Display device

Abstract

To provide a display device that has high aperture ratio and comprises a capacitive element capable of increasing a capacitance value, and also can achieve a narrow frame.SOLUTION: A transistor comprises a gate electrode on a substrate, an oxide semiconductor film overlapping the gate electrode, a gate insulating film in contact with one face of the oxide semiconductor film, and a pair of conductive films in contact with the oxide semiconductor film. A capacitive element comprises a metal oxide film on the gate insulating film and in contact with one of the pair of conductive films, an inorganic insulating film, and a first translucent conductive film on the inorganic insulating film. A pixel electrode is formed of a second translucent conductive film and is in contact with one of the pair of conductive films. A first gate line, which also serves as a gate electrode, is connected so as to select three sub-pixels among four sub-pixels, and a second gate line is connected so as to select remaining sub-pixels and also select one sub-pixel of a next line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to a display device. In particular, one aspect of the present invention relates to a display device using a liquid crystal element as a display element. The present invention relates to a display device having the above structure.

[0002] The present invention is not limited to the above technical field. The technical field of the invention disclosed in this specification is The present invention relates to a process, a machine, a method, or a manufacturing method. Related 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 mentioned as an example. [Background technology]

[0003] In recent years, color has been achieved by using sub-pixels equipped with color filters of the three primary colors, i.e., red, green, and blue (RGB). For display configurations, a W (white) subpixel is added to RGB to reduce power consumption or improve brightness. Display devices that aim to improve visibility have been proposed (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-295717 Summary of the Invention [Problem to be solved by the invention]

[0005] By adding a W subpixel to the RGB (red, green, blue) color filter subpixels, each The number of wirings required to control the sub-pixels increases. When the number of wirings increases, the number of wirings required to drive the wirings increases. Since the circuit area needs to be large, the frame can be narrowed by incorporating a driving circuit. It gets harder.

[0006] Alternatively, by increasing the number of sub-pixels that make up a pixel, the area of ​​each sub-pixel becomes smaller. This leads to a decrease in the aperture ratio, and makes it difficult to ensure the required capacitance value for the capacitance element. become.

[0007] Therefore, one aspect of the present invention is to provide a novel structure that can suppress an increase in the number of wirings even if the number of sub-pixels is increased. Another object of the present invention is to provide a display device or the like having a narrow frame. It is an object of the present invention to provide a display device or the like having a novel structure that can realize the above. One aspect of the present invention is to provide a display device or the like having a novel configuration that can suppress a decrease in aperture ratio. Another embodiment of the present invention is a method for obtaining a required capacitance value in a capacitor. Another object of the present invention is to provide a display device or the like having a novel structure. One of the objects of the present invention is to provide a display device or the like having a novel structure and excellent display quality. An object of one embodiment of the present invention is to provide a novel display device or the like.

[0008] The problems to be solved by the present invention are not limited to those listed above. The problems to be solved by the present invention may include other problems. This does not preclude the existence of other issues, which are described below and are not mentioned in this section. Problems not mentioned in this section are problems that a person skilled in the art would be able to easily understand by referring to the specification, 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 aspect of the present invention is a pixel array including a first pixel having first to fourth sub-pixels and a pixel array including a pixel array in a row next to the first pixel. The first pixel has a first sub-pixel, a second sub-pixel, and a fourth sub-pixel. A first wiring for applying a signal for selecting the subpixels from the first pixel to the third pixel, and a second wiring for selecting the sub-pixel of the second pixel, the second wiring being This is a display device in which the wiring is used to select sub-pixels 4.

[0010] Another aspect of the present invention is a first pixel having first to fourth sub-pixels, The second pixel has first to fourth sub-pixels arranged in a row, and the first pixel has A first wiring for applying a signal for selecting the first to third subpixels and a second wiring for applying a signal for selecting the first to third subpixels a second wiring for selecting the fourth subpixel, and a first wiring for selecting the first to third subpixels of the second pixel; and a third wiring for selecting a fourth sub-pixel included in the second pixel. This is a display device that is wiring for selecting. Effect of the Invention

[0011] According to one embodiment of the present invention, a novel configuration is provided that can suppress an increase in the number of wirings even if the number of sub-pixels is increased. Alternatively, one embodiment of the present invention can provide a display device or the like that can realize a narrow frame. A display device or the like having a novel structure can be provided. It is possible to provide a display device or the like having a novel configuration that can suppress the deterioration. One aspect of the present invention provides a display device or the like having a novel configuration that can ensure a required capacitance value in a capacitive element. Alternatively, one embodiment of the present invention can provide a display device having a novel structure with excellent display quality. Alternatively, one embodiment of the present invention provides a novel display device, etc. It is possible.

[0012] The effects of the present invention are not limited to those listed above. The effects listed above may include other effects. However, other effects are described below, and are not included in the Effects not mentioned in this section are obvious to those skilled in the art in the specification, drawings, etc. These can be derived from the descriptions and can be extracted appropriately from these descriptions. One aspect of the invention is to provide at least one of the above-listed advantages and / or other advantages. Therefore, one embodiment of the present invention may have the above-listed effects. In some cases this is not the case. [Brief description of the drawings]

[0013] [Figure 1] 1A and 1B are a block diagram and a circuit diagram illustrating one embodiment of a display device. [Diagram 2] FIG. 1 is a top view illustrating one embodiment of a display device. [Diagram 3] FIG. 1 is a top view illustrating one embodiment of a display device. [Figure 4] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Diagram 5] 1A to 1C are cross-sectional views illustrating one mode of a manufacturing method of a display device. [Figure 6] 1A to 1C are cross-sectional views illustrating one mode of a manufacturing method of a display device. [Figure 7] 1A to 1C are cross-sectional views illustrating one mode of a manufacturing method of a display device. [Figure 8] 1A to 1C are cross-sectional views illustrating one mode of a manufacturing method of a display device. [Figure 9] 1A to 1C are cross-sectional views illustrating one mode of a manufacturing method of a display device. [Figure 10] 1A to 1C are cross-sectional views illustrating one mode of a manufacturing method of a display device. [Figure 11] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 12] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 13] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 14] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 15] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 16] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 17] Cross-sectional TEM image and local Fourier transform image of an oxide semiconductor. [Figure 18] 1A and 1B are diagrams showing a nanobeam electron diffraction pattern of an oxide semiconductor film and an example of a transmission electron diffraction measurement apparatus. [Figure 19] An example of structural analysis using transmission electron diffraction measurements, and a planar TEM image. [Figure 20] FIG. 1 is a conceptual diagram showing an example of a method for driving a display device. [Figure 21] FIG. 2 is a diagram illustrating a display module. [Figure 22] 1A and 1B are diagrams illustrating external views of an electronic device according to an embodiment. [Diagram 23] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 24] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Diagram 25] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 26] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 27] FIG. 1 is a circuit diagram illustrating one mode of a display device. [Figure 28] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 29] FIG. 4 is a diagram illustrating the temperature dependence of resistivity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment will be described with reference to the drawings. However, the embodiment may be different from the embodiment. The present invention can be implemented in any manner without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that various modifications may be made to the embodiments and details of the present invention. The present invention should not be construed as being limited to the description of the following embodiments. In the structure of the invention, reference numerals indicating the same objects are common among different drawings.

[0015] In addition, in the drawings, the size, layer thickness, or area may be exaggerated for clarity. Therefore, the scale is not necessarily limited to that shown in the drawings. The above is a formula, and is not limited to the shapes or values ​​shown in the drawings. For example, Variations in signals, voltages, or currents due to timing differences, or variations in signals, voltages, Or, it is possible to include current variation.

[0016] In this specification, a transistor is a small element including a gate, a drain, and a source. It is an element that has at least three terminals. And the drain (drain terminal, drain region) A channel is formed between the source (source terminal, source region or source electrode) and the The transistor has a drain region, and a current can flow through the drain, the channel region, and the source. This is what we have in mind.

[0017] 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 a source or a drain. One of the source and drain is referred to as the first terminal, and the other of the source and drain is referred to as the second terminal. It may be indicated.

[0018] 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.

[0019] 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" means that there is an object between A and B that has some electrical effect. When a device is connected to a power source, it enables the transmission and reception of electrical signals between A and B.

[0020] In this specification, the terms "above" and "below" that indicate a positional relationship between components are used. The relationship between the components is used for convenience in describing 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.

[0021] The arrangement 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. Even if the circuit is shown as a single circuit block, in the actual circuit or domain, In some cases, processing is provided in multiple circuit blocks.

[0022] 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 a static electric field It is said.

[0023] Generally, potentials and voltages are relative. Therefore, the ground potential is always It is not necessarily limited to 0 volts.

[0024] In this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. Therefore, it includes the case where the angle is between -5° and 5°. "Straight" refers to a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. This also includes cases where the angle is between 85° and 95°.

[0025] In this specification, when the crystal is a trigonal or rhombohedral crystal, it is represented as a hexagonal crystal system. .

[0026] (Embodiment 1) In this embodiment, a structure of a pixel included in a display device which is one embodiment of the present invention will be described with reference to the drawings. This will be explained in light of the above.

[0027] 1A shows a display device 100 as an example of a display device. 100 is a pixel section 11, a scanning line driving circuit 12, and a signal line driving circuit 16, each of which is parallel to each other. and a scanning line 17, which is disposed in parallel with the scanning line 12 and has a potential controlled by a scanning line driving circuit 12. , each of which is arranged in parallel or approximately in parallel, and the potentials of which are controlled by a signal line driving circuit 16. The pixel section 11 further includes pixels 13 arranged in a matrix. The pixel has a plurality of sub-pixels 14. Also, each of the sub-pixels 14 is parallel to the signal line 25. The capacitor line 19 is disposed in parallel to the potential generating circuit 18 and provides the potential to the potential generating circuit 18 .

[0028] The display device includes a driving circuit for driving a plurality of pixels. The control circuit, power supply circuit, signal generation circuit, backlight module, etc., arranged on the board The scanning line driving circuit 12 includes the scanning lines 17. The potential generating circuit 18 is a circuit having a function of driving the is a circuit having a function of generating a potential to be applied to the capacitance line 19, and may be simply referred to as a circuit. The signal line driver circuit 16 is a circuit having a function of driving the signal line 25. This is sometimes called a circuit.

[0029] Pixel 13 is a sub-pixel that transmits four colors of light, the three primary colors RGB (red, green, and blue) plus W (white). 14 and has the function of displaying colors according to additive color mixing of these lights. The sub-pixels that control the transmission of light have colored films that convert the light from the light source into light of each color. The sub-pixel that controls the transmission of W light is transmitted as is if the light source is white. In addition to the white color obtained by additive mixing of RGB, white can also be obtained by mixing complementary colors. The color may be white.

[0030] The white color obtained from the sub-pixels that transmit RGB light is the light that has passed through the color filter. The white color 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 this way, the white light obtained by the sub-pixel that transmits the W light can be transmitted as is. The color is white, which can be obtained without any significant decrease in the intensity of the light emitted from the light source. Therefore, the white color obtained by the sub-pixels transmitting the RGBW light obtained in one embodiment of the present invention is R This white light has a higher light intensity than the white light obtained by the sub-pixel that transmits the GB light. In other words, In other words, the white color obtained by the sub-pixels that transmit RGBW light is a white color with reduced loss in light intensity. Therefore, in the configuration according to one aspect of the present invention, sub-pixels that transmit RGBW light are used. Compared to obtaining white using a display device with sub-pixels that transmit RGB light, As a result, the display device can reduce power consumption.

[0031] The subpixel 14 is provided with a scanning signal to control the conductive state of the transistor, and the capacitance element is used to determine the A data signal is held, and a display element is driven in accordance with the amount of charge provided by the data signal. The sub-pixels 14 correspond to the respective colors of RGBW. , and first to fourth sub-pixels.

[0032] The scanning lines 17 are, for example, lines extending from the sub-pixels 14 arranged in a matrix in the pixel section 11. The electrical connections are different for each row. For example, the first scanning line 17 The pixel 13 is electrically connected to the sub-pixel 14 that controls the transmission of R, G, and B light. The second scanning line 17 includes sub-pixels 14 that control the transmission of W light in the pixels 13 in the first row, and electrically connected to a sub-pixel 14 that controls the transmission of W light in the pixel 13 in the second row. The third scanning line 17 controls the transmission of RGB light in the pixels 13 in the second row. The scanning line 17 is electrically connected to the sub-pixel 14 that controls the sub-pixel. This is wiring that provides a signal, and is sometimes simply called wiring.

[0033] The signal lines 25 are, for example, connected to the sub-pixels 14 arranged in a matrix in the pixel section 11. For example, the signal line 25 in the first column is connected to the pixel in the first column. The pixel 13 is electrically connected to the sub-pixel 14 that controls the transmission of R light. The signal line 25 is electrically connected to the sub-pixel 14 that controls the transmission of G light in the pixel 13 in the first column. The signal lines 25 in the third row are electrically connected to the signal lines in the first row. A sub-pixel 14 controls the transmission of B light in the pixel 13, and a sub-pixel 15 controls the transmission of W light. The signal line 25 is electrically connected to the sub-pixel 14. It is wiring that provides a current and is sometimes simply called wiring.

[0034] As an example, the capacitance line 19 in the first column is connected to the pixels 13 in the first to third columns. The capacitance line 19 is electrically connected to the sub-pixel 14 that controls the transmission of RGBW light. This is a wiring for applying a fixed potential to a sub-pixel, and may be simply called a wiring.

[0035] Here, an example of a circuit configuration that can be used for the sub-pixel 14 of the display device shown in FIG. This is shown in Figures 27(A) and (B).

[0036] The subpixel 301 shown in FIG. 27A includes a liquid crystal element 31, a transistor 103, and a capacitor element 105 and has.

[0037] The potential of one of the pair of electrodes of the liquid crystal element 31 is appropriately set according to the specifications of the sub-pixel 301. The alignment state of the liquid crystal element 31 is set by the written data. A common potential (common potential) is applied to one of a pair of electrodes of the liquid crystal element 31 of each element 301. ) may be provided to one of the pair of electrodes of the liquid crystal element 31 for each sub-pixel 301 in each row. A potential may be applied.

[0038] The liquid crystal element 31 controls the transmission or non-transmission of light by the optical modulation effect of the liquid crystal. The optical modulation of liquid crystals is achieved by the electric field applied to the liquid crystal (horizontal electric field, vertical electric field). The liquid crystal element 31 is controlled by a vertical electric field or an oblique electric field. Nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, thermotropic liquid crystal, light Examples of the liquid crystal include ferroelectric liquid crystal, antiferroelectric liquid crystal, and the like.

[0039] The display device having the liquid crystal element 31 can be driven in, for example, a TN mode, a 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, it is possible to use the (First Bend Alignment) mode. There is no limitation, and various liquid crystal elements and driving methods thereof can be used.

[0040] 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 speed of 1 msec or less. In addition, since the liquid crystal exhibiting the blue phase is optically isotropic, no alignment treatment is required. The viewing angle dependency is small.

[0041] In the configuration of the subpixel 301 shown in FIG. 27A, the source electrode of the transistor 103 and One of the drain electrodes is electrically connected to the signal line 25, and the other is a pair of electrodes of the liquid crystal element 31. The gate electrode of the transistor 103 is electrically connected to the other of the scanning lines 17. The transistor 103 is electrically connected to It has a function of controlling the writing of data of a data signal.

[0042] In the configuration of the subpixel 301 shown in FIG. 27A, one of a pair of electrodes of the capacitor 105 is 1 is electrically connected to a capacitance line 19 to which a potential is supplied, and the other is connected to a pair of electrodes of a liquid crystal element 31 The potential value of the capacitance line 19 is determined according to the specifications of the sub-pixel 301. The capacitance element 105 serves as a storage capacitor for storing written data. It has the following functions.

[0043] For example, in a display device having the sub-pixel 301 shown in FIG. 27A, the scanning line driving circuit 12 The sub-pixels 301 in each row are selected in sequence, and the transistors 103 are turned on to output the data signal. Write the data.

[0044] The sub-pixel 301 to which the data has been written is held by turning off the transistor 103. By performing this process row by row, an image can be displayed.

[0045] In addition, the sub-pixel 301 shown in FIG. 27B includes a transistor for switching a display element. 43, a transistor 103 for controlling the driving of the pixel, a transistor 45, and a capacitor element 1 05 and a light-emitting element 41.

[0046] One of the source and drain electrodes of the transistor 43 is connected to a signal The gate electrode of the transistor 43 is electrically connected to the line 25. Electrically connected to the scan line 17 provided.

[0047] The transistor 43 is turned on or off to convert the data of the data signal into a It has the function of controlling writing.

[0048] One of the source electrode and the drain electrode of the transistor 103 functions as an anode line. The other of the source electrode and the drain electrode of the transistor 103 is electrically connected to the wiring 47. The gate of the transistor 103 is electrically connected to one electrode of the light-emitting element 41. The gate electrode is connected to the other of the source electrode and the drain electrode of the transistor 43 and the capacitance element 10. 5 is electrically connected to one electrode of the

[0049] The transistor 103 is turned on or off to allow current to flow to the light emitting element 41. It has the function of controlling the current.

