Display

Abstract

To provide a display having a capacitative element that is excellent in power consumption even when the number of sub-pixels constituting a pixel is increased.SOLUTION: The area of an opening in a sub-pixel controlling transmission of white light is made smaller than the area of an opening in the sub-pixel controlling transmission of red, green, and blue light. A transistor included in each of the sub-pixels has an oxide semiconductor film; a capacitative element has a first electrode and a second electrode; the first electrode is a metal oxide film in contact with an inorganic insulating film provided on the transistor; the second electrode is a conductive film having light transmissivity that is provided on the inorganic insulating film and electrically connected to the transistor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device.

[0002] The present invention is not limited to the above-mentioned technical fields. The present invention relates to a process, a machine, or a manufacturing method. relating to the manufacture or composition of matter Therefore, the technical field of one embodiment of the present invention disclosed in this specification is , a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, a driving method thereof, or The manufacturing method thereof can be cited as an example. [Background technology]

[0003] Color display devices use three primary colors, namely RGB (red, green, and blue) color filters. In practical use, pixels are configured with sub-pixels each having a backlight. The brightness of the light emitted from the screen is adjusted, and the color is displayed by additive RGB color mixing. This has been achieved.

[0004] In recent years, pixels have been configured with sub-pixels that transmit white light in addition to RGB, resulting in low power consumption and Alternatively, a display device that aims to improve brightness has been proposed (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-295717 Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration of Patent Document 1, a sub-pixel that transmits white light is provided, and the sub-pixels that make up one pixel As the number of pixels increases, the amount of wiring required to control each sub-pixel increases. The area occupied by the wiring increases. This makes it necessary to design the sub-pixels smaller. Considering that the size of the transistor and storage capacitor does not change, the area through which light passes can be reduced. Therefore, the brightness of the light transmitted by the backlight, etc. This creates a need to increase the power consumption, which leads to a problem of increased power consumption.

[0007] In view of this, one embodiment of the present invention provides a display device or the like having a novel structure that can reduce power consumption. Another object of one embodiment of the present invention is to reduce the number of wirings for controlling each subpixel. Another object of the present invention is to provide a display device or the like having a novel configuration that can reduce the number of One embodiment of the present invention is a display device having a novel configuration that can reduce the area occupied by the storage capacitor in the subpixel. Another object of the present invention is to provide a novel display device with excellent display quality. Another object of the present invention is to provide a display device or the like having a novel structure. One of the objects is to provide a new display device, etc.

[0008] The problems to be solved by the present invention are not limited to the problems listed above. This does not preclude the existence of other issues, which will be discussed in the following sections. Problems not mentioned in this section are problems that a person skilled in the art would be able to easily understand by looking at the specification or drawings, etc. These can be derived from the descriptions and can be extracted appropriately from these descriptions. One aspect of the invention is to achieve at least one of the above-listed and / or other objectives. This solves the problem. [Means for solving the problem]

[0009] One embodiment of the present invention is a display device including a pixel having first to fourth subpixels, The first to third sub-pixels are sub-pixels that control the transmission of any one of red, green, and blue light. The fourth subpixel is a subpixel that controls the transmission of white light, and the aperture of the fourth subpixel The area of the display device is smaller than the area of the openings of the first to third subpixels.

[0010] Another embodiment of the present invention is a display device including a pixel having first to fourth subpixels. Each of the first to fourth subpixels has a transistor and a capacitor. The capacitor has an oxide semiconductor film, and the capacitor has a first electrode and a second electrode. The electrode is a metal oxide film that contacts the inorganic insulating film provided on the transistor, and the second electrode a light-transmitting insulating film provided over an inorganic insulating film and electrically connected to a transistor; The first to third subpixels are conductive films, and the first to third subpixels control the transmission of any one of red, green, and blue light. The fourth subpixel is a subpixel that controls the transmission of white light, and the fourth subpixel is a subpixel that controls the transmission of white light. The area of the opening of the pixel is smaller than the areas of the openings of the first to third subpixels. do.

[0011] Another embodiment of the present invention is a display device including a pixel having first to fourth subpixels. Each of the first to fourth subpixels has a transistor and a capacitor. The capacitor has an oxide semiconductor film, and the capacitor has a first electrode and a second electrode. The electrode is a metal oxide film that contacts the inorganic insulating film provided on the transistor, and the second electrode a light-transmitting insulating film provided over an inorganic insulating film and electrically connected to a transistor; The first to fourth sub-pixels are arranged in two rows and two columns in the pixel. The first to third subpixels control the transmission of any one of red, green, and blue light. The fourth subpixel is a subpixel that controls the transmission of white light. The area of the opening of the second subpixel is smaller than the areas of the openings of the second to fourth subpixels.

[0012] Another embodiment of the present invention is a display device including a pixel having first to fourth subpixels. Each of the first to fourth subpixels has a transistor and a capacitor. The capacitor has an oxide semiconductor film, and the capacitor has a first electrode and a second electrode. The electrode is a metal oxide film that contacts the inorganic insulating film provided on the transistor, and the second electrode a light-transmitting insulating film provided over an inorganic insulating film and electrically connected to a transistor; The first to fourth sub-pixels are arranged in two rows and two columns in the pixel. a first wiring for supplying a first data signal to the first sub-pixel and the second sub-pixel; a second wiring for applying a second data signal to the third and fourth subpixels; and a signal for controlling writing of the first data signal or the second data signal to the third subpixel. a third wiring for supplying a first data signal or a second data signal to the second subpixel and the fourth subpixel; a fourth wiring for supplying a signal for controlling writing of the data signal; and a fifth wiring for applying a constant potential to the electrode. The first to third sub-pixels are red, green, and The fourth sub-pixel controls the transmission of either blue or white light. The fourth subpixel is a subpixel that controls transmission. The area of the aperture of the fourth subpixel is The display device is smaller than the area of the opening. [Effects of the Invention]

[0013] According to one embodiment of the present invention, a display device or the like having a novel structure capable of reducing power consumption is provided. Alternatively, according to one embodiment of the present invention, the number of wirings for controlling each subpixel can be reduced. According to one embodiment of the present invention, a display device or the like having a novel structure can be provided. and a display device having a novel configuration that can reduce the area occupied by a storage capacitor in a subpixel. Alternatively, according to one embodiment of the present invention, a display device with a novel structure and excellent display quality can be provided. Alternatively, one embodiment of the present invention can provide a novel display device or the like. It is possible.

[0014] The effects of the present invention are not limited to the effects listed above. This does not preclude the existence of other effects, as described below. Effects not mentioned in this section are effects that a person skilled in the art would understand by looking at the specification or drawings, etc. These can be derived from the descriptions and can be extracted appropriately from these descriptions. One aspect of the invention is to achieve at least one of the above-listed effects and / or other effects. Therefore, one aspect of the present invention may have the above-listed effects in some cases. In some cases, this is not the case. [Brief explanation of the drawings]

[0015] [Figure 1]FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Figure 3] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Figure 4] 1A and 1B are a block diagram and a circuit diagram illustrating one embodiment of the present invention. [Figure 5] 1A and 1B are a top view and a circuit diagram illustrating one embodiment of the present invention. [Figure 6] FIG. 1 is a top view illustrating one embodiment of the present invention. [Figure 7] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 8] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 9] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 10] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 11] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 12] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 13] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 14] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 15] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 16] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 17] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 18] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 19] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 20] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 21]FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 22] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 23] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 24] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 25] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 26] These are a cross-sectional TEM image and a local Fourier transform image of an oxide semiconductor. [Figure 27] 1A and 1B are diagrams showing nanobeam electron diffraction patterns of an oxide semiconductor film and an example of a transmission electron diffraction measurement device; [Figure 28] 1 shows an example of structural analysis by transmission electron diffraction measurement and a planar TEM image. [Figure 29] FIG. 1 is a conceptual diagram illustrating an example of a method for driving a display device. [Figure 30] FIG. 2 is a diagram illustrating a display module. [Figure 31] 1A and 1B are diagrams illustrating external views of an electronic device according to an embodiment. [Figure 32] 1A and 1B are diagrams illustrating external views of an electronic device according to an embodiment. [Figure 33] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Figure 34] FIG. 10 is a diagram illustrating the temperature dependence of resistivity. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments will be described with reference to the drawings. It is possible to carry out the invention in various forms and in various ways without departing from the spirit and scope of the invention. It will be readily apparent to those skilled in the art that various modifications may be made to the design and details of the present invention. The present invention is not limited to the following description of the embodiments. In the structure of the invention, reference numerals indicating the same objects are common among different drawings.

[0017] In addition, in the drawings, the size, thickness of layers, or areas may be exaggerated for clarity. Therefore, the drawings are not necessarily limited to the scale. The above is a formula and is not limited to the shapes or values shown in the drawings. Variations in signals, voltages, or currents due to timing differences, or Alternatively, it is possible to include variations in current.

[0018] In this specification and the like, a transistor refers to a transistor having a gate (gate terminal or gate electrode) and It is an element having at least three terminals including a drain and a source. The drain (drain terminal, drain region or drain electrode) and the source (source terminal, source region The drain, the channel region, and the source electrode are connected to each other. It is possible to pass a current through it.

[0019] Here, the source and drain vary depending on the structure or operating conditions of the transistor. Therefore, it is difficult to determine which is the source and which is the drain. The part that functions as a source and the part that functions as a drain are not called source or drain. One of the source and drain is referred to as the first terminal, and the other is referred to as the second terminal. It may be written.

[0020] In this specification, the ordinal numbers "first," "second," and "third" are used to avoid confusion of the elements. It should be noted that the numbers are added to avoid confusion and are not intended to be limiting.

[0021] In this specification, "A and B are connected" does not mean that A and B are directly connected. In addition to those that are electrically connected, A and B are also included. Connected to means that there is an object that has some electrical effect between A and B. When this occurs, it refers to something that enables the transmission and reception of electrical signals between A and B.

[0022] In this specification, the terms "above" and "below" that indicate placement refer to the positional relationship between components. The relationship between the components is used for convenience in the description with reference to the drawings. The terms used in the specification may be changed depending on the direction in which each component is depicted. It is not limited to phrases, but can be rephrased appropriately depending on the situation.

[0023] The layout of each circuit block in the drawings is for the purpose of explanation only. Although the diagram shows different circuit blocks realizing different functions, the actual circuits and areas In some cases, different functions may be realized within the same circuit block. The functions of each circuit block in the drawings are specified for the purpose of explanation, and Although the circuit blocks are shown, in actual circuits and areas, they are performed in one circuit block. In some cases, processing is provided to be performed by multiple circuit blocks.

[0024] Voltage refers to the potential difference between a certain potential and a reference potential (for example, ground potential). Therefore, voltage, potential, and potential difference can be rephrased as potential, voltage, and voltage difference, respectively. Voltage refers to the potential difference between two points, and potential refers to the potential at a certain point. The electrostatic energy (electrical potential energy) of a unit charge in an electrostatic field This is what is meant.

[0025] Generally, potentials and voltages are relative. Therefore, the ground potential is It is not necessarily limited to 0 volts.

[0026] In this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. Therefore, it includes the case where the angle is between -5° and 5°. "Straight" refers to the state in which two straight lines are arranged at an angle of 80° or more and 100° or less. This also includes cases where the angle is between 85° and 95°.

[0027] In this specification, when the crystal is a trigonal or rhombohedral crystal, it is expressed as a hexagonal crystal system. .

[0028] (Embodiment 1) In this embodiment, a display device which is one embodiment of the present invention will be described with reference to drawings.

[0029] <Configuration of sub-pixels in a pixel> FIG. 1A is a block diagram of a pixel portion of a display device and a circuit for driving the pixel portion. Shows.

[0030] The display device 100 shown in FIG. 1A includes a pixel portion 10, a circuit 11, and a circuit 12. The pixel section 10 includes a pixel 13. The pixel 13 includes a sub-pixel 14R, a sub-pixel 14G, and a sub-pixel 14G. It has sub-pixel 4B and sub-pixel 14W.

[0031] FIG. 1B is a block diagram for explaining the details of the pixel 13 in FIG. 1A. In FIG. 1B, the pixel 13 has sub-pixels 14R, 14G, 14B, and In addition to the sub-pixel 14W, the first wiring L1 to the fifth wiring L5 are also shown.

[0032] The pixel 13 has sub-pixels 14R, 14G, 14B, and 14W. The transistor and the capacitor are not shown. The first wiring L1 to the fifth wiring L5 are used to provide a control signal or a constant potential. Possess the ability.

[0033] Pixel 13 is a sub-pixel that transmits four colors of light, including the three primary colors RGB (red, green, and blue) and W (white). The RGB light is controlled by the additive color mixture of these lights, and the color display is performed. The sub-pixels that control the transmission of light are colored layers that convert the light from the light source into light that exhibits each color. The sub-pixel that controls the transmission of W light is , and transmits light without passing through the color filter. Note that white is obtained by additive mixing of RGB colors. In addition to white, it may be white obtained by mixing complementary colors.

[0034] It should be noted that the pixel 13 may have four types of sub-pixels, ie, RGBW sub-pixels. One embodiment of the present invention is not limited to this. One pixel may have at least four types of sub-pixels. In addition, the sub-pixels of each pixel may be different depending on the pixel. However, they may be different.

[0035] For example, the first pixel has an R subpixel, a G subpixel, and a B subpixel, and the second pixel has an R subpixel. It may have a subpixel of G, a subpixel of B, and a subpixel of W.

[0036] The sub-pixel 14R receives a first scanning signal to control the conduction state of the transistor, and supplies a first scanning signal to the capacitance element. Therefore, the first data signal is held, and the charge amount given by the first data signal is By driving the display element, it has the function of controlling the transmission of red light. The second scanning signal is applied to control the conduction state of the transistor, and the first scanning signal is applied to the capacitor. A data signal is held, and a display element is driven in accordance with the amount of charge provided by the first data signal. The sub-pixel 14B has a function of controlling the transmission of green light by switching the first scanning A second data signal is applied to the capacitor to control the conduction state of the transistor. and driving the display element in accordance with the amount of charge provided by the second data signal. The sub-pixel 14W has a function of controlling transmission of blue light. a second data signal is held by a capacitance element; By driving the display element according to the amount of charge given by the data signal, the display element can be displayed in white light. It has the function of controlling transparency.

[0037] The subpixel 14R may be referred to as the first subpixel. The subpixel 14G may be referred to as the second subpixel. The subpixel 14B may be referred to as the third subpixel. 14W is sometimes called the fourth subpixel.

[0038] In FIG. 1B, the first wiring L1 is connected to the subpixel 14R and the subpixel 14G, for example. The second wiring L2 functions as a signal line for supplying a data signal to the first wiring L1. For example, as a signal line for supplying a second data signal to the subpixels 14B and 14W, The third wiring L3 has the following function. The fourth wiring L4 has a function as a scanning line for supplying a selection signal to the first wiring L1. As a result, the subpixels 14G and 14W function as scanning lines for applying second selection signals to the subpixels 14G and 14W. The fifth wiring L5 has a function of connecting the subpixels 14R, 14G, and It functions as a capacitance line for applying a constant potential to the sub-pixel 14B and the sub-pixel 14W.

[0039] The circuit 11 shown in FIG. 1A functions as a scanning line driver circuit. (B) shows the first scanning signal and the second scanning signal being applied to the first wiring L1 and the second wiring L2. The circuit 12 shown in FIG. 1A has a function of sequentially outputting a signal line driver. Specifically, in FIG. 1B, the third wiring L3 and the fourth wiring L4 are The circuit has a function of sequentially outputting the first data signal and the second data signal to the wiring L4. 11 and circuit 12 are provided with circuits such as shift registers and have the function of outputting signals in sequence. .

[0040] In FIG. 1A, the X direction and the Y direction are shown for the sake of explanation. The direction in which the wiring L3 and the fourth wiring L4 are extended, that is, the row direction of the pixel (in FIG. 1(A) The horizontal direction of the drawing is shown as the X direction. The Y direction is the distance between the first wiring L1 and the second wiring L2. The direction in which the 2 extends, that is, the pixel column direction (the direction perpendicular to the paper surface in FIG. 1(A)), is defined as the Y direction. This is shown as follows.

[0041] In the configuration of FIGS. 1A and 1B, which is one embodiment of the present invention, the area occupied by the subpixel 14W is The area of the pixel 14R, the sub-pixel 14G, and the sub-pixel 14B is smaller than that of the pixel 14R, the sub-pixel 14G, and the sub-pixel 14B. The area occupied by a sub-pixel is the area occupied by the transistors and When the size of the capacitance element is the same as that of the gate electrode, the area of the opening can be substituted.

[0042] In the following description, the subpixel 14W may be abbreviated to the W subpixel. The subpixel 14R may be abbreviated as the R subpixel. In addition, the subpixel 14B may be abbreviated as the B subpixel. The subpixels 14R, 14G, and 14B are abbreviated as RGB subpixels. In addition, the subpixels 14R, 14G, 14B, and 14C may be described as subpixels 14R, 14G, 14C, and 14D. W may be abbreviated to RGBW (red, green, blue, white) subpixels.

[0043] By making the area occupied by the W sub-pixel smaller than the area occupied by each of the RGB sub-pixels, In contrast, each of the RGB sub-pixels can be enlarged, and the area of the aperture of the RGB sub-pixels can be increased. Therefore, when color display is performed using RGB sub-pixels, Color display can be achieved without reducing color saturation.

