Display device

Abstract

To provide a liquid crystal display device with an increased pixel aperture ratio, a liquid crystal display device that displays an image with high contrast and high luminance.SOLUTION: A liquid crystal display device comprises a first pixel electrode, a second pixel electrode, a transistor, a capacitor, a first insulating film, a second insulating film, and a third insulating film. The transistor includes a gate electrode, a gate insulating film, a first oxide semiconductor film, a source electrode, and a drain electrode. One of a pair of electrodes of the capacitor includes a second oxide semiconductor film. The first insulating film is provided over the first oxide semiconductor film, the second insulating film is provided over the second oxide semiconductor film such that the second oxide semiconductor film is sandwiched between the first insulating film and the second insulating film, and the third insulating film overlaps with an end of the first pixel electrode. The second pixel electrode is provided over the third insulating film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a liquid crystal display device or an electronic device using the liquid crystal display device. In particular, the present invention relates to a reflective liquid crystal display device. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or One aspect of the present invention relates to a composition of matter. The present invention relates to a display device, an electronic device, a manufacturing method thereof, or a driving method thereof. [Background technology]

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

[0003] In recent years, metal oxides that exhibit semiconductor properties have been used in transistors instead of silicon semiconductors. In this specification, metal oxides that exhibit semiconductor properties are referred to as oxides. For example, zinc oxide or In-Ga- A transistor using a Zn-based oxide is manufactured, and the transistor is used as a pixel switch of a display device. Techniques for use in chip elements and the like have been disclosed (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 Summary of the Invention [Problem to be solved by the invention]

[0005] One embodiment of the present invention is to provide a liquid crystal display device including a conductive oxide semiconductor film. Another object of one embodiment of the present invention is to provide a liquid crystal display device with an increased pixel aperture ratio. Another object of one embodiment of the present invention is to provide a display image having a high contrast. Another object of the present invention is to provide a liquid crystal display device that has high image quality and displays bright images. An object of one embodiment of the present invention is to provide a novel liquid crystal display device or the like.

[0006] The description of these problems does not preclude the existence of other problems. It is not necessary for one embodiment to solve all of these problems. The subject matter will be self-evident from the description, drawings, claims, etc. It is possible to extract other issues from the drawings, claims, etc. [Means for solving the problem]

[0007] One aspect of the present invention is a liquid crystal display device including a first pixel electrode, a second pixel electrode, and a second pixel electrode electrically connected to the first pixel electrode. a transistor to be connected; a capacitance element electrically connected to the transistor; and a first insulating a liquid crystal display device having a film, a second insulating film, and a third insulating film, The gate electrode includes a gate insulating film provided in contact with the gate electrode, and a gate insulating film provided in contact with the gate insulating film. a first oxide semiconductor film provided so as to overlap with a gate electrode; a source electrode and a drain electrode electrically connected to the oxide semiconductor film, One of the pair of electrodes includes a second oxide semiconductor film, and the first insulating film includes a first oxide semiconductor film. The second insulating film is formed on the insulating film, and the second oxide semiconductor film is formed between the first insulating film and the second insulating film. The third insulating film is provided on the second oxide semiconductor film so as to be sandwiched between the first insulating film and the second oxide semiconductor film. The first pixel electrode is provided on the edge of the first insulating film, and the second pixel electrode is provided on the third insulating film. The liquid crystal display device is characterized in that

[0008] The third insulating film and the second pixel electrode overlap each other so that their ends are generally aligned with each other. The above liquid crystal display device is also one embodiment of the present invention.

[0009] The liquid crystal display device further includes a first colored film and a second colored film, and the first colored film is disposed on the first pixel electrode. The liquid crystal display device also includes a second colored film provided on the second pixel electrode. This is one aspect of the invention.

[0010] In addition, one embodiment of the present invention is a liquid crystal display device including a first pixel electrode, a second pixel electrode, a conductive film, and a first pixel electrode. a transistor electrically connected to the element electrode; and a capacitance element electrically connected to the transistor. a first insulating film, a second insulating film, and a third insulating film. The transistor includes a gate electrode, a gate insulating film provided in contact with the gate electrode, and a gate insulating film. a first oxide semiconductor layer provided in contact with the gate insulating film and overlapping the gate electrode; a source electrode and a drain electrode electrically connected to the first oxide semiconductor film; one of a pair of electrodes of the capacitor includes a second oxide semiconductor film, and the first insulating film is The second insulating film is provided on the first oxide semiconductor film, and the second insulating film is formed so that the second oxide semiconductor film is not covered by the first insulating film. the insulating film is provided on the second oxide semiconductor film so as to be sandwiched between the insulating film and the second insulating film, The third insulating film has a region overlapping with the second pixel electrode and the conductive film, and the conductive film overlaps with the first pixel electrode. The liquid crystal display device is characterized in that the light-emitting element is electrically connected to an electrode.

[0011] The third insulating film is provided on the first pixel electrode and the second pixel electrode, and the conductive film is The above liquid crystal display device provided over the third insulating film is also one embodiment of the present invention.

[0012] The first pixel electrode and the third insulating film are provided on the conductive film, and the second pixel electrode is The above liquid crystal display device provided over the third insulating film is also one embodiment of the present invention.

[0013] The conductive film has a region overlapping with the second pixel electrode via the third insulating film. A liquid crystal display device is also one embodiment of the present invention.

[0014] The liquid crystal display device according to the present invention further includes a capacitor element having a first pixel electrode and a second pixel electrode. This is one aspect of the invention.

[0015] The transistor is provided so as to overlap with the first insulating film and the first oxide semiconductor film. and a second oxide semiconductor film formed on the first oxide semiconductor film. .

[0016] In the liquid crystal display device, the first oxide semiconductor film and the second oxide semiconductor film In-M-Zn oxide (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or or Hf).

[0017] In the liquid crystal display device, the first insulating film contains oxygen and the second insulating film contains hydrogen. It is preferred that the compound contains:

[0018] Also, a device having the above liquid crystal display device, a switch, a speaker, a display unit or a housing is provided. The child device is also an aspect of the present invention. [Effects of the Invention]

[0019] According to one embodiment of the present invention, a liquid crystal display device including a conductive oxide semiconductor film is provided. According to one embodiment of the present invention, a liquid crystal display device with an increased aperture ratio can be provided. Alternatively, according to one embodiment of the present invention, the contrast of a displayed image can be high, or A liquid crystal display device that displays a bright image can be applied. This makes it possible to provide a novel liquid crystal display device.

[0020] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. The above will be made clear from the description, drawings, claims, etc. It is possible to extract other effects from the descriptions in the aspects and claims. [Brief explanation of the drawings]

[0021] [Figure 1] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 2] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 3] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 4] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a liquid crystal display device. [Figure 5] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a liquid crystal display device. [Figure 6]1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a liquid crystal display device. [Figure 7] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a liquid crystal display device. [Figure 8] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a liquid crystal display device. [Figure 9] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 10] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 11] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 12] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 13] 1A and 1B are a top view illustrating one embodiment of a liquid crystal display device and a circuit diagram illustrating one embodiment of a pixel. [Figure 14] FIG. 1 is a top view illustrating one embodiment of a liquid crystal display device. [Figure 15] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 16] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 17] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 18] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 19] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 20] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 21] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 22] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 23] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 24] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 25] FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal display device. [Figure 26] Cs-corrected high-resolution TEM image of a cross section of CAAC-OS, and a schematic cross-sectional diagram of CAAC-OS. [Figure 27] Cs-corrected high-resolution TEM image of the CAAC-OS in the plane. [Figure 28] 10A and 10B illustrate structural analyses of a CAAC-OS and a single-crystal oxide semiconductor by XRD. [Figure 29] Electron diffraction pattern of CAAC-OS. [Figure 30] FIG. 1 shows the change in the crystalline part of an In-Ga-Zn oxide due to electron irradiation. [Figure 31] 1A to 1C illustrate a method for forming a CAAC-OS film. [Figure 32] A diagram explaining the InMZnO4 crystal. [Figure 33] 1A to 1C illustrate a method for forming a CAAC-OS film. [Figure 34] 1A and 1B are a top view and a cross-sectional view illustrating an example of a transistor. [Figure 35] FIG. 1 is a cross-sectional view illustrating an example of a transistor. [Figure 36] FIG. 1 is a diagram illustrating a band structure. [Figure 37] FIG. 1 is a cross-sectional view illustrating an example of a transistor. [Figure 38] FIG. 1 is a top view illustrating a structure of a display device. [Figure 39] FIG. 2 is a top view illustrating a configuration of a pixel arranged in a display device. [Figure 40] FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a display device. [Figure 41] FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a first display portion of the display device. [Figure 42] FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a second display portion of the display device. [Figure 43] FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a display device. [Figure 44] FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a first display portion of the display device. [Figure 45] FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a second display portion of the display device. [Figure 46] 1A to 1C illustrate electronic devices. [Figure 47] 1A to 1C illustrate electronic devices. [Figure 48] 10A and 10B are diagrams showing display results of a liquid crystal display device according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. One embodiment is not limited to the following description, and the present invention may be modified without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various changes in form and details may be made. One aspect of the invention should not be construed as being limited to the description of the following embodiment. In the embodiments described below, the same parts or parts having similar functions are referred to as The same symbols or hatch patterns are used in common among different drawings, and their repetition The explanation will be omitted.

[0023] In each drawing described in this specification, the size of each component, the thickness of the film, or the area is not clearly indicated. The figures may be exaggerated for clarity and are not necessarily limited to that scale. .

[0024] In addition, ordinal numbers such as first and second used in this specification are used in order to avoid confusion of elements. It is not intended to limit the number of items. The terms "second" or "third" can be used interchangeably to explain the present invention.

[0025] In addition, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the term "conductive layer" can be changed to the term "conductive film." Alternatively, for example, the term "insulating film" may be changed to "insulating layer" It may be possible to change the term to

[0026] In this specification, the term "the ends are roughly aligned" means that the ends do not completely overlap, but are aligned in the upper direction. This includes a layer being located inside a lower layer, and an upper layer being located outside a lower layer.

[0027] In addition, even when the term "semiconductor" is used in this specification, for example, a material having electrical conductivity is also included. If the dielectric constant is low enough, it may have the properties of an "insulator." The boundary between "insulator" and "insulator" is vague and it may not be possible to strictly distinguish them. The term "semiconductor" in the above may be replaced with "insulator." The term "insulator" in the specification etc. may be replaced with "semiconductor." In some cases, the term "insulator" used in this specification can be rephrased as "semi-insulator." .

[0028] In addition, even when the term "semiconductor" is used in this specification, for example, a material having electrical conductivity is also included. If the electrical conductivity is sufficiently high, it may have the properties of a "conductor." The boundary between "conductor" and "electroconductor" is vague and it may not be possible to strictly distinguish them. The term "semiconductor" in the above may be replaced with "conductor." The term "conductor" in the specification etc. may be replaced with "semiconductor" in some cases.

[0029] The functions of the "source" and "drain" of a transistor are different for transistors of different polarities. When using a current source, or when the direction of the current changes during circuit operation, For this reason, in this specification, the terms "source" and "drain" are used interchangeably. It can be used as such.

[0030] In this specification, patterning refers to the use of a photolithography process. However, the patterning is not limited to the photolithography process. It is also possible to use a process other than the photolithography process. The mask shall be removed after the etching process.

[0031] In this specification and the like, a silicon oxynitride film is a film containing more oxygen than nitrogen as a component. It refers to a film with a high content of oxygen, preferably 55 atomic % to 65 atomic % and 100 atomic % of nitrogen. % or more and 20 atomic % or less, silicon is 25 atomic % or more and 35 atomic % or less, hydrogen is 0.1 atomic % or more The silicon nitride oxide film is a film containing silicon dioxide in a range of 10 atomic % or more. The composition of the film is such that the nitrogen content is higher than the oxygen content, and preferably the nitrogen content is 55 atomic % or more. 5 atomic % or less, oxygen is 1 atomic % to 20 atomic % and silicon is 25 atomic % to 35 atomic % % or less, and hydrogen is contained in a concentration range of 0.1 atomic % to 10 atomic %.

[0032] (Embodiment 1) In this embodiment, a liquid crystal display device of one embodiment of the present invention will be described with reference to FIGS. Reveal.

[0033] <Configuration example of liquid crystal display device> FIG. 1A is a top view of a liquid crystal display device according to one embodiment of the present invention, and FIG. 1B is a top view of a liquid crystal display device according to one embodiment of the present invention. A) corresponds to the cross-sectional view of the cut surface between the dashed dotted line AB and the dashed dotted line CD. In FIG. 1A, in order to avoid complication, some of the components of the liquid crystal display device are shown. In the top view of the transistor, the gate insulating film and other components are omitted. In the subsequent drawings, as in FIG. 1(A), some of the components may be omitted. do.

[0034] The dashed line AB in FIG. 1A indicates the channel length direction of the transistor 150. The dashed line CD indicates the channel width direction of the transistor 150. In this case, the channel length direction of the transistor is the direction from the source (source region or source electrode) The direction in which carriers move between the drain and the diode (drain region or drain electrode) is called the The channel width direction is perpendicular to the channel length direction in a plane parallel to the substrate. It means direction.

[0035] The liquid crystal display device shown in FIGS. 1A and 1B includes a transistor including a first oxide semiconductor film 110. The capacitor 160 includes a transistor 150 and a capacitor element 160 including an insulating film between a pair of electrodes. In the element 160, one of the pair of electrodes is the second oxide semiconductor film 111. The other pole is the conductive film 120 .

[0036] The transistor 150 includes a gate electrode 104 on a substrate 102 and a gate electrode 106 on the gate electrode 104. The insulating film 108 functions as a gate insulating film, and the gate electrode 104 on the insulating film 108 overlaps the insulating film 108. The first oxide semiconductor film 110 is located at a position where the source electrode 111 is formed. In other words, the transistor 150 has a first the first oxide semiconductor film 110 and a gate insulating film provided in contact with the first oxide semiconductor film 110. an insulating film 108 that functions as a film; a first oxide semiconductor film that is provided in contact with the insulating film 108; The gate electrode 104 is provided at a position overlapping with the first oxide semiconductor film 110. The source electrode 112a and the drain electrode 112b are electrically connected to the The transistor 150 shown in FIGS. 1A and 1B has a so-called bottom-gate structure.

[0037] In addition, on the transistor 150, more specifically, the first oxide semiconductor film 110, the source Insulating films 114, 116, 118, and 119 are formed on the electrode 112a and the drain electrode 112b. The insulating films 114, 116, and 118 serve as protective insulating films for the transistor 150. The insulating film 119 functions as a planarization film. , 116, 118, and 119 are formed with openings 143 that reach the drain electrode 112b. A conductive film 120 is formed on the insulating film 119 so as to cover the opening 143. That is, the conductive film 120 is electrically connected to the transistor 150. It functions as a pixel electrode for a display device.

[0038] The capacitor 160 is a first electrode that functions as one of a pair of electrodes over the insulating film 116. The second oxide semiconductor film 111 and the second oxide semiconductor film 112 function as a dielectric film on the second oxide semiconductor film 111. Insulating films 118 and 119, and the second oxide semiconductor film 111 via the insulating films 118 and 119. a conductive film 120 that functions as the other electrode of the pair of electrodes at the overlapping position; That is, the conductive film 120 functions as a pixel electrode and as an electrode of a capacitor element. do.

[0039] The transistor 150, the capacitor 160, and the conductive film 120 shown in FIGS. Thus, one pixel of the liquid crystal display device can be formed.

[0040] The insulating film 130 is provided on the end of the conductive film 120. A conductive film 121 is provided. The conductive film 121 is formed on a substrate including a transistor 150, for example. It functions as a pixel electrode for the pixel and the adjacent pixel.

[0041] The conductive film 120 and the conductive film 121 are insulated from each other by the insulating film 130. As a result, the gap between the conductive film 120 and the conductive film 121 can be eliminated in the top view. With such a structure, the liquid crystal display device of one embodiment of the present invention can increase the aperture ratio of a pixel. In addition, by increasing the aperture ratio of the pixels, the contrast of the displayed image can be increased. Furthermore, a reflective liquid crystal display device can be provided that displays bright images.

[0042] In addition, since the conductive film 121 is provided on the insulating film 130, the conductive film 121 and the common electrode (not shown) (hereinafter also referred to as inter-electrode distance) The distance between the electrodes can be made shorter than the distance between the electrodes. A liquid crystal element is formed by a pixel electrode and a common electrode sandwiching a layer (not shown) having a crystal. The common electrode is provided with a common potential for each pixel. Layers (e.g. R (red), G (green), B (blue), or R, G, B, Y (yellow) etc.) for pixels If there is a color layer of a specific color, shorten (or lengthen) the distance between the electrodes of the pixel having the color layer of the specific color. The color tone of the displayed image can be adjusted.

[0043] In FIG. 1B, the insulating film 130 and the conductive film 121 are generally aligned at their edges. As shown in FIG. 2(A), the insulating film 11 is provided so as to overlap with the insulating film 11. However, the present invention is not limited to this. The insulating film 130 is provided only near the end of the conductive film 120 so as to cover the end of the conductive film 120. In addition, the liquid crystal display device shown in FIGS. The conductive film 120 and the conductive film 121 overlap each other through the insulating film 130. 21 may not have an overlapping area.

[0044] Furthermore, the insulating film 119 in the liquid crystal display device of one embodiment of the present invention has a surface with unevenness. The unevenness on the surface of the insulating film 119 shown in FIG. The conductive film 120 and the conductive film 1 Since the insulating film 119 is provided on the conductive film 119, the texture structure of the insulating film 119 is 20 and the surface of the conductive film 121. As a result, light incident on these conductive films is diffusely reflected. However, the conductive film 120 and the conductive film 121 appear to be generally white when viewed macroscopically. By controlling the orientation of the liquid crystal using the polarized light, the contrast of the reflective liquid crystal display device can be improved. The insulating film 130 may have a textured surface. stomach.

[0045] The thickness of the insulating film 119 is determined according to the capacitance value required for the capacitor element 160 in the liquid crystal display device. The thickness can be adjusted as appropriate. Alternatively, the insulating film 119 may not be provided. 3A shows an example of a cross-sectional view of a liquid crystal display device that does not have the insulating film 119. The insulating film 118 functions as a dielectric film of the capacitance element 160 .

[0046] Note that in the liquid crystal display device shown in FIG. 3A, the second oxide semiconductor film 111 is formed over the insulating film 116. The second oxide semiconductor film 111a is formed at the same time as the second oxide semiconductor film 111. By simultaneously depositing and etching the film, it is designed to overlap with the channel region of the transistor. For example, the second oxide semiconductor film 111a may be formed by 11 are deposited and etched at the same time, and are formed at the same time, so they have the same material. Therefore, it is possible to suppress an increase in the number of process steps. One embodiment is not limited to this. It may be formed in a different process from that of the body membrane 111.

[0047] The second oxide semiconductor film 111a is a first oxide semiconductor film that serves as a channel region of the transistor 150. Therefore, the second oxide semiconductor film 11 1a functions as the second gate electrode of the transistor 150. The second oxide semiconductor film 111a may be connected to the gate electrode 104. Alternatively, The second oxide semiconductor film 111a is not connected to the gate electrode 104. A signal or a potential different from that of the transistor 1 shown in FIG. The transistor 50 has a so-called double gate structure. At this time, the gate electrode for the second gate electrode can be improved. The insulating film becomes insulating films 114 and 116 .

[0048] The transistor 150 includes the second oxide semiconductor film 111a and the gate electrode 104. The transistor 150 shown in FIG. 3(B) differs from the transistor 150 shown in FIG. 3(B) in that it does not have the gate electrode 104. The transistor shown in FIG. 1 has a so-called top-gate structure, and the second oxide semiconductor film 111a It functions as a first gate electrode.

[0049] Note that the first oxide semiconductor film 110 functions as a channel region of the transistor 150. The second oxide semiconductor film 111 is used as one of a pair of electrodes of the capacitor 160. Therefore, the second oxide semiconductor film 11 functions as a gate insulating film rather than the first oxide semiconductor film 110. The first oxide semiconductor film 110 and the second oxide semiconductor film 111 have low resistivity. It is preferable that the first oxide semiconductor film 110 and the second oxide semiconductor film 111 contain the same metal element. By configuring the film 111 to have the same metal element, it is possible to It is possible to share the same equipment (processing equipment, etc.), which reduces manufacturing costs. .

[0050] In addition, a wiring formed of a separate metal film or the like may be connected to the second oxide semiconductor film 111. For example, when the liquid crystal display device shown in FIG. 1 is used for a transistor and a capacitor in a pixel portion, In this case, the lead wiring or gate wiring is formed of a metal film, and the second oxide semiconductor is formed on the metal film. Alternatively, a structure may be used in which the lead wiring or gate wiring is connected to the substrate 111. By forming it as a film, it is possible to reduce wiring resistance, thereby suppressing signal delays, etc. It is possible.

[0051] Note that the insulating film 118 provided over the transistor 150 and used for the capacitor 160 An insulating film containing at least hydrogen is used as the insulating film for the transistor 150. The insulating film 107 and the insulating films 114 and 116 provided on the transistor 150 include: An insulating film containing at least oxygen is used. 60, and an insulating film used over the transistor 150 and the capacitor 160. By using the insulating film having the above structure, the first oxide semiconductor of the transistor 150 The resistivity of the conductive film 110 and the second oxide semiconductor film 111 of the capacitor 160 is controlled. It is possible.

