the oxide semiconductor film 308b and The amount of defects at the interface of the inorganic insulating film 53, and the oxygen vacancies in the oxide semiconductor film 308b. It is possible to reduce the amount and fabricate transistors with normally-off characteristics. It is Noh.

[0038] The organic insulating film 317 is formed from organic resins such as acrylic resin, polyimide resin, and epoxy resin. Therefore, it has high flatness. Also, the thickness of the organic insulating film 317 is 500 nm or more. The wavelength is 0 nm or less, preferably between 1000 nm and 3000 nm.

[0039] Furthermore, the conductive film 319 formed on the organic insulating film 317 is used for the transistor 103 and the capacitance It connects to element 105. The conductive film 319 functions as a pixel electrode and is connected to the inorganic insulating film 53 and It is connected to the transistor 103 through an opening provided in the insulating film 317. That is, conductive Because the film 319 is far from the transistor 103, the conductivity of the transistor 103 The potential of film 310d is less affected. As a result, the conductive film 319 is connected to transistor 103. It is possible to superimpose the images, which can increase the aperture ratio of the pixels.

[0040] Here, as a comparative example, a transient in which an organic insulating film 317 is not formed on an inorganic insulating film 53 In a semiconductor device having a transistor 103, the gate electrode of the transistor 103 functions We will now explain the case where a negative voltage is applied to the conductive film 304c.

[0041] When a negative voltage is applied to the conductive film 304c, which functions as a gate electrode, an electric field is generated. The electric field is not shielded by the oxide semiconductor film 308b and affects the inorganic insulating film 53. A weak positive charge is accumulated on the surface of the inorganic insulating film 53. In addition, a conductive electrode functions as a gate electrode. When a negative voltage is applied to the film 304c, positively charged particles contained in the air are absorbed by the inorganic insulating film 5 It is adsorbed onto the surface of 3, and a weak positive charge is accumulated on the surface of the inorganic insulating film 53.

[0042] A positive charge is generated on the surface of the inorganic insulating film 53, creating an electric field, and this electric field is then applied to the oxide The effect extends to the interface between the semiconductor film 308b and the inorganic insulating film 53. As a result, the oxide semiconductor film 3 At the interface between 08b and the inorganic insulating film 53, a substantially positive bias is applied. As a result, the transistor's threshold voltage shifts to the negative.

[0043] On the other hand, the transistor 103 shown in this embodiment in Figure 1 is made of organic material on an inorganic insulating film 53. It has an insulating film 317. The organic insulating film 317 has a thickness of 500 nm or more, and because it is thick, This occurs when a negative voltage is applied to the conductive film 304c, which functions as a gate electrode. The electric field does not affect the surface of the organic insulating film 317, and positive electric fields do not affect the surface of the organic insulating film 317. The charge is less likely to become charged. Also, the organic insulating film 317 has a thickness of 500 nm or more, so Even if positively charged particles contained in the air are adsorbed onto the surface of the organic insulating film 317, The electric field of positively charged particles adsorbed on the surface of 317 affects the oxide semiconductor film 308b and the inorganic insulating film. The influence is minimal up to the interface 53. As a result, the oxide semiconductor film 308b and the inorganic insulating film 5 At interface 3, a positive bias is not effectively applied, and the transistor The fluctuation in the key voltage is small.

[0044] Furthermore, in the organic insulating film 317, water and other substances diffuse easily, but the inorganic insulating film 53 is nitride By having an insulating film, the nitride insulating film acts as a barrier film for water, which then diffuses into the organic insulating film 317. It is possible to prevent the water from diffusing into the oxide semiconductor film 308b.

[0045] From the above, by providing the organic insulating film 317 on the transistor, the transistor It is possible to reduce variations in electrical characteristics. Furthermore, it has normally-off characteristics, and reliability Highly reliable transistors can be fabricated. Furthermore, organic insulating films can be produced by printing or coating methods. Since it can be formed using the above, the manufacturing time can be shortened. By providing a conductive film that functions as a pixel electrode on the organic insulating film 317, the opening in the pixel This can increase the percentage of votes.

[0046] <Example 1> A modified example of the transistor shown in this embodiment 1 will be explained using Figure 1(B). The transistor 103 shown in this modified example is an oxide semiconductor film formed using a multi-gradation mask. It is characterized by having 308e and a pair of conductive films 310f and 310g.

[0047] By using a multi-level mask, it is possible to form a resist mask with multiple thicknesses. It is possible to use the resist mask to form an oxide semiconductor film 308e, and then oxygen plasma By exposing the resist mask to a spectroscopy device, a portion of the resist mask is removed, leaving a pair of conductive films. This serves as a resist mask for formation. Therefore, the oxide semiconductor film 308e and a pair of conductive Reducing the number of photolithography steps in the fabrication process of the 310f and 310g film can.

[0048] Furthermore, the upper surface shape of the oxide semiconductor film 308e formed using a multi-gradation mask is a pair of guides The 310f and 310g film will have a shape in which a portion protrudes from the outside.

[0049] <Modification 2> In the display device shown in Embodiment 1, depending on the circumstances, for example, Alternatively, the conductive film 319 may be formed using a conductive film that has the function of reflecting light. Alternatively, the conductive film 319 may be formed using a multilayer film, and at least one of the films of the multilayer film may be A conductive film having the function of reflecting light may be used. Examples of materials include silver, aluminum, chromium, copper, tantalum, titanium, molybdenum, Tungsten or the like can be used. Alternatively, silver can be used as the conductive film 319. A laminated film in which a film is sandwiched between indium tin oxide (hereinafter referred to as ITO) films. It may be formed using a reflective display device, a semi-transparent display device, and This embodiment can be applied to light-emitting devices with a hop-emission structure, etc.

[0050] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0051] (Embodiment 2) In this embodiment, drawings illustrate a semiconductor device and a method for manufacturing the same, which are aspects of the present invention. Refer to the explanation.

[0052] Figure 2(A) shows a display device as an example of a semiconductor device. The display device shown in Figure 2(A) is , pixel section 11, scan line drive circuit 14, signal line drive circuit 16, each parallel or nearly parallel m scan lines 17 are arranged in a row and whose potential is controlled by a scan line drive circuit 14, Each is arranged in parallel or nearly parallel, and its potential is controlled by the signal line drive circuit 16. It has n signal lines 19 and, furthermore, the pixel section 11 has multiple arranged in a matrix. It has pixels 301. Also, along the signal line 19, each is arranged in parallel or approximately parallel. It has capacitance lines 25. The capacitance lines 25 are parallel or nearly parallel to each other along the scan lines 17. They may be arranged in rows. Also, the scan line drive circuit 14 and the signal line drive circuit 16 are grouped together. It is sometimes referred to as the drive circuit section.

[0053] The display device includes a drive circuit for driving multiple pixels, etc. Furthermore, the display device is separate Control circuits, power supply circuits, signal generation circuits, and backlight modules etc. are arranged on the circuit board. It includes these elements and is sometimes called a liquid crystal module.

[0054] Each scan line 17 is one of the pixels 301 arranged in m rows and n columns in the pixel section 11. It is electrically connected to the n pixels 301 arranged in that row. Also, each signal line 19 is m Of the pixels 301 arranged in rows and n columns, m pixels 301 located in any of the columns are charged. It is connected to the gas. m and n are both integers greater than or equal to 1. Also, each capacitance line 25 is in the m row. Of the n pixels 301 arranged in n columns, n pixels 301 arranged in any row and electricity They are connected precisely. Furthermore, the capacitance lines 25 run parallel or nearly parallel to each other along the signal lines 19. If they are arranged, then any of the pixels 301 arranged in m rows and n columns are arranged in one of the columns. The m pixels 301 are electrically connected.

[0055] In this context, a single pixel is defined as an area enclosed by scan lines and signal lines that displays a single color. This refers to the situation of a color display device consisting of R (red), G (green), and B (blue) color elements. In this context, the smallest unit of an image consists of three pixels: a red pixel, a green pixel, and a blue pixel. In addition to R (red), G (green), and B (blue), pixels such as yellow, cyan, and magenta can be added. This allows for improved color reproduction. In addition to R (red), G (green), and B (blue), W (white) By adding pixels, the power consumption of the display device can be reduced. In this case, by adding W (white) pixels to each of R (red), G (green), and B (blue), a liquid crystal display device is created. Because it is possible to increase the brightness of the backlight, the brightness of the backlight can be suppressed. This makes it possible to reduce the power consumption of liquid crystal display devices.

[0056] Figures 2(B) and (C) can be used for the pixel 301 of the display device shown in Figure 2(A). An example of a circuit configuration is shown.

[0057] The pixel 301 shown in Figure 2(B) consists of a liquid crystal element 31, a transistor 103, and a capacitive element 1 It has 05 and .

[0058] The potential of one of the pair of electrodes of the liquid crystal element 31 is set appropriately according to the specifications of the pixel 301. The orientation state of the liquid crystal element 31 is set according to the data being written to it. Also, multiple pixels A common potential is present in one of the pair of electrodes of the liquid crystal element 31 that each of the 301 possesses. You may also provide a different one to one of the pair of electrodes of the liquid crystal element 31 for each pixel 301 in each row. You may apply an electric potential.

[0059] Furthermore, the liquid crystal element 31 controls the transmission or non-transmission of light by the optical modulation effect of the liquid crystal. It is an element that... Note that the optical modulation effect of liquid crystals is due to the electric field applied to the liquid crystal (horizontal electric field, vertical electric field). It is controlled by an electric field in the direction or an electric field in the oblique direction. Note that the liquid crystal element 31 is Nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, thermotropic liquid crystal, Examples include iotropic liquid crystals, ferroelectric liquid crystals, and antiferroelectric liquid crystals.

[0060] The driving method for the display device having the liquid crystal element 31 is, for example, TN mode, VA mode. , ASM(Axially Symmetric Aligned Micro-cel l) Mode, OCB (Optically Compensated Birefringence) gence) mode, MVA mode, PVA (Patterned Vertical Alignment mode, IPS mode, FFS mode, or TBA (Trans You may also use modes such as Verse Bend Alignment. However, It is not limited to this, and various liquid crystal elements and their driving methods can be used.

[0061] Furthermore, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent. The liquid crystal element may be constructed in this manner. The liquid crystal exhibiting the blue phase has a response speed of 1 msec or less. Because it is short and optically isotropic, orientation processing is unnecessary and it has low dependence on the viewing angle.

[0062] In the configuration of the pixel 301 shown in Figure 2(B), the source electrode and the d One end of the rain electrode is electrically connected to the signal line 19, and the other end is connected to a pair of electrodes on the liquid crystal element 31. It is electrically connected to the other side. Also, the gate electrode of transistor 103 is connected to scan line 17. Electrically connected. Transistor 103 is either on or off. It has a function to control the writing of data to the data signal.

[0063] In the configuration of the pixel 301 shown in Figure 2(B), one of the pair of electrodes of the capacitive element 105 is It is electrically connected to the capacitance line 25 to which the potential is supplied, and the other end is connected to the pair of electrodes of the liquid crystal element 31. It is electrically connected to the other side. The potential value of the capacitance line 25 is determined according to the specifications of the pixel 301. It is set as appropriate. The capacitive element 105 is a retaining capacitor that holds the written data. To have the ability.

[0064] For example, in the display device having pixels 301 as shown in Figure 2(B), each is driven by the scan line driving circuit 14 The pixels 301 in each row are selected sequentially, and the transistor 103 is turned on to generate the data signal. Write it down.

[0065] The pixel 301 on which data has been written is retained when transistor 103 is turned off. This is the state it enters. By doing this sequentially for each row, the image can be displayed.

[0066] Furthermore, the pixel 301 shown in Figure 2(C) is a transistor 4 that performs switching of the display element. 3, a transistor 103 that controls the driving of the pixels, a transistor 45, and a capacitive element 10 It has 5 and a light-emitting element 41.

[0067] One of the source and drain electrodes of transistor 43 is a signal to which a data signal is applied. It is electrically connected to line 19. Furthermore, the gate electrode of transistor 43 is connected to the gate signal It is electrically connected to the given scan line 17.

[0068] Transistor 43 is either on or off, which controls the data of the data signal. It has a function to control writing.

[0069] One of the source and drain electrodes of transistor 103 functions as the anode wire. It is electrically connected to the wiring 47, and the source electrode and drain electrode of transistor 103 are also connected. One side is electrically connected to one electrode of the light-emitting element 41. Furthermore, the transistor 103 The gate electrode is the source electrode and the other drain electrode of transistor 43, and the capacitive element 1 It is electrically connected to one of the electrodes of 05.

[0070] Transistor 103, by being in an ON or OFF state, causes current to flow to the light-emitting element 41. It has a function to control the current being applied.

[0071] The source electrode and one of the drain electrodes of transistor 45 are given a data reference potential. The source electrode and the other drain electrode of the transistor 45 are connected to the wiring 49, and the other drain electrode emits light. It is electrically connected to one electrode of element 41 and to the other electrode of capacitive element 105. The gate electrode of transistor 45 is electrically connected to the scan line 17 to which the gate signal is applied. It will be done.

[0072] The transistor 45 has the function of adjusting the current flowing to the light-emitting element 41. For example, If the internal resistance of the light-emitting element 41 increases due to deterioration of the light-emitting element 41, the transistor 45 The current flowing through the wiring 49 to which one of the source and drain electrodes is connected is monitored. This allows the current flowing through the light-emitting element 41 to be corrected. The potential can be set to, for example, 0V.

[0073] One of the pair of electrodes of the capacitive element 105 is connected to the gate electrode of the transistor 103, and the transistor The source electrode and drain electrode of the zista 43 are electrically connected to the other, and the capacitive element 105 The other electrode of the pair is the other of the source electrode and drain electrode of transistor 45, and emits light. It is electrically connected to one electrode of element 41.

[0074] In the configuration of the pixel 301 shown in Figure 2(C), the capacitive element 105 receives the written data. It functions as a holding capacity for retaining [something].

[0075] One of the pair of electrodes of the light-emitting element 41 is connected to the source electrode and drain electrode of the transistor 45. On the other hand, the other side of the capacitive element 105, and the source electrode and drain electrode of the transistor 103. It is electrically connected to the other side. Also, the other of the pair of electrodes of the light-emitting element 41 is the cathode. It is electrically connected to the wiring 50 that functions.

[0076] As the light-emitting element 41, for example, an organic electroluminescent element (also known as an organic EL element) (u) and the like can be used. However, the light-emitting element 41 is not limited to this, and Inorganic EL elements made of mechanical materials may also be used.

[0077] Furthermore, a high power supply potential VDD is supplied to one of the wires 47 and 50, while a low power supply potential VDD is supplied to the other. A power supply potential VSS is applied. In the configuration shown in Figure 2(C), the high power supply potential is applied to wiring 47. The configuration provides VDD to the wiring 50 and a low power supply potential VSS to the wiring 50.

[0078] In the display device having pixels 301 as shown in Figure 2(C), the scan line driving circuit 14 drives the pixels of each row Select 301 sequentially, turn on transistor 43, and write the data signal. .

[0079] The pixel 301 on which data has been written is held in place when transistor 43 is turned off. It becomes a state. Furthermore, since transistor 43 is connected to capacitive element 105, it is written It becomes possible to retain the data for a long time. Also, due to transistor 43, The amount of current flowing between the source electrode and drain electrode of the zista 103 is controlled, and the light-emitting element 41 It emits light with a brightness corresponding to the amount of current flowing through it. By doing this sequentially row by row, an image is displayed. It can be demonstrated.

[0080] In Figures 2(B) and 2(C), the display elements are the liquid crystal element 31 and the light-emitting element 41. Although examples using this have been shown, the embodiments of the present invention are not limited thereto. It is also possible to use elements. For example, EL (electroluminescent) elements (organic EL elements including materials and inorganic materials, organic EL elements, inorganic EL elements), LEDs (white LEDs, red LEDs) Color LEDs (green LEDs, blue LEDs, etc.), transistors (transistors that emit light according to the current) ZISTA, electron emission element, liquid crystal element, electronic ink, electrophoretic element, grating light Valves (GLV), plasma displays (PDP), MEMS (microelectronics) Mechanical systems, digital micromirror devices (DMD), DMS (digital (Tal Micro-Shutter), IMOD (Interference Modulation) Elements, electrowetting elements, piezoelectric ceramic displays, carbon nanotubes Due to electromagnetic effects such as those described above, contrast, brightness, reflectance, and transmittance can change. Some have a display medium. An example of a display device using an EL element is an EL display. Examples include play. An example of a display device using an electron emission element is a field emitter. Surface-type display (FED) or SED type flat-panel display (SED: Surface-type display) e-conduction (Electron-emitter Display), etc. There is. An example of a display device using liquid crystal elements is a liquid crystal display (transmissive liquid crystal display). LCDs, transflective LCDs, reflective LCDs, direct-view LCDs (i) Projection liquid crystal displays, etc. Display devices using electronic ink or electrophoretic elements. One example of such a device is electronic paper.

[0081] Next, we will explain the specific configuration of the element substrate included in the display device. A VA-type liquid crystal display device is used, and the upper surface of the pixels 301 included in the liquid crystal display device The figure is shown in Figure 3.

[0082] In Figure 3, the conductive film 304c, which functions as a scanning line, is a conductive film that functions as a signal line. It is provided extending in a direction approximately perpendicular to the (left-right direction in the diagram). It functions as a signal line. The conductive film 310d and capacitance lines 310i are oriented in a direction substantially perpendicular to the conductive film that functions as a scanning line (Figure) It is provided extending in the (upper and lower) directions. The conductive film 304c, which functions as a scanning line, It is electrically connected to the scan line drive circuit 14 (see Figure 2) and functions as a signal line. The conductive film 310d is electrically connected to the signal line drive circuit 16 (see Figure 2).

[0083] Transistor 103 has a conductive film that functions as a scanning line and a conductive film that functions as a signal line. It is located in the region where they intersect. Transistor 103 functions as a gate electrode. Electrode film 304c, gate insulating film (not shown in Figure 3), channel formed on the gate insulating film The oxide semiconductor film 308b, in which a region is formed, functions as the source electrode and drain electrode. It is composed of a pair of conductive films 310d and 310e. The conductive film 304c is a scan line It also functions as a conductive film, and the region superimposed on the oxide semiconductor film 308b is a transistor It functions as the gate electrode of ZISTA 103. Also, in Figure 3, it functions as a scan line. In terms of its top surface shape, the conductive film's edges are located outside the edges of the oxide semiconductor film 308b. Therefore, the conductive film that functions as a scanning line is a light-shielding film that blocks light from light sources such as backlights. It functions as such. As a result, light is irradiated onto the oxide semiconductor film 308b contained in the transistor. This prevents fluctuations in the transistor's electrical characteristics.

[0084] Furthermore, a conductive film 316b is provided on the metal oxide film 308c via an insulating film. There is an aperture shown by a dashed line in the insulating film provided on the metal oxide film 308c. A section 362 is provided. In the opening 362, the metal oxide film 308c is an insulating film. It comes into contact with the nitride insulating film (not shown in Figure 3) contained within.

[0085] Capacitive element 105 is formed in the region where the metal oxide film 308c and the conductive film 316b overlap. The metal oxide film 308c and the conductive film 316b are light-transmitting. That is, the capacitive element 105 It is translucent.

[0086] The conductive film 319, which functions as a pixel electrode, is separated by an organic insulating film (not shown in Figure 3). It is provided on conductive film 310e and conductive film 316b. Also, conductive film 319 is provided on opening 36 At 4c, it is connected to the conductive film 310e, and at the opening 364d, it is connected to the conductive film 316b. In other words, the transistor 103, the capacitive element 105, and the conductive film 319 are electrically connected. do.

[0087] Since the capacitive element 105 is light-transmitting, the capacitive element 105 is made large within the pixel 301 (large surface It can be formed in a series. Therefore, while increasing the opening ratio, typically 50% or more is preferred. It is possible to achieve a capacity of 60% or more, and to obtain a display device with increased capacity. This is possible. For example, in a high-resolution display device, such as a liquid crystal display device, the pixel surface The product becomes smaller, and the area of ​​the capacitive element also becomes smaller. Therefore, in high-resolution display devices... Therefore, the capacitance value stored in the capacitive element becomes smaller. However, the capacitance shown in this embodiment Since element 105 is light-transmitting, by providing this capacitive element in each pixel, It is possible to increase the aperture ratio while obtaining sufficient capacitance. Typically, this is achieved when the pixel density is 200p. High-resolution display devices with a resolution of pi or higher, and even 300ppi or higher, and even 500ppi or higher. It can be used suitably in place.

[0088] Furthermore, in liquid crystal display devices, the larger the capacitance value of the capacitive element, the more the electric field is applied. In this, the period during which the orientation of liquid crystal molecules in a liquid crystal element can be kept constant can be extended. It is possible. When displaying a still image, the duration can be extended, thus reducing the number of times the image data is rewritten. The number can be reduced, and power consumption can be reduced. The structure shown allows for an increased aperture ratio even in high-resolution display devices, It can efficiently utilize light from light sources such as backlights, reducing the power consumption of the display device. It is possible.

[0089] Next, Figure 4 shows a cross-sectional view between the dashed lines C and D in Figure 3. Note that in Figure 4, The drive circuit section (top view omitted) includes the scan line drive circuit 14 and the signal line drive circuit 16. A cross-sectional view is shown at A and B. In this embodiment, a VA-type liquid crystal display is used as the semiconductor device. I will now explain the display device.

[0090] The liquid crystal display device shown in this embodiment has liquid crystals between a pair of substrates (substrate 302 and substrate 342). Element 322 is being held in place.

[0091] The liquid crystal element 322 has a conductive film 316b on top of the substrate 302 and a film that controls the orientation (hereinafter It has an alignment film 320, 352, a liquid crystal layer 321, and a conductive film 350. The conductive film 316b functions as one electrode of the liquid crystal element 322, and the conductive film 350 is liquid crystal It functions as the other electrode of element 322.

[0092] Thus, a liquid crystal display device refers to a device that has liquid crystal elements. The device includes a drive circuit for driving multiple pixels, etc. Furthermore, the liquid crystal display device is mounted on a separate substrate. This includes a control circuit, power supply circuit, signal generation circuit, and backlight module, etc., located in the same area. It is sometimes called a liquid crystal module.

[0093] In the drive circuit section, the conductive film 304a and gate insulating film 51 function as gate electrodes. insulating film 305 and insulating film 306 that function as such, and an oxide semiconductor film in which a channel region is formed. 308a, conductive films 310a and 310b that function as source and drain electrodes The transistor 102 is formed by the oxide semiconductor film 308a, which is provided on the gate insulating film 51. It is possible.

[0094] In the pixel portion, the conductive film 304c functions as the gate electrode, and the gate insulating film 51 is Functional insulating film 305 and insulating film 306, channel region formed on gate insulating film 51 The oxide semiconductor film 308b formed thereon, and the conductive material that functions as the source electrode and drain electrode. The transistor 103 is composed of the films 310d and 310e. The oxide semiconductor film 308b is provided on the gate insulating film 51. Further, on the conductive films 310d and 310e, an insulating film 312 and an insulating film 314, which are inorganic insulating

[0095] films 53, are provided as protective films. The capacitor element 105 is composed of a metal oxide film 308c that functions as one electrode, an insulating film 314 that functions as a dielectric film, and a

[0096] conductive film 316b that functions as the other electrode. The metal oxide film 308c is provided on the gate insulating film 51. An organic insulating film 317 is formed on the inorganic insulating film 53.

[0097] Also, on the organic insulating film 317, a conductive film 319 that functions as a pixel electrode is formed. The conductive film 310e and the conductive film 316b are connected by the conductive film 319.

[0098] In the drive circuit section, a conductive film 304b formed simultaneously with the conductive films 304a and 304c and a conductive film 310c formed simultaneously with the conductive films 310a, 310b, 310d, and 310e are connected by a conductive film 319a formed simultaneously with the conductive film 319.

[0099] Here, the components of the display device shown in FIG. 4 will be described below.