[0044] In addition, the W sub-pixel has a color filter that is provided in the RGB sub-pixel to display a predetermined color. Therefore, the intensity of light transmitted through the W sub-pixel is the same as that transmitted through each of the RGB sub-pixels. Therefore, even if the area of the W subpixel is smaller than the other subpixels, the intensity of the light passing through the W subpixel is As a result, even if the area of the W subpixel is reduced, the color intensity can be kept in balance. The white balance of the image obtained by the color display is not significantly changed. The area occupied by the sub-pixels can be made smaller than the area occupied by each of the RGB sub-pixels. do.

[0045] The white light obtained by passing through the RGB sub-pixels is light that has passed through a color filter. The white light is obtained when the intensity of the light emitted from the light source is smaller than that of the light emitted from the light source. In addition, the white color obtained from the W sub-pixel is obtained when the light from the light source does not pass through the color filter. Therefore, the light intensity obtained in one embodiment of the present invention is white. The white obtained from the RGBW sub-pixels is brighter than the white obtained from the RGB sub-pixels. In other words, the white color obtained from the RGBW sub-pixels is This is white with reduced intensity reduction. Therefore, one aspect of the present invention uses RGBW sub-pixels. In this configuration, white light is obtained without passing through a color filter, so the light is When emitting light of the same intensity to obtain white, white is obtained by additive color mixing using RGB sub-pixels. As a result, the display device can reduce power consumption. This can be achieved.

[0046] The area occupied by the W sub-pixel is determined by the color filters of the RGB sub-pixels. Although it depends on the amount of light attenuation, it should be at least 1 / 3 of the area of each of the other RGB sub-pixels, but less than the same size. Preferably, the area occupied by the W subpixel is at least half that of each of the other RGB subpixels. Above all, the area should be less than the same size.

[0047] In the configuration of FIGS. 1A and 1B, which is one embodiment of the present invention, the subpixels 14R and 14 The sub-pixels 14G, 14B, and 14W are arranged in two rows and two columns. The position of the sub-pixels arranged in two rows and two columns is an example. The positions of the pixel 14R and the sub-pixel 14G can be changed as appropriate, for example by swapping them.

[0048] By arranging the RGBW sub-pixels in a pixel as shown in Figure 1(A) and (B), the RGBW sub-pixels Compared to when pixels are arranged in stripes, the number of wiring lines, such as data lines, scanning lines, and capacitance lines, is reduced. It is possible.

[0049] For example, if the display device is a liquid crystal display device and the four RGBW sub-pixels are arranged in a stripe pattern, There are four data lines, one scanning line, and one capacitance line, for a total of six wires. It is necessary to control the pixels.

[0050] On the other hand, in the configuration of FIGS. 1A and 1B, which is one embodiment of the present invention, the number of data lines is two, and the number of scanning lines is two. There are two lines and one capacitance line, so pixels can be controlled using a total of five wires. Therefore, it is possible to reduce the area occupied by the wiring connected to the pixel having the RGBW sub-pixels. By reducing the area occupied by wiring, the RGB sub-pixels can be made larger. Therefore, the area of the aperture of each RGB sub-pixel can be increased. When emitting light of the same intensity to obtain white light, the light source can be weakened, so power consumption is reduced. The force can be reduced.

[0051] In the display device according to one embodiment of the present invention, the RGBW subpixels are ) is arranged in a matrix in the X and Y directions as shown in FIG. The arrangement of the sub-pixels is not limited to the configuration shown in Fig. 2(A) and can be changed as appropriate. For example, the RGBW sub-pixels may be arranged as shown in FIG. 2(B).

[0052] In the configuration according to one aspect of the present invention, the area occupied by the subpixel 14W is divided into the areas occupied by the subpixels 14R, It is sufficient if the area is smaller than the area occupied by the pixel 14G and the sub-pixel 14B. In this case, ) the RGBW sub-pixels can be arranged in a stripe pattern as shown in Figure 3. As shown in (B), the sub-pixels 14R, 14G, and 14B are further divided into sub-pixels. Alternatively, in Figures 3(A) and (B), a stripe arrangement in the Y direction can be used. As shown in Figure 3(C), the pixels are arranged in stripes in the X direction. RGBW sub-pixels in 13 may be arranged.

[0053] <Data signals given to pixels> The first data signal and the second data signal to be given to each of the RGBW sub-pixels of the pixel are The first data signal and the second data signal are RGBW data signals, which are the three primary colors of RGB plus W. The data signal may be generated based on the data signals of the three primary colors of RGB. The first data signal and the second data signal are generated using the configuration of the block diagram shown in FIG. That's fine.

[0054] FIG. 33A shows an example in which, in addition to the display device 100, a display controller 200, The signal conversion circuit 210 and the backlight unit 230 are shown. The display device 100 has a data signal calculation circuit 220. Note that FIG. 33(A) shows a case where the display device 100 is a liquid crystal display. 2 shows an example of a display device, and shows a backlight unit 230 as a light source.

[0055] The display controller 200 generates RGB data signals (RGB_data in the figure), The signal conversion circuit 210 converts the RGB data signal into RGBW data. signal (RGBW_data in the figure) and output it to the display device 100. The signal conversion circuit 210 converts the backlight signal into a In order to control the light intensity of the backlight (in the drawing, back light) of the unit 230 It has the function of generating the backlight control signal BL_cont for the backlight unit. The backlight control signal BL_cont is used as the light source of the display device 100. The backlight unit has a function to control the intensity of the backlight. 230 has a plurality of light sources that can be divided and controlled corresponding to a plurality of sub-pixels, and each light source has an individual With this configuration, the RGBW data signal can be controlled to have a high or low intensity of light. The intensity of light can be adjusted accordingly, thereby achieving further reduction in power consumption.

[0056] The data signal calculation circuit 220 included in the signal conversion circuit 210 has a look-up table. Based on the lookup table, the RGB data signal is converted into an RGBW data signal. With this configuration, it is possible to obtain the information without performing complex calculation processing. It is possible to convert RGB data signals into RGBW data signals. The data signal calculation circuit 220 performs calculations based on the RGB data signals, and outputs RGBW data. The configuration may be such that a data signal is generated.

[0057] The backlight unit 230 is controlled by a backlight control signal BL_cont. As an example, the backlight unit 230 has a gray scale value of the W data signal. When the intensity of the light transmitted through the W sub-pixel is greater than the grayscale value of the data signal, that is, when the intensity of the light transmitted through the W sub-pixel is greater than the RGB When the intensity of the light transmitted through each sub-pixel is greater than the intensity of the light from the corresponding light source, the light is reduced. In addition, the backlight unit 230 is configured such that the grayscale value of the W data signal is If the difference is smaller than the gray level of the signal, the light of the corresponding light source is controlled to be intensified. By doing so, the decrease in the intensity of light passing through the W sub-pixel is suppressed. The amount of light can be adjusted appropriately, which reduces power consumption. The comparison of the gradation values by the pixel signal may be calculated based on the average value of all pixels, or may be calculated based on the average value of any point. Alternatively, the calculation may be performed based on the average value of the pixels.

[0058] The W data signal is generated separately from the RGB data signals, as shown in FIG. 33(B). In this configuration, the data signal calculation circuit 220 corrects the RGB data signals. Since this is not necessary, the amount of calculation required by the data signal calculation circuit 220 can be reduced. In this case, the RGB data signal is not corrected, so the backlight unit is adjusted based on the W data signal. The light from the light source can be adjusted by the light source 230, thereby reducing power consumption.

[0059] <Display device configuration> As described above, the area of the opening of the W subpixel is made smaller than the area of the opening of the RGB subpixel. The sub-pixels are arranged in two rows and two columns to reduce the number of wirings that control the pixels. In addition, in one embodiment of the present invention, a semiconductor film of a transistor included in each subpixel is formed of an oxide semiconductor. The electrodes constituting the capacitor element are made of a conductive film having light-transmitting properties. Therefore, the configuration of a transistor and a capacitor included in a subpixel will be described with reference to the drawings. .

[0060] First, FIG. 4A shows a block diagram of the display device 100 in more detail than FIG. 1A. The display device 100 shown in FIG. 1A includes a pixel section 10, a circuit 11, and a circuit 12, which are arranged in parallel. m (m is a natural number) running wires arranged in parallel or approximately parallel to each other, and the potential of which is controlled by a circuit 11. The scanning lines 15 are arranged parallel or approximately parallel to each other, and the potential is controlled by the circuit 12. The pixel section 10 has n signal lines 16 (n is a natural number) arranged in a matrix. The pixel 13 has a plurality of pixels 13 arranged in two rows and two columns. 4. Capacitor lines 11 are arranged parallel or approximately parallel to each other along the signal line 16. It has 7.

[0061] The display device includes a display controller, a signal conversion circuit, a power supply circuit, and other components arranged on separate substrates. It includes a display unit, a backlight unit, etc. and is sometimes called a display module.

[0062] 4B and 4C show circuit patterns that can be used for the sub-pixel 14 of the display device shown in FIG. 4A. 1 shows an example of a road configuration.

[0063] The sub-pixel 14 shown as an example in FIG. 4B is a sub-pixel included in the liquid crystal display device, and is a liquid crystal element. The semiconductor device includes a capacitor 23, a transistor 21, and a capacitor 22.

[0064] The potential of one of the pair of electrodes of the liquid crystal element 23 is set appropriately according to the specifications of the sub-pixel 14 . The alignment state of the liquid crystal element 23 is set by the written data. A common potential (common potential: V com) may be provided. In addition, one of the pair of electrodes of the liquid crystal element 23 for each sub-pixel 14 in each row may be given different potentials.

[0065] The liquid crystal element 23 controls the transmission or non-transmission of light by the optical modulation effect of the liquid crystal. The optical modulation effect of the liquid crystal is due to the electric field (horizontal direction) applied to the liquid crystal. The liquid crystal element 2 is controlled by a vertical electric field or a diagonal electric field. 3. Nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, thermotropic liquid crystal Examples of the liquid crystal include ferroelectric liquid crystal, lyotropic liquid crystal, ferroelectric liquid crystal, and antiferroelectric liquid crystal.

[0066] The display device having the liquid crystal element 23 can be driven in various modes, such as TN mode, VA mode, ASM(Axially Symmetric Aligned Micro-cell ) mode, OCB (Optically Compensated Birefring ence) mode, MVA mode, PVA (Patterned Vertical A lignment) mode, IPS mode, FFS mode, or TBA (Transv However, you can also use the (Underscore Bend Alignment) mode. There is no limitation, and various liquid crystal elements and driving methods thereof can be used.

[0067] In addition, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent The liquid crystal element may be constructed from these. The liquid crystal that exhibits the blue phase has a short response time of 1 msec or less. Furthermore, since the liquid crystal exhibiting the blue phase is optically isotropic, no alignment treatment is required. The viewing angle dependency is small.

[0068] In the configuration of the subpixel 14 shown in FIG. 4B, the source electrode and the drain electrode of the transistor 21 One of the electrodes is connected to the signal line 16, and the other is connected to the other of the pair of electrodes of the liquid crystal element 23. The gate electrode of the transistor 21 is connected to the scanning line 15. The data signal is written by switching the data signal ON or OFF. It has a function.

[0069] In the configuration of the subpixel 14 shown in FIG. 4B, one of the pair of electrodes of the capacitor element 22 is at a potential The other end is connected to the other of the pair of electrodes of the liquid crystal element 23. The value of the potential of the capacitor line 17 is set appropriately according to the specifications of the sub-pixel 14. The element 22 functions as a storage capacitor that stores the written data.

[0070] For example, in a display device having the sub-pixels 14 shown in FIG. 4B, the circuit 11 controls the sub-pixels 14 in each row. 4 are selected in sequence, and the transistor 21 is turned on to write the data signal.

[0071] The sub-pixel 14 into which data has been written is in a holding state when the transistor 21 is turned off. By performing this process row by row, an image can be displayed.

[0072] As another example, the sub-pixel 14 shown in FIG. 4C is a sub-pixel included in a light-emitting display device. The pixel includes a transistor 31, a transistor 32, a transistor 34, and a capacitance element 3 3 and a light-emitting element 35.

[0073] One of the source electrode and the drain electrode of the transistor 31 is connected to a signal line to which a data signal is applied. The gate electrode of the transistor 31 is connected to the scanning line 15. do.

[0074] The transistor 31 is turned on or off to write a data signal. It has the function of controlling the above.

[0075] One of the source and drain electrodes of the transistor 34 is a wiring that functions as an anode line. The other of the source electrode and the drain electrode of the transistor 34 is connected to the line 37. The gate electrode of the transistor 34 is connected to one electrode of the transistor 35. The other of the source electrode and the drain electrode of the capacitor 31 and one electrode of the capacitor element 33 are connected to the do.

[0076] The transistor 34 controls the amount of current flowing through the light emitting element 35 according to the data held in the gate. It has the function of controlling the above.

[0077] One of the source and drain electrodes of the transistor 32 is given a data reference potential. The other of the source electrode and the drain electrode of the transistor 32 is connected to the wiring 36. The transistor 35 is connected to one electrode of the capacitor 35 and the other electrode of the capacitor 33. The gate electrode of the transistor 32 is connected to the scanning line 15 .

[0078] The transistor 32 has a function of adjusting the current flowing through the light-emitting element 35. When the internal resistance of the light emitting element 35 increases due to deterioration of the element 35, the transistor 32 The current flowing through the wiring 36 to which one of the source electrode and the drain electrode is connected is monitored. By doing so, the current flowing through the light emitting element 35 can be corrected. The potential can be set to, for example, 0V.

[0079] One of the pair of electrodes of the capacitor 33 is connected to the source electrode and the drain electrode of the transistor 31. The other of the pair of electrodes of the capacitor 33 is connected to the gate electrode of the transistor 34. is connected to the other of the source electrode and drain electrode of the transistor 34 and one of the electrodes of the light emitting element 35. connected to the electrode.

[0080] In the configuration of the sub-pixel 14 shown in FIG. 4C, the capacitive element 33 stores the written data. It functions as a storage capacitor.

[0081] One of the pair of electrodes of the light emitting element 35 is connected to the source electrode and drain electrode of the transistor 34. On the other hand, the other electrode of the capacitor 33 and the source electrode and drain electrode of the transistor 32 The other of the pair of electrodes of the light emitting element 35 is connected to the other of the pair of electrodes. The wiring 38 is connected to the wiring 38.

[0082] The light-emitting element 35 may be, for example, an organic electroluminescence element (also called an organic EL element). However, the light-emitting element 35 is not limited to this, and inorganic An inorganic EL element made of a material may also be used.

[0083] A high power supply potential VDD is applied to one of the wiring 37 and the wiring 38, and a low power supply potential VDD is applied to the other. In the configuration shown in FIG. 4C, the high power supply potential VSS is applied to the wiring 37. The wiring 38 is configured to apply a low power supply potential VSS to the wiring DD.

[0084] In the display device having the sub-pixels 14 of FIG. 4C, the sub-pixels 14 of each row are sequentially The data signal is written by selecting the data bit and turning on the transistor 31.

[0085] The sub-pixel 14 into which data has been written is in a holding state when the transistor 31 is turned off. Furthermore, since the transistor 31 is connected to the capacitance element 33, the written The data can be retained for a long time. The amount of current flowing between the drain electrode and the gate electrode is controlled, and the light emitting element 35 emits a light according to the amount of current flowing. By repeating this process row by row, an image can be displayed.

[0086] In addition, in FIG. 4(B) and FIG. 4(C), the liquid crystal element 23 and the light emitting element 35 are used as the display element. However, one embodiment of the present invention is not limited to this. For example, EL (electroluminescence) elements (organic and inorganic materials) EL elements, organic EL elements, inorganic EL elements), LEDs (white LEDs, red LEDs, green color LEDs, blue LEDs, etc.), transistors (transistors that emit light according to the current), electron emission element, liquid crystal element, electronic ink, electrophoretic element, grating light valve (GL V), plasma display panels (PDP), MEMS (microelectromechanical systems) Display elements using the Digital Micromirror Device (DMD), D MS (Digital Micro Shutter), IMOD (Interference Modulation shutter-type MEMS display element, optical interference-type MEMS display element, Electrowetting elements, piezoelectric ceramic displays, carbon nanotubes, Displays whose contrast, brightness, reflectance, transmittance, etc. change due to electromagnetic effects, such as An example of a display device using an EL element is an EL display. An example of a display device using electron-emitting elements is a field emission device. Flat panel display (FED) or SED type flat panel display (SED: Surface-c Induction Electron-emitter Display An example of a display device using a liquid crystal element is a liquid crystal display (transmissive liquid crystal display). Transflective LCD displays, reflective LCD displays, direct-view LCD displays, projection LCD displays A type of display device that uses electronic ink or electrophoretic elements. Examples include electronic paper. When realizing a display, part or all of the pixel electrodes function as reflective electrodes. For example, a part or the whole of the pixel electrode may be made of aluminum. In this case, the reflective electrode may have a metal such as SRAM. This allows further reduction in power consumption. can be done.

[0087] <Configuration on the element substrate and the opposing substrate> Next, the configuration of the transistor and the capacitor included in the sub-pixel will be described. In one embodiment, a semiconductor film of a transistor included in each subpixel is an oxide semiconductor film, and a capacitor element The electrode constituting the element is characterized in that it is made of a conductive film having light-transmitting properties. In one embodiment of the present invention, the light-transmitting conductive film included in the capacitor may be formed by increasing the number of steps. In the following, the element substrate side is provided with a material that can be formed without any problem. and a color filter provided on the opposing substrate side. The configuration of the sub-pixels will be described in detail.