[0052] In addition, an insulating film used in the capacitor 160, and the transistor 150 and the capacitor 160 By configuring the insulating film used on the conductive film 120 as follows, Specifically, the insulating films 114 and 116 are formed by the first oxide film. The insulating film 118 is formed on the second oxide semiconductor film 111. The insulating film 118 is sandwiched between the insulating film 116 and the second oxide semiconductor film 111. As a result, openings are formed in the insulating films 114 and 116 at positions overlapping with the second oxide semiconductor film 111. The resistivity of the second oxide semiconductor film 111 can be controlled without providing a gate electrode. By using this structure, the conductive film 120 and the conductive film 121 can be formed in the liquid crystal display device shown in FIGS. This allows the liquid crystal formed on the conductive film 121 to have good alignment.

[0053] In the transistor 150, the first oxide semiconductor film 110 serves as a channel region. Since the second oxide semiconductor film 111 is used as the second oxide semiconductor film 112, the second oxide semiconductor film 111 has a higher resistivity than the second oxide semiconductor film 111. The oxide semiconductor film 111 functions as an electrode. It has a relatively low resistivity.

[0054] Here, the resistivity of the first oxide semiconductor film 110 and the second oxide semiconductor film 111 can be controlled by The method will be explained below.

[0055] <Method for controlling resistivity of oxide semiconductor film> Acids that can be used for the first oxide semiconductor film 110 and the second oxide semiconductor film 111 The oxide semiconductor film has resistance due to oxygen deficiency and / or impurity concentration such as hydrogen and water in the film. The first oxide semiconductor film 110 is a semiconductor material whose resistivity can be controlled. and treatment for increasing oxygen vacancies and / or the impurity concentration in the second oxide semiconductor film 111; By selecting a treatment that reduces oxygen deficiency and / or impurity concentration, The resistivity of the nitride semiconductor film can be controlled.

[0056] Specifically, the second oxide semiconductor film 111 functioning as an electrode of the capacitor 160 The oxide semiconductor film is subjected to plasma treatment to increase oxygen vacancies in the oxide semiconductor film. and / or by increasing impurities such as hydrogen and water in the oxide semiconductor film. An oxide semiconductor film having high carrier density and low resistivity can be obtained. An insulating film containing hydrogen is formed in contact with the conductor film, and the insulating film containing hydrogen, for example, the insulating film 118 By diffusing hydrogen from the oxide semiconductor film into the oxide semiconductor film, the carrier density is increased and the resistivity is low. The second oxide semiconductor film 111 can be an oxide semiconductor film. Before the process of increasing oxygen vacancies or diffusing hydrogen, After this step, the film has a function as a conductor.

[0057] On the other hand, the first oxide semiconductor film 110 functioning as a channel region of the transistor 150 By providing the insulating films 107, 114, and 116, the insulating films 106 and 116 containing hydrogen are At least one of the insulating films 107, 114, and 116 contains oxygen. In other words, by using an insulating film that can release oxygen, the first oxide Oxygen can be supplied to the oxide semiconductor film 110. The oxide semiconductor film 110 becomes an oxide semiconductor film with high resistivity because oxygen vacancies in the film or at the interface are filled. The insulating film capable of releasing oxygen may be, for example, a silicon oxide film or A silicon oxynitride film can be used.

[0058] In order to obtain an oxide semiconductor film with low resistivity, an ion implantation method, an ion doping method, etc. , plasma immersion ion implantation method, etc. Nitrogen or nitrogen may be implanted into the oxide semiconductor film.

[0059] In order to obtain an oxide semiconductor film with low resistivity, the oxide semiconductor film is subjected to plasma treatment. For example, the plasma treatment may be carried out using a rare gas (He, Ne, A Plasma using gas containing one or more selected from the group consisting of r, Kr, Xe), hydrogen, and nitrogen. More specifically, plasma treatment under an Ar atmosphere, a mixture of Ar and hydrogen, Plasma treatment under a mixed gas atmosphere, plasma treatment under an ammonia atmosphere, and plasma treatment under Ar and ammonia Plasma treatment in a mixed gas atmosphere of nia or plasma treatment in a nitrogen atmosphere Examples include:

[0060] By the plasma treatment, the oxide semiconductor film is formed into a lattice from which oxygen is desorbed (or The oxygen vacancies may become a cause of carrier generation. In addition, in the vicinity of the oxide semiconductor film, more specifically, in the area below or When hydrogen is supplied from the insulating film in contact with the upper side, the oxygen vacancies and hydrogen combine to form the oxygen vacancies. In some cases, electrons are generated as carriers.

[0061] On the other hand, an oxide semiconductor film in which oxygen vacancies are filled and the hydrogen concentration is reduced can be made highly purified and intrinsic. Alternatively, it can be said that the oxide semiconductor film is substantially highly purified and made intrinsic. The carrier density of the oxide semiconductor film is 8×10 11 pieces / cm 3 Less than 1 x 10 1 1 pieces / cm 3 less than 1×10 10 pieces / cm 3 High An oxide semiconductor film that is pure intrinsic or substantially highly pure intrinsic has a small number of carrier generation sources. Therefore, the carrier density can be reduced. Since the oxide semiconductor film has a low density of defect states, the density of trap states can be reduced. can.

[0062] In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a significantly low off-state current. Very small, with a channel width of 1×10 6 Even if the device has a channel length of 10 μm, When the voltage between the source electrode and the drain electrode (drain voltage) is in the range of 1V to 10V, The current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1×10 -13 A and below Therefore, the above-mentioned high purity pure or substantially high purity pure can be obtained. The first oxide semiconductor film 110a is used as a channel region. The transistor 150 has small variations in electrical characteristics and is highly reliable.

[0063] The insulating film 118 may be, for example, an insulating film containing hydrogen, in other words, capable of releasing hydrogen. The second oxide semiconductor film 111 can be formed by using a suitable insulating film, typically a silicon nitride film. The insulating film capable of releasing hydrogen is one containing Hydrogen concentration is 1×10 22 atoms / cm 3 It is preferable that the insulating film is more than or equal to this. By forming the second oxide semiconductor film 111 in contact with the second oxide semiconductor film 111, As a result, hydrogen can be contained in the first oxide semiconductor film 110 and the second oxide semiconductor film 111. By changing the configuration of the insulating film in contact with the oxide semiconductor film 111 of 2, The insulating film 106 can be made of the same material as the insulating film 118. By using silicon nitride as the insulating film 106, The released oxygen is supplied to the gate electrode 104, thereby preventing oxidation.

[0064] The hydrogen contained in the oxide semiconductor film reacts with oxygen that is bonded to metal atoms to form water. The oxygen vacancies are formed in the lattice from which oxygen is desorbed (or in the portions from which oxygen is desorbed). When hydrogen enters the electron carrier, it can generate electrons. By bonding with oxygen, which bonds with metal atoms, electrons, which act as carriers, may be generated. Therefore, the second oxide semiconductor film 111 provided in contact with the insulating film containing hydrogen The second oxide semiconductor film has a higher carrier density than the first oxide semiconductor film 110.

[0065] The first oxide semiconductor film 110 in which the channel region of the transistor 150 is formed is Specifically, the first oxide semiconductor film 110 Secondary Ion Mass Spectrometry (SIMS) The hydrogen concentration obtained by spectrometry was calculated as 2×10 20 atoms / cm 3 Less than or equal to 5 x 10 19 atoms / cm 3 Less than or equal to 1×10 19 atoms / cm 3 Below, 5 x 10 18 atoms / cm 3 Less than 1 x 10 1 8 atoms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 Below, further Preferably 1 x 10 16 atoms / cm 3 The following applies.

[0066] On the other hand, the second oxide semiconductor film 111 functioning as an electrode of the capacitor 160 is formed of the first oxide semiconductor film. The oxide semiconductor film 110 has a higher hydrogen concentration and / or oxygen vacancy and a lower resistivity than the oxide semiconductor film 110. The second oxide semiconductor film 111 is a conductive film. The hydrogen concentration in the second oxide semiconductor film 111 is 8×10 19 That's all, Preferably 1 x 10 20 atoms / cm 3 More preferably, 5 × 10 20 That's all. In addition, the second oxide semiconductor film 111 contains less oxide than the first oxide semiconductor film 110. The hydrogen concentration in the second oxide semiconductor film 1 is 2 times or more, preferably 10 times or more. The resistivity of the oxide semiconductor film 11 is 1×10 -8 1×10 times more - 1 It is preferably less than 1×10 -3 Ωcm or more 1×10 4 Ωcm not yet More preferably, the resistivity is less than 1×10 -3 Ωcm or more 1×10 -1 Less than Ωcm It is good.

[0067] Here, other components of the liquid crystal display device shown in FIGS. 1(A) and 1(B) will be described in detail. The following is an explanation of this.

[0068] <Substrate> There is no particular restriction on the material of the substrate 102, but it should be strong enough to withstand the subsequent heat treatment. For example, glass substrates, ceramic substrates, quartz substrates, and A fire substrate or the like may be used as the substrate 102. Also, silicon or silicon carbide may be used. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, and compound semiconductor substrates such as silicon germanium It is also possible to apply an SOI substrate, etc., and a semiconductor element is provided on such a substrate. A glass substrate may be used as the substrate 102. In this case, 6th generation (1500mm x 1850mm), 7th generation (1870mm x 2200mm) m), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 2800m By using large area substrates such as 10th generation (2950mm x 3400mm), In addition, a flexible substrate is used as the substrate 102, and a display device having a flexible The transistor 150, the capacitor element 160, etc. may be formed directly on the conductive substrate.

[0069] In addition to these, various substrates can be used as the substrate 102 to form transistors. The type of substrate is not limited to a specific one. Plastic substrate, metal substrate, stainless steel substrate, stainless steel foil Substrate with tungsten foil, tungsten substrate, substrate with tungsten foil, flexible substrate, Examples include laminated films, paper containing fibrous materials, and base films. Glass substrates Examples of such glass include barium borosilicate glass, aluminoborosilicate glass, and soda glass. An example of a flexible substrate is polyethylene terephthalate (PE T), polyethylene naphthalate (PEN), and polyethersulfone (PES) are typical examples. These include plastics that can be used for bonding, and flexible synthetic resins such as acrylic. Examples of the film include polypropylene, polyester, polyvinyl fluoride, or poly Examples of base films include polyamide, polyimide, inorganic vapor In particular, semiconductor substrates, single crystal substrates, SOI substrates, etc. By manufacturing a transistor using This allows the manufacture of small-sized transistors with low power consumption and high current capability. When a circuit is constructed using such transistors, it is possible to reduce the power consumption of the circuit or to increase the integration density of the circuit. It is possible to achieve this.

[0070] It is also possible to form a transistor using a certain substrate and then transfer the transistor to another substrate. The transistor may be placed on one of the substrates to which the transistor is transferred. Examples include substrates on which the above-mentioned transistors can be formed, as well as paper substrates, ceramic substrates, and the like. Fan substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, hemp), synthetic fibers (nylon) , polyurethane, polyester) or regenerated fiber (acetate, cupra, rayon, These substrates include recycled polyester, leather substrates, and rubber substrates. By using this, it is possible to form transistors with good characteristics and low power consumption. This allows for the manufacture of devices that are less likely to break, heat resistant, lightweight, or thin.

[0071] <First Oxide Semiconductor Film and Second Oxide Semiconductor Film> The first oxide semiconductor film 110 and the second oxide semiconductor film 111 are made of at least indium. Aluminum (In), zinc (Zn) and metals (Al, Ti, Ga, Y, Zr, La, Ce, Sn or It is preferable that the film contains a film represented by In-M-Zn oxide containing a metal such as Hf. In addition, in order to reduce variations in the electrical characteristics of transistors using the oxide semiconductor, Both preferably include a stabilizer.

[0072] The stabilizer includes the metals described above under M, for example, gallium (Ga), silicon (Si), and the like. Sn, hafnium (Hf), aluminum (Al), or zirconium (Zr) Other stabilizers include lanthanum (La), a lanthanide. , Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium ( Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0073] The oxide semiconductors constituting the first oxide semiconductor film 110 and the second oxide semiconductor film 111 Examples of the oxides include In-Ga-Zn oxides, In-Al-Zn oxides, and In-Sn- Zn-based oxide, In-Hf-Zn-based oxide, In-La-Zn-based oxide, In-Ce-Z n-based oxides, In-Pr-Zn-based oxides, In-Nd-Zn-based oxides, In-Sm-Zn oxides, In-Eu-Zn oxides, In-Gd-Zn oxides, In-Tb-Zn oxides Oxides, In-Dy-Zn oxides, In-Ho-Zn oxides, In-Er-Zn oxides oxides, In-Tm-Zn oxides, In-Yb-Zn oxides, In-Lu-Zn ​​oxides In-Sn-Ga-Zn oxides, In-Hf-Ga-Zn oxides, In-Al- Ga-Zn oxide, In-Sn-Al-Zn oxide, In-Sn-Hf-Zn oxide In—Hf—Al—Zn-based oxides can be used.

[0074] Here, the In-Ga-Zn oxide refers to an oxide having In, Ga, and Zn as its main components. The ratio of In, Ga, and Zn does not matter. Metal elements other than n may be included.

[0075] The first oxide semiconductor film 110 and the second oxide semiconductor film 111 are made of the above oxide. The first oxide semiconductor film 110 and the second oxide semiconductor film 111 may contain the same metal element. By using the same metal element for the compound semiconductor film 111, the manufacturing cost can be reduced. For example, using a metal oxide target with the same metal composition reduces manufacturing costs. In addition, by using a metal oxide target with the same metal composition, it is possible to The etching gas or etching solution can be commonly used when processing the nitride semiconductor film. However, the first oxide semiconductor film 110 and the second oxide semiconductor film 111 may be formed from the same material. Even if they contain the same metal elements, the composition may differ. For example, transistors and capacitors During the manufacturing process of the semiconductor, metal elements in the film may be released, resulting in a different metal composition.

[0076] When the first oxide semiconductor film 110 is an In-M-Zn oxide, the atoms of In and M are The atomic ratio of In is preferably 2 when the sum of In and M is 100 atomic %. 5 atomic % or more, M is less than 75 atomic %, and more preferably In is 34 atomic % or more atomic % or higher and M is less than 66 atomic %.

[0077] The first oxide semiconductor film 110 has an energy gap of 2 eV or more, preferably 2.5 eV or more. eV or more, more preferably 3 eV or more. By using a nitride semiconductor, the off-state current of the transistor 150 can be reduced.

[0078] The thickness of the first oxide semiconductor film 110 is 3 nm to 200 nm, preferably 3 nm. The thickness is set to 100 nm or more, and more preferably 3 nm or more and 50 nm or less.

[0079] The first oxide semiconductor film 110 is an In-M-Zn oxide (wherein M is Al, Ga, Y, Zr, or L In the case of In-Mn-Zn oxides (In, Ce, or Nd), the sputtering The atomic ratio of the metal elements in the ring target preferably satisfies In≧M, Zn≧M. The atomic ratio of the metal elements in such a sputtering target is In:M:Zn= 1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=3:1:2, In:M In:M:Zn=1:3:4, In:M:Zn=1:3:6, etc. The atomic ratios of the oxide semiconductor films 110 in each of the above sputtering conditions are taken into account as errors. This includes a variation of plus or minus 40% in the atomic ratio of the metal elements contained in the get.

[0080] As the first oxide semiconductor film 110, an oxide semiconductor film with low carrier density is used. For example, the first oxide semiconductor film 110 has a carrier density of 1×10 17 pieces / cm 3 below, Preferably 1 x 10 15 pieces / cm 3 or less, more preferably 1 × 10 13 pieces / cm 3 below , more preferably 1 × 10 11 pieces / cm 3 The following oxide semiconductor film is used.

[0081] However, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use an appropriate composition depending on the required properties (e.g., the mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of the transistor, the carrier density of the first oxide semiconductor film 110 is The impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. are appropriately adjusted. It is preferable to set the following.

[0082] The first oxide semiconductor film 110 contains silicon or carbon, which is one of the Group 14 elements. If the oxide semiconductor film 110 is mixed with the oxygen, oxygen vacancies in the first oxide semiconductor film 110 increase, causing the first oxide semiconductor film 110 to become n-type. Therefore, the concentrations of silicon and carbon in the first oxide semiconductor film 110 (secondary ion mass (concentration obtained by analytical method) is 2 x 10 18 atoms / cm 3 Below, preferably 2x 10 17 atoms / cm 3 The following applies.

[0083] In addition, the first oxide semiconductor film 110 is subjected to secondary ion mass spectrometry. The concentration of alkaline metals or alkaline earth metals is 1×10 18 atoms / cm 3 Below, good Preferably 2 x 10 16 atoms / cm 3 The following are alkali metals and alkaline earth metals: When metals bond with oxide semiconductors, they may generate carriers, which can increase the off-state current of transistors. Therefore, the alkali metal of the first oxide semiconductor film 110 may be increased. Alternatively, it is preferable to reduce the concentration of alkaline earth metals.

[0084] Furthermore, when nitrogen is contained in the first oxide semiconductor film 110, electrons serving as carriers are generated. As a result, the carrier density increases and the oxide semiconductor containing nitrogen becomes more easily n-type. Therefore, a transistor using the oxide semiconductor tends to be normally on. In the film, it is preferable that nitrogen is reduced as much as possible, for example, secondary ion mass The nitrogen concentration obtained by the analytical method is 5 x 10 18 atoms / cm 3 It is preferable to I wish.

[0085] The first oxide semiconductor film 110 may have, for example, a non-single-crystal structure. For example, CAAC-OS (C Axis Aligned-Crystal ine Oxide Semiconductor), polycrystalline structure, microcrystalline structure, or Among non-single crystal structures, the amorphous structure has the highest defect level density and CA AC-OS has the lowest defect level density.

[0086] The first oxide semiconductor film 110 may have, for example, an amorphous structure. For example, the atomic arrangement of the membrane is disordered and does not have a crystalline component. The oxide film has, for example, a completely amorphous structure and does not have any crystalline portions.

[0087] Note that the first oxide semiconductor film 110 may have an amorphous structure, a microcrystalline structure, a polycrystalline structure, or a polycrystalline structure. The film was a mixed film having two or more of the following structures: a region of a crystalline structure, a region of a CAAC-OS structure, and a region of a single crystal structure. The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, and a polycrystalline structure region. The crystal structure may have two or more regions of either a CAAC-OS region or a single-crystal structure region. The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, and a polycrystalline structure region. , CAAC-OS, and single-crystal structure regions. This may be the case.

[0088] <Insulating film> The insulating films 106 and 107 functioning as gate insulating films of the transistor 150 are Plasma CVD (CVD: Chemical Vapor Deposition) method, By sputtering or the like, a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, Silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, dioxide film ZrO2 film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film Insulating films containing one or more of a cerium oxide film and a neodymium oxide film can be used. It is possible to form the insulating films 106 and 107 not as a laminated structure but as a single film selected from the above-mentioned materials. A layer insulating film may also be used.

[0089] The insulating film 106 functions as a blocking film that suppresses oxygen permeation. , the insulating films 107, 114, 116 and / or the first oxide semiconductor film 110 contain excess acid. When oxygen is supplied, the insulating film 106 can suppress oxygen permeation.

[0090] Note that the first oxide semiconductor film 110 functioning as a channel region of the transistor 150 The insulating film 107 in contact with the It is more preferable to have a region containing excess oxygen (oxygen excess region). The insulating film 107 is an insulating film capable of releasing oxygen. To provide the excess region, for example, the insulating film 107 may be formed in an oxygen atmosphere. Alternatively, oxygen may be introduced into the insulating film 107 after it has been formed to form an oxygen-excess region. The methods include ion implantation, ion doping, and plasma immersion ion implantation. , plasma treatment, etc. can be used.

[0091] Furthermore, when hafnium oxide is used for the insulating films 106 and 107, the following effects are achieved. Hafnium oxide has a higher dielectric constant than silicon oxide and silicon oxynitride. Therefore, compared with silicon oxide, the thickness of the insulating films 106 and 107 can be made larger. This reduces the leakage current due to the channel current. Furthermore, hafnium oxide, which has a crystalline structure, can be used in amorphous It has a higher dielectric constant than hafnium oxide, which has a structure. Therefore, it has a small off-state current. To make a small transistor, it is preferable to use hafnium oxide having a crystalline structure. Examples of the crystal structure include monoclinic and cubic systems. An embodiment is not limited to these.

[0092] In this embodiment, a silicon nitride film is formed as the insulating film 106, and the insulating film 107 The silicon nitride film has a lower dielectric constant than the silicon oxide film. The film thickness required to obtain the same capacitance as a silicon oxide film is large, so The insulating film 108 that functions as the gate insulating film of the transistor 150 includes a silicon nitride film. This makes it possible to physically thicken the insulating film. This prevents a voltage drop and improves the dielectric strength, thereby preventing electrostatic damage to the transistor 150. It is possible.