[0100] Conductive films 304a, 304b, and 304c are formed on the substrate 302. 04a functions as the gate electrode of the transistor in the drive circuit section. Also, the conductive film... 304b is formed in the drive circuit section and connects to the conductive film 310c. Also, the conductive film 304c It is formed in the pixel portion 11 and functions as the gate electrode of the transistor in the pixel portion.

[0101] There are no major restrictions on the material of the substrate 302, but it should at least be able to withstand subsequent heat treatment. It must have heat resistance. For example, glass substrates, ceramic substrates, quartz substrates, etc. A fire substrate or the like may be used as substrate 302. Also, from silicon or silicon carbide Chemicals made from single-crystal semiconductor substrates, polycrystalline semiconductor substrates, silicon germanium, etc. It is also possible to apply composite semiconductor substrates, SOI substrates, etc., and semiconductor elements on these substrates A substrate with a child attached may be used as the substrate 302. When using a substrate, the 6th generation (1500mm x 1850mm) and the 7th generation (1870mm) are available. m x 2200mm), 8th generation (2200mm x 2400mm), 9th generation (2400m Using large-area substrates such as m × 2800 mm, 10th generation (2950 mm × 3400 mm), etc. This makes it possible to manufacture large-scale liquid crystal display devices.

[0102] Furthermore, a flexible substrate is used as the substrate 302, and the transistor is formed directly on the flexible substrate. This may be done. Alternatively, a release layer may be provided between the substrate 302 and the transistor. Release layer After partially or completely completing the element section on top of it, it is separated from the substrate 302 and placed on another substrate It can be used to reproduce the image. In this case, the transistor is not suitable for substrates with poor heat resistance or flexible substrates. It can also be mounted on the circuit board.

[0103] The conductive films 304a, 304b, and 304c are aluminum, chromium, copper, and tantalum. , a metallic element selected from titanium, molybdenum, and tungsten, or the aforementioned metallic elements It can be formed using an alloy as a component, or an alloy combining the aforementioned metal elements. Furthermore, one or more metallic elements selected from manganese and zirconium are used. It is acceptable to have them. Also, conductive films 304a, 304b, and 304c may be single-layer or two-layer or more. A layered structure may also be used. For example, a single-layer structure of an aluminum film containing silicon, A two-layer structure in which a titanium film is laminated on a titanium film, a two-layer structure in which a titanium film is laminated on a titanium nitride film, A two-layer structure in which a tungsten film is laminated on a titanium nitride film, tantalum nitride film or tungsten nitride film A two-layer structure consisting of a tungsten film laminated on a stainless steel film, a titanium film, and aluminum on the titanium film. There are also three-layer structures, such as one in which a titanium film is layered and then a titanium film is formed on top of it. In addition to nium, titanium, tantalum, tungsten, molybdenum, chromium, neodymium, and Scandinavian An alloy film or nitride film may be used, which may be a combination of one or more elements selected from um.

[0104] Furthermore, the conductive films 304a, 304b, and 304c are made of indium tin oxide and tungsten oxide. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide Apply a light-transmitting conductive material such as indium tin oxide with added silicon oxide. It is also possible to use a laminated structure of the above-mentioned light-transmitting conductive material and the above-mentioned metal element. It is also possible.

[0105] On the substrate 302 and the conductive films 304a, 304c, and 304b, an insulating film 305 and an insulating film 306 are formed. The insulating film 305 and the insulating film 306 function as the gate insulating film 51 of the transistor in the drive circuit section and the gate insulating film 51 of the transistor in the pixel section 11. do.

[0106] As the insulating film 305, for example, a nitride insulating film such as a silicon nitride film, a silicon oxynitride film, an aluminum nitride film, or an aluminum oxynitride film is preferably used for formation.

[0107] As the insulating film 306, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, hafnium oxide, gallium oxide, or a Ga-Zn-based metal oxide, etc. may be used for formation, and it may be provided in a laminated or single-layer form. Also, as the insulating film 306 Hafnium silicate (HfSiO x ), hafnium silicate with nitrogen added (HfSi x O y N z ), hafnium aluminate with nitrogen added (HfAl x O y N z ), high-k materials such as hafnium oxide and yttrium oxide are used for formation, and thus, the gate leakage of the transistor can be reduced.

[0108] The total thickness of the insulating film 305 and the insulating film 306 is 5 nm or more and 400 nm or less, more preferably 10 nm or more and 300 nm or less, and even more preferably 50 nm or more and 250 nm or less. do.

[0109] On the insulating film 306, oxide semiconductor films 308a, 308b, and metal oxide film 308c are formed. ​The oxide semiconductor film 308a is formed in a position where it overlaps with the conductive film 304a. It functions as the channel region of the transistor in the drive circuit section. Also, oxide semiconductor film 308 b is formed in a position overlapping with the conductive film 304c, and is the channel region of the transistor in the pixel area. It functions as follows. The metal oxide film 308c functions as one electrode of the capacitive element 105. .

[0110] The oxide semiconductor films 308a, 308b, and the metal oxide film 308c are typically In -Ga oxide film, In-Zn oxide film, In-M-Zn oxide film (where M is Al, Ti, G) (a, Y, Zr, La, Ce, Nd, Sn or Hf) are available. Note that oxide semiconductor film 30 8a, 308b, and the metal oxide film 308c are translucent.

[0111] Furthermore, the oxide semiconductor films 308a, 308b, and the metal oxide film 308c are In-MZ When it is an n oxide, if the sum of In and M is 100 atomic%, then the ratio of In and M The atomic ratio is such that In is higher than 25 atomic%, M is less than 75 atomic%, and furthermore... Preferably, In is higher than 34 atomic%, and M is less than 66 atomic%.

[0112] The oxide semiconductor films 308a, 308b, and the metal oxide film 308c have an energy gap. The voltage is 2eV or more, preferably 2.5eV or more, and more preferably 3eV or more. Furthermore, by using oxide semiconductors with a wide energy gap, the off-current of the transistor can be reduced. This can be reduced.

[0113] The thickness of the oxide semiconductor films 308a, 308b, and the metal oxide film 308c is 3 nm or more. 200nm or less, preferably 3nm to 100nm, more preferably 3nm to 5nm The nm size should be 0 nm or less.

[0114] In:Ga:Z is used as the oxide semiconductor film 308a, 308b, and metal oxide film 308c. I with an atomic ratio of n=1:1:1, In:Ga:Zn=1:1:1.2, or 3:1:2 n-Ga-Zn oxide can be used. Note that oxide semiconductor films 308a and 308b The atomic ratios of the metal oxide film 308c and the atomic ratios of the metal oxide film 308c are, respectively, plus the above atomic ratios as an error. Includes fluctuations of -20%.

[0115] Furthermore, the oxide semiconductor films 308a, 308b, and the metal oxide film 308c are, for example, non-single A crystalline structure is also acceptable. Non-single-crystal structures include, for example, CAAC-OS(C Axis), which will be discussed later. Aligned Crystalline Oxide Semiconductor) This includes polycrystalline structures, microcrystalline structures (described later), or amorphous structures. In non-single-crystal structures, The amorphous structure has the highest defect level density, while CAAC-OS has the lowest defect level density. The oxide semiconductor films 308a, 308b, and metal oxide film 308c have the same crystallinity. ru.

[0116] Furthermore, the oxide semiconductor films 308a, 308b, and the metal oxide film 308c have an amorphous structure. Region of microcrystalline structure, region of polycrystalline structure, region of CAAC-OS, region of single crystal structure A mixed film having two or more regions may also be a mixed film having, for example, regions with an amorphous structure, micro Which of the following regions is relevant: crystalline structure, polycrystalline structure, CAAC-OS, or single-crystal structure? Alternatively, it may be a single-layer structure having two or more regions. Furthermore, mixed films may have, for example, an amorphous structure. Regions, microcrystalline structure regions, polycrystalline structure regions, CAAC-OS regions, single crystal structure regions It may have a laminated structure of any two or more of these regions.

[0117] In the oxide semiconductor films 308a and 308b, when silicon or carbon, which is one of the Group 14 elements, is contained, the amount of oxygen deficiency increases in the oxide semiconductor films 308a and 308b, and it becomes n-type. For this reason, the concentration of silicon or carbon in the oxide semiconductor films 308a and 308b (the concentration obtained by secondary ion mass spectrometry) is set to 2×10 atoms / cm or less, preferably 2×10 18 atoms / cm 3 or less. 17 atoms / cm 3 or less.

[0118] Also, in the oxide semiconductor films 308a and 308b, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry is set to 1×10 atoms / cm 18 atoms / cm 3 or less, preferably 2×10 atoms / cm 16 atoms / cm 3 or less. Alkali metals and alkaline earth metals may generate carriers when combined with an oxide semiconductor, and the off-current of a transistor may increase. For this reason, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the oxide semiconductor films 308a and 308b. When combined with an oxide semiconductor, carriers may be generated, and the off-current of a transistor may increase. For this reason, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the oxide semiconductor films 308a and 308b. For this reason, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the oxide semiconductor films 308a and 308b.

[0119] Also, when nitrogen is contained in the oxide semiconductor films 308a and 308b, electrons, which are carriers, are generated, the carrier density increases, and it easily becomes n-type. As a result, a transistor using an oxide semiconductor containing nitrogen tends to have normally-on characteristics. Therefore, the oxide semiconductor semiconductor In semiconductor films, it is preferable to reduce nitrogen as much as possible. For example, secondary ions The nitrogen concentration obtained by mass spectrometry is 5 × 10⁻⁶. 18 atoms / cm 3 Do the following This is preferable.

[0120] For the oxide semiconductor films 308a and 308b, oxide semiconductor films with low carrier density are used. For example, oxide semiconductor films 308a and 308b have a carrier density of 1 × 10⁻⁶. 17 pieces / cm 3 The following is preferably 1 × 10 15 pieces / cm 3 More preferably 1 × 10 13 pieces / cm 3 More preferably 1 × 10 11 pieces / cm 3 The following oxide semiconductor films are used.

[0121] Furthermore, this is not limited to the semiconductor characteristics and electrical characteristics (field effect) of the transistor as needed. A suitable composition should be used depending on the fruit mobility, threshold voltage, etc. To obtain the semiconductor characteristics of the transistor, the oxide semiconductor films 308a and 308b are used as carriers. A. Appropriately determine density, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. It is preferable to make it such.

[0122] The oxide semiconductor films 308a and 308b are made of oxide semiconductors such as insulating film 306 and insulating film 312. Because it is in contact with a film formed of a material that can improve the interfacial properties with the conductive film, acid The oxide semiconductor films 308a and 308b function as semiconductors, and the oxide semiconductor films 308a and 3 Transistors containing 08b have excellent electrical properties.

[0123] Furthermore, the oxide semiconductor films 308a and 308b have low impurity concentrations and low defect level densities. By using low-temperature oxide semiconductor films, transistors with excellent electrical properties can be fabricated. This is preferable. Here, the impurity concentration is low and the defect level density is low (low oxygen deficiency). The term "high-purity intrinsic" or "substantially high-purity intrinsic" refers to a substance that is (not) intrinsic or substantially high-purity intrinsic. Oxide semiconductors, being of intrinsic purity, have few carrier sources, thus resulting in a low carrier density. In some cases, this is possible. Therefore, when channel regions are formed in the oxide semiconductor film, The inverter exhibits an electrical characteristic where the threshold voltage is negative (also known as normally-on). In some cases, this is rarely the case. Also, high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors Conductor films have a low defect level density, which can result in a low trap level density. Oxide semiconductor films that are intrinsically pure or substantially high-purity intrinsically pure exhibit remarkably low off-current. Channel width is 1 x 10 6 Even with a device with a channel length L of 10 μm in μm, the source electrode and When the voltage across the drain electrodes (drain voltage) is in the range of 1V to 10V, the off-current is Below the measurement limit of the semiconductor parameter analyzer, i.e., 1 × 10⁻⁶ -13 Characteristics of being A or less Therefore, a transient in which a channel region is formed in the oxide semiconductor film can be obtained. A transistor can sometimes be highly reliable due to its small variation in electrical characteristics. Charges trapped in the trap levels of an oxide semiconductor film take a long time to disappear. It can sometimes behave as if it were a fixed charge. Therefore, oxidation with a high trap level density Transistors in which a channel region is formed in a monocrystalline semiconductor film may have unstable electrical properties. Yes, there are impurities such as hydrogen, nitrogen, alkali metals, or alkaline earth metals.

[0124] The metal oxide film 308c was formed simultaneously with the oxide semiconductor films 308a and 308b. It is formed by processing a material semiconductor film. Therefore, the metal oxide film 308c is an oxide semiconductor film. This film has the same metallic elements as 308a and 308b. Also, oxide semiconductor film 308a , a film having a crystal structure similar to or different from 308b. However, The oxide semiconductor films 308a and 308b, formed simultaneously, contain impurities or By creating an oxygen deficiency, the film becomes conductive and functions as an electrode for a capacitive element. One of the impurities contained in oxide semiconductor films is hydrogen. These include boron, phosphorus, tin, antimony, noble gas elements, alkali metals, and alkaline earth metals. It may include species such as [specific species]. Alternatively, the metal oxide film 308c may be an oxide semiconductor film 308a , a film formed simultaneously with 308b, and oxygen vacancies formed due to plasma damage, etc. , a film with enhanced conductivity. Alternatively, the metal oxide film 308c is an oxide semiconductor film 30 This film was formed simultaneously with 8a and 308b, and also contains impurities, as well as plasma damage. This is a film in which oxygen deficiencies are formed by the use of a solvent, thereby increasing its conductivity.

[0125] Therefore, the oxide semiconductor films 308a, 308b and the metal oxide film 308c are all insulating. Although formed on film 306, the impurity concentration differs. Specifically, oxide semiconductor film 308a Compared to 308b, the impurity concentration of the metal oxide film 308c is higher. For example, oxide semiconductors The hydrogen concentration in body membranes 308a and 308b is 5 × 10⁻⁶. 19 atoms / cm 3less than, Preferably 1 × 10 19 atoms / cm 3 The following is preferably 5 × 10 18 atom / cm 3 The following is preferably 1 × 10 18 atoms / cm 3 The following is preferably 5 × 10 17 atoms / cm 3 The following is preferably 1 × 10 16 atoms / cm 3 The following are metals The hydrogen concentration contained in oxide film 308c is 8 × 10⁻⁶. 19 atoms / cm 3 The above is preferable is 1 x 10 20 atoms / cm 3 The above is more comfortable 5x10 20 atoms / cm 3 That concludes the explanation. Furthermore, compared to oxide semiconductor films 308a and 308b, the metal oxide film 30 The hydrogen concentration in 8c is twice, preferably 10 times or more.

[0126] Furthermore, the oxide semiconductor films formed simultaneously with the oxide semiconductor films 308a and 308b are plasma Exposure to ions can damage oxide semiconductor films and create oxygen vacancies. For example, a film can be deposited on an oxide semiconductor film using plasma CVD or sputtering. Then, the oxide semiconductor film is exposed to the plasma, and oxygen vacancies are created. Alternatively, insulating film 3 In the etching process for forming 12, the oxide semiconductor film is exposed to plasma. Then, an oxygen vacancy is created. Alternatively, the oxide semiconductor film can absorb hydrogen, noble gases, ammonia, or acid. Exposure to a plasma containing a mixture of hydrogen and other gases creates an oxygen deficiency. The oxide semiconductor film becomes highly conductive, and the film becomes conductive, and the metal oxide film 308c It functions as such.

[0127] In other words, the metal oxide film 308c can be said to be formed from a highly conductive oxide semiconductor film. Furthermore, it can be said that the metal oxide film 308c is formed from a highly conductive metal oxide film.

[0128] Furthermore, 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 an oxide semiconductor film, it combines with oxygen in the oxide semiconductor film, Electrons are generated as rear electrons. Also, the silicon nitride film is processed by plasma CVD or sputtering. When a film is deposited using the ring method, the oxide semiconductor film is exposed to plasma, and oxygen vacancies are created. When hydrogen contained in the silicon nitride film enters the oxygen vacancy, electrons, which act as carriers, are generated. As a result, the oxide semiconductor film becomes highly conductive, and the metal oxide film 308c is formed. ru.

[0129] When hydrogen is added to an oxide semiconductor in which oxygen vacancies have formed, hydrogen enters the oxygen vacancy site. A donor level is formed near the conduction band. As a result, the oxide semiconductor becomes highly conductive. It becomes conductive. An oxide semiconductor that has been made conductive can be called an oxide conductor. That is, It can be said that the metal oxide film 308c is formed using an oxide conductive film. Generally, oxides Semiconductors have a large energy gap, which allows them to transmit visible light. On the other hand, acids Oxide conductors are oxide semiconductors that have donor levels near the conduction band. Therefore, the donor The effect of absorption due to the Ner level is small, and it has light transmittance to visible light comparable to oxide semiconductors. do.

[0130] The metal oxide film 308c has lower resistivity than the oxide semiconductor films 308a and 308b. The resistivity of oxide film 308c is 1 × 10⁻⁶ of the resistivity of oxide semiconductor films 308a and 308b. - 8 1×10 times more -1 It is preferable that it be less than a multiple, typically 1 × 10⁻⁶. -3 Ωcm or larger 1 x 10 4 Less than Ωcm, more preferably with resistivity of 1 × 10⁻⁶. -3 Ωcm or more, 1 × 10 - 1 It should be less than Ωcm.

[0131] However, one embodiment of the present invention is not limited thereto, and the metal oxide film 308c is In some cases, it is possible that the insulating film 314 is not in contact with the other element.

[0132] Furthermore, one embodiment of the present invention is not limited thereto, and the metal oxide film 308c is in the Depending on the circumstances, even if the oxide semiconductor film 308a or 308b is formed in separate processes... Good. In that case, the metal oxide film 308c is, They may have different materials. For example, the metal oxide film 308c may be ITO, or It may also be formed using zinc oxide or the like.

[0133] In the liquid crystal display device shown in this embodiment, the capacitive elements are light-transmitting. As a result, the capacitive elements This allows for increasing the area occupied by the child while also increasing the aperture ratio of the pixels.

[0134] The conductive films 310a, 310b, 310c, 310d, and 310e use aluminum as the conductive material. Titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, A single metal consisting of silver, tantalum, or tungsten, or an alloy with these as the main component. It is used as a single-layer or multilayer structure. For example, a single-layer structure of an aluminum film containing silicon. The structure consists of a two-layer structure with a titanium film laminated on an aluminum film, and a titanium film laminated on a tungsten film. A layered two-layer structure, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, A titanium film or titanium nitride film, and aluminum layered on top of the titanium film or titanium nitride film. A three-layer structure in which a titanium film or copper film is laminated, and then a titanium film or titanium nitride film is formed on top of that. Molybdenum film or molybdenum nitride film and the molybdenum film or molybdenum nitride film An aluminum film or copper film is layered on top, and then a molybdenum film or nitride film is placed on top of that. Some structures include a three-layer structure that forms a molybdenum film. Other materials include indium oxide, tin oxide, or pyroxene oxide. A transparent conductive material containing lead may also be used.

[0135] insulating film 306, oxide semiconductor films 308a, 308b, metal oxide film 308c, and conductive On films 310a, 310b, 310c, 310d, and 310e, an inorganic insulating film 53 is provided. Insulating films 312 and 314 are formed. Insulating film 312 is similar to insulating film 306. It is preferable to use a material that can improve the interfacial properties with the oxide semiconductor film. It can be formed using an oxide insulating film. Here, the insulating film 312 is an insulating film. The film is formed by stacking films 312a and 312b.

[0136] The insulating film 312a is an oxide insulating film that permeates oxygen. When forming the insulating film 312b to be formed on, the oxide semiconductor films 308a, 308b, and gold It also functions as a damage mitigation film for the 308c oxide film.

[0137] The insulating film 312a has a thickness of 5 nm to 150 nm, preferably 5 nm to 5 Silicon oxide films, silicon oxide nitride films, etc., with a wavelength of 0 nm or less can be used. In the details, a silicon oxidizide film is defined as having a composition in which the oxygen content is greater than the nitrogen content. The term refers to a film with a high nitrogen content; a silicon nitride film, in terms of its composition, has a higher nitrogen content than oxygen. It refers to a membrane.

[0138] Furthermore, the insulating film 312a is an oxide insulating film, and the oxide insulating film contains nitrogen, A low number of defects is preferable.

[0139] A typical example of an oxide insulating film containing nitrogen and having a low defect rate is silicon oxidnitride film. Examples include aluminum oxide nitride films.

[0140] Oxide insulating films containing nitrogen and having a low defect rate can be obtained by measuring them at an ESR of 100K or lower. In the resulting spectrum, the first signal has a g value between 2.037 and 2.039. A second signal is given if the g value is between 2.001 and 2.003, and the g value is between 1.964 and 1.96 A third signal of 6 or less is observed. Note that the first signal and the second signal, and The split width between the second and third signals is approximately 5 m in the X-band measurement. It is T. Also, the first signal is when the g value is between 2.037 and 2.039, and the g value is 2.0 A second signal between 01 and 2.003, and a g value between 1.964 and 1.966. The sum of the spin densities of a third signal is 1 × 10⁻⁶ 18 spins / cm 3 Less than For example, 1 x 10 17 spins / cm 3 The above 1 x 1018 spins / cm 3 Not yet It is full.

[0141] Furthermore, in ESR spectra below 100K, the g value must be between 2.037 and 2.039. The first signal, the second signal with a g value of 2.001 or more and 2.003 or less, and the g value of 1 A third signal between 0.964 and 1.966 indicates nitrogen oxides (NOx). x x is between 0 and 2. The following corresponds to a signal caused by (preferably 1 to 2). Typical examples of nitrogen oxides are These include nitric oxide, nitrogen dioxide, etc. That is, the first g value is 2.037 or higher and 2.039 or lower. The first signal, the second signal with a g value of 2.001 or higher and 2.003 or lower, and the second signal with a g value of 1.9 The smaller the sum of the spin densities of the third signal, which is between 64 and 1.966, the less oxidation occurs. It can be said that the nitrogen oxide content in the insulating film is low.

[0142] As described above, if the insulating film 312a has a low nitrogen oxide content, the insulating film 312a and This makes it possible to reduce carrier trapping at the interface with the oxide semiconductor film. As a result, it is possible to reduce the fluctuation in the threshold voltage of transistors included in semiconductor devices. This reduces variations in the electrical characteristics of the transistor.

[0143] Furthermore, insulating film 312a is SIMS (Secondary Ion Mass Spectrometer). The nitrogen concentration measured by ctrometry is 6 × 10 20 atoms / cm 3 Below It is preferable that nitrogen oxides are less likely to be generated in the insulating film 312a. Furthermore, the carriers at the interface between the insulating film 312a and the oxide semiconductor films 308a and 308b It is possible to reduce traps. Also, the structure of transistors included in semiconductor devices It is possible to reduce the shift in the value voltage, thereby reducing fluctuations in the electrical characteristics of the transistor. It is possible.

[0144] Furthermore, if nitrogen oxides and ammonia are present in the insulating film 312a, the fabrication process will be difficult. During the heat treatment process in the manufacturing process, nitrogen oxides and ammonia react to form nitrogen acid. The nitrogen oxides are released as nitrogen gas. As a result, the nitrogen concentration of the insulating film 312a and the nitrogen oxides are increased. The content of can be reduced. Also, insulating film 312a and oxide semiconductor film 308a, It is possible to reduce carrier trapping at the interface with 308b. It is possible to reduce the threshold voltage shift of transistors included in the device. This can reduce variations in the electrical characteristics of the transistor.

[0145] Furthermore, in the insulating film 312a, all of the oxygen that enters the insulating film 312a from the outside is absorbed by the insulating film. Some oxygen remains in the insulating film 312a without moving to the outside of 312a. As oxygen enters a, the oxygen contained in the insulating film 312a moves to the outside of the insulating film 312a. This may cause oxygen to move within the insulating film 312a.

[0146] When an oxygen-permeable oxide insulating film is formed as the insulating film 312a, The oxygen that desorbs from the insulating film 312b is provided and is absorbed through the insulating film 312a into the oxide semiconductor It can be moved to membranes 308a and 308b.