[0088] In the following description, the display device will be described as a liquid crystal display device. 5B is a top view showing the arrangement of members on the element substrate side in the pixel 13. 6 shows the circuit configuration corresponding to the plan view. 7 shows a top view illustrating the arrangement of the components on the opposing substrate side, which corresponds to the side view of FIG. ), and the area between the chain lines AB and C- on the element substrate side and the opposing substrate side shown in the top view of FIG. The cross section of section D is shown.

[0089] In FIG. 5A, the conductive films 15_m and 15_m+1 functioning as scanning lines are The conductive film functions as a signal line and extends in a direction substantially perpendicular to the conductive film. The conductive films 16_n and 16_n+1 functioning as the scanning lines and the conductive film 17p functioning as the capacitance line are The scanning lines are provided so as to extend in a direction substantially perpendicular to the conductive film that functions as a scanning line. The functioning conductive films 15_m and 15_m+1 are connected to a circuit 11( 4(A).) and the conductive film 16_n and 16_n+1 is connected to the circuit 12 (see FIG. 4(A)) that functions as a signal line driver circuit. The conductive film 17p, which functions as a capacitance line, is connected to a circuit (not shown) that applies a fixed potential. connected to the

[0090] In the top view shown in FIG. 5A, the pixel 13 includes the subpixels 14R, 14G, and 14B and 14W. In the subpixel 14R, the oxide semiconductor film 41 R, conductive film 45R, opening 47R, conductive film 49R, metal oxide film 43RB, opening 50R In addition, the subpixel 14G has an oxide semiconductor film 41G, a conductive film 45G, an opening 47 The subpixel 14B has a conductive film 49G, a metal oxide film 43GW, and an opening 50GW. In the example, the oxide semiconductor film 41B, the conductive film 45B, the opening 47B, the conductive film 49B, and the metal oxide The subpixel 14W has an oxide semiconductor film 41W, an oxide semiconductor film 43RB, and an opening 50RB. Conductive film 45W, opening 47W, conductive film 49W, metal oxide film 43GW, opening 50GW Has.

[0091] 5B, the sub-pixel 1 included in the pixel 13 corresponding to the top view shown in FIG. 5A is 1 shows an example of a circuit configuration for the sub-pixels 14R, 14G, 14B, and 14W. The element 14R includes a transistor 21R, a capacitor element 22R, and a liquid crystal element 23R. The sub-pixel 14G includes a transistor 21G, a capacitor 22G, and a liquid crystal element 23G. The sub-pixel 14B includes a transistor 21B, a capacitor 22B, and a liquid crystal element 23B. In addition, the sub-pixel 14W includes a transistor 21W, a capacitor element 22W, and a liquid crystal element 23W. Has.

[0092] The transistor 21R (21G, 21B or 21W) shown in FIG. 5B is a scanning line. The conductive film functions as a signal line and the conductive film functions as a signal line. The transistor 21R (21G, 21B or 21W) is a conductive layer that functions as a gate electrode. film 15_m (or 15_m+1), a gate insulating film (not shown in FIG. 5(A)), a gate An oxide semiconductor film (41R, 41G, 41R) in which a channel region is formed on the insulating film is formed. B or 41W), a pair of conductive films 16_n functioning as a source electrode and a drain electrode (or 16_n+1), and conductive film 45R (45G, 45B or 45W). .

[0093] The conductive film 15_m (or 15_m+1) can also function as a scanning line. The region overlapping with the oxide semiconductor film 41R (41G, 41B, or 41W) functions as a transistor. It functions as the gate electrode of the transistor 21R (21G, 21B or 21W). The conductive film 16_n (or 16_n+1) is a conductive film that functions as a signal line. The region overlapping with the oxide semiconductor film 41R (41G, 41B, or 41W) is a transistor. As the source or drain electrode of transistor 21R (21G, 21B, or 21W) In addition, in FIG. 5A, the conductive film functioning as the scan line has a top surface shape The end portion is located outside the end portion of the oxide semiconductor film 41R (41G, 41B, or 41W). Therefore, the conductive film that functions as the scanning line is located at the As a result, the oxide semiconductor film included in the transistor functions as a light-shielding film. When light is not irradiated onto 41R (41G, 41B or 41W), the electrical characteristics of the transistor are Fluctuations can be suppressed.

[0094] Also, on the metal oxide film 43RB (or 43GW), a conductive film 49 is formed via an insulating film. R (49G, 49B or 49W) is provided. In the insulating film provided on the insulating film 50RB (or 43GW), an opening 50RB (or 50GW) is formed. In the opening 50RB (or 50GW), the metal oxide film 43RB (or 43 GW) contacts the nitride insulating film (not shown in FIG. 5) included in the insulating film.

[0095] The capacitance element 22R (22G, 22B or 22W) is made of a metal oxide film 43RB (or 3GW) and the conductive film 49R (49G, 49B or 49W) are formed in the overlapping region. The metal oxide film 43RB (or 43GW) and the conductive film 49R (49G, 49B or That is, the capacitive element 22R (22G, 22B or 22W) is transparent. W) has translucency.

[0096] The conductive film 49R (49G, 49B or 49W) functions as a pixel electrode. The conductive film 49R (49G, 49B or 49W) is formed in the opening 47R (47G, 47B or In the case of 47W, the conductive film 45R (45G, 45B or 45W) is connected. That is, the transistor 21R (21G, 21B or 21W), the capacitance element 22R (22G , 22B or 22W) and the conductive film 49R (49G, 49B or 49W) are Connect to.

[0097] Since the capacitive element 22R (22G, 22B, or 22W) is light-transmitting, (14G, 14B or 14W) in the capacitive element 22R (22G, 22B or 22W ) can be formed large (large area). Therefore, while increasing the aperture ratio, typically It is possible to increase the capacitance to 50% or more, preferably 60% or more, and the capacitance value is increased. For example, a display device with high resolution, such as a liquid crystal display device, can be obtained. In this case, the area of the pixel becomes smaller, and the area of the capacitance element also becomes smaller. In a display device with a small capacitance, the amount of charge stored in the capacitance element is small. Since the capacitance element 22R (22G, 22B or 22W) shown in the above embodiment is transparent, By providing the capacitance element in the pixel, it is possible to obtain a sufficient capacitance value in each pixel while increasing the aperture ratio. Typically, pixel densities are 100 ppi or higher, or even 200 ppi or higher. Furthermore, it can be suitably used in high-resolution display devices having a resolution of 300 ppi or more.

[0098] In addition, in a liquid crystal display device, the larger the capacitance value of the capacitance element, the more the capacitance of the capacitance element increases when an electric field is applied. In this case, the period during which the alignment of the liquid crystal molecules in the liquid crystal element can be kept constant can be extended. When displaying a still image, the period can be extended, so the number of times the image data is rewritten can be reduced. It is possible to reduce the power consumption. The structure shown in FIG. 1 allows the aperture ratio to be increased even in high-resolution display devices. This allows for efficient use of light from light sources such as backlights, reducing the power consumption of display devices. It is possible.

[0099] In FIG. 5B, the transistor 21R (21G, 21B or 21W) is a gate It is sufficient to have the gate on at least one side of the semiconductor film, but it is also possible to have the gate sandwiched between the semiconductor film. If one of the pair of gates is a back gate, The same potential may be applied to the normal gate and the back gate, or the back gate may be applied to the normal gate and the back gate. A fixed potential such as a ground potential may be applied only to the gate. By controlling the height of the buffer layer, the threshold voltage of the transistor can be controlled. By providing a gate, the channel formation area increases, and the drain current increases. In addition, by providing a back gate, a depletion layer is easily formed in the semiconductor film. , the S value can be improved.

[0100] In addition, in FIG. 5B, the transistor 21R (21G, 21B or 21W) By having a single gate, it is a single gate structure having a single channel forming region. However, one embodiment of the present invention is not limited to this structure. Any or all of R (21G, 21B, or 21W) may be connected to multiple gates. By having the above, a multi-gate structure having a plurality of channel forming regions may be obtained.

[0101] 6, which is a top view of the opposing substrate side corresponding to the top view of FIG. 5(A), the pixel 13 is 1 shows an example of the arrangement of the sub-pixels 14R, 14G, 14B, and 14W. The sub-pixel 14R has a color filter 53R and an opening 55R. The sub-pixel 14B has a color filter 53G and an opening 55G. The subpixel 14W includes a filter 53B and an opening 55B. W, has an opening 55W.

[0102] The color filter 53R (53G or 53B) changes the light from the light source that passes through it into a predetermined color. The opening 55R (55G or 55B) is a layer for changing the light into a color filter. The opening is for transmitting light to the filter 53R (53G or 53B).

[0103] The light-transmitting layer 53W is a layer for transmitting light from the light source. This is an opening for transmitting light to the optical layer 53W.

[0104] Next, cross-sectional views taken along chain lines AB and CD in FIGS. 5(A) and 6 are shown in FIG.

[0105] Here, as shown in FIG. 7, the components between the substrate 60 serving as the element substrate and the substrate 90 serving as the opposing substrate are This will be explained below.

[0106] First, each member on the substrate 60 that serves as the element substrate will be described.

[0107] A conductive film 62 is formed on the substrate 60. The conductive film 62 is a conductive film 15_m. It functions as the gate electrode of transistor 21B.

[0108] There is no particular restriction on the material of the substrate 60, but it should be at least durable enough to withstand the subsequent heat treatment. For example, glass substrate, ceramic substrate, quartz substrate, sapphire substrate, A metal substrate or the like may be used as the substrate 60. Also, a substrate made of silicon or silicon carbide may be used. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, It is also possible to use an SOI substrate, etc., and a semiconductor element is provided on such a substrate. may be used as the substrate 60. When a glass substrate is used as the substrate 60, 6th generation (1500mm x 1850mm), 7th generation (1870mm x 2200mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 2800mm), By using large area substrates such as 10th generation (2950mm x 3400mm), large displays can be realized. A device can be fabricated.

[0109] In addition, a flexible substrate is used as the substrate 60, and a transistor is formed directly on the flexible substrate. Alternatively, a separation layer may be provided between the substrate 60 and the transistor. After completing a part or all of the element part on the substrate, it is separated from the substrate 60 and transferred to another substrate. In this case, the transistor is mounted on a substrate with poor heat resistance or a flexible substrate. can also be reproduced.

[0110] The conductive film 62 may be made of aluminum, chromium, copper, tantalum, titanium, molybdenum, or titanium. or an alloy containing the above-mentioned metal elements, or It can be formed by using an alloy of a combination of metal elements. Alternatively, the conductive film 6 may be formed of one or more metal elements selected from the group consisting of fluorine, fluorine, arsenic ... 2 may be a single layer structure or a laminated structure of two or more layers. For example, aluminum containing silicon Single layer structure of titanium film, double layer structure of titanium film on aluminum film, titanium nitride film on 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; Two-layer structure in which a tungsten film is laminated on a tantalum nitride film or a tungsten nitride film, A titanium film is formed on the titanium film, and an aluminum film is laminated on the titanium film. There are also aluminum, titanium, tantalum, tungsten, molybdenum, etc. an alloy film made of a combination of one or more selected from the group consisting of silicon, chromium, neodymium, and scandium; Alternatively, a nitride film may be used.

[0111] The conductive film 62 may be made of indium tin oxide, indium oxide containing tungsten oxide, Indium zinc oxide with tungsten oxide, indium oxide with titanium oxide, acid Indium tin oxide containing titanium oxide, indium zinc oxide, and silicon oxide doped indium A light-transmitting conductive material such as indium tin oxide can also be used. A laminated structure of a conductive material having optical properties and the above metal element may also be used.

[0112] An insulating film 64 and an insulating film 66 are formed on the substrate 60 and the conductive film 62. 4. The insulating film 66 functions as a gate insulating film for the transistor 21B.

[0113] The insulating film 64 may be, for example, silicon nitride, silicon nitride oxide, aluminum nitride, or nitride. It is preferable to form the insulating film using a nitride such as aluminum oxide.

[0114] The insulating film 66 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. Silicon, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn-based metal oxide The insulating film 66 may be formed of a hafnium oxide or the like, and may be formed as a laminated layer or a single layer. HfSiO x ), nitrogen-doped hafnium silicate (HfSi x O y N z ), nitrogen-doped hafnium aluminate (HfAl x O y N z ), Chloride By using high-k materials such as fluorine and yttrium oxide, the gate of the transistor can be Leaks can be reduced.

[0115] The total thickness of the insulating film 64 and the insulating film 66 is preferably 5 nm or more and 400 nm or less. The thickness is preferably 10 nm or more and 300 nm or less, more preferably 50 nm or more and 250 nm or less. .

[0116] An oxide semiconductor film 68 and a metal oxide film 70 are formed on the insulating film 66. The conductive film 68 is an oxide semiconductor film 41B, and is formed at a position where it overlaps with the conductive film 62. The metal oxide film 70 functions as a channel region of the transistor 21B. The conductive film 76 is connected to the capacitor element 22G and functions as an electrode of the capacitor element 22W. , and the conductive film 17p functions as a capacitance line.

[0117] The oxide semiconductor film 68 and the metal oxide film 70 are typically made of In—Ga oxide, In- Zn oxide, In-M-Zn oxide (M is Al, Ti, Ga, Y, Zr, La, Ce, N The oxide semiconductor film 68 and the metal oxide film 70 are made of, for example, It has translucency.

[0118] When the oxide semiconductor film 68 and the metal oxide film 70 are In-M-Zn oxides, The atomic ratio of In and M is 100 atoms, excluding Zn and O. c%, In is 25 atomic % or more, M is less than 75 atomic %, and more preferably Preferably, In is 34 atomic % or more and M is less than 66 atomic %.

[0119] The oxide semiconductor film 68 and the metal oxide film 70 preferably have an energy gap of 2 eV or more. The energy gap is preferably 2.5 eV or more, and more preferably 3 eV or more. By using an oxide semiconductor with a wide band gap, the off-state current of a transistor can be reduced. do.

[0120] The thickness of the oxide semiconductor film 68 and the metal oxide film 70 is preferably 3 nm or more and 200 nm or less. Preferably, the thickness is 3 nm or more and 100 nm or less, and more preferably, 3 nm or more and 50 nm or less.

[0121] The oxide semiconductor film 68 and the metal oxide film 70 are made of In:Ga:Zn=1:1:1, In In-Ga-Zn oxide with an atomic ratio of Ga:Zn=1:1:1.2 or 3:1:2 The atomic ratio of the oxide semiconductor film 68 to the metal oxide film 70 can be Each of these includes a variation of ±20% of the atomic ratios listed above as an error.

[0122] The oxide semiconductor film 68 and the metal oxide film 70 may have, for example, a non-single crystal structure. The single crystal structure is, for example, CAAC-OS (C Axis Aligned Cr) as described later. Crystalline Oxide Semiconductor), polycrystalline structure, described later In non-single crystal structures, the amorphous structure is the most defective. The defect density of the oxide semiconductor film 68 is high, and the defect density of the CAAC-OS is the lowest. , and the metal oxide film 70 have the same crystallinity.

[0123] The oxide semiconductor film 68 and the metal oxide film 70 are divided into an amorphous region and a microcrystalline region. The nanocrystalline structure has two or more of the following regions: a polycrystalline structure region, a CAAC-OS region, and a single-crystalline structure region. The mixed film may be a film having an amorphous structure and a microcrystalline structure. , a polycrystalline structure region, a CAAC-OS region, and a single-crystalline structure region. It may have a laminated structure of the region.

[0124] When the oxide semiconductor film 68 contains silicon or carbon, which is one of the Group 14 elements, The oxygen vacancies increase in the oxide semiconductor film 68, causing it to become n-type. Concentrations of silicon and carbon in the conductive film 68 (concentrations obtained by secondary ion mass spectrometry) , 2 × 10 18 atoms / cm 3 Less than or equal to 2 x 10 17atoms / cm 3 The following applies.

[0125] In addition, in the oxide semiconductor film 68, an alkali metal Or the concentration of alkaline earth metals is 1 x 10 18 atoms / cm 3 Below, preferably 2 x10 16 atoms / cm 3 The alkali metals and alkaline earth metals are oxidized When they bond with semiconductors, they can generate carriers, which increases the off-state current of the transistor. For this reason, the alkali metal or alkaline earth metal in the oxide semiconductor film 68 It is preferable to reduce the concentration of metals.

[0126] When nitrogen is contained in the oxide semiconductor film 68, electrons serving as carriers are generated. As a result, the nitrogen-containing oxide semiconductor The transistor tends to be normally on. It is preferable that the nitrogen content is reduced as much as possible. For example, it is preferable that the nitrogen content is reduced as much as possible by secondary ion mass spectrometry. The resulting nitrogen concentration is 5 x 10 18 atoms / cm 3 It is preferable to do the following:

[0127] The oxide semiconductor film 68 is an oxide semiconductor film with low carrier density. The compound semiconductor film 68 has a carrier density of 1×10 17 pieces / cm 3 Less than 1 × 10 15 pieces / cm 3 or less, more preferably 1 × 10 13 pieces / cm 3 The following is particularly preferably 8 x1011 / cm 3 less than 1×10 11 / cm 3 Less than, preferably is 1 x 10 10 / cm 3 Less than 1 x 10 -9 / cm 3 Using the above oxide semiconductor film, do.