[0050] One of the source and drain electrodes of the transistor 45 is given a data reference potential. The other of the source electrode and the drain electrode of the transistor 45 is connected to the wiring 49. The first electrode of the capacitor 41 and the second electrode of the capacitor 105 are electrically connected to each other. The gate electrode of the transistor 45 is electrically connected to the scanning line 17 to which a gate signal is applied. can be.

[0051] The transistor 45 has a function of adjusting a current flowing through the light-emitting element 41. When the internal resistance of the light emitting element 41 increases due to deterioration of the element 41, the transistor 45 The current flowing through the wiring 49 to which one of the source electrode and the drain electrode is connected is monitored. By this, the current flowing through the light emitting element 41 can be corrected. The potential can be, for example, 0V.

[0052] One of a pair of electrodes of the capacitor 105 is a source electrode and a drain electrode of the transistor 43. The other of the two gate electrodes is electrically connected to the gate electrode of the transistor 103. The other of the pair of electrodes is connected to the other of the source electrode and drain electrode of the transistor 45 and the light emitting element The terminal 41 is electrically connected to one electrode of the terminal 41.

[0053] In the configuration of the subpixel 301 shown in FIG. 27(B), the capacitor element 105 The capacitor functions as a storage capacitor to store data.

[0054] One of the pair of electrodes of the light emitting element 41 is a source electrode and a drain electrode of the transistor 45. On the other hand, the other of the pair of electrodes of the capacitor 105 and the source and drain electrodes of the transistor 103 The other of the pair of electrodes of the light emitting element 41 is electrically connected to the other of the pair of electrodes of the light emitting element 41. It is electrically connected to a wiring 50 which functions as a cathode line.

[0055] The light-emitting element 41 is, for example, an organic electroluminescence element (also called an organic EL element). However, the light-emitting element 41 is not limited to this, and inorganic materials can be used. An inorganic EL element made of a material may also be used.

[0056] A high power supply potential VDD is applied to one of the wiring 47 and the wiring 50, and a low power supply potential VDD is applied to the other. In the configuration shown in FIG. 27B, a high power supply potential VSS is applied to the wiring 47. The power supply potential VSS is applied to the wiring 50 and the low power supply potential VSS is applied to the wiring 50.

[0057] In the display device having the sub-pixel 301 of FIG. 27B, the sub-pixels of each row are The pixels 301 are selected in sequence, the transistors 43 are turned on, and data of the data signal is written. Enter.

[0058] The sub-pixel 301 to which the data has been written is in a holding state by turning off the transistor 43. Furthermore, since the transistor 43 is connected to the capacitor 105, The data stored in the memory can be held for a long time. The amount of current flowing between the source electrode and the drain electrode is controlled, and the light emitting element 41 is turned on according to the amount of current flowing. By performing this process row by row, an image can be displayed.

[0059] In addition, in FIG. 27(A) and FIG. 27(B), a liquid crystal element 31 and a light emitting element 4 are used as display elements. 1 is used as an example, but one aspect of the embodiment of the present invention is not limited to this. It is also possible to use a display element. For example, an EL (electroluminescence) element ( EL elements, including organic and inorganic materials, organic EL elements, inorganic EL elements), LEDs (white LEDs, Red LED, green LED, blue LED, etc.), transistors (transistors that emit light according to the current Transistors), electron emission elements, liquid crystal elements, electronic ink, electrophoretic elements, grating lights Glow-light valves (GLV), plasma displays (PDP), MEMS (micro-electromechanical systems) Display element using digital micromirror device (DM D), DMS (Digital Micro Shutter), IMOD (Interference Modulation Modulation) modulation element, shutter-type MEMS display element, optical interference-type MEMS display Display element, electrowetting element, piezoelectric ceramic display, carbon nanotube Tubes, etc., change in contrast, brightness, reflectance, transmittance, etc. due to electromagnetic effects. An example of a display device using an EL element is an EL display. An example of a display device using electron emission elements is the field emitter. Flat-panel display (FED) or flat-panel display (SED:Surface ce-conduction Electron-emitter Display) An example of a display device using liquid crystal elements is a liquid crystal display (transmission type liquid crystal display). LCD, semi-transmissive LCD, reflective LCD, direct-view LCD Display using electronic ink or electrophoretic elements. An example of such a device is electronic paper. In order to realize a liquid crystal display, a part or all of the pixel electrodes are made to be 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 thickness of 100 nm or 100 nm. It is also possible to provide a memory circuit such as RAM, which further reduces power consumption. It is possible.

[0060] Next, FIG. 1(B) shows the circuit configuration described in FIG. 27(A) adapted to the layout of FIG. 1(A). An example of the circuit configuration when using this is shown below.

[0061] In FIG. 1B, pixel 13 is a pixel in the m-th row (m is a natural number), and pixel 13_1 ( The pixel 13_2 is shown as the pixel in the (m+1)th row.

[0062] The pixel 13_1 has a sub-pixel 14R_1 for controlling the transmission of R light, a sub-pixel 14R_2 for controlling the transmission of G light, and A pixel 14G_1, a sub-pixel 14B_1 for controlling the transmission of B light, and a sub-pixel 14B_2 for controlling the transmission of W light The pixel 13_2 has a sub-pixel 14R that controls the transmission of R light. _2, a sub-pixel 14 that controls the transmission of G light, G_2, a sub-pixel 14B that controls the transmission of B light The pixel 14 has a sub-pixel 14W_2 that controls the transmission of light W.

[0063] The subpixels 14R_1 and 14R_2 may be referred to as first subpixels. The subpixels 4G_1 and 14G_2 may be referred to as second subpixels. The subpixels 14W_1 and 14W_2 are sometimes referred to as a third subpixel. , and is sometimes called the fourth subpixel.

[0064] The sub-pixels 14R_1 to 14W_2 included in the pixel 13_1 and the pixel 13_2 are respectively The pixel includes a transistor 103 , a capacitor 105 , and a liquid crystal element 31 .

[0065] In FIG. 1B, the scanning line 17 is the Mth scanning line (M is a natural number). 7_1, as the (M+1)th scan line; 17_2, as the (M+2)th scan line Scan line 17_3 is shown.

[0066] In FIG. 1B, the signal line 25 is the signal line in the nth column (n is a natural number). 5_1, as the signal line for the (n+1)th column; signal line 25_2, as the signal line for the (n+2)th column The signal line 25_3 is shown.

[0067] The subpixel 14R may be referred to as a first subpixel. The subpixel 14G may be referred to as a second subpixel. The subpixel 14B may be referred to as the third subpixel. 14W is sometimes called the fourth subpixel.

[0068] The first gate line, which is also the gate electrode, is set to select three of the four subpixels. The second gate line selects the remaining subpixels and one subpixel in the next row. Connect to select.

[0069] The sub-pixels 14R_1 and 14R_2 in the pixels 13_1 and 13_2 are shown in FIG. By arranging the signal lines in this way, the number of signal lines is reduced to 100, making it possible to reduce the number of signal lines in a pixel having RGB sub-pixels arranged in stripes. In addition, the number of scanning lines can be increased to three for two pixels. It can be kept to the inspection line.

[0070] For example, if the display device is a liquid crystal display device, the four sub-pixels of RGBW are arranged in a stripe pattern. In this case, there are four data lines, one scanning line, and one capacitance line, for a total of six wires. Although it is possible to control it using this, the number of signal lines increases.

[0071] In addition, when the four RGBW sub-pixels are arranged in two rows and two columns, there are two data lines and two scan lines. Although it can be controlled using a total of five wires, the number of scanning lines is two and the number of capacitance lines is one. In this case, the circuit configuration of the scanning line driving circuit 12 becomes large. This makes it difficult to narrow the frame of the display device.

[0072] On the other hand, in a configuration disclosed in one aspect of the present invention, the pixels 13_1 and 13_2 arranged in two rows are The sub-pixels 14R_1 to 14W_2 can be driven by three scanning lines. In the configuration disclosed in one embodiment of the present invention, a signal line in which three sub-pixels of RGB are arranged in stripes is Therefore, the number of signal lines is smaller than when the four RGBW sub-pixels are arranged in stripes. Therefore, the number of the circuits can be reduced, particularly by making the circuit configuration of the scanning line driving circuit 12 smaller. Therefore, it is possible to realize a narrower frame of the display device.

[0073] Next, FIG. 28A shows a cross section of a transistor 103 and a capacitor 105 included in a display device. The figure is shown.

[0074] The transistor 103 shown in FIG. 28A has a gate electrode provided over a substrate 302. A functional conductive film 304c, and a gate insulating film formed on the substrate 302 and the conductive film 304c. 51, and an oxide semiconductor film 308b overlapping with the conductive film 304c with the gate insulating film 51 interposed therebetween. A pair of electrodes functioning as a source electrode and a drain electrode in contact with the oxide semiconductor film 308b The conductive film 310d and the conductive film 310e are provided.

[0075] In addition, a metal oxide film 308c is provided on the gate insulating film 51. The film 308c is connected to one of a pair of conductive films 310e included in the transistor 103. In addition, an inorganic insulating film 53 is provided on the transistor 103 and the metal oxide film 308c. A conductive film 316b is provided on the inorganic insulating film 53. A metal oxide film 308c, The inorganic insulating film 53 and the conductive film 316b form the capacitor element 105.

[0076] In addition, an organic insulating film 317 is provided on the inorganic insulating film 53 and the conductive film 316b. In the openings provided in the inorganic insulating film 53 and the organic insulating film 317, the conductive film 310e and A conductive film 319 is provided on the organic insulating film 317. The conductive film 319 is a pixel electrode. It functions as:

[0077] The metal oxide film 308c is an oxide semiconductor film formed at the same time as the oxide semiconductor film 308b. , hydrogen, boron, phosphorus, nitrogen, tin, antimony, rare gas elements, alkali metals, alkali By adding impurities such as earth metals and creating oxygen deficiencies, the electrical conductivity is improved. Note that since the oxide semiconductor film has a light-transmitting property, the metal oxide film 308c It has light-transmitting properties.

[0078] In an oxide semiconductor with oxygen vacancies, hydrogen enters the oxygen vacancy sites, and the 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 called an oxide conductor. In general, 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 having a donor level near the conduction band. Therefore, the effect of absorption due to the donor level is small, and the oxide semiconductor has a high It has the same degree of translucency as that of

[0079] The conductive film 316b and the conductive film 319 are formed using a light-transmitting conductive film. Therefore, the area of ​​the capacitor in the pixel is large. It is possible to increase the capacitance of the capacitive element and the aperture ratio of the pixel.

[0080] The inorganic insulating film 53 includes at least an oxide insulating film, and further includes an oxide insulating film and a nitride insulating film. In the inorganic insulating film 53, the oxide semiconductor film 308 is preferably laminated. In the region in contact with the oxide semiconductor film 308b, an oxide insulating film is formed. The amount of defects at the interface with the inorganic insulating film 53 can be reduced.

[0081] The nitride insulating film functions as a barrier film against water, hydrogen, and the like. When water, hydrogen, or the like is contained in the oxide semiconductor film 308b, the water, hydrogen, or the like is mixed with oxygen contained in the oxide semiconductor film 308b. The reaction occurs, and oxygen vacancies are formed. carriers are generated, the threshold voltage of the transistor is shifted negatively, and the normally-on Therefore, by providing a nitride insulating film on the inorganic insulating film 53, The amount of diffusion of water, hydrogen, and the like from the oxide semiconductor film 308b to the oxide semiconductor film 308b can be reduced. Therefore, the amount of defects in the inorganic insulating film 53 can be reduced. In this case, an oxide insulating film and a nitride insulating film are stacked in this order from the oxide semiconductor film 308b side. As a result, the number of defects at the interface between the oxide semiconductor film 308b and the inorganic insulating film 53 and the amount of oxygen It is possible to reduce the amount of oxygen vacancies in the oxide semiconductor film 308b. It is possible to fabricate transistors with the following characteristics.

[0082] The organic insulating film 317 is made of an organic resin such as an acrylic resin, a polyimide resin, or an epoxy resin. The thickness of the organic insulating film 317 is 500 nm or more and 5000 nm or less. nm or less, preferably 1000 nm or more and 3000 nm or less.

[0083] In addition, the conductive film 319 formed on the organic insulating film 317 is connected to the transistor 103. The conductive film 319 functions as a pixel electrode and is provided on the inorganic insulating film 53 and the organic insulating film 317. That is, the conductive film 319 is connected to the transistor 103 through the opening. Since the distance between the conductive film 310d and the transistor 103 is large, the potential of the conductive film 310d of the transistor 103 is not affected. As a result, the conductive film 319 can overlap with the transistor 103. Therefore, the aperture ratio of the pixel can be increased.

[0084] As a comparative example, a transistor in which the organic insulating film 317 is not formed on the inorganic insulating film 53 is In a display device having the transistor 103, a conductive film that functions as a gate electrode of the transistor 103 The case where a negative voltage is applied to the film 304c will be described.

[0085] When a negative voltage is applied to the conductive film 304c functioning as a gate electrode, an electric field is generated. The electric field is not blocked by the oxide semiconductor film 308b and affects the inorganic insulating film 53. A weak positive charge is applied to the surface of the inorganic insulating film 53. Also, a conductive film that functions as a gate electrode When a negative voltage is applied to the film 304c, positively charged particles contained in the air are charged to the inorganic insulating film 53. The surface of the inorganic insulating film 53 is then charged with a weak positive charge.

[0086] The surface of the inorganic insulating film 53 is positively charged, generating an electric field, which is then applied to the oxide semiconductor. This affects the interface between the conductive film 308b and the inorganic insulating film 53. As a result, the oxide semiconductor film 30 A positive bias is substantially applied to the interface between the insulating film 8b and the inorganic insulating film 53. , the threshold voltage of the transistor is shifted negatively.

[0087] On the other hand, the transistor 103 shown in FIG. 28A has an organic insulating film 317 on an inorganic insulating film 53. Since the organic insulating film 317 is thick, it is not negatively affected by the conductive film 304c that functions as the gate electrode. The effect of the electric field generated by applying the voltage is reflected on the surface of the organic insulating film 317. Therefore, the surface of the organic insulating film 317 is not easily charged with positive charges. Even if the charged particles are adsorbed on the surface of the organic insulating film 317, the organic insulating film 317 is thick and the charged particles are not adsorbed. The electric field of the positively charged particles adsorbed on the surface of the organic insulating film 317 is generated in the oxide semiconductor film 308b and the inorganic insulating film 317. As a result, the oxide semiconductor film 308b and the inorganic insulating film 53 are not easily affected. At the interface of the insulating film 53, a positive bias is not substantially applied, and the transistor The variation in threshold voltage of the transistor is small.

[0088] In addition, water and the like are likely to diffuse in the organic insulating film 317, but the inorganic insulating film 53 is a nitride insulating film. By having the film, the nitride insulating film acts as a barrier film for water, and the water diffused into the organic insulating film 317 is prevented from entering the nitride insulating film. It is possible to prevent the diffusion of the oxide semiconductor film 308b into the oxide semiconductor film 308b.

[0089] From the above, by providing the organic insulating film 317 on the transistor, the electric potential of the transistor can be reduced. It is possible to reduce the variation in thermal characteristics. In addition, it has normally-off characteristics and is highly reliable. In addition, the organic insulating film can be formed by a printing method, a coating method, etc. Since the film can be formed using the above method, the manufacturing time can be shortened. By providing a conductive film that functions as a pixel electrode on the organic insulating film 317, an opening in the pixel The rate can be increased.

[0090] <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 The films formed from oxide conductors (hereinafter referred to as oxide conductor films (OC)) The temperature dependence of resistivity will be explained with reference to FIG. 29. In FIG. 29, the horizontal axis indicates the measured The vertical axis indicates the temperature, and the vertical axis indicates the resistivity. The measurement results of the oxide semiconductor film (OS) are indicated by circles. The measurement results for oxide conductor films (OC) are indicated by square marks.

[0091] Note that the sample including the oxide semiconductor film (OS) was prepared by depositing a semiconductor layer 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: A 20 nm thick In-GaAs thin film was deposited by sputtering using the No. 5 sputtering target. A Zn oxide film was formed, and the film was then heat-treated in a nitrogen atmosphere at 450°C. The silicon oxynitride film is then formed by plasma CVD. Formed and produced.

[0092] The sample containing the oxide conductor (OC) was prepared by depositing a layer 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, The material is heated at 450℃ in a nitrogen and oxygen mixed gas atmosphere, and then silicon nitride is formed by plasma CVD. It was fabricated by forming a silicon film.