[0147] An insulating film 312b is formed so as to be in contact with the insulating film 312a. The insulating film 312b is It is formed using an oxide insulating film containing more oxygen than satisfactorily satisfying the stoichiometric composition. An oxide insulating film containing more oxygen than satisfactorily satisfying the stoichiometric composition will, upon heating, release one of the oxygen molecules. A portion is removed. An oxide insulating film containing more oxygen than satisfies the stoichiometric composition is T DS analysis showed that the amount of oxygen removed, converted to oxygen atoms, was 1.0 × 10⁻⁶. 18 atoms / cm 3 Preferably 3.0 × 10 20 atoms / cm 3 The above is an oxide insulating film. Furthermore, the surface temperature of the film during the above TDS analysis should be between 100°C and 700°C. Alternatively, a temperature range of 100°C to 500°C is preferred.

[0148] The insulating film 312b has a thickness of 30 nm or more and 500 nm or less, preferably 50 nm or less. Silicon oxide, silicon oxide nitride, etc., with a wavelength of 400 nm or less can be used.

[0149] Furthermore, the insulating film 312b preferably has a low defect count, and typically, in ESR measurements... Furthermore, the spin density of the signal appearing at g=2.001 originating from silicon dangling bonds is reduced. The degree is 1.5 × 10 18 spins / cm 3 Less than, and even 1 x 10 18 spins / cm 3 The following is preferable. Note that insulating film 312b is oxide compared to insulating film 312a. Because it is far from the semiconductor films 308a and 308b, it has a higher defect density than the insulating film 312a. That's fine.

[0150] The insulating film 314 contains blocks of oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. By providing a nitride insulating film having a rubbing effect, oxide semiconductor films 308a, 308b, and This prevents the diffusion of oxygen from the metal oxide film 308c to the outside. Nitride insulating film and For example, silicon nitride film, silicon oxide nitride film, aluminum nitride film, aluminum oxide nitride It has a umbellate film, etc.

[0151] Furthermore, it has a blocking effect on oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. An oxide insulating film having a blocking effect on oxygen, hydrogen, water, etc. is provided on the nitride insulating film. It may also be used. As an oxide insulating film having a blocking effect on oxygen, hydrogen, water, etc., an oxide Aluminum oxide nitride, gallium oxide, gallium oxide nitride, yttrium oxide Examples include yttrium oxide nitride, hafnium oxide, and hafnium oxide nitride. Also, capacity To control the capacitance value of the element, oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. Even if a nitride insulating film or oxide insulating film is appropriately provided on a nitride insulating film having a rocking effect good.

[0152] The conductive film 316b is formed on the insulating film 314 and functions as an electrode of a capacitive element. can.

[0153] The conductive film 316b can be formed using a light-transmitting conductive material. Examples of light-transmitting conductive materials include indium oxide containing tungsten oxide, and tungsten oxide. Indium zinc oxide containing ngsten, indium oxide containing titanium oxide, titanium oxide Indium tin oxide containing nitrile, ITO, indium zinc oxide, and silicon dioxide are added. Examples include tin oxide.

[0154] The organic insulating film 317 is an organic resin such as acrylic resin, polyimide, or epoxy resin. It can be used. The organic insulating film 317 is preferably 500 nm to 5000 nm. The thickness shall be between 1000 nm and 3000 nm. The thickness of the organic insulating film 317 shall be the above thickness. By doing so, it becomes possible to fill the recesses on the conductive film 316b with the organic insulating film 317. Yes, and it is possible to reduce the unevenness in the region where the alignment film 320 is formed.

[0155] By forming an organic insulating film 317 using an organic resin, it 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 liquid crystal layer 32 It is possible to reduce the alignment unevenness of the liquid crystal material that makes up 1.

[0156] Furthermore, conductive films 319 and 319a are formed on the organic insulating film 317. 19 functions as a pixel electrode. The conductive film 319a is located at the opening 364a (see Figure 9(A)). .) is electrically connected to the conductive film 310a, and the opening 364b (see Figure 9(A)). In this case, the conductive film 310c is electrically connected. That is, conductive film 304a and conductive film 310 It functions as a connecting electrode that connects to c.

[0157] The organic insulating film 317 is not limited to this. For example, the organic insulating film 317 is color film It can also have the functions of a ruta or black matrix. For example, organic insulating film 3 If 17 has a color filter function, for example, red pixels, blue pixels, green A colored organic insulating film 317 can be formed for each color, corresponding to the colored pixels.

[0158] The conductive films 319 and 319a use a conductive material that is light-transmitting, similar to the conductive film 316b. It can be formed by [doing something].

[0159] Furthermore, in order to create a connection structure in which conductive film 304a and conductive film 310c are in direct contact, Before forming the film 310c, in order to form openings in the insulating film 305 and insulating film 306, Turning is required to form a mask. However, as shown in Figure 4, the conductive film By connecting conductive film 304a and conductive film 310c with 319a, conductive film 304a Furthermore, it becomes unnecessary to fabricate a connection part in which the conductive film 310c directly contacts, and one photomask is required. This can be reduced. In other words, it is possible to reduce the manufacturing process of liquid crystal display devices.

[0160] The alignment film 320 is preferably translucent, and is typically made of acrylic resin. Organic resins such as polyimide and epoxy resin can be used.

[0161] Furthermore, a colored film (hereinafter referred to as the colored film 346) is formed on the substrate 342. The colored film 346 has the function of a color filter. A light-shielding film 344 adjacent to it is formed on the substrate 342. The light-shielding film 344 is a black matrix It functions as a suction device. Also, the colored film 346 is not necessarily required; for example, liquid crystal If the display device is monochrome, the colored film 346 may be omitted.

[0162] The colored film 346 can be any colored film that transmits light in a specific wavelength range, for example, A red (R) film that transmits light in the red wavelength range, and a green (G) film that transmits light in the green wavelength range. A film of ) or a blue (B) film that transmits light in the blue wavelength range can be used.

[0163] The light-shielding film 344 only needs to have the function of blocking light in a specific wavelength band, and is made of metal. An organic insulating film containing a film or black pigment can be used.

[0164] Furthermore, an insulating film 348 is formed on the colored film 346. The insulating film 348 is planarized It functions as a layer, or it suppresses the diffusion of impurities that the colored film 346 may contain to the liquid crystal element. It has the function of controlling.

[0165] Furthermore, a conductive film 350 is formed on the insulating film 348. The conductive film 350 is formed on the pixel portion It functions as the other of the pair of electrodes that the liquid crystal element has. Note that conductive films 319, 31 An orientation film 352 is formed on 9a and the conductive film 350.

[0166] Furthermore, a liquid crystal layer 321 is formed between the conductive films 319, 319a and the conductive film 350. Furthermore, the liquid crystal layer 321 is sealed using a sealing material (not shown) between substrate 302 and substrate 342. It is sealed between them. The sealing material is used to prevent moisture and other substances from entering from the outside. A configuration in which it comes into contact with an inorganic material is preferred.

[0167] Furthermore, the thickness of the liquid crystal layer 321 (cell gear) is between the conductive films 319, 319a and the conductive film 350. A spacer (also called a top) may be provided to maintain the position.

[0168] Regarding the method for manufacturing the element portion provided on the substrate 302 shown in the liquid crystal display device in Figure 4, This will be explained using Figures 5 to 8. Here, the element portion is provided on the substrate 302. This refers to the region sandwiched between the substrate 302 and the alignment film 320.

[0169] The films that make up a transistor (insulating films, oxide semiconductor films, metal oxide films, conductive films, etc.) are, Sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PL) It can be formed using method D). Alternatively, it can be formed by coating or printing methods. The main methods for film deposition are sputtering and plasma chemical vapor deposition (PECVD). While not representative, thermal CVD is also acceptable. An example of thermal CVD is MOCVD (organometallic chemistry). You may also use vapor deposition (VA) or ALD (atomic layer deposition) methods.

[0170] Thermal CVD is a method in which the chamber is subjected to atmospheric pressure or reduced pressure, and the raw material gas and oxidizer are simultaneously processed. The film is formed by sending the material into a chamber, reacting it near or on the substrate, and depositing it onto the substrate. To do so, since thermal CVD is a film deposition method that does not generate plasma, It has the advantage of not generating defects through damage.

[0171] Furthermore, the ALD method maintains atmospheric pressure or reduced pressure inside the chamber, and the raw material gas for the reaction is The gases are introduced into the chamber sequentially, and film deposition is carried out by repeating this sequence of gas introduction. For example By switching between each switching valve (also called a high-speed valve), two or more raw materials are introduced. The gases are supplied to the chamber in sequence, and the first raw material gas is supplied in order to prevent the mixing of multiple raw material gases. Simultaneously or afterward, an inert gas (such as argon or nitrogen) is introduced, and the second source Introducing a carrier gas. If an inert gas is introduced at the same time, the inert gas will be used as a carrier. It becomes a gas, and an inert gas may also be introduced simultaneously when introducing the second raw material gas. Instead of introducing an inert gas, the first raw material gas is discharged by vacuum evacuation, and then the second The raw material gas may be introduced. The first raw material gas is adsorbed onto the surface of the substrate to form the first layer. Then, it reacts with a second raw material gas that is introduced later, and the second layer is laminated on top of the first layer to form a thin film. A formation is created.

[0172] By controlling the gas introduction sequence and repeating this process multiple times until the desired thickness is achieved, the stepped coating can be applied. A thin film with excellent properties can be formed. The thickness of the thin film depends on the number of times the gas introduction sequence is repeated. Therefore, it can be adjusted, enabling precise film thickness control, and miniature transistors It is suitable for manufacturing.

[0173] First, prepare the substrate 302. Here, a glass substrate is used as the substrate 302.

[0174] Next, a conductive film is formed on the substrate 302, and the conductive film is processed into a desired shape, Films 304a, 304b, and 304c are formed. Note that conductive films 304a, 304b, and 304 c is formed by first patterning into the desired shape, and is covered by the mask It can be formed by etching the areas that are not present. (See Figure 5(A)).

[0175] Furthermore, typical methods for producing conductive films 304a, 304b, and 304c include sputtering. These can be formed using methods such as vacuum deposition, pulsed laser deposition (PLD), and thermal CVD. can.

[0176] Furthermore, conductive films 304a, 304b, and 304c can be produced using a film deposition apparatus utilizing ALD. A lingsten film can be formed. In this case, WF6 gas and B2H6 gas are applied sequentially. The initial tungsten film is formed by repeated introduction, and then WF6 gas and H2 gas are introduced simultaneously. It is introduced to form a tungsten film. Note that SiH4 gas is used instead of B2H6 gas. That's good too.

[0177] 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 Figure 5(A)).

[0178] Insulating film 305 and insulating film 306 were manufactured by sputtering, CVD, vacuum deposition, and PLD. It can be formed by methods such as thermal CVD. Note that insulating film 305 and insulating film 306 Forming the material continuously in a vacuum is preferable because it suppresses the inclusion of impurities.

[0179] A silicon oxide film or a silicon oxide nitride film is formed as insulating film 305 and insulating film 306. In this case, silicon-containing sedimentary gases and oxidizing gases can be used as raw material gases. Preferred. Typical examples of silicon-containing depositing gases include silane, disilane, and trisilane. Examples include silane fluoride. Oxidizing gases include oxygen, ozone, nitrous oxide, and nitrogen dioxide. There are basic elements.

[0180] Furthermore, when forming gallium oxide films as insulating film 305 and insulating film 306, MOCV It can be formed using method D.

[0181] Furthermore, as insulating film 305 and insulating film 306, an ALD-based film deposition apparatus was used, and acid When forming a hafnium film, a liquid containing a solvent and a hafnium precursor compound (hafnium Umalkoxide solution, typically tetrakisdimethylamidohafnium (TDMAH) Two types of gases are used: a raw material gas obtained by vaporizing ) and ozone (O3) as an oxidizing agent. The chemical formula for tetrakisdimethylamidehafnium is Hf[N(CH3)2]4. Other material liquids include tetrakis(ethylmethylamide)hafnium.

[0182] Furthermore, as insulating film 305 and insulating film 306, an ALD-based film deposition apparatus was used, and acid When forming an aluminum film, a solvent and a liquid containing an aluminum precursor compound ( A raw material gas obtained by vaporizing methylaluminum (TMA, etc.) and H2O as an oxidizing agent Two types of gases are used. The chemical formula for trimethylaluminum is Al(CH3)3. Other material liquids include tris(dimethylamide)aluminum and triisobutyl. Aluminum, aluminum tris(2,2,6,6-tetramethyl-3,5-hepta Examples include (e.g., 'Gionato').

[0183] Furthermore, as insulating film 305 and insulating film 306, an ALD-based film deposition apparatus was used, and acid When forming a silicon film, hexadichlorodisilane is adsorbed onto the film-forming surface, and adsorption It removes chlorine contained in the material and supplies radicals of oxidizing gas (O2, nitrous oxide) to absorb it. It reacts to kimonos.

[0184] Next, an oxide semiconductor film 307 is formed on the insulating film 306 (see Figure 5(B)).

[0185] Oxide semiconductor film 307 is produced by sputtering, coating, pulsed laser deposition, and laser - It can be formed using methods such as ablation or thermal CVD.

[0186] Sputtering gases include noble gases (typically argon), oxygen gas, and noble gas and oxygen gas. Use a mixed gas of noble gas and oxygen as appropriate. In the case of a mixed gas of noble gas and oxygen, acid should be added to the noble gas. It is preferable to increase the basic gas ratio.

[0187] Furthermore, the target should be appropriately selected according to the composition of the oxide semiconductor film to be formed. .

[0188] Furthermore, when forming an oxide semiconductor film, for example, using the sputtering method, the substrate The temperature should be between 150°C and 750°C, preferably between 150°C and 450°C, and even more preferably between 150°C and 450°C. By depositing an oxide semiconductor film at a temperature between 200°C and 350°C, CAAC-O A film of S can be formed.

[0189] Furthermore, it is preferable to apply the following conditions for forming the CAAC-OS film.

[0190] By suppressing the inclusion of impurities during film formation, it is possible to prevent the disruption of the crystalline state due to impurities. For example, the concentration of impurities present in the deposition chamber (such as hydrogen, water, carbon dioxide, and nitrogen) can be measured. It would be good to reduce it. Also, it would be good to reduce the impurity concentration in the film formation gas. Specifically, the dew point is A film-forming gas with a temperature of -80°C or lower, preferably -100°C or lower, is used.

[0191] A film deposition apparatus utilizing ALD is used to form oxide semiconductor films, such as In-Ga-Zn-O films. When forming a film, an InO layer is created by sequentially introducing In(CH3)3 gas and O3 gas repeatedly. After that, Ga(CH3)3 gas and O3 gas are introduced simultaneously to form a GaO layer, and Subsequently, Zn(CH3)2 gas and O3 gas are simultaneously introduced to form a ZnO layer. The order of these layers is not limited to this example. Also, by mixing these gases, an In-Ga-O layer or Mixed compound layers such as an In-Zn-O layer and a Ga-Zn-O layer may be formed. Alternatively, H2O gas bubbled with an inert gas such as Ar may be used instead, but it contains H It is preferable to use non-O3 gas. Also, instead of In(CH3)3 gas, In(C 2H5)3 gas may be used. Alternatively, Ga(C2H5)3 gas may be used instead of Ga(CH3)3 gas. )3 gas may be used. Alternatively, In(C2H5)3 gas may be used instead of In(CH3)3 gas. You may use Zn(CH3)2 gas.

[0192] Next, the oxide semiconductor film 307 is processed into a desired shape, thereby forming an island-shaped oxide semiconductor film 3 Form 08a, 308b, and 308d. Note that oxide semiconductor films 308a, 308b, 3 08d forms a mask by second patterning in the desired shape, and covers the mask It can be formed by etching the areas that have not been etched. Etching can be done by... By using dry etching, wet etching, or a combination of both. This can be done (see Figure 5(C)).

[0193] Furthermore, after this, heat treatment is performed to incorporate the oxide semiconductor films 308a, 308b, and 308d. The hydrogen, water, etc. contained in the oxide semiconductor films 308a, 308b, and 308d are removed. The hydrogen and water concentrations may be reduced. As a result, the oxide semiconductor film 308 is purified. a, 308b, and 308d can be formed. The temperature of the heat treatment is typically 2 The heating temperature shall be between 50°C and 650°C, preferably between 300°C and 500°C. The temperature of the process is typically between 300°C and 400°C, preferably between 320°C and 370°C. By doing the following, it is possible to reduce warping and shrinkage of substrates even on large-area substrates. This improves yield.

[0194] The heat treatment can be carried out using an electric furnace, RTA device, etc. Therefore, heat treatment can be performed at a temperature above the strain point of the substrate for a short period of time. This makes it possible to shorten the heat treatment time and reduce warping of the substrate during the heat treatment process. This is particularly preferable for large-area substrates.

[0195] Furthermore, the heat treatment is performed using nitrogen, oxygen, and ultra-dry air (preferably with a water content of 20 ppm or less). (Air) with a concentration of 1 ppm or less, preferably 10 ppb or less, or a noble gas (argon, helix) The procedure should be carried out under an atmosphere of (such as) nitrogen, oxygen, ultra-dry air, or a noble gas mixed with water. It is preferable that it does not contain elements, water, etc. Also, after heat treatment in a nitrogen or noble gas atmosphere Alternatively, heating may be performed in an oxygen or ultra-dry air atmosphere. As a result, the oxide semiconductor film contains This allows for the removal of hydrogen, water, etc., while simultaneously supplying oxygen to the oxide semiconductor film. As a result, the amount of oxygen vacancies contained in the oxide semiconductor film can be reduced.

[0196] Furthermore, if the film deposition temperature of the insulating film 311a that is formed later is set to be between 280°C and 400°C... In addition, hydrogen, water, etc. contained in the oxide semiconductor films 308a, 308b, and 308d are removed. Since this is possible, the heat treatment is unnecessary.

[0197] Next, conductive film 3 is applied to the insulating film 306 and the oxide semiconductor films 308a, 308b, and 308d. It forms 09 (see Figure 6(A)).

[0198] The conductive film 309 can be produced using methods such as sputtering, vacuum deposition, PLD, or thermal CVD. It can be formed by doing so.

[0199] Next, the conductive film 309 is processed into the desired shape, thereby creating conductive films 310a, 310b, 31 0c, 310d, and 310e are formed. Note that conductive films 310a, 310b, 310c, and 3 10d, 310e are used to form a mask by third patterning in the desired shape, and the mask It can be formed by etching the areas not covered by the scum (Figure 6(B)). reference.).

[0200] Next, insulating film 306, oxide semiconductor films 308a, 308b, 308d, and conductive film 31 Insulating film 311a, 31 1b is stacked to form an insulating film 311 (see Figure 6(C)). The insulating film 311 is spa It can be formed using methods such as tarring, CVD, and vapor deposition.

[0201] Furthermore, after forming the insulating film 311a, the insulating film 311b is continuously formed without exposure to the atmosphere. It is preferable to form it. After forming the insulating film 311a, do not open it to the atmosphere and the flow rate of the raw material gas The insulating film 311b is continuously formed by adjusting one or more of the pressure, high-frequency power, and substrate temperature. This reduces the concentration of impurities originating from atmospheric components at the interface in insulating films 311a and 311b. In addition, the oxygen contained in the insulating film 311b can be removed from the oxide semiconductor film 308a, 30 It is possible to move to 8b and 308d, and oxide semiconductor films 308a, 308b, 3 This can reduce the oxygen deficit in 08d.

[0202] As for the insulating film 311a, the oxidizing gas is more than 20 times greater than 100 times the depositional gas. The pressure should be less than 40, preferably between 40 and 80, and the pressure inside the processing chamber should be less than 100 Pa, preferably By using a CVD method with a pressure of 50 Pa or less, an oxide insulating film containing nitrogen and with a low defect rate can be produced. A border film can be formed.

[0203] As the source gas for the insulating film 311a, a silicon-containing depositing gas and an oxidizing gas are used. It is preferable to do so. Typical examples of silicon-containing sedimentary gases include silane, disilane, and Examples include silane and silane fluoride. Oxidizing gases include oxygen, ozone, and nitrous oxide. Examples include nitrogen dioxide.

[0204] By using the above conditions, an oxide insulating film that permeates oxygen is formed as the insulating film 311a. This can be achieved. Furthermore, by providing the insulating film 311a, the insulating film 311b that will be formed later can be made During the formation process, damage to the oxide semiconductor films 308a, 308b, and 308d can be reduced. It is Noh.

[0205] The insulating film 311b is placed in the vacuum-evacuated processing chamber of the plasma CVD apparatus. The substrate is kept at a temperature of 180°C to 280°C, more preferably 200°C to 240°C. The raw material gas is introduced into the processing chamber, and the pressure inside the processing chamber is set to between 100 Pa and 250 Pa. More preferably, the pressure should be 100 Pa or more and 200 Pa or less, and the electrode provided in the processing chamber should be 0. 17W / cm 2 More than 0.5W / cm 2 More preferably, 0.25 W / cm² 2 0 0.35W / cm 2 Under the following conditions for supplying high-frequency power, silicon oxide film or nitrogen oxide film A silicon dioxide film is formed.

[0206] As the source gas for insulating film 311b, a silicon-containing depositing gas and an oxidizing gas are used. It is preferable to do so. Typical examples of silicon-containing sedimentary gases include silane, disilane, and Examples include silane and silane fluoride. Oxidizing gases include oxygen, ozone, and nitrous oxide. Examples include nitrogen dioxide.

[0207] As a film deposition condition for insulating film 311b, the above-mentioned power density high frequency is used in the processing chamber at the above-mentioned pressure. By supplying power, the decomposition efficiency of the source gas in the plasma increases, and oxygen radicals increase. Furthermore, as the oxidation of the raw material gas progresses, the oxygen content in the insulating film 311b becomes stoichiometrically It becomes more than that. However, if the substrate temperature is the deposition temperature of the insulating film 311b, Because the bond between silicon and oxygen is weak, some of the oxygen is removed when heated. As a result, chemical Oxidation occurs when a substance contains more oxygen than satisfactorily satisfactorily, and some of the oxygen is removed upon heating. A material insulating film can be formed. Also, oxide semiconductor films 308a, 308b, 308d An insulating film 311a is provided on top. Therefore, in the process of forming the insulating film 311b, The insulating film 311a acts as a protective film for the oxide semiconductor films 308a, 308b, and 308d. As a result, damage to oxide semiconductor films 308a, 308b, and 308d is reduced while maintaining high power. - An insulating film 311b can be formed using high-density high-frequency power.

[0208] Furthermore, in the film deposition conditions for insulating film 311b, silicon-containing deposition properties in response to oxidizing gases By increasing the gas flow rate, it is possible to reduce the number of defects in the insulating film 311b. Tablewise, ESR measurement showed g = 2.001, which originates from silicon dangling bonds. The spin density of the signal appearing is 6 × 10 17 spins / cm 3 Less than 3 × 10 17 spins / cm 3 The following is preferably 1.5 × 10 17 spins / cm 3 Below This allows for the formation of an oxide insulating film containing nitrogen and having a low defect rate. This can improve the reliability of the generator.

[0209] Next, a heat treatment is performed. The temperature of this heat treatment is typically 150°C or higher until the substrate strain point is reached. A temperature of 200°C to 450°C, more preferably 300°C to 450°C. The temperature of the heat treatment is typically 300°C to 400°C, preferably. By maintaining a temperature between 320°C and 370°C, warping and shrinkage of the substrate are prevented even in large-area substrates. This makes it possible to reduce the yield, improving the return on investment.

[0210] The heat treatment can be carried out using an electric furnace, an RTA device, etc. Therefore, heat treatment can be performed at a temperature above the strain point of the substrate for a short period of time. Processing time can be reduced.