[0128] In addition, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use an appropriate composition depending on the required properties (mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of a transistor, the carrier density and the impurity concentration of the oxide semiconductor film 68 are The degree of crystallization, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. must be appropriate. is preferred.

[0129] The oxide semiconductor film 68 has interface characteristics with the oxide semiconductor film such as the insulating film 66 and the insulating film 78. Since the oxide semiconductor film 68 is in contact with a film formed of a material capable of improving the conductivity, The transistor having the oxide semiconductor film 68 functions as a semiconductor and has excellent electrical characteristics. do.

[0130] The oxide semiconductor film 68 is formed of an oxide semiconductor having a low impurity concentration and a low density of defect states. By using the film, a transistor having excellent electrical characteristics can be manufactured, which is preferable. Here, a low impurity concentration and a low defect level density (low oxygen vacancies) are called high purity. It is called pure or substantially pure. In semiconductors, the carrier density can be reduced because there are few carrier sources. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film has a threshold voltage. When the electrical characteristics are such that the voltage is negative (also called normally on), In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a defect level. Because of the low density, the trap level density may also be low. The oxide semiconductor film, which is essentially highly pure and intrinsic, has a significantly small off-state current and a channel width of 1×1. 0 6 Even in a device with a channel length of 10 μm, the voltage between the source and drain electrodes In the drain voltage range of 1V to 10V, the off-state current was measured by the semiconductor parameter analyzer. Below the riser measurement limit, i.e., 1×10 -13 It can achieve a characteristic of A or below. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film has a change in electrical characteristics. In some cases, the transistor can have low voltage and high reliability. Charges trapped in the trap level take a long time to disappear, and they act like fixed charges. Therefore, the channel is formed in the oxide semiconductor film having a high density of trap states. The transistor in which the region is formed may have unstable electrical characteristics. , hydrogen, nitrogen, alkali metals, or alkaline earth metals.

[0131] The metal oxide film 70 is formed by processing an oxide semiconductor film that is formed at the same time as the oxide semiconductor film 68. Therefore, the metal oxide film 70 contains the same metal element as the oxide semiconductor film 68. The oxide semiconductor film 68 may have a crystal structure similar to or different from that of the oxide semiconductor film 68. However, the metal oxide film 70 is formed at the same time as the oxide semiconductor film 68. By adding impurities to the oxide semiconductor film to create oxygen vacancies, the film becomes conductive. The oxide semiconductor film functions as an electrode of a capacitor. In addition, impurities such as boron, phosphorus, tin, antimony, and rare gases can be used instead of hydrogen. The film may contain elements, alkali metals, alkaline earth metals, etc. Alternatively, the film may contain metal oxides. A film 70 is formed at the same time as the oxide semiconductor film 68, and is oxidized due to plasma damage or the like. The metal oxide film 70 is a film in which electron vacancies are formed and the conductivity is increased. This film is formed at the same time as the semiconductor film 68, contains impurities, and is not susceptible to plasma damage. Oxygen vacancies are formed by the above-mentioned factors, and the conductivity of the film is increased.

[0132] In an oxide semiconductor with oxygen vacancies, hydrogen enters the oxygen vacancy sites, and the conduction band As a result, the oxide semiconductor becomes more conductive and becomes a conductor. An oxide semiconductor that has been made into a conductor is called a metal oxide film, but it is also sometimes called an oxide conductor. Generally, oxide semiconductors have a large energy gap and are therefore transparent to visible light. On the other hand, an oxide conductor is an oxide semiconductor that has a donor level near the conduction band. Therefore, the influence of absorption due to the donor level is small, and the oxide semiconductor It has the same degree of translucency as

[0133] Therefore, both the oxide semiconductor film 68 and the metal oxide film 70 are formed on the insulating film 66. However, the impurity concentration of the metal oxide film 70 is different from that of the oxide semiconductor film 68. The impurity concentration is high. For example, the hydrogen concentration in the oxide semiconductor film 68 is 5×10 19 a toms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than 1 x10 18 atoms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 Below or less, more preferably 1 × 10 16 atoms / cm 3 The metal oxide film 70 is The hydrogen concentration is 8 x 10 19 atoms / cm 3 or more, preferably 1 × 10 20 a toms / cm 3 More preferably, 5 × 10 20 atoms / cm 3 That's all. In addition, the hydrogen concentration in the metal oxide film 70 is twice as high as that in the oxide semiconductor film 68, which is preferable. Or even 10 times more.

[0134] In addition, an oxide semiconductor film formed at the same time as the oxide semiconductor film 68 is exposed to plasma. This can damage the oxide semiconductor film and form oxygen vacancies. When a film is formed on the oxide semiconductor film by plasma CVD or sputtering, The conductive film is exposed to plasma, and oxygen vacancies are generated. In the etching treatment, the oxide semiconductor film is exposed to plasma, and oxygen vacancies are generated. Alternatively, the oxide semiconductor film is heated in a mixed gas of hydrogen, a rare gas, ammonia, oxygen, and hydrogen. When exposed to plasma such as SiO2, oxygen vacancies are generated. The conductivity increases, the film becomes conductive, and functions as the metal oxide film 70.

[0135] That is, it can be said that the metal oxide film 70 is formed of a highly conductive oxide semiconductor film. It can be said that the metal oxide film 70 is formed of a highly conductive metal oxide film.

[0136] Furthermore, when a silicon nitride film is used as the insulating film 84, the silicon nitride film contains hydrogen. Therefore, hydrogen in the insulating film 84 is transferred to the oxide semiconductor film formed at the same time as the oxide semiconductor film 68. When the hydrogen diffuses, it bonds with oxygen in the oxide semiconductor film, generating electrons as carriers. In addition, when a silicon nitride film is formed by plasma CVD or sputtering, The oxide semiconductor film is exposed to plasma, and oxygen vacancies are generated. When hydrogen contained in the silicon film enters, electrons, which act as carriers, are generated. The oxide semiconductor film becomes highly conductive and turns into a metal oxide film 70 .

[0137] The metal oxide film 70 has a lower resistivity than the oxide semiconductor film 68. Resistivity of the metal oxide film 70 However, the resistivity of the oxide semiconductor film 68 is 1×10 -8 more than 1x10 -1 It is less than double Preferably, typically 1×10 -3 Ωcm or more 1×10 4 less than Ωcm, more preferably , resistivity is 1×10 -3 Ωcm or more 1×10 -1 It is preferable that the resistivity is less than Ωcm.

[0138] However, one aspect of the present invention is not limited to this, and the metal oxide film 70 may be, in some cases, It is also possible that the insulating film 84 is not in contact with the insulating film 84 .

[0139] Furthermore, one aspect of the present invention is not limited to this, and the metal oxide film 70 may be, in some cases, The metal oxide film 70 may be formed in a separate process from the oxide semiconductor film 68. The metal oxide film 70 may have a different material from the oxide semiconductor film 68. For example, Indium tin oxide (hereinafter referred to as ITO) or indium zinc oxide, etc. It may be formed using

[0140] In the display device described in this embodiment, the capacitor element has a light-transmitting property. Since the area occupied by the capacitance element can be made a light transmitting area, the area occupied by the capacitance element can be increased. This allows the aperture ratio of the sub-pixel to be increased while reducing the pixel size.

[0141] The conductive films 72, 74, and 76 are made of conductive materials such as aluminum, titanium, chromium, and nickel. , copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten The metal or alloy containing it as the main component is used as a single layer structure or a laminated structure. For example, a single layer structure of aluminum film containing silicon, a titanium film stacked on an aluminum film, Two-layer structure with a titanium film on a tungsten film, two-layer structure with a copper-magnesium- A two-layer structure in which a copper film is laminated on an aluminum alloy film, a titanium film or titanium nitride film, and An aluminum film or a copper film is laminated on the titanium film or the titanium nitride film, and then the aluminum film or the copper film is laminated on the titanium film or the titanium nitride film. A three-layer structure in which a titanium film or titanium nitride film is formed on top, a molybdenum film or molybdenum nitride film A molybdenum film or molybdenum nitride film is overlaid with an aluminum film or copper film. A three-layer structure is formed by laminating a layer of a molybdenum film or a molybdenum nitride film on top of that. It is also possible to use a transparent conductive material containing indium oxide, tin oxide, or zinc oxide. .

[0142] On the insulating film 66, the oxide semiconductor film 68, the metal oxide film 70, and the conductive films 72, 74, and 76, Insulating films 82 and 84 are formed on the insulating film 82. The insulating film 82, like the insulating film 66, It is preferable to use a material that can improve the interface characteristics with the oxide semiconductor film. In this example, the insulating film 82 is formed of the insulating film 78. , 80 are stacked to form the film.

[0143] The insulating film 78 is an oxide insulating film that transmits oxygen. 3. Mitigating damage to the oxide semiconductor film 68 and the metal oxide film 70 when forming the insulating film 80 It also functions as a Japanese membrane.

[0144] The insulating film 78 has a thickness of 5 nm to 150 nm, preferably 5 nm to 50 nm. The following silicon oxide, silicon oxynitride, etc. can be used. In this regard, a silicon oxynitride film refers to a film whose composition contains more oxygen than nitrogen. The silicon nitride oxide film refers to a film whose composition contains more nitrogen than oxygen. .

[0145] The insulating film 78 is an oxide insulating film, which contains nitrogen and has a low defect amount. It is preferable that the number of

[0146] Typical examples of oxide insulating films that contain nitrogen and have few defects include silicon oxynitride films, Examples include an aluminum oxynitride film.

[0147] The oxide insulating film with few defects shows a high level of The first signal has a g value of 2.037 or more and 2.039 or less, and the second signal has a g value of 2.001 or more and 2. A second signal with a g value of 1.964 or greater and a third signal with a g value of 1.966 or less. The split width of the first signal and the second signal and the The split width of the first signal and the third signal is about 5 m in the X-band ESR measurement. T. The first signal has a g value of 2.037 or more and 2.039 or less, and the second signal has a g value of 2.0 A second signal between 01 and 2.003, and a g value between 1.964 and 1.966, The total spin density of a third signal is 1×10 18 spins / cm 3 is less than , typically 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 less than is.

[0148] In addition, in the ESR spectrum below 100K, the g value is between 2.037 and 2.039. The first signal, the second signal with a g value between 2.001 and 2.003, and the g value between 1. The third signal, between 964 and 1.966, is nitrogen oxides (NOx, where x is between 0 and 2). , preferably 1 or more and 2 or less). Representative examples of nitrogen oxides include: Nitric oxide, nitrogen dioxide, etc. That is, the first group with a g value of 2.037 or more and 2.039 or less signal, a second signal with a g-value between 2.001 and 2.003, and a g-value between 1.96 The smaller the sum of the spin densities of the third signals, which is between 4 and 1.966, the more oxide It can be said that the content of nitrogen oxides contained in the insulating film is low.

[0149] If the insulating film 78 has a low content of nitrogen oxides as described above, the insulating film 78 and the oxide semiconductor It is possible to reduce the number of carrier traps at the interface with the body film. It is possible to reduce the shift in the threshold voltage of the transistor, and the electrical characteristics of the transistor The fluctuations can be reduced.

[0150] The insulating film 78 is also formed by SIMS (Secondary Ion Mass Spectrometry). The nitrogen concentration measured by NMR is 6×10 20 / cm 3 It is preferable that the following As a result, nitrogen oxides are less likely to be generated in the insulating film 78, and the insulating film 78 and the oxides It is possible to reduce carrier traps at the interface with the oxide semiconductor film 68. In addition, it is possible to reduce the shift in the threshold voltage of the transistor. Fluctuations in electrical characteristics can be reduced.

[0151] If the insulating film 78 contains nitrogen oxides and ammonia, the insulating film 78 may be damaged during the manufacturing process. During the heat treatment, nitrogen oxides and ammonia react with each other, and nitrogen oxides become nitrogen gas. As a result, the nitrogen concentration and nitrogen oxide content of the insulating film 78 can be reduced. In addition, carrier transport at the interface between the insulating film 78 and the oxide semiconductor film 68 can be prevented. It is also possible to reduce the shift in the threshold voltage of the transistor. This makes it possible to reduce fluctuations in the electrical characteristics of the transistor.

[0152] In the insulating film 78, all of the oxygen that has entered the insulating film 78 from the outside returns to the outside of the insulating film 78. Some oxygen does not move to the insulating film 78 and remains there. Oxygen contained in the insulating film 78 moves to the outside of the insulating film 78, and oxygen There may also be a movement of

[0153] When an oxide insulating film that transmits oxygen is formed as the insulating film 78, The oxygen desorbed from the insulating film 80 is transferred to the oxide semiconductor film 68 via the insulating film 78. It is possible.

[0154] An insulating film 80 is formed in contact with the insulating film 78. The insulating film 80 has a stoichiometric composition The oxide insulating film is formed using an oxide insulating film containing more oxygen than the oxygen that satisfies the stoichiometric composition. When the oxide insulating film contains more oxygen than the oxygen to be filled, part of the oxygen is released by heating. The oxide insulating film containing more oxygen than the stoichiometric composition is analyzed by TDS. The amount of oxygen released in terms of oxygen atoms is 1.0 × 10 18 atoms / cm 3 That's all, I prefer 3.0 x 10 20 atoms / cm 3 The oxide insulating film is the above-mentioned T The surface temperature of the film during DS analysis is 100°C or higher and 700°C or lower, or 100°C or lower. The temperature is preferably in the range of 500°C or higher.

[0155] The insulating film 80 has a thickness of 30 nm to 500 nm, preferably 50 nm to 40 Silicon oxide, silicon oxynitride, etc., having a thickness of 0 nm or less can be used.

[0156] Furthermore, it is preferable that the insulating film 80 has a small number of defects. Typically, the insulating film 80 has a small number of defects as determined by ESR measurement. The spin density of the signal at g=2.001 originating from the silicon dangling bond is 1 .5×10 18 spins / cm 3 Less than or even 1×10 18 spins / cm 3 Below It is preferable that the insulating film 80 has a thickness smaller than that of the oxide semiconductor film 68 compared to the insulating film 78. Since it is far from the insulating film 78, the defect density may be higher than that of the insulating film 78.

[0157] The insulating film 84 is a material for blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. By providing a nitride insulating film having such an effect, the oxide semiconductor film 68 and the metal oxide film 70 The nitride insulating film can prevent oxygen from diffusing to the outside. Examples include silicon nitride oxide, aluminum nitride, and aluminum nitride oxide.

[0158] In addition, it has a blocking effect against oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. An oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like is provided over the nitride insulating film. As the oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like, aluminum oxide Aluminum, aluminum oxide nitride, gallium oxide, gallium oxide nitride, yttrium oxide , yttrium oxide nitride, hafnium oxide, hafnium oxide nitride, etc. To control the capacitance of the element, oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. A nitride insulating film or an oxide insulating film may be appropriately provided on the nitride insulating film having a blocking effect. stomach.

[0159] In addition, a conductive film 86 is formed on the insulating film 84. The conductive film 86 is a film for forming pixel electrodes and The conductive film 86 functions as an electrode of the capacitor element. The conductive film 74 is connected to the conductive film 74 .

[0160] The conductive film 86 can be formed using a light-transmitting conductive material. , indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide oxide, indium oxide with titanium oxide, indium tin oxide with titanium oxide, IT Indium tin oxide with added silicon dioxide, indium zinc oxide, and the like can be used. can.

[0161] An alignment film 88 is formed on the insulating film 84 and the conductive film 86. It is desirable for the material to be light-transmitting, and typical examples include acrylic resin, polyimide, and epoxy. Organic resins such as silicon resins can be used.

[0162] The above is a description of each member on the substrate 60 that serves as the element substrate.

[0163] Next, each member on the substrate 90 that serves as the opposing substrate will be described.

[0164] A light-shielding film BM is provided on the substrate 90, and openings 55B, 55G, Color filters 53B and 53G and a light-transmitting layer 53W are formed on the substrate 55W. do.

[0165] The color filter 53R (53G, 53B) is a color filter that transmits light in a specific wavelength range. Any filter is sufficient, for example, a color filter that transmits light in the red wavelength band, a green color filters that transmit light in the blue wavelength band, and color filters that transmit light in the red wavelength band. A printer or the like can be used.

[0166] The light-shielding film BM may be any film having a function of blocking light in a specific wavelength range, such as a metal film, Alternatively, an organic insulating film containing a black pigment or the like can be used.

[0167] The light-transmitting layer 53W is preferably light-transmitting, and is typically made of an acrylic resin. For example, organic resins such as polyimide and epoxy resins can be used. Alternatively, the insulating layer 12 may be formed by stacking a conductive material having light-transmitting properties and an organic resin. The organic resin may contain a metal element. As the layer having the layer 53W, a layer that absorbs light of a specific wavelength may be provided. In this configuration, even if an appropriate white color is not obtained depending on the wavelength of the light from the light source, the white Since the balance can be adjusted, a display with high color purity can be achieved.