[0093] As can be seen from FIG. 29, the temperature dependence of resistivity in the oxide conductor film (OC) is The temperature dependence of resistivity is smaller than that of the OSC film. The rate of change in resistivity of the oxide conductor film (OC) at 90K or less is less than ±20%. Alternatively, the rate of change in resistivity from 150K to 250K is less than ±10%. That is, the oxide conductor is a degenerate semiconductor, and the conduction band edge and the Fermi level coincide or almost coincide. For this reason, oxide conductor films are used for wiring, electrodes, pixel electrodes, etc. It is possible. <Variation 1>

[0094] A modification of the transistor shown in FIG. 28(A) will be described with reference to FIG. The transistor 103c in the modification has an oxide semiconductor film formed using a multi-tone mask. The transistor is characterized by having a pair of conductive films 310f and 310g. The transistor 103c and the capacitor element 105 are connected to each other through a conductive film 319 that functions as a pixel electrode. It is characterized by the fact that

[0095] By using a multi-tone mask, it is possible to form resist masks with multiple thicknesses. After the oxide semiconductor film 308e is formed using the resist mask, oxygen plasma By exposing the resist mask to light, a part of the resist mask is removed to form a pair of conductive films. Therefore, the oxide semiconductor film 308e and the pair of conductive films The number of photolithography steps in the process of forming the films 310f and 310g can be reduced. Cut.

[0096] Note that part of the oxide semiconductor film 308e formed using the multi-tone mask has a planar shape 310f, 310g, and is covered by the pair of conductive films 310f, 310g. That is, a part of the oxide semiconductor film 308e is not overlapped with the pair of conductive films 310f and 31 It is exposed outside 0g.

[0097] In addition, in FIG. 28(B), a metal oxide film 308f is formed on the gate insulating film 51. In addition, a conductive film 310h is formed on the metal oxide film 308f at the same time as the conductive films 310f and 310g. In addition, the conductive film 319 is connected to the conductive film 310g and the conductive film 310h. As a result, the transistor 103c and the capacitor 105 are electrically connected to each other.

[0098] <Variation 2> A modification of the transistor shown in FIG. 28(A) will be described with reference to FIG. The transistor 103d shown in the modification is a transistor formed with a channel protection structure. It is characterized by the above.

[0099] The transistor 103d having the channel protection structure has an opening in the insulating film 53a. The oxide semiconductor film 308b and the pair of conductive films 310i and 310j are connected to each other. With this shape, damage to the oxide semiconductor film 308b can be reduced.

[0100] <Variation 3> In the display devices shown in FIGS. 28(A) to 28(C), depending on circumstances or circumstances, For example, the conductive film 319 may be formed using a conductive film having a function of reflecting light. Alternatively, the conductive film 319 may be formed using a laminated film, and at least one of the laminated films may be A conductive film having a function of reflecting light may be used as the film. Examples of the material of the conductive film include silver, aluminum, chromium, copper, tantalum, titanium, and molybdenum. Alternatively, silver may be used as the conductive film 319. Alternatively, a laminated film may be formed by sandwiching a film formed by the above method and the below method with ITO. In such cases, reflective display devices, semi-transmissive display devices, top-emission light-emitting devices, etc. The display devices shown in FIGS. 28A to 28C can be applied to such applications.

[0101] In the display device according to one embodiment of the present invention described above, the first subpixel having the first to fourth subpixels a second pixel having a first pixel and first to fourth sub-pixels provided in a row next to the first pixel; In the configuration having the above, a signal for selecting the first to third sub-pixels of the first pixel is a first wiring for providing a fourth sub-pixel of the first pixel; and a second wiring for selecting a fourth sub-pixel of the first pixel. , and the second wiring is a wiring for selecting a fourth sub-pixel included in the second pixel. , and the configuration is as follows.

[0102] Therefore, the number of signal lines is the same as the number of signal lines that form the stripe arrangement of the three RGB sub-pixels. At the same time, the number of scanning lines per two rows of pixels can be reduced to three. Therefore, the circuit configuration of the scanning line driving circuit 12 can be made smaller. A narrower frame can be achieved.

[0103] In addition, in the display device according to one embodiment of the present invention, the capacitor has a light-transmitting property. Therefore, it is possible to form a large capacitance element (large area). Generally speaking, it is possible to set the capacity at 50% or more, preferably 60% or more, and at the same time, to increase the capacity value. For example, a display device with high resolution, such as a liquid crystal display, can be obtained. In the device, the area of ​​the pixel is reduced, and the area of ​​the capacitance element is also reduced. In a display device with a high image quality, the amount of charge stored in the capacitance element is small. Since the capacitor 105 shown in this embodiment has a light-transmitting property, the capacitor is provided in a pixel. This makes it possible to increase the aperture ratio while obtaining a sufficient capacitance value in each pixel.

[0104] In addition, in a liquid crystal display device, the larger the capacitance of the capacitance element, the greater the capacitance of the capacitance element. By using the liquid crystal display, 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, reducing the number of times the image data is rewritten. It is possible to reduce the power consumption. This structure allows the aperture ratio to be increased even in high-resolution display devices, It is possible to efficiently use light from light sources such as ceiling lamps, thereby reducing the power consumption of display devices. It is possible.

[0105] The pixels are divided into four types: R subpixels, G subpixels, B subpixels, and W subpixels. However, one embodiment of the present invention is not limited to this. It is sufficient that the pixel has at least a plurality of sub-pixels among the four types of sub-pixels. The sub-pixels included in each pixel may differ depending on the pixel.

[0106] For example, a first pixel has an R subpixel, a G subpixel, and a B subpixel, and a second pixel has an R Alternatively, the first pixel may have a subpixel of R, a subpixel of G, and a subpixel of W. , G sub-pixels, and the second pixel may have B and W sub-pixels. The first pixel has an R subpixel, a G subpixel, and a B subpixel, and the second pixel has an R subpixel. , a G subpixel, a B subpixel, and a W subpixel.

[0107] Note that the structures and methods described in this embodiment may be different from the structures and methods described in other embodiments. They can be used in appropriate combination.

[0108] (Embodiment 2) In this embodiment, a display device according to one embodiment of the present invention and a manufacturing method thereof will be specifically described. The following description will be given with reference to the drawings showing the configuration.

[0109] First, a specific configuration of an element substrate included in the display device will be described. A VA type liquid crystal display device is used as the liquid crystal display device, and sub-pixels 14R_1 and 14R_2 included in the liquid crystal display device are 4G_1, 14B_1, 14W_1, 14R_2, 14G_2, 14B_2, 14W_2 2 shows a top view of the subpixel 14 (hereinafter referred to as subpixel 14). FIG. 3 is a top view showing the arrangement of the members on the element substrate side shown in FIG. 2 and 3 are top views showing the arrangement of members on the opposing substrate side, which correspond to the side views shown in FIG. 1(B) is a top view corresponding to the circuit configuration shown in FIG.

[0110] In FIG. 2, the conductors functioning as scanning lines for the sub-pixels 14R_1, 14G_1, and 14B_1 are The conductive film 304c and the conductive film 304d functioning as the scanning lines of 14W_1 and 14W_2 are The conductive film functions as a signal line, and extends in a direction substantially perpendicular to the conductive film (left and right direction in the drawing). The conductive film 310d functioning as a signal line is substantially perpendicular to the conductive film functioning as a scanning line. The conductive film that functions as the scanning line is provided so as to extend in the direction in which the scanning line is formed (the vertical direction in the drawing). 304c is electrically connected to the scanning line driving circuit 12 (see FIG. 1(A)) and The conductive film 310d functioning as a signal line is connected to the signal line driver circuit 16 (see FIG. 1A). are electrically connected.

[0111] The transistor 103 has a conductive film functioning as a scan line and a conductive film functioning as a signal line. The transistor 103 is provided in the intersecting region. A film 304c, a gate insulating film (not shown in FIG. 2), and a channel formed on the gate insulating film. The oxide semiconductor film 308b in which the regions are formed functions as a source electrode and a drain electrode. The conductive film 304c is a pair of conductive films 310d and 310e. The region overlapping with the oxide semiconductor film 308b also functions as a conductive film. The conductive film 310d functions as a gate electrode of the gate electrode 103. The oxide semiconductor film 308b also functions as a conductive film for the transistor 103. In FIG. 2, the gate electrode functions as a scanning line. The conductive film has an end portion located outside an end portion of the oxide semiconductor film 308b in a top view. For this reason, the conductive film that functions as the scanning line blocks light from a light source such as a backlight. As a result, the oxide semiconductor film 308b included in the transistor is shielded from light. Therefore, the change in the electrical characteristics of the transistor can be suppressed.

[0112] The metal oxide film 308c is connected to the conductive film 310e included in the transistor 103. In addition, a conductive film 316b is provided over the metal oxide film 308c with an insulating film interposed therebetween. In addition, an opening 362 is formed in the insulating film provided on the metal oxide film 308c. In the opening 362, the metal oxide film 308c is included in the insulating film. It is in contact with a nitride insulating film (not shown in FIG. 2).

[0113] The capacitor 105 is formed in a region where the metal oxide film 308c and the conductive film 316b overlap each other. The metal oxide film 308c and the conductive film 316b have a light-transmitting property. has light-transmitting properties.

[0114] The conductive film 319 functioning as a pixel electrode is connected via an organic insulating film (not shown in FIG. 2). The conductive film 319 is provided on the conductive film 310e and the conductive film 316b. 4c is connected to the conductive film 310e. 5 and the conductive film 319 are electrically connected.

[0115] Since the capacitance element 105 has a light-transmitting property, the capacitance element 105 can be made large (large surface area) within the sub-pixel 14. Therefore, it is possible to increase the aperture ratio, typically 50% or more, and It is possible to obtain a display device having an increased capacitance value, while increasing the capacitance to 60% or more. For example, in a high-resolution display device, such as a liquid crystal display device, the pixel surface Therefore, the capacitance element area is small. Therefore, the amount of charge stored in the capacitance element is reduced. Since the element 105 has a light-transmitting property, by providing the capacitor element in the pixel, It is possible to increase the aperture ratio while obtaining a sufficient capacitance value. Typically, the pixel density is 200p pi or higher, even 300ppi or higher, or even 500ppi or higher. The present invention can be suitably used in such a case.

[0116] In addition, in a liquid crystal display device, the larger the capacitance value of the capacitance element, the more In the liquid crystal display device, 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, reducing the frequency with which image data is rewritten. It is possible to reduce the number of circuits, and therefore the power consumption. The structure shown in FIG. 1 can increase the aperture ratio even in a high-resolution display device. It is possible to efficiently use light from light sources such as backlights, thereby reducing the power consumption of display devices. It is possible.

[0117] In addition, in a top view of the counter substrate side shown in FIG. 3, which corresponds to the top view of FIG. 2, an example of the arrangement of the sub-pixels 14 is shown. In the subpixel 14, the color film R1, G1, B1, a light-transmitting layer W1, a colored film R2, G2, B2, and a light-transmitting layer W2 It is provided.

[0118] The light-shielding film BM may be a metal film, as long as it has a function of blocking light in a specific wavelength range. Alternatively, an organic insulating film containing a black pigment or the like can be used.

[0119] The colored films R1, G1, B1, R2, G2, and B2 convert the light from the light source that passes through them into light of a specified color. Typically, a color filter is used to select the corresponding RGB subpixels. , may be disposed in the sub-pixel.

[0120] The light-transmitting layers W1 and W2 are layers for transmitting light from a light source. Using organic resins such as acrylic resin, polyimide, and epoxy resin, It is sufficient to dispose the light-transmitting layers W1 and W2 in the pixels. Alternatively, a layer that absorbs light of a specific wavelength is provided as a layer having the light-transmitting layers W1 and W2. In this case, for example, a suitable white color can be obtained depending on the wavelength of the light from the light source. Even if the monitor is not fully illuminated, the white balance can be adjusted to achieve high color purity. can.

[0121] Next, a cross-sectional view taken along line CD in FIG. 2 and FIG. 3 is shown in FIG. 1, a driving circuit section including the scanning line driving circuit 12 and the signal line driving circuit 16 (a top view is omitted). In the present embodiment, a VA type display device is used as the display device. A liquid crystal display device of the above type will now be described.

[0122] The liquid crystal display device shown in this embodiment has a liquid crystal display device between a pair of substrates (a substrate 302 and a substrate 342). The child 322 is clamped.

[0123] The liquid crystal element 322 is made of a conductive film 319 on the substrate 302 and a film for controlling the orientation (hereinafter, the The liquid crystal display device has a liquid crystal layer 321 and a conductive film 350. The conductive film 319 functions as one electrode of the liquid crystal element 322, and the conductive film 350 functions as one electrode of the liquid crystal element 322. 22 serves as the other electrode.

[0124] Thus, a liquid crystal display device is a device having a liquid crystal element. The liquid crystal display device includes a driving circuit for driving a plurality of pixels. The liquid crystal display includes a control circuit, a power supply circuit, a signal generating circuit, a backlight module, etc. It is also called a crystal module.

[0125] In the driving circuit section, a conductive film 304a functioning as a gate electrode and a gate insulating film 51 are formed. The insulating film 305 and the insulating film 306 functioning as a channel region are formed in the oxide semiconductor film 3. 08a, the conductive films 310a and 310b functioning as source and drain electrodes are The oxide semiconductor film 308a constitutes the transistor 102. The oxide semiconductor film 308a is provided on the gate insulating film 51. can be.

[0126] In the pixel portion, a conductive film 304c functions as a gate electrode, and a gate insulating film 51 functions as a gate insulating film. The channel region formed on the insulating film 305 and the insulating film 306 and the gate insulating film 51 is The oxide semiconductor film 308b formed and the conductive film functioning as a source electrode and a drain electrode The oxide semiconductor film 308b includes the oxide semiconductor film 310d and the oxide semiconductor film 310e. The gate insulating film 51 is provided on the conductive films 310d and 310e. An insulating film 312 and an insulating film 314, which are referenced 53, are provided as protective films.

[0127] In addition, a metal oxide film 308c which functions as one electrode and an insulating film which functions as a dielectric film The capacitor 105 is formed by the conductive film 314 and the conductive film 316b functioning as the other electrode. The metal oxide film 308c is provided on the gate insulating film 51.

[0128] An organic insulating film 317 is formed on the inorganic insulating film 53. A conductive film 319 that functions as a base electrode is formed. The conductive film 319 is connected to the conductive film 310e. To be continued.

[0129] In the driving circuit section, the conductive film 304 is formed simultaneously with the conductive films 304a and 304c. b and the conductive film 310 formed simultaneously with the conductive films 310a, 310b, 310d, and 310e. The conductive film 319a is formed at the same time as the conductive film 319, and the conductive film 319c is connected to the conductive film 319a.

[0130] The conductive film 304b and the conductive film 319a are formed by the insulating film 305, the insulating film 306, the insulating film 312, and the insulating film 319b. The insulating film 314 and the organic insulating film 317 are connected to each other through openings formed therein. The insulating film 310c and the conductive film 319a are provided on the insulating film 312, the insulating film 314, and the organic insulating film 317. The connection is made at the opening provided.

[0131] Although not shown, the conductive film 316b is a conductive film formed at the same time as the conductive films 319 and 319a. The conductive film may be a conductive film formed at the same time as the conductive films 304a, 304b, and 304c, or a conductive film. The conductive films 310a, 310b, 310c, 310d, and 310e are formed simultaneously with the conductive films. In addition, the conductive films 304a, 304b, and 304c are formed at the same time. , or formed simultaneously with the conductive films 310a, 310b, 310c, 310d, and 310e Any potential, such as a common potential or a ground potential, is applied to the conductive film 316b via the conductive film.

[0132] Here, the components of the display device shown in FIG. 4 will be described below.

[0133] Conductive films 304a, 304b, and 304c are formed on the substrate 302. The conductive film 4a functions as a gate electrode of a transistor in the driving circuit section. 04b is formed in the driving circuit section and is connected to the conductive film 310c. , which is formed in the pixel section 11 and functions as a gate electrode of a transistor in the pixel section.

[0134] There is no particular restriction on the material of the substrate 302, but it should be at least strong enough to withstand the subsequent heat treatment. It is necessary to have heat resistance. For example, glass substrate, ceramic substrate, quartz substrate, surface treatment substrate, etc. A fiber substrate or the like may be used as the substrate 302. Also, silicon or silicon carbide may be used as the material. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, and compound semiconductor substrates such as silicon germanium It is also possible to use a substrate, an SOI substrate, or the like, on which a semiconductor element is provided. The substrate 302 may be a glass substrate. In this case, 6th generation (1500mm x 1850mm), 7th generation (1870mm x 2200 mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 2800 By using large area substrates such as 10th generation (2950mm x 3400mm), It is possible to manufacture a liquid crystal display device of this type.

[0135] In addition, a flexible substrate is used as the substrate 302, and a transistor is formed directly on the flexible substrate. Alternatively, a peeling layer may be provided between the substrate 302 and the transistor. After completing a part or the whole of the element part on it, it is separated from the substrate 302 and attached to another substrate. In this case, the transistors are mounted on substrates with poor heat resistance or flexible substrates. It can also be transferred to a circuit board.

[0136] The conductive films 304a, 304b, and 304c may be made of aluminum, chromium, copper, tantalum, A metal element selected from titanium, molybdenum, and tungsten, or a metal element composed of the above-mentioned metal elements. The metal element may be an alloy having the above-mentioned metal elements or an alloy combining the above-mentioned metal elements. In addition, the present invention uses a metal element selected from one or more of manganese and zirconium. The conductive films 304a, 304b, and 304c may have a single-layer structure or a laminate of two or more layers. For example, a single layer structure of an aluminum film containing silicon, A two-layer structure in which a titanium film is laminated on a titanium nitride film, a two-layer structure in which a titanium film is laminated on a titanium nitride film, A two-layer structure in which a tungsten film is laminated on a titanium nitride film, a tantalum nitride film or a tungsten nitride film A two-layer structure in which a tungsten film is laminated on a titanium film, and an aluminum film is laminated on the titanium film. There are three-layer structures, such as a laminated aluminum film and a titanium film on top of that. Aluminum, titanium, tantalum, tungsten, molybdenum, chromium, neodymium, scandium Alternatively, an alloy film made by combining one or more of the above materials or a nitride film may be used.