[0093] <Gate electrode, source electrode, and drain electrode> The gate electrode 104, the source electrode 112a, and the drain electrode 112b can be made of a material such as Materials that can be used include aluminum, titanium, chromium, nickel, copper, yttrium, and zirconium. Metals such as aluminum, molybdenum, silver, tantalum, or tungsten, or materials mainly composed of these The alloy containing aluminum can be used as a single layer or a laminated structure. Two-layer structure with titanium film laminated on tungsten film, two-layer structure with titanium film laminated on tungsten film , a two-layer structure with a copper film laminated on a molybdenum film, and an alloy film containing molybdenum and tungsten A two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film. Two-layer structure: titanium film or titanium nitride film and a layer on top of the titanium film or titanium nitride film An aluminum or copper film is laminated, and then a titanium or titanium nitride film is formed on top of that. The three-layer structure is a molybdenum film or molybdenum nitride film and a molybdenum film or molybdenum nitride film. An aluminum film or copper film is laminated on the molybdenum film, and a molybdenum film is then formed on top of that. Alternatively, there is a three-layer structure in which a molybdenum nitride film is formed. When the drain electrode 112b has a three-layer structure, the first and third layers are made of titanium and titanium nitride. Molybdenum, tungsten, alloys containing molybdenum and tungsten, molybdenum and zinc A film made of an alloy containing zinc or molybdenum nitride is formed, and the second layer is made of copper, aluminum, It is possible to form a film made of a low resistance material such as aluminum, gold or silver, or an alloy of copper and manganese. Indium tin oxide, indium oxide containing tungsten oxide, oxide Indium zinc oxide containing tungsten, indium oxide containing titanium oxide, titanium oxide Indium tin oxide containing tungsten, indium zinc oxide, indium doped with silicon oxide Alternatively, a light-transmitting conductive material such as silicon tin oxide may be used. Materials that can be used for the source electrode 112a and the drain electrode 112b include, for example, It can be formed by using a sputtering method.

[0094] <Conductive film> The conductive films 120 and 121 function as pixel electrodes. For example, a material that is reflective in visible light may be used. Aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt Metallic materials such as copper, palladium, or alloys containing these metallic materials can be used. In addition, lanthanum, neodymium, germanium, etc. may be added to the above metal materials or alloys. In addition, alloys of aluminum and titanium, alloys of aluminum and nickel , aluminum and neodymium alloys, aluminum, nickel, and lanthanum alloys (Al Alloys containing aluminum (aluminum alloys), such as (Ni-Ni-La), silver-copper alloys, silver and palladium-copper alloys (Ag-Pd-Cu, also written as APC), and silver-magnesium alloys. It can be formed using an alloy containing silver, such as gold. An alloy containing silver and copper has high heat resistance. Films made of the above materials can be used as a single layer or as a laminate. By laminating a metal film or a metal oxide film in contact with the aluminum alloy film, The oxidation of the gold film can be suppressed. The metal film and metal oxide film can be made of titanium, Titanium oxide and the like are examples.

[0095] <Protective insulating film> The insulating films 114, 116, and 118 function as protective insulating films for the transistor 150. is a silicon oxide film, silicon oxynitride film, etc., formed by plasma CVD method, sputtering method, etc. film, silicon nitride oxide film, silicon nitride film, aluminum oxide film, hafnium oxide film, acid yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film An insulating film containing one or more of a sodium film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film can be used, respectively.

[0096] In addition, the first oxide semiconductor film 110 serving as a channel region of the transistor 150 The insulating film 114 in contact with the substrate is preferably an oxide insulating film that can release oxygen. In other words, an insulating film capable of releasing oxygen is an insulating film having a stoichiometric composition. The insulating film has a region containing oxygen in excess of the insulating film (oxygen excess region). To provide an oxygen excess region in the insulating film 114, for example, the insulating film 114 is formed in an oxygen atmosphere. Alternatively, oxygen may be introduced into the insulating film 114 after it is formed to form an oxygen-excess region. The oxygen introduction method includes ion implantation, ion doping, plasma immersion, and The ion implantation method, plasma treatment, etc. can be used.

[0097] By using an insulating film capable of releasing oxygen as the insulating film 114, Oxygen is transferred to the first oxide semiconductor film 110 which functions as a channel region of the gate electrode 150. It is possible to reduce the amount of oxygen vacancies in the first oxide semiconductor film 110. For example, The surface temperature of the film measured by TDS analysis is 100°C. The amount of oxygen molecules released in the range of 700°C or 100°C or 500°C , 1.0×10 18 molecules / cm 3 By using the insulating film described above, the first oxide semiconductor film The amount of oxygen vacancies contained in 110 can be reduced.

[0098] Furthermore, it is preferable that the insulating film 114 has a small number of defects. The spin density of the signal at g=2.001 originating from the silicon dangling bond is 3 x 10 17 spins / cm 3 This is because the insulating film 114 is preferably If the density of defects is high, oxygen will be bonded to the defects, and the oxygen in the insulating film 114 will be reduced. In addition, the insulating film 114 and the first oxide semiconductor film 1 It is preferable that the number of defects at the interface with 10 is small. Typically, it is found by ESR measurement that The g value resulting from defects in the first oxide semiconductor film 110 is 1.89 or more and 1.96 or less. The signal spin density is 1×10 17 spins / cm 3 or below, and even below the detection limit It is preferable.

[0099] In the insulating film 114, all the oxygen that has entered the insulating film 114 from the outside is Alternatively, some of the oxygen that has entered the insulating film 114 from the outside may move to the outside. In some cases, oxygen may remain in the insulating film 114. In addition, oxygen may enter the insulating film 114 from the outside, and When oxygen contained in the insulating film 114 moves to the outside of the insulating film 114, The insulating film 114 may be made of an oxide film that can transmit oxygen. When the oxide insulating film is formed, oxygen desorbed from the insulating film 116 provided on the insulating film 114 can be transferred to the first oxide semiconductor film 110 through the insulating film 114.

[0100] The insulating film 114 is preferably formed using an oxide insulating film with a low density of nitrogen oxide states. Note that the density of the nitrogen oxide level can be determined by the energy level at the top of the valence band of the oxide semiconductor film. Energy (E V_OS) and the energy of the conduction band minimum of the oxide semiconductor film (E C_OS )and As the oxide insulating film, a film having a low nitrogen oxide release amount may be formed between the oxide insulating film and the film. Silicon oxynitride film or aluminum oxynitride film that emits less nitrogen oxide is used. You can be there.

[0101] In addition, a silicon oxynitride film that emits a small amount of nitrogen oxides can be analyzed by thermal desorption spectroscopy. This membrane releases more ammonia than nitrogen oxides, and typically releases ammonia. The amount of molecules released is 1×10 18 molecules / cm 3 5x10 or more 19 molecules / cm 3 The following is the The amount of ammonia released is determined when the surface temperature of the membrane is 50°C or higher and 650°C or lower, preferably 50°C or lower. The amount released by heat treatment at or above 550°C or below.

[0102] Nitrogen oxides (NO x , x is greater than 0 and less than or equal to 2, preferably greater than or equal to 1 and less than or equal to 2), typically NO2 or NO forms a level in the insulating film 114. The level is The insulating film 110 is located within the energy gap of the semiconductor film 110. When the oxide semiconductor layer 114 diffuses to the interface between the oxide semiconductor layer 114 and the first oxide semiconductor layer 110, the level is transferred to the insulating film 114 side. As a result, the trapped electrons may be trapped in the insulating film 114. and the first oxide semiconductor film 110. It shifts in the positive direction.

[0103] Nitrogen oxide reacts with ammonia and oxygen during heat treatment. The nitrogen oxide contained in the insulating film 116 reacts with the ammonia contained in the insulating film 116 during the heat treatment. Therefore, the nitrogen oxide contained in the insulating film 114 is reduced. Electrons are less likely to be trapped at the interface between the first oxide semiconductor film 110 and the second oxide semiconductor film 110.

[0104] By using the oxide insulating film as the insulating film 114, the threshold voltage of the transistor can be reduced. It is possible to reduce the shift in the electrical characteristics of the transistor. can.

[0105] Note that the heat treatment in the manufacturing process of a transistor is typically performed at a temperature lower than 400° C. or lower than 375° C. The insulating film 114 is heated to 1000° C. or less (preferably, 340° C. or more and 360° C. or less). In the spectrum obtained by ESR measurement below 0 K, the g value is 2.037 or more. a first signal of 9 or less, a second signal of g-value 2.001 or more and 2.003 or less, and A third signal with a g value between 1.964 and 1.966 is observed. The split width of the null and second signals, and the split width of the second and third signals The split width is about 5 mT in the X-band ESR measurement. The first signal is between 2.039 and 2.039, and the second signal is between 2.001 and 2.003. The sum of the spin densities of the signals and the third signal with g values ​​between 1.964 and 1.966 The total is 1 x 10 18 spins / cm 3 less than 1 × 10 17 spins / cm 3 More than 1×10 18 spins / cm 3 is less than.

[0106] In addition, the g value is between 2.037 and 2.039 in the ESR spectrum below 100K. The first signal has a g value of 2.001 or more and 2.003 or less, and the second signal has a g value of 1 The third signal, between 0.964 and 1.966, is nitrogen oxide (NO x , x is greater than 0 These correspond to signals caused by nitrogen oxides (<2 or less, preferably 1 to 2). Examples include nitrogen monoxide and nitrogen dioxide. That is, the g value is between 2.037 and 2.039. a first signal having a g value of 2.001 or more and 2.003 or less, and a second signal having a g value of The smaller the total spin density of the third signal between 1.964 and 1.966, the more acid This means that the content of nitrogen oxides contained in the oxide insulating film is low.

[0107] The oxide insulating film has a nitrogen concentration of 6×10 as measured by SIMS. 20 atoms / cm 3 The following is the result.

[0108] The substrate temperature is between 220℃ and 350℃, and PEC using silane and nitrous oxide is used. By forming the oxide insulating film using a VD method, a dense and hard film can be obtained. It can be formed.

[0109] The insulating film 116 formed in contact with the insulating film 114 is an oxygen film having a stoichiometric composition. The oxide insulating film is formed using an oxide insulating film containing more oxygen than the stoichiometric composition. When an oxide insulating film contains more oxygen than the stoichiometric composition, part of the oxygen is released by heating. Oxide insulating films containing more oxygen than the oxygen required for the composition were analyzed by thermal desorption spectroscopy (TDS). Thermal Desorption Spectroscopy (TDS) was used to measure the oxygen atoms. The converted oxygen release rate is 1.0 x 10 19 atoms / cm 3Above, preferably 3.0 x10 20 atoms / cm 3 The oxide insulating film is as described above. The surface temperature of the film is 100°C or more and 700°C or less, or 100°C or more and 500°C or less. A range is preferred.

[0110] Furthermore, it is preferable that the insulating film 116 has a small number of defects. The spin density of the signal at g=2.001 originating from the silicon dangling bond is 1.5 x 10 18 spins / cm 3 Less than or even 1×10 18 spins / cm 3 Below It is preferable that the insulating film 116 is thicker than the insulating film 114. Since it is separated from the semiconductor film 110 , it may have a higher defect density than the insulating film 114 .

[0111] The thickness of the insulating film 114 is 5 nm or more and 150 nm or less, preferably 5 nm or more and 50 nm or less. The thickness of the insulating film 116 can be set to 10 nm or less and preferably 30 nm or less. The thickness can be 30 nm or more and 500 nm or less, preferably 150 nm or more and 400 nm or less. Cut.

[0112] In addition, the insulating films 114 and 116 can be made of the same material, so that the insulating film In some cases, the interface between the film 114 and the insulating film 116 cannot be clearly seen. In this embodiment, the interface between the insulating film 114 and the insulating film 116 is shown by a broken line. In the embodiment, the two-layer structure of the insulating film 114 and the insulating film 116 has been described. However, the present invention is not limited to this, and examples thereof include a single layer structure of the insulating film 114, a single layer structure of the insulating film 116, and a three-layer structure. A laminated structure of more than one layer may also be used.

[0113] The insulating film 118 that functions as the dielectric film of the capacitance element 160 is a nitride insulating film. In particular, a silicon nitride film has a higher dielectric constant than a silicon oxide film, and is therefore preferable. Since the film thickness required to obtain the same capacitance as that of a silicon oxide film is large, the dielectric constant of the capacitance element 160 is The insulating film 118, which functions as a dielectric film, contains a silicon nitride film, which makes the insulating film physically Therefore, the decrease in the dielectric strength of the capacitance element 160 can be suppressed, and further The dielectric strength voltage can be improved, and electrostatic breakdown of the capacitance element 160 can be suppressed. The film 118 functions as an electrode of the capacitor element 160. It also has the function of reducing

[0114] The insulating film 118 also blocks oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. By providing the insulating film 118, the first oxide semiconductor film 110 the diffusion of oxygen from the insulating films 114 and 116 to the outside, This can prevent hydrogen, water, and the like from entering the first oxide semiconductor film 110 from the outside. Nitrogen, which has a blocking effect on oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. Instead of the oxide insulating film, an oxide insulating film that has a blocking effect on oxygen, hydrogen, water, etc. is set up. As the oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like, an oxide insulating film Aluminum, aluminum oxynitride, gallium oxide, gallium oxynitride, yttria Examples include yttrium oxide, yttrium oxynitride, hafnium oxide, and hafnium oxynitride.

[0115] The insulating film 119 having the function of a planarizing film may be, for example, a polyimide resin or an acrylic resin. resin, polyimide amide resin, benzocyclobutene resin, polyamide resin, epoxy resin Heat-resistant organic materials such as grease can be used.

[0116] The insulating film 130 can be formed using a material similar to that of the insulating film 119. The film 130 may be made of the same material as the insulating film 106 .

[0117] <Method for manufacturing a liquid crystal display device> Next, an example of a method for manufacturing the liquid crystal display device shown in FIGS. 1A and 1B will be described with reference to FIGS. 8 will be used to explain.

[0118] First, the gate electrode 104 is formed on the substrate 102. Then, the substrate 102 and the gate An insulating film 108 including insulating films 106 and 107 is formed on the electrode 104 (see FIG. 4(A)). .

[0119] The substrate 102, the gate electrode 104, and the insulating films 106 and 107 are made of the same material as described above. In this embodiment, the substrate 1 can be formed by selecting the material from the materials listed above. A glass substrate is used as the gate electrode 102, and a tungsten conductive film is used as the gate electrode 104. a silicon nitride film capable of releasing hydrogen is used as the insulating film 106; The insulating film 107 is a silicon oxynitride film that can release oxygen.

[0120] The gate electrode 104 is formed by depositing a conductive film on the substrate 102 so that a desired region of the conductive film remains. The pattern can be formed by patterning as shown above and then etching away unnecessary areas.

[0121] Next, the first oxide semiconductor film 11 is formed on the insulating film 108 at a position overlapping the gate electrode 104. 0 (see Figure 4(B)).

[0122] The first oxide semiconductor film 110 can be formed by selecting from the materials listed above. In this embodiment, the first oxide semiconductor film 110 is formed of In -Ga-Zn oxide film (In:Ga:Zn=1:1:1.2 metal oxide target was used) Use.) is used.

[0123] The first oxide semiconductor film 110 is formed by depositing an oxide semiconductor film over the insulating film 108. The oxide semiconductor film is patterned so that a desired region remains, and then unnecessary regions are etched away. It can be formed by

[0124] After the first oxide semiconductor film 110 is formed, heat treatment is preferably performed. °C or higher and 650 °C or lower, preferably 300 °C or higher and 500 °C or lower, more preferably 350 °C or higher At temperatures up to 450°C, inert gas atmosphere, atmosphere containing oxidizing gas at 10 ppm or more, Alternatively, the heat treatment may be carried out in a reduced pressure atmosphere. After the above, an oxidizing gas was supplied for 1 minute to compensate for oxygen released from the first oxide semiconductor film 110. The heat treatment may be performed in an atmosphere containing 0 ppm or more. 7 and removing impurities such as hydrogen and water from at least one of the first oxide semiconductor film 110. Note that the heat treatment can be performed before the first oxide semiconductor film 110 is processed into an island shape. You may go to.

[0125] Note that the transistor 150 having the first oxide semiconductor film 110 as a channel region is stable. In order to provide good electrical characteristics, impurities in the first oxide semiconductor film 110 are reduced, and the first It is effective to make the oxide semiconductor film 110 intrinsic or substantially intrinsic.

[0126] Next, a conductive film is formed over the insulating film 108 and the first oxide semiconductor film 110. The desired area is patterned to remain, and then the unnecessary area is etched away, A source electrode 112a and a drain electrode 112b are formed on the insulating film 108 and the first oxide semiconductor film 110. The pole 112b is formed (see FIG. 4(C)).

[0127] The source electrode 112a and the drain electrode 112b are made of the above-listed materials. In this embodiment, the source electrode 112a and The drain electrode 112b is made of a tungsten film, an aluminum film, and a titanium film. A three-layer laminated structure is used.

[0128] After the source electrode 112a and the drain electrode 112b are formed, the first oxide semiconductor The surface of the membrane 110 may be washed. For example, a chemical solution such as phosphoric acid may be used. By performing cleaning using a chemical solution such as phosphoric acid, the oxide semiconductor film 1 Impurities attached to the surface of 10 (for example, the source electrode 112a and the drain electrode 112b) However, this cleaning is not always necessary. In some cases, cleaning may not be necessary.

[0129] Also, the steps of forming the source electrode 112a and the drain electrode 112b and the above-mentioned washing In either one or both of the steps, the source electrode 11 of the first oxide semiconductor film 110 2a and the area exposed from the drain electrode 112b may be thinned.

[0130] Next, the insulating film 108, the first oxide semiconductor film 110, the source electrode 112a, and the drain electrode 112b are formed. The insulating films 114 and 116 are formed on the electrode 112b. Patterning is performed so that the desired area remains, and then unnecessary areas are etched away to create openings. 141 is formed (see FIG. 4(D)).

[0131] After the insulating film 114 is formed, the insulating film 116 is successively formed without exposure to the air. After the insulating film 114 is formed, it is preferable to control the flow rate, pressure, and temperature of the source gas without exposing the insulating film 114 to the atmosphere. By adjusting one or more of the frequency power and the substrate temperature, the insulating film 116 is continuously formed. The concentration of impurities derived from atmospheric components can be reduced at the interface between the insulating film 114 and the insulating film 116. At the same time, oxygen contained in the insulating films 114 and 116 is transferred to the first oxide semiconductor film 110. This allows oxygen to migrate, thereby reducing the amount of oxygen vacancies in the first oxide semiconductor film 110. This becomes possible.

[0132] In addition, in the step of forming the insulating film 116, the insulating film 114 is formed on the first oxide semiconductor film 110. Therefore, the first oxide semiconductor film 110 can be protected from damage while The insulating film 116 can be formed using high frequency power with a high power density.

[0133] The insulating films 114 and 116 can be formed by selecting from the materials listed above. In this embodiment, the insulating films 114 and 116 are made of a material that can release oxygen. A silicon oxynitride film that can be used is used.

[0134] After the insulating films 114 and 116 are formed, heat treatment (hereinafter referred to as first heat treatment) is performed. The first heat treatment is preferably performed to remove nitrogen oxides contained in the insulating films 114 and 116. Alternatively, the first heat treatment can reduce the amount of oxides in the insulating films 114 and 116. A part of the oxygen contained in the first oxide semiconductor film 110 is transferred to the first oxide semiconductor film 110. The amount of oxygen vacancies contained in 10 can be reduced.

[0135] The temperature of the first heat treatment is typically less than 400°C, preferably less than 375°C, and The first heat treatment is preferably performed at a temperature of 150° C. or higher and 350° C. or lower. Dry air (water content is 20 ppm or less, preferably 1 ppm or less, more preferably 10 ppm or less) The reaction may be carried out under an atmosphere of air (ppb or less) or a rare gas (argon, helium, etc.). It is preferable that the nitrogen, oxygen, ultra-dry air, or rare gas does not contain hydrogen, water, etc. The heat treatment may be performed using an electric furnace or RTA (Rapid Thermal Anneal). etc. can be used.

[0136] The opening 141 is formed so as to expose the drain electrode 112b. As a method for forming the openings, for example, a dry etching method can be used. The method for forming 41 is not limited to this, and may be a wet etching method or a dry etching method. The opening 14 may be formed by a combination of the etching method and the wet etching method. In the case where the thickness of the drain electrode 112b is reduced by the etching process for forming the drain electrode 112b, There is a match.

[0137] Next, a second oxide semiconductor film 111 is formed on the insulating film 116 so as to cover the opening 141. An oxide semiconductor film is formed (see FIGS. 5A and 5B).

[0138] Note that FIG. 5A shows the inside of a film formation apparatus when an oxide semiconductor film is formed over the insulating film 116. In FIG. 5(A), a sputtering device is used as the film forming device. The target 193 installed inside the sputtering device and the target 193 are The generated plasma 194 is shown schematically.

[0139] First, when forming an oxide semiconductor film, plasma is discharged in an atmosphere containing oxygen gas. At this time, oxygen is added to the insulating film 116, which is a surface where the oxide semiconductor film is to be formed. When forming an oxide semiconductor film, in addition to oxygen gas, an inert gas (e.g., helium For example, argon gas and xenon gas may be mixed. It is preferable to use oxygen gas and argon gas, and the flow rate of oxygen gas is greater than the flow rate of argon gas. By increasing the flow rate of oxygen gas, oxygen can be suitably added to the insulating film 116. For example, the oxide semiconductor film is formed under the conditions of: The ratio of is 50% or more and 100% or less, preferably 80% or more and 100% or less. .

[0140] In FIG. 5A, oxygen or excess oxygen added to the insulating film 116 is schematically shown. It is indicated by a dashed arrow.