[0168] Further, on the color filters 53R, 53B, 53G and the light-transmitting layer 53W, an insulating layer The insulating film 92 functions as a flattening layer or a color filter. The impurities that may be contained in the layers 53R, 53B, 53G, and the light-transmitting layer 53W are removed by the liquid crystal element. The color filters 53R, 53B, and 53C have the function of suppressing the diffusion of light toward the 53R, 53B, and 53C side. It is preferable that the light-transmitting layer 3G and the light-transmitting layer 53W do not overlap each other on the light-shielding film BM. With this structure, the flatness of the surface of the conductive film 94 can be improved.

[0169] Furthermore, a conductive film 94 is formed on the insulating film 92. The conductive film 94 is a film for connecting the liquid crystal elements of the pixel portion. The conductive film 94 functions as the other of the pair of electrodes of the element. It can be made of the same material.

[0170] An alignment film 96 is formed on the conductive film 94. The alignment film 96 has the same structure as the alignment film 88. It can be made of a material.

[0171] A liquid crystal layer 95 is formed between the conductive film 86 and the conductive film 94. 5 is sealed between the substrate 60 and the substrate 90 using a sealing material (not shown). The sealing material is made of a material that comes into contact with inorganic materials to prevent moisture from entering from the outside. Composition is preferred.

[0172] In addition, the thickness of the liquid crystal layer 95 (also called a cell gap) is maintained between the conductive film 86 and the conductive film 94. A spacer may be provided to support the

[0173] The above is a description of each member on the substrate 90 that serves as the opposing substrate.

[0174] As described above, the semiconductor film of the transistor included in each subpixel is an oxide semiconductor film, and the capacitance element In this structure, the electrode constituting the capacitor element is formed of a light-transmitting conductive film. Because it is transparent, the area occupied by the capacitive element in the subpixel appears smaller. When a pixel is composed of RGBW sub-pixels, the area per sub-pixel becomes smaller, but the transparency Because the capacitance element has optical properties, the aperture ratio does not decrease even if the area occupied by the capacitance element is large. Therefore, it is possible to increase the capacitance while increasing the aperture ratio. As a result, the display device can achieve a reduction in power consumption. can.

[0175] The light-transmitting conductive film constituting the capacitor element is provided in the same layer as the semiconductor film of the transistor. Since it is formed from a metal oxide film, it can be formed using materials that can be used without increasing the number of processes. It can be made.

[0176] <Modifications of Color Filters of Subpixels> 6 and 7 described above show a configuration in which the light-transmitting layer 53W is provided. However, as shown in FIG. 8(A), a configuration in which the light-transmitting layer 53W is not provided may be used. In this case, the cross-sectional structure is as shown in FIG. 8(A) taken as an example of the cross section between the chain lines EF. With this configuration, the portion that becomes the light-transmitting layer 53W can be expressed as shown in (B). This can reduce the amount of material used and also the number of steps for forming the light-transmitting layer 53W.

[0177] 6 and 7, the color filters 53R, 53B, and 53G and the transparent Although the configuration in which the layers 53W having the optical properties do not overlap each other on the light-shielding film BM has been shown, the present invention is not limited to this. Instead, they may be overlapped as shown in Fig. 9(A). In this case, the cross-sectional structure of Fig. 9(A) Taking the cross section between the chain lines G and H as an example, it can be expressed as shown in FIG. Thus, color filters 53R, 53B, and 53G and a light-transmitting layer 53W are formed. This can suppress light leakage due to mask misalignment when the mask is inserted.

[0178] 9A and 9B, color filters 53R, 53B, and 53G and a transparent substrate 53A are provided. 1 shows a configuration in which the layers 53W overlap each other on the light-shielding film BM. As shown in Fig. 0(A), it is also possible to have a configuration in which some parts overlap and some parts do not. The surface structure is shown in Fig. 9(B) for the cross section between the chain lines GH and IJ in Fig. 10(A). ), can be expressed as shown in FIG. 10(B). With this configuration, the color filter 53R , 53B, 53G, and the light-transmitting layer 53W. can be suppressed.

[0179] 6 and 7, the color filters 53R, 53B, and 53G and the transparent Although the layer 53W having the property is provided separately in each sub-pixel in the above example, the present invention is not limited to this. First, as shown in FIG. 11(A), even if a light-transmitting layer 53W is superimposed on the entire surface inside the pixel 13, In this case, the cross-sectional structure is as shown in FIG. 11(A) taken as an example of the cross section between the chain lines KL. This can be expressed as shown in Figure 1(B). By using this configuration, the number of masks can be reduced. This can be done.

[0180] <Method for manufacturing transistors and capacitors on the element substrate> Next, we will explain how to fabricate each member on the element substrate side. The method of manufacturing each member provided on the plate 60 will be described with reference to FIGS. The members provided on the substrate 60, which is the element substrate, are sandwiched between the substrate 60 and the alignment film 88. In the following, we will focus on the manufacturing method of the components on the element substrate side. Regarding this, using the cross-sectional structure taken along the chain lines AB and CD in FIG. 5(A) shown in FIG. 7, explain.

[0181] The films that make up a transistor (insulating film, oxide semiconductor film, metal oxide film, conductive film, etc.) are Sputtering, Chemical Vapor Deposition (CVD), Vacuum Evaporation, Pulsed Laser Deposition (PLD) Alternatively, it can be formed by a coating method or a printing method. The typical film formation methods are sputtering and plasma enhanced chemical vapor deposition (PECVD). However, thermal CVD may also be used. An example of a thermal CVD method is MOCVD (metal organic chemical vapor deposition). Alternatively, a deposition (multilayer deposition) method or an atomic layer deposition (ALD) method may be used.

[0182] In the thermal CVD method, the chamber is kept at atmospheric pressure or reduced pressure, and the source gas and oxidant are simultaneously mixed in the chamber. The film is formed by sending the gas into the chamber, reacting it near or on the substrate, and depositing it on the substrate. As described above, the thermal CVD method is a film formation method that does not generate plasma. This has the advantage that defects are not generated due to damage.

[0183] In the ALD method, the chamber is kept at atmospheric pressure or reduced pressure, and the source gases for the reaction are sequentially introduced. Next, the gas is introduced into the chamber, and the film is formed by repeating this gas introduction sequence. By switching each switching valve (also called high-speed valve), two or more types of raw material gas can be The first and second source gases are supplied to the chamber in order to prevent the multiple source gases from mixing. At the same time or afterwards, an inert gas (argon, nitrogen, etc.) is introduced to If an inert gas is introduced at the same time, the inert gas is introduced as a carrier gas. In addition, an inert gas may be introduced at the same time as the second source gas is introduced. Instead of introducing an inert gas, the first source gas is discharged by evacuation, and then the second source gas is introduced. A source gas may be introduced. The first source gas is adsorbed on the surface of the substrate to form a first monoatomic layer. The second monolayer is formed on the first monolayer by reacting with the second source gas introduced later. The thin film is formed by stacking the layers.

[0184] By controlling the gas introduction order and repeating this process multiple times until the desired thickness is achieved, the step coverage is improved. The thickness of the thin film can be increased by repeating the gas introduction sequence. This allows precise film thickness control, making it possible to fabricate minute transistors. It is suitable for manufacturing.

[0185] First, prepare the substrate 60. Here, a glass substrate is used as the substrate 60.

[0186] Next, a conductive film is formed on the substrate 60 (see FIG. 12(A)), and the conductive film is applied to a desired region. The conductive film 62 is formed by applying the first pattern to a desired region. forming a mask by etching and then etching the areas not covered by the mask; (See FIG. 12(B)).

[0187] The conductive film 62 is typically formed by a sputtering method, a vacuum deposition method, a PLD method, or a thermal CVD method. It can be formed by using a method such as the above.

[0188] In addition, a tungsten film is formed as the conductive film 62 by a film forming apparatus using ALD. In this case, WF6 gas and B2H6 gas are introduced repeatedly in order to obtain the initial tongue. After that, WF6 gas and H2 gas are introduced simultaneously to form a tungsten film. It should be noted that SiH4 gas may be used instead of B2H6 gas.

[0189] Next, an insulating film 64 is formed on the substrate 60 and the conductive film 62, and an insulating film 66 is formed on the insulating film 64. (See FIG. 12(C)).

[0190] The insulating film 64 and the insulating film 66 can be formed by a sputtering method, a CVD method, a vacuum deposition method, a PLD method, a thermal The insulating film 64 and the insulating film 66 can be formed by a CVD method or the like. Continuous formation is preferable because it prevents the inclusion of impurities.

[0191] When a silicon oxide film or a silicon oxynitride film is formed as the insulating film 64 and the insulating film 66, In this case, it is preferable to use a deposition gas containing silicon and an oxidizing gas as the source gas. Typical examples of silicon-containing deposition gases are silane, disilane, trisilane, and fluorine. Oxidizing gases include oxygen, ozone, nitrous oxide, and nitrogen dioxide. be.

[0192] When forming gallium oxide films as the insulating films 64 and 66, the MOCVD method is used. It can be formed using

[0193] The insulating film 64 and the insulating film 66 are formed by using a thermal CVD method such as an MOCVD method or an ALD method. In the case of forming a hafnium oxide film, a liquid containing a solvent and a hafnium precursor compound is used. (Hafnium alkoxide solution, typically tetrakisdimethylamidohafnium (TD Two types of gases are used: vaporized raw material gas (MAH) and ozone (O3) as an oxidizing agent. The chemical formula for tetrakisdimethylamidohafnium is Hf[N(CH3)2]4. Other liquid materials include tetrakis(ethylmethylamido)hafnium. be.

[0194] The insulating film 64 and the insulating film 66 are formed by using a thermal CVD method such as an MOCVD method or an ALD method. In the case of forming an aluminum oxide film, a solvent and an aluminum precursor compound are used. The raw material gas is a vaporized liquid (such as trimethylaluminum TMA) and H2 as an oxidizer. Two types of gases are used: O and Al(CH3). The chemical formula for trimethylaluminum is Al(CH3)3. Other liquid materials include tris(dimethylamido)aluminum and triisopropyl alcohol. Butyl aluminum, aluminum tris(2,2,6,6-tetramethyl-3,5-hexyl) butanedionate), etc.

[0195] The insulating film 64 and the insulating film 66 are formed by using a thermal CVD method such as an MOCVD method or an ALD method. When forming a silicon oxide film, hexachlorodisilane is adsorbed on the surface to be formed. Removes chlorine contained in the adsorbed material and supplies radicals of oxidizing gases (O2, nitrous oxide) and reacts with the adsorbate.

[0196] Next, an oxide semiconductor film 67 is formed over the insulating film 66 (see FIG. 12C).

[0197] The oxide semiconductor film 67 can be formed by a sputtering method, a coating method, a pulsed laser deposition method, a laser ablation method, or the like. The film can be formed by abrasion, thermal CVD, or the like.

[0198] The sputtering gas is a rare gas (typically argon), oxygen, or a mixture of rare gas and oxygen. In the case of a mixture of rare gas and oxygen, the gas ratio of oxygen to rare gas is It is preferable to increase

[0199] The target may be appropriately selected depending on the composition of the oxide semiconductor film to be formed.

[0200] Note that when the oxide semiconductor film is formed by, for example, a sputtering method, the substrate temperature The temperature is 150°C or higher and 750°C or lower, preferably 150°C or higher and 450°C or lower, and more preferably The oxide semiconductor film is formed at a temperature of 200°C or higher and 350°C or lower. A film can be formed.

[0201] In addition, the following conditions are preferably applied to form the CAAC-OS film.

[0202] By suppressing the inclusion of impurities during film formation, it is possible to prevent the crystal state from being destroyed by impurities. For example, the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be reduced. In addition, the impurity concentration in the deposition gas can be reduced. A deposition gas having a temperature of 80° C. or less, preferably −100° C. or less, is used.

[0203] Oxide semiconductor films, such as InGaZnO, are formed using a deposition system that uses ALD. X (X>0) membrane When forming a film, In(CH3)3 gas and O3 gas are introduced in sequence repeatedly to form InO2 Then, Ga(CH3)3 gas and O3 gas are introduced simultaneously to form a GaO layer. Then, Zn(CH3)2 gas and O3 gas are introduced simultaneously to form a ZnO layer. The order of these layers is not limited to this example. layer, and mixed compound layers such as InZnO2 layer, GaInO layer, ZnInO layer, and GaZnO layer It is also possible to form a H2O gas bubbled with an inert gas such as Ar instead of O3 gas. However, it is preferable to use O3 gas that does not contain H. In(CH3 In place of In(C2H5)3 gas, Ga(CH3)3 gas may be used. Instead of gas, Ga(C2H5)3 gas may be used. It's fine.

[0204] Next, the oxide semiconductor film 67 is processed into desired regions to form island-shaped oxide semiconductor films 68, The oxide semiconductor films 68 and 69 are formed in desired regions by a second patterning process. and etching the area not covered by the mask. Etching can be performed by dry etching, wet etching, or Alternatively, etching using a combination of both methods can be used (see FIG. 12(D)).

[0205] After that, heat treatment is performed to remove hydrogen, water, and the like from the oxide semiconductor films 68 and 69. By separating the oxide semiconductor films 68 and 69, the hydrogen concentration and the water concentration in the oxide semiconductor films 68 and 69 may be reduced. As a result, highly purified oxide semiconductor films 68 and 69 can be formed. The temperature is typically 250°C or higher and 650°C or lower, preferably 300°C or higher and 500°C or lower. The temperature of the heat treatment is typically 300°C or higher and 400°C or lower, preferably By keeping the temperature between 320℃ and 370℃, warping and shrinkage of the substrate can be prevented even in large area substrates. This allows for a reduction in ink consumption and improves yield.

[0206] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, heat treatment can be performed at a temperature above the strain point of the substrate for a short period of time. It is possible to shorten the processing time and reduce the warping of the substrate during the heat treatment. This is particularly preferable for large area substrates.

[0207] The heat treatment is carried out in nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably air at 1 ppm or less, preferably 10 ppb or less), or rare gases (argon, helium The above-mentioned nitrogen, oxygen, ultra-dry air, or rare gas may be added to hydrogen. It is preferable that the mixture does not contain water or the like. After the heat treatment in a nitrogen or rare gas atmosphere, Heating may be performed in an oxygen or ultra-dry air atmosphere. Hydrogen, water, and the like can be desorbed and oxygen can be supplied to the oxide semiconductor film. As a result, the amount of oxygen vacancies in the oxide semiconductor film can be reduced.

[0208] When the temperature for forming the insulating film 77 to be formed later is set to 280° C. or more and 400° C. or less, Since it is possible to desorb hydrogen, water, etc. contained in the compound semiconductor films 68 and 69, No heat treatment is required.

[0209] Next, a conductive film 71 is formed on the insulating film 66 and the oxide semiconductor films 68 and 69 (FIG. 13( See A). ).

[0210] The conductive film 71 is formed by a sputtering method, a vacuum deposition method, a PLD method, a thermal CVD method, or the like. It is possible.

[0211] Next, the conductive film 71 is processed into desired regions to form conductive films 72, 74, and . The conductive films 72, 74, and 76 are patterned in desired areas to form a mask by a third patterning. and then etching the areas not covered by the mask. (See Figure 13(B)).

[0212] Next, a thin film is formed on the insulating film 66, the oxide semiconductor films 68 and 69, and the conductive films 72, 74, and 76 so as to cover the insulating film 66, the oxide semiconductor films 68 and 69, and the conductive films 72, 74, and 76. As shown, the insulating films 77 and 79 are stacked to form an insulating film 81 (see FIG. 13(C)). The insulating film 81 can be formed by using a sputtering method, a CVD method, a vapor deposition method, or the like.

[0213] After the insulating film 77 is formed, the insulating film 79 is successively formed without exposing it to the air. After the insulating film 77 is formed, the flow rate, pressure, and high frequency of the source gas are adjusted without exposing the insulating film 77 to the atmosphere. By adjusting one or more of the power and the substrate temperature, the insulating film 79 is continuously formed. 7, 79 can reduce the concentration of impurities derived from atmospheric components at the interface, and Oxygen contained in the film 79 can be transferred to the oxide semiconductor films 68 and 69, and the oxide The amount of oxygen vacancies in the compound semiconductor films 68 and 69 can be reduced.

[0214] For the insulating film 77, the oxidizing gas is more than 20 times but less than 100 times the deposition gas; Preferably, the pressure in the processing chamber is set to 40 or more and 80 or less, and the pressure in the processing chamber is set to less than 100 Pa, preferably 50 Pa By using a CVD method with a thickness of 0.1 or less, an oxide insulating film containing nitrogen and with few defects can be formed. It can be formed.

[0215] As the source gas of the insulating film 77, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of silicon-containing deposition gases include silane, disilane, trisilane, and the like. Oxidizing gases include oxygen, ozone, nitrous oxide, and fluorinated silane. Nitrogen, etc.

[0216] By using the above conditions, an oxide insulating film that transmits oxygen can be formed as the insulating film 77. Furthermore, by providing the insulating film 77, in the process of forming the insulating film 79 to be formed later, As a result, damage to the oxide semiconductor films 68 and 69 can be reduced.

[0217] The insulating film 79 is formed by depositing a substrate placed in a vacuum-evacuated processing chamber of a plasma CVD apparatus. The temperature is maintained at 180°C or higher and 280°C or lower, more preferably 200°C or higher and 240°C or lower. The raw material gas is introduced into the chamber to set the pressure in the processing chamber to 100 Pa or more and 250 Pa or less, and Preferably, the pressure is 100 Pa or more and 200 Pa or less, and 0.17 W is applied to the electrodes provided in the processing chamber. / cm 2 More than 0.5W / cm 2 or less, more preferably 0.25 W / cm 2 Over 0.35 W / cm 2Under the following conditions for supplying high frequency power, silicon oxide film or silicon oxynitride film is formed. Form a con film.