[0137] The conductive films 304a, 304b, and 304c are made of indium tin oxide or tungsten oxide. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide, titanium oxide, indium tin oxide, indium zinc oxide, By using a conductive material having light transmission properties such as indium tin oxide with added silicon oxide, In addition, the conductive material having the light-transmitting property and the metal element may be laminated to form a laminate structure. It is also possible.

[0138] An insulating film 305 and an insulating film 306 are formed on the substrate 302 and the conductive films 304a, 304c, and 304b. The insulating film 305 and the insulating film 306 are formed on the gate of the transistor in the driving circuit section. The gate insulating film 51 functions as the gate insulating film 51 of the transistor in the pixel section 11. do.

[0139] The insulating film 305 may be, for example, silicon nitride, silicon oxynitride, aluminum nitride, or nitride. It is preferable to form the insulating film using a nitride such as aluminum oxide.

[0140] The insulating film 306 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. Silicon oxide, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn metal An oxide or the like may be used, and may be formed as a laminated layer or a single layer. HfSiO x ), nitrogen-doped hafnium silicate (HfS i x O y N z ), nitrogen-doped hafnium aluminate (HfAl x O y N z ),acid By using high-k materials such as hafnium oxide and yttrium oxide, Gate leakage can be reduced.

[0141] The total thickness of the insulating film 305 and the insulating film 306 is preferably 5 nm or more and 400 nm or less. The thickness is preferably 10 nm or more and 300 nm or less, and more preferably 50 nm or more and 250 nm or less. good.

[0142] Oxide semiconductor films 308a and 308b and a metal oxide film 308c are formed over the insulating film 306. The oxide semiconductor film 308a is formed in a position overlapping with the conductive film 304a. The oxide semiconductor film 308b functions as a channel region of a transistor in the operating circuit portion. The conductive film 304c is formed in a position overlapping the conductive film 304c, and serves as a channel region of a transistor in a pixel portion. The metal oxide film 308c functions as a conductive film 310e included in the transistor 103. and serves as an electrode of the capacitor 105.

[0143] The oxide semiconductor films 308a and 308b and the metal oxide film 308c are typically In- Ga oxide, In-Zn oxide, In-M-Zn oxide (M is Al, Ti, Ga, Y, Z) The oxide semiconductor films 308a, 308b, 308c, 308d, 308e, 308f, 308g, 308h ... The metal oxide film 308b and the metal oxide film 308c have light-transmitting properties.

[0144] Note that the oxide semiconductor films 308a and 308b and the metal oxide film 308c are In-M-Zn When it is an oxide, the atomic ratio of In and M is 100 atomic %. In is 25 atomic % or more, and M is less than 75 atomic %, and more preferably In is preferably 34 atomic % or more and M is preferably less than 66 atomic %.

[0145] The oxide semiconductor films 308a and 308b and the metal oxide film 308c have an energy gap is 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. In addition, by using an oxide semiconductor with a wide energy gap, the off-state current of a transistor can be reduced. can be reduced.

[0146] The oxide semiconductor films 308a and 308b and the metal oxide film 308c have a thickness of 3 nm or more. 00 nm or less, preferably 3 nm or more and 100 nm or less, and more preferably 3 nm or more and 50 nm or less.

[0147] The oxide semiconductor films 308a and 308b and the metal oxide film 308c are made of In:Ga:Zn. In:Ga:Zn=1:1:1, In:Ga:Zn=1:1:1.2, or In with an atomic ratio of 3:1:2 The oxide semiconductor films 308a, 308b, and 308c can be formed of a Ga—Zn oxide. The atomic ratios of the metal oxide film 308c are determined by the above atomic ratios plus error. Includes a 20% fluctuation in ins.

[0148] The oxide semiconductor films 308a and 308b and the metal oxide film 308c are, for example, non-crystalline. The non-single crystal structure may be, for example, a CAAC-OS (C Axis A ligated Crystalline Oxide Semiconductor), This includes polycrystalline structures, microcrystalline structures (described later), and amorphous structures. The amorphous structure has the highest density of defect states, while the CAAC-OS has the lowest density of defect states. The oxide semiconductor films 308a and 308b and the metal oxide film 308c have the same crystallinity. .

[0149] Note that the oxide semiconductor films 308a and 308b and the metal oxide film 308c are amorphous. The regions are: microcrystalline structure, polycrystalline structure, CAAC-OS, single crystal structure. The mixed film may have two or more types of regions of the amorphous structure. region, microcrystalline region, polycrystalline region, CAAC-OS region, and single crystal region. In some cases, the mixed film has a single layer structure having two or more regions. The regions are: microcrystalline structure, polycrystalline structure, CAAC-OS, single crystal structure. The laminated structure may include two or more of the above-mentioned regions.

[0150] The oxide semiconductor films 308a and 308b contain silicon or carbon, which is one of the Group 14 elements. When the oxide semiconductor films 308a and 308b contain oxygen vacancies, the oxide semiconductor films 308a and 308b become n-type. As a result, the concentrations of silicon and carbon in the oxide semiconductor films 308a and 308b (concentration obtained by secondary ion mass spectrometry) is 2×10 18 atoms / cm 3 below , preferably 2 x 10 17 atoms / cm 3 The following applies.

[0151] In addition, the oxide semiconductor films 308a and 308b were analyzed by secondary ion mass spectrometry. The concentration of alkali metal or alkaline earth metal in 18 atoms / cm 3 below , preferably 2 x 10 16 atoms / cm 3 The following are alkali metals and alkaline earth metals: When metal oxides are bonded to oxide semiconductors, they can generate carriers, which can be used to form the on-state of transistors. Therefore, the current of the oxide semiconductor films 308a and 308b may increase. It is preferred to reduce the concentration of alkaline metals or alkaline earth metals.

[0152] In addition, when nitrogen is contained in the oxide semiconductor films 308a and 308b, the electrons serving as carriers This causes an increase in carrier density, making it easier to convert to n-type. A transistor using a semiconductor tends to be normally on. In the conductive film, it is preferable that the nitrogen is reduced as much as possible. For example, the nitrogen is reduced by secondary ions. The nitrogen concentration obtained by mass spectrometry is 5×10 18 atoms / cm 3 What to do below is preferred.

[0153] The oxide semiconductor films 308a and 308b are formed using oxide semiconductor films with low carrier density. For example, the oxide semiconductor films 308a and 308b have a carrier density of 1×10 17 / cm 3 Less than or equal to 1×10 15 / cm 3 Less than 1×10, more preferably 13 / cm 3 Below, particularly preferably 8 × 10 11 / cm 3 less than 1×10 11 / cm 3 less than 1×10 10 / cm 3 Less than 1 x 10 -9 / cm 3 End An oxide semiconductor film having a thickness of 100 nm to 150 nm is used.

[0154] In addition, the semiconductor characteristics and electrical characteristics (field effect The appropriate composition should be used depending on the required properties (mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of a transistor, the carrier Density, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. It is preferable to use the above-mentioned method.

[0155] The oxide semiconductor films 308a and 308b are formed by forming the oxide semiconductor film such as the insulating film 306 and the insulating film 312. The material is capable of improving the interface properties with the body membrane, so the material is in contact with the membrane, and oxidation The oxide semiconductor films 308a and 308b function as semiconductors. The transistor having 8b has excellent electrical characteristics.

[0156] Note that the oxide semiconductor films 308a and 308b have a low impurity concentration and a low density of defect states. By using a thin oxide semiconductor film, a transistor with excellent electrical characteristics can be manufactured. Here, the impurity concentration is low and the defect level density is low (there is little oxygen vacancy). ) is called high purity genuine or substantially high purity genuine. High purity genuine or substantially high purity Intrinsic oxide semiconductors have few carrier generation sources, so they can reduce the carrier density. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film may be formed. The transistor has electrical characteristics in which the threshold voltage is negative (also called normally on). In addition, the oxide semiconductor may be highly intrinsic or substantially highly intrinsic. The film has a low defect density and may also have a low trap density. An oxide semiconductor film that is intrinsic or substantially highly purified intrinsic has an extremely small off-state current and The width of the panel is 1×10 6 Even if the device has a channel length L of 10 μm, the source and drain electrodes When the voltage between the drain electrodes (drain voltage) is in the range of 1V to 10V, the off-state current is Below the measurement limit of the body parameter analyzer, i.e., 1 × 10 -13 Achieved a characteristic of A or lower Therefore, a transistor in which a channel region is formed in the oxide semiconductor film can be formed. In some cases, the change in electrical characteristics is small, resulting in a highly reliable transistor. Charges trapped in the trap levels of the semiconductor film take a long time to disappear. Therefore, the oxide semiconductor with high trap density may behave like a fixed charge. A transistor in which a channel region is formed in a conductive film may have unstable electrical characteristics. The impurities include hydrogen, nitrogen, alkali metals, and alkaline earth metals.

[0157] The metal oxide film 308c is an oxide semiconductor film formed at the same time as the oxide semiconductor films 308a and 308b. Therefore, the metal oxide film 308c is formed by processing the oxide semiconductor film 3 The oxide semiconductor films 308a and 308b each contain the same metal element. The film may have a similar crystal structure to 308b or a different crystal structure. The oxide semiconductor film formed simultaneously with the oxide semiconductor films 308a and 308b is treated with an impurity or an acid. By providing the elemental deficiency, the film becomes conductive and functions as an electrode of a capacitance element. The impurity contained in the oxide semiconductor film is hydrogen. Boron, phosphorus, tin, antimony, rare gas elements, alkali metals, alkaline earth metals The metal oxide film 308c may include the oxide semiconductor film 308a, This film was formed at the same time as 308b. Oxygen vacancies were formed due to plasma damage, etc. Alternatively, the metal oxide film 308c is a film having enhanced conductivity. A film formed at the same time as 308b, containing impurities and plasma damage. The film has oxygen vacancies due to the above-mentioned reasons, and has increased electrical conductivity.

[0158] Therefore, the oxide semiconductor films 308a and 308b and the metal oxide film 308c are insulating films. Specifically, the oxide semiconductor film 308a is formed over the oxide semiconductor film 306, but has a different impurity concentration. The impurity concentration of the metal oxide film 308c is higher than that of the metal oxide film 308b. The hydrogen concentration in the films 308a and 308b is 5×10 19 atoms / cm 3 Less than, good Preferably 5 x 10 18 atoms / cm 3 Less than 1 x 10 18 atoms / c m 3 Less than or equal to 5×10 17 atoms / cm 3 Below, more preferably 1× 10 16 atoms / cm 3 The hydrogen concentration in the metal oxide film 308c is 8×10 19 atoms / cm 3 More than 1×10 20 atoms / cm 3 End , more preferably 5 × 10 20 atoms / cm 3 The above is the case. In addition, the oxide semiconductor film 3 The hydrogen concentration in the metal oxide film 308c is preferably twice as high as that in the metal oxide film 308a and 308b. In most cases, it is more than 10 times higher.

[0159] In addition, the oxide semiconductor film formed at the same time as the oxide semiconductor films 308a and 308b is The oxide semiconductor film can be damaged by exposure to oxygen, and oxygen vacancies can be formed. For example, a film is formed on an oxide semiconductor film by a plasma CVD method or a sputtering method. When the oxide semiconductor film is heated, the oxide semiconductor film is exposed to plasma, and oxygen vacancies are generated. In the etching treatment for forming the oxide semiconductor film 2, the oxide semiconductor film is exposed to plasma. Alternatively, when the oxide semiconductor film is exposed to hydrogen, a rare gas, ammonia, oxygen, or the like, oxygen vacancies are generated. When the material is exposed to a plasma of a mixture of oxygen and hydrogen, oxygen vacancies are generated. The conductivity of the compound semiconductor film becomes high, and the film has conductivity, and is formed as a metal oxide film 308c. It works like this.

[0160] In other words, it can be said that the metal oxide film 308c is formed using an oxide semiconductor film with high conductivity. It can also be said that the metal oxide film 308c is formed of a highly conductive metal oxide film.

[0161] In addition, when a silicon nitride film is used as the insulating film 314, the silicon nitride film contains hydrogen. Therefore, hydrogen in the insulating film 314 is formed simultaneously with the oxide semiconductor films 308a and 308b. When the hydrogen diffuses into the oxide semiconductor film, the hydrogen bonds with oxygen in the oxide semiconductor film and becomes a carrier. In addition, silicon nitride films are formed by plasma CVD or sputtering. When the oxide semiconductor film is formed by the plasma etching method, the oxide semiconductor film is exposed to plasma and oxygen vacancies are generated. When hydrogen contained in the silicon nitride film enters the oxygen vacancy, electrons, which act as carriers, are generated. As a result, the conductivity of the oxide semiconductor film becomes high and the oxide semiconductor film becomes the metal oxide film 308c. .

[0162] The metal oxide film 308c has a lower resistivity than the oxide semiconductor films 308a and 308b. The resistivity of the oxide semiconductor film 308c is 1×10 -8 1×10 times more -1 It is preferable that the ratio is less than 1×10 -3 Ωcm or more 1 ×104 Ωcm, and more preferably a resistivity of 1×10 -3 Ωcm or more 1×10 -1 It is preferable that the resistivity is less than Ωcm.

[0163] However, one aspect of the embodiment of the present invention is not limited to this. In the case In some cases, it may not be in contact with the insulating film 314 .

[0164] In addition, one aspect of the embodiment of the present invention is not limited to this, and the metal oxide film 308c may be Depending on the circumstances, the oxide semiconductor film 308a and the oxide semiconductor film 308b may be formed in different steps. In that case, the metal oxide film 308c has a different structure from the oxide semiconductor films 308a and 308b. For example, the metal oxide film 308c may be made of indium tin oxide ( Hereinafter, the insulating film 11 may be formed using ITO, indium zinc oxide, or the like.

[0165] In the liquid crystal display device described in this embodiment, 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.

[0166] The conductive films 310a, 310b, 310c, 310d, and 310e are made of aluminum, titanium, or the like. , chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or an alloy mainly composed of this metal, in a single layer structure or laminated structure. It is used as a layer structure. For example, a single layer structure of an aluminum film containing silicon, A two-layer structure in which a titanium film is laminated on a tungsten film, a two-layer structure in which a titanium film is laminated on a tungsten film, A two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a titanium film or a nitrogen film A titanium nitride film and an aluminum film or a copper film are 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 of the molybdenum film. Or a molybdenum nitride film and an aluminum layer over the molybdenum film or molybdenum nitride film. A tungsten film or copper film is laminated, and then a molybdenum film or molybdenum nitride film is formed on top of it. In addition, transparent conductive films containing indium oxide, tin oxide, or zinc oxide are also available. Materials may also be used.

[0167] The insulating film 306, the oxide semiconductor films 308a and 308b, the metal oxide film 308c, and the conductive film On the layers 310a, 310b, 310c, 310d, and 310e, an inorganic insulating film 53 is formed. An insulating film 312 and an insulating film 314 are formed. The insulating film 312 is formed in the same manner as the insulating film 306. It is preferable to use a material capable of improving interface characteristics with the oxide semiconductor film. The insulating film 312 can be formed using an oxide insulating film. 312a and 312b are laminated to form the film.

[0168] The insulating film 312a is an oxide insulating film that transmits oxygen. When the insulating film 312b is formed, the oxide semiconductor films 308a and 308b and the metal It also functions as a film for reducing damage to the oxide film 308c.

[0169] The insulating film 312a has a thickness of 5 nm to 150 nm, preferably 5 nm to 50 nm. A silicon oxide film, a silicon oxynitride film, or the like having a thickness of 1 nm or less can be used. In the present specification, a silicon oxynitride film is a film having a composition in which oxygen is more abundant than nitrogen. The term silicon nitride oxide refers to a film that contains more nitrogen than oxygen. Refers to the membrane.

[0170] The insulating film 312a is an oxide insulating film that contains nitrogen and has no vacancy. It is preferable that the amount of recession is small.

[0171] Typical examples of oxide insulating films that contain nitrogen and have few defects include silicon oxynitride films, Examples include an aluminum oxynitride film.

[0172] The oxide insulating film with few defects shows a high ESR spectrum below 100K. The first signal has a g value of 2.037 to 2.039, and the second signal has a g value of 2.001 to 2. A second signal with a g value of 0.003 or less, and a third signal with a g value of 1.964 to 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 to 2.039, and the second signal has a g value of 2.0 A second signal with a g value between 1.01 and 2.003, and a second signal with a g value between 1.964 and 1.966, The total spin density of a third signal is 1×10 18 spins / cm 3 Less than , typically 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 less than It is.