[0141] The substrate temperature during the formation of the oxide semiconductor film is preferably room temperature or higher and lower than 340° C. Preferably, the temperature is from room temperature to 300°C, more preferably from 100°C to 250°C, and even more preferably The temperature is usually 100°C or higher and 200°C or lower. On the other hand, the substrate 102 is preferably a large glass substrate. When a substrate (for example, a sixth to tenth generation substrate) is used, the substrate for forming an oxide semiconductor film is If the plate temperature is set to 150° C. or higher and lower than 340° C., the substrate 102 will deform (distort or warp). Therefore, when a large glass substrate is used, it is difficult to form an oxide semiconductor film. By keeping the substrate temperature during film application between 100°C and 150°C, deformation of the glass substrate is suppressed. It is possible.

[0142] The oxide semiconductor film can be formed using a material selected from the materials listed above. In this embodiment, an In-Ga-Zn metal oxide target (In:Ga:Zn=1:3) :6 [atomic ratio]) by a sputtering method to form an oxide semiconductor film.

[0143] Next, the oxide semiconductor is processed into a desired shape to form an island-shaped second oxide semiconductor film 1 11 is formed (see FIG. 5(C)).

[0144] The second oxide semiconductor film 111 is formed by depositing an oxide semiconductor film over the insulating film 116 and then The semiconductor film is patterned so that the desired areas remain, and then the unwanted areas are etched away. This can be formed by:

[0145] Next, the insulating film 118 is formed over the insulating film 116 and the second oxide semiconductor film 111 ( See Figure 6(A)).

[0146] The insulating film 118 contains either hydrogen or nitrogen, or both. For example, a silicon nitride film is preferably used as the insulating film 118. For example, it can be formed by using a sputtering method or a PECVD method. When the insulating film 118 is formed by the PECVD method, the substrate temperature is set to be less than 400° C., preferably 375° C. The temperature is preferably less than 180° C., and more preferably 180° C. or more and 350° C. or less. In this case, it is preferable to set the substrate temperature within the above range, since a dense film can be formed. By setting the substrate temperature in the above range when forming the insulating film 118, the insulating films 114 and 1 Oxygen or excess oxygen in the oxide semiconductor film 16 can be transferred to the first oxide semiconductor film 110. become.

[0147] After the insulating film 118 is formed, a heat treatment similar to the first heat treatment described above (hereinafter, In this manner, the second oxide semiconductor film 111 is formed. When the oxide semiconductor film is formed, oxygen is added to the insulating film 116, and then the insulating film 116 is heated at a temperature lower than 400° C., preferably. The heat treatment is preferably performed at a temperature of 180°C or higher and 350°C or lower. By this treatment, oxygen or excess oxygen in the insulating film 116 is transferred into the first oxide semiconductor film 110. By this movement, oxygen vacancies in the first oxide semiconductor film 110 can be filled.

[0148] Here, oxygen moving into the first oxide semiconductor film 110 will be described with reference to FIG. FIG. 7 shows the substrate temperature (typically less than 375° C.) during the formation of the insulating film 118, or A second heat treatment (typically below 375° C.) after the formation of film 118 causes the first oxide 7 is a model diagram showing oxygen moving into the semiconductor film 110. In FIG. Oxygen (oxygen radicals, oxygen atoms, or oxygen molecules) moving into the semiconductor film 110 is indicated by the dashed line. 7A and 7B are diagrams showing the state after the insulating film 118 is formed, respectively, in which the arrows indicate the state shown in FIG. 1(A) is a cross-sectional view corresponding to the dashed dotted line AB and the dashed dotted line CD.

[0149] The first oxide semiconductor film 110 shown in FIG. 7 is a film ( Here, oxygen vacancies are compensated for by the movement of oxygen from the insulating films 107 and 114. In particular, in the liquid crystal display device of one embodiment of the present invention, the first oxide semiconductor film 110 When the oxide semiconductor film is formed by sputtering, oxygen gas is used to form the insulating film 107. When oxygen is added, the insulating film 107 has an excess oxygen region. When the oxide semiconductor film 111 is formed by sputtering, oxygen gas is used to form the insulating film 116. Since oxygen is added to the insulating film 116, the insulating film 116 has an excess oxygen region. The first oxide semiconductor film 110 sandwiched between the insulating films having the insulating film region has a structure in which oxygen vacancies are suitably filled. do.

[0150] Further, the insulating film 106 is provided below the insulating film 107, and the insulating films 114 and 11 An insulating film 118 is provided above the insulating films 106 and 118. By forming the insulating films 107, 114, and 116 from a thin material such as silicon nitride, The oxygen contained therein can be confined on the first oxide semiconductor film 110 side. This allows oxygen to be transferred to the first oxide semiconductor film 110. 8 is a diagram showing the structure of the transistor when external impurities such as water, alkali metals, alkaline earth metals, etc. This also has the effect of preventing diffusion into the first oxide semiconductor film 110 included in the sta 150.

[0151] The insulating film 118 contains either hydrogen or nitrogen, or both. By forming the insulating film 118, the second oxide semiconductor film 111 in contact with the insulating film 118 By adding either or both of hydrogen and nitrogen, the carrier density increases, It can function as an oxide conductive film.

[0152] As the resistivity of the second oxide semiconductor film 111 decreases, the The second oxide semiconductor film 111 is shown with different hatching.

[0153] The resistivity of the second oxide semiconductor film 111 is at least higher than that of the first oxide semiconductor film 110. as low as possible, preferably 1×10 -3 Ωcm or more 1×10 4 less than Ωcm, more preferably , 1×10 -3 Ωcm or more 1×10 -1 It is preferable that the resistivity is less than Ωcm.

[0154] Next, the insulating film 118 is patterned so that desired regions remain, and then unnecessary regions are etched away. By etching, openings 142 are formed (see FIG. 6(B)).

[0155] The opening 142 is formed so as to expose the drain electrode 112b. As a method for forming the openings, for example, a dry etching method can be used. The method for forming 42 is not limited to this, and may be a wet etching method or a dry etching method. The opening 14 may be formed by a combination of the etching method and the wet etching method. In the case where the thickness of the drain electrode 112b is reduced by the etching process for forming the drain electrode 112b, There is a match.

[0156] The step of forming the opening 142 is omitted and the step of forming the opening 141 is omitted. By this process, openings may be formed continuously in the insulating films 114, 116, and 118. This allows the number of steps in manufacturing the liquid crystal display device of one embodiment of the present invention to be reduced. This reduces manufacturing costs.

[0157] Next, an insulating film 119 is formed on the insulating film 118, and a desired region of the insulating film 119 is left. Then, the unnecessary area is etched away to form the opening 143. A conductive film is formed on the insulating film 119 so as to cover the opening 143, and a desired region of the conductive film is The conductive film 120 is then patterned so that the conductive film 120 remains. (See FIG. 6(C)).

[0158] The opening 143 is formed without performing the steps of forming the openings 141 and 142. In this process, openings may be formed in succession in the insulating films 114, 116, 118, and 119. By employing such a process, the number of steps for manufacturing the liquid crystal display device of one embodiment of the present invention can be reduced. This makes it possible to reduce manufacturing costs.

[0159] The insulating film 119 and the conductive film 120 can be formed by selecting the materials from the above-listed materials. In this embodiment, an acrylic resin is used as the insulating film 119. The conductive film 120 is made of an Ag—Pd—Cu alloy.

[0160] In addition, the capacitor element 160 is fabricated along with the formation of the conductive film 120. The capacitor element 160 is A dielectric layer is sandwiched between a pair of electrodes, one of which is a second oxide semiconductor. The other of the pair of electrodes is a conductive film 111, and the other of the pair of electrodes is a conductive film 120. 9 functions as a dielectric layer of the capacitance element 160.

[0161] Next, an insulating film is formed on the insulating film 119 and the conductive film 120, and a pattern is formed so that a desired region remains. Then, the unnecessary area is etched to form an insulating film 130 (FIG. 8 The insulating film 130 is provided so as to cover the end portion of the conductive film 120. However, the insulating film 130 is formed between the pixel having the transistor 150 and the transistors of the adjacent pixels. The conductive film 121 has an opening for electrically connecting the transistor to the conductive film 121 .

[0162] The insulating film 130 can be formed by selecting from the materials listed above. In this embodiment, the insulating film 130 is made of acrylic resin.

[0163] Next, a conductive film to be the conductive film 121 is formed on the insulating film 119, the conductive film 120, and the insulating film 130. The desired area is then patterned, and the unwanted area is then etched away. Thus, the conductive film 121 is formed (see FIG. 8B).

[0164] The conductive film 121 can be formed by selecting from the materials listed above. In this embodiment, the conductive film 121 is made of an Ag—Pd—Cu alloy.

[0165] Through the above steps, the liquid crystal display device shown in FIGS. 1(A) and 1(B) can be manufactured. .

[0166] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0167] (Embodiment 2) In this embodiment, a liquid crystal display device according to one embodiment of the present invention is described. Modified examples of the display device will be described with reference to FIGS. 9 to 11. 1 to 8, the same reference numerals are used to denote parts having the same functions as those in the figures. The numbers are used and repeated explanations are omitted.

[0168] <Configuration Example (Modification) of Liquid Crystal Display Device> 9A is a top view of a liquid crystal display device according to one embodiment of the present invention, and FIG. 9B is a top view of a liquid crystal display device according to one embodiment of the present invention. A) corresponds to the cross-sectional view of the cut surface between the dashed dotted line EF and the dashed dotted line GH. In FIG. 9A, in order to avoid complication, some of the components of the liquid crystal display device are shown. (Gate insulating film, etc.) are omitted in the illustration.

[0169] The liquid crystal display device shown in FIGS. 9A and 9B includes a transistor including a first oxide semiconductor film 110. The transistor 150 includes a capacitor element 160 having an insulating film between a pair of electrodes. The configurations of the capacitor 150 and the capacitor element 160 are the same as those of the liquid crystal display device shown in FIGS. 1(A) and 1(B). 9A indicates the channel length direction of the transistor 150. The dashed dotted line GH indicates the channel width direction of the transistor 150.

[0170] The structure of the conductive film 120a is similar to that of the conductive film 120 shown in FIGS. The transistor 150, the capacitor 160, and the conductive film 120a shown in FIGS. Thus, one pixel of the liquid crystal display device can be formed.

[0171] The conductive film 120b can be formed at the same time as the conductive film 120a using the same material. The conductive film 120b is connected to the pixel electrode of the pixel adjacent to the pixel including the transistor 150, for example. It has the function of

[0172] In the liquid crystal display device described in this embodiment, the insulating film 130 is formed on the conductive film 120b and the conductive film 1 The conductive film 122 has a region overlapping with the insulating film 130 and the conductive film 120a. The conductive film 122 is electrically connected to the conductive film 120a.

[0173] In the liquid crystal display device shown in FIG. 9B, the insulating film 130 is formed between the conductive film 120a and the conductive film 120b. Specifically, the insulating film 130 is provided on the end of the conductive film 120a and the conductive film 120b. It is provided so as to overlap the end of the conductive film 120b.

[0174] The conductive film 120a and the conductive film 122 are insulated from each other by the insulating film 130. As a result, it is possible to eliminate a gap between the conductive film 120a and the conductive film 122 in the top view. With such a structure, the liquid crystal display device of one embodiment of the present invention can increase the aperture ratio of the pixel. In addition, by increasing the aperture ratio of the pixels, the contrast of the displayed image can be improved. Furthermore, a reflective liquid crystal display device can be provided that displays bright images.

[0175] 9A and 9B, the conductive film 120b and the conductive film 122 are formed on the insulating film 13. The ends of the two plates are arranged so as to roughly coincide with each other through the gap 0. In this example, there is no gap between the conductive film 120b and the conductive film 122. However, this is not limitative. Alternatively, there may be a gap between the conductive film 120b and the conductive film 122. As shown in A), the conductive film 120b and the conductive film 122 overlap each other via the insulating film 130. It may have a region.

[0176] As shown in FIG. 10(B), the conductive film 122 is provided under the conductive film 120a. In the liquid crystal display device shown in FIG. 10B, the conductive film 120a and the insulating film 130 are conductive. The conductive film 120a is provided on the insulating film 122, and the conductive film 120b is provided on the insulating film 130. The conductive film 120b and the conductive film 120c can be formed simultaneously using the same material. In the above, there is no gap between the conductive film 120b and the conductive film 122. However, as shown in FIG. 11A, the conductive film 120b and the conductive film 122 are formed on the insulating film 130. The second and third layers may have overlapping regions therebetween.

[0177] In addition, the thickness of the insulating film 119 is adjusted depending on the capacitance value required for the capacitor element 160 in the liquid crystal display device. The film thickness can be adjusted as appropriate. In addition, the insulating film 119 may not be provided. FIG. 11(B) shows an example of a cross-sectional view of a liquid crystal display device that does not have an insulating film 119. ), the insulating film 118 functions as a dielectric film for the capacitive element 160.

[0178] Note that the resistance of the first oxide semiconductor film 110 and the second oxide semiconductor films 111 and 111a is The resistivity can be controlled by taking into consideration the description of the first embodiment.

[0179] The materials and manufacturing method of each layer of the liquid crystal display device shown in this embodiment mode are the same as those described in Embodiment 1. The conductive films 120a and 120b can be formed using the same material and method as those of the conductive films 120a and 120b in Embodiment 1. The material and manufacturing method of the conductive film 122 can be referred to. See 121.

[0180] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0181] (Embodiment 3) In this embodiment, a liquid crystal display device according to one embodiment of the present invention is described. A modified example of the display device will be described with reference to FIG.

[0182] <Configuration example of liquid crystal display device> FIG. 12A is a top view of a liquid crystal display device of one embodiment of the present invention, and FIG. 12(A) corresponds to the cross-sectional view of the cut surface between the dashed dotted lines IJ and KL. In FIG. 12(A), in order to avoid complication, the components of the liquid crystal display device are not shown. Some elements (colored films, gate insulating films, etc.) are omitted in the illustration.

[0183] The dashed dotted line IJ in FIG. 12A indicates the channel length direction of the transistor 151. The dashed line KL indicates the channel width direction of the transistor 151. In this document, the channel length direction of the transistor is the direction from the source (source region or source electrode) The direction in which carriers move between the drain and the drain (drain region or drain electrode) The channel width direction is perpendicular to the channel length direction in a plane parallel to the substrate. means the direction of.

[0184] The liquid crystal display devices shown in FIGS. 12A and 12B include a first oxide semiconductor film 110 and a second oxide semiconductor film 111. A transistor 151 including an oxide semiconductor film 111a and a capacitor including an insulating film between a pair of electrodes In the capacitor 160, one of a pair of electrodes is a second oxide. The other of the pair of electrodes is a conductive film 120 .

[0185] The transistor 151 includes a gate electrode 104 on a substrate 102 and a second gate electrode 104 on the gate electrode 104. an insulating film 108 that functions as a gate insulating film of the first gate electrode 104; The first oxide semiconductor film 110 at the overlapping position and the source on the first oxide semiconductor film 110 The first oxide semiconductor film 110, the source electrode 112a, the drain electrode 112b, the first oxide semiconductor film 110, the source electrode 112a, the drain electrode 112b, the first oxide semiconductor film 110, the source electrode 112b, the drain ...b, the drain electrode 11 12a and the insulating film 114 acting as a second gate insulating film on the drain electrode 112b. , 116, and the second oxide semiconductor film 110 on the insulating film 116 at a position overlapping the first oxide semiconductor film 110. The transistor 15 shown in FIGS. 1 is a so-called double gate structure.

[0186] In addition, the second oxide semiconductor film 111a and the insulating film 111b are formed over the transistor 151, more specifically, Insulating films 118 and 119 are formed on the insulating film 116. The insulating film 119 functions as a protective insulating film for the transistor 151. The insulating films 114, 116, 118, and 119 also function as drain electrodes. An opening 143 is formed to reach the electrode 112b, and an insulating film 119 is formed to cover the opening 143. The conductive film 120 is formed on the transistor 151. The conductive film 120 functions as a pixel electrode of a liquid crystal display device, for example. do.

[0187] The capacitor 160 is a first electrode that functions as one of a pair of electrodes over the insulating film 116. The second oxide semiconductor film 111 and the second oxide semiconductor film 112 function as a dielectric film on the second oxide semiconductor film 111. Insulating films 118 and 119, and the second oxide semiconductor film 111 via the insulating films 118 and 119. a conductive film 120 that functions as the other electrode of the pair of electrodes at the overlapping position; That is, the conductive film 120 functions as a pixel electrode and as an electrode of a capacitor element. do.

[0188] The transistor 151, the capacitor 160, and the conductive film 120 shown in FIGS. This can form one pixel of the liquid crystal display device.

[0189] The insulating film 130 is provided on the end of the conductive film 120. A conductive film 121 is provided. The conductive film 121 is formed on a substrate including a transistor 151, for example. It functions as a pixel electrode for the pixel and the adjacent pixel.

[0190] The conductive film 120 and the conductive film 121 are insulated from each other by the insulating film 130. As a result, the gap between the conductive film 120 and the conductive film 121 can be eliminated in the top view. With such a structure, the liquid crystal display device of one embodiment of the present invention can increase the aperture ratio of a pixel. In addition, by increasing the aperture ratio of the pixels, the contrast of the displayed image can be increased. Furthermore, a reflective liquid crystal display device can be provided that displays bright images.

[0191] In addition, a colored film 170 is provided on the conductive film 120, and a colored film 171 is provided on the conductive film 121. By providing a colored film on the conductive film, the pixel electrode in one pixel is This suppresses crosstalk, which occurs when reflected light passes through the colored film of adjacent pixels, improving the viewing angle of reflective LCD devices. This configuration also reduces the field angle dependency. Since it is not necessary to provide a colored film on the substrate facing the plate 102 (hereinafter also referred to as the facing substrate), Therefore, the alignment accuracy required when bonding the substrate 102 and the opposing substrate can be reduced. Therefore, the yield in manufacturing the liquid crystal display device can be improved.

[0192] In FIG. 12B, the insulating film 130 is formed on the conductive film 120 so as to cover the end of the conductive film 120. The insulating film 130 is provided only near the end of the insulating film 120, but is not limited to this. Even if the film 130 and the conductive film 121 are overlapped so that their ends are substantially aligned with each other, 12A and 12B, the conductive film 120 and the conductive film 12 1 have an area where they overlap with each other through the insulating film 130, but the conductive film 120 and the conductive film 121 There may be no overlapping areas.

[0193] The thickness of the insulating film 119 is determined according to the capacitance value required for the capacitor element 160 in the liquid crystal display device. The thickness can be adjusted as appropriate. Alternatively, the insulating film 119 may not be provided.

[0194] 12(A) and 12(B) has a second oxide semiconductor layer on the insulating film 116. The second oxide semiconductor film 111a is formed on the second oxide semiconductor film 111b. By simultaneously depositing and etching 11, the film overlaps with the channel region of the transistor. For example, the second oxide semiconductor film 111a may be formed of a second oxide semiconductor film. The semiconductor film 111 is formed at the same time as the semiconductor film 111 and etched at the same time. Therefore, the increase in process steps can be suppressed. One aspect of the embodiment is not limited thereto. The oxide semiconductor film 111 may be formed in a different process from that of the oxide semiconductor film 111.

[0195] The second oxide semiconductor film 111a is a first oxide semiconductor film that serves as a channel region of the transistor 151. Therefore, the second oxide semiconductor film 11 1a functions as the second gate electrode of the transistor 151. The second oxide semiconductor film 111a may be connected to the gate electrode 104. Alternatively, The second oxide semiconductor film 111a is not connected to the gate electrode 104. A signal or a potential different from that of the transistor may be supplied. The current driving capability of the transistor 151 can be improved.

[0196] Note that the first oxide semiconductor film 110 functions as a channel region of the transistor 151. The second oxide semiconductor film 111 is used as one of a pair of electrodes of the capacitor 160. Therefore, the second oxide semiconductor film 11 functions as a gate insulating film rather than the first oxide semiconductor film 110. The first oxide semiconductor film 110 and the second oxide semiconductor film 111 have low resistivity. It is preferable that the first oxide semiconductor film 110 and the second oxide semiconductor film 111 contain the same metal element. By configuring the film 111 to have the same metal element, it is possible to It is possible to share the same equipment (processing equipment, etc.), which reduces manufacturing costs. .

[0197] Note that the insulating film 118 provided over the transistor 151 and used for the capacitor 160 An insulating film containing at least hydrogen is used as the insulating film for the transistor 151. The insulating film 107 and the insulating films 114 and 116 provided on the transistor 151 include: An insulating film containing at least oxygen is used. 60, and an insulating film used over the transistor 151 and the capacitor 160. By using the insulating film having the above structure, the first oxide semiconductor of the transistor 151 The resistivity of the conductive film 110 and the second oxide semiconductor film 111 of the capacitor 160 is controlled. The first oxide semiconductor film 110 and the second oxide semiconductor films 111 and 11 The resistivity of 1a can be controlled by taking into consideration the description of the first embodiment. .

[0198] In the transistor 151, the first oxide semiconductor film 110 serves as a channel region. Since the second oxide semiconductor film 111 is used as the second oxide semiconductor film 112, the second oxide semiconductor film 111 has a higher resistivity than the second oxide semiconductor film 111. The oxide semiconductor films 111 and 111a function as electrodes. It has a lower resistivity compared to the film 110 .

[0199] The materials and manufacturing method of each layer of the liquid crystal display device shown in this embodiment mode are the same as those described in Embodiment 1. Materials that can be used for the colored films 170 and 171 include metal materials, resin materials, and the like. Examples of the material include an oil material, a resin material containing a pigment or a dye, and the like.

[0200] As described above, the structures, methods, etc. described in this embodiment may be different from the structures, methods, etc. described in other embodiments. They can be used in appropriate combinations.