[0218] As the source gas of the insulating film 79, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of silicon-containing deposition gases include silane, disilane, trisilane, and the like. Oxidizing gases include oxygen, ozone, nitrous oxide, and fluorinated silane. Nitrogen, etc.

[0219] As a film forming condition for the insulating film 79, high frequency power is supplied to separate the raw material gas in the plasma. The decomposition efficiency increases, oxygen radicals increase, and oxidation of the source gas progresses. However, the oxygen content in the insulating film 7 becomes higher than the stoichiometric ratio. At the film formation temperature of 9, the bond between silicon and oxygen is weak, so some of the oxygen is released by heating. As a result, the oxygen content is greater than the stoichiometric value, and the oxygen content is increased by heating. In addition, the oxide insulating film 68, An insulating film 77 is provided on the insulating film 69. The film 77 serves as a protective film for the oxide semiconductor films 68 and 69. The insulating film 79 is formed using high-frequency power with high power density while reducing damage to the insulating film 79. It is possible.

[0220] In the film forming conditions for the insulating film 79, the ratio of the deposition gas containing silicon to the oxidizing gas is By increasing the flow rate, it is possible to reduce the number of defects in the insulating film 79. ESR measurements revealed a signal at g = 2.001 originating from silicon dangling bonds. The spin density of the number is 6×1017 spins / cm 3 Less than 3 x 10 17 spi ns / cm 3 Less than or equal to 1.5 × 10 17 spins / cm 3 of defects is less than or equal to As a result, the reliability of the transistor can be improved. This can be done.

[0221] Next, a heat treatment is performed. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate distortion point. Preferably, the temperature is 200°C or higher and 450°C or lower, and more preferably, 300°C or higher and 450°C or lower. The temperature of the heat treatment is typically 300°C or higher and 400°C or lower, preferably 3 By keeping the temperature between 20℃ and 370℃, warping and shrinkage of the substrate can be prevented even in large area substrates. This allows for a reduction in the number of defects, thereby improving yield.

[0222] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, the heat treatment can be performed at a temperature above the distortion point of the substrate for a short period of time. This can reduce processing time.

[0223] Heat treatment is carried out in nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably 1 ppm). m or less, preferably 10 ppb or less of air), or rare gases (argon, helium, etc.) The reaction may be carried out under an atmosphere of nitrogen, oxygen, ultra-dry air, or a rare gas, hydrogen, water, etc. It is preferable that it does not contain

[0224] By this heat treatment, part of oxygen contained in the insulating film 79 is transferred to the oxide semiconductor films 68 and 69. By this, oxygen vacancies in the oxide semiconductor films 68 and 69 can be reduced. As a result, the amount of oxygen vacancies in the oxide semiconductor films 68 and 69 can be further reduced. .

[0225] In addition, when the insulating films 77 and 79 contain water, hydrogen, etc., the insulating films 77 and 79 have a function of blocking water, hydrogen, etc. When the insulating film 83 having the above structure is formed later and subjected to heat treatment, the water contained in the insulating films 77 and 79 Hydrogen and the like move to the oxide semiconductor films 68 and 69, causing defects in the oxide semiconductor films 68 and 69. However, the heating removes water, hydrogen, etc. contained in the insulating films 77 and 79. This reduces the variation in the electrical characteristics of the transistors and also This makes it possible to suppress fluctuations in the low voltage.

[0226] Note that by forming the insulating film 79 over the insulating film 77 while heating, the oxide semiconductor film 68 Oxygen is transferred to the oxide semiconductor films 68 and 69, and oxygen vacancies in the oxide semiconductor films 68 and 69 are reduced. Therefore, the heat treatment may not be performed.

[0227] Furthermore, when the conductive films 72, 74, and 76 are formed, the oxide semiconductor is removed by etching the conductive films. The oxide semiconductor films 68 and 69 are damaged, and the back channel (oxide semiconductor In the film 68, the surface opposite to the surface facing the conductive film 62 functioning as the gate electrode is However, the insulating film 79 contains more oxygen than the oxygen required for the stoichiometric composition. By using an oxide insulating film containing Oxygen vacancies can be repaired. This reduces the number of defects in the oxide semiconductor film 68. Since the resistance can be reduced, the reliability of the transistor can be improved.

[0228] The heat treatment may be performed after the opening 50GW, which will be formed later, is formed.

[0229] Next, the insulating films 77 and 79 are processed into desired regions, and the insulating films 78 and 80 are stacked. The insulating film 82 and the opening 5GW are formed. 0GW forms a mask by fourth patterning in a desired area, and the mask is covered It can be formed by etching the unprotected area (see FIG. 14(A)). .

[0230] The opening 50GW is formed so that the surface of the oxide semiconductor film 69 is exposed. The 50 GW can be formed by, for example, dry etching. It is preferable to etch the insulating film 81 by a dipping etching method. Since the semiconductor film 69 is exposed to plasma in the etching treatment, the oxide semiconductor film 69 It is possible to increase the oxygen vacancy. However, as a method for forming the opening 50GW, Not limited to this, wet etching method, or dry etching method and wet etching method may be used. A combination of these methods may also be used.

[0231] Next, the insulating film 83 is formed over the insulating film 82 and the oxide semiconductor film 69 (see FIG. 14B). .).

[0232] The insulating film 83 is formed by removing impurities from the outside, such as oxygen, hydrogen, water, alkali metals, and aluminum. It is preferable to use a material that prevents potassium earth metals and the like from diffusing into the oxide semiconductor film. Preferably, the insulating material contains hydrogen, and is typically an inorganic insulating material containing nitrogen, such as a nitride insulating material. The insulating film 83 can be formed by, for example, a CVD method or a sputtering method. It can be formed using

[0233] When the insulating film 83 is formed by plasma CVD or sputtering, an oxide semiconductor film is formed. The insulating film 83 is exposed to plasma, and oxygen vacancies are generated in the oxide semiconductor film. Impurities from the oxide semiconductor film, such as water, alkali metals, and alkaline earth metals, diffuse into the oxide semiconductor film. The insulating film 83 is made of a material that prevents hydrogen from diffusing into the atmosphere. When hydrogen diffuses into the oxide semiconductor film 69, the hydrogen bonds with oxygen in the oxide semiconductor film 69. When the oxygen atoms combine with the oxide semiconductor film, electrons serving as carriers are generated. The hydrogen atoms enter the oxide semiconductor film 6, generating electrons as carriers. 9 becomes highly conductive and becomes a metal oxide film 70.

[0234] In addition, the silicon nitride film is preferably formed at a high temperature in order to enhance blocking properties. For example, the substrate temperature is 100°C or higher and 400°C or lower, more preferably 300°C or higher and 400°C or lower. It is preferable to form the film by heating at the following temperature. Oxygen is released from the oxide semiconductor used as the dielectric film 68, and the carrier concentration increases. Therefore, the temperature must be set at a level at which this phenomenon does not occur.

[0235] Next, the insulating films 82 and 83 are processed into desired regions, so that the insulating films 82, 84, and The insulating film 84 and the opening 47B are formed in a desired region. A mask is formed by patterning, and the area not covered by the mask is etched. By doing so, it can be formed (see FIG. 14(C)).

[0236] Next, a conductive film 85 is formed (see FIG. 15(A)).

[0237] The conductive film 85 can be formed using a light-transmitting conductive material. , indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide oxide, indium oxide with titanium oxide, indium tin oxide with titanium oxide, IT Indium tin oxide with added silicon dioxide, indium zinc oxide, and the like can be used. The conductive film 85 can be formed by using, for example, a sputtering method.

[0238] Next, the conductive film 85 is processed into a desired region to form a conductive film 86. 86 is a sixth patterning process for forming a mask in a desired area, and the mask is then formed. It can be formed by etching the unfilled area (see FIG. 15(B)).

[0239] Next, an alignment film 88 is formed (see FIG. 15(C)).

[0240] The alignment film 88 can be formed using a rubbing method, a photoalignment method, or the like.

[0241] Through the above steps, a transistor and a capacitor can be manufactured.

[0242] As an example, an element substrate of a liquid crystal display device according to one embodiment of the present invention is Since the pixel electrodes are formed at the same time as the nitride semiconductor film, six photomasks are used to The pixel electrode is used as one electrode of the capacitor element. Therefore, a new process of forming a conductive film is not required to form a capacitor element. Therefore, the manufacturing process can be reduced. In addition, the capacitor element has a light-transmitting property. It is possible to increase the aperture ratio of the pixel while increasing the area occupied by the pixel.

[0243] <Method for manufacturing the light-shielding film and color filter on the opposing substrate> Next, we will explain how to fabricate each member on the opposing substrate side. Regarding the method of manufacturing the light-shielding film and color filters provided on the plate 90, please refer to FIGS. 16 and 17. The following description will be given using the substrate 90 as a counter substrate. and the alignment film 96. In the following, the term "opposite substrate" refers to the components in the area sandwiched between the alignment film 96 and the alignment film 96. Regarding the manufacturing method of the member, the cross-sectional structure along the chain lines AB and CD in Figure 6 is shown in Figure 7. We will explain using this structure.

[0244] First, a substrate 90 is prepared. The materials shown for the substrate 60 can be used for the substrate 90. Next, a light-shielding film BM is formed on the substrate 90 (see FIG. 16(A)).

[0245] The light-shielding film BM is made of a metal film or an organic insulating film containing black pigments, etc., and is printed using a printing method or ink. Jet method, etching method using photolithography technology, etc. Form into.

[0246] Next, openings 55B and 55W are formed on the light-shielding film BM, and color filters are formed in the openings 55G and 55B. Filters 53G and 53B are formed (see FIG. 16(B)). A color filter 53R is formed on the substrate 55R.

[0247] Next, a light-transmitting layer 53W is formed in the opening 55W (see FIG. 16(C)). The layer 53W having the adhesive property can be made of, for example, an acrylic resin.

[0248] Next, an insulating film 92 is formed on the light-shielding film BM and the color filters 53G and 53B (FIG. 17 See (A). ).

[0249] The insulating film 92 is made of an organic insulating film such as acrylic resin, epoxy resin, or polyimide. By forming the insulating film 92, for example, the color filter 5 It is possible to prevent impurities contained in 3G and 53B from diffusing to the liquid crystal layer 95 side. However, the insulating film 92 does not necessarily have to be provided.

[0250] Next, a conductive film 94 is formed on the insulating film 92, and an alignment film 96 is formed on the conductive film 94 (FIG. 17(B)). (See FIG. 1.) The conductive film 94 may be made of the same material as the conductive film 86.

[0251] The alignment film 96 can be formed by using a rubbing method, a photoalignment method, or the like.

[0252] Through the above steps, the structure formed on the substrate 90 can be formed.

[0253] Thereafter, a liquid crystal layer 95 is formed between the substrate 60 and the substrate 90. For example, a dispenser method (dropping method) or a method of bonding the substrate 60 and the substrate 90 together and then applying a capillary A liquid crystal injection method using the phenomenon can be used.

[0254] Through the above steps, the liquid crystal display device shown in FIG. 7 can be manufactured.

[0255] According to one aspect of the present invention described above, (1) the area of the opening of the W sub-pixel is (2) to reduce the number of wirings that control the pixels; (3) the sub-pixels are arranged in a 2-row, 2-column configuration; The capacitor element has a conductive film having a light-transmitting property, and the capacitor element has an oxide semiconductor film as a main film. Therefore, the present invention is characterized by at least one of the following: (1) reducing saturation; (2) the number of wirings required to drive the four sub-pixels can be reduced. (3) It is possible to increase the aperture ratio and the number of processes without reducing the required capacitance value. As a result, the display device can reduce power consumption. It is possible to reduce this.

[0256] <About oxide conductors (metal oxide films)> Here, a film formed of an oxide semiconductor (hereinafter referred to as an oxide semiconductor film (OS)) and an oxide semiconductor film (OS) are In each of the films formed by oxide conductors (hereinafter referred to as oxide conductor films (OC)), The temperature dependence of resistivity will be explained using FIG. 34. In FIG. 34, the horizontal axis represents the measured The vertical axis shows the temperature, and the vertical axis shows the resistivity. The measurement results of the oxide semiconductor film (OS) are shown by circles. The measurement results for the oxide conductor film (OC) are indicated by square marks.

[0257] The sample including the oxide semiconductor film (OS) was prepared by depositing an oxide semiconductor film having an atomic ratio of In:Ga: The thickness was determined by sputtering using a sputtering target of Zn=1:1:1.2. A 35 nm In-Ga-Zn oxide film was formed with an atomic ratio of In:Ga:Zn=1:4: 5 sputtering target was used to deposit a 20 nm thick In-G After forming a α-Zn oxide film and heat-treating it in a nitrogen atmosphere at 450°C, The silicon nitride film is then formed by plasma CVD. Formed and produced.

[0258] The sample containing the oxide conductor (OC) film was prepared by depositing an oxide film with an atomic ratio of In:Ga: A 10 mm thick film was deposited by sputtering using a Zn=1:1:1 sputtering target. After forming a 0 nm In-Ga-Zn oxide film and heat-treating it in a nitrogen atmosphere at 450°C, Heat treatment was carried out in a mixed gas atmosphere of nitrogen and oxygen at 450°C, and silicon nitride was formed by plasma CVD. It was fabricated by forming a silicon film.

[0259] As can be seen from FIG. 34, the temperature dependence of resistivity in the oxide conductor film (OC) is The temperature dependence of resistivity is smaller than that of the oxide semiconductor film (OS). The change rate of the resistivity of the oxide semiconductor film (OC) at 90K or less is less than ±20%. Alternatively, the rate of change in resistivity between 150K and 250K is less than ±10%. That is, an oxide conductor is a degenerate semiconductor, and the conduction band edge and the Fermi level coincide or almost coincide. Therefore, when oxide conductor films are used for wiring, electrodes, pixel electrodes, etc. It is possible.

[0260] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0261] (Embodiment 2) In this embodiment, the portions formed on the element substrate and / or the counter substrate described in the first embodiment are Modified examples of the material will be described with reference to FIGS.

[0262] <Variation 1> The transistor 21B (21R, 21B or 18, an insulating layer is provided at a position overlapping with the oxide semiconductor film 68. A configuration in which an insulating film 98 is provided may also be used.

[0263] The insulating film 98 preferably has a thickness of 500 nm or more and 10 μm or less.

[0264] The insulating film 98 is made of an organic resin such as an acrylic resin, a polyimide resin, or an epoxy resin. The insulating film 98 made of organic resin is sometimes called an organic insulating film.

[0265] The transistor 21B (21R, 21B or 21W) shown in FIG. The insulating film 98 has a thickness of 500 nm or more, so it can be used as a gate electrode. The influence of the electric field generated by applying a negative voltage to the conductive film 62 that functions as a 98, and the surface of the insulating film 98 is unlikely to be positively charged. Even if the positively charged particles contained in the insulating film 98 are adsorbed on the surface of the insulating film 98, the insulating film 98 is Since the thickness is as large as above, the electric field of the positively charged particles adsorbed on the surface of the insulating film 98 is As a result, the interface between the oxide semiconductor film 68 and the insulating film 84 is hardly affected. At the interface of the insulating film 84, a state in which a positive bias is substantially not applied is created, and the transistor The fluctuation of the threshold voltage of the capacitor is small.

[0266] From the above, by providing the isolated insulating film 98 on the transistor, the transistor It is possible to reduce the variation in the electrical characteristics of the device. A highly reliable transistor can be manufactured. Since the formation can be performed by a method such as a method for forming the insulating film, the manufacturing time can be shortened.

[0267] Although not shown, the transistors 21R, 21B, and 21W are also shown in FIG. In the same manner as above, the insulating film 98 can be formed.

[0268] 19, the alignment film 88 on the insulating film 98 and the element layer 99 on the substrate 90 are In this case, the insulating film 98 may be in contact with the alignment film 96 included in the spacer. Since the insulating film 98 functions as a spacer, the cell gap of the liquid crystal display device can be maintained by the insulating film 98. do.

[0269] <Variation 2> As a modification of the oxide semiconductor films 68 and 69 shown in FIG. 12(D) of the first embodiment, As shown in A) and B, the oxide semiconductor film can have a stacked structure.

[0270] In the transistor shown in FIG. 20A, the oxide semiconductor film 68 is formed of oxide semiconductor films 68A and 68 The oxide semiconductor film 69 is formed of oxide semiconductor films 69A and 69B.

[0271] The oxide semiconductor films 68B and 69B are made of one of the elements constituting the oxide semiconductor films 68A and 69A. The oxide semiconductor films 68B and 69B are formed by the oxide semiconductor films 68A and 69A. Since the oxide semiconductor films 68A and 69A are made of one or more elements constituting the oxide semiconductor film, At the interfaces with the semiconductor films 68B and 69B, interfacial scattering is unlikely to occur. Since the movement of carriers is not hindered in the .

[0272] For example, the oxide semiconductor films 68A and 69A may be made of In:Ga:Zn=1:1:1, In:G In-Ga-Zn oxide with an atomic ratio of a:Zn=1:1:1.2 or 3:1:2 was used. The oxide semiconductor films 68B and 69B may be formed of In:Ga:Zn=1: 3:n (n is an integer between 2 and 8, inclusive), 1:6:m (m is an integer between 2 and 10, inclusive), or An In-Ga-Zn oxide with an atomic ratio of 1:9:6 can be used.