[0173] In addition, in the ESR spectrum below 100K, the g value is 2.037 to 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). Representative examples of nitrogen oxides include: Nitric oxide, nitrogen dioxide, etc. That is, the first group has a g value of 2.037 or more and 2.039 or less. A signal with a g-value between 2.001 and 2.003, and a second signal with a g-value between 1.96 and 2.003. The smaller the sum of the spin densities of the third signals, which is greater than or equal to 4 and less than or equal to 1.966, the more likely the oxide is to have a high spin density. It can be said that the content of nitrogen oxides in the insulating film is small.

[0174] If the insulating film 312a contains a small amount of nitrogen oxide as described above, the insulating film 312a and the oxide It is possible to reduce carrier traps at the interface with the oxide semiconductor film. As a result, it is possible to reduce the shift in threshold voltage of a transistor included in a display device. This makes it possible to reduce fluctuations in the electrical characteristics of the transistor.

[0175] The insulating film 312a is formed by SIMS (Secondary Ion Mass Spectroscopy). The nitrogen concentration measured by ion trometry is 6×10 20 atoms / cm 3 Is less than or equal to As a result, nitrogen oxides are less likely to be generated in the insulating film 312a. In addition, carrier transport at the interface between the insulating film 312a and the oxide semiconductor films 308a and 308b In addition, the threshold voltage of the transistor included in the display device can be reduced. It is possible to reduce the voltage shift and thus the variation in the electrical characteristics of the transistor. This can be done.

[0176] If the insulating film 312a contains nitrogen oxides and ammonia, the manufacturing process During the heat treatment process, nitrogen oxides and ammonia react to produce nitrogen oxides. As a result, the nitrogen concentration and the nitrogen oxide concentration in the insulating film 312a are In addition, the insulating film 312a and the oxide semiconductor film 308a and It is possible to reduce carrier traps at the interface with 08b. It is possible to reduce the shift in the threshold voltage of the transistor included in the device, This can reduce the fluctuation in the electrical characteristics of the transistor.

[0177] In the insulating film 312a, all of the oxygen that has entered the insulating film 312a from the outside is Some oxygen does not move to the outside of the insulating film 312a and remains in the insulating film 312a. At the same time, oxygen contained in the insulating film 312a moves out of the insulating film 312a. This may cause oxygen to move in the insulating film 312a.

[0178] When an oxide insulating film that transmits oxygen is formed as the insulating film 312a, The oxygen desorbed from the insulating film 312b is guided to the oxide semiconductor film 312 via the insulating film 312a. It can be moved to 308a, 308b.

[0179] An insulating film 312b is formed in contact with the insulating film 312a. The insulating film is formed using an oxide insulating film containing more oxygen than the oxygen that satisfies the stoichiometric composition. When an oxide insulating film contains more oxygen than the stoichiometric composition, some of the oxygen is removed by heating. The oxide insulating film containing more oxygen than the stoichiometric composition has a TD In the S analysis, the amount of oxygen desorbed was 1.0 x 10 18 atoms / cm3 More than 3.0×10 20 atoms / cm 3 The oxide insulating film is as described above. The surface temperature of the film during the TDS analysis was 100°C or higher and 700°C or lower. The temperature is preferably in the range of 100° C. or higher and 500° C. or lower.

[0180] The insulating film 312b has a thickness of 30 nm to 500 nm, preferably 50 nm or more. Silicon oxide, silicon oxynitride, etc., having a thickness of 400 nm or less can be used.

[0181] In addition, it is preferable that the insulating film 312b has a small amount of defects. 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 312b is made of an oxide semiconductor material, which is smaller than the insulating film 312a. Since it is separated from the conductor films 308a and 308b, the defect density is higher than that of the insulating film 312a. Good too.

[0182] The insulating film 314 is made of a blocking material such as oxygen, hydrogen, water, an alkali metal, an alkaline earth metal, etc. By providing the nitride insulating film having a blocking effect, the oxide semiconductor films 308a, 308b, and It is possible to prevent oxygen from diffusing from the metal oxide film 308c to the outside. Examples of the material include silicon nitride, silicon oxynitride, aluminum nitride, and aluminum oxynitride. be.

[0183] 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 is preferably used. Aluminum, Aluminum Oxide Nitride, Gallium Oxide, Gallium Oxide Nitride, Yttrium Oxide , yttrium oxide nitride, hafnium oxide, hafnium oxide nitride, etc. In order 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 sealing effect. stomach.

[0184] In addition, a conductive film 316b is formed on the insulating film 314. 314 and can function as an electrode of a capacitor element.

[0185] The conductive film 316b can be formed using a light-transmitting conductive material. Examples of conductive materials having optical properties include indium oxide containing tungsten oxide, tungsten oxide, Indium zinc oxide with tin oxide, Indium oxide with titanium oxide, Titanium oxide Indium tin oxide, ITO, indium zinc oxide, indium oxide doped with silicon oxide Examples include zinc tin oxide.

[0186] The organic insulating film 317 is made of organic resin such as acrylic resin, polyimide, or epoxy resin. The organic insulating film 317 may preferably have a thickness of 500 nm or more and 5000 nm or less. The thickness of the organic insulating film 317 is set to the above thickness. By doing so, it is possible to fill the recesses on the conductive film 316b with the organic insulating film 317. This can reduce unevenness in the region where the alignment film 320 is formed.

[0187] By forming the organic insulating film 317 using an organic resin, at least the recess of the conductive film 316b The liquid crystal layer 321 can be filled with an organic insulating film 317. It is possible to reduce unevenness in the direction.

[0188] In addition, conductive films 319 and 319a are formed on the organic insulating film 317. 9 functions as a pixel electrode. The conductive film 319a has an opening 364a (see FIG. 9A). ) and is electrically connected to the conductive film 304b in the opening 364b (see FIG. 9A). That is, the conductive film 304b and the conductive film 310c are electrically connected to each other. It functions as a connection electrode for connecting

[0189] The organic insulating film 317 is not limited to this. For example, the organic insulating film 317 may be a color filter. For example, the organic insulating film 31 may have a function of a black matrix. When the pixel 7 has a function of a color filter, for example, a red pixel, a blue pixel, a green pixel, In this case, the organic insulating film 317 having color properties may be formed for each of the pixels of the respective colors.

[0190] The conductive films 319 and 319a are formed using a light-transmitting conductive material similar to the conductive film 316b. It can be formed.

[0191] In order to form a connection structure in which the conductive film 304b and the conductive film 310c are in direct contact with each other, Before forming the film 310c, a pattern is formed in order to form openings in the insulating films 305 and 306. However, as shown in Figure 4, a mask for turning is required. The conductive film 304b is connected to the conductive film 310c by the conductive film 319a. In addition, it is no longer necessary to form a connection portion where the conductive film 310c is in direct contact, and a single photomask is required. That is, the number of steps for manufacturing a liquid crystal display device can be reduced.

[0192] The alignment film 320 is preferably light-transmitting, and is typically made of acrylic resin, polycarbonate, or the like. For example, organic resins such as polyimide and epoxy resins can be used.

[0193] In addition, a film having color (hereinafter, referred to as a color film 346) is formed on the substrate 342. The colored film 346 functions as a color filter. An adjacent light-shielding film 344 is formed on the substrate 342. The light-shielding film 344 is a black matrix. The colored film 346 does not necessarily have to be provided. For example, a liquid crystal display may be used. In some cases, such as when the display device is black and white, the color film 346 may not be provided.

[0194] The colored film 346 may be a colored film that transmits light of a specific wavelength band. For example, A red (R) color filter transmits light in the color wavelength band, and a green (G) color filter transmits light in the color wavelength band. A green (G) color filter transmits light in the blue wavelength range, and a blue (B) color filter transmits light in the blue wavelength range. Alternatively, the colored film 346 may be a filter that transmits the light from the light source as it is. For example, the light-transmitting layer may be made of acrylic. Organic resins such as resin, polyimide, and epoxy resin can be used.

[0195] The light-shielding film 344 may be a metal film having a function of blocking light of a specific wavelength band. Alternatively, an organic insulating film containing a black pigment or the like can be used.

[0196] In addition, an insulating film 348 is formed on the colored film 346. The insulating film 348 is a planarizing layer. or to suppress the diffusion of impurities that may be contained in the colored film 346 to the liquid crystal element side. It has the function of

[0197] In addition, a conductive film 350 is formed on the insulating film 348. The conductive film 350 is The conductive film 319 and the conductive film 319 function as the other of the pair of electrodes of the liquid crystal element. An alignment film 320 is formed on the a, and an alignment film 352 is formed on the conductive film 350.

[0198] In addition, a liquid crystal layer 321 is formed between the conductive films 319, 319a and the conductive film 350. The liquid crystal layer 321 is formed by sealing the substrate 302 and the substrate 342 with a sealing material (not shown). The sealant is used to prevent moisture from entering from the outside. In particular, a configuration in which the inorganic material is in contact with the inorganic material is preferred.

[0199] In addition, the thickness of the liquid crystal layer 321 (cell gap) is set between the conductive films 319, 319a and the conductive film 350. A spacer may be provided to maintain the gap (also called a gap).

[0200] A method for manufacturing an element portion provided on a substrate 302 in the liquid crystal display device shown in FIG. 5 to 8. In this embodiment, the element portion provided on the substrate 302 is refers to the region sandwiched between the substrate 302 and the alignment film 320.

[0201] 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 most common deposition 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.

[0202] In the thermal CVD method, the source gas and the oxidizing agent are fed into the chamber at the same time, and the pressure inside the chamber is raised to atmospheric pressure. The film is formed by reacting the reactants near or on the substrate under reduced pressure and depositing them on the substrate. In this way, since 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 plasma damage.

[0203] In addition, in the ALD method, the pressure inside the chamber is set to atmospheric pressure or reduced pressure, and the source gas for the reaction is sequentially The gas may then be introduced into the chamber, and the gas introduction sequence may be repeated to form a film. For example, by switching each switching valve (also called high-speed valve), two or more types of The source gases are sequentially supplied to the chamber, and the first source gas is supplied to the chamber so as not to mix the source gases. Inert gas (argon, nitrogen, etc.) is introduced simultaneously with or after the feed gas. In addition, when an inert gas is introduced at the same time, the inert gas is The second source gas may be introduced simultaneously with the introduction of the inert gas. Also, instead of introducing an inert gas, the first source gas is discharged by evacuation. The first source gas is adsorbed on the surface of the substrate to form a first layer. The second layer is deposited on the first layer by reacting with the second source gas introduced later. A thin film is formed.

[0204] This gas introduction sequence is controlled and repeated several times until the desired thickness is achieved. 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 fine transistors. This is suitable for manufacturing.

[0205] First, prepare a substrate 302. Here, a glass substrate is used as the substrate 302.

[0206] Next, a conductive film is formed on the substrate 302 and processed into a desired shape. The conductive films 304a, 304b, and 304c are formed. The formation of the first patterning is performed by forming a mask in a desired region, and the first patterning is performed by forming a mask in a desired region. The non-insulated areas can be etched away to form the voids.

[0207] The conductive films 304a, 304b, and 304c are typically formed by a sputtering method. It can be formed using vacuum deposition, pulsed laser deposition (PLD), thermal CVD, etc. Cut.

[0208] In addition, conductive films 304a, 304b, and 304c are formed by a film forming apparatus using ALD. In this case, WF 6 Gas and B 2 H 6 Gas is sequentially The initial tungsten film is then formed by repeatedly introducing WF 6 Gas and H 2 Gas is introduced simultaneously The tungsten film is formed by implanting the 2 H 6 Instead of gas, SiH 4 Even with gas good.

[0209] Next, an insulating film 305 is formed on the substrate 302 and the conductive films 304a, 304b, and 304c. Then, an insulating film 306 is formed over the insulating film 305 (see FIG. 5(A)).

[0210] The insulating film 305 and the insulating film 306 are formed by sputtering, CVD, vacuum deposition, pulse laser deposition, or the like. The insulating film 30 can be formed by a laser deposition (PLD) method, a thermal CVD method, or the like. It is preferable to form the insulating film 306 and the insulating layer 5 in succession in a vacuum, since this prevents the inclusion of impurities.

[0211] A silicon oxide film or a silicon oxynitride film is formed as the insulating film 305 and the insulating film 306. In this case, it is preferable to use a deposition gas containing silicon and an oxidizing gas as the source gas. Representative examples of silicon-containing deposition gases include silane, disilane, trisilane, Examples of oxidizing gases include oxygen, ozone, nitrous oxide, and nitrogen dioxide. etc.

[0212] In addition, when forming a gallium oxide film as the insulating film 305 and the insulating film 306, MOCVD is used. (Metal Organic Chemical Vapor Deposition ) method.

[0213] The insulating film 305 and the insulating film 306 are formed by a thermal CVD method such as an MOCVD method or an ALD method. When a hafnium oxide film is formed using a solvent containing a hafnium precursor compound, Liquid (hafnium alkoxide solution, typically tetrakisdimethylamidohafnium ( The raw gas is vaporized from ozone (O2) as an oxidizing agent. 3 ) two types of gas The chemical formula for tetrakisdimethylamidohafnium is Hf[N(CH3 ) 2 ] 4 Other material liquids include tetrakis(ethylmethylamido)hafnium. There are some.

[0214] The insulating film 305 and the insulating film 306 are formed by a thermal CVD method such as an MOCVD method or an ALD method. In the case of forming an aluminum oxide film using the above-mentioned method, a solvent and an aluminum precursor compound are mixed. The raw material gas is made by vaporizing a liquid containing trimethylaluminum (TMA), an oxidizer, and H 2 Two types of gases are used: Al(C H 3 ) 3 Other material liquids include tris(dimethylamido)aluminum, Triisobutylaluminum, Aluminum tris(2,2,6,6-tetramethyl-3 ,5-heptanedionate).

[0215] The insulating film 305 and the insulating film 306 are formed by a thermal CVD method such as an MOCVD method or an ALD method. When forming a silicon oxide film using the above method, hexachlorodisilane is adsorbed on the film formation surface. This removes the chlorine contained in the adsorbed material and releases the oxidizing gas (O 2 , nitrous oxide) radicals The adsorbate is reacted with the adsorbate.

[0216] Next, an oxide semiconductor film 307 is formed over the insulating film 306 (see FIG. 5B).

[0217] The oxide semiconductor film 307 can be formed by a sputtering method, a coating method, a pulsed laser deposition method, a laser deposition method, or the like. It can be formed by using an ablation method, a thermal CVD method, or the like.

[0218] The sputtering gas is a rare gas (typically argon), oxygen, or a mixture of a 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

[0219] Further, the target may be appropriately selected depending on the composition of the oxide semiconductor film to be formed.

[0220] 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.

[0221] In addition, the following conditions are preferably applied to form the CAAC-OS film.

[0222] 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 may be reduced. A deposition gas having a temperature of 80° C. or less, preferably −100° C. or less, is used.

[0223] Using a deposition system that utilizes ALD, an oxide semiconductor film, such as an In-Ga-Zn-O film, is formed. In this case, In(CH 3 ) 3 Gas and O 3 The gas is introduced repeatedly to form an In-O layer. Then, Ga(CH 3 ) 3 Gas and O 3 Gases are introduced simultaneously to form a GaO layer, and then Then Zn(CH3 ) 2 and O 3 Gas is introduced at the same time to form a ZnO layer. The order of these layers is not limited to this example. In addition, it is possible to mix these gases to form In-Ga-O layers or In A mixed compound layer such as a Ga-Zn-O layer or a Ga-Zn-O layer may be formed. 3 gas Instead of H, we bubbled with an inert gas such as Ar. 2 O gas may be used, but it must not contain H. I O 3 It is preferable to use In(CH 3 ) 3 Instead of gas, In(C 2 H 5 ) 3 Gas may also be used. 3 ) 3 Instead of gas, Ga(C 2 H 5 ) 3 Gas may also be used. Zn(CH 3 ) 2 A gas may also be used.

[0224] Next, the oxide semiconductor film 307 is processed into a desired shape to form an island-shaped oxide semiconductor film 30 The oxide semiconductor films 308a, 308b, and 308d are formed. The formation of 8d is performed by forming a mask by a second patterning in a desired area, and then forming a The uncovered areas can be etched away by , dry etching, wet etching, or a combination of both. (See FIG. 5(C)).

[0225] After that, heat treatment is performed to remove the oxide semiconductor films 308a, 308b, and 308d. Hydrogen, water, and the like contained in the oxide semiconductor films 308a, 308b, and 308d are released. As a result, the oxygen concentration and the water concentration of the highly purified oxide semiconductor film 308a , 308b, 308d can be formed. The temperature of the heat treatment is typically 25 The temperature is 0° C. or higher and 650° C. or lower, preferably 300° C. or higher and 500° C. or lower. The temperature is typically 300° C. or higher and 400° C. or lower, preferably 320° C. or higher and 370° C. or lower. By doing so, it is possible to reduce warping and shrinkage of the board even in large boards. This improves the yield.

[0226] 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 distortion 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.

[0227] The heat treatment is carried out in an atmosphere of nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably Air at less than 1 ppm, preferably less than 10 ppb), 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. In addition, 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.