[0201] (Fourth embodiment) In this embodiment, a liquid crystal display device 80 according to one embodiment of the present invention will be described with reference to FIGS. 5 will be used to explain.

[0202] The liquid crystal display device 80 shown in FIG. 13A includes a pixel section 71, a scanning line driving circuit 74, and a signal The scanning line driving circuit 76 and the scanning line driving circuit 74 are arranged parallel or approximately parallel to each other. m scanning lines 77 whose potentials are controlled by the scanning lines 77, which are arranged parallel or approximately parallel to each other and and n signal lines 79 whose potentials are controlled by a line driving circuit 76. m and n are Furthermore, the pixel section 71 is made up of a plurality of pixels 7 arranged in a matrix. 0. Capacitor wirings are arranged parallel or approximately parallel to each other along the scanning lines 77. The scanning line driving circuit 74 and the signal line driving circuit 76 are collectively referred to as a driving circuit section. This is sometimes the case.

[0203] Each scanning line 77 is connected to any one of the pixels 70 arranged in m rows and n columns in the pixel section 71. The signal lines 79 are electrically connected to the n pixels 70 arranged in one row. Among the pixels 70 arranged in m rows and n columns, m pixels 70 arranged in any one of the columns are electrically connected. Furthermore, each capacitance wiring 75 is electrically connected to any one of the pixels 70 arranged in m rows and n columns. It is electrically connected to n pixels 70 arranged in any one row.

[0204] FIG. 13B shows a pixel 70 that can be used in the liquid crystal display device 80 shown in FIG. 13A. 1 shows an example of a circuit configuration.

[0205] The pixel 70 shown in FIG. 13B includes a liquid crystal element 51, a transistor 50, and a capacitor 55. and,

[0206] One of the pair of electrodes of the liquid crystal element 51 is connected to the transistor 50, and the potential is The other of the pair of electrodes of the liquid crystal element 51 is connected to a common line (not shown). The liquid crystal is connected to a common potential (common potential) that is common to all pixels. The orientation of the liquid crystal in the element 51 is controlled by data written to the transistor 50. will be done.

[0207] The liquid crystal element 51 controls the transmission or non-transmission of light by the optical modulation action of the liquid crystal. The optical modulation effect of the liquid crystal is achieved by the electric field applied to the liquid crystal (horizontal electric field, vertical electric field). The liquid crystal element 51 is controlled by a diagonal electric field or a forward electric field. Liquid crystals include thermotropic liquid crystals, low molecular weight liquid crystals, polymer liquid crystals, polymer dispersed liquid crystals, and strong Dielectric liquid crystal, antiferroelectric liquid crystal, etc. can be used. These liquid crystal materials can be used depending on the conditions. , cholesteric phase, smectic phase, cubic phase, chiral nematic phase, isotropic phase etc.

[0208] In addition, when the in-plane switching method is adopted, a liquid crystal that exhibits a blue phase without using an alignment film may be used. The blue phase is one of the liquid crystal phases, and when the temperature of cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the black phase to the isotropic phase. Therefore, in order to improve the temperature range, a liquid crystal composition containing a chiral agent of several weight percent or more is used. The liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent is used in a liquid crystal layer. It has a short response time and is optically isotropic. It also contains a liquid crystal that exhibits a blue phase and a chiral agent. The liquid crystal composition does not require alignment treatment and has little viewing angle dependency. Since the rubbing process is unnecessary, electrostatic breakdown caused by the rubbing process can be prevented. Therefore, defects and damage to the liquid crystal display device during the manufacturing process can be reduced. do.

[0209] The liquid crystal display device 80 having the liquid crystal element 51 can be driven by a TN (Twisted Nematic) method. Nematic (IPS) mode, In-Plane-Switching (IPS) mode, F FS (Fringe Field Switching) mode, ASM (Axiall y Symmetric aligned Micro-cell) mode, OCB(O Optical Compensated Birefringence (FLC) mode, FLC (Ferroelectric Liquid Crystal) mode, AFLC(A Antiferroelectric Liquid Crystal mode It is possible.

[0210] As a method for driving the liquid crystal display device 80 having the liquid crystal element 51, MVA (Multi-Voltage Alignment) -Domain Vertical Alignment mode, PVA (Pattern Vertical alignment modes such as rned Vertical Alignment (AVA) mode and ASV mode A forward mode can be used.

[0211] In the configuration of the pixel 70 shown in FIG. 13B, the source electrode and the drain electrode of the transistor 50 One of the electrodes is electrically connected to the signal line 79, and the other is one of the pair of electrodes of the liquid crystal element 51. The gate electrode of the transistor 50 is electrically connected to the scanning line 77. The transistor 50 has the function of controlling the writing of data of the data signal. Has.

[0212] In the configuration of the pixel 70 shown in FIG. 13B, one of the pair of electrodes of the capacitor element 55 is The pair of capacitor elements 55 are connected to the other of the source electrode and the drain electrode of the transistor 50. The other electrode is electrically connected to a capacitance wiring 75. The potential value of the capacitance wiring 75 is The capacitance element 55 is a storage element for storing written data. It functions as a storage capacitor.

[0213] <Configuration example of liquid crystal display device> Next, a specific configuration of the liquid crystal display device 80 will be described. A top view of a plurality of pixels 70R, 70G, and 70B having the same structure is shown in FIG. Only the configuration of the element substrate included in the liquid crystal display device 80 is shown. A cross-sectional view of the liquid crystal display device 80 taken along the dashed line P1-P2 is shown in FIG. R, 70G, and 70B are pixels that display red, green, and blue, respectively. The device 80 emits red, green, and blue light at positions overlapping the pixels 70R, 70G, and 70B, respectively. This can be achieved by providing selectively transparent colored films 340R, 340G, and 340B.

[0214] The liquid crystal display device 80 includes a pixel 70R, a pixel 70G, and a pixel 70B. The pixel 70G has a pixel electrode 320R and a transistor 50R. pixel 70B has pixel electrode 320B and transistor 50B; The transistor 50R is electrically connected to the signal line 79R and the scanning line 77. The transistor 50G is electrically connected to the signal line 79G and the scanning line 77. 0B is electrically connected to the signal line 79B and the scanning line 77.

[0215] In addition, the pixel 70R has a pixel electrode 320R and an oxide semiconductor film 311R as a pair of electrodes. The pixel 70G has a pixel electrode 320G and an oxide semiconductor film 311G. The pixel 70B has a capacitance element as a pair of electrodes. The oxide semiconductor films 311R, 311G, and 311B are used as a pair of electrodes. 11B is electrically connected to the capacitance wiring 75.

[0216] The liquid crystal display device 80 has at least three transistors (50R, 50G and 50B), and an insulating film 318 covering the transistor and a The pixel electrodes 320R, 320G, and 320B are insulated. It is provided on the membrane 319 .

[0217] Furthermore, through the openings of the insulating films 314, 316, 318, and 319, the pixel electrode 320R and the The source electrode or the drain electrode of the transistor 50R is electrically connected to the pixel electrode 32 The source electrode or the drain electrode of the transistor 50G is electrically connected to the pixel voltage. The electrode 320B is electrically connected to the source electrode or the drain electrode of the transistor 50B. An alignment film 335 is provided on the pixel electrodes 320R, 320G, and 320B.

[0218] The liquid crystal display device 80 has colored films 340R, 340G, and 340B on the side of the substrate 303. The insulating film 344, the common electrode 345, and the alignment film 336 are arranged so as to overlap the colored films of each color. For example, the liquid crystal element 51B in the pixel 70B has a pixel electrode 320B and a common electrode 34B. 5, and a liquid crystal layer 341 sandwiched between the pixel electrode 320B and the common electrode 345. The insulating film 344 may also function as a planarizing film. It may not be provided.

[0219] One end of the pixel electrode 320B is connected to the pixel electrode 320B with the insulating film 330a interposed therebetween. The other end of the pixel electrode 320B is disposed on the insulating film 330b. The pixel electrode 320R is provided so as to overlap the pixel electrode 320R.

[0220] In FIG. 15, the insulating films 330a and 330b are formed on the pixel electrodes 320R and 320G, respectively. The end portion is covered by the cover, but is not limited to this. In this way, the insulating film 330B covers the ends of the pixel electrodes 320R and 320G, and the insulating film 330 The liquid crystal display panel 300 may be provided so that the edge of the pixel electrode 320B is substantially aligned with the edge of the pixel electrode 320B. In the display device 80, an opening is provided in the insulating film 330B, and the pixel electrode 3 20B and the source electrode or the drain electrode of the transistor 50B are electrically connected.

[0221] In addition, in FIG. 16, an insulating film 330B is provided under the pixel electrode 320B, and the pixel electrode 320R, Although the configuration is such that it is not provided below 320G, this is not limited to this. In the pixel 70R adjacent to the pixel 70G, an insulating film 330R is provided under the pixel electrode 320R. In the pixel 70G adjacent to the pixel 70R, an insulating film 330G is formed under the pixel electrode 320G. With this configuration, the pixels 70R, 70G, and 70B may each be In a liquid crystal display device having a plurality of pixels, the aperture ratios of the pixels 70R, 70G, and 70B are uniformly increased. It is possible.

[0222] Incidentally, when there is a gap between two adjacent pixel electrodes, The liquid crystal display device shown in FIG. 20G, pixel electrode 320G and pixel electrode 320B, and pixel electrode 320B and pixel electrode 320 A gap is formed between the insulating film 318 and the insulating film 318, and a structure 333 is provided at a position overlapping the gap. The structure 333 can be made of a material that blocks visible light. It functions as a rack matrix. When wiring or the like is present in the display, the wiring is prevented from reflecting external light, and the display is Trust can be improved.

[0223] As shown in FIG. 19, a plurality of pixel electrodes of a liquid crystal display device are formed using a plurality of materials. In FIG. 19, the pixel electrodes 320R and 320G may be made of the same material. The pixel electrode 320B can be formed of a material different from that of the pixel electrodes 320R and 320G. For example, APC is used for the pixel electrodes 320R and 320G, and the pixel electrode 320B Aluminum can be used for this purpose. Aluminum has a wavelength range of blue light (e.g., 400 Since the reflectance in the wavelength range (nm to 450nm) is higher than that of APC, The pixel electrode 320R can be suitably used as the pixel electrode of the pixel 70B. The thickness of the liquid crystal layer 341 of the liquid crystal element is changed by changing the film thickness of the pixel electrode 320G and the film thickness of the pixel electrode 320B. The liquid crystal layer 341 can be adjusted for each pixel according to the wavelength of light passing through the liquid crystal layer 341. By changing the thickness of 41, it is possible to efficiently extract external light in a reflective LCD device. In FIG. 19, the insulating film 330 is provided between adjacent pixels of different colors. The ends of the pixel electrodes (320G, 320R) and the insulating film 330 located above are generally aligned. The insulating film 330 is entirely formed on the insulating film 319. The insulating film 3 may be provided on the pixel electrode so as to cover the edge of the pixel electrode. 30 is provided so as to cover the end of the pixel electrode 320B. The ends of the pixel electrodes (320G, 320R) located on the insulating film 330 are aligned with the ends of the insulating film 330. It may be located inside the part.

[0224] In the liquid crystal display device of one embodiment of the present invention, an insulating film is interposed between two adjacent pixel electrodes. In this way, it is possible to eliminate the gap between two adjacent pixel electrodes in the top view. By having such a structure, the aperture ratio of the pixel can be increased. The aperture ratio of the liquid crystal display device is 75% or more and less than 100%, preferably 90% or more and less than 100%. More preferably, it can be 98% or more and less than 100%.

[0225] In addition, in the top view, the boundary between two adjacent pixel electrodes with the insulating film 330 interposed therebetween and the It is preferable that the boundaries between the two pixel electrodes and the colored films that overlap with them do not coincide with each other. For example, as shown in FIG. 22, the pixel electrode 320B is overlapped with the colored film 340R near its end. It is preferable to provide it so that

[0226] The pixel electrode 320B and the adjacent pixel electrode 320R are on the insulating film 330. The distance between the pixel electrode 320R and the common electrode 345 on the substrate 30 is The distance between the insulating film 330 and the pixel electrode 345 is smaller than the distance between the insulating film 330 and the pixel electrode 345. From the above, the pixel electrode 320B and the pixel electrode 320R are located at the boundary between them. In the vicinity of the field, the pixel voltage is higher than the electric field applied between the pixel electrode 320B and the common electrode 345. The electric field applied between the pixel electrode 320R and the common electrode 345 is larger. The electric field formed by 0R also extends to the position where it overlaps with the vicinity of the edge of the pixel electrode 320B. Therefore, by providing the pixel electrode 320B so that the vicinity of its end overlaps with the colored film 340R, This effectively prevents light leakage from pixel 70B during display of pixel 70R. For the same reason, the pixel electrode 320B is provided so that the vicinity of its end overlaps with the colored film 340G. By doing so, it is possible to effectively suppress light leakage from the pixel 70B when displaying the pixel 70G. can.

[0227] For example, in FIG. 22, the width W R , the width W of the pixel electrode 320G G That's it 18 μm, and the width W of the pixel electrode 320B B1 is 21.5μm. Also, APC The thickness of the pixel electrodes 320R and 320G formed using aluminum is 100 nm. Assume that the thickness of the pixel electrode 320B formed using aluminum is 300 nm. When the distance d1 between the surface of 20R and the surface of the common electrode 345 is 2.2 μm, the pixel electrode The end of the colored film 320B is positioned 0.5 μm outside the end of the colored film 340B. Width of 340B B2 By setting the thickness to 20.5 μm, light leakage from the liquid crystal display device 80 is suppressed, This in turn improves the color purity of the display. The end of R and the end of the colored film 340B and the end of the colored film 340G are aligned. do.

[0228] Also, as shown in FIG. 23, a colored film may be provided on the pixel electrode. The color films 340R, 340G, and 340B are respectively disposed on the pixel electrodes 320R, 320G, and 320B. In this case, the alignment film 335 may be provided in contact with the colored films 340R, 340G, and 340B. The alignment film 336 is provided on the common electrode 345. By doing so, the reflected light from the pixel electrode of one pixel (for example, pixel 70B) is reflected by the adjacent pixel ( For example, crosstalk passing through the colored film of pixel 70G is suppressed, and the viewing angle of the reflective liquid crystal display device is improved. The field angle dependency can be suppressed. In addition, it is no longer necessary to provide a colored film on the substrate 303 side. Therefore, the alignment accuracy required when bonding the substrate 302 and the substrate 303 can be reduced. Therefore, the yield in manufacturing the liquid crystal display device can be improved.

[0229] In addition to the configuration of FIG. 23, an overcoat film is provided on the colored film, and a conductive film is provided on the insulating film. The liquid crystal display device shown in FIG. On the top surface, there is an overcoat film 337 and conductive films 325R, 325G, and 325B. The film 325R is exposed to the image through an opening provided in the overcoat film 337 and the colored film 340R. The conductive film 325G is electrically connected to the base electrode 320R. The colored film 340G is electrically connected to the pixel electrode 320G through an opening provided in the colored film 340G. The film 325B is exposed to the image through an opening provided in the overcoat film 337 and the colored film 340B. It is electrically connected to the base electrode 320B.

[0230] The conductive films 325R, 325G, and 325B are light-transmitting conductive films, and are, for example, common The same material as that of the electrode 345 can be used. For example, the liquid crystal element 51B in the pixel 70B includes a conductive film 325B, a common electrode 345, It is composed of a liquid crystal layer 341 sandwiched between a conductive film 325B and a common electrode 345. The conductive films 325R, 325G, and 325B function as pixel electrodes. 20R, 320G, and 320B function as reflective films.

[0231] The transistors 50R, 50G, and 50B are the same as the transistor 150 described in the first embodiment. The transistor 50R can be fabricated using the same materials and forming methods as those of the transistor 50A. The transistor 270 described in the sixth embodiment may be used as 50G and 50B.

[0232] As shown in FIG. 25, the transistors 50R, 50G, and 50B have a second gate voltage The second gate electrode is preferably connected to the semiconductor layer of the transistor and the pixel electrode. The second gate electrode can be provided between the electrodes at a position overlapping the semiconductor layer. For example, The oxide semiconductor film 311R can be formed simultaneously using the same material as the oxide semiconductor film 311R. 15, the liquid crystal display device 80 has the transistors 50R, 50G, and 50B in the second The difference is that the oxide semiconductor film 311a functions as a gate electrode. 0R, 50G, and 50B have the second gate electrode, so that the distance between the semiconductor layer and the pixel electrode When the pixel electrode potential is close to the threshold voltage, the influence of the pixel electrode potential change on the transistor characteristics is suppressed. By providing pixel electrodes at positions overlapping with the transistors, the liquid crystal display device 80 The aperture ratio can be increased.

[0233] The capacitive elements of the pixels 70R, 70G, and 70B are the same as those described in the first embodiment. The capacitor element can be manufactured using the same materials and forming methods as those of the capacitor element 160. The insulating films 318 and 319 function as dielectric films.

[0234] The pixel electrodes 320R, 320G, and 320B are formed by the conductive film 12 described in the first embodiment. 0 can be fabricated using the same materials and forming methods. For example, a material that is transparent to visible light may be used. Uses a material containing one of the following elements: indium (In), zinc (Zn), and tin (Sn). The common electrode 345 may be made of, for example, indium containing tungsten oxide. oxide, indium zinc oxide with tungsten oxide, indium oxide with titanium oxide oxides, indium tin oxide containing titanium oxide, indium tin oxide (ITO) Indium Tin Oxide, Indium Zinc Oxide, Indium Tin with Silicon Oxide Addition A conductive material having light transmitting properties, such as an oxide, can be used. For example, the insulating film 10 can be formed by sputtering.

[0235] The insulating film 344 is formed by depositing silicon oxide by plasma CVD, sputtering, or the like. film, silicon oxynitride film, silicon nitride oxide film, silicon nitride film, aluminum oxide film, Hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, titanium oxide film tantalum film, magnesium oxide film, lanthanum oxide film, cerium oxide film and neodymium oxide film An insulating film containing one or more of the following can be used.

[0236] 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.

[0237] (Embodiment 5) In this embodiment, a transistor and a capacitor in a liquid crystal display device according to one embodiment of the present invention are applied. An example of a possible oxide semiconductor will be described.

[0238] The structure of an oxide semiconductor will be described below.

[0239] In this specification, "parallel" means that two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, it includes the case where the angle is between -5° and 5°. "Parallel" refers to a state in which two lines are arranged at an angle of between -30° and 30°. Also, "perpendicular" means that two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, it also includes cases where the angle is between 85° and 95°. This refers to a state in which two straight lines are arranged at an angle of 60° or more and 120° or less.

[0240] In this specification, when the crystal is a trigonal or rhombohedral crystal, it is represented as a hexagonal crystal system. vinegar.

[0241] Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single-crystal oxide semiconductor, CAAC-OS (C Axis Aligned Crystalline Oxide Semiconductor, polycrystalline oxide Semiconductor, nc-OS (nanocrystalline oxide semiconductor) uctor), pseudo-amorphous oxide semiconductor (a-like OS: amorphous l Examples include amorphous oxide semiconductors, amorphous oxide semiconductors, and amorphous oxide semiconductors.

[0242] From another point of view, oxide semiconductors are classified into amorphous oxide semiconductors and other crystalline oxides. Crystalline oxide semiconductors are divided into single-crystal oxide semiconductors, CAAC- Examples include OS, polycrystalline oxide semiconductor, and nc-OS.

[0243] The definition of an amorphous structure is generally that it is not fixed in a metastable state and is isotropic. It is known that the bond angle is flexible and the bond is short-range. This can also be described as a structure that has a high degree of order but no long-range order.

[0244] On the other hand, in the case of an essentially stable oxide semiconductor, it is possible to obtain a completely amorphous structure. It cannot be called an oxide semiconductor (isotropic amorphous). The oxide semiconductor is then oxidized to form a completely amorphous structure. However, a-like OS is a semiconductor that can be used in a microscopic area. Although it has a periodic structure, it has voids and is an unstable structure. It can be said that the physical properties are similar to those of an amorphous oxide semiconductor.

[0245] <caac-os> First, let me explain about CAAC-OS.

[0246] CAAC-OS is an oxide having multiple crystal parts (also called pellets) aligned along the c-axis. It is a type of semiconductor.

[0247] Transmission Electron Microscope (TEM) A combined analysis image (high resolution) of the bright-field image and diffraction pattern of CAAC-OS was obtained by using a microscope. When observing a high-resolution TEM image, multiple pellets can be confirmed. On the other hand, high-resolution TEM images reveal the boundaries between pellets, i.e., grain boundaries. Therefore, the CAAC-OS is not clearly characterized by the grain boundaries. It can be said that the resulting decrease in electron mobility is unlikely to occur.

[0248] Below, we will explain the CAAC-OS observed by TEM. 1 shows a high-resolution TEM image of a cross section of CAAC-OS observed from a direction approximately parallel to the sample surface. For high-resolution TEM imaging, spherical aberration correction is required. The spherical aberration correction function was used to obtain high-resolution TEM images. , specifically referred to as a Cs-corrected high-resolution TEM image. Cs-corrected high-resolution TEM images can be obtained, for example, This is performed using an atomic resolution analytical electron microscope such as the JEM-ARM200F manufactured by JEOL Ltd. It is possible.