[0273] The oxide semiconductor films 68B and 69B are formed by using oxide semiconductors when forming the insulating film 80 to be formed later. It also functions as a film for reducing damage to the conductive films 68A and 6A.

[0274] In FIG. 20A, the oxide semiconductor films 68A and 69A and the oxide semiconductor film 68B 20B, the oxide semiconductor films 68C and 69C are formed as a two-layer structure. It may have a three-layer structure including the above.

[0275] <Variation 3> As a modification of the transistor 21B shown in FIG. 13(B) of the first embodiment, As shown in (B), a channel in which an insulating film functioning as a protective film is provided on an oxide semiconductor film. A protective structure can be provided.

[0276] The transistor 21_A shown in FIG. 21A has a protective film formed on the oxide semiconductor film 68. The insulating film 101 is formed in the same manner as the insulating film 82, for example. It is possible.

[0277] Alternatively, as in a transistor 21_B illustrated in FIG. 21B, The insulating film 101A to 101E are obtained by providing openings in the insulating film that functions as a protective film. It may also be configured as follows.

[0278] <Variation 4> 22(A) to 22(C) show modifications of the conductive film 86 shown in FIG. 15(B) of the first embodiment. ) will be used to explain.

[0279] The conductive film 86_A illustrated in FIG. 22A is the oxide semiconductor film 68 included in the transistor 21B. Therefore, the transistor 21B is highly reliable. To create a transistor with a dual gate structure that has a large on-current and high field-effect mobility Thus, a display device with excellent display quality can be manufactured.

[0280] Alternatively, as shown in FIG. 22B, the oxide semiconductor film 68 of the transistor 21B may be The conductive film 86_B provided on the substrate 81 is electrically separated from the conductive film 86 used as a pixel electrode. By adopting this configuration, the conductive film 86 and the conductive film 86_B can be controlled to have different potentials. It is possible.

[0281] Alternatively, as shown in FIG. 22(C), a conductive film 86_C separated by the conductive film 76 is formed as a conductive film. The area overlapping with the film 76 may be used as a boundary to separate the film 76 from the other area.

[0282] <Variation 5> 23(A) and 23(B) are diagrams showing a modification of the cross section taken along line AB in FIG. 7 of the first embodiment. This will be used to explain.

[0283] As shown in FIG. 23(A), the conductive film 86 is formed in a comb-like shape (FIG. 23(A) shows the cross-sectional shape). The electrodes may be formed so that the paired electrodes are flat. The common electrode paired with the conductive film 86 functioning as a pixel electrode is formed of the metal oxide film 70F. Just do that.

[0284] Alternatively, as shown in FIG. 23(B), the conductive film 86 may be formed in a comb-like shape (the cross-sectional shape in FIG. 23(B) is In this case, the transistor may be formed to have a common electrode. The conductive film 74 of the transistor 21B is connected to the metal oxide film 70F, and the metal oxide film 70G may be used as a pixel electrode.

[0285] <Variation 6> A modification of the cross-sectional view taken along line AB in FIG. 7 of the first embodiment will be described with reference to FIG. 24. In particular, the light-shielding film BM and the color filters 53R and 53B provided on the substrate 90 side are A modified example of the above will be described.

[0286] This configuration simplifies the structure of the substrate 90, and the electrodes of the touch panel, etc., can be mounted on the substrate 90. This can make the formation easier.

[0287] <Variation 7> 25(A) and 25(B) are diagrams showing a modification of the cross section taken along line AB in FIG. 7 of the first embodiment. This will be used to explain.

[0288] FIG. 25(A) shows a cross-sectional view of a sub-pixel having an EL element 113 as a display element. The EL element 113 is provided with an insulating layer to improve the flatness of the surface on which the EL element 113 is provided. It is formed after forming the insulating film 110. On the insulating film 110, An insulating film 114 is formed. Then, an EL layer 111 is formed on the conductive film 86 which functions as one of the electrodes. A conductive layer 112 which functions as the other electrode is formed.

[0289] In the case of the configuration of Figure 25(A), by combining the configuration of Figure 24, it becomes as shown in Figure 25(B). In Figures 25(A) and 25(B), the arrows indicate the emission of light.

[0290] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0291] (Embodiment 3) In the embodiment, in the transistor included in the display device described in the above embodiment, One embodiment applicable to an oxide semiconductor film will be described.

[0292] The oxide semiconductor film is an oxide semiconductor having a single crystal structure (hereinafter referred to as a single-crystal oxide semiconductor), Polycrystalline oxide semiconductors (hereinafter referred to as polycrystalline oxide semiconductors) and microcrystalline oxides A semiconductor having an amorphous structure (hereinafter referred to as a microcrystalline oxide semiconductor) and an oxide semiconductor having an amorphous structure (hereinafter referred to as a The oxide semiconductor film may be formed of one or more of the following: The oxide semiconductor film may be a CAAC-OS film. The oxide semiconductor may be composed of an oxide semiconductor having a crystal grain and a crystal structure. The AAC-OS and the microcrystalline oxide semiconductor will be described.

[0293] First, the CAAC-OS film will be described.

[0294] The CAAC-OS film is one of oxide semiconductor films having a plurality of crystal parts aligned along the c-axis.

[0295] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a crystalline microscope, clear boundaries between the crystals, i.e., crystal boundaries, are clearly visible. It is not possible to confirm the grain boundary. It can be said that the AC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0296] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). ) It can be confirmed that the metal atoms are arranged in layers in the crystalline part. Each layer has a surface on which the CAAC-OS film is formed (also referred to as a surface on which the CAAC-OS film is formed) or an uneven surface on which the CAAC-OS film is formed. The shape reflects this and is aligned parallel to the surface on which the CAAC-OS film is formed or the top surface.

[0297] On the other hand, the CAAC-OS film was observed by TEM from a direction approximately perpendicular to the sample surface (planar TEM). When observed, it was found that the metal atoms were arranged in triangular or hexagonal shapes in the crystals. However, there is no regularity in the arrangement of metal atoms between different crystal parts. stomach.

[0298] FIG. 26(a) is a cross-sectional TEM image of the CAAC-OS film. This is a cross-sectional TEM image of 6(a) enlarged, with the atomic arrangement emphasized for easier understanding. It is displayed.

[0299] Figure 26(c) shows the area surrounded by a circle (diameter approximately 4n) between AO and A' in Figure 26(a). m) are local Fourier transform images. From Figure 26(c), it is clear that the c-axis orientation is In addition, the orientation of the c-axis is different between A-O and O-A', so different gradients are observed. In addition, the c-axis angles between the A and A crystals are 14.3° and 16.6°. 26.4°, and so on. Between these, the c-axis angle gradually changes continuously from -18.3° to -17.6° to -15.9°. It is clear that this is becoming more and more common.

[0300] When electron diffraction is performed on the CAAC-OS film, spots (bright spots) indicating orientation are observed. For example, a potential difference of 1 nm to 30 nm is measured on the top surface of the CAAC-OS film. When electron diffraction using a sagittal beam (also called nanobeam electron diffraction) is performed, spots are observed. (See Figure 27(A)).

[0301] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It turns out that there are.

[0302] Most of the crystals in the CAAC-OS film are cubes with sides of less than 100 nm. Therefore, the crystal part included in the CAAC-OS film has a side length of 10n This also includes cases where the size fits within a cube of less than 100 mm, less than 5 nm, or less than 3 nm. In addition, multiple crystals in the CAAC-OS film are connected to form a single large crystal region. For example, in a planar TEM image, 2 Over 5μm 2 More than or equal to 1000 μm 2 Crystal regions with more than this size may be observed.

[0303] X-ray diffraction (XRD) was performed on the CAAC-OS film. For example, a CAAC-OS film with InGaZnO4 crystals was found by structural analysis using the device. In the out-of-plane analysis, a peak was observed at a diffraction angle (2θ) of approximately 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. This indicates that the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis is approximately aligned on the surface on which the film is formed or on the upper surface. It can be seen that it is oriented in a substantially vertical direction.

[0304] On the other hand, in-pl X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In the analysis by the ane method, a peak may appear at 2θ around 56°. This is attributed to the (110) plane of the InGaZnO4 crystal. In the case of a semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is set as the axis (φ axis). When the sample is rotated and analyzed (φ scan), the crystal plane equivalent to the (110) plane is In contrast, in the case of the CAAC-OS film, 2θ is set to 5 Even when the φ is fixed at around 6° and scanned, no clear peak appears.

[0305] From the above, it is concluded that the a-axis and b-axis orientations are inconsistent between different crystal regions in the CAAC-OS film. Although it is regular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface to be formed or the upper surface. Therefore, the layered arrangement confirmed by the cross-sectional TEM observation mentioned above is consistent with the above. Each layer of aligned metal atoms is a plane parallel to the ab plane of the crystal.

[0306] The crystalline part is formed when the CAAC-OS film is formed or when a crystallization process such as a heat treatment is performed. As described above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed or the surface on which the CAAC-OS film is formed. The orientation of the CAAC-OS film is parallel to the normal vector of the top surface. When the shape is changed by etching, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed. Or it may not be parallel to the normal vector of the upper surface.

[0307] Furthermore, the distribution of c-axis oriented crystal parts in the CAAC-OS film does not need to be uniform. For example, the crystalline part of the CAAC-OS film is formed by crystal growth from the vicinity of the top surface of the CAAC-OS film. When the crystal is formed by this method, the region near the top surface has a larger amount of c-axis oriented crystals than the region near the surface on which the crystal is formed. In addition, the CAAC-OS film containing impurities may have a high ratio of The added region is transformed, forming regions with different proportions of c-axis oriented crystals. This sometimes happens.

[0308] In addition, the out-of-plane method of CAAC-OS film with InGaZnO4 crystals In the analysis by , in addition to the peak at 2θ around 31°, a peak also appeared at 2θ around 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in part of the CAAC-OS film. The CAAC-OS film contains crystals that do not have a 2θ of around 31°. It is preferable that the peak is exhibited at 2θ of around 36° and that the peak is not exhibited at 2θ of around 36°.

[0309] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. These are elements other than the main components of the oxide semiconductor film, such as silicon and transition metal elements. The elements that bond to oxygen more strongly than the metal elements that constitute the oxide semiconductor film, such as fluorine, are oxidized. By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide have an atomic radius (or molecular radius) is large, and when it is contained inside the oxide semiconductor film, The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement and cause a decrease in crystallinity. Objects can act as carrier traps or carrier sources.

[0310] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in the semiconductor film can become carrier traps or trap hydrogen, It can be a source of carrier generation.

[0311] Low impurity concentration and low defect level density (low oxygen vacancies) are called high purity intrinsic or The term "substantially highly purified intrinsic" refers to a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film. Since there are fewer carrier generation sources, the carrier density can be reduced. A transistor using an oxide semiconductor film has electrical characteristics such as a negative threshold voltage ( It is also called marion.) It is rare for it to become high purity genuine or substantially high purity genuine. The oxide semiconductor film has few carrier traps. A transistor using such a material has little fluctuation in electrical characteristics and is highly reliable. Note that it takes a long time for charges trapped in the carrier traps in the oxide semiconductor film to be released. The time between the charges is long and the charge may behave as if it is a fixed charge. However, a transistor using an oxide semiconductor film with a high density of defect states has unstable electrical characteristics. There are cases where this happens.

[0312] In addition, transistors using CAAC-OS films show improved electrical characteristics when irradiated with visible light or ultraviolet light. The fluctuation is small.

[0313] Next, a microcrystalline oxide semiconductor film will be described.

[0314] In the microcrystalline oxide semiconductor film, crystal parts can be clearly seen in the TEM image. The crystal part contained in the microcrystalline oxide semiconductor film may have a size of 1 nm or more and 100 nm or less. , or 1 nm to 10 nm in size. Nanocrystals (nc) are microcrystals of 1 nm to 3 nm or less. The oxide semiconductor film having nc-OS (nanocrystalline Oxide Semiconductor Film) The nc-OS film is called a TE film. In the M observation image, the grain boundaries may not be clearly visible.

[0315] The nc-OS film is a microscopic region (e.g., a region of 1 nm to 10 nm, especially a region of 1 nm or more). The nc-OS film has a periodic atomic arrangement in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystal parts. Therefore, no orientation is observed throughout the film. Therefore, depending on the analytical method, the nc-OS film may be indistinguishable from an amorphous oxide semiconductor film. For example, an XRD apparatus using X-rays with a diameter larger than that of the crystals is used for nc-OS films. When structural analysis is performed using the out-of-plane method, the crystal plane is shown. In addition, the probe diameter ( For example, electron diffraction (also called selected area electron diffraction) is performed using an electron beam of 50 nm or more. On the other hand, for the nc-OS film, Nanobeam electron diffraction using an electron beam with a probe diameter close to or smaller than the size of the crystal part Furthermore, nanobeam electron diffraction was performed on the nc-OS film. When the nc When nanobeam electron diffraction was performed on the -OS film, multiple spots were observed within the ring-shaped region. This may be the case (see Figure 27(B)).

[0316] The nc-OS film is an oxide semiconductor film with higher order than an amorphous oxide semiconductor film. Therefore, the nc-OS film has a lower density of defect states than the amorphous oxide semiconductor film. In the nc-OS film, there is no regularity in the crystal orientation between different crystal parts. The S film has a higher defect state density than the CAAC-OS film.

[0317] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, or a CA The AC-OS film may be a laminated film having two or more kinds of films.

[0318] When an oxide semiconductor film has multiple structures, the structure can be analyzed using nanobeam electron diffraction. may be possible.

[0319] FIG. 27C shows an electron gun chamber 170, an optical system 172 below the electron gun chamber 170, and an optical system 172 below the electron gun chamber 170. 2, a sample chamber 174 under the sample chamber 174, an optical system 176 under the sample chamber 174, and an observation under the optical system 176. chamber 180, a camera 178 installed in the observation chamber 180, and a film chamber below the observation chamber 180. The transmission electron diffraction measurement device shown in FIG. 1 has a camera 178 inside an observation chamber 180. The film chamber 182 does not necessarily have to be provided.

[0320] FIG. 27(D) shows the internal structure of the transmission electron diffraction measurement device shown in FIG. 27(C). Inside the transmission electron diffraction measurement device, electrons emitted from an electron gun installed in the electron gun chamber 170 is irradiated onto a substance 188 placed in a sample chamber 174 via an optical system 172. The electrons passing through the 8 are projected onto a fluorescent screen 192 installed inside an observation chamber 180 via an optical system 176. On the fluorescent screen 192, a pattern appears according to the intensity of the incident electrons, The electron diffraction pattern can be measured.

[0321] The camera 178 is installed facing the fluorescent screen 192 and captures the pattern that appears on the fluorescent screen 192. The center of the lens of the camera 178 and the center of the fluorescent screen 192 can be photographed. The angle between the line passing through the line and the upper surface of the fluorescent screen 192 is, for example, 15° or more and 80° or less. The angle should be between 30° and 75°, or between 45° and 70°. The smaller the angle, the easier it is for the camera to The transmission electron diffraction pattern taken by the laser 178 is highly distorted. If the angle is known, it is also possible to correct distortions in the resulting transmission electron diffraction pattern. In some cases, the camera 178 may be installed in the film chamber 182. For example, Even if the camera 178 is installed in the film chamber 182 so as to face the direction of incidence of the electrons 184, In this case, a transmission electron diffraction pattern with little distortion is captured from the rear surface of the fluorescent screen 192. It is possible.

[0322] A holder for fixing a substance 188, which is a sample, is installed in the sample chamber 174. The holder is constructed to be transparent to electrons passing through the material 188. The holder may have a function to move the substance 188 in the X-axis, Y-axis, Z-axis, etc. The dynamic function can be, for example, 1 nm or more and 10 nm or less, 5 nm or more and 50 nm or less, 10 nm or more and 1 00nm or less, 50nm to 500nm, 100nm to 1μm or less The optimum range for these parameters depends on the structure of the material 188. Just set it.

[0323] Next, the transmission electron diffraction pattern of the substance is measured using the above-mentioned transmission electron diffraction measurement device. The method will be explained.

[0324] For example, as shown in FIG. 27(D), the irradiation position of the electron 184, which is a nanobeam, in the material By changing (scanning) the In this case, if the substance 188 is a CAAC-OS film, as shown in FIG. If the material 188 is an nc-OS film, a diffraction pattern similar to that shown in FIG. 27(B) is observed. ) is observed.

[0325] By the way, even if the material 188 is a CAAC-OS film, it may be partially composed of nc-OS films. Therefore, the quality of the CAAC-OS film can be determined by the diffraction pattern. , the ratio of the area where the diffraction pattern of the CAAC-OS film is observed in a certain range (CAA For example, in a high-quality CAAC-OS film, If present, the CAAC conversion rate is 50% or more, preferably 80% or more, and more preferably 90% or more. The diffraction pattern is different from that of the CAAC-OS film. The percentage of the area where this is observed is denoted as the non-CAAC rate.