[0228] In addition, when the film formation temperature of the insulating film 311a to be formed later is set to 280° C. or more and 400° C. or less, Hydrogen, water, and the like contained in the oxide semiconductor films 308a, 308b, and 308d are eliminated. Since this is possible, the heat treatment is not necessary.

[0229] Next, a conductive film 303 is formed over the insulating film 306 and the oxide semiconductor films 308a, 308b, and 308d. 9 is formed (see FIG. 6(A)).

[0230] The conductive film 309 can be formed by sputtering, vacuum deposition, pulsed laser deposition (PLD), etc. The film can be formed by a method such as a thermal CVD method.

[0231] Next, the conductive film 309 is processed into a desired shape to form conductive films 310a, 310b, and 310 In addition, the conductive films 310a, 310b, 310c, 310d, and 310e are formed. The formation of 310d and 310e involves forming a mask by third patterning in a desired area; The regions not covered by the mask can be etched to form the etched region (FIG. 6( See B). ).

[0232] Next, the insulating film 306, the oxide semiconductor films 308a, 308b, and 308d, and the conductive film 310 Insulating films 311a, 311b, 310c, 310d, and 310e are formed on the insulating films 311a, 311c, 311d, and 311e. b is laminated to form an insulating film 311 (see FIG. 6(C)). The insulating film 311 is The film can be formed by using a deposition method, a CVD method, a vapor deposition method, or the like.

[0233] After the insulating film 311a is formed, the insulating film 311b is successively formed without exposing the insulating film 311a to the air. After the insulating film 311a is formed, the flow rate of the source gas is controlled without exposing the insulating film 311a to the atmosphere. The insulating film 311b is continuously formed by adjusting one or more of the pressure, the high frequency power, and the substrate temperature. This reduces the concentration of impurities originating from atmospheric components at the interface between the insulating films 311a and 311b. In addition, oxygen contained in the insulating film 311b can be removed by the oxide semiconductor films 308a and 308b. The oxide semiconductor films 308a, 308b, and 308d can be moved to the oxide semiconductor films 308a, 308b, and 308d. The amount of oxygen vacancy in 8d can be reduced.

[0234] The insulating film 311a is formed by mixing an oxidizing gas with a deposition gas in an amount of more than 20 times and less than 100 times. and the pressure in the treatment chamber is less than 100 Pa, preferably 40 times or more and 80 times or less. By using a CVD method with a pressure of 50 Pa or less, an oxide containing nitrogen and with few defects can be obtained. An insulating film can be formed.

[0235] As the source gas for the insulating film 311a, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of deposition gases containing silicon include silane, disilane, trisilane, and tetrasilane. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, and Nitric oxide, etc.

[0236] By using the above conditions, an oxide insulating film that transmits oxygen is formed as the insulating film 311a. In addition, by providing the insulating film 311a, the shape of the insulating film 311b to be formed later can be controlled. In the deposition process, damage to the oxide semiconductor films 308a, 308b, and 308d can be reduced. It is.

[0237] The insulating film 311b is formed on a substrate placed in a processing chamber of a plasma CVD apparatus that has been evacuated to a vacuum. The plate is kept at a temperature of 180° C. or higher and 280° C. or lower, more preferably 200° C. or higher and 240° C. or lower, A raw material gas is introduced into the processing chamber to set the pressure in the processing chamber to 100 Pa or more and 250 Pa or less, More preferably, the pressure is set to 100 Pa or more and 200 Pa or less, and the pressure applied to the electrode provided in the processing chamber is set to 0.1 7W / cm 2 More than 0.5W / cm 2 Less than or equal to 0.25 W / cm 2 Above 0. 35W / cm 2 Silicon oxide film or oxynitride film is formed by supplying the following high frequency power. A silicon film is formed.

[0238] As the source gas for the insulating film 311b, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of deposition gases containing silicon include silane, disilane, trisilane, and tetrasilane. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, and Nitric oxide, etc.

[0239] The insulating film 311b is formed under the following conditions: By supplying power, the efficiency of decomposing the source gas in the plasma increases, and the number of oxygen radicals increases. Since the oxidation of the source gas proceeds, the oxygen content in the insulating film 311b becomes higher than the stoichiometric ratio. However, if the substrate temperature is the deposition temperature of the insulating film 311b, the silicon Because the bond between fluorine and oxygen is weak, some of the oxygen is released by heating. Oxide insulation that contains more oxygen than meets the composition and loses some of the oxygen when heated In addition, an insulating film can be formed over the oxide semiconductor films 308a, 308b, and 308d. Therefore, in the step of forming the insulating film 311b, The oxide semiconductor film 311a serves as a protective film for the oxide semiconductor films 308a, 308b, and 308d. High power density while reducing damage to the compound semiconductor films 308a, 308b, and 308d. The insulating film 311b can be formed using this high frequency power.

[0240] In addition, in the film formation conditions of the insulating film 311b, a deposition gas containing silicon is mixed with an oxidizing gas. By increasing the flow rate of the gas, it is possible to reduce the number of defects in the insulating film 311b. Specifically, ESR measurements reveal that the g value is 2.001, which is due to the dangling bonds of silicon. The spin density of the signal that appears is 6×10 17 spins / cm 3 Less than 3 x 10 1 7 spins / cm 3 Less than or equal to 1.5×10 17 spins / cm 3 Is less than or equal to It is possible to form an oxide insulating film with a small number of defects. As a result, the reliability of the transistor is improved. It can be improved.

[0241] 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, the temperature is 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 board can be prevented even in large boards. It is possible to reduce the number of defects, thereby improving the yield.

[0242] The heat treatment can be performed using an electric furnace, an RTA device, or the like. In this case, the heat treatment can be performed at a temperature equal to or higher than the distortion point of the substrate for a short period of time. This can shorten the processing time.

[0243] Heat treatment is carried out in a vacuum of 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 above-mentioned nitrogen, oxygen, ultra-dry air, or rare gas, hydrogen, water, etc. may be added to the atmosphere. It is preferred that it does not include.

[0244] By this heat treatment, part of oxygen contained in the insulating film 311b is oxidized to the oxide semiconductor film 308a, The oxide semiconductor films 308a, 308b, and 308d are As a result, oxygen vacancies in the oxide semiconductor films 308a and 308b can be reduced. , the amount of oxygen vacancies contained in 308d can be further reduced.

[0245] In addition, when the insulating films 311a and 311b contain water, hydrogen, etc., the insulating films 311a and 311b are provided with a blocking function to block the water, hydrogen, etc. When an insulating film 313 having a function of forming the insulating film 311a and the insulating film 311b is formed later and subjected to a heat treatment, Water, hydrogen, and the like contained in 1b move to the oxide semiconductor films 308a, 308b, and 308d. Defects are generated in the oxide semiconductor films 308a, 308b, and 308d. This heating makes it possible to remove water, hydrogen, etc. contained in the insulating films 311a and 311b. This reduces the variation in the electrical characteristics of the transistors and also suppresses the variation in the threshold voltage. It can be controlled.

[0246] In addition, by forming the insulating film 311b on the insulating film 311a while heating, the oxide semiconductor Oxygen is transferred to the oxide semiconductor films 308a, 308b, and 308d. Since it is possible to reduce the oxygen vacancies contained in 308d, the heat treatment is not required. It would be good.

[0247] In addition, when the conductive films 310a, 310b, 310d, and 310e are formed, the conductive films are etched. The oxide semiconductor films 308a, 308b, and 308d are damaged by the oxidation. The back channel of the conductor films 308a and 308b (the oxide semiconductor films 308a and 308b) The surface opposite to the surface facing the conductive films 304a and 304c functioning as gate electrodes However, oxygen vacancies occur in the insulating film 311b. By applying the oxide insulating film containing oxygen, The generated oxygen vacancies can be repaired. Since the defects contained in b can be reduced, the reliability of the transistor can be improved. can be done.

[0248] Note that this heat treatment may be performed after the opening 362, which will be formed later, is formed.

[0249] Next, the insulating film 311 is processed into a desired shape to form an insulating film 312 and an opening 362. The insulating film 312 and the opening 362 are formed in a desired region by applying a fourth pattern. forming a mask by etching and then etching the areas not covered by the mask; (See FIG. 7(A)).

[0250] Note that the opening 362 is formed so that the surface of the oxide semiconductor film 308d is exposed. The portion 362 can be formed by, for example, dry etching. It is preferable to etch the insulating film 311 by a dipping etching method. Since the oxide semiconductor film 308d is exposed to plasma during the etching process, However, it is possible to increase the oxygen vacancies in the opening 362. Examples of the etching method include, but are not limited to, a wet etching method, or a combination of a dry etching method and a wet etching method. A forming method combining a thermal etching method may be used.

[0251] Next, the insulating film 313 is formed over the insulating film 312 and the oxide semiconductor film 308d (FIG. 7B )reference.).

[0252] The insulating film 313 is made of a material that is free of impurities from the outside, such as oxygen, hydrogen, water, alkali metals, and alkali. It is preferable to use a material that prevents an alkali earth metal or the like from diffusing into the oxide semiconductor film. Furthermore, it is preferable that the insulating material contains hydrogen, and typically contains nitrogen, for example, a nitride insulating material. The insulating film 313 can be formed by, for example, a CVD method or a sputtering method. The method can be used to form the sintered body.

[0253] When the insulating film 313 is formed by a plasma CVD method or a sputtering method, an oxide semiconductor film The insulating film 313 is exposed to plasma, and oxygen vacancies are generated in the oxide semiconductor film. External impurities, such as water, alkali metals, and alkaline earth metals, may be present in the oxide semiconductor film. The insulating film 3 is made of a material that prevents diffusion of hydrogen into the semiconductor substrate. When hydrogen of 13 is diffused into the oxide semiconductor film 308d, Hydrogen is bonded to oxygen to generate electrons as carriers. When hydrogen enters the oxygen vacancy, electrons are generated as carriers. The metal oxide semiconductor film 308d becomes highly conductive and turns into the metal oxide film 308c.

[0254] In addition, the nitride insulating 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. In addition, when the oxide semiconductor film is formed at a high temperature, the oxide semiconductor film is preferably formed at a high temperature. Oxygen is released from the oxide semiconductors used as 308a and 308b, and the carrier concentration increases. Since a phenomenon in which this occurs can occur, the temperature must be set at a level at which this phenomenon does not occur.

[0255] Next, a conductive film 315 is formed over the insulating film 313 (see FIG. 8A).

[0256] The conductive film 315 can be formed by, for example, a sputtering method.

[0257] Next, the conductive film 315 is processed into a desired shape to form the conductive film 316b. The conductive film 316b is formed by forming a mask by a fifth patterning in a desired region. The area not covered by the mask can be etched away (FIG. 8(B) )reference.).

[0258] Next, an organic insulating film 317 is formed so as to cover the insulating film 313 and the conductive film 316b (FIG. 8( The organic insulating film 317, which functions as a planarizing film, is formed on the insulating film 313 when a part of the insulating film 313 is exposed. The housing has an opening so that the housing can be opened.

[0259] The organic insulating film 317 is formed by applying a coating method such as spin coating or dip coating. After applying a photoresist composition onto the insulating film 313 and the conductive film 316b, a sixth photomask is used. The composition is exposed to light and developed by the photolithography process described above, and then a heat treatment is performed. In addition, when a non-photosensitive composition is applied onto the insulating film 313 and the conductive film 316b, A resist is applied onto the composition, and a photolithography process is performed using a sixth photomask. The resist is processed to form a mask, and the non-photosensitive composition is etched using the mask. In this way, the organic insulating film 317 can be formed.

[0260] The organic insulating film 317 is formed by a wet method such as an inkjet method or a printing method. This makes it possible to reduce the number of photomasks.

[0261] Next, the insulating film 305, the insulating film 306, the insulating film 312, and the insulating film 313 are etched to form an opening 3 exposing the conductive film 304b. 64a, an opening 364b exposing the conductive film 310c, and an opening 364b exposing the conductive film 310e. A portion 364c is formed (see FIG. 9(A)).

[0262] Next, a conductive film 318 is formed (see FIG. 9B).

[0263] The conductive film 318 can be formed by, for example, a sputtering method.

[0264] Next, the conductive film 318 is processed into a desired shape to form conductive films 319 and 319a. The conductive films 319 and 319a are formed in desired regions by a mask patterning process using the seventh patterning method. The mask may be formed by forming a mask and then etching the area not covered by the mask. (See Figure 9(C).)

[0265] Through the above steps, a pixel portion having a transistor and a driver circuit portion are formed over the substrate 302. In the manufacturing process shown in this embodiment, the first to seventh patternings can be performed. This means that transistors and capacitors can be formed simultaneously using seven photomasks. can.

[0266] In this embodiment, hydrogen contained in the insulating film 313 is diffused into the oxide semiconductor film 308d. The conductivity of the oxide semiconductor film 308d was increased by applying heat to the oxide semiconductor films 308a and 308 b is covered with a mask, and impurities, typically, hydrogen, boron, or phosphorus, are added to the oxide semiconductor film 308d. , tin, antimony, rare gas elements, alkali metals, alkaline earth metals, etc. are added to oxidize The oxide semiconductor film 308d may be doped with hydrogen, boron, or Methods for adding phosphorus, tin, antimony, rare gas elements, etc. include ion doping, On the other hand, the oxide semiconductor film 308d is formed by a ion implantation method. The metal or the like is added by applying a solution containing the impurity to the oxide semiconductor film 308d. There is a way.

[0267] Next, the element portion provided on the substrate 342 provided opposite the substrate 302 will be described below. In this embodiment, the element portion provided on the substrate 342 is a substrate 342 and This refers to the region sandwiched between the alignment films 352.

[0268] First, a substrate 342 is prepared. The substrate 342 may be made of the same material as that used for the substrate 302. Next, a light-shielding film 344 and a colored film 346 are formed on the substrate 342 (FIG. 10(A) )reference.).

[0269] The light-shielding film 344 and the colored film 346 can be formed by using various materials, by printing, ink-jet printing, or printing with a film. They are formed at desired positions by an etching method using photolithography technology.

[0270] Next, an insulating film 348 is formed on the light-shielding film 344 and the colored film 346 (see FIG. 10(B)). .).

[0271] The insulating film 348 is made of an organic insulating material such as acrylic resin, epoxy resin, polyimide, etc. By forming the insulating film 348, for example, the colored film 346 It is possible to prevent impurities contained therein from diffusing to the liquid crystal layer 321 side. However, the insulating film 348 is not necessarily required, and a structure in which the insulating film 348 is not formed may be used. good.

[0272] Next, a conductive film 350 is formed over the insulating film 348 (see FIG. 10C). As the conductive film 315, the materials shown in the conductive film 315 can be used.

[0273] Through the above steps, the structure formed on the substrate 342 can be formed.

[0274] Next, the insulating film 317 formed on the substrate 302 and the substrate 342, more specifically, on the substrate 302, , on the conductive films 319 and 319a, and on the conductive film 350 formed on the substrate 342, The alignment film 320 and the alignment film 352 are formed by a rubbing method. The substrate 302 and the substrate 342 are then bonded to each other by a photoalignment method or the like. The liquid crystal layer 321 is formed on the substrate 321. The liquid crystal layer 321 is formed by a dispenser method (a dripping method). ) or by bonding the substrate 302 and the substrate 342 together and then injecting liquid crystal using capillary action. Injection techniques can be used.

[0275] Through the above steps, the liquid crystal display device shown in FIG. 4 can be manufactured.

[0276] 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.

[0277] (Embodiment 3) In this embodiment, a liquid crystal display device including a transistor different from that in Embodiment 1 will be described. This will be explained with reference to FIG. 11 to FIG.

[0278] The liquid crystal display device shown in FIG. 11 has a dual gate structure in the driving circuit section indicated by AB. The semiconductor device is characterized by having a transistor 102a.

[0279] The transistor 102a provided in the driving circuit section has a gate electrode provided on a substrate 302. and the insulating films 305 and 306 functioning as the gate insulating film 51. 6, an oxide semiconductor film 308a formed on the insulating film 306, and and conductive films 310a and 310b which function as a source electrode and a drain electrode, In addition, an inorganic insulating film 53 is formed over the oxide semiconductor film 308a and the conductive films 310a and 310b. A conductive film 316d that functions as a gate electrode is formed on the inorganic insulating film 53. The conductive film 316d functioning as a gate electrode is formed on the gate insulating film 51 and the inorganic insulating film 53. In the opening (not shown), a conductive film 304a which functions as a gate electrode is formed. That is, the conductive film 304a and the conductive film 316d have the same potential.

[0280] Therefore, by applying the same voltage to each gate electrode of the transistor 102a, Reduction of characteristic variations, suppression of degradation during GBT stress testing, and performance at different drain voltages In addition, the oxide semiconductor film 308a can suppress a change in a rise voltage of an on-state current. In the case of As a result, the on-state current of the transistor 102a increases and the field effect The mobility is high, typically with a field effect mobility of 20 cm 2 / V s or more.