[0211] The heat treatment involves nitrogen, oxygen, and ultra-dry air (with a water content of 20 ppm or less, preferably 1 ppm). Air with a podium level of 10 ppb or less (preferably 10 ppb or less), or a noble gas (argon, helium, etc.) The procedure should be carried out under the following conditions. Note that the above-mentioned nitrogen, oxygen, ultra-dry air, or noble gases may contain hydrogen and water. It is preferable that the following are not included.

[0212] This heat treatment removes some of the oxygen contained in the insulating film 311b from the oxide semiconductor film 308a. , move to 308b and 308d, and the oxide semiconductor films 308a, 308b and 308d are contained within them. It is possible to reduce the amount of oxygen vacancy. As a result, oxide semiconductor films 308a, 30 The amount of oxygen deficiency in 8b and 308d can be further reduced.

[0213] Furthermore, if the insulating films 311a and 312b contain water, hydrogen, etc., the water, hydrogen, etc. can be blocked. An insulating film 313 having a coating function is subsequently formed and heat treatment is performed, and the insulating film 311a, Water, hydrogen, etc. contained in 311b migrate to oxide semiconductor films 308a, 308b, and 308d. As a result, defects occur in the oxide semiconductor films 308a, 308b, and 308d. By heating, water, hydrogen, etc. contained in the insulating films 311a and 311b are removed. This is possible, reducing variations in the electrical characteristics of transistors and also reducing fluctuations in the threshold voltage. It can be suppressed.

[0214] Furthermore, by forming the insulating film 311b on the insulating film 311a while heating, oxide semiconductors Oxygen is transferred to the body membranes 308a, 308b, and 308d, and oxide semiconductor films 308a, 308 Since it is possible to reduce the amount of oxygen deficiency contained in b, 308d, this heat treatment is performed. You don't have to.

[0215] Furthermore, when forming conductive films 310a, 310b, 310c, 310d, and 310e, The oxide semiconductor films 308a, 308b, and 308d are damaged by etching. The back channels of oxide semiconductor films 308a and 308b (oxide semiconductor films 308a, 3 In 08b, the conductive films 304a and 304c, which function as gate electrodes, are opposite to the surface facing them. Oxygen deficiency occurs on the opposite side. However, an acid that satisfies the stoichiometric composition in the insulating film 311b By applying an oxide insulating film containing more oxygen than the element, the back can be treated by heat treatment. This allows for the repair of oxygen vacancies that occur on the channel side. This enables the oxide semiconductor film 30 Because defects in 8a and 308b can be reduced, the reliability of the transistor can be improved. It can be raised.

[0216] The heat treatment may be performed after the opening 362, which is formed later, has been created.

[0217] Next, the insulating film 311 is processed into the desired shape to form the insulating film 312 and the opening 362 The insulating film 312 and the opening 362 are formed by a fourth patterning of the desired shape. A mask is formed using a etchant, and the areas not covered by the mask are etched. It can be formed (see Figure 7(A)).

[0218] The opening 362 is formed so that the surface of the oxide semiconductor film 308d is exposed. For example, a dry etching method can be used to form the opening 362. It is preferable to etch the insulating film 311 by the Lye etching method. As a result, acid Since the oxide semiconductor film 308d is exposed to plasma during the etching process, It is possible to increase the amount of oxygen deficiency in membrane 308d. However, the method of forming the opening 362 Legally, this is not limited to, but also includes wet etching methods or dry etching methods. A formation method combining this with the wet etching method may also be used.

[0219] Next, an insulating film 313 is formed on the insulating film 312 and the oxide semiconductor film 308d (Figure 7( See B). ).

[0220] The insulating film 313 is a barrier against external impurities, such as oxygen, hydrogen, water, alkali metals, It is preferable to use a material that prevents alkaline earth metals, etc., from diffusing into the oxide semiconductor film. Furthermore, it is preferable that the material contains hydrogen, and typically an inorganic insulating material containing nitrogen, such as a nitride. An insulating film can be used. Examples of insulating films 313 include those produced by CVD, sputtering, etc. It can be formed using the G method.

[0221] When insulating film 313 is deposited by plasma CVD or sputtering, an oxide semiconductor is formed. The film is exposed to plasma, and oxygen vacancies are created in the oxide semiconductor film. Alternatively, insulating film 313 This is because external impurities, such as water, alkali metals, and alkaline earth metals, can cause oxide semiconductors to form. It is a membrane formed of a material that prevents diffusion into the body membrane, and furthermore, it contains hydrogen. Therefore, it is an insulator. When hydrogen from film 313 diffuses into oxide semiconductor film 308d, When hydrogen combines with oxygen, electrons, which act as carriers, are produced. Alternatively, in an oxide semiconductor film... When hydrogen fills the oxygen vacancies, electrons, which act as carriers, are generated. The oxide semiconductor film 308d becomes highly conductive and transforms into a metal oxide film 308c.

[0222] Furthermore, the insulating film 313 is preferably formed at a high temperature in order to enhance its blocking properties. For example, substrate temperature 100°C to 400°C, more preferably 300°C to 400°C. It is preferable to heat and form the film at the specified temperature. Oxygen is desorbed from the oxide semiconductor used as 308a and 308b, and the carrier concentration increases. Since this phenomenon may occur, the temperature should be set so that this phenomenon does not occur.

[0223] Next, a conductive film 315 is formed on the insulating film 314 (see Figure 8(A)).

[0224] The conductive film 315 can be formed, for example, by a sputtering method.

[0225] Next, the conductive film 315 is processed into the desired shape to form 316b. The film 316b is subjected to a fifth patterning process to form a mask in the desired shape, and the mask It can be formed by etching the uncovered areas (see Figure 8(B)). .

[0226] Next, an organic insulating film 317 is formed to cover the insulating film 314 and the conductive film 316b (Figure 8). (See (C).) The organic insulating film 317, which functions as a planarizing film, is the insulating film 313 and the conductive film Each of the 316b has an opening so that a portion of it is exposed.

[0227] As the organic insulating film 317, coating methods such as spin coating and dip coating are used. After coating the photo-active composition onto the insulating film 313 and the conductive film 316b, a sixth photomask is used. The composition is exposed and developed using the photolithography process, and then subjected to heat treatment. Furthermore, when a non-photosensitive composition is applied to the insulating film 313 and the conductive film 316b, the non-photosensitive A resist is applied to the composition, and a photolithography process using a sixth photomask is performed. Further processing of the resist to form a mask, and using this mask to etch the non-photosensitive composition By doing so, an organic insulating film 317 can be formed.

[0228] Furthermore, the organic insulating film 317 is formed using wet methods such as inkjet printing or other printing methods. This reduces the number of photomasks required.

[0229] Next, using the organic insulating film 317 as a mask, insulating film 305, insulating film 306, insulating film 312 and a portion of the insulating film 313 are etched to expose the conductive film 304b. 364a, an opening that exposes the conductive film 310c, 364b, an opening that exposes the conductive film 310e An opening 364d is formed that exposes 364c and the conductive film 316b (see Figure 9(A)). ).

[0230] Next, a conductive film 318 is formed (see Figure 9(B)).

[0231] The conductive film 318 can be formed, for example, by a sputtering method.

[0232] Next, conductive films 319 and 319a are formed by processing the conductive film 318 into a desired shape. Furthermore, the conductive films 319 and 319a are masked by the seventh patterning process to form the desired shape. It can be formed by performing the formation and etching the areas not covered by the mask. (See Figure 9(C)).

[0233] In the above steps, a pixel section having a transistor and a drive circuit section are formed on the substrate 302. This is possible. In addition, in the manufacturing process shown in this embodiment, the first to seventh patterns This refers to the process of simultaneously forming transistors and capacitive elements using seven photomasks. It is possible.

[0234] In this embodiment, hydrogen contained in the insulating film 314 is expanded into the oxide semiconductor film 308d. The conductivity of the oxide semiconductor film 308d was increased by scattering, but the oxide semiconductor films 308a and 30 8b is covered with a mask, and impurities, typically hydrogen, boron, and lysate, are added to the oxide semiconductor film 308d. By adding tin, antimony, noble gas elements, alkali metals, alkaline earth metals, etc., acid The conductivity of the oxide semiconductor film 308d may be increased. Hydrogen and boron may be added to the oxide semiconductor film 308d. Methods for adding phosphorus, tin, antimony, noble gas elements, etc. include ion doping. , ion implantation, etc. On the other hand, alkali metals and alkaline earth elements are used in oxide semiconductor films 308d. As a method for adding metals, etc., a solution containing the impurities is applied to the oxide semiconductor film 308d. There is a way to do it.

[0235] Next, regarding the element portion provided on the substrate 342 which is provided opposite the substrate 302, The following explanation will be given. Here, the element portion provided on the substrate 342 is referred to as the substrate 342 This refers to the region sandwiched between the aligning film 352.

[0236] First, prepare substrate 342. The materials used for substrate 342 are the same as those used for substrate 302. This can be done. Next, a light-shielding film 344 and a colored film 346 are formed on the substrate 342 (Figure 10( See A). ).

[0237] The light-shielding film 344 and the colored film 346 are produced using various materials by printing, inkjet, and These are formed at the desired locations using etching methods such as photolithography.

[0238] Next, an insulating film 348 is formed on the light-shielding film 344 and the colored film 346 (see Figure 10(B)). Light. ).

[0239] Examples of insulating film 348 include organic insulating films such as acrylic resin, epoxy resin, and polyimide. A border film can be used. By forming an insulating film 348, for example, a colored film 34 This can suppress the diffusion of impurities contained in 6 towards the liquid crystal layer 321. Furthermore, the insulating film 348 is not necessarily required, and a structure without the insulating film 348 can be formed. That's good too.

[0240] Next, a conductive film 350 is formed on the insulating film 348 (see Figure 10(C)). Conductive film 35 For 0, the material shown in conductive film 315 can be used.

[0241] The structure to be formed on the substrate 342 can be created through the above process.

[0242] Next, the insulating film 31 formed on substrate 302 and substrate 342, more specifically on substrate 302 4. Conductive films 319, 319a and conductive film 350 formed on substrate 342, respectively Alignment film 320 and alignment film 352 are formed. Alignment film 320 and alignment film 352 are formed by rubbing method. It can be formed using a photo-alignment method or the like. Subsequently, between substrate 302 and substrate 342 A liquid crystal layer 321 is formed. The method for forming the liquid crystal layer 321 is the dispenser method (dropping method). Alternatively, the substrates 302 and 342 are bonded together, and then liquid crystal is injected using capillary action. The entry method can be used.

[0243] By following the above steps, the liquid crystal display device shown in Figure 4 can be manufactured.

[0244] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0245] (Embodiment 3) In this embodiment, we describe a liquid crystal display device having a different transistor than that of Embodiment 1. This will be explained using Figures 11 to 15.

[0246] The liquid crystal display device shown in Figure 11 has a dual gate structure in the drive circuit section shown AB. It is characterized by having transistor 102a.

[0247] The transistor 102a provided in the drive circuit section has a gate electrode provided on the substrate 302. A conductive film 304a functions as a electrode, and insulating films 305 and 3 function as gate insulating films. 06, an oxide semiconductor film 308a formed on the insulating film 306, and an oxide semiconductor film 308 A conductive film 310a, 310b that is in contact with a and functions as a source electrode and drain electrode It has. In addition, an inorganic insulating film 5 is placed on the oxide semiconductor film 308a and the conductive films 310a and 310b. 3 is formed, and a conductive film 316d that functions as a gate electrode is formed on the inorganic insulating film 53. The conductive film 316d, which functions as a gate electrode, consists of the gate insulating film 51 and the inorganic insulating film 53. In an opening (not shown) provided therein, a conductive film 304 functions as a gate electrode. It is connected to a. That is, conductive film 304a and conductive film 316a are at the same potential.

[0248] Therefore, by applying a voltage of the same potential to each gate electrode of transistor 102a, Reduced variation in period characteristics, suppression of degradation in GBT stress tests, and different drain voltages. It is possible to suppress fluctuations in the rise voltage of the on-current. Also, oxide semiconductor film 308 In a, the region where carriers flow becomes larger in the film thickness direction, therefore, carrier movement The dynamics increase. As a result, the on-current of transistor 102a increases, and the field effect also increases. The fruit mobility increases, and typically the field effect mobility is 20 cm. 2 / V·s or greater.

[0249] At the edges of oxide semiconductor films processed by etching, etc., damage during processing occurs. As more defects are formed and contamination occurs due to impurity adhesion, etc., electric fields and other stresses The presence of a specific component makes it easier to activate, which in turn makes it more likely to become n-type (low resistance). Therefore, the oxide semiconductor film 308a overlaps with the conductive film 304a which functions as a gate electrode. The ends tend to become n-shaped. These n-shaped ends are the source electrode and the drain. When placed between conductive films 310a and 310b that function as electrodes, the n-type region It becomes a carrier path, and parasitic channels are formed. However, the channel width In this direction, a conductive film 316d that functions as a gate electrode is provided, Due to the influence of the electric field of the conductive film 316d, which functions as an electrode, the side of the oxide semiconductor film 308a or the development of parasitic channels is suppressed at the ends, including the sides and their vicinity. As a result, the rise in drain current at the threshold voltage is steep, and the transient has excellent electrical characteristics. Become a star.

[0250] The conductive film 316d, which functions as a gate electrode, is the conductive film 316 shown in Embodiment 2. Similar materials to those used in b can be used as appropriate.

[0251] <Example 1> The liquid crystal display device shown in Figure 11 of Embodiment 3 uses a dual transistor in the drive circuit section. Although it is fabricated using an algate structure transistor, as shown in Figure 12, AB The drive circuit shown has a dual-gate transistor 102a, and CD A dual-gate transistor 103a may be used in the pixel section shown.

[0252] Transistor 103a is a conductive film provided on the substrate 302 that functions as a gate electrode. 304c, insulating films 305 and 306 which function as gate insulating film 51, and on insulating film 306 An oxide semiconductor film 308b formed therein, and a source electrode in contact with the oxide semiconductor film 308b. It also has conductive films 310d and 310e that function as drain electrodes. An inorganic insulating film 53 is formed on the conductive film 308b and the conductive films 310d and 310e, providing inorganic insulation. A conductive film 316e that functions as a gate electrode is formed on film 53. The conductive film 316e is provided in the gate insulating film 51 and the inorganic insulating film 53 at the openings (Figure (Not shown.) It is connected to the conductive film 304c which functions as a gate electrode. The conductive film 304c and the conductive film 316e are at the same potential.

[0253] Along with the drive circuit section, the pixel section has high reliability, high on-current, and high field-effect mobility. By incorporating a dual-gate transistor structure, a liquid crystal display device with superior display quality can be created. It can be manufactured.

[0254] <Modification 2> In the liquid crystal display device shown in Embodiment 2 or Embodiment 3, as shown in Figure 13, The region overlapping with transistor 102a provided in the drive circuit section, and the organic insulating film 3 A conductive film 319b, which is formed simultaneously with the conductive film 319, may be provided on 17. 9b can be any potential, such as common potential or ground potential. Dual gate structure By providing a conductive film 319b that overlaps with transistor 102a, The electric field generated by the voltage applied to the conductive film 316d, which functions as the gate electrode, is conducted The film 319b can be shielded. As a result, the orientation of the liquid crystal layer 321 due to the electric field is impaired. It can prevent good.

[0255] <Variation 3> In Embodiment 2 or Embodiment 3, the drive circuit section and the pixel section are inscribed with an organic insulating film 317. A liquid crystal display device having the organic insulating film 31 is described, but as shown in Figure 14, only the pixel portion is covered with the organic insulating film 31. 7a may be provided.

[0256] Furthermore, in the liquid crystal display device shown in Figure 14, the insulating film 313 is formed as shown in Figure 7(B). After that, a mask is formed by patterning, and the insulating film 305, 3 Etch 06, 312, and 313 respectively to form openings. Next, Figure 8(A) After forming the conductive film 315 shown in Figure 8(B), the conductive film 316b shown in Figure 8(B) is formed simultaneously Then, a conductive film 316a is formed connecting the conductive film 304b and the conductive film 310c. After this, An organic insulating film 317a and a conductive film 319 are formed.

[0257] Furthermore, as shown in Figure 15, if the organic insulating film 317a is not provided in the drive circuit section, the dual On the conductive film 316d which functions as the gate electrode of transistor 102b with a double gate structure, A conductive film 319a formed simultaneously with the conductive film 319 may also be provided.

[0258] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0259] (Embodiment 4) In this embodiment, a semiconductor device, which is one aspect of the present invention, will be described with reference to the drawings. .

[0260] Figure 16 shows a cross-sectional view of the transistor 103 and the capacitive element 105 of the semiconductor device. .

[0261] The transistor 103 shown in Figure 16(A) is a gate electrode provided on the substrate 302. A conductive film 304c that functions in this way, and a gate insulating film formed on the substrate 302 and the conductive film 304c. The film 51 and the oxide semiconductor film 308b overlapping the conductive film 304c via the gate insulating film 51. And a pair of electrodes that function as source and drain electrodes, in contact with the oxide semiconductor film 308b. It has conductive films 310d and 310e.

[0262] Furthermore, a metal oxide film 308c is provided on the gate insulating film 51. The physical film 308c is one of the conductive films 310e of the pair of conductive films included in the transistor 103. Connect them. Also, an inorganic insulating film 53 is placed on the transistor 102 and the metal oxide film 308c. A conductive film 316b is provided on the inorganic insulating film 53. A metal oxide film 308c is provided. The capacitive element 105 is composed of an inorganic insulating film 53 and a conductive film 316b.

[0263] Furthermore, an organic insulating film 317 is provided on the inorganic insulating film 53 and the conductive film 316b. Furthermore, in the openings provided in the inorganic insulating film 53 and the organic insulating film 317, the conductive film 310e A conductive film 319 that connects to the pixel is provided on the organic insulating film 317. The conductive film 319 is provided on the organic insulating film 317. It functions as a pole.

[0264] The metal oxide film 308c is an oxide semiconductor film formed simultaneously with the oxide semiconductor film 308b. In addition, hydrogen, boron, phosphorus, nitrogen, tin, antimony, noble gas elements, alkali metals, alkaline By introducing impurities such as earth metals or oxygen deficiencies, conductivity is improved, and conductivity is achieved. It becomes a transparent film. Furthermore, since oxide semiconductor films are transparent, the metal oxide film 308c is also transparent. It is photosensitive.

[0265] Furthermore, conductive films 316b and 319 are formed from transparent conductive films. Therefore, the capacitive element 105 is light-transmitting. For this reason, the area of ​​the capacitive element in the pixel is increased. It is possible to increase the capacitance value of the capacitive element and the aperture ratio of the pixel. .

[0266] Furthermore, 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, via the inorganic insulating film 53 and the organic insulating film 317. Then it is connected to transistor 103. That is, the conductive film 319 is at a distance from transistor 103. Because of the distance between them, the potential of the conductive film 310d of transistor 103 is less likely to affect it. As a result, it is possible to superimpose the conductive film 319 with the transistor 103, and the pixel opening This can increase the percentage of votes.

[0267] The transistor 103 shown in this embodiment in Figure 16 is an organic insulating film on an inorganic insulating film 53. It has a film 317. The organic insulating film 317 has a thickness of 500 nm or more, and because it is thick, The electric field is generated when a negative voltage is applied to the conductive film 304c, which functions as a electrode. The effect does not extend to the surface of the organic insulating film 317, and a positive charge remains on the surface of the organic insulating film 317. It is less prone to static charge. Also, the organic insulating film 317 has a thickness of 500 nm or more, and because it is thick, air Even if positively charged particles contained in the air are adsorbed onto the surface of the organic insulating film 317, the organic insulating film 31 The electric field of positively charged particles adsorbed on the surface of 7 is transmitted to the oxide semiconductor film 308b and the inorganic insulating film 53 The interface is less affected. As a result, the oxide semiconductor film 308b and the inorganic insulating film 53 At the interface, a substantially positive bias is not applied, and the transistor threshold The fluctuation in the voltage value is small.

[0268] Furthermore, in the organic insulating film 317, water and other substances diffuse easily, but the inorganic insulating film 53 is nitride By having an insulating film, the nitride insulating film acts as a barrier film for water, which then diffuses into the organic insulating film 317. It is possible to prevent the water from diffusing into the oxide semiconductor film 308b.

[0269] From the above, by providing the organic insulating film 317 on the transistor, the transistor It is possible to reduce variations in electrical characteristics. Furthermore, it has normally-off characteristics, and reliability Highly reliable transistors can be fabricated. Furthermore, organic insulating films can be produced by printing or coating methods. Since it can be formed using the above, the manufacturing time can be shortened. By providing a conductive film that functions as a pixel electrode on the organic insulating film 317, the opening in the pixel This can increase the percentage of votes.

[0270] <Example 1> A modified version of the transistor shown in Figure 16(A) will be explained using Figure 16(B). The transistor 103 shown in this modified example is an oxide semiconductor film formed using a multi-gradation mask. It is characterized by having 308e and a pair of conductive films 310f and 310g. The zista 103 and the capacitive element 105 are connected by a conductive film 319 that functions as a pixel electrode. It is characterized by being present.

[0271] Furthermore, in Figure 16(B), the metal oxide film 308f is formed on the gate insulating film 51. Furthermore, conductive films 310f and 310g are formed simultaneously on the metal oxide film 308f. The conductive film 310h is present. Also, the conductive film 319 is in contact with the conductive film 310g and the conductive film 310h. Continued. As a result, transistor 103 and capacitive element 105 are electrically connected. Also, As shown in Figure 16(C), the channel-protected transistor 103d and the capacitive element 105 However, they may be connected by a conductive film 319 that functions as a pixel electrode.

[0272] <Modification 2> In the display device shown in Embodiment 4, depending on the circumstances, for example, Alternatively, the conductive film 319 may be formed using a conductive film that has the function of reflecting light.

[0273] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0274] (Embodiment 5) In this embodiment, drawings illustrate a semiconductor device and a method for manufacturing the same, which are aspects of the present invention. Refer to the explanation.

[0275] In this embodiment, a display device is shown as an example of a semiconductor device. The structure of the display device and Figure 2 can be used as appropriate for the circuit diagram of each pixel.

[0276] This section describes the specific configuration of the element substrate included in the display device. A VA-type liquid crystal display device is used, and a top view of the pixels 301 included in the liquid crystal display device is shown. This is shown in 17.

[0277] In Figure 17, the conductive film 304c, which functions as a scanning line, is a conductive film that functions as a signal line. It is provided extending in a direction approximately perpendicular to the membrane (left-right direction in the diagram). It functions as a signal line. The conductive film 310d extends in a direction substantially perpendicular to the conductive film that functions as a scanning line (up and down direction in the figure). It is extended and installed.

[0278] Transistor 103 has a conductive film that functions as a scanning line and a conductive film that functions as a signal line. It is located in the region where they intersect. Transistor 103 functions as a gate electrode. Electrode film 304c, gate insulating film (not shown in Figure 17), and a char formed on the gate insulating film. The oxide semiconductor film 308b, in which the Nell region is formed, functions as the source electrode and drain electrode. It is composed of a pair of conductive films 310d and 310e.

[0279] Furthermore, the metal oxide film 308c is connected to the conductive film 310e contained in the transistor 103. Furthermore, a conductive film 316b is provided on the metal oxide film 308c via an insulating film. In addition, in the insulating film provided on the metal oxide film 308c, the dashed line indicates An opening 362 is provided. In the opening 362, the metal oxide film 308c is an insulating It comes into contact with the nitride insulating film (not shown in Figure 17) contained in the edge film.

[0280] Capacitive element 105 is formed in the region where the metal oxide film 308c and the conductive film 316b overlap. The metal oxide film 308c and the conductive film 316b are light-transmitting. That is, the capacitive element 105 It is translucent.

[0281] The conductive film 319, which functions as a pixel electrode, is connected via an organic insulating film (not shown in Figure 17). , provided on conductive film 310e and conductive film 316b. Also, conductive film 319 is provided on opening 3 It is connected to the conductive film 310e at 64c. That is, transistor 103, capacitive element 1 05 and the conductive film 319 are electrically connected.