[0326] As an example, immediately after film formation (denoted as as-sputtered), or in an oxygen-containing atmosphere The top surface of each sample with the CAAC-OS film after the 450°C heat treatment was scanned. Transmission electron diffraction patterns were obtained while scanning at a speed of 5 nm / sec for 60 sec. The diffraction pattern was observed while scanning, and the observed diffraction pattern was captured as a still image every 0.5 seconds. The CAAC conversion rate was calculated by converting the electron beam. The same measurement was carried out on six samples. The average value of six samples was used for calculation.

[0327] The CAAC ratio of each sample is shown in Figure 28(A). The AC conversion rate was 75.7% (non-CAAC conversion rate was 24.3%). The CAAC content of the treated CAAC-OS film was 85.3% (non-CAAC content was 14.7%). It can be seen that the CAAC conversion rate is higher after heat treatment at 450°C than immediately after film formation. That is, the non-CAAC rate is low due to heat treatment at high temperatures (for example, 400°C or higher). In addition, in the case of heat treatment below 500°C, It can be seen that a CAAC-OS film with a high CAAC content can be obtained.

[0328] Here, most of the diffraction patterns different from those of the CAAC-OS film are similar to those of the nc-OS film. In addition, the amorphous oxide semiconductor film was not observed in the measurement area. Therefore, it is possible that a region with a structure similar to that of the nc-OS film was formed by the heat treatment. It is suggested that the CAAC domain is rearranged and formed under the influence of the structure of the adjacent domain.

[0329] 28(B) and 28(C) show the CAAC-O film immediately after deposition and after heat treatment at 450°C. 28(B) and 28(C) are planar TEM images of the S film. It can be seen that the CAAC-OS film after the heat treatment at 0°C has a more uniform film quality. It can be seen that the film quality of the CAAC-OS film is improved by the heat treatment at high temperature.

[0330] By using this measurement method, it is possible to analyze the structure of oxide semiconductor films with multiple structures. This may occur.

[0331] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0332] (Fourth embodiment) As described in Embodiment 1, a transistor including an oxide semiconductor film has a Therefore, the current value (off-state current value) of the electric signal such as the image signal can be controlled to a low value. The retention time can be extended and the write interval can also be set longer.

[0333] In the display device of this embodiment, by using a transistor with a low off-state current, at least The display device can be configured to perform display using two driving methods (modes). The drive method is a conventional display device drive method in which data is rewritten sequentially for each frame. The second driving mode is a method in which data is rewritten after the data writing process is executed. This is a driving method that stops the refresh rate. do.

[0334] The first driving mode is used to display moving images. The second driving mode is used to display still images. Since the data remains unchanged, there is no need to rewrite the data for each frame. When displaying still images, the second driving mode can be used to eliminate screen flicker. Both can reduce power consumption.

[0335] In addition, the capacitance element of the pixel applied to the display device of this embodiment is Therefore, it is possible to extend the time for which the potential of the pixel electrode is maintained. A driving mode that reduces the refresh rate can be applied. Even when a drive mode that reduces the flash rate is applied, the voltage held by the pixel changes. This makes it possible to suppress flickering for a long period of time, thereby preventing the user from perceiving image flicker. Therefore, it is possible to reduce power consumption and improve display quality.

[0336] Here, the effect of reducing the refresh rate will be described.

[0337] There are two types of eye fatigue: nervous fatigue and muscular fatigue. Continuing to look at the light-emitting or flashing screen of a display device stimulates the retina, nerves, and brain of the eye. Muscle fatigue is caused by the ciliary muscles used to adjust focus. It is something that makes you tired by overworking your body.

[0338] FIG. 29(A) is a schematic diagram showing the display of a conventional display device. In the case of a conventional display device, the image is rewritten 60 times per second. Looking at such a screen for a long time can stimulate the retina, nerves, and brain of the user, causing eye fatigue. was likely to be caused.

[0339] In one embodiment of the present invention, a transistor with extremely low off-state current, for example, A transistor including an oxide semiconductor is used. The capacitance element can be made large in area. This suppresses charge leakage and makes it possible to make potential changes more gradual, Even if the frame frequency is lowered, the brightness of the display device can be suppressed.

[0340] That is, as shown in FIG. 29(B), for example, the image can be rewritten once every five seconds. This allows the same image to be viewed as much as possible, reducing the flickering of the screen that is visible to the user. This reduces the stimulation of the retina, nerves and brain of the user's eyes, and reduces nervous system fatigue. It will be reduced.

[0341] According to one embodiment of the present invention, a display device that is easy on the eyes can be provided.

[0342] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. can be used in appropriate combination.

[0343] (Embodiment 5) In this embodiment, structural examples of electronic devices to which the display device of one embodiment of the present invention is applied will be described. In addition, in this embodiment, a display module to which the display device of one embodiment of the present invention is applied will be described. This will be explained with reference to FIG.

[0344] The display module 8000 shown in FIG. 30 is made up of an upper cover 8001 and a lower cover 8002. In between, touch panel 8004 connected to FPC8003, and touch panel 8005 connected to FPC8005 Display panel 8006, backlight unit 8007, frame 8009, printed circuit board 8010 and a battery 8011. The reader 8011, the touch panel 8004, etc. may not be provided.

[0345] The display device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0346] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel 8005. The shape and dimensions can be changed appropriately to match the size of 006.

[0347] The touch panel 8004 is a resistive or capacitive touch panel. 8006. In addition, the opposing substrate (sealing substrate) of the display panel 8006 ) can also be equipped with a touch panel function. It is also possible to provide an optical sensor in each pixel of the touch panel to make it an optical touch panel. Alternatively, a touch sensor electrode is provided in each pixel of the display panel 8006, and a capacitive touch panel is formed. It is also possible to use a panel.

[0348] The backlight unit 8007 includes a light source 8008. It may be provided at the end of the unit 8007 and configured to use a light diffusion plate.

[0349] The frame 8009 protects the display panel 8006 and also prevents the operation of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the frame. The frame 8009 may also function as a heat sink.

[0350] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply to the power supply circuit can be an external commercial power supply or Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0351] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0352] 31(A) to 31(H) and 32(A) to 32(D) are diagrams showing electronic devices. These electronic devices include a housing 5000, a display unit 5001, a speaker 5003, and a LE. D lamp 5004, operation key 5005 (including power switch or operation switch), connection Terminal 5006, sensor 5007 (force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance , light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, voltage, power, radiation (including functions to measure flow rate, humidity, gradient, vibration, odor or infrared rays), It can have a 5008, etc.

[0353] FIG. 31(A) shows a mobile computer, which includes, in addition to the above, a switch 5009 , an infrared port 5010, etc. FIG. 31(B) shows a portable terminal equipped with a recording medium. A portable image reproducing device (for example, a DVD reproducing device) is also included. It can have a display unit 5002, a recording medium reading unit 5011, etc. It is a group-type display, and in addition to the above, it has a second display unit 5002, a support unit 5012 , earphones 5013, etc. FIG. 31(D) shows a portable gaming machine. In addition to the above, it may have a recording medium reading unit 5011, etc. It is a digital camera with a TV receiving function, and in addition to the above, it also has an antenna 5014, The mobile phone may have a shutter button 5015, an image receiving unit 5016, etc. It is a belt-type gaming machine, and in addition to the above, it has a second display unit 5002, a recording medium reading unit 5011, , etc. FIG. 31(G) shows a television receiver, which, in addition to the above, has It can have a tuner, an image processor, etc. FIG. 31(H) shows a portable television receiver. In addition to the above, it has a charger 5017 capable of transmitting and receiving signals, etc. FIG. 32(A) shows a display, which includes, in addition to the above, a support base 5018, FIG. 32(B) shows a camera, which has external connections in addition to the above. It may have a port 5019, a shutter button 5015, an image receiving unit 5016, etc. FIG. 32(C) shows a computer, which, in addition to the above, has a pointing device 5 020, an external connection port 5019, a reader / writer 5021, etc. FIG. 32(D) shows a mobile phone, which in addition to the above-mentioned components includes a transmitting unit, a receiving unit, a mobile phone / transmitter It may have a tuner for one segment partial reception services for mobile terminals, etc.

[0354] The electronic devices shown in FIGS. 31(A) to 31(H) and 32(A) to 32(D) are For example, various information (still images, videos, text images, etc.) can be stored. ) on the display, touch panel function, calendar, date or time display, etc. Functions for controlling processing using various software (programs), wireless communication functions , the ability to connect to various computer networks using wireless communication functions, wireless communication functions A function to send or receive various data using the program recorded on the recording medium. Or, it can have a function of reading out data and displaying it on a display unit. In electronic devices having such a display unit, one display unit is used to mainly display image information, and another display unit is used to A function that mainly displays text information on one display unit, or a function that takes parallax into account on multiple displays By displaying the image, it is possible to have a function of displaying a three-dimensional image. In electronic devices having an image receiving unit, there are functions for taking still images, taking moving images, and Function to automatically or manually correct captured images, and to save captured images to a recording medium (external or camera) It can have functions such as saving the captured image to a camera (built-in), displaying the captured image on the display, etc. In addition, the electronic devices shown in Figures 31(A) to 31(H) and Figures 32(A) to 32(D) The functions that the container can have are not limited to these, and the container can have a variety of functions.

[0355] The electronic device described in this embodiment has a display unit for displaying some information. It is characterized by the following.

[0356] Next, application examples of the display device will be described.

[0357] FIG. 32(E) shows an example in which a display device is integrated with a building. ) includes a housing 5022, a display unit 5023, a remote control device 5024 as an operation unit, and a speaker. The display device is a wall-mounted type that is integrated with the building, and the installation space is limited. It can be installed without requiring a large space.

[0358] FIG. 32(F) shows another example in which a display device is provided inside a building as an integral part of the building. The display module 5026 is attached to the unit bath 5027. The bather can then view the display module 5026.

[0359] In this embodiment, a wall and a unit bath are used as examples of buildings. The form is not limited to this, and the display device can be installed in various buildings.

[0360] Next, an example in which the display device is provided integrally with a moving object will be described.

[0361] FIG. 32(G) is a diagram showing an example in which the display device is installed in an automobile. The control unit 5028 is attached to the body 5029 of the automobile and controls the operation of the body or the inside and outside of the automobile. It is possible to display information entered from the navigation function on demand. may have

[0362] FIG. 32(H) is a diagram showing an example in which a display device is integrated into a passenger airplane. FIG. 32(H) shows a display module 503 mounted on a ceiling 5030 above the seats of a passenger airplane. 1 is provided. The display module 5031 is a diagram showing the shape of the display module when in use. The ceiling 5030 is attached to the ceiling 5030 via a hinge portion 5032. The expansion and contraction of the display module 503 allows passengers to view the display module 5031. 1 has the function of displaying information when operated by passengers.

[0363] In this embodiment, an automobile body and an airplane body are exemplified as moving bodies. However, it is not limited to this, and it can be installed on various things such as motorcycles, four-wheeled vehicles (including automobiles, buses, etc.), trains (including monorails, railways, etc.), ships, etc. In addition, it can be installed on various things such as motorcycles, four-wheeled vehicles (including automobiles, buses, etc.), trains (including monorails, railways, etc.), ships, etc.

[0364] In the present specification, etc., in the figure or text described in a certain embodiment, it is possible to extract a part thereof and form an aspect of the invention. Therefore when a figure or text describing a certain part is described, the content obtained by extracting a part of the figure or text is also disclosed as an aspect of the invention and can form an aspect of the invention. Therefore, for example, in a drawing or text in which a single or plural number of active elements (such as transistors, diodes, etc.), wirings, passive elements (such as capacitive elements, resistive elements, etc.), conductive layers, insulating layers, semiconductor layers, organic materials, inorganic materials, parts, devices, operation methods, manufacturing methods, etc. are described, it is possible to extract a part thereof and form an aspect of the invention shall be considered possible. For example, from a circuit diagram composed of N (N is an integer) circuit elements (such as transistors, capacitive elements, etc.), it is possible to extract M (M is an integer and M < N) circuit elements (such as transistors, capacitive elements, etc.) and form an aspect of the invention. As another example from a cross-sectional view composed of N (N is an integer) layers, it is possible to extract M (M is an integer and M < N) layers and form an aspect of the invention. As yet another example from a flowchart composed of N (N is an integer) elements, it is possible to extract M (M is an integer and M < N ) elements and form an aspect of the invention. In the present specification, etc., in the figure or text described in a certain embodiment, it is possible to extract a part thereof and form an aspect of the invention shall be considered possible. For example, from a circuit diagram composed of N (N is an integer) circuit elements (such as transistors, capacitive elements, etc.), it is possible to extract M (M is an integer and M < N) circuit elements (such as transistors, capacitive elements, etc.) and form an aspect of the invention. As another example from a cross-sectional view composed of N (N is an integer) layers, it is possible to extract M (M is an integer and M < N) layers and form an aspect of the invention. As yet another example from a flowchart composed of N (N is an integer) elements, it is possible to extract M (M is an integer and M < N ) elements and form an aspect of the invention. In addition, from a cross-sectional view composed of N (N is an integer) layers, it is possible to extract M (M is an integer and M < N) layers and form an aspect of the invention. Further, as another example from a flowchart composed of N (N is an integer) elements, it is possible to extract M (M is an integer and M < N ) elements and form an aspect of the invention.

[0365] In the present specification, etc., in the figure or text described in a certain embodiment, it is possible to extract a part thereof and form an aspect of the invention When at least one specific example is described, the generic concept of that specific example must be derived. This will be readily understood by those skilled in the art. If at least one specific example is described in the drawings or text, The concept is also disclosed as an aspect of the invention and may constitute an aspect of the invention. It is possible.

[0366] In this specification, at least the contents shown in the drawings (or even a part of the drawings) is disclosed as one aspect of the invention and can constitute one aspect of the invention. Therefore, if a certain content is shown in a diagram, it can be explained in writing. Even if there is no such content, the content is disclosed as one aspect of the invention, and Similarly, even if a part of the drawings is taken out, it is possible to construct it as one aspect of the invention. and can constitute one embodiment of the invention. [Explanation of symbols]

[0367] L1 wiring L2 cabling L3 cabling L4 cabling L5 wiring 10 Pixel section 11 Circuits 12 circuits 13 pixels 14 subpixels 14B subpixel 14G subpixel 14R subpixel 14W subpixel 15 scan lines 15_m Conductive film 16 Signal line 16_n Conductive film 17 Capacitance line 17p conductive film 21 Transistor 21_A Transistor 21_B Transistor 21B transistor 21G transistor 21R transistor 21W transistor 22 Capacitor element 22B Capacitor 22G capacitive element 22R capacitance element 22W Capacitive element 23 Liquid crystal element 23B Liquid crystal element 23G liquid crystal element 23R liquid crystal element 23W liquid crystal element 25 Capacitance Line 31 Transistor 32 transistors 33 Capacitor element 34 transistors 35 Light-emitting element 36 Wiring 37 Wiring 38 Wiring 41B Oxide semiconductor film 41G Oxide semiconductor film 41R Oxide semiconductor film 41W oxide semiconductor film 43RB metal oxide film 43GW Metal Oxide Film 45B Conductive film 45G conductive film 45R conductive film 45W conductive film 47B Opening 47G opening 47R opening 47W opening 49B Conductive film 49G Conductive film 49R Conductive Film 49W Conductive Film 50RB opening 50GW opening 53B Color Filter 53G Color Filter 53R color filter 53W Light-transmitting layer 55B opening 55G opening 55R opening 55W opening 60 boards 62 Conductive film 64 insulating film 66 Insulating film 67 Oxide semiconductor film 68 Oxide semiconductor film 68A Oxide semiconductor film 68B oxide semiconductor film 68C oxide semiconductor film 69 Oxide semiconductor film 69A Oxide semiconductor film 69B Oxide semiconductor film 69C Oxide semiconductor film 70 Metal oxide film 170 Electron Gun Room 70F metal oxide film 70G Metal Oxide Film 71 Conductive film 172 Optical system 72 Conductive film 174 Sample Room 74 Conductive Film 176 Optical system 76 Conductive Film 77 Insulating Film 178 Cameras 78 Insulating Film 79 Insulating Film 180 Observation Room 80 insulating film 81 insulating film 182 Film Room 82 insulating film 83 Insulating film 84 insulating film 184 electronic 85 Conductive Film 86 Conductive Film 86_A Conductive film 86_B Conductive film 86_C Conductive film 88 Alignment film 188 Substance 90 PCB 192 fluorescent screen 92 insulating film 94 Conductive Film 95 Liquid crystal layer 96 Alignment film 98 insulating film 100 display device 101 insulating film 101A Insulating film 101E Insulating film 110 insulating film 111 EL layer 112 Conductive layer 113 EL element 114 insulating film 200 Display Controller 210 Signal conversion circuit 220 Data signal calculation circuit 230 Backlight Unit 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared port 5011 Recording medium reading unit 5012 Support part 5013 Earphones 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 5018 Support stand 5019 External connection port 5020 pointing device 5021 Reader / Writer 5022 Housing 5023 Display section 5024 Remote control device 5025 Speaker 5026 Display Module 5027 Unit bath 5028 Display Module 5029 Car Body 5030 Ceiling 5031 Display Module 5032 Hinge part 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8007 Backlight Unit 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

[Claim 1] In a display device provided with a pixel having first to fourth sub-pixels, the first to third sub-pixels are sub-pixels having a function of controlling transmission of any one of red, green, and blue light, the fourth subpixel is a subpixel having a function of controlling transmission of white light, a display device in which the area of the opening of the fourth subpixel is smaller than the areas of the openings of the first to third subpixels;

Images