[0281] At the edge of the oxide semiconductor film that is processed by etching or the like, damage caused by the processing may occur. This leads to the formation of defects and contamination by impurities, which causes stresses such as electric fields. It is easily activated by being given, and it tends to become n-type (low resistance). Therefore, the end portion of the oxide semiconductor film 308a overlapping with the conductive film 304a functioning as a gate electrode The n-type end portion is connected to the source electrode and the drain electrode. When the n-type region is provided between the conductive films 310a and 310b, which function as a carrier, However, the rear pass is formed, forming a parasitic channel. In the above, the conductive film 316d that functions as a gate electrode is provided. The side surfaces of the oxide semiconductor film 308a and the conductive film 316d functioning as a conductive film are influenced by an electric field of the conductive film 316d. The occurrence of parasitic channels at the ends including the side surfaces and their vicinity is suppressed. A transistor with excellent electrical characteristics in which the drain current increases sharply with the threshold voltage. It becomes.

[0282] Note that the conductive film 316d functioning as a gate electrode is the same as the conductive film 316b shown in Embodiment 2. Materials similar to those mentioned above can be used appropriately.

[0283] <Variation 1> The liquid crystal display device shown in FIG. 11 of the third embodiment uses dual-channel transistors as the transistors in the driving circuit section. The transistor is made of a double-gate structure, but as shown in Figure 12, The driver circuit shown in FIG. 1 has a transistor 102a with a dual gate structure, and 10 may be used in the pixel portion having a dual-gate structure.

[0284] The transistor 103a is a gate electrode formed on a conductive film 3 04c, insulating films 305 and 306 functioning as a gate insulating film 51, and a The oxide semiconductor film 308b to be formed and the source electrode and the The gate insulating film 310 has conductive films 310d and 310e which function as drain electrodes and the gate insulating film 310b which function as drain electrodes. An inorganic insulating film 53 is formed on the conductive film 308b and the conductive films 310d and 310e. A conductive film 316e functioning as a gate electrode is formed on the gate electrode 53. The conductive film 316e is formed through an opening (illustrated) provided in the gate insulating film 51 and the inorganic insulating film 53. In the second embodiment, the conductive film 304c functions as a gate electrode. The film 304c and the conductive film 316e are at the same potential.

[0285] The pixel section, together with the driver circuit section, is made of highly reliable, large on-current, and high field effect mobility By providing a transistor with a dual gate structure, a liquid crystal display device with excellent display quality can be created. It can be manufactured.

[0286] <Variation 2> In the liquid crystal display device shown in the second or third embodiment, as shown in FIG. The organic insulating film 31 is a region that overlaps with the transistor 102a provided in the driving circuit section. A conductive film 319b formed at the same time as the conductive film 319 may be provided on the conductive film 319. b can be any potential such as a common potential or a ground potential. By providing the conductive film 319b overlapping with the transistor 102a, An electric field generated by a voltage applied to the conductive film 316d functioning as a gate electrode is As a result, alignment failure of the liquid crystal layer 321 caused by the electric field can be prevented. This can be prevented.

[0287] <Variation 3> In the second or third embodiment, the organic insulating film 317 is provided in the driving circuit section and the pixel section. However, as shown in FIG. 14, the liquid crystal display device having the organic insulating film 317 only in the pixel portion is described. a may be provided.

[0288] In the liquid crystal display device shown in FIG. 14, an insulating film 313 is formed as shown in FIG. After that, a mask is formed by patterning, and insulating films 305 and 30 6, 312, and 313 are etched to form openings. Next, as shown in FIG. After forming the conductive film 315 shown in FIG. 8(B), a conductive film 316b shown in FIG. A conductive film 316a is formed to connect the conductive film 304b and the conductive film 310c. An organic insulating film 317a and a conductive film 319 are formed.

[0289] As shown in FIG. 15, when the organic insulating film 317a is not provided in the driving circuit section, A conductive film 316d serving as a gate electrode of the transistor 102a having a gate structure is provided on the conductive film 316d. A conductive film 319c formed simultaneously with the conductive film 319 may be provided. <Variation 4>

[0290] In the second and third embodiments, a liquid crystal element is used as an example of a display element. As described above, various display elements can be used. As an example, an organic EL element is used. Examples of the case are shown in Figs. 23, 24, 25, and 26. The placement is for organic resin films such as acrylic resin, polyimide, and epoxy resin 371, and for organic resin films The pixel has an EL layer 373 and a common electrode 375 provided on the EL layer. The conductive film 319, the EL layer 373, and the common electrode 375 constitute an organic EL element.

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

[0292] (Embodiment 4) The transistors 102, 102a, 103, and 103a described in Embodiments 2 and 3 In the above, the oxide semiconductor film may have a stacked structure as necessary. The transistor 103 will be used for explanation.

[0293] In the transistor shown in FIG. 16, an oxide film is formed between the insulating film 306 and the conductive films 310d and 310e. A multi-layer film 336 including a compound semiconductor film is formed.

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

[0295] The oxide semiconductor film 336b is composed of one or more of the elements constituting the oxide semiconductor film 336a. The oxide semiconductor film 336b is formed by adding one or more of the elements contained in the oxide semiconductor film 336a. Since the oxide semiconductor film 336a and the oxide semiconductor film 336b are made of Therefore, the movement of carriers is not hindered at the interface. This increases the field effect mobility of the transistor.

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

[0297] The oxide semiconductor film 336b contains In, so that the carrier mobility (electron mobility) is high. This is preferable.

[0298] The oxide semiconductor film 336b may include Al, Ti, Ga, Y, Zr, La, Ce, Nd, and Sn. Alternatively, by having Hf in a higher atomic ratio than In, the following effects may be obtained. 1) The energy gap of the oxide semiconductor film 336b is increased. (3) To reduce the electron affinity of 336b. (4) To block impurities from outside. The insulating property is higher than that of the semiconductor film 336a. (5) Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, and Hf are metal elements with strong bonding strength with oxygen, so Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf is present in a higher atomic ratio than In. This makes it difficult for oxygen deficiency to occur.

[0299] When the oxide semiconductor film 336b is an In-M-Zn oxide, the atomic ratio of In to M is When the sum of In and M is 100 atomic %, In is less than 50 atomic %, and M is 50 atomic % or more, more preferably, In is less than 25 atomic % and M is 7 Must be 5 atomic% or more.

[0300] In addition, the oxide semiconductor film 336a and the oxide semiconductor film 336b are made of In-M-Zn oxide ( M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf) oxide Compared with the semiconductor film 336a, the oxide semiconductor film 336b contains M (Al, Ti, Ga , Y, Zr, La, Ce, Nd, Sn or Hf) have a large atomic ratio, and typically, The amount of the atoms contained in the compound semiconductor film 336a is 1.5 times or more, and preferably 2 times or more. More preferably, the atomic ratio is at least three times higher.

[0301] In addition, the oxide semiconductor film 336a and the oxide semiconductor film 336b are made of In-M-Zn oxide ( M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf) oxide The semiconductor film 336b is In:M:Zn=x 1 :y 1 :z 1 [Atomic ratio], oxide semiconductor film 3 36a In:M:Zn=x 2 :y 2 :z 2 [Atomic ratio], y 1 / x 1 y 2 / x 2 preferably greater than y 1 / x 1 y 2 / x 2 It is more than 1.5 times higher than More preferably, y 1 / x 1 y 2 / x 2 More preferably, y 1 / x 1 y 2 / x 2 In this case, in the oxide semiconductor film 336b, y 1 x 1 In the above case, a transistor including the oxide semiconductor film has stable electrical characteristics. However, y 1 x 1 When the oxide semiconductor Since the field effect mobility of the transistor using the film is reduced, 1 x 1 Less than three times It is preferable that:

[0302] For example, the oxide semiconductor film 336a may be formed of In:Ga:Zn=1:1:1, In:Ga:Z In-Ga-Zn oxide with an atomic ratio of n=1:1:1.2 or 3:1:2 is used. In addition, the oxide semiconductor film 336b can be formed by using a compound semiconductor layer having a structure of In:Ga:Zn=1:3:n (where n is a number). 2 to 8), 1:6:m (m is an integer between 2 and 10), or 1:9:6 In the oxide semiconductor film 336, an In-Ga-Zn oxide having an atomic ratio of 1000 to 10000 can be used. The atomic ratios of the oxide semiconductor film 336a and the oxide semiconductor film 336b are calculated by subtracting the atomic ratios from the above-mentioned atomic ratios as errors. The ratio of Zn in the oxide semiconductor film 336a is 0.01 to 0.25. is preferably Ga or more, since CAAC-OS is easily formed.

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

[0304] The thickness of the oxide semiconductor film 336b is greater than or equal to 3 nm and less than or equal to 100 nm, preferably greater than or equal to 3 nm and less than or equal to 50 nm. 0 nm or less.

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

[0306] Note that the oxide semiconductor film 336a and the oxide semiconductor film 336b each have an amorphous structure. region, microcrystalline region, polycrystalline region, CAAC-OS region, and single crystal region. The mixed film may have two or more kinds of materials. The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, The structure region, the polycrystalline structure region, the CAAC-OS region, and the single-crystalline structure region are either In some cases, the mixed film has a single layer structure with one or more regions of an amorphous structure. region, microcrystalline region, polycrystalline region, CAAC-OS region, and single crystal region. There are cases where the layer structure includes two or more of these regions.

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

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

[0309] Note that the oxide semiconductor film 336a and the oxide semiconductor film 336b are simply stacked. The energy of the bottom of the conduction band changes continuously between the layers. In other words, trap centers and recrystallization are formed at the interfaces of the films. The layer structure is designed so that there are no impurities that would form defect levels such as a combination center. Impurities are mixed between the stacked oxide semiconductor films 336a and 336b. When the interface is in a non-uniform state, the continuity of the energy band is lost, and carriers are trapped at the interface. They will recombine and disappear.

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

[0311] In FIG. 16, the multilayer film 336 is made up of an oxide semiconductor film 336a and an oxide semiconductor film 33 However, an oxide semiconductor film 336a is formed between the insulating film 306 and the oxide semiconductor film 336b. A three-layer structure may be formed by providing a film similar to the semiconductor film 336b. In this case, the insulating film 306 and The thickness of the oxide film provided between the oxide semiconductor film 336a and the oxide semiconductor film 336b is The thickness of the oxide film is preferably 1 nm or more and 5 nm or less, more preferably 1 nm or more and 3 nm or less. By setting the value to m or less, it is possible to reduce the amount of variation in the threshold voltage of the transistor. .

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

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

[0314] The oxide semiconductor film is an oxide semiconductor having a single crystal structure (hereinafter referred to as a single crystal oxide semiconductor), A polycrystalline oxide semiconductor (hereinafter referred to as a polycrystalline oxide semiconductor) and a microcrystalline oxide 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 an amorphous oxide semiconductor film. The oxide semiconductor may be composed of a semiconductor having a crystal grain and a crystal structure. The AAC-OS and a microcrystalline oxide semiconductor will be described.

[0315] First, we will explain the CAAC-OS film.

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

[0317] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a ferromagnetic microscope, clear boundaries between the crystals, i.e., crystal boundaries, were observed. It is not possible to confirm the grain boundary. It can be said that the AC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

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

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

[0320] FIG. 17(a) is a cross-sectional TEM image of the CAAC-OS film. FIG. 17(b) is a cross-sectional TEM image of the CAAC-OS film. This is a cross-sectional TEM image of 7(a) enlarged, with the atomic arrangement emphasized for ease of understanding. It is displayed.

[0321] FIG. 17(c) shows the area surrounded by a circle (diameter approximately 4n m) are local Fourier transform images. From Fig. 17(c), it is clear that the c-axis orientation is In addition, the orientation of the c-axis is different between the AO and O-A' sections, so different gradients are observed. In addition, the c-axis angles between the A and A are 14.3° and 16.6°. 26.4°, and so on. Similarly, O-A' Between these, the c-axis angle changes gradually and continuously from -18.3° to -17.6° to -15.9°. It is clear that the

[0322] When electron diffraction was performed on the CAAC-OS film, spots (bright spots) indicating orientation were observed. For example, a potential difference of 1 nm to 30 nm is measured on the top surface of the CAAC-OS film. When electron diffraction using a sagittal beam (also called nanobeam electron diffraction) is performed, spots are observed. (See FIG. 18(A)).

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

[0324] Most of the crystals in the CAAC-OS film are cubes with sides less than 100 nm. Therefore, the crystal part 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, 5 nm, or 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 More than 5μm 2 More than or equal to 1000μm 2 In some cases, crystal regions having more than this size may be observed.

[0325] X-ray diffraction (XRD) was performed on the CAAC-OS film. For example, InGaZnO 4 CAAC-OS film with crystals In the out-of-plane analysis, a peak was observed at a diffraction angle (2θ) of approximately 31°. This peak may appear in InGaZnO 4 It is assigned to the (009) plane of the crystal of This indicates that the crystals in the CAAC-OS film have a c-axis orientation, and the c-axis is generally aligned on the surface on which the film is formed or on the upper surface. It can be seen that it is oriented in a substantially vertical direction.

[0326] On the other hand, in-plane X-ray irradiation is performed on the CAAC-OS film in a direction perpendicular to the c-axis. In the analysis by the ane method, a peak may appear at 2θ around 56°. This peak is , InGaZnO 4 It is attributed to the (110) plane of the InGaZnO crystal. 4 Single crystal oxidation of 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, the 2θ is set to 5 Even when the φ is fixed at around 6° and scanned, no clear peak appears.

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

[0328] The crystalline portion is formed when the CAAC-OS film is formed or when a crystallization process such as a heat treatment is performed. As described above, the c-axis of the crystal is aligned along the surface on which the CAAC-OS film is formed or along the surface on which the CAAC-OS film is formed. The orientation of the CAAC-OS film is parallel to the normal vector of the top surface. When the shape of the CAAC-OS film is changed by etching, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed. Or it may not be parallel to the normal vector of the upper surface.

[0329] Furthermore, the distribution of c-axis oriented crystal parts in the CAAC-OS film does not need to be uniform. For example, the crystals in the CAAC-OS film grow from the top surface of the CAAC-OS film. When the crystal is formed by the above method, the region near the top surface has more 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 impurities. The doped region changes and regions with different proportions of c-axis oriented crystals are formed. This sometimes happens.

[0330] In addition, InGaZnO 4 Out-of-plane synthesis of CAAC-OS films with crystallites In the analysis by , in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ of around 36° may be due to the c-axis orientation in some parts of the CAAC-OS film. The CAAC-OS film contains crystals that do not have a 2θ of around 31°. It is preferred that the spectrum exhibits a peak and does not exhibit a peak at 2θ of around 36°.

[0331] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. The impurities include hydrogen, carbon, and The elements are other than the main components of the oxide semiconductor film, such as silicon and transition metal elements. The elements that bond to oxygen more strongly than the metal elements that form the oxide semiconductor film, such as arsenic, are oxidized. By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide have an atomic radius of Since the molecular radius is large, when the cation is contained in the oxide semiconductor film, the The impurities in the oxide semiconductor film may cause the atomic arrangement to be disturbed, which may result in a decrease in crystallinity. Objects can act as carrier traps or carrier generation sources.

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

[0333] A material with a low impurity concentration and a low defect level density (few oxygen vacancies) is called a high-purity intrinsic or The term "substantially high-purity intrinsic" refers to a highly-purified intrinsic oxide semiconductor film. Since the carrier generation source is small, the carrier density can be reduced. A transistor using an oxide semiconductor film has electrical characteristics in which the threshold voltage is negative ( 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 small 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 charge is long and can behave like a fixed charge. In addition, a transistor using an oxide semiconductor film having a high density of defect states has unstable electrical characteristics. There are cases.

[0334] In addition, the electrical characteristics of transistors using CAAC-OS films were improved by irradiation with visible light or ultraviolet light. The fluctuation is small.

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

[0336] In the microcrystalline oxide semiconductor film, crystal parts can be clearly seen in the TEM image. The crystal parts contained in the microcrystalline oxide semiconductor film may have a size of 1 nm or more and 100 nm or less. In particular, the size of the particles is between 1 nm and 10 nm. Nanocrystals (nc) are microcrystals with a diameter of 1 nm or less and 3 nm or less. The oxide semiconductor film having Al was formed by The nc-OS film is called a TE semiconductor film. In the M image, the grain boundaries may not be clearly visible.

[0337] The nc-OS film is a microscopic region (e.g., a region of 1 nm to 10 nm, especially a region of 1 nm or more). The atomic arrangement has periodicity in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystal parts. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis method, the nc-OS film may be indistinguishable from an amorphous oxide semiconductor film. For example, an XRD apparatus that uses X-rays with a diameter larger than that of the crystal part for an nc-OS film may be used. When the structure was analyzed using the out-of-plane method, the crystal plane was not 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 In addition, nanobeam electron diffraction was performed on the nc-OS film. In some cases, a bright area with a circular shape (ring shape) may be observed. When nanobeam electron diffraction was performed on the -OS film, multiple spots were observed within the ring-shaped region. (See FIG. 18(B)).

[0338] The nc-OS film is an oxide semiconductor film that has higher order than an amorphous oxide semiconductor film. Therefore, the nc-OS film has a lower density of defect states than the amorphous oxide semiconductor film. In the nc-OS film, there is no regularity in the crystal orientation between different crystal parts. The S film has a higher density of defect states than the CAAC-OS film.