[0282] Next, Figure 18 shows a cross-sectional view between the dashed lines C and D in Figure 17. Note that in Figure 18... The drive circuit section includes the scan line drive circuit 14 and the signal line drive circuit 16 (top view omitted). A cross-sectional view of the .) is shown at AB. In this embodiment, the semiconductor device is a VA type This section will explain liquid crystal display devices.

[0283] The liquid crystal display device shown in this embodiment has liquid crystals between a pair of substrates (substrate 302 and substrate 342). Element 322 is being held in place.

[0284] The liquid crystal element 322 has a conductive film 316b on top of the substrate 302 and a film that controls the orientation (hereinafter It has an alignment film 320, 352, a liquid crystal layer 321, and a conductive film 350.

[0285] In the drive circuit section, the conductive film 304a and gate insulating film 51 function as gate electrodes. insulating film 305 and insulating film 306 that function as such, and an oxide semiconductor film in which a channel region is formed. 308a, conductive films 310a and 310b that function as source and drain electrodes The transistor 102 is formed by the oxide semiconductor film 308a, which is provided on the gate insulating film 51. It is possible.

[0286] In the pixel portion, the conductive film 304c functions as the gate electrode, and the gate insulating film 51 is Functional insulating film 305 and insulating film 306, channel region formed on gate insulating film 51 The oxide semiconductor film 308b formed thereon, and the conductive material that functions as the source electrode and drain electrode. The films 310d and 310e constitute the transistor 103. The oxide semiconductor film 308b is , provided on the gate insulating film 51. Also, inorganic insulating film is provided on the conductive films 310d and 310e. The insulating film 312 and insulating film 314, which constitute the film 53, are provided as protective films.

[0287] Furthermore, the metal oxide film 308c functions as one electrode, and the insulating film functions as a dielectric. The capacitive element 105 is composed of film 314 and conductive film 316b, which functions as the other electrode. The metal oxide film 308c is provided on the gate insulating film 51.

[0288] An organic insulating film 317 is formed on the inorganic insulating film 53. Furthermore, on the organic insulating film 317, A conductive film 319 that functions as a pixel electrode is formed. Metal oxide film 308c and conductive film 3 19 is connected by a conductive film 310e.

[0289] Furthermore, in the drive circuit section, the conductive film 30 formed simultaneously with the conductive films 304a and 304c 4b and conductive film 31 formed simultaneously with conductive films 310a, 310b, 310d, and 310e 0c is connected by the conductive film 319a, which is formed simultaneously with the conductive film 319.

[0290] Conductive films 304a and 319a are insulating films 305, 306, and 312. The connections are made at openings provided in the organic insulating film 317. The film 319a is an opening provided in the insulating film 312, insulating film 314, and organic insulating film 317. Connect in the section.

[0291] Although not shown in the diagram, the conductive film 316b was formed simultaneously with the conductive films 319 and 319a. Conductive films formed simultaneously with conductive films 304a, 304b, and 304c, or Conductive films 310a, 310b, 310c, 310d, and 310e formed simultaneously with conductive films Electrically connected. Also, conductive films 304a, 304b, and 304c formed simultaneously. The film, or conductive films 310a, 310b, 310c, 310d, and 310e, are formed simultaneously. Any potential, such as common potential or ground potential, is applied to the conductive film 316b through the conductive film. .

[0292] The components of the display device shown in Figure 18 will be described below.

[0293] Conductive films 304a, 304b, and 304c are formed on the substrate 302. 04a functions as the gate electrode of the transistor in the drive circuit section. Also, the conductive film... 304b is formed in the drive circuit section and connects to the conductive film 310c. Also, the conductive film 304c It is formed in the pixel portion 11 and functions as the gate electrode of the transistor in the pixel portion.

[0294] On the substrate 302 and the conductive films 304a, 304c, and 304b, there is an insulating film 305, an insulating film 306 is formed. The insulating film 305 and insulating film 306 are the transistor of the drive circuit section. The gate insulating film 51 and the gate insulating film 51 of the transistor in the pixel section 11 have functions as such. do.

[0295] On the insulating film 306, oxide semiconductor films 308a, 308b, and a metal oxide film 308c are formed The oxide semiconductor film 308a is formed in a position where it overlaps with the conductive film 304a. It functions as the channel region of the transistor in the drive circuit section. Also, oxide semiconductor film 308 b is formed in a position overlapping with the conductive film 304c, and is the channel region of the transistor in the pixel area. It functions as follows. The metal oxide film 308c is a conductive film 310 included in the transistor 103. It is connected to e and functions as an electrode for the capacitive element 105.

[0296] In the liquid crystal display device shown in this embodiment, the capacitive elements are light-transmitting. As a result, the capacitive elements This allows for increasing the area occupied by the child while also increasing the aperture ratio of the pixels.

[0297] insulating film 306, oxide semiconductor films 308a, 308b, metal oxide film 308c, and conductive On films 310a, 310b, 310c, 310d, and 310e, an inorganic insulating film 53 is provided. Insulating film 312 and insulating film 314 are formed.

[0298] The conductive film 316b is formed on the insulating film 314 and functions as an electrode of a capacitive element. can.

[0299] An organic insulating film 317 is formed on the inorganic insulating film 53 and the conductive film 316b.

[0300] Furthermore, conductive films 319 and 319a are formed on the organic insulating film 317. 19 functions as a pixel electrode. The conductive film 319a is located at the opening 364a (see Figure 22(A)). In the opening 364b (see Figure 22(A)), the conductive film 310a is electrically connected, and the opening 364b is electrically connected. .) is electrically connected to conductive film 310c. That is, conductive film 304a and conductive film 3 It functions as a connecting electrode for 10c.

[0301] Furthermore, in order to create a connection structure in which conductive film 304a and conductive film 310c are in direct contact, Before forming the film 310c, in order to form openings in the insulating film 305 and insulating film 306, Turning is required to form a mask. However, as shown in Figure 18, conductive By connecting the conductive film 304a and the conductive film 310c with film 319a, the conductive film 304 This eliminates the need to fabricate a connection point where a and the conductive film 310c are in direct contact, and the photomask can be reduced to 1 The number of sheets can be reduced. In other words, it is possible to reduce the manufacturing process of liquid crystal display devices. .

[0302] The alignment film 320 is preferably translucent, and is typically made of acrylic resin. Organic resins such as polyimide and epoxy resin can be used.

[0303] Furthermore, a colored film 346 is formed on the substrate 342. The colored film 346 is a color film. It functions as a filter. In addition, the light-shielding film 344 adjacent to the colored film 346 is on the substrate 342 A light-shielding film 344 is formed on top. The light-shielding film 344 functions as a black matrix. Also, a colored film 3 46 is not necessarily required, and may be omitted depending on the case of a monochrome liquid crystal display, for example. A configuration without a color film 346 is also possible.

[0304] Furthermore, an insulating film 348 is formed on the colored film 346. The insulating film 348 is planarized It functions as a layer, or it suppresses the diffusion of impurities that the colored film 346 may contain to the liquid crystal element. It has the function of controlling.

[0305] Furthermore, a conductive film 350 is formed on the insulating film 348. The conductive film 350 is formed on the pixel portion It functions as the other of the pair of electrodes that the liquid crystal element has. Note that conductive films 319, 31 An orientation film 352 is formed on 9a and the conductive film 350.

[0306] Furthermore, a liquid crystal layer 321 is formed between the conductive films 319, 319a and the conductive film 350. Furthermore, the liquid crystal layer 321 is sealed using a sealing material (not shown) between substrate 302 and substrate 342. It is sealed between them. The sealing material is used to prevent moisture and other substances from entering from the outside. A configuration in which it comes into contact with an inorganic material is preferred.

[0307] Furthermore, the thickness of the liquid crystal layer 321 (cell gear) is between the conductive films 319, 319a and the conductive film 350. A spacer (also called a top) may be provided to maintain the position.

[0308] The method for manufacturing the element portion provided on the substrate 302 shown in the liquid crystal display device in Figure 18. This will be explained using Figures 5, 19, and 21.

[0309] Similar to Embodiment 2, the following steps are taken on the substrate 302: Electromagnetic films 304a, 304b, 304c, insulating film 305, insulating film 306, and island-shaped oxides Semiconductor films 308a, 308b, and 308d are formed. Conductive films 304a, 304b, and 304c are formed by the formation and etching process. Furthermore, the second patterning process forms a mask and the etching process is performed, They form body membranes 308a, 308b, and 308d.

[0310] Furthermore, after this, a heat treatment is performed in the same manner as in Embodiment 2 to obtain the oxide semiconductor film 308a. By removing hydrogen, water, etc. contained in 308b and 308d, oxide semiconductor films 308a and 308... b. The hydrogen and water concentrations in 308d may be reduced. As a result, the purity is increased. The oxide semiconductor films 308a, 308b, and 308d can be formed. The temperature is typically between 250°C and 650°C, preferably between 300°C and 500°C. The temperature of the heat treatment is typically 300°C to 400°C, preferably. By keeping the temperature between 320°C and 370°C, warping and shrinkage of the substrate are prevented even on large-area substrates. This makes it possible to reduce waste and improve yield.

[0311] Furthermore, if the film deposition temperature of the insulating film 311a that is formed later is set to be between 280°C and 400°C... In addition, hydrogen, water, etc. contained in the oxide semiconductor films 308a, 308b, and 308d are removed. Since this is possible, the heat treatment is unnecessary.

[0312] Next, similar to Embodiment 2, insulating film 306 and oxide semiconductor films 308a, 308b A conductive film 309 is formed on 308d (see Figure 19(A)).

[0313] Next, similar to Embodiment 2, the conductive film 309 is processed into a desired shape, thereby creating the conductive film 3 Form 10a, 310b, 310c, 310d, and 310e. Note that conductive film 310a, 310b, 310c, 310d, and 310e are made into the desired shape by a third patterning process. The mask is formed by creating a screen and etching the areas not covered by the mask. This can be done (see Figure 19(B)). Note that the conductive film 310e is the oxide semiconductor film 308b It is also in contact with the oxide semiconductor film 308d.

[0314] Next, similar to Embodiment 2, insulating film 306, oxide semiconductor films 308a, 308b, 3 08d, and the conductive films 310a, 310b, 310c, 310d, and 310e are covered with This forms an insulating film 311 by stacking insulating films 311a and 311b (see Figure 19(C)). The insulating film 311 can be formed using sputtering, CVD, vapor deposition, etc. Cut.

[0315] Next, a heat treatment is performed in the same manner as in Embodiment 2. The temperature of this heat treatment is typically 1 50°C or higher but below the substrate strain point, preferably 200°C or higher but 450°C or lower, more preferably 30 The temperature shall be between 0°C and 450°C. Typically, the temperature of this heat treatment is between 300°C and 450°C. By setting the temperature to below 0°C, preferably between 320°C and 370°C, even large-area substrates can be processed. This makes it possible to reduce warping and shrinkage of the circuit board, improving yield.

[0316] This heat treatment removes some of the oxygen contained in the insulating film 311b from the oxide semiconductor film 308a. , move to 308b and 308d, and the oxide semiconductor films 308a, 308b and 308d are contained within them. It is possible to reduce the amount of oxygen vacancy. As a result, oxide semiconductor films 308a, 30 The amount of oxygen deficiency in 8b and 308d can be further reduced.

[0317] Furthermore, if the insulating films 311a and 312b contain water, hydrogen, etc., the water, hydrogen, etc. can be blocked. An insulating film 313 having a coating function is subsequently formed and heat treatment is performed, and the insulating film 311a, Water, hydrogen, etc. contained in 311b migrate to oxide semiconductor films 308a, 308b, and 308d. As a result, defects occur in the oxide semiconductor films 308a, 308b, and 308d. By heating, water, hydrogen, etc. contained in the insulating films 311a and 311b are removed. This is possible, reducing variations in the electrical characteristics of transistors and also reducing fluctuations in the threshold voltage. It can be suppressed.

[0318] Furthermore, by forming the insulating film 311b on the insulating film 311a while heating, oxide semiconductors Oxygen is transferred to the body membranes 308a, 308b, and 308d, and oxide semiconductor films 308a, 308 Since it is possible to reduce the amount of oxygen deficiency contained in b, 308d, this heat treatment is performed. You don't have to.

[0319] The heat treatment may be performed after the opening 362, which is formed later, has been created.

[0320] Next, similar to Embodiment 2, the insulating film 311 is processed into a desired shape, 12 and the opening 362 are formed. Note that the insulating film 311 and the opening 362 are desired A mask is formed on the shape by a fourth patterning, and the area not covered by the mask is It can be formed by etching (see Figure 20(A)).

[0321] The opening 362 is formed so that the surface of the oxide semiconductor film 308d is exposed.

[0322] Next, similar to Embodiment 2, the insulating film 312 and the oxide semiconductor film 308d are placed on the insulating film 3 Forms 13 (see Figure 20(B)).

[0323] Next, similar to Embodiment 2, a conductive film 315 is formed on the insulating film 314 (Figure 21(A )reference.).

[0324] Next, the conductive film 315 is processed into the desired shape to form 316b. The film 316b is subjected to a fifth patterning process to form a mask in the desired shape, and the mask It can be formed by etching the uncovered areas (see Figure 21(B)). ).

[0325] Next, an organic insulating film 317 is formed to cover the insulating film 314 and the conductive film 316b (Figure 2). See 1(C). The organic insulating film 317, which functions as a planarizing film, is a conductive film of the insulating film 313 and Each of the membranes 316b has an opening so that a portion of it is exposed.

[0326] Next, using the organic insulating film 317 as a mask, insulating film 305, insulating film 306, insulating film 312 and a portion of the insulating film 313 are etched to expose the conductive film 304b. 364a, an opening that exposes the conductive film 310c, 364b, an opening that exposes the conductive film 310e It forms 364c (see Figure 22(A)).

[0327] Next, a conductive film 318 is formed in the same manner as in Embodiment 2 (see Figure 22(B)).

[0328] Next, similar to Embodiment 2, the conductive film 318 is processed into a desired shape, thereby creating the conductive film 3 19 and 319a are formed. The conductive films 319 and 319a are formed into a seventh pattern in the desired shape. A mask is formed by etching, and the areas not covered by the mask are etched. It can be formed by (see Figure 22(C)).

[0329] In the above steps, a pixel section having a transistor and a drive circuit section are formed on the substrate 302. This is possible. In addition, in the manufacturing process shown in this embodiment, the first to seventh patterns This refers to the process of simultaneously forming transistors and capacitive elements using seven photomasks. It is possible.

[0330] Furthermore, the element portion provided on the substrate 342, which is provided opposite the substrate 302, is in the form of The product can be formed by appropriately using the manufacturing process shown in Figure 10, which is shown in State 2.

[0331] Next, similar to Embodiment 2, on substrates 302 and 342, more specifically on substrate 302 An insulating film 314, conductive films 319, 319a formed on the substrate 342, and conductive films formed on the substrate 342 Alignment film 320 and alignment film 352 are formed on film 350, respectively. Then, substrate 302 and A liquid crystal layer 321 is formed between the substrate 342 and the liquid crystal layer 321.

[0332] By following the above steps, the liquid crystal display device shown in Figure 18 can be manufactured.

[0333] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0334] (Embodiment 6) In this embodiment, we describe a liquid crystal display device having a different transistor than that of Embodiment 4. This will be explained using Figures 23 to 27.

[0335] The liquid crystal display device shown in Figure 23 has a dual gate structure in the drive circuit section shown AB. It is characterized by having transistor 102a.

[0336] The transistor 102a provided in the drive circuit section is the same as the transistor 1 shown in Embodiment 2. It has the same structure as 02a.

[0337] <Example 1> The liquid crystal display device shown in Figure 23 of Embodiment 6 uses a dual transistor in the drive circuit section. Although it is fabricated using an algate structure transistor, as shown in Figure 24, AB The drive circuit shown has a dual-gate transistor 102a, and CD A dual-gate transistor 103a may be used in the pixel section shown.

[0338] Transistor 103a has a structure similar to that of transistor 103a shown in Embodiment 2. do.

[0339] Along with the drive circuit section, the pixel section has high reliability, high on-current, and high field-effect mobility. By incorporating a dual-gate transistor structure, a liquid crystal display device with superior display quality can be created. It can be manufactured.

[0340] <Modification 2> In the liquid crystal display device shown in Embodiment 5 or Embodiment 6, as shown in Figure 25, The region overlapping with transistor 102a provided in the drive circuit section, and the organic insulating film 3 A conductive film 319b, which is formed simultaneously with the conductive film 319, may be provided on 17. 9b can be any potential, such as common potential or ground potential. Dual gate structure By providing a conductive film 319b that overlaps with transistor 102a, The electric field generated by the voltage applied to the conductive film 316d, which functions as the gate electrode, is conducted The film 319b can be shielded. As a result, the orientation of the liquid crystal layer 321 due to the electric field is impaired. It can prevent good.

[0341] <Variation 3> In Embodiment 5 or Embodiment 6, the drive circuit section and the pixel section are inscribed with an organic insulating film 317. A liquid crystal display device having the organic insulating film 31 was described, but as shown in Figure 26, only the pixel portion is covered with the organic insulating film 31. 7a may be provided.

[0342] Furthermore, as shown in Figure 27, if the organic insulating film 317a is not provided in the drive circuit section, the dual On the conductive film 316d which functions as the gate electrode of transistor 102b with a double gate structure, A conductive film 319a formed simultaneously with the conductive film 319 may also be provided.

[0343] <Modification 4> In Embodiments 5 and 6, a liquid crystal element is used as an example of a display element. As explained above, various display elements can be used. For example, an organic EL element can be used. Examples of this case are shown in Figures 28, 29, 30, and 31. Display with organic EL elements The apparatus includes organic resin films 371 such as acrylic resin, polyimide, and epoxy resin, and organic resin films 3 The EL layer 373 is provided on 71, and a common electrode 375 is provided on the EL layer 373. Furthermore, the conductive film 319, the EL layer 373, and the common electrode 375 constitute the organic EL element. To accomplish.

[0344] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0345] (Embodiment 7) In this embodiment, Embodiments 2 and 3, Embodiments 4 and 5 In comparison, the process uses one more photomask, i.e., eight photomasks. A liquid crystal display device having transistors and capacitive elements will be explained using Figure 32.

[0346] The liquid crystal display device shown in Figure 32 has an opening 36 provided in the insulating film 312 and the insulating film 314. In 3, the conductive film 316b and the conductive film 310e contained in the transistor 103 are conductive It is characterized by being connected to the membrane 319.

[0347] In this embodiment, the liquid crystal display device has a transistor 103 and a capacitive element 105 connected. An opening for this purpose connects to the transistor 103 and the conductive film 319 which functions as a pixel electrode. The opening overlaps with the conductive film 310e contained in transistor 103. The conductive film 316b contained in the element 105 connects to an opening, and the transistor 103 contains The opening through which the conductive film 310e and the conductive film 319, which functions as a pixel electrode, are connected overlaps. Therefore, it is possible to increase the aperture ratio at each pixel.

[0348] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0349] (Embodiment 8) In this embodiment, the transistor has a different structure from the transistors shown in Embodiments 2 to 7. A liquid crystal display device having transistors will be explained using Figures 33 to 37.

[0350] The liquid crystal display device shown in Figure 33 is compared to the liquid crystal display devices shown in Embodiments 2 to 7. In contrast, it differs in that it uses channel-protected transistors.

[0351] The liquid crystal display device shown in Figure 33 is compared to the liquid crystal display devices shown in Embodiments 2 to 7. In contrast, at the opening of the insulating film 392, the oxide semiconductor film 308a and the conductive film 310a, 310b is connected, and the oxide semiconductor film 308b and the conductive films 310d and 310e are connected. The difference lies in the presence of an insulating film 394 between the insulating film 314 and the conductive film 316b. The point is different.

[0352] In the drive circuit section, the conductive film 304a and gate insulating film 51 function as gate electrodes. insulating film 305 and insulating film 306 that function as such, and an oxide semiconductor film in which a channel region is formed. 308a, insulating film 392 covering the oxide semiconductor film 308a, at the opening of the insulating film 392 A conductive film 31 that is in contact with the oxide semiconductor film 308a and functions as a source electrode and a drain electrode. 0a and 310b constitute the transistor 102c. Also, conductive films 310a and 310 Insulating films 312, 314, and 394 are provided on b and 310c. .

[0353] In the pixel area, the conductive film 304c functions as a gate electrode, and the gate insulating film functions as a gate insulating film. Insulating film 305 and insulating film 306, and a channel region formed on the gate insulating film are formed an oxide semiconductor film 308b, an insulating film 392 covering the oxide semiconductor film 308b, insulating film 39 At the opening 2, it is in contact with the oxide semiconductor film 308b, and serves as the source electrode and drain electrode. The functional conductive films 310d and 310e constitute the transistor 103b. Insulating films 312, 314, and 394 are provided on films 310d and 310e. It is being done.

[0354] Furthermore, the conductive film 316b is provided on the insulating film 314.

[0355] Furthermore, the metal oxide film 308c functions as an electrode, and the insulating film 31 functions as a dielectric film. The capacitive element 105 is composed of 4, an insulating film 394, and a conductive film 316b that functions as an electrode. ru.

[0356] Since the insulating film 392 is in contact with the oxide semiconductor films 308a and 308b, the oxide insulating film forms It is preferable that the insulating film 392 be formed using the same material as the insulating film 306. This is possible. In addition, the insulating film 392 is an oxide insulating film that permeates oxygen, similar to the insulating film 312a. It is preferable that it be a film with a small number of defects. As a result, the oxygen contained in the insulating film 312b It is possible to move the oxide semiconductor film 308a, 308b, and oxide semiconductor film 30 It is possible to reduce the amount of oxygen vacancies contained in 8a and 308b. It is preferable to have a small number of defects at the interface between films 308a and 308b and the insulating film 392.

[0357] The insulating film 394 is provided to control the capacitance value of the capacitive element 105. Therefore, the insulating film 394 can be formed using an oxide insulating film or a nitride insulating film as appropriate. Also, The insulating film 394 was formed by CVD (chemical vapor deposition) using organic silane gas. By using an oxide insulating film, typically a silicon oxide film, it is possible to improve flatness. This is preferable. Furthermore, the insulating film 314 prevents the capacitive element 105 from obtaining a predetermined capacitance value. If possible, the insulating film 394 does not need to be provided.

[0358] In this modified example, the oxide semiconductor films 308a and 308b are covered by the insulating film 392. Therefore, by etching, conductive films 310a, 310b, 310d, and 310e are formed. Furthermore, the oxide semiconductor films 308a and 308b are not damaged. In addition, the insulating film 312 is It is formed from an oxide insulating film containing more oxygen than satisfactorily satisfying the stoichiometric composition. Therefore, some of the oxygen contained in the insulating film 312 is transferred to the oxide semiconductor films 308a and 308b. This makes it possible to reduce the amount of oxygen vacancies contained in the oxide semiconductor films 308a and 308b.

[0359] An organic insulating film 317 is provided on the insulating film 394 and the conductive film 316b.

[0360] Furthermore, conductive films 319 and 319a are formed on the organic insulating film 317. 19 functions as a pixel electrode. The conductive film 319a is located at the opening 364a (see Figure 36(C)). In the opening 364b (see Figure 36(C)), the conductive film 310a is electrically connected, and the opening 364b is electrically connected. .) is electrically connected to conductive film 310c. That is, conductive film 304a and conductive film 3 It functions as a connecting electrode for 10c.

[0361] The method for manufacturing the element portion provided on the substrate 302 shown in the liquid crystal display device in Figure 33. This will be explained using Figures 5, 34 to 36.

[0362] Similar to Embodiment 1, the process shown in Figures 5(A) to 5(C) is followed, and the material is applied to the substrate 302. Conductive films 304a, 304b, and 304c function as gate electrodes, and function as gate insulating films. The insulating film 305 and insulating film 306, and oxide semiconductor films 308a, 308b, and 308d are formed To accomplish this. In addition, in the said process, the first patterning and the second patterning are performed. Conductive films 304a, 304b, 304c and oxide semiconductor films 308a, 308b, 3 It forms 08d.