[0249] An enlarged Cs-corrected high-resolution TEM image of region (1) in Figure 26(A) is shown in Figure 26(B). From Figure 26(B), it can be seen that the metal atoms are arranged in layers in the pellet. The arrangement of each metal atom layer is determined by the surface on which the CAAC-OS film is to be formed (also referred to as the surface on which the film is to be formed). Or it reflects the unevenness of the top surface and is parallel to the surface on which the CAAC-OS is formed or the top surface.

[0250] As shown in Figure 26(B), CAAC-OS has a characteristic atomic arrangement. ) shows the characteristic atomic arrangement with auxiliary lines. ) the size of each pellet can be 1 nm or more, or 3 nm or more. It can be seen that the size of the gap caused by the tilt between the sintered body and the pellet is about 0.8 nm. Therefore, the pellets can also be called nanocrystals (nc). CAAC-OS is also used for CANC (C-Axis Aligned Nanoclip). The semiconductor may also be referred to as an oxide semiconductor having metals.

[0251] Here, based on the Cs-corrected high-resolution TEM image, the pellets of CAAC-OS on the substrate 5120 were The layout of the 5100 is shown diagrammatically as a stack of bricks or blocks. (See FIG. 26(D)). Between the pellets observed in FIG. 26(C), The portion where the tilt occurs corresponds to the area 5161 shown in FIG.

[0252] FIG. 27(A) shows the C of the plane of the CAAC-OS observed from a direction approximately perpendicular to the sample surface. The s-corrected high-resolution TEM images are shown. Regions (1), (2), and (3) in Figure 27(A). ) are enlarged Cs-corrected high-resolution TEM images shown in Figure 27(B), Figure 27(C), and Figure 27(D), respectively. As shown in Figure 27(D), Figure 27(B), Figure 27(C) and Figure 27(D) show that the pellet It can be seen that the metal atoms are arranged in a triangular, quadrangular or hexagonal shape. However, no regularity is observed in the arrangement of metal atoms among different pellets.

[0253] Next, C analyzed by X-ray diffraction (XRD) For example, CAAC-O with InGaZnO4 crystals When S is subjected to structural analysis using the out-of-plane method, the results are as shown in Figure 28(A). As shown in the figure, a peak may appear at a diffraction angle (2θ) of around 31°. Since this is attributed to the (009) plane of the ZnO4 crystal, it is believed that the CAAC-OS crystal is c-axis oriented. It can be seen that the c-axis is oriented in a direction substantially perpendicular to the surface on which the film is formed or the upper surface.

[0254] In addition, in the structural analysis of CAAC-OS using the out-of-plane method, 2θ is 31 In addition to the peak around 2θ of 36°, a peak may also appear around 2θ of 36°. The peaks in the vicinity indicate that some of the CAAC-OS crystals do not have a c-axis orientation. The more preferable CAAC-OS is a structure produced by the out-of-plane method. The analysis shows a peak at 2θ around 31°, but no peak at 2θ around 36°.

[0255] On the other hand, in-pla, X-rays are incident on the CAAC-OS from a direction almost perpendicular to the c-axis. When structural analysis is performed using the NE method, a peak appears at 2θ around 56°. This peak is due to I It is attributed to the (110) plane of the nGaZnO4 crystal. In the case of CAAC-OS, 2θ is set to 5 The sample is fixed at approximately 6° and analyzed while rotating around the normal vector of the sample surface (φ axis). Even if a (φ scan) is performed, no clear peak appears as shown in Figure 28(B). On the other hand, in the case of a single crystal oxide semiconductor such as InGaZnO4, 2θ is fixed at around 56° and φ When scanned, it is assigned to a crystal plane equivalent to the (110) plane as shown in Figure 28(C). Six peaks are observed. Therefore, from the structural analysis using XRD, CAAC-OS It can be seen that the orientation of the a-axis and b-axis is irregular.

[0256] Next, we will explain the CAAC-OS analyzed by electron diffraction. For CAAC-OS with ZnO4 crystals, the probe diameter is 300 nm parallel to the sample surface. When an electron beam is incident on the sample, a diffraction pattern (selected area transmission electron diffraction) as shown in FIG. This diffraction pattern may appear due to the presence of InGaZnO4 This includes spots due to the (009) plane of the crystal. The pellets contained in the CAAC-OS have a c-axis orientation, and the c-axis faces the surface to be formed or the upper surface. On the other hand, when the probe was applied to the same sample perpendicular to the sample surface, The diffraction pattern when an electron beam with a diameter of 300 nm was incident is shown in Figure 29(B). 9(B) shows a ring-shaped diffraction pattern. It can be seen that the a-axis and b-axis of the pellets contained in CAAC-OS do not have any orientation. The first ring in FIG. 29(B) is the (010) plane of the InGaZnO4 crystal. This is thought to be due to the (100) plane and the like. This is thought to be due to the (110) surface.

[0257] As described above, CAAC-OS is an oxide semiconductor with high crystallinity. Crystallinity can be reduced by the incorporation of impurities or the generation of defects, so the opposite view can be taken. Therefore, CAAC-OS can be considered an oxide semiconductor with few impurities and defects (such as oxygen vacancies).

[0258] The impurities are elements other than the main components of the oxide semiconductor, such as hydrogen, carbon, silicon, and transition metals. For example, metal elements such as silicon are more oxidative than metal elements that constitute oxide semiconductors. Elements with strong bonding strength with the oxide semiconductor remove oxygen from the oxide semiconductor, which changes the atomic arrangement of the oxide semiconductor. In addition, heavy metals such as iron and nickel, argon, Carbon dioxide and other molecules have a large atomic radius (or molecular radius), so the atomic arrangement of oxide semiconductors This disrupts the structure and reduces the crystallinity.

[0259] When an oxide semiconductor has impurities or defects, its characteristics may change due to light, heat, etc. For example, impurities contained in oxide semiconductors can act as carrier traps or In addition, oxygen vacancies in oxide semiconductors can act as carrier traps. In some cases, the SiO 2 can become a carrier generation source by capturing hydrogen.

[0260] CAAC-OS, which has few impurities and oxygen vacancies, is an oxide semiconductor with low carrier density. There is. Specifically, 8×10 11 pieces / cm 3 Less than 1 x 10 11 pieces / cm 3 Not yet less than 1×10 10 pieces / cm 3 Less than 1 x 10 -9 pieces / cm 3 End Such an oxide semiconductor can be obtained by CAAC-OS is an oxide semiconductor with an impurity concentration of 1000 uV or less. In other words, it can be said that the oxide semiconductor has stable characteristics.

[0261] <nc-os> Next, we will explain nc-OS.

[0262] In the high-resolution TEM image, nc-OS has two distinct regions: one where crystals can be confirmed and the other where clear crystals can be confirmed. The crystalline part contained in nc-OS is The size is often between 1 nm and 10 nm, or between 1 nm and 3 nm. An oxide semiconductor having a crystal size of 10 nm or more and 100 nm or less is called a microcrystalline oxide. For example, in high-resolution TEM images, nc-OS shows grain boundaries. In some cases, the nanocrystals are not clearly visible. Therefore, in the following, the crystalline part of nc-OS is referred to as the pellet. There is a chance to call.

[0263] nc-OS is a material that can be used in microscopic areas (e.g., areas between 1 nm and 10 nm, especially areas between 1 nm and 10 nm). The atomic arrangement is periodic in the region of 3 nm or less. There is no regularity in the crystal orientation between the layers. Therefore, no orientation is observed throughout the film. Therefore, depending on the analytical method, nc-OS may be classified as a-like OS or amorphous oxide semiconductor. For example, in contrast to nc-OS, there are cases where it is difficult to distinguish the particles from the pellets. When X-rays are used, the peaks that indicate the crystal planes are In addition, for nc-OS, a probe diameter larger than the pellet (e.g., 50 When electron diffraction is performed using an electron beam of 1000 nm or more, a halo-like diffraction pattern is produced. On the other hand, for nc-OS, pellets with sizes close to or smaller than the pellets were observed. When nanobeam electron diffraction is performed using an electron beam with a lobe diameter, spots are observed. When nanobeam electron diffraction is performed on nc-OS, high brightness regions are observed in a circular (ring-like) pattern. In addition, multiple spots may be observed within a ring-shaped area. This may be the case.

[0264] In this way, the crystal orientation between the pellets (nanocrystals) is not regular, so nc -OS with RANC (Random Aligned nanocrystals) oxide semiconductors, or NANCs (Non-Aligned Nanocrystals) The semiconductor may also be referred to as an oxide semiconductor having a structure (s).

[0265] The nc-OS is an oxide semiconductor with higher order than an amorphous oxide semiconductor. The nc-OS has a lower density of defect states than the a-like OS and amorphous oxide semiconductors. However, in nc-OS, there is no regularity in the crystal orientation between different pellets. Therefore, the nc-OS has a higher density of defect states than the CAAC-OS.

[0266] <a-like OS> The a-like OS is an oxide semiconductor with a structure between the nc-OS and amorphous oxide semiconductor. It is a semiconductor.

[0267] In a-like OS, pores may be observed in high-resolution TEM images. In the high-resolution TEM image, there are areas where crystalline parts can be clearly seen, and areas where crystalline parts can be seen. and areas where it is not possible to

[0268] Because of the porosity, the a-like OS has an unstable structure. e OS has an unstable structure compared with CAAC-OS and nc-OS. This shows the structural changes caused by electron irradiation.

[0269] The samples to be irradiated with electrons were a-like OS (referred to as sample A), nc-OS (hereinafter referred to as Sample B) and CAAC-OS (hereinafter referred to as Sample C) are prepared. Both samples are In-Ga-Zn oxides.

[0270] First, high-resolution cross-sectional TEM images of each sample are acquired. It can be seen that all the materials have crystalline parts.

[0271] The determination of which part is to be regarded as one crystal part can be made as follows. For example, The unit cell of the InGaZnO4 crystal has three In-O layers and one Ga-Zn-O layer. It is known that the structure has a total of nine layers, six of which are stacked in layers in the c-axis direction. The spacing between these adjacent layers is approximately the same as the lattice spacing (also called the d value) of the (009) plane. The value is calculated to be 0.29 nm from crystal structure analysis. The areas where the spacing is 0.28 nm or more and 0.30 nm or less are considered to be InGaZnO4 crystal parts. The lattice fringes correspond to the ab plane of the InGaZnO4 crystal.

[0272] Figure 30 shows an example of investigating the average size of the crystal parts (22 to 45 locations) of each sample. However, the length of the lattice fringes mentioned above is the size of the crystal part. It can be seen that the crystalline part of ke OS grows in size according to the cumulative amount of electron irradiation. Specifically, as shown in Figure 30 (1), the initial TEM observation showed a size of about 1.2 nm. The crystal part (also called the initial nucleus) was 4.2 × 10 8 e - / n m 2 On the other hand, in the nc-O For S and CAAC-OS, the cumulative electron irradiation dose from the start of electron irradiation was 4.2 × 10 8 e - / nm 2 It can be seen that there is no change in the size of the crystal part within the range of As shown in (2) and (3) in Figure 30, regardless of the cumulative electron dose, the nc-OS and The sizes of the crystal parts of the CAAC-OS and CAAC-OS are approximately 1.4 nm and 2.1 nm, respectively. It can be seen that...

[0273] In this way, the growth of crystalline parts can be observed in a-like OS due to electron irradiation. On the other hand, in nc-OS and CAAC-OS, the growth of the crystals by electron irradiation is almost nonexistent. In other words, a-like OS is not as good as nc-OS and CAAC- It is clear that it has an unstable structure compared to the OS.

[0274] In addition, due to its porosity, a-like OS is more flexible than nc-OS and CAAC-OS. Specifically, the density of a-like OS is lower than that of a single crystal of the same composition. The density of the nc-OS is 78.6% or more and less than 92.3% of that of the normal crystal. The density of C-OS is 92.3% or more but less than 100% of the density of a single crystal of the same composition. It is difficult to form a film of an oxide semiconductor having a crystal density of less than 78%.

[0275] For example, in an oxide semiconductor having an atomic ratio of In:Ga:Zn=1:1:1, The density of a single crystal InGaZnO4 having a rhombohedral crystal structure is 6.357 g / cm 3 becomes. Thus in an oxide semiconductor satisfying, for example, In:Ga:Zn = 1:1:1 [atomic ratio], the density of a-like OS is 5.0 g / cm 3 or more and less than 5.9 g / cm 3 becomes. Also for example, in an oxide semiconductor satisfying In:Ga:Zn = 1:1:1 [atomic ratio], the density of nc-OS and the density of CAAC-OS are 5.9 g / cm 3 or more and less than 6.3 g / cm 3 becomes.

[0276] Note that there may be cases where single crystals of the same composition do not exist. In that case, by combining single crystals with different compositions in any ratio, the density corresponding to a single crystal in the desired composition can be estimated . The density corresponding to a single crystal of the desired composition may be estimated using a weighted average with respect to the ratio of combining single crystals with different compositions. However, it is preferable to estimate the density by combining as few types of single crystals as possible . As described above, oxide semiconductors have various structures and each has various characteristics .

[0277] Note that the oxide semiconductor may be, for example, a laminated film having two or more of an amorphous oxide semiconductor, a-like OS, nc-OS , and CAAC-OS .

[0278] <Fabrication method of CAAC-OS> Hereinafter, an example of a fabrication method of CAAC-OS will be described. FIG. 3 is a schematic diagram of the inside of a film formation chamber . CAAC-OS can be formed by a sputtering method

[0279] As shown in FIG. 31, the substrate 5220 and the target 5230 are arranged facing each other. There is a plasma 5240 between the substrate 5220 and the target 5230. A heating mechanism 5260 is provided below the substrate 5220. Although not shown, the target 5230 is bonded to the backing plate. A number of magnets are placed facing the magnet 5230. The sputtering method that uses magnetron sputtering to increase the deposition rate is called magnetron sputtering. can be.

[0280] The distance d between the substrate 5220 and the target 5230 (target-substrate distance (TS distance) The distance is 0.01 m or more and 1 m or less, preferably 0.02 m or more and 0.5 m or less. The deposition chamber is mostly filled with deposition gas (e.g., oxygen, argon, or oxygen in a volume of 5). % or more), and the pressure is 0.01 Pa or more and 100 Pa or less, preferably is controlled to be 0.1 Pa or more and 10 Pa or less. By applying a voltage, a discharge starts and plasma 5240 is observed. A high density plasma region is formed near the nozzle 5230 by the magnetic field. In the region, the deposition gas is ionized to generate ions 5201. , for example, oxygen cations (O + ) and argon cations (Ar + ) etc.

[0281] The target 5230 has a polycrystalline structure having a plurality of crystal grains, and As an example, in FIG. 32, the InMZn 32( ) shows the crystal structure of O4 (element M is, for example, Al, Ga, Y or Sn). A) The crystal structure of InMZnO4 when observed parallel to the b axis. In ZnO4 crystals, the oxygen atoms have a negative charge, so two adjacent M-Zn Therefore, the InMZnO4 crystal has two adjacent M -Zn-O layer has a cleavage plane between them.

[0282] Ions 5201 generated in the high-density plasma region are attracted to the target 5230 by the electric field. The particles are accelerated and eventually collide with the target 5230. At this time, flat or planar particles are formed from the cleavage plane. Pellets 5200, which are pellet-shaped sputtered particles, are peeled off (see FIG. 31). 200 is the portion sandwiched between the two cleavage planes shown in FIG. 32(A). When only 200 is extracted, the cross section looks like Figure 32(B) and the top surface looks like Figure 32(C). It can be seen that the pellet 5200 is formed by the impact of the collision of the ion 5201. This may cause distortion of the structure.

[0283] The pellet 5200 is a flat or pellet-shaped pellet having a triangular, for example, equilateral triangular, plane. Alternatively, the pellet 5200 may have a hexagonal, for example, regular hexagonal, plane. The sputtered particles are in the form of plates or pellets. However, the shape of the pellets 5200 is not limited to triangles or hexagons, for example, when it is a shape made up of multiple triangles For example, a quadrilateral (e.g., a rhombus) is formed by joining two triangles (e.g., an equilateral triangle). ) may also be used.

[0284] The thickness of the pellet 5200 is determined depending on the type of deposition gas. 5200 has a thickness of 0.4 nm or more and 1 nm or less, preferably 0.6 nm or more and 0.8 nm or less. For example, the pellet 5200 has a width of 1 nm or more and 100 nm or less, preferably Preferably, the thickness is 2 nm or more and 50 nm or less, and more preferably, 3 nm or more and 30 nm or less. The target 5230 having In-M-Zn oxide is bombarded with ions 5201. As a result, a pellet 5 having three layers, an M-Zn-O layer, an In-O layer and an M-Zn-O layer, was obtained. As the pellet 5200 peels off, particles are released from the target 5230. Particle 5203 is also ejected. Particle 5203 has a collection of one atom or several atoms. Therefore, particles 5203 are called atomic particles. It is also possible.

[0285] As the pellet 5200 passes through the plasma 5240, its surface becomes negatively or positively charged. For example, when the pellet 5200 is in the plasma 5240, 2- negative charge from As a result, the oxygen atoms on the surface of the pellet 5200 may become negatively charged. In addition, when the pellet 5200 passes through the plasma 5240, It may grow by combining with indium, element M, zinc, or oxygen in 40. .

[0286] The pellets 5200 and particles 5203 that have passed through the plasma 5240 are Some of the particles 5203 are small in mass and can be removed by a vacuum pump or other device. It may be discharged to the outside.

[0287] Next, the deposition of pellets 5200 and particles 5203 on the surface of the substrate 5220 is described. This will be explained using FIG.

[0288] First, the first pellet 5200 is deposited on the substrate 5220. The pellet 5200 is a flat plate. Since the pellet 52 has a shape like a flat surface, it is deposited with the flat surface facing the surface of the substrate 5220. The charge on the surface of 00 on the substrate 5220 side is released through the substrate 5220.

[0289] Next, the second pellet 5200 reaches the substrate 5220. At this time, the already deposited The surface of the first pellet 5200 and the surface of the second pellet 5200 are charged. As a result, the second pellet 5200 is pushed into the pile already. Avoiding the pellets 5200 on which the substrate 5220 is stacked, place the flat side a little away from the surface of the substrate 5220. By repeating this process, countless pellets 52 are deposited on the surface of the substrate 5220. 5200 is deposited to a thickness of one layer. There will be areas where no deposition occurs (see Figure 33(A)).

[0290] Next, the particles 5203 that have received energy from the plasma reach the surface of the substrate 5220. The particles 5203 can be deposited in active areas such as the surface of the pellet 5200. Therefore, the particles 5203 move to the area where the pellet 5200 is not deposited, and the pellet The particle 5203 adheres to the side of the nozzle 5200. The bond becomes more active, and the pellet 5200 is chemically bonded to the lateral growth portion 52 02 (see Figure 33(B)).

[0291] Furthermore, the laterally growing portion 5202 grows in the lateral direction (also called lateral growth), The pellets 5200 are connected to each other (see FIG. 33(C)). Lateral growth 5202 is formed until the undeposited area is filled. Deposition mechanism of atomic layer deposition (ALD) method Similar to a rhythm.

[0292] Therefore, even if the pellets 5200 are piled up in different directions, Particles 5203 grow laterally and fill the gaps between particles 5200, forming clear grain boundaries. In addition, the particles 5203 smoothly connect the pellets 5200. Therefore, a crystal structure different from either single crystal or polycrystal is formed. A crystalline structure having distortion between the crystalline regions (pellets 5200) is formed. The regions filling the gaps are distorted crystalline regions, so it is not appropriate to refer to these regions as amorphous structures. It is considered not to be a good idea.

[0293] Next, a new pellet 5200 is deposited with its flat side facing the surface (see FIG. 33(D)). ) Then, particles 5203 accumulate to fill the undeposited areas of the pellet 5200. By this, the lateral growth portion 5202 is formed (see FIG. 33(E)). 3 adheres to the side of the pellet 5200, and the lateral growth portion 5202 grows laterally. The pellets 5200 in the mth layer are connected (see FIG. 33(F)). The deposition continues until several layers are formed, resulting in a thin film structure having a stack.

[0294] The deposition pattern of the pellets 5200 also changes depending on the surface temperature of the substrate 5220. For example, if the surface temperature of the substrate 5220 is high, the pellet 5200 may be heated to the surface of the substrate 5220. As a result, the pellets 5200 are interdigitated with the particles 5203. The proportion of bonds without any bonds increases, resulting in a CAAC-OS with higher orientation. The surface temperature of the substrate 5220 during the formation of the OS film is set to be equal to or higher than room temperature and lower than 340° C., preferably room temperature. and 300°C or less, more preferably 100°C or more and 250°C or less, and even more preferably 100°C or more and 250°C or less. ℃ or more and 200 ℃ or less. Therefore, the substrate 5220 is a large-area substrate of the 8th generation or more. Even when using a CAAC-OS film, warping and other problems caused by the film formation hardly occur. I understand.

[0295] On the other hand, when the surface temperature of the substrate 5220 is low, the pellet 5200 moves to the surface of the substrate 5220. As a result, pellets 5200 do not pile up. In the case of nc-OS, the pellet 5200 is negatively charged. As a result, the pellets 5200 may be deposited at regular intervals. Although the orientation is low, the film has a slight regularity, which makes it more uniform than an amorphous oxide semiconductor. The entire structure is dense.

[0296] In addition, in CAAC-OS, the gaps between pellets are extremely small, Large pellets of different sizes may be formed. The inside of one large pellet has a single crystal structure. For example, the size of the pellet is 10 nm or more and 200 nm or less when viewed from the top. It may be between 100 nm and 100 nm, or between 20 nm and 50 nm.