[0339] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, or a CA The AC-OS film may be a laminate film having two or more kinds of films.

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

[0341] FIG. 18C shows an electron gun chamber 70, an optical system 72 below the electron gun chamber 70, and a A sample chamber 74, an optical system 76 below the sample chamber 74, an observation chamber 80 below the optical system 76, and an observation chamber 80 and a film chamber 82 below the observation chamber 80. The diffraction measurement device is shown. The camera 78 is installed facing the inside of the observation chamber 80. The housing 82 may not be provided.

[0342] FIG. 18(D) shows the internal structure of the transmission electron diffraction measurement device shown in FIG. 18(C). Inside the transmission electron diffraction measurement device, electrons emitted from an electron gun installed in the electron gun chamber 70 The light is irradiated onto a material 88 placed in the sample chamber 74 via the optical system 72. The electrons are incident on a fluorescent screen 92 installed inside the observation chamber 80 via the optical system 76. On the plate 92, a pattern appears according to the intensity of the incident electrons, which is called a transmission electron diffraction pattern. can be measured.

[0343] The camera 78 is installed facing the fluorescent screen 92 and captures the pattern appearing on the fluorescent screen 92. A straight line passing through the center of the lens of the camera 78 and the center of the fluorescent screen 92 The angle between the upper surface of the fluorescent plate 92 and the light source 93 is, for example, 15° to 80°, or 30° to 70°. The smaller the angle, the smaller the image captured by the camera 78. However, if the angle is known in advance, the resulting transmission electron diffraction pattern will be significantly distorted. If a camera is used, it is possible to correct distortions in the obtained transmission electron diffraction pattern. In some cases, it may be acceptable to install the camera 78 in the film chamber 82. The fluorescent screen 9 may be installed in the chamber 82 so as to face the direction of incidence of the electrons 84. It is possible to capture a transmission electron diffraction pattern with little distortion from the back surface of 2.

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

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

[0346] For example, as shown in FIG. 18(D), the irradiation position of the nanobeam electron 84 on the material is By changing (scanning) the material, it is possible to observe how the structure of the material changes. In this case, if the material 88 is a CAAC-OS film, the circuit shown in FIG. If the material 88 is an nc-OS film, a fold pattern is observed. A diffraction pattern similar to the one shown in the figure is observed.

[0347] By the way, even if the material 88 is a CAAC-OS film, it may be partially composed of nc-OS film, etc. The same diffraction pattern may be observed. Therefore, the quality of the CAAC-OS film can be judged by The ratio of the area where the diffraction pattern of the CAAC-OS film is observed in a certain range (CAAC For example, a good quality CAAC-OS film can be expressed as In this case, the CAAC ratio is 50% or more, preferably 80% or more, and more preferably 90% or more. The diffraction pattern of the CAAC-OS film is different from that of the CAAC-OS film. The proportion of observed areas is denoted as the non-CAAC rate.

[0348] As an example, the film is deposited immediately after (denoted as-sputtered), or in an oxygen-containing atmosphere. The top surface of each sample with 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 / s for 60 s. The diffraction pattern was observed while scanning, and the observed diffraction pattern was recorded as a still image every 0.5 seconds. The CAAC conversion rate was derived by converting the electron beam. The nanobeam was used. The same measurement was performed on six samples. The average value of six samples was used for calculation.

[0349] The CAAC ratio in each sample is shown in Fig. 19(A). The AC ratio was 75.7% (non-CAAC ratio 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 the 450°C heat treatment than immediately after the film formation. In other words, the non-CAAC ratio is low due to heat treatment at high temperatures (e.g., 400°C or higher). In addition, in the case of heat treatment at temperatures below 500°C, It can be seen that a CAAC-OS membrane with a high CAAC content can be obtained.

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

[0351] 19(B) and 19(C) show the CAAC-O immediately after deposition and after heat treatment at 450° C. 19(B) and 19(C) are planar TEM images of the S film. It can be seen that the CAAC-OS film after the 0°C heat treatment has a more homogeneous film quality. It can be seen that the film quality of the CAAC-OS film is improved by the heat treatment at high temperature.

[0352] By using such a measurement method, it is possible to analyze the structure of oxide semiconductor films having multiple structures. This may be the case.

[0353] 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.

[0354] (Embodiment 6) As described in Embodiment 2, 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 be low. The retention time can be made longer, and the write interval can also be set longer.

[0355] In the liquid crystal display device of this embodiment, a transistor with a low off-state current is used, The liquid crystal display device can perform display by at least two driving methods (modes). The drive mode is a conventional method for driving liquid crystal displays, in which data is written sequentially for each frame. The second driving mode is a driving method in which the data is written and then switched to the This is a driving method that stops rewriting of data. This is the motion mode.

[0356] The display of moving images is performed in the first driving mode. The display of still images is performed in the second driving mode. Since the data does not change, 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.

[0357] In addition, the liquid crystal element applied to the liquid crystal display device of the present embodiment has a large-area capacitance element. Therefore, the amount of charge stored in the capacitance element is large. It is possible to reduce the refresh rate and apply a driving mode that reduces the refresh rate. In the case where a driving mode that reduces the refresh rate is applied to the liquid crystal display device, However, since it is possible to suppress the change in the voltage applied to the liquid crystal layer for a long period of time, Therefore, it is possible to reduce the power consumption and to prevent the perception of image flicker caused by the The display quality can be improved.

[0358] Here, the effect of reducing the refresh rate will be described.

[0359] There are two types of eye fatigue: nervous fatigue and muscular fatigue. Nervous fatigue occurs when you use your eyes for a long time. By continuing to look at the light-emitting or flashing screen of an LCD display, the brightness of the screen can irritate the retina, nerves, and brain. Muscular fatigue is caused by the ciliary muscles, which are used to adjust the focus. It tires the flesh by overworking it.

[0360] FIG. 20(A) is a schematic diagram showing a display of a conventional liquid crystal display device. As shown above, the image on a conventional LCD display 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. This could cause eye fatigue.

[0361] In one embodiment of the present invention, a transistor having an extremely low off-state current, e.g., For example, a transistor using an oxide semiconductor is used. This makes it possible to suppress leakage of the charge stored in the capacitance element. Therefore, even if the frame frequency is lowered, the brightness of the liquid crystal display device can be maintained.

[0362] That is, as shown in FIG. 20(B), for example, an image can be rewritten once every five seconds. This allows the user to see the same image as much as possible, and reduces 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. is reduced.

[0363] According to one embodiment of the present invention, a liquid crystal display device that is gentle on the eyes can be provided.

[0364] 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.

[0365] (Embodiment 7) In this embodiment, a structural example of an electronic device to which a 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.

[0366] The display module 8000 shown in FIG. 21 is made up of an upper cover 8001 and a lower cover 8002. In between, touch panel 8004 is connected to FPC8003, and touch panel 8005 is connected to FPC8005. Display panel 8006, backlight unit 8007, frame 8009, printed circuit board 8010 and a battery 8011. In some cases, the read / write head 8011, the touch panel 8004, etc. may not be provided.

[0367] The display device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0368] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel 8 The shape and dimensions can be changed appropriately to match the size of 006.

[0369] The touch panel 8004 is a resistive or capacitive touch panel, and the display panel 8 8006. In addition, the opposing substrate (sealing substrate) of the display panel 8006 It is also possible to provide the display panel 8 with a touch panel function. It is also possible to provide an optical sensor in each pixel of the touch panel to make it an optical touch panel. Alternatively, a touch sensor electrode is provided in each pixel of the display panel 8006 to form a capacitive touch panel. It is also possible to use a channel.

[0370] The backlight unit 8007 includes a light source 8008. It may be provided at the end of the unit 8007 and may be configured to use a light diffusion plate.

[0371] 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 plate 8009 may function as a heat sink.

[0372] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal, and a clock signal. The power supply circuit is supplied with power from an external commercial power source. Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0373] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may be added.

[0374] FIG. 22 is an external view of an electronic device including a display device of one embodiment of the present invention.

[0375] Examples of electronic devices include television sets (also known as televisions or television receivers). (hereinafter referred to as "computer monitors"), digital cameras, digital video cameras, and other cameras digital photo frames; mobile phones (also called mobile phones or mobile phone devices); Examples include game machines, mobile information terminals, audio playback devices, and large game machines such as pachinko machines. do.

[0376] FIG. 22A shows a portable information terminal, which includes a main body 1001, a housing 1002, a display unit 100 The display unit 1003b is a touch panel. The screen can be operated by touching keyboard buttons 1004 displayed on the display unit 1003b. Of course, the display unit 1003a can be configured as a touch panel. The transistor described in the above embodiment may be used as a switching element in a liquid crystal panel. By fabricating an organic light-emitting panel and applying it to the display units 1003a and 1003b, It is possible to provide a highly useful portable information terminal.

[0377] The portable information terminal shown in FIG. 22(A) displays various information (still images, videos, text images, etc. ), calendar, date or time display function, The ability to manipulate or edit the information displayed, and to process it using various software (programs) In addition, the rear and side of the housing can have external connection terminals ( It may also be configured to include an earphone jack, a USB terminal, a recording medium insertion portion, etc.

[0378] The portable information terminal shown in FIG. 22(A) can also be configured to transmit and receive information wirelessly. You can wirelessly purchase and download the desired book data from the electronic book server. It is also possible to configure it in this way.

[0379] FIG. 22B shows a portable music player. The main body 1021 has a display unit 1023 and an earphone. A fixing part 1022 for mounting, a speaker, an operation button 1024, and an external memory slot The transistor shown in the above embodiment is used as a switching element. By manufacturing a liquid crystal panel or an organic light-emitting panel as a display unit 1023, This makes the portable music player more reliable.

[0380] Furthermore, the portable music player shown in FIG. 22(B) has an antenna, a microphone function, and a wireless function. In addition, by linking it with a mobile phone, you can enjoy wireless hands-free driving while driving a passenger car. Conversation by telephone is also possible.

[0381] FIG. 22C shows a mobile phone, which is composed of two housings, a housing 1030 and a housing 1031. The housing 1031 includes a display panel 1032, a speaker 1033, a microphone, and the like. 1034, a pointing device 1036, a camera 1037, and an external connection terminal 1038 The housing 1030 also includes a solar cell 1040 for charging the mobile phone, The external memory slot 1041 is also provided. The antenna is internally mounted inside the housing 1031. The transistor described in the above embodiment is applied to the display panel 1032. This makes it possible to provide a highly reliable mobile phone.

[0382] The display panel 1032 is equipped with a touch panel, and an image is displayed on the display panel 1032 as shown in FIG. A plurality of operation keys 1035 are shown by dotted lines. It also includes a boost circuit to boost the voltage required for each circuit.

[0383] The display direction of the display panel 1032 changes appropriately depending on the usage mode. A camera 1037 is provided on the same surface as the camera 1032, so video calls are possible. The speaker 1033 and microphone 1034 are not limited to voice calls, but can also be used for video calls, recording, playback, etc. Furthermore, the housing 1030 and the housing 1031 can be slid to each other, as shown in FIG. ) can be folded up into a compact size suitable for carrying around. It is possible to achieve this.

[0384] The external connection terminal 1038 can be connected to various cables such as AC adapters and USB cables. It is capable of charging and data communication with a personal computer, etc. A recording medium can be inserted into the memory slot 1041 to accommodate the storage and transfer of larger amounts of data. do.

[0385] In addition to the above functions, even if the device has infrared communication function, TV reception function, etc. good.

[0386] FIG. 22D shows an example of a television device. The television device 1050 includes: A display unit 1053 is built into the housing 1051. The display unit 1053 displays images. In addition, the CPU is built into the stand 1055 that supports the housing 1051. The transistor described in the above embodiment is applied to the display portion 1053 and the CPU. This makes it possible to provide a highly reliable television device 1050.

[0387] The television device 1050 can be operated using an operation switch provided on the housing 1051 or a separate remote control. The remote control can be operated by a remote controller. A display unit for displaying information output from the device may be provided.

[0388] The television device 1050 is configured to include a receiver, a modem, and the like. It can receive more general television broadcasts, and can also be connected to a modem via wired or wireless connection. By connecting to a network, communication can be one-way (sender to receiver) or two-way. It is also possible to communicate information (between a sender and a receiver, or between receivers).

[0389] The television device 1050 also includes an external connection terminal 1054 and a storage medium playback / recording unit 10 52, an external memory slot. An external connection terminal 1054 is provided for connecting a USB cable, etc. It can be connected to various cables, enabling data communication with a personal computer, etc. In the storage medium playback / recording unit 1052, a disk-shaped recording medium is inserted and recorded on the recording medium. It is possible to read data stored in the external memory and write data to the recording medium. Displays images and videos stored in the external memory 1056 inserted in the slot. It is also possible to display it on the display unit 1053.

[0390] In addition, when the off-leak current of the transistor described in the above embodiment is extremely small, By applying this transistor to the external memory 1056 and the CPU, power consumption is sufficiently reduced. This results in a highly reliable television apparatus 1050 with reduced noise.

[0391] 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. [Explanation of symbols]

[0392] 11 Pixel section 13 pixels 13_1 Pixel 13_2 pixels 14 subpixels 14B subpixel 14B_1 subpixel 14B_2 subpixel 14G subpixel 14G_1 subpixel 14G_2 subpixel 14R subpixel 14R_1 subpixel 14R_2 subpixel 14W_1 subpixel 14W_2 subpixel 16 Signal line driver circuit 17 Scan Lines 17_1 Scan line 17_2 Scan line 17_3 Scan line 18 Potential generation circuit 19 Capacitance Line 25 Signal Line 25_1 Signal line 25_2 Signal line 25_3 Signal line 31 Liquid crystal element 41 Light emitting element 43 Transistor 45 Transistor 47 Wiring 49 Wiring 50 Wiring 51 Gate insulating film 53 Inorganic insulating film 53a Insulating film 70 Electron Gun Room 72 Optical system 74 Sample Room 76 Optical system 78 Camera 80 Observation Room 82 Film Room 84 electronic 88 Substance 92 Fluorescent Screen 100 display device 102 Transistor 102a Transistor 103 Transistor 103a Transistor 103d Transistor 105 Capacitive element 302 Substrate 304a Conductive film 304b Conductive film 304c conductive film 304d conductive film 305 Insulating film 306 Insulating film 307 Oxide Semiconductor Film 308a Oxide semiconductor film 308b Oxide semiconductor film 308c metal oxide film 308d Oxide semiconductor film 308e Oxide semiconductor film 308f metal oxide film 309 Conductive Film 310a Conductive film 310b Conductive film 310c conductive film 310d conductive film 310e conductive film 310f conductive film 310g conductive film 310h conductive film 310i conductive film 310j conductive film 311 Insulating film 311a Insulating film 311b Insulating film 312 Insulating film 312a Insulating film 312b Insulating film 313 Insulating film 314 Insulating film 315 Conductive Film 316a Conductive film 316b Conductive film 316d Conductive film 316e Conductive film 317 Organic insulating film 317a Organic insulating film 318 Conductive Film 319 Conductive Film 319a Conductive film 319b Conductive film 320 Orientation Film 321 Liquid crystal layer 322 Liquid crystal element 336 Multilayer film 336a Oxide semiconductor film 336b Oxide semiconductor film 342 Substrate 344 Light-shielding film 346 Colored film 348 Insulating Film 350 Conductive Film 352 Orientation Film 362 Opening 364a opening 364b opening 364c opening 364d opening 371 Organic resin film 373 EL layer 375 Common electrode 1001 Main unit 1002 Case 1003a Display section 1003b Display section 1004 Keyboard Buttons 1021 Main unit 1022 Fixed part 1023 Display section 1024 operation buttons 1025 external memory slot 1030 Case 1031 Case 1032 Display Panel 1033 Speaker 1034 Microphone 1035 Operation Key 1036 Pointing Device 1037 Camera 1038 External connection terminal 1040 Solar Cell 1041 External memory slot 1050 Television Equipment 1051 Case 1052 Storage media playback and recording unit 1053 Display section 1054 External connection terminal 1055 Stand 1056 External Memory 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8007 Backlight unit 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

1. a first pixel having first to fourth sub-pixels, and a second pixel having fifth to eighth sub-pixels provided in a row next to the first pixel; the first and fifth sub-pixels are arranged in the same column and control light of the same color; the second and sixth sub-pixels are arranged in the same column and control light of the same color; the third, fourth, seventh and eighth sub-pixels are arranged in the same column, the third and eighth subpixels control light of the same color; the fourth and seventh sub-pixels control light of the same color; the first and fifth subpixels are always electrically connected to a first signal line; the second, fourth and sixth sub-pixels are always electrically connected to a second signal line; the third, seventh and eighth subpixels are always electrically connected to a third signal line; The gates of the transistors of the first to third subpixels are always electrically connected to a first scan line; The gates of the transistors of the fourth and eighth subpixels are always electrically connected to a second scan line; A display device, wherein gates of the transistors of the fifth to seventh subpixels are always electrically connected to a third scan line.

2. In claim 1, the first to third scanning lines extend in a row direction in a plan view, The display device, wherein the second scanning line has an area located between the first scanning line and the third scanning line in the plan view.

Images