[0363] Next, as shown in Figure 34(A), an insulating film 390 is formed. It is formed using the same conditions as for 305 or insulating film 311a.

[0364] Next, by processing the insulating film 390 into the desired shape, an opening is formed as shown in Figure 34(B). An insulating film 392 is formed having portions 391, 391a, 391b, 391c, and 391d. Furthermore, the insulating film 392 is formed by creating a mask in the desired shape by a third patterning, It can be formed by etching the areas not covered by the mask.

[0365] Next, after forming conductive films on the oxide semiconductor films 308a, 308b and the insulating film 392, , conductive films 310a, 310b, 310c, 310d, 3 are formed through the same process as in Embodiment 1. Form 10e (see Figure 34(C)). Note that conductive films 310a, 310b, and 310c are also formed. 310d and 310e are used to form a mask in the desired shape by a fourth patterning process. This can be formed by etching the areas not covered by the mask.

[0366] Next, insulating film 392 and conductive films 310a, 310b, 310c, 310d, 310e An insulating film 311 is formed on top (see Figure 35(A)).

[0367] Next, the insulating film 311 is processed into a desired shape, thereby creating an insulating film 31 having an opening 393. Form 2. Note that the insulating film 312 and the opening 393 are made into a fifth pattern in the desired shape. A mask is formed using a etchant, and the areas not covered by the mask are etched to create a shape. This can be achieved (see Figure 35(B)).

[0368] Next, as shown in Figure 35(C), the oxide semiconductor film 308d, the insulating film 392 and the opening Insulating film 313 and insulating film 394 are formed to cover 393.

[0369] The insulating film 394 is formed using methods such as CVD or sputtering.

[0370] Next, after forming a conductive film on the insulating film 394, the same process as in Embodiment 1 is followed to form a conductive film Form 316b (see Figure 36(A)). Note that the conductive films 316a and 316b are as desired. A mask is formed by a sixth patterning process in the shape of the mask, and the area not covered by the mask It can be formed by etching.

[0371] Next, as shown in Figure 36(B), an organic insulating film 317 is formed in the same manner as in Embodiment 2. The organic insulating film 317 is photolithographed using the sixth photomask shown in Embodiment 2. It can be formed using the same process as the FI process. In this embodiment, This process corresponds to the seventh patterning step.

[0372] Next, using the organic insulating film 317 as a mask, insulating film 305, insulating film 306, insulating film 312 A portion of the insulating film 313 and insulating film 394 is etched to create the conductive film 304b. Exposed opening 364a, conductive film 310c Exposed opening 364b, conductive film 310e An exposed opening 364c and an opening 364d that exposes the conductive film 316b are formed (Figure See 36(C). ).

[0373] Next, after forming the conductive film, conductive films 319 and 319a are formed through the same process as in Embodiment 1. (See Figure 37.) The conductive films 319 and 319a are formed into the desired shape by the eighth pattern. A mask is formed by turning, and the areas not covered by the mask are etched. It can be formed by doing so.

[0374] In the above steps, a pixel section having a transistor and a drive circuit section are formed on the substrate 302. This is possible. In addition, in the manufacturing process shown in this embodiment, the first to eighth patterns This refers to the process of simultaneously forming transistors and capacitive elements using eight photomasks. It is possible.

[0375] In Embodiments 1 to 8, a liquid crystal element is used as an example of a display element. As explained above, various display elements can be used. For example, an organic EL element can be used. Examples of this case are shown in Figures 38, 39, 40, 41, and 42. (The organic EL element is...) The display device is an organic resin film 371 such as acrylic resin, polyimide, epoxy resin, organic It has an EL layer 373 provided on a resin film, and a common electrode 375 provided on the EL layer. Furthermore, the conductive film 319, the EL layer 373, and the common electrode 375 constitute the organic EL element. ru.

[0376] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0377] (Embodiment 9) Transistors 102, 102a, 102b, 10 shown in Embodiments 2 to 8 In 2c, 103, 103a, and 103b, the oxide semiconductor film is stacked as needed. This can be done. Here, we will explain using transistor 103.

[0378] The transistor shown in Figure 43 has an acid between the insulating film 306 and the conductive films 310d and 310e. A multilayer film 336 containing a synthetic semiconductor film is formed.

[0379] The multilayer film 336 has an oxide semiconductor film 336a and an oxide semiconductor film 336b. The multilayer film 336 has a two-layer structure. In addition, a portion of the oxide semiconductor film 336a is a channel region. It functions as such. In addition, an insulating film 312a is formed so as to be in contact with the multilayer film 336. An oxide semiconductor film 336b is formed so as to be in contact with the insulating film 312a. An oxide semiconductor film 336b is provided between the material semiconductor film 336a and the insulating film 312a. ru.

[0380] The oxide semiconductor film 336b is composed of one or more of the elements that make up the oxide semiconductor film 336a. The oxide semiconductor film 336b is made up of one of the elements that make up the oxide semiconductor film 336a. Because it is constructed from above, at the interface between the oxide semiconductor film 336a and the oxide semiconductor film 336b Therefore, interfacial scattering is less likely to occur. Consequently, carrier movement is not hindered at the interface. Therefore, the field-effect mobility of the transistor increases.

[0381] Oxide semiconductor films 336b are typically In-Ga oxide films, In-Zn oxide films, In-M-Zn oxide film (where M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn) (or Hf), and the energy at the lower end of the conduction band is lower than that of the oxide semiconductor film 336a. It is close to the energy level, and typically, the energy at the lower end of the conduction band of the oxide semiconductor film 336b, and the oxidation The energy difference from the lower end of the conduction band of the monocrystalline semiconductor film 336a is 0.05 eV or greater, and 0.07 eV or greater. eV or greater, 0.1eV or greater, or 0.15eV or greater and 2eV or less, 1eV or less, 0 It is 0.5 eV or less, or 0.4 eV or less. That is, the electron affinity of the oxide semiconductor film 336b The difference between the force and the electron affinity of the oxide semiconductor film 336a is 0.05 eV or greater, and 0.07 eV. Above 0.1eV, or above 0.15eV and below 2eV, below 1eV, 0.5 It is below eV, or below 0.4 eV.

[0382] The oxide semiconductor film 336b has high carrier mobility (electron mobility) due to the presence of In. It is preferable to become that way.

[0383] The oxide semiconductor film 336b is composed of Al, Ti, Ga, Y, Zr, La, Ce, Nd, and S. Having n or Hf in a higher atomic ratio than In may have the following effects: (1) Increase the energy gap of the oxide semiconductor film 336b. (2) (3) Reduce the electron affinity of the body membrane 336b. (4) Shield against external impurities. Compared to the ionized semiconductor film 336a, it has higher insulating properties. (5) Al, Ti, Ga, Y, Z r, La, Ce, Nd, Sn, or Hf are metallic elements that have a strong bonding force with oxygen, therefore acid This reduces the likelihood of missing elements occurring.

[0384] When the oxide semiconductor film 336b is an In-M-Zn oxide, the atomic ratio of In to M is When the sum of In and M is taken as 100 atomic%, In is less than 50 atomic%, M is greater than 50 atomic%, and more preferably In is less than 25 atomic%, Assume that M is greater than 75 atomic percent.

[0385] Furthermore, the oxide semiconductor film 336a and the oxide semiconductor film 336b are In-M-Zn oxide (where M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf) Compared to the monocrystalline semiconductor film 336a, the oxide semiconductor film 336b contains M(Al, Ti, G The atomic ratio of a, Y, Zr, La, Ce, Nd, Sn, or Hf is large, and typically, Compared to the atoms contained in the oxide semiconductor film 336a, the amount is 1.5 times or more, preferably 2 times. More preferably, the atomic ratio is three times higher or more.

[0386] Furthermore, the oxide semiconductor film 336a and the oxide semiconductor film 336b are In-M-Zn oxide (where M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf) The monocrystalline semiconductor film 336b has an atomic ratio of In:M:Zn=x1:y1:z1, and the oxide semiconductor film If 336a is represented as In:M:Zn=x2:y2:z2 [atomic ratio], then y1 / x1 is equal to y2 It is greater than / x2, and preferably y1 / x1 is 1.5 times or more than y2 / x2. More preferably, y1 / x1 is at least twice as large as y2 / x2, and more preferably, y 1 / x1 is more than three times larger than y2 / x2.

[0387] For example, as an oxide semiconductor film 336a, In:Ga:Zn=1:1:1, In:Ga: Use an In-Ga-Zn oxide with an atomic ratio of Zn = 1:1:1.2 or 3:1:2. This is possible. Also, as an oxide semiconductor film 336b, In:Ga:Zn=1:3:n(n (where m is an integer between 2 and 8), 1:6:m (where m is an integer between 2 and 10), or 1:9:6 In-Ga-Zn oxides with the atomic ratio of the above can be used. The atomic ratios of 6a and oxide semiconductor film 336b are, respectively, the above atomic ratios with an error. This includes a variation of plus or minus 20%. Furthermore, in the oxide semiconductor film 336a, the Zn content is... A compound of Ga or higher is preferable as it facilitates the formation of CAAC-OS.

[0388] The oxide semiconductor film 336b, when forming the insulating film 312b that is formed later, It also functions as a damage mitigation film for the conductive film 336a.

[0389] The thickness of the oxide semiconductor film 336b is 3 nm or more and 100 nm or less, preferably 3 nm or more. The wavelength should be 50nm or less.

[0390] Furthermore, the oxide semiconductor film 336b, like the oxide semiconductor film 336a, is, for example, non-single crystal. Structure is also acceptable. Non-single crystal structures include, for example, CAAC-OS(C Axis Al), which will be discussed later. igned Crystalline Oxide Semiconductor), This includes crystalline structures, microcrystalline structures (described later), or amorphous structures.

[0391] Furthermore, in oxide semiconductor films 336a and 336b, the amorphous structure is Region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single crystal structure region A mixed film having two or more types may be formed. The mixed film may, for example, have regions with an amorphous structure, microcrystalline One of the following regions: crystalline structure region, polycrystalline structure region, CAAC-OS region, or single crystal structure region In some cases, the single-layer structure may have two or more regions. Furthermore, the mixed film may have, for example, an amorphous structure. Region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single crystal structure region It may have a layered structure of two or more of the following regions.

[0392] Here, between the oxide semiconductor film 336a and the insulating film 312a, the oxide semiconductor film 336 b is provided. Therefore, between the oxide semiconductor film 336b and the insulating film 312a Even if carrier traps are formed due to impurities and defects, the carrier traps are formed There is a gap between the region being treated and the oxide semiconductor film 336a. As a result, the oxide semiconductor Electrons flowing through film 336a are less likely to be trapped by carrier traps, and the transistor's on-current It is possible to increase the electric field effect mobility. When an electron is trapped in a carrier trap, that electron behaves as a negative fixed charge. However, the threshold voltage of the transistor fluctuates. Because there is a gap between a and the region where the carrier trap is formed, It is possible to reduce electron trapping and reduce fluctuations in the threshold voltage. Cut.

[0393] Furthermore, the oxide semiconductor film 336b can shield against external impurities. This makes it possible to reduce the amount of impurities that migrate from the outside to the oxide semiconductor film 336a. Furthermore, the oxide semiconductor film 336b is less likely to form oxygen vacancies. For these reasons, oxide semiconductors It is possible to reduce the impurity concentration and oxygen deficiency in film 336a.

[0394] Furthermore, the oxide semiconductor film 336a and the oxide semiconductor film 336b are not simply stacked. Rather, a continuous junction (in this case, the energy at the lower end of the conduction band changes continuously between each film). The film is fabricated so that a structure is formed at the interface of each film, including trap centers and recombination centers. The layered structure is designed so that there are no impurities that form defect levels like the following. Impurities are mixed between the layered oxide semiconductor film 336a and oxide semiconductor film 336b. As a result, the continuity of the energy bands is lost, and carriers are trapped at the interface, or re-energized. They combine and then disappear.

[0395] To form continuous bonding, a multi-chamber type film deposition system equipped with a load lock chamber is required. By using a sputtering device, each film is continuously layered without being exposed to the atmosphere. This is necessary. Each chamber in the sputtering apparatus is for the oxide semiconductor film To remove impurities such as water as much as possible, an adsorption-type vacuum pump such as a cryopump is used. Using a pump to perform high vacuum evacuation (5×10 -7 Pa~1×10 -4 It is preferable to do so (up to about Pa). It seems so. Alternatively, you can combine a turbomolecular pump and a cold trap to remove air from the exhaust system. It is preferable to prevent gases, especially those containing carbon or hydrogen, from flowing back into the bar. stomach.

[0396] In Figure 43, the multilayer film 336 is made up of oxide semiconductor film 336a and oxide semiconductor film 3 Although a two-layer structure of 36b was adopted, an oxide semiconductor film 336a was further formed between the insulating film 306 and the oxide semiconductor film 336a. A three-layer structure may be provided with a film similar to the semiconductor film 336b. In this case, the insulating film 306 The thickness of the oxide film provided between the oxide semiconductor film 336a is greater than that of the oxide semiconductor film 336a. Smaller is preferable. The thickness of the oxide film should be 1 nm or more and 5 nm or less, preferably 1 nm or more and 3 nm or less. By setting it to less than nm, it is possible to reduce the fluctuation in the transistor's threshold voltage. ru.

[0397] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0398] (Embodiment 10) In this embodiment, the transistor included in the display device described in the above embodiment is Next, we will describe one embodiment applicable to oxide semiconductor films and metal oxide films. The structure of the oxide semiconductor film described here can be applied to metal oxide films as appropriate. <About the structure of oxide semiconductors> The structure of oxide semiconductors will be described below.

[0399] Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single-crystal oxide semiconductor, CAAC-OS (C Axis Aligned) is used. Crystalline Oxide Semiconductor, Polycrystalline Oxide These include semiconductors, microcrystalline oxide semiconductors, and amorphous oxide semiconductors.

[0400] From another perspective, oxide semiconductors include amorphous oxide semiconductors and other crystalline oxides. They can be divided into semiconductors and crystalline oxide semiconductors. Crystalline oxide semiconductors include single-crystal oxide semiconductors and CAAC- Examples include OS, polycrystalline oxide semiconductors, and microcrystalline oxide semiconductors.

[0401] <caac-os> First, let's explain CAAC-OS. Note that CAAC-OS is referred to as CANC(C- This is called an oxide semiconductor having axis-aligned nanocrystals. It can also be done this way.

[0402] CAAC-OS is an oxide having multiple c-axis oriented crystalline portions (also called pellets). It is a type of semiconductor.

[0403] Transmission Electron Microscope (TEM) A composite analysis image of the bright-field image and diffraction pattern of CAAC-OS (high-angle scope) is obtained. Also called a high-resolution TEM image, when observed, multiple pellets can be identified. On the other hand, in high-resolution TEM images, the boundaries between pellets, i.e., grain boundaries, and It is also said that it is not possible to clearly confirm the grain boundaries. Therefore, CAAC-OS is said to be at the grain boundaries. This means that a decrease in electron mobility caused by this phenomenon is less likely to occur.

[0404] The following describes CAAC-OS observed by TEM. Figure 44(A) The image shows a high-resolution TEM image of the cross-section of CAAC-OS observed from a direction approximately parallel to the sample surface. For observing high-resolution TEM images, spherical aberration correction is necessary. The n Corrector function was used. High-resolution TEM images using spherical aberration correction function were obtained. This is specifically called a Cs-corrected high-resolution TEM image. Acquisition of a Cs-corrected high-resolution TEM image can be done, for example, This is performed using an atomic-resolution analytical electron microscope such as the JEM-ARM200F manufactured by JEOL Ltd. It is possible.

[0405] Figure 44(B) shows an enlarged Cs-corrected high-resolution TEM image of region (1) in Figure 44(A). Figure 44(B) shows that the metal atoms in the pellet are arranged in layers. The arrangement of metal atoms in each layer is the plane (also called the surface to be formed) that forms the CAAC-OS film. Alternatively, it reflects the irregularities of the upper surface and is parallel to the surface or upper surface of the CAAC-OS that is formed on it.

[0406] As shown in Figure 44(B), CAAC-OS has a characteristic atomic arrangement. Figure 44(C Figures 44(B) and 44(C) show characteristic atomic arrangements indicated by auxiliary lines. ) Therefore, the size of each pellet is approximately 1 nm to 3 nm, and pellets It can be seen that the size of the gap caused by the tilt is approximately 0.8 nm. Therefore, Pellets can also be called nanocrystals (nc).

[0407] Here, based on the Cs-corrected high-resolution TEM image, the pellets of CAAC-OS on substrate 5120 are... The arrangement of the 5100 can be schematically represented as a structure resembling stacked bricks or blocks. This is the result (see Figure 44(D)). Between the pellets observed in Figure 44(C) The area where the inclination occurs corresponds to region 5161 shown in Figure 44(D).

[0408] Furthermore, Figure 45(A) shows the plane of CAAC-OS observed from a direction approximately perpendicular to the sample surface. The s-corrected high-resolution TEM images are shown. Regions (1), (2), and (3) in Figure 45(A) are shown. The enlarged Cs-corrected high-resolution TEM images of ) are shown in Figures 45(B), 45(C), and 45(C), respectively. This is shown in Figure 45(D). From Figures 45(B), 45(C), and 45(D), the pellets are It can be confirmed that the metal atoms are arranged in a triangular, square, or hexagonal shape. However, no regularity is observed in the arrangement of metal atoms between different pellets.

[0409] Next, C was analyzed by X-ray diffraction (XRD). Let's discuss AAC-OS. For example, CAAC-OS having an InGaZnO4 crystal. When structural analysis of S is performed using the out-of-plane method, the result is as shown in Figure 46(A). In some cases, a peak may appear near a diffraction angle (2θ) of 31°. This peak is in InGa Since it is attributed to the (009) plane of the ZnO4 crystal, the CAAC-OS crystal is c-axis oriented. It can be confirmed that it possesses this property, and that the c-axis is oriented in a direction approximately perpendicular to the surface to be formed or the upper surface.

[0410] In addition, in the structural analysis using the out-of-plane method of CAAC-OS, 2θ is 31 In addition to the peak near °, a peak may also appear when 2θ is near 36°. The nearby peak indicates that some of the crystals in CAAC-OS do not exhibit c-axis orientation. This shows that a more preferable CAAC-OS is structured using the out-of-plane method. The analysis shows that 2θ shows a peak near 31°, but does not show a peak near 36°.

[0411] On the other hand, in the CAAC-OS, X-rays are incident from a direction approximately perpendicular to the c-axis in an in-plane configuration. Structural analysis using the ne method reveals a peak near 2θ = 56°. This peak corresponds to I It is attributed to the (110) plane of the nGaZnO4 crystal. In the case of CAAC-OS, 2θ is 5 The sample is fixed at approximately 6° and analyzed while rotating it around the normal vector of the sample surface as the axis (φ axis). Even after performing a (φ scan), no clear peak appears, as shown in Figure 46(B). In contrast, with a single-crystal oxide semiconductor of InGaZnO4, if 2θ is fixed to around 56°, then φ When scanned, it is attributed to a crystal plane equivalent to the (110) plane, as shown in Figure 46(C). Six peaks are observed. Therefore, structural analysis using XRD indicates that CAAC-OS is It can be confirmed that the orientation of the a-axis and b-axis is irregular.

[0412] Next, we will explain CAAC-OS analyzed by electron diffraction. For example, InGa For CAAC-OS containing ZnO4 crystals, a probe with a diameter of 300 nm is used parallel to the sample surface. When the electron beam is incident, a diffraction pattern like the one shown in Figure 47(A) (limited field transmitted electron wave) is produced. This diffraction pattern may appear. (Also called a diffraction pattern.) The spot originates from the (009) plane of the crystal. Therefore, electron diffraction also reveals The pellets contained in CAAC-OS have c-axis orientation, and the c-axis is on the surface to be formed or the upper surface. It can be seen that it is oriented in a nearly perpendicular direction. On the other hand, for the same sample, when the probe is directed perpendicular to the sample surface... Figure 47(B) shows the diffraction pattern when an electron beam with a diameter of 300 nm is incident. From 7(B), a ring-shaped diffraction pattern is observed. Therefore, electron diffraction also shows It can be seen that the a-axis and b-axis of the pellets contained in CAAC-OS do not have orientation. Note that the first ring in Figure 47(B) is the (010) plane of the InGaZnO4 crystal. This is thought to be caused by the nominal (100) plane, etc. Also, the second ring in Figure 47(B) This is thought to be caused by (110) planes, etc.

[0413] Furthermore, CAAC-OS is an oxide semiconductor with a low defect level density. Possible defects include, for example, defects caused by impurities or oxygen deficiencies. Therefore, CA AC-OS can also be described as an oxide semiconductor with a low impurity concentration. Furthermore, CAAC-O S can also be described as an oxide semiconductor with few oxygen vacancies.

[0414] Impurities in oxide semiconductors can act as carrier traps or carrier sources. This can happen. Also, oxygen vacancies in oxide semiconductors can act as carrier traps, It can sometimes become a carrier source by capturing hydrogen.

[0415] Impurities are elements other than the main components of oxide semiconductors, such as hydrogen, carbon, silicon, and transition gold. There are group elements, for example. For example, silicon and other metal elements that make up oxide semiconductors are more acidic than the metal elements that make up oxide semiconductors. Elements with strong bonding forces can remove oxygen from oxide semiconductors, thereby altering the atomic arrangement of the oxide semiconductor. This disrupts the crystallinity and reduces its properties. Also, heavy metals such as iron and nickel, and argon, Because carbon dioxide and other elements have large atomic radii (or molecular radii), the atomic arrangement of oxide semiconductors This disrupts the crystallinity and reduces its properties.

[0416] Furthermore, oxide semiconductors with a low defect level density (few oxygen vacancies) have a low carrier density. Such oxide semiconductors can be made into high-purity intrinsic or substantially high-purity intrinsic materials. It is called an oxide semiconductor. CAAC-OS has a low impurity concentration and a low defect level density. Therefore, CA Transistors using AC-OS exhibit electrical characteristics where the threshold voltage is negative (normally It is also called -on.) It rarely becomes. Also, high purity intrinsic or substantially high purity intrinsic Oxide semiconductors have few carrier traps. The charged particles take a long time to release, behaving almost like fixed charges. Therefore, transistors using oxide semiconductors with high impurity concentrations and high defect level densities are available. Distors can sometimes have unstable electrical characteristics. On the other hand, transients using CAAC-OS This results in a transistor with minimal variation in electrical characteristics and high reliability.

[0417] Furthermore, because CAAC-OS has a low defect level density, it is less susceptible to damage from light irradiation and other factors. Carriers are rarely trapped in defect levels. Therefore, using CAAC-OS Lampistors exhibit minimal changes in their electrical properties due to irradiation with visible or ultraviolet light.

[0418] <Microcrystalline oxide semiconductor> Next, we will explain microcrystalline oxide semiconductors.

[0419] Microcrystalline oxide semiconductors have regions where crystalline parts can be observed in high-resolution TEM images. It has regions where a clear crystalline structure cannot be observed, and regions where a clear crystalline structure cannot be observed. The crystalline portion contained is between 1 nm and 100 nm in size, or between 1 nm and 10 nm in size. This is often the case. In particular, microcrystalline molecules between 1 nm and 10 nm, or between 1 nm and 3 nm. Oxide semiconductors having nanocrystals are called nc-OS (nanocrystallin It is called e Oxide Semiconductor. nc-OS is, for example, a high-resolution semiconductor. In some cases, grain boundaries cannot be clearly identified in TEM images. Note that nanocrystals are CAA It may have the same origin as the pellets in C-OS. Therefore, nc- The crystalline portion of an operating system (OS) is sometimes referred to as a pellet.