[0297] According to the above film formation model, it is believed that pellets are deposited on the surface of the substrate. CAAC-OS can be deposited even on surfaces that do not have a crystalline structure. Therefore, the above-mentioned film formation model, which is a growth mechanism different from epitaxial growth, is highly valid. In addition, because this is the deposition model described above, the CAAC-OS and nc-OS It can be seen that uniform film formation is possible even on large glass substrates. For example, Even if the structure of the substrate surface (surface to be formed) is amorphous (for example, amorphous silicon oxide), It is possible to form a CAAC-OS film.

[0298] In addition, even if the surface of the substrate on which the film is to be formed is uneven, the pellets will adhere to the shape of the uneven surface. It is clear that the arrangement is

[0299] In addition, from the above-mentioned film formation model, the following conditions are required to form a CAAC-OS film with high crystallinity: First, in order to lengthen the mean free path, we need to create a higher vacuum. Next, to reduce damage near the substrate, the plasma energy is Next, heat energy is applied to the surface to be formed, and the damage caused by the plasma is weakened each time a film is formed. It will heal.

[0300] In addition, the above-mentioned film formation model is based on the In-M-Zn oxide target with multiple crystal grains. When a complex oxide has a polycrystalline structure such as a crystalline material, and one of the crystal grains contains a cleavage plane, For example, a mixture of indium oxide, an oxide of element M, and zinc oxide may be used. The present invention can also be applied to the case where an object target is used.

[0301] The target of the mixture does not have a cleavage plane, so when sputtered, atoms are released from the target. During film formation, a strong electric field region of plasma is formed near the target. Therefore, atomic particles detached from the target are connected by the action of the strong electric field region of the plasma. For example, first, atomic particles of indium bond together and grow laterally. Next, M-Zn-O layers are formed above and below it to complement it. Thus, even when a mixed target is used, pellets may be formed. Therefore, even when a target made of a mixture is used, the above-mentioned film formation model can be applied. It is possible.

[0302] However, if a strong electric field region of the plasma is not formed near the target, Only atomic particles peeled off from the substrate are deposited on the substrate surface. In this case, atomic particles may grow laterally. However, because the orientation of atomic particles is not uniform, However, the crystal orientation in the resulting thin film is not uniform. .

[0303] (Embodiment 6) In this embodiment, a transistor having a different structure from the transistor described in Embodiment 1 is used. The configuration will be described with reference to FIGS.

[0304] <Transistor configuration example 1> 34(A) is a top view of transistor 270, and FIG. 34(B) is a top view of transistor 270. 34(C) corresponds to a cross-sectional view of the cut surface taken along the dashed line X1-X2 shown in FIG. This corresponds to the cross-sectional view of the cut surface taken along the dashed line Y1-Y2 shown in (A). The X1-X2 direction is called the channel length direction, and the dashed dotted line Y1-Y2 direction is called the channel width direction. There are cases where this happens.

[0305] The transistor 270 includes a conductive film 204 over a substrate 202, which functions as a first gate electrode. an insulating film 206 on the substrate 202 and the conductive film 204; and an insulating film 207 on the insulating film 206. The oxide semiconductor film 208 over the insulating film 207 and the insulating film 208 electrically connected to the oxide semiconductor film 208 The conductive film 212a serving as a source electrode and the oxide semiconductor film 208 are electrically connected to each other. The conductive film 212b functions as a drain electrode connected to the oxide semiconductor film 208, the conductive film 21 The insulating films 214 and 216 on the conductive film 212a and the conductive film 212b, and the oxide semiconductor film on the insulating film 216 An insulating film 218 is provided over the oxide semiconductor film 211b.

[0306] In the transistor 270, the insulating film 214 and the insulating film 216 are The oxide semiconductor film 211a functions as a second gate insulating film of the oxide semiconductor film 211b. The conductive film 212b and the insulating film 212c are formed through the openings 252c formed in the insulating films 214 and 216. The oxide semiconductor film 211a functions as, for example, a pixel electrode used in a display device. In the transistor 270, the oxide semiconductor film 211b has a second gate It functions as a gate electrode (also called a back gate electrode).

[0307] As shown in FIG. 34C, the oxide semiconductor film 211b is formed by insulating films 206 and 207. In the openings 252a and 252b provided in the insulating film 214 and the insulating film 216, the first The conductive film 220b is connected to the conductive film 204 that functions as a gate electrode. The same potential is applied to the semiconductor film 211b.

[0308] In this embodiment, the openings 252a and 252b are provided, and the oxide semiconductor film 2 Although the configuration in which 11b and the conductive film 204 are connected has been exemplified, the present invention is not limited to this. , only one of the openings 252a and 252b is formed, and an oxide semiconductor The conductive film 211b and the conductive film 204 are connected to each other, or the opening 252a and the opening 252b are connected to each other. Alternatively, the oxide semiconductor film 211b and the conductive film 204 may not be connected to each other by providing no portion b. In the case where the oxide semiconductor film 211b and the conductive film 204 are not connected to each other, Different potentials can be applied to the conductive film 211b and the conductive film 204, respectively.

[0309] As shown in FIG. 34B, the oxide semiconductor film 208 is used as a first gate electrode. The conductive film 204 functions as a gate electrode, and the oxide semiconductor film 211b functions as a second gate electrode. They are positioned opposite each other and are sandwiched between two conductive films that function as gate electrodes. The length in the channel length direction of the oxide semiconductor film 211b functioning as the second gate electrode and The length in the channel width direction is the length in the channel length direction of the oxide semiconductor film 208 and the channel width The length of the oxide semiconductor film 208 is longer than the length in each direction. The gate electrode is covered with the oxide semiconductor film 211b via the film 216. The oxide semiconductor film 211b functioning as a gate electrode and the conductive film 204 functioning as a first gate electrode are , an opening 252a provided in the insulating films 206, 207, the insulating film 214, and the insulating film 216; Since the oxide semiconductor film 208 is connected at the insulating layer 252b, the side surface of the oxide semiconductor film 208 in the channel width direction is The oxide semiconductor film 2 functions as a second gate electrode via the insulating film 214 and the insulating film 216. It faces 11b.

[0310] In other words, in the channel width direction of the transistor 270, The conductive film 204 and the oxide semiconductor film 211b functioning as the second gate electrode are Insulating films 206 and 207 functioning as first gate insulating films and The insulating film 214 and the insulating film 216 are connected in openings formed therein, and the first The insulating films 206 and 207 functioning as the first gate insulating film and the second gate insulating film The oxide semiconductor film 208 is surrounded by the insulating film 214 and the insulating film 216. .

[0311] With such a structure, the oxide semiconductor film 208 included in the transistor 270 The conductive film 204 functions as a first gate electrode and the conductive film 205 functions as a second gate electrode. The transistor 270 can be electrically surrounded by the electric field of the oxide semiconductor film 211b. As shown above, a channel region is formed by the electric field of the first gate electrode and the second gate electrode. The device structure of the transistor that electrically surrounds the oxide semiconductor film to be formed is This can be called a d channel (s-channel) structure.

[0312] Since the transistor 270 has an s-channel structure, The conductive film 204 functions as a gate electrode, and the electric field for inducing the channel is effectively applied to the oxide semiconductor. This allows the voltage to be applied to the body membrane 208, improving the current driving capability of the transistor 270. It is possible to obtain high on-current characteristics. It is also possible to increase the on-current. Therefore, it is possible to miniaturize the transistor 270. The conductive film 204 functions as a first gate electrode and the oxide film 205 functions as a second gate electrode. Since the transistor 270 has a structure surrounded by the nitride semiconductor film 211b, Strength can be increased.

[0313] <Transistor configuration example 2> Next, regarding a configuration example different from that of the transistor 270 shown in FIGS. 34(A), (B), and (C), The explanation will be given using Figures 35(A), (B), (C), and (D). Figures 35(A) and (B) are the same as Figure 34(B). 35(C)(D) are cross-sectional views of a modified example of the transistor 270 shown in FIG. 34(B)(C) is a cross-sectional view of a modified example of the transistor 270 shown in FIG.

[0314] The transistor 270A shown in FIGS. 35(A) and 35(B) is the same as the transistor 270A shown in FIGS. 34(B) and 34(C). The oxide semiconductor film 208 included in the transistor 270 has a three-layer structure. The oxide semiconductor film 208 included in the transistor 270A is an oxide semiconductor film 208a. , an oxide semiconductor film 208b, and an oxide semiconductor film 208c.

[0315] The transistor 270B shown in FIGS. 35(C) and 35(D) is the same as the transistor shown in FIGS. 34(B) and 34(C). The oxide semiconductor film 208 included in the transistor 270 has a two-layer structure. The oxide semiconductor film 208 included in the transistor 270B is the oxide semiconductor film 208b. , and an oxide semiconductor film 208c.

[0316] The structures of the transistors 270, 270A, and 270B shown in this embodiment are the same as those of the transistors 270, 270A, and 270B shown in this embodiment. The structure of the liquid crystal display device described in 1 can be referred to. That is, the material and manufacturing method of the substrate 202 The material and manufacturing method of the conductive film 204 can be the same as those of the gate electrode 104. The materials and manufacturing methods of the insulating film 206 and the insulating film 207 are the same as those of the insulating film 1 The oxide semiconductor film 208 can be formed by the method described in the first The oxide semiconductor film 211a and the oxide semiconductor film 21 The material and formation method of the conductive film 212a can be referred to those of the second oxide semiconductor film 111. The material and manufacturing method of the conductive film 212b are the source electrode 112a and the drain electrode 112b, respectively. Materials and Fabrication of the Insulating Film 214, Insulating Film 216, and Insulating Film 218 The methods can refer to the insulating film 114, the insulating film 116, and the insulating film 118, respectively.

[0317] Here, the band structure of the oxide semiconductor film 208 and the insulating film in contact with the oxide semiconductor film 208 is The structure will be explained with reference to FIG.

[0318] FIG. 36A shows the insulating film 207, the oxide semiconductor films 208a, 208b, and 208c, and This is an example of a band structure in the film thickness direction of a laminated structure having an insulating film 214. ) is a multilayer structure including the insulating film 207, the oxide semiconductor films 208b and 208c, and the insulating film 214. This is an example of a band structure in the film thickness direction of a layer structure. Therefore, the insulating film 207, the oxide semiconductor films 208a, 208b, and 208c, and the insulating film 214 are electrically conductive. The energy level (Ec) at the bottom of the conductive band is shown.

[0319] In addition, in FIG. 36(A), silicon oxide films are used as the insulating films 207 and 214, and oxide semiconductor The conductor film 208a is a metal oxide film having an atomic ratio of metal elements of In:Ga:Zn=1:1:1.2. The oxide semiconductor film 208b was formed using an oxide semiconductor film formed using an oxide target. A metal oxide target with an atomic ratio of In:Ga:Zn=4:2:4.1 was used. The oxide semiconductor film 208c is formed by using an oxide semiconductor film having a metal element number of 100 or less. The oxide formed using a metal oxide target with a ratio of In:Ga:Zn=1:1:1.2 FIG. 1 is a band diagram of a structure using a compound semiconductor film.

[0320] In addition, in FIG. 36(B), silicon oxide films are used as the insulating films 207 and 214, and oxide semiconductor films are used. The conductor film 208b is a metal oxide film having an atomic ratio of In:Ga:Zn=4:2:4.1. The oxide semiconductor film 208c was formed using an oxide semiconductor film formed using an oxide target. A metal oxide target with an atomic ratio of In:Ga:Zn=1:1:1.2 was used. FIG. 10 is a band diagram of a structure using an oxide semiconductor film formed by

[0321] As shown in FIGS. 36A and 36B, in the oxide semiconductor films 208a, 208b, and 208c, In other words, the energy level at the bottom of the conduction band changes smoothly. In order to have such a band structure, the oxide The interface between the oxide semiconductor film 208a and the oxide semiconductor film 208b, or the oxide semiconductor film 208b At the interface between the oxide semiconductor film 208c and the oxide semiconductor film 208b, defect quasi-crystallization occurs, such as a trap center or a recombination center. Assume that there are no impurities that would form positions.

[0322] In order to form a continuous junction in the oxide semiconductor films 208a, 208b, and 208c, Each film is deposited using a multi-chamber deposition system (sputtering system) equipped with a lock chamber. It is necessary to continuously stack the layers without exposing them to the air.

[0323] By using the structure shown in FIGS. 36A and 36B, the oxide semiconductor film 208b forms a well. In the transistor using the above stacked structure, the channel region is formed of the oxide semiconductor film 2 It can be seen that it is formed in 08b.

[0324] Note that by providing the oxide semiconductor films 208a and 208c, the oxide semiconductor film 208 Therefore, trap states that may be formed in the oxide semiconductor film 208b can be kept away from the oxide semiconductor film 208b.

[0325] In addition, the trap states are below the conduction band of the oxide semiconductor film 208b which functions as a channel region. The energy level (Ec) at the edge of the trap is farther from the vacuum level, making it easier for electrons to accumulate in the trap level. When electrons accumulate in the trap level, the negative charge is fixed. This results in a charge, and the threshold voltage of the transistor shifts in the positive direction. The trap level is lower than the energy level (Ec) of the conduction band minimum of the oxide semiconductor film 208b. It is preferable to configure the trap level so that it is close to the empty level. This makes it difficult for electrons to accumulate, which increases the on-state current of the transistor. , the field effect mobility can be increased.

[0326] The oxide semiconductor films 208a and 208c have a conduction band lower than that of the oxide semiconductor film 208b. The energy level of the edge is close to the vacuum level, and typically, and the energy levels of the conduction band minimums of the oxide semiconductor films 208a and 208c. The difference between the two is 0.15 eV or more, or 0.5 eV or more and 2 eV or less, or 1 eV That is, the electron affinity of the oxide semiconductor films 208a and 208c and the The difference between the electron affinity of the organic film 208b and the electron affinity of the organic film 208c is 0.15 eV or more, or 0.5 eV or more, and eV or less, or 1 eV or less.

[0327] With such a structure, the oxide semiconductor film 208b serves as a main current path. That is, the oxide semiconductor film 208b functions as a channel region, and the oxide semiconductor film 2 The oxide semiconductor film 208a and 208c function as oxide insulating films. a and 208c are metal elements constituting the oxide semiconductor film 208b in which the channel region is formed. Since the oxide semiconductor film 208a is made of one or more of the oxide semiconductor films 208a and 208b, The interface between the oxide semiconductor film 208b and the oxide semiconductor film 208c or the interface between the oxide semiconductor film 208b and the oxide semiconductor film 208c Therefore, the movement of carriers at the interface is Since the electrons are not blocked, the field effect mobility of the transistor is increased.

[0328] In addition, the oxide semiconductor films 208a and 208c function as part of a channel region. To prevent this, a material with sufficiently low conductivity is used. The films 208a and 208c are also called oxide insulating films based on their physical properties and / or functions. In addition, the oxide semiconductor films 208a and 208c have a high electron affinity (vacuum level and the energy level at the bottom of the conduction band) is smaller than that of the oxide semiconductor film 208b, The energy level of the bottom of the conduction band of the oxide semiconductor film 208b is different from the energy level of the bottom of the conduction band of the oxide semiconductor film 208b ( The material used should have a band offset. In order to suppress the difference in threshold voltage between the oxide semiconductor films 208a and 208b, The energy level of the conduction band minimum of the oxide semiconductor film 208c is higher than that of the oxide semiconductor film 208b. It is preferable to use a material whose temperature is closer to the vacuum level than the Gamma level. For example, The energy level of the conduction band minimum of the oxide semiconductor films 208a and 208c is The difference in energy level between the I wish.

[0329] In addition, the oxide semiconductor films 208a and 208c do not contain a spinel crystal structure. It is preferable that the oxide semiconductor films 208a and 208c have a spinel crystal structure. When the spinel type crystal structure is contained, the conductive film 212a, 21 The constituent elements of 2b may diffuse into the oxide semiconductor film 208b. When the conductive films 208a and 208c are made of CAAC-OS, the structure of the conductive films 212a and 212b is This is preferable because it increases the blocking property of the component element, for example, copper element.

[0330] The thicknesses of the oxide semiconductor films 208a and 208c are determined by the amount of the constituent elements of the conductive films 212a and 212b. The insulating film has a thickness that is greater than or equal to a thickness that can prevent the insulating film from diffusing into the oxide semiconductor film 208b. The thickness of the oxide semiconductor film 208b is set to be less than the thickness that prevents oxygen from being supplied from the film 214 to the oxide semiconductor film 208b. When the thickness of the oxide semiconductor films 208a and 208c is 10 nm or more, the conductive film 212a This can prevent the constituent elements of the oxide semiconductor film 212b from diffusing into the oxide semiconductor film 208b. In addition, when the thickness of the oxide semiconductor films 208a and 208c is 100 nm or less, the insulating film 214 Oxygen can be effectively supplied from the oxide semiconductor film 208b to the oxide semiconductor film 208b.

[0331] In this embodiment, the oxide semiconductor films 208a and 208c are formed by adding a metal element. The atomic ratio of In:Ga:Zn was 1:1:1.2. However, the present invention is not limited to this. The compound semiconductor films 208a and 208c are made of In:Ga:Zn=1:1:1 [atomic ratio], In:Ga:Zn=1:3:2 [atomic ratio], In:Ga:Zn=1:3:4 [atomic ratio] ], or a metal oxide target with In:Ga:Zn=1:3:6 [atomic ratio] A formed oxide semiconductor film may be used.

[0332] The oxide semiconductor films 208a and 208c were formed using a compound of In:Ga:Zn=1:1:1 [primary When a metal oxide target having a molecular weight ratio of 0.1 to 0.2 is used, the oxide semiconductor films 208a and 208c have a In:Ga:Zn=1:β1(0<β1≦2):β2(0<β2≦3) The oxide semiconductor films 208a and 208c are formed of In:Ga:Zn=1:3:4 [atomic When a metal oxide target having a molecular weight ratio of 0.1 to 0.2 is used, the oxide semiconductor films 208a and 208c have a In:Ga:Zn=1:β3(1≦β3≦5):β4(2≦β4≦6) The oxide semiconductor films 208a and 208c are made of In:Ga:Zn=1:3:6 [atomic When a metal oxide target having a molecular weight ratio of 0.1 to 0.2 is used, the oxide semiconductor films 208a and 208c have a In:Ga:Zn=1:β5(1≦β5≦5):β6(4≦β6≦8) .

[0333] In addition, the oxide semiconductor film 208 included in the transistor 270 and the transistor 270A The oxide semiconductor film 208c in the region 270B is the conductive film 212a. The oxide semiconductor film in the region not overlapping with b becomes thinner. In other words, part of the oxide semiconductor film becomes concave. However, one embodiment of the present invention is not limited to this. The oxide semiconductor film in the region not overlapping with the conductive films 212a and 212b does not necessarily have to have a recess. An example of this case is shown in Figures 37(A) and 37(B). 37A and 37B are cross-sectional views showing examples of the transistor 270B shown above. The oxide semiconductor film 208 has no recessed portion.

[0334] As shown in FIGS. 37C and 37D, the thickness of the oxide semiconductor film 208c is set to 1000 nm by pre-oxidizing the oxide semiconductor film 208c. The oxide semiconductor film 208c and the insulating film 207 are formed thinner than the oxide semiconductor film 208b. In this case, the insulating film 219 may be formed over the oxide semiconductor film 208. The insulating film 219 is formed with openings so that the insulating film 219 is in contact with the conductive film 212a and the conductive film 212b. The insulating film 214 can be formed using the same material and method as the insulating film 214 .

[0335] In addition, the transistor according to this embodiment can be freely combined with each of the above structures. It is possible to do this.

[0336] As described above, the structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiments. They can be used in combination.

[0337] (Embodiment 7) In this embodiment, a structure of a display device according to one embodiment of the present invention will be described with reference to FIGS. 38 to 45. Explain with reference to the above.

[0338] <Display device configuration example 1.> FIG. 38 is a top view illustrating a structure of a display device according to one embodiment of the present invention. 1 is a top view illustrating a structure of a pixel included in a display device according to one embodiment of the present invention.

[0339] FIG. 40 shows the cross-sectional view of the present invention taken along the cutting lines Z1-Z2, Z3-Z4, and Z5-Z6 shown in FIG. FIG. 1 is a cross-sectional view illustrating a cross-sectional configuration of a display device according to one embodiment.

[0340] FIG. 41(A) shows the main part along the cutting lines Z1-Z2, Z3-Z4, and Z5-Z6 shown in FIG. FIG. 10 is a cross-sectional view illustrating a cross-sectional structure of a first display portion 700E of a display device according to one embodiment of the invention; FIG. 41B is a cross-sectional view illustrating a structure of a transistor.

[0341] FIG. 42 shows the cross-sectional view of the present invention taken along the cutting lines Z1-Z2, Z3-Z4, and Z5-Z6 shown in FIG. FIG. 10 is a cross-sectional view illustrating a cross-sectional configuration of a second display section 500E of the display device according to one embodiment.

[0342] The display device described in this embodiment includes a pixel 702E and a substrate 710 (see FIG. 3). 8, 39 and 40). The element 702ER can be used for the pixel 702E.

[0343] The substrate 710 functions to support the pixel 702E (see FIG. 40).

[0344] The pixel 702E has a first display element 750EB and an area overlapping the first display element 750EB. and a second display element 550EB having a first area (see FIGS. 39 and 40).