[0420] nc-OS is used in minute regions (for example, regions between 1 nm and 10 nm, especially regions larger than 1 nm). It has periodicity in the atomic arrangement in the region of 3 nm or less. In addition, nc-OS has different properties. No regularity is observed in the crystal orientation between the letts. Therefore, no orientation is observed throughout the entire film. Therefore, depending on the analytical method, nc-OS may be indistinguishable from amorphous oxide semiconductors. There are cases where XRD equipment using X-rays with a larger diameter than pellets is used for nc-OS. When structural analysis is performed using this method, the out-of-plane method reveals the crystal planes. No peaks are detected. Also, compared to nc-OS, the probe diameter is larger than that of the pellet. For example, electron diffraction (also called limited-field electron diffraction) is performed using an electron beam of 50 nm or greater. Then, a diffraction pattern resembling a halo pattern is observed. On the other hand, for nc-OS, Pelle Nanobeam electron diffractometers use electron beams with a probe diameter close to or smaller than the pellet size. When the beam is folded, a spot is observed. Furthermore, nanobeam electron diffraction is performed on the nc-OS. In some cases, a region of high brightness can be observed in a circular (ring-shaped) pattern. Furthermore, Multiple spots may be observed within a ring-shaped region.

[0421] Thus, since there is no regularity in the crystal orientation between pellets (nanocrystals), nc -OS has RANC (Random Aligned nanocrystals) Oxide semiconductors, or NANC (Non-Aligned nanocrystals), It can also be called an oxide semiconductor having s).

[0422] nc-OS is an oxide semiconductor with higher orderliness than amorphous oxide semiconductors. nc-OS has a lower defect level density than amorphous oxide semiconductors. However, nc-O S shows no regularity in crystal orientation between different pellets. Therefore, nc-OS is C Compared to AAC-OS, the defect level density is higher.

[0423] <Amorphous oxide semiconductor> Next, we will explain amorphous oxide semiconductors.

[0424] Amorphous oxide semiconductors are characterized by an irregular arrangement of atoms within the film and lack of crystalline regions. It is a material semiconductor. One example is an oxide semiconductor that has an amorphous state, such as quartz.

[0425] In amorphous oxide semiconductors, crystalline regions cannot be observed in high-resolution TEM images.

[0426] When structural analysis of amorphous oxide semiconductors is performed using an XRD device, out-of-p Analysis using the Lane method did not detect any peaks indicating crystal planes. Furthermore, amorphous oxide semi-crystalline materials were found. When electron diffraction is performed on a conductor, a halo pattern is observed. Furthermore, amorphous oxide semiconductors... When nanobeam electron diffraction is performed on a body, no spots are observed, only a halo pattern is seen. It is observed.

[0427] Various views have been expressed regarding amorphous structures. For example, some argue that there is absolutely no order in the arrangement of atoms. A structure that does not possess a completely amorphous structure It is sometimes called the nearest neighbor distance or second nearest neighbor distance. A structure that possesses order but lacks long-range order is sometimes called an amorphous structure. Therefore, according to the most strict definition, an oxide semiconductor having even a slight order in its atomic arrangement is non- It cannot be called a crystalline oxide semiconductor. Furthermore, it does not possess long-range order. A material semiconductor cannot be called an amorphous oxide semiconductor. Therefore, since it has a crystalline portion... For example, CAAC-OS and nc-OS are amorphous oxide semiconductors or completely amorphous It cannot be called an oxide semiconductor.

[0428] <Amorphous-like oxide semiconductor> Furthermore, oxide semiconductors may have a structure between nc-OS and amorphous oxide semiconductors. Yes, such an oxide semiconductor is a type of oxide semiconductor, particularly an amorphous-like oxide semiconductor (al). ike OS:amorphous-like Oxide Semiconducto It is called r).

[0429] a-like OS is characterized by the observation of porosity (also called voids) in high-resolution TEM images. In some cases, the crystalline portion can be clearly identified in high-resolution TEM images. It has a region and a region where the crystalline part cannot be identified.

[0430] Due to its porous nature, a-like OS has an unstable structure. Below, a-lik This demonstrates that e OS has a less stable structure compared to CAAC-OS and nc-OS. Therefore, it shows the structural changes caused by electron irradiation.

[0431] The samples to be irradiated with electrons are a-like OS (referred to as sample A) and nc-OS. Prepare (referred to as Sample B) and CAAC-OS (referred to as Sample C). This sample is also an In-Ga-Zn oxide.

[0432] First, high-resolution cross-sectional TEM images are obtained for each sample. It can be seen that all of the materials contain crystalline parts.

[0433] The determination of which part should be considered a single crystal can be made as follows. The unit cell of the InGaZnO4 crystal has three In-O layers and a Ga-Zn-O layer. It is known to have a structure in which a total of nine layers, consisting of six layers, are stacked in layers along the c-axis. The spacing between these adjacent layers is approximately the same as the spacing between the grid planes of the (009) plane (also called the d value). Therefore, the value has been determined to be 0.29 nm from crystal structure analysis. The areas where the spacing is between 0.28 nm and 0.30 nm are considered to be the crystalline parts of InGaZnO4. It can be considered as such. Furthermore, the lattice patterns correspond to the ab-plane of the InGaZnO4 crystal.

[0434] Figure 48 shows an example of investigating the average size of the crystalline regions (22 to 45 locations) in each sample. However, the length of the lattice fringes mentioned above is used as the size of the crystal portion. From Figure 48, a-li It can be seen that the crystalline portion of keOS increases in proportion to the cumulative amount of electron irradiation. Specifically, as shown in (1) in Figure 48, the initial TEM observation is approximately 1.2 nm. The crystal region (also called the initial nucleus), which was initially a certain size, increased in size when the cumulative irradiation dose reached 4.2 × 10⁻⁶. 8 e - / n m 2 In this case, it can be seen that it has grown to a size of about 2.6 nm. On the other hand, nc-O S and CAAC-OS have a cumulative electron dose of 4.2 × 10⁻⁶ from the start of electron irradiation. 8 e - / nm 2 Within this range, it can be seen that there is no change in the size of the crystal portion. Specifically, As shown in (2) and (3) in Figure 48, regardless of the cumulative dose of electrons, nc-OS The sizes of the crystal parts of yobi CAAC-OS are about 1.4 nm and about 2.1 nm, respectively. It can be seen that they are so.

[0435] Thus, crystal growth of a-like OS can be observed in some cases by electron irradiation. On the other hand, it can be seen that crystal growth of nc-OS and CAAC-OS due to electron irradiation is hardly observed. That is, it can be seen that a-like OS has a less stable structure compared with nc-OS and CAAC-OS. OS.

[0436] In addition, because it has looseness, a-like OS has a lower density structure compared with nc-OS and CAAC-OS. Specifically, the density of a-like OS is 78.6% or more and less than 92.3% of the density of a single crystal with the same composition. Further, the density of nc-OS and the density of CAAC-OS are 92.3% or more and less than 100% of the density of a single crystal with the same composition. An oxide semiconductor with a density less than 78% of the density of a single crystal is difficult to form a film itself.

[0437] For example, in an oxide semiconductor satisfying In:Ga:Zn = 1:1:1 [atomic ratio], the density of a single crystal InGaZnO4 having a rhombohedral crystal structure is 6.357 g / cm 3 3 3 3 3 ​​​​​​​​​​​​​It will be less than.

[0438] Note that single crystals with the same composition may not exist. In that case, a mixture of crystals with different compositions in any proportion may be used. By combining single crystals, the density equivalent to a single crystal at a desired composition can be estimated. This is possible. The density corresponding to a single crystal of the desired composition can be obtained by combining single crystals of different compositions. The proportion can be estimated using a weighted average. However, the density should be as small as possible. It is preferable to estimate by combining different types of single crystals.

[0439] As described above, oxide semiconductors can take on various structures, each possessing a variety of properties. Oxide semiconductors include, for example, amorphous oxide semiconductors, a-like OS, and microcrystalline oxide semiconductors. The film may be a multilayer film containing two or more materials, including a monocrystalline semiconductor and CAAC-OS.

[0440] <Film deposition model> The following describes an example of a film deposition model for CAAC-OS and nc-OS.

[0441] Figure 49(A) shows the process of depositing CAAC-OS by sputtering. This is a schematic diagram of the inside of a membrane chamber.

[0442] Target 5130 is bonded to the backing plate. Multiple magnets are positioned facing the target 5130 via the same means. A magnetic field is generated by the number of magnets. The magnetic field from the magnets is used to increase the film deposition rate. This sputtering method is called magnetron sputtering.

[0443] The substrate 5120 is positioned facing the target 5130, and the distance d( The distance between the target and substrate (also called the TS distance) is preferably 0.01m or more and 1m or less. Alternatively, the depth should be between 0.02m and 0.5m. The deposition chamber is mostly filled with deposition gas (for example, Filled with oxygen, argon, or a mixed gas containing oxygen at a ratio of 5% or more by volume, 0.0 The pressure is controlled to be between 1 Pa and 100 Pa, preferably between 0.1 Pa and 10 Pa. Then, by applying a voltage above a certain level to target 5130, discharge begins, and plasma This is confirmed. Furthermore, a high-density plasma region is formed near target 5130 by the magnetic field. Formed. In the high-density plasma region, the film-forming gas is ionized, resulting in ion 5101 This occurs. Ion 5101 is, for example, the cation of oxygen (O + ) and argon cations ( Ar + ) and so on.

[0444] Here, target 5130 has a polycrystalline structure having multiple crystal grains, and any Crystal grains contain cleavage planes. Figure 50(A) shows, as an example, the cleavage planes contained in target 5130. The crystal structure of InGaZnO4 is shown. Note that Figure 50(A) is in the direction parallel to the b-axis. The structure of the InGaZnO4 crystal is observed from Figure 50(A). In each Ga-Zn-O layer, the oxygen atoms in each layer are arranged in close proximity to each other. It can be seen that the oxygen atom has a negative charge, and two adjacent atoms A repulsive force is generated between the Ga-Zn-O layers. As a result, the InGaZnO4 crystals are adjacent to each other. The two Ga-Zn-O layers have a cleavage plane between them.

[0445] Ions 5101 generated in the high-density plasma region are directed toward the target 5130 by the electric field. It is accelerated and eventually collides with target 5130. At this time, from the cleavage plane, it becomes flat or pegged. The pellets 5100a and 5100b, which are red-shaped sputtered particles, detached. It is knocked out. Note that pellets 5100a and 5100b are ion 5101 The impact of the collision may cause structural distortion.

[0446] Pellet 5100a is a flat plate or pellet having a triangular, for example, equilateral triangle plane. These are sputtered particles in a specific shape. Furthermore, pellet 5100b has a hexagonal shape, for example, a regular hexagonal plane. These are flat or pellet-shaped sputtered particles having [a certain characteristic]. Note that pellet 5100a and The term "pellets" refers collectively to flat or pellet-shaped sputtered particles such as pellet 5100b. It is called 5100. The planar shape of the pellet 5100 is not limited to triangles or hexagons, for example. For example, it can take the form of a shape made up of multiple triangles joined together. In some cases, two polygons (or sides) can be joined together to form a quadrilateral (for example, a rhombus).

[0447] The thickness of pellet 5100 is determined by the type of film-forming gas used, etc. The reason will be explained later. The thickness of the pellet 5100 is preferably uniform. Also, the sputtered particles have a thickness It is preferable for it to be in the form of pellets rather than in the form of thick cubes. The 5100 has a thickness of 0.4 nm to 1 nm, preferably 0.6 nm to 0.8 nm. The width should be less than or equal to m. Also, for example, pellet 5100 should preferably have a width of 1 nm or more and 3 nm or less. The n is 1.2 nm to 2.5 nm. Pellet 5100 is (1 in Figure 48 above) This corresponds to the initial nucleus described in ). For example, target 5 having In-Ga-Zn oxide. When ion 5101 is collided with 130, the Ga-Zn-O layer is formed as shown in Figure 50(B). Then, the pellet 5100, which has three layers including an In-O layer and a Ga-Zn-O layer, peels off. Figure 5 Figure 0(C) shows the structure of the detached pellet 5100 as observed from a direction parallel to the c-axis. Let 5100 is a nano-sized saturation It can also be called an Indowich structure.

[0448] Pellet 5100 may become negatively or positively charged on its sides as it passes through the plasma. For example, in pellet 5100, oxygen atoms located on the sides may be negatively charged. The sides have charges of the same polarity, causing repulsion between the charges, resulting in a flat or plate-like shape. It becomes possible to maintain a lettuce-like shape. Furthermore, CAAC-OS is In-Ga-Z In the case of an indium oxide, the oxygen atom bonded to the indium atom may be negatively charged. Alternatively, an oxygen atom bonded to an indium atom, gallium atom, or zinc atom is negatively charged. There is a possibility that... Also, when pellet 5100 passes through the plasma, A field that grows by bonding with atoms such as gallium, zinc, and oxygen. There is a match. The difference in size between (2) and (1) in Figure 48 above is due to the growth in the plasma. This corresponds to the case where the substrate 5120 is at room temperature, and the pellets on the substrate 5120 Because growth of 5100 is unlikely, it becomes nc-OS (see Figure 49(B)). At room temperature Because it can be deposited in degrees, nc-OS can be deposited even when the substrate 5120 has a large area. In addition, to grow pellet 5100 in plasma, the sputtering method is used. Increasing the deposition power in this process is effective. By increasing the deposition power, pellet 5 It can stabilize 100 structures.

[0449] As shown in Figures 49(A) and 49(B), for example, pellet 5100 is plasma It flies through the air like a kite, fluttering upwards onto circuit board 5120. Pellet 5 Because pellet 100 is charged, it approaches an area where other pellets 5100 have already accumulated. This generates a repulsive force. Here, on the upper surface of the substrate 5120, the direction parallel to the upper surface of the substrate 5120 A magnetic field (also called a horizontal magnetic field) is generated. Also, substrate 5120 and target 5 A potential difference is applied between 130 and 130, so the current flows from the substrate 5120 to the target 5130. Current flows in that direction. Therefore, on the upper surface of the substrate 5120, A force (Lorentz force) is exerted by the action of a magnetic field and electric current. This is what Fleming described. This can be understood through the left-hand rule.

[0450] Pellet 5100 has a larger mass than a single atom. Therefore, on the substrate 5120 In order to move a surface, it is important to apply some kind of force from the outside. One of those forces is It is possible that this force is generated by the interaction of a magnetic field and electric current. To apply sufficient force to move the top surface of 5120, on the top surface of the substrate 5120, A magnetic field parallel to the upper surface of the substrate 5120 is 10G or more, preferably 20G or more, and more preferably It is preferable to provide a region where the bandwidth is 30G or more, more preferably 50G or more. Alternatively, On the upper surface of plate 5120, a magnetic field parallel to the upper surface of substrate 5120 is present on the substrate 5120. A magnetic field perpendicular to the upper surface that is 1.5 times or more, preferably 2 times or more, and more preferably 3 times or more. Furthermore, it is preferable to provide a region that is five times or more more than the above.

[0451] At this time, the magnet and the substrate 5120 move or rotate relative to each other. Therefore, the direction of the horizontal magnetic field on the upper surface of the substrate 5120 continues to change. On the upper surface of plate 5120, the pellet 5100 is subjected to forces from various directions, and in various directions You can move to [location].

[0452] Furthermore, as shown in Figure 49(A), when the substrate 5120 is heated, the pellet 510 The resistance between 0 and the substrate 5120 due to friction etc is low. As a result, The pellet 5100 moves as if gliding across the top surface of the substrate 5120. The movement occurs with the flat surface facing the substrate 5120. After that, other already deposited material... When it reaches the side of pellet 5100, the sides fuse together. At this point, pellet 51 The oxygen atom on the side of 00 is removed. The removed oxygen atom is released from the CAAC-OS Because oxygen vacancies may be filled, CAAC-OS has a low defect level density. The temperature of the top surface of plate 5120 is, for example, between 100°C and 500°C, or between 150°C and 450°C. It is sufficient to set it to less than 400°C, or between 170°C and 400°C. Therefore, the substrate 5120 has a large surface area. CAAC-OS can be deposited even in multiplicity formations.

[0453] Furthermore, when the pellet 5100 is heated on the substrate 5120, the atoms rearrange. The structural strain caused by the collision of ion 5101 is relieved. The strain-relieved pellet 5 100 is almost a single crystal. Pellet 5100 is almost a single crystal. Even if the pellets 5100 are heated after bonding together, the pellets 5100 themselves will not expand. Shrinkage is unlikely to occur. Therefore, the gaps between pellets 5100 widen, causing crystallization. It does not form defects such as grain boundaries, and does not create crevices.

[0454] Furthermore, CAAC-OS is not made of a single sheet of single-crystal oxide semiconductor. The aggregate of pellets 5100 (nanocrystals) resembles a stack of bricks or blocks. They are arranged in a specific pattern. Furthermore, there are no grain boundaries between the 5100 pellets themselves. Therefore, CAAC-OS can undergo deformation such as shrinkage due to heating during film formation, heating after film formation, or bending. Even in such cases, it is possible to relieve local stress or release strain. Therefore, This structure is suitable for use in flexible semiconductor devices. Note that nc-OS is a type of pe The arrangement resembles a chaotic stacking of Lett 5100 (nanocrystals).

[0455] When target 5130 was sputtered with ion 5101, not only pellet 5100 but also Furthermore, zinc oxide and other materials may peel off. Zinc oxide is lighter than pellet 5100. Therefore, it first reaches the top surface of substrate 5120. Then, 0.1nm to 10nm, 0. A zinc oxide layer 5102 with a thickness of 2 nm to 5 nm, or 0.5 nm to 2 nm, is formed. Figure 51 shows a schematic cross-sectional view.

[0456] As shown in Figure 51(A), pellets 5105a and pellets are placed on the zinc oxide layer 5102. Pellet 5105b and pellet 5105b are deposited. Here, pellet 5105a and pellet 5105b are, They are arranged so that their sides are touching each other. Also, pellet 5105c is pellet 510 After being deposited on 5b, it slides along on pellet 5105b. Also, pellet 51 In another aspect of 05a, multiple particles 510 were detached from the target along with zinc oxide. 3 crystallizes due to heating from the substrate 5120, forming region 5105a1. The number 5103 particles may contain oxygen, zinc, indium, and gallium, among others.

[0457] Then, as shown in Figure 51(B), region 5105a1 is integrated with pellet 5105a. It transforms into pellet 5105a2. Also, pellet 5105c has its sides that are pellets Position it so that it is in contact with another side of 5105b.

[0458] Next, as shown in Figure 51(C), pellet 5105d is further converted to pellet 5105a2 After being deposited on top of pellet 5105b, then on top of pellet 5105a2 and pellet 5 It moves smoothly along 105b. It also moves towards another side of pellet 5105c. The pellet 5105e then slides across the zinc oxide layer 5102.

[0459] Then, as shown in Figure 51(D), the pellet 5105d has a side surface that is the same as the pellet 51 It is positioned so as to be in contact with the side of 05a2. Also, pellet 5105e has its side facing the pellet Position it so that it is in contact with another side of pellet 5105c. Also, position it so that it is in contact with another side of pellet 5105d. On the surface, multiple particles 5103 that have been detached from target 5130 along with zinc oxide are the base The plate 5120 crystallizes upon heating, forming region 5105d1.

[0460] As described above, the stacked pellets are arranged so that they are in contact with each other, and on the sides of the pellets As crystal growth occurs, CAAC-OS is formed on the substrate 5120. Therefore, CAAC-OS pellets are larger than nc-OS pellets. (See Figure 48 above) The difference in size between (3) and (2) corresponds to the growth after deposition.

[0461] Furthermore, the gaps between pellets become extremely small, allowing one large pellet to be formed. In some cases, one large pellet has a single-crystal structure. For example, the large pellet The size, when viewed from the top surface, is between 10nm and 200nm, between 15nm and 100nm, and The wavelength can be between 20nm and 50nm. In this case, it is used in minute transistors. In oxide semiconductors, the channel formation region can sometimes be contained within a single large pellet. In other words, regions having a single-crystal structure can be used as channel-forming regions. As the lett size increases, the region with a single-crystal structure becomes the channel formation region of the transistor. It may be possible to use it as the source area and drain area.

[0462] Thus, the channel formation region of the transistor and other regions are formed in a region having a single-crystal structure. This can sometimes improve the frequency characteristics of a transistor.

[0463] Based on the above model, it is assumed that the pellets 5100 will be deposited on the substrate 5120. It is possible to form CAAC-OS films even when the surface to be formed does not have a crystalline structure. From certain factors, it can be seen that it is a different growth mechanism from epitaxial growth. Also, CA AC-OS does not require laser crystallization and can produce a uniform surface even on large-area glass substrates. A film can be formed. For example, the structure of the upper surface (the surface to be formed) of the substrate 5120 is an amorphous structure (for example It is possible to deposit CAAC-OS even on amorphous silicon oxide.

[0464] Furthermore, CAAC-OS can be used even if the upper surface of the substrate 5120, which is the surface to be formed on, has irregularities. It can be seen that the pellets 5100 are arranged according to that shape. For example, on the substrate 5120 If the surface is flat at the atomic level, the pellet 5100 has a flat surface that is parallel to the ab plane. Place them side by side facing downwards. If the thickness of the pellets 5100 is uniform, then the thickness is uniform and flat, A layer with high crystallinity is formed. Then, n layers (where n is a natural number) are stacked. By doing so, you can obtain CAAC-OS.

[0465] On the other hand, even if the upper surface of the substrate 5120 has irregularities, CAAC-OS can still use pellets 51 The structure consists of n layers (where n is a natural number) of 00s placed side by side along the contours. (Substrate 5) Because the 120 has an uneven surface, gaps tend to form between the 5100 pellets in CAAC-OS. There are cases where this occurs. However, even in this case, intermolecular forces act between the pellets 5100, and the unevenness persists. However, the pellets are arranged so that the gaps between them are as small as possible. Therefore, even if there are bumps and uneven surfaces This can also result in a CAAC-OS with high crystallinity.

[0466] Because CAAC-OS is deposited using this model, the sputtered particles have a thickness It is preferable that the sputtered particles are in the form of pellets. In addition, if the surface facing the substrate 5120 is not constant, and the thickness and crystal orientation cannot be made uniform, There is.

[0467] Based on the film formation model described above, high crystallinity can be achieved even on a film-forming surface having an amorphous structure. A CAAC-OS with the properties can be obtained.

[0468] <cleavage plane> The following describes the cleavage plane of the target described in the CAAC-OS film deposition model. I will reveal it.

[0469] First, we will explain the cleavage plane of the target using Figure 52. Figure 52 shows InGaZ The crystal structure of nO4 is shown. Note that in Figure 52(A), the c-axis is oriented upwards, and the b-axis is parallel to it. The structure of the InGaZnO4 crystal when observed from the direction is shown. Also, Figure 52(B) shows c The structure of the InGaZnO4 crystal observed from a direction parallel to the axis is shown.

[0470] The energy required for cleavage at each crystal plane of an InGaZnO4 crystal is calculated using first-principles calculations. It is calculated using the following method. Note that the calculation involves pseudopotentials and density functionals using plane wave basis vectors. The program (CASTEP) is used. Note that the pseudopotential is an ultrasoft type pseudopotential. Potentials are used. The GGA PBE functional is used. Also, cutoff The energy is assumed to be 400 eV.

[0471] The energy of the structure in its initial state is derived after structural optimization, including cell size. To release. Also, the energy of the structure after cleavage on each plane is, with the cell size fixed, the energy of the atom This is derived after optimizing the arrangement structure.

[0472] Based on the crystal structure of InGaZnO4 shown in Figure 52, the first face, second face, and third face A structure is created by cleaving along either the first or fourth face, and a structural optimization calculation is performed with a fixed cell size. This is done. Here, the first plane is the crystal plane between the Ga-Zn-O layer and the In-O layer, ( The second plane is a crystal plane parallel to the 001) plane (or ab plane) (see Figure 52(A)). , a crystal plane between the Ga-Zn-O layers, which is a crystal plane parallel to the (001) plane (or the a b plane) (see Fig. 52(A)). The third plane is a crystal plane parallel to the (110) plane (see Fig. 52(B)). The fourth plane is a crystal plane parallel to the (100) plane (or the bc plane (see Fig. 52(B)).

[0473] Under the above conditions, the energy of the structure after cleavage on each plane is calculated. Next, the difference between the energy of the structure after cleavage and the energy of the structure in the initial state is divided by the area of the cleavage plane to calculate the cleavage energy, which is a measure of the ease of cleavage on each plane. Note that the energy of the structure is the energy considering the kinetic energy of electrons and the interactions between atoms, between atom-electrons, and between electrons included in the structure .

[0474] As a result of the calculation, the cleavage energy of the first plane is 2.60 J / m 2 , the cleavage energy of the second plane is 0.68 J / m 2 , the cleavage energy of the third plane is 2.18 J / m 2 , and the cleavage energy of the fourth plane is 2.12 J / m 2 (see the following table).

[0475]

Table 1

[0476] From this calculation, in the crystal structure of InGaZnO4 shown in Fig. 52, the cleavage energy on the second plane is the lowest. That is, it can be seen that this is the plane (cleavage plane) where the Ga-Zn-O layers are most easily cleaved. Therefore, in this specification ​When referring to a cleavage plane, it means the second plane, which is the easiest plane to cleave.

[0477] Because there is a cleavage plane on the second surface between the Ga-Zn-O layers, Figure The InGaZnO4 crystal shown in 52(A) is separated by two planes equivalent to the second plane. This is possible. Therefore, when colliding ions with a target, the most cleavage energy is achieved. Wafer-like units (which we call pellets) cleaved from the lower surface of the ghee are the most... It is thought that they will be ejected in small units. In that case, the InGaZnO4 pellets The structure consists of three layers: a Ga-Zn-O layer, an In-O layer, and another Ga-Zn-O layer.

[0478] Furthermore, the first plane (the crystal plane between the Ga-Zn-O layer and the In-O layer, the (001) plane) (or crystal planes parallel to the ab plane) are more favorable than the third plane (crystal plane parallel to the (110) plane), The cleavage energy of the fourth face (a crystal plane parallel to the (100) plane (or bc plane)) is low. This suggests that the planar shape of pellets is often triangular or hexagonal.

[0479] Next, classical molecular dynamics calculations were performed to determine that InGa, which has a homologous structure, is the target. Assuming a ZnO4 crystal, the target is subjected to argon (Ar) or oxygen (O). We evaluate the cleavage plane when puttered. The InGaZnO4 crystal used in the calculation (26 The cross-sectional structure of the 88-atom atom is shown in Figure 53(A), and the top surface structure is shown in Figure 53(B). The fixed layer shown in (A) is a layer in which the arrangement of atoms is fixed so that their positions do not change. The temperature-controlled layer shown in 53(A) is a layer that is always kept at a constant temperature (300K).

[0480] For classical molecular dynamics calculations, we use Fujitsu Limited's Materials Explorer 5. Use 0.0. Note that the initial temperature is 300K, the cell size is constant, and the time step size is 0.01f. Assume a time of 10 million steps per minute. In the calculation, under these conditions, 300 atoms By applying an energy of eV, atoms are introduced into the cell from a direction perpendicular to the ab-plane of the InGaZnO4 crystal. Inject it.

[0481] Figure 54(A) shows argon being introduced into a cell containing the InGaZnO4 crystal shown in Figure 53. The atomic arrangement 99.9 picoseconds (psec) after irradiation is shown. Also, Figure 54(B) shows the arrangement. This shows the atomic arrangement 99.9 picoseconds after oxygen is incident on the atom. Note that Figure 54 is the same as Figure 53. A portion of the fixed layer shown in (A) is omitted.

[0482] From Figure 54(A), within 99.9 picoseconds after argon enters the cell, as shown in Figure 52(A) Cracks arise from the cleavage plane corresponding to the second plane shown in ). Therefore, InGaZnO4 When argon strikes the crystal, if the top surface is considered the second surface (0th), then the second surface ( Secondly, a large crack can be seen.

[0483] On the other hand, from Figure 54(B), within 99.9 picoseconds after oxygen enters the cell, Figure 52( It can be seen that a crack originates from the cleavage plane corresponding to the second plane shown in A). However, oxygen In the event of a collision, a large crack will form on the second (first) face of the InGaZnO4 crystal. You will understand.

[0484] Therefore, the upper surface of the target containing the InGaZnO4 crystal having a homologous structure When an atom (ion) collides with it, the InGaZnO4 crystal cleaves along the second plane. It can be seen that the flat particles (pellets) are detached. Also, at this time, the size of the pellets It has been found that the value is smaller when colliding with oxygen than when colliding with argon. Light.

[0485] Furthermore, the above calculations suggest that the detached pellets contain damaged areas. The damaged areas contained within the torn can be repaired by reacting oxygen with the defects caused by the damage. There are cases where this is the case.

[0486] Therefore, we investigated whether the size of the pellets differs depending on the type of atoms colliding with them. do.

[0487] Figure 55(A) shows argon being introduced into a cell containing the InGaZnO4 crystal shown in Figure 53. The trajectory of each atom from 0 picoseconds to 0.3 picoseconds after irradiation is shown. Therefore, Figure 55(A) corresponds to the period between Figure 53 and Figure 54(A).

[0488] As shown in Figure 55(A), argon 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 reaches the vicinity of the 6th layer (Ga-Zn-O layer). The argon that collides is ejected outwards. Therefore, the crystals containing InGaZnO4 are... When argon is fired at the target, the second surface (second) in Figure 53(A) shows a turtle It is likely that a crack will form.

[0489] Furthermore, Figure 55(B) shows that oxygen is present in the cell containing the InGaZnO4 crystal shown in Figure 53. This shows the trajectory of each atom from 0 picoseconds to 0.3 picoseconds after incidence. Therefore, Figure 55(B) corresponds to the period between Figure 53 and Figure 54(A).

[0490] On the other hand, as shown in Figure 55(B), oxygen clashes with gallium (Ga) in the first layer (Ga-Zn-O layer). Upon impact, the gallium then collides with the zinc (Zn) in the third layer (Ga-Zn-O layer), It can be seen that the zinc does not reach the fifth layer (In-O layer). Oxygen is ejected to the outside. Therefore, in the target containing the InGaZnO4 crystal... When oxygen is impacted, it is thought that a crack will form on the second surface (first) in Figure 53(A). It can be done.

[0491] This calculation also shows that when atoms (ions) collide in an InGaZnO4 crystal, the cleavage plane... This suggests that it may peel off.

[0492] Furthermore, we will examine the differences in crack depth from the perspective of conservation laws. Energy conservation law and momentum The conservation laws can be expressed as shown in equations (1) and (2). Here, E is the amount of air before the collision. The energy of argone or oxygen (300 eV), m A is the mass of argon or oxygen, v A v' is the velocity of argon or oxygen before the collision. A This is the rate of argon or oxygen after the collision. , m Ga v is the mass of gallium. Ga v' is the velocity of gallium before the collision. Ga The crash after the collision It is the speed of Um.

[0493]

number

[0494]

number

[0495] Assuming that the collision of argon or oxygen is an elastic collision, v A , v' A , v Ga Oh bi v' Ga The relationship can be expressed as shown in equation (3).

[0496]

number

[0497] From equations (1), (2), and (3), v Ga If we set to 0, then argon or oxygen Gallium's velocity v' after the collision Ga This can be expressed as shown in equation (4).

[0498]

number

[0499] In equation (4), m A Substitute the mass of argon or oxygen into the given values ​​for each atom. Compare the gallium velocities after the collision. The energy of argon and oxygen before the collision. If the values ​​are the same, the impact of argon is 1.2 times greater than that of oxygen. It can be seen that gallium has a speed four times higher. Therefore, the energy that gallium possesses is also higher. The velocity of the collision with Gon is squared compared to the velocity of the collision with oxygen.

[0500] When argon is used in a collision, the amount of gallium after the collision is greater than when oxygen is used in a collision. It can be seen that the velocity (energy) will increase. Therefore, when argon is collided, This suggests that the crack formed at a deeper location than when oxygen was impacted.

[0501] Based on the above calculations, a target containing an InGaZnO4 crystal having a homologous structure is obtained. When sputtered, it can be seen that it peels off from the cleavage plane and forms pellets. On the other hand, cleavage Sputtering other structural areas of a target that do not have a surface does not form pellets. Sputtered particles, which are even finer than a treadle and at the atomic level, are formed. These sputtered particles are Because they are smaller than pellets, they are transmitted via the vacuum pump connected to the sputtering apparatus. It is thought to be exhausted. Therefore, the InGaZnO4 crystal has a homologous structure. When a target containing particles is sputtered, particles of various sizes and shapes fly to the substrate and pile up. A model in which the film is formed by accumulation is unlikely. Sputtered pellets accumulate and CAA The model described in Figure 49(A) for depositing C-OS is reasonable.

[0502] The density of the CAAC-OS film formed in this manner is comparable to that of single-crystal OS. For example, the density of a single crystal OS having 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 / c³. m 3 It will be to that extent.

[0503] Figure 56 shows the CAAC-OS, an In-Ga-Zn oxide film deposited by sputtering. (See Figure 56(A)), and the cross-section of its target (See Figure 56(B)). The atomic arrangement is shown. For observing the atomic arrangement, high-angle scattering annular dark-field scanning transmission electron microscopy (HA) is used. ADF-STEM:High-Angle Annular Dark Field S canning Transmission Electron Microscopy ) is used. Note that in HAADF-STEM, the image intensity of each atom is proportional to the square of its atomic number. Therefore, Zn (atomic number 30) and Ga (atomic number 31), which have similar atomic numbers, They are almost indistinguishable. HAADF-STEM includes the Hitachi Scanning Transmission Electron Microscope HD-27. Use 00.

[0504] Comparing Figure 56(A) and Figure 56(B), CAAC-OS and the target are, Both exhibit homologous structures, indicating that the arrangement of each atom corresponds to a specific structure. Therefore, as shown in the film deposition models such as Figure 49(A), the target crystal structure is transformed. The image shows that CAAC-OS is being deposited.

[0505] <Regarding oxide semiconductor films and metal oxide films> Oxide semiconductors, such as the oxide semiconductor film 308b shown in Figure 1, used in transistors. A film formed by (hereinafter referred to as an oxide semiconductor film (OS)) and used as an electrode for a capacitive element A film formed from an oxide conductor, such as the metal oxide film 308c shown in Figure 1 (hereinafter) These are called oxide conductive films (OC). Regarding the temperature dependence of resistivity in each of these, Let's explain using Figure 57. In Figure 57, the horizontal axis shows the measured temperature, and the vertical axis shows the resistivity. Furthermore, the measurement results for oxide semiconductor films (OS) are indicated by circles, and the measurement results for oxide conductive films (OC) are shown. The result is indicated by a square mark.

[0506] Furthermore, for samples containing oxide semiconductor films (OS), the atomic ratio is In:Ga on a glass substrate. Thickness A 35nm In-Ga-Zn oxide film is formed, with an atomic ratio of In:Ga:Zn = 1:4 A 20nm thick In- A Ga-Zn oxide film is formed, then heat-treated in a nitrogen atmosphere at 450°C, followed by a nitrogen atmosphere at 450°C. The silicon oxide nitride film is then heated in an oxygen mixed gas atmosphere and further processed by plasma CVD. It was formed and manufactured.

[0507] Furthermore, samples containing oxide conductive films (OCs) are prepared on a glass substrate with an atomic ratio of In:Ga A sputtering method using a sputtering target with Zn=1:1:1 is used to create a thickness of 1 After forming a 00nm In-Ga-Zn oxide film and heat-treating it in a nitrogen atmosphere at 450°C The material is then heated in a mixed gas atmosphere of nitrogen and oxygen at 450°C and subjected to silica nitride by plasma CVD. It was fabricated by forming a film.

[0508] As can be seen from Figure 57, the temperature dependence of resistivity in an oxide conductive film (OC) is acid The temperature dependence of resistivity is smaller than that of oxide semiconductor films (OS). Typically, above 80K. The rate of change in resistivity of oxide conductive films (OC) below 290K is less than ±20%. Alternatively, the rate of change in resistivity between 150K and 250K is less than ±10%. In other words, oxide conductors are degenerate semiconductors in which the conduction band edge and the Fermi level coincide or are approximately the same. It is presumed that this is the case. For this reason, oxide conductive films are used in resistive elements, wiring, and capacitive elements. It can be used for electrodes, pixel electrodes, common electrodes, etc.

[0509] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0510] (Embodiment 11) As described in Embodiment 2, the transistor using an oxide semiconductor film is in the off state. The current value (off-current value) can be controlled to be low. Therefore, electrical signals such as image signals The retention time can be extended, and the write interval can also be set to a longer duration.

[0511] The liquid crystal display device of this embodiment uses transistors with low off-current values, At the very least, it can be a liquid crystal display device that displays using two driving methods (modes). The driving mode is the same as that of conventional liquid crystal display devices, which sequentially drives data frame by frame. This is a rewrite drive method. The second drive mode is performed after the data writing process is completed. This is a drive method that stops data rewriting. In other words, it reduces the refresh rate. This is the drive mode.

[0512] Videos are displayed using the first drive mode. Still images are displayed frame by frame. Since the image data does not change, there is no need to rewrite the data for each frame. When displaying still images, operating in the second drive mode eliminates screen flickering. In addition, it can reduce electricity consumption.

[0513] Furthermore, the liquid crystal elements used in the liquid crystal display device of this embodiment are large-area capacitive elements. It has the characteristic of accumulating a large capacitance value in the capacitive element. Therefore, the time for holding the potential of the pixel electrode is It can be extended, and a drive mode that reduces the refresh rate can be applied. Furthermore, when a drive mode that reduces the refresh rate is applied to a liquid crystal display device, Even if present, it is possible to suppress changes in the voltage applied to the liquid crystal layer for a long period of time, therefore it can be used. This can further prevent users from perceiving image flicker. Therefore, it reduces power consumption. This allows for an improvement in display quality.

[0514] Here, we will explain the effects of reducing the refresh rate.

[0515] There are two types of eye strain: nervous system fatigue and muscular system fatigue. Nervous system fatigue occurs over long periods of time. By continuously looking at the light-emitting and flashing screen of a liquid crystal display, the brightness can affect the retina, nerves, and brain. It stimulates and fatigues. Muscle fatigue affects the ciliary muscle, which is used when adjusting focus. It is a method of fatigue caused by overusing the muscles.

[0516] Figure 58(A) shows a schematic diagram representing the display of a conventional liquid crystal display device. As such, in conventional liquid crystal display devices, the image is rewritten 60 times per second. Prolonged exposure to such screens stimulates the user's retina, nerves, and brain. This could potentially cause eye strain.

[0517] In one aspect of the present invention, the pixel portion of a liquid crystal display device is provided with a transistor having an extremely low off-current, For example, a transistor using an oxide semiconductor is applied. Also, liquid crystal elements have a large area. It has capacitive elements. These suppress the leakage of charge accumulated in the capacitive elements. This makes it possible to maintain the brightness of the liquid crystal display even when the frame rate is reduced. .

[0518] In other words, as shown in Figure 58(B), for example, it is possible to rewrite the image once every 5 seconds. Therefore, it becomes possible to see the same image as much as possible, and the screen flickering that is visible to the user is reduced. This reduces the stimulation to the user's retina, nerves, and brain, thus reducing nervous system fatigue. This is reduced.

[0519] According to one aspect of the present invention, a liquid crystal display device that is easy on the eyes can be provided.

[0520] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

[0521] (Embodiment 12) This embodiment describes an example of the configuration of an electronic device to which a display device according to one aspect of the present invention is applied. Let me explain. In this embodiment, a display module to which a display device according to one aspect of the present invention is applied. Regarding "ru," we will explain it using Figure 59.

[0522] The display module 8000 shown in Figure 59 consists of an upper cover 8001 and a lower cover 8002. In between, the touch panel 8004 connected to the FPC8003 and the FPC8005 are connected. Display panel 8006, backlight unit 8007, frame 8009, printed circuit board It has a board 8010 and a battery 8011. It also has a backlight unit 8007 and a battery. Features such as the Terry 8011 and Touch Panel 8004 may not be available.

[0523] A display device according to one aspect of the present invention can be used, for example, as a display panel 8006.

[0524] The upper cover 8001 and the lower cover 8002 are the touch panel 8004 and the display panel. The shape and dimensions can be appropriately modified to match the size of the 8006.

[0525] The touch panel 8004 is a display panel using either a resistive or capacitive touch panel. It can be used superimposed on 8006. Also, the opposing substrate (sealing substrate) of the display panel 8006 It is also possible to incorporate touch panel functionality into the board. Alternatively, a display panel It is also possible to incorporate an optical sensor within each of the 8006 pixels to create an optical touch panel. Alternatively, an electrode for a touch sensor can be provided within each pixel of the display panel 8006, and a capacitive touch sensor can be used. It can also be used as a touch panel.

[0526] The backlight unit 8007 has a light source 8008. A configuration using a light-diffusing plate may be provided at the end of the unit 8007.

[0527] Frame 8009 provides protection for the display panel 8006, as well as the movement of the printed circuit board 8010. It has the function of an electromagnetic shield to block electromagnetic waves generated by the operation. The 8009 may also function as a heat sink.

[0528] The printed circuit board 8010 contains power supply circuits and signals for outputting video and clock signals. It has a power processing circuit. The power supply that provides power to the power supply circuit is an external commercial power supply. Alternatively, a separate power source, battery 8011, may also be used. Item 1 can be omitted when using commercial power.

[0529] Furthermore, the display module 8000 includes components such as polarizing plates, phase difference plates, and prism sheets. You may add more.

[0530] Figure 60 is an external view of an electronic device including a display device according to one embodiment of the present invention.

[0531] Examples of electronic devices include television equipment (televisions, or television receivers) (Also known as) Monitors for computers, digital cameras, digital video cameras, etc. Camera, digital photo frame, mobile phone (also called mobile phone or mobile phone device), mobile Examples include small game consoles, portable information terminals, sound playback devices, and large game machines such as pachinko machines. It can be done.

[0532] Figure 60(A) shows a portable information terminal, consisting of a main unit 1001, a housing 1002, and a display unit 10 It consists of 03a, 1003b, etc. The display unit 1003b is a touch panel. The screen is accessible by touching the keyboard buttons 1004 displayed on the display unit 1003b. It can be operated and text can be entered. Of course, the display unit 1003a can be configured as a touch panel. It may be done. The transistor shown in the above embodiment can be used as a switching element for a liquid crystal panel. By fabricating a light or organic light-emitting panel and applying it to the display units 1003a and 1003b, It can be used as a highly reliable portable information terminal.

[0533] The portable information terminal shown in Figure 60(A) can display various types of information (still images, videos, text images, etc.). Functions to display (date, time, etc.), a calendar, a function to display the date or time on the display unit, Functions to manipulate or edit displayed information, and processing by various software (programs). It can have functions to control, etc. Furthermore, external connection terminals can be located on the back or sides of the housing. The system may also include features such as an earphone jack, a USB port, and a recording medium insertion slot.

[0534] Furthermore, the portable information terminal shown in Figure 60(A) is configured to send and receive information wirelessly. This is also good. You can purchase desired book data, etc., from an e-book server wirelessly and download it. It is also possible to configure it as follows.

[0535] Figure 60(B) shows a portable music player, the main unit 1021 having a display unit 1023 and earpieces. A fixing part 1022 for mounting, a speaker, an operation button 1024, and an external memory slot. A 1025 and the like are provided. The transistor shown in the above embodiment is switched By fabricating liquid crystal panels and organic light-emitting panels as elements and applying them to the display unit 1023 This makes it a more reliable portable music player.

[0536] Furthermore, the portable music player shown in Figure 60(B) includes an antenna, microphone, and wireless functions. By having the user hold it and connecting it to their mobile phone, they can wirelessly control their hands while driving a car or other vehicle. Conversations in Lee are also possible.

[0537] Figure 60(C) shows a mobile phone, which consists of two housings, housing 1030 and housing 1031. The enclosure 1031 contains a display panel 1032, a speaker 1033, and a microphone. Phone 1034, pointing device 1036, camera 1037, external connection terminal 103 It is equipped with 8, etc. Also, the housing 1030 has a solar cell 1040 for charging mobile phones. It also features an external memory slot 1041, etc. The antenna is located inside the housing 1031. It is built-in. The transistor described in the above embodiment is applied to the display panel 1032. This makes it possible to create a highly reliable mobile phone.

[0538] Furthermore, the display panel 1032 is equipped with a touch panel, and Figure 60(C) shows an image display. Multiple operation keys 1035 are shown with dotted lines. Note that the output from the solar cell 1040 is A boost circuit is also implemented to increase the voltage from the source voltage to the voltage required for each circuit.

[0539] The display panel 1032 changes its orientation as appropriate depending on the usage mode. Since the camera 1037 is mounted on the same plane as the 1032, video calls are possible. Speaker 1033 and microphone 1034 are not limited to voice calls, but also video calls, recording, etc. Playback and other functions are possible. Furthermore, the housing 1030 and housing 1031 slide apart, as shown in Figure 60. As shown in C), it can be transformed from an unfolded state to an overlapping state, making it suitable for carrying around. It can be standardized.

[0540] External connection terminal 1038 can be connected to various cables such as AC adapters and USB cables. It is capable of charging and data communication with personal computers, etc. By inserting a recording medium into the memory slot 1041, it is possible to store and move larger amounts of data. Cut.

[0541] Furthermore, in addition to the above functions, it is equipped with infrared communication functions, television reception functions, etc. That's good too.

[0542] Figure 60(D) shows an example of a television system. The television system 1050 is The display unit 1053 is incorporated into the housing 1051. The display unit 1053 displays images. It is possible to show that the CPU is located inside the stand 1055 that supports the chassis 1051. It is housed there. The transistors described in the above embodiment are suitable for the display unit 1053 and the CPU. By using this, a highly reliable television device 1050 can be made.

[0543] The television device 1050 is operated using the control switches on the housing 1051, or a separate control unit. This can be done using a motor controller. Furthermore, the remote control unit can be configured to control the remote control operation. The system may also be configured to include a display unit that shows the information output from the machine.

[0544] The television system 1050 will be configured to include a receiver, modem, and other components. This allows for the reception of regular television broadcasts, and furthermore, wired or wireless connections are available via the modem. By connecting to a communication network, one-way (sender to receiver) or two-way communication is possible. It is also possible to perform two-way information communication (between a sender and receiver, or between receivers, etc.). .

[0545] Furthermore, the television device 1050 also has an external connection terminal 1054 and a storage medium playback and recording unit 1 052, It has an external memory slot. External connection terminal 1054 is a USB cable. It can be connected to various types of cables and enables data communication with personal computers and other devices. In the storage medium playback recording unit 1052, a disc-shaped recording medium is inserted, and the recording medium It is possible to read stored data and write to the storage medium. Also, external memory Images, videos, etc., stored in the external memory 1056 inserted into the reslot. It is also possible to display the information on the display unit 1053.

[0546] Furthermore, if the off-leak current of the transistor described in the above embodiment is extremely small, By applying this transistor to the external memory 1056 and CPU, the power consumption is reduced. This allows for a highly reliable television device 1050 with reduced processing time.

[0547] Note that the configurations and methods shown in this embodiment may differ from those shown in other embodiments. It can be used in appropriate combinations.

Claims

[Claim 1] Transistors on the circuit board, The inorganic insulating film in contact with the transistor, The organic insulating film in contact with the inorganic insulating film, A capacitive element electrically connected to the transistor, It has a pixel electrode formed on the organic insulating film and electrically connected to the transistor, The transistor has a gate electrode on the substrate, The oxide semiconductor film overlapping the gate electrode, A gate insulating film in contact with one surface of the oxide semiconductor film, The oxide semiconductor film has a pair of conductive films in contact with it, The capacitive element comprises a metal oxide film on the gate insulating film, The inorganic insulating film, The inorganic insulating film comprises a first light-transmitting conductive film, The display device is characterized in that the pixel electrode is formed of a second light-transmitting conductive film and is in contact with one of the pair of conductive films and the first light-transmitting conductive film.

Images