[0345] The first display element 750EB includes a reflective film (first conductive film 751EB) that reflects external light and The reflective film (first conductive film 751EB) has a function of controlling the transmission of light from the outside. Equipped with 51H.

[0346] The second display element 550EB has a region overlapping with the opening 751H and a region facing the opening 751H. It has the function of emitting light.

[0347] The first display element 750EB includes a liquid crystal layer 753, a first conductive film 751EB, and a second conductive film 751EB. The conductive film 752 is provided (see FIG. 41).

[0348] The second display element 550EB includes a layer 553E containing a light-emitting organic compound, a third conductive film 5 51EB and a fourth conductive film 552 (see FIG. 42).

[0349] The opening 751H has an area of, for example, 5% to 35% of the area of ​​the first conductive film 751EB. Preferably, the area is 15% or more and 25% or less.

[0350] The second display element 550EB emits light to an area that is shaped to substantially overlap with the opening 751H. The area that is roughly overlapped with the opening 751H has the function of The area of ​​the region that does not overlap with the opening 751H is The area is 20% or less, preferably 10% or less, of the area of ​​the overlapping region.

[0351] Specifically, the area from which the light of the second display element 550EB is emitted is equal to the area of ​​the opening 751H. an area of ​​0.5 times or more and less than 1.5 times, preferably an area of ​​0.8 times or more and less than 1.2 times, Preferably, the area is 0.9 times or more and less than 1.1 times.

[0352] The display device includes a subpixel 702EB and a substrate 710 that supports the subpixel 702EB. On the other hand, the sub-pixel 702EB uses a reflective film having an opening 751H as the first conductive film 751EB. a first display element 750EB (for example, a reflective liquid crystal element) facing the opening 751H; and a second display element 550EB (for example, an organic EL element) that emits light. can be.

[0353] This allows the display device to be used as a reflective display device, for example, in an environment with strong external light. This allows the device to be used as a self-luminous display device, for example, in a dimly lit environment. As a result, a novel display device with reduced power consumption and excellent convenience and reliability is provided. It is possible.

[0354] In addition, an insulating film is provided between two pixel electrodes between adjacent sub-pixels. The first conductive film 751EB of the subpixel 702EB and the second conductive film 751EB of the subpixel 702EG are An insulating film 777 is provided between the first conductive films 751EG. The conductive film 751EB and the first conductive film 751EG are insulated from each other, so that the top surface shape of the conductive film 751EB is the same as that of the first conductive film 751EG. It is possible to eliminate a gap between the first conductive film 751EB and the first conductive film 751EG. By adopting such a configuration, the aperture ratio of the pixels of the first display section 700E can be increased. In addition, by increasing the aperture ratio of the pixel, the contrast of the image displayed by the first display unit 700E can be improved. This allows for higher cost and brighter displayed images.

[0355] <Configuration> The display device according to one embodiment of the present invention includes a first display portion 700E, a second display portion 500E, and a connection It has a bonding layer 535 (see Figures 38 and 40).

[0356] <<First display unit 700E>> The first display unit 700E includes a pixel unit, a wiring unit, a source driver circuit unit SD1, a gate driver It has a buffer circuit section GD1 and a terminal section (see FIGS. 38 and 41).

[0357] The first display unit 700E includes a substrate 710, a substrate 770, a structure KB1, a liquid crystal layer 75, and a 3. The sealing material 730 and the optical film 770P are included.

[0358] Substrate 770 has an area that overlaps substrate 710 .

[0359] The sealant 730 has a function of bonding the substrate 710 and the substrate 770 together.

[0360] The liquid crystal layer 753 is disposed in an area surrounded by the substrate 710, the substrate 770, and the sealant 730. will be done.

[0361] The structure KB1 is disposed between the substrate 710 and the substrate 770. The function is to form a gap of a predetermined distance between the substrate 710 and the substrate 770.

[0362] 《Pixel section》 The pixel portion includes a pixel 702E, an insulating film 771, an insulating film 721A, an insulating film 721B, and an insulating film 7 Equipped with 28.

[0363] For example, multiple sub-pixels can be used for pixel 702E. a subpixel 702EB that displays green, a subpixel 702EG that displays red, and 702ER, etc. can be used. In addition, a sub-pixel for displaying white or a sub-pixel for displaying yellow can be used. A sub-pixel or the like can be used.

[0364] For example, if the area of ​​the pixel that displays blue is made larger than the area of ​​the pixel that displays other colors, This makes it possible to display white in a suitable manner.

[0365] 《Pixels》 The subpixel 702EB includes a first display element 750EB, a colored film CFB1, and a pixel circuit. do.

[0366] "First display element 750EB" For example, a display element having a function of controlling reflection or transmission of light may be used as the first display element 750. For example, it can be used in a combination of a liquid crystal element and a polarizing plate, or in a shutter. A display element such as a MEMS display element of the mirror type can be used.

[0367] Specifically, IPS (In-Plane-Switching) mode, TN (Twi Sted Nematic) mode, FFS (Fringe Field Switch) ing) mode, ASM(Axially Symmetric aligned Mi cro-cell mode, OCB (Optically Compensated B refrigeration mode, FLC (Ferroelectric Liquid d Crystal) mode, AFLC (AntiFerroelectric Liq. Liquid crystal element that can be driven using a driving method such as uid Crystal mode can be used.

[0368] In addition, for example, a vertical alignment (VA) mode, specifically, an MVA (Multi-Domain) n Vertical Alignment) mode, PVA(Patterned V Driven using drive methods such as Vertical Alignment mode and ASV mode A liquid crystal element that can be moved can be used.

[0369] For example, thermotropic liquid crystal, low molecular weight liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal, ferroelectric These liquid crystal materials can be used in various applications, such as ferroelectric liquid crystals and antiferroelectric liquid crystals. esteric phase, smectic phase, cubic phase, chiral nematic phase, isotropic phase, etc. Alternatively, a liquid crystal material exhibiting a blue phase can be used. Cut.

[0370] For example, a liquid crystal layer 753 containing a liquid crystal material may be formed so that an electric field can be applied to control the orientation of the liquid crystal material. The semiconductor device includes a first conductive film 751EB and a second conductive film 752 arranged as shown in FIG.

[0371] A conductive material can be used for the first conductive film 751EB.

[0372] For example, the material used for the wiring portion is used for the first conductive film 751EB or the second conductive film 752. You can be there.

[0373] For example, a material that reflects light incident from the liquid crystal layer 753 side is used for the first conductive film 751EB. This allows the first display element 750EB to be a reflective liquid crystal element. The first conductive film 751EB functions as a pixel electrode.

[0374] For example, a conductive film having an uneven surface may be used as the first conductive film 751EB. This allows the incoming light to be reflected in various directions, resulting in a white display. .

[0375] For example, a material that transmits visible light and has conductivity is used for the second conductive film 752. It can be used for.

[0376] For example, a conductive oxide or a conductive oxide containing indium is used for the second conductive film 752. Alternatively, a metal film thin enough to transmit light may be used as the second conductive film 752. It is possible.

[0377] Specifically, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide The second conductive film 752 can be formed using zinc oxide doped with gallium, or the like.

[0378] 《Opening 751H》 The first display portion 700F has an opening 751H in the first conductive film 751EB. A part of the light incident from the opening 751H passes through the opening 751H and can be emitted from the substrate 770. Cut.

[0379] The area of ​​the first conductive film 751EB is 5% or more and 35% or less, preferably 15% or more and 25% or less. The lower side is preferable for the area of ​​the opening 751H.

[0380] The shape of the opening 751H may be a polygon, a rectangle, an ellipse, a circle, a cross, or the like. This can be done.

[0381] "First colored film" The first colored film has an area overlapping with the first display element 750EB and transmits light of a predetermined color. The colored film can be used, for example, as a color filter.

[0382] For example, the colored film CFB1 that transmits blue light can be used for the subpixel 702EB. A colored film CFG1 that transmits green light can be used for the sub-pixel 702EG. A colored film that transmits light can be used for the sub-pixel 702ER. Colored films that transmit yellow light and colored films that transmit yellow light are used as sub-pixels to display various colors. It is possible.

[0383] 《Light blocking film BM》 A light-shielding film BM having an opening in an area overlapping with the sub-pixel 702EB may be provided.

[0384] A material that blocks light transmission can be used for the light-shielding film BM. , which functions as, for example, a black matrix.

[0385] 《Pixel circuit》 The transistor ME1 or the capacitance element C1 can be used in the pixel circuit.

[0386] The transistor ME1 has a semiconductor film 718 and a conductive film having an area overlapping the semiconductor film 718. The transistor ME1 has a conductive film 712 (see FIG. 41B). A and a conductive film 712B.

[0387] The conductive film 712A has either a function of a source electrode or a function of a drain electrode. The conductive film 712B has the function of either a source electrode or a drain electrode. The film 704 functions as a gate electrode, and the insulating film 706 functions as a gate insulating film.

[0388] The semiconductor material used for the semiconductor film 718 is not particularly limited. For example, an oxide semiconductor, a silicon The crystallinity of the semiconductor materials used in transistors is also The semiconductor material is not particularly limited, and may be an amorphous semiconductor, a crystalline semiconductor (microcrystalline semiconductor, polycrystalline semiconductor, Any of a solid semiconductor, a single crystal semiconductor, and a semiconductor having a crystalline region in part may be used. It is preferable to use a semiconductor having such a property, since this can prevent the deterioration of the transistor characteristics.

[0389] Semiconductor materials used in transistors include, for example, elements of Group 14, compound semiconductors, and the like. A conductor or an oxide semiconductor can be used for the semiconductor layer. A conductor, a semiconductor containing gallium arsenide, an oxide semiconductor containing indium, or the like can be used.

[0390] In particular, an oxide semiconductor can be used as a semiconductor in which a channel of a transistor is formed. It is particularly preferable to use an oxide semiconductor having a larger band gap than silicon. It is preferable to use a semiconductor material with a wider band gap and lower carrier density than silicon. The use of such a compound is preferable because it can reduce the current in the off state of the transistor.

[0391] For example, the transistor using an oxide semiconductor is described in Embodiment 1 or 6. The transistor described in can be used as the transistor ME1.

[0392] The capacitance element C1 includes a conductive film 712A and a conductive film having an area overlapping the conductive film 712A. (See Figure 41(A)).

[0393] The conductive film 712A is electrically connected to the first conductive film 751EB.

[0394] <Insulating film> The insulating film 771 is disposed between the liquid crystal layer 753 and the colored films CFB1 and CFG1.

[0395] A material that has the function of suppressing the diffusion of impurities from the colored film CFB1 etc. to the liquid crystal layer 753 It can be used for the insulating film 771.

[0396] The insulating film 721B has a region overlapping with the conductive film 704 and a region overlapping with the semiconductor film 718. can.

[0397] The insulating film 721A is disposed between the semiconductor film 718 and the insulating film 721B (FIG. 41( See Figure 41(A) and Figure 41(B).

[0398] "Insulating Film 728" The insulating film 728 is disposed between the insulating film 721B and the liquid crystal layer 753.

[0399] The insulating film 728 serves to flatten steps resulting from various structures that overlap with the insulating film 728. This allows the thickness of the liquid crystal layer 753 to be uniform.

[0400] For example, insulating inorganic materials, insulating organic materials, or insulating materials containing inorganic and organic materials. The composite material can be used for the insulating film 728 (see FIG. 41A).

[0401] Specifically, inorganic oxide films, inorganic nitride films, inorganic oxynitride films, or films made of these The insulating film 728 can be formed by stacking a plurality of selected materials.

[0402] Specifically, polyester, polyolefin, polyamide, polyimide, polycarbonate polysiloxane, acrylic resin, or a plurality of resins selected from these A laminated material, a composite material, or the like can be used for the insulating film 728. The insulating film may be formed using a material that can be used.

[0403] "Insulating Film 777" The insulating film 777 is provided to cover the edge of one pixel electrode. The first conductive film 751EG is provided so as to cover the end of the first conductive film 751EG (see FIGS. 39 and 40). It is provided so as to cover the end of the membrane 751ER (see FIG. 39).

[0404] <<Source driver circuit section SD1>> For example, an integrated circuit can be used for the source driver circuit section SD1. An integrated circuit formed on a silicon substrate can be used (see FIG. 38).

[0405] For example, a chip on glass (COG) method is used to form a semiconductor device on the substrate 710. The source driver circuit section SD1 can be mounted on the pad. The pads are electrically connected to pixel circuits.

[0406] <Gate driver circuit GD1> For example, the transistor ME2 can be used in the gate driver circuit section GD1 (FIG. 4 1(A) and Figure 41(B)).

[0407] For example, the transistor described in the first embodiment or the sixth embodiment may be a transistor ME It can be used for 2.

[0408] For example, the semiconductor film 718 of the transistor ME1 can be formed in the same process. A semiconductor film capable of forming a semiconductor film can be used for the transistor ME2.

[0409] The same configuration as that of the transistor ME1 can be used for the transistor ME2. Also, different configurations can be used for transistor ME2.

[0410] Conductive film 720 The conductive film 720 has a region overlapping with the semiconductor film 718. In other words, the conductive film 720 has a region overlapping with the semiconductor film 718. is disposed between the conductive film 720 and the conductive film 704. Alternatively, the characteristics or reliability of the transistor ME2 can be improved.

[0411] The conductive film 720 can be used as the second gate electrode of the transistor ME2. 720 can also be referred to as a part of transistor ME1 or transistor ME2.

[0412] For example, the conductive film 720 is electrically connected to a wiring that can supply the same potential as the conductive film 704. can be connected to.

[0413] For example, the material used for the wiring portion can be used for the conductive film 720. conductive oxides or conductive oxides containing indium, indium oxide, indium tin oxide, Indium zinc oxide, indium zinc gallium oxide, zinc oxide, gallium doped The conductive film 720 can be made of zinc oxide or the like.

[0414] 《Wiring section, terminal section》 The wiring portion includes a signal line 711. The terminal portion includes a connection electrode 719 (FIG. 41(A)). reference).

[0415] The signal line 711 is electrically connected to the connection electrode 719. It can be used for the connection electrode 719.

[0416] The connection electrode 719 is formed on the flexible printed circuit board FP using, for example, a conductive member ACF1. Electrically connected to C1.

[0417] A conductive material can be used for the signal line 711 and the connection electrode 719 .

[0418] For example, inorganic conductive materials, organic conductive materials, metals, conductive ceramics, etc. It can be used for the wire 711 or the connecting electrode 719 .

[0419] Specifically, aluminum, gold, platinum, silver, copper, chromium, tantalum, titanium, molybdenum gold, selected from nickel, iron, cobalt, palladium, and manganese; Metal elements can be used for the signal line 711 or the connection electrode 719. An alloy containing the above metal element can be used for the signal line 711 or the connection electrode 719. In particular, an alloy of copper and manganese is suitable for microfabrication using wet etching.

[0420] Specifically, a two-layer structure in which a titanium film is laminated on an aluminum film, a titanium nitride film on a titanium nitride film, Two-layer structure with a tungsten film laminated on a titanium nitride film, two-layer structure with a tungsten film laminated on a titanium nitride film, Two-layer structure in which a tungsten film is laminated on a titanium film or a tungsten nitride film, A three-layer structure is formed in which an aluminum film is laminated on the titanium film, and a titanium film is further formed on the aluminum film. The structure can be used for the signal line 711 or the connection electrode 719 .

[0421] Specifically, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide , a conductive oxide such as zinc oxide doped with gallium is used for the signal line 711 or the connection electrode 71 It can be used for 9.

[0422] Specifically, a film containing graphene or graphite is formed on the signal line 711 or the connection electrode 7 It can be used for 19.

[0423] For example, by forming a film containing graphene oxide and reducing the film containing graphene oxide, As a result, a film containing graphene can be formed. and a method using a reducing agent.

[0424] Specifically, a conductive polymer can be used for the signal line 711 or the connection electrode 719. .

[0425] Conductive material ACF1 For example, solder, conductive paste, anisotropic conductive film, etc. may be used for the conductive member ACF1. This can be done.

[0426] Specifically, conductive particles and a material for dispersing the particles are used in the conductive member ACF1. It is possible.

[0427] For example, spheres with a size of 1 μm or more and 200 μm or less, preferably 3 μm or more and 150 μm or less Particles having shapes such as crystalline, columnar, or filler shapes can be used.

[0428] For example, particles coated with conductive materials, including nickel or gold, can be used. do.

[0429] Specifically, particles containing polystyrene, acrylic resin, titanium oxide, etc. are used. can be done.

[0430] For example, synthetic rubber, thermosetting resin, thermoplastic resin, etc. can be used as the material for dispersing particles. This can be done.

[0431] As a result, the flexible printed circuit board FPC1 and the connection electrode 719 are electrically connected using the particles. can be effectively connected.

[0432] <<Board 710>> A light-transmitting material can be used for the substrate 710. In addition, the thickness can be reduced by polishing. A variety of materials can be used for the substrate 710 .

[0433] For example, a laminated material of a base material 710A and an insulating film 710B is used for the substrate 710. 0B has the function of suppressing the diffusion of impurities contained in the base material 710A or impurities from the outside. Prepare.

[0434] The substrate 710 may be made of a material having heat resistance sufficient to withstand heat treatment during the manufacturing process. can.

[0435] For example, 6th generation (1500mm x 1850mm), 7th generation (1870mm x 220 0mm), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 280 10th generation (2950mm x 3400mm) and other large glass substrates. This can be used for the plate 710. This makes it possible to manufacture a large display device.

[0436] The substrate 710 may be made of an organic material, an inorganic material, or a composite material of an organic material and an inorganic material. For example, inorganic materials such as glass, ceramics, and metals can be used for the substrate 710. This can be done.

[0437] Specifically, non-alkali glass, soda-lime glass, potash glass, crystal glass, Quartz, sapphire, or the like can be used for the substrate 710. Specifically, inorganic oxides A film, an inorganic nitride film, an inorganic oxynitride film, or the like can be used for the substrate 710. For example, , silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, etc., is used as the substrate 710. The substrate 710 can be made of SUS or aluminum. do.

[0438] For example, a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a silicon A compound semiconductor substrate such as a germanium substrate, an SOI substrate, or the like can be used for the substrate 710. This allows semiconductor elements to be formed on the substrate 710.

[0439] For example, organic materials such as resin, resin film, or plastic may be used for the substrate 710. Specifically, polyester, polyolefin, polyamide, polyimide, A resin film or plate such as polycarbonate or acrylic resin is used as the substrate 710. It is possible.

[0440] For example, a metal plate, a thin glass plate, or a film of an inorganic material is laminated to a resin film. A composite material containing the metal particles can be used for the substrate 710. For example, a fibrous or particulate metal, A composite material in which glass or inorganic material is dispersed in a resin film is used for the substrate 710. For example, fibrous or particulate resin or organic material can be dispersed in an inorganic material. A composite material can be used for the substrate 710.

[0441] Also, a single layer material or a multi-layer laminated material can be used for the substrate 710. For example, a material that is laminated with a base material and an insulating film that prevents the diffusion of impurities contained in the base material is called a substrate. It can be used for the plate 710. Specifically, the diffusion of impurities contained in the glass a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or the like; A material in which multiple films are laminated can be used for the substrate 710. Alternatively, a resin and a resin can be laminated. Silicon oxide film, silicon nitride film, or silicon oxynitride film that prevents the diffusion of penetrating impurities A material in which the above-mentioned layers are laminated can be used for the substrate 710.

[0442] Specifically, polyester, polyolefin, polyamide, polyimide, polycarbonate A resin film such as acrylic resin, a resin plate, or a laminate is used as the substrate 710. It is possible.

[0443] Specifically, polyester, polyolefin, polyamide (nylon, aramid, etc.), Polyimide, polycarbonate, polyurethane, acrylic resin, epoxy resin or silicone Materials including resins with fluorocarbon bonds can be used for the substrate 710 .

[0444] Specifically, polyethylene terephthalate (PET), polyethylene naphthalate (P EN), polyethersulfone (PES), acrylic, etc. may be used for the substrate 710. can be done.

[0445] Alternatively, the substrate 710 may be made of paper or wood.

[0446] For example, a flexible substrate can be used for the substrate 710 .

[0447] Note that a method of directly forming a transistor or a capacitor on a flexible substrate is used. In addition, a transistor or a capacitor element can be formed on a heat-resistant substrate for a process. and a method for transposing a transistor, a capacitor, or the like formed on a flexible substrate. can be used.

[0448] <<Board 770>> The substrate 770 can be made of a light-transmitting material.

[0449] For example, the materials that can be used for substrate 710 can be used for substrate 770 .

[0450] "Sealant 730" The sealant 730 may be made of an inorganic material, an organic material, or a composite material of an inorganic material and an organic material. This can be done.

[0451] For example, an organic material such as a heat-melting resin or a hardening resin is used for the sealant 730. It is possible.

[0452] For example, reactive curing adhesives, light curing adhesives, heat curing adhesives or / and anaerobic adhesives. The sealant 730 can be an organic material such as an adhesive.

[0453] Specifically, epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide Mido resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyrate) Adhesives containing EVA (ethylene vinyl acetate) resin, etc. are used as sealing materials. It can be used for.

[0454] Optical Film 770P The substrate 770 is sandwiched between the optical film and the liquid crystal layer 753. The optical film 770P is It has an area that overlaps with the first display element 750EB.

[0455] For example, a polarizing plate, a retardation plate, a diffusion film, a light-collecting film, etc. are used as the optical film 770 It can be used for P.

[0456] Furthermore, a hard coat layer that prevents scratches can be applied to the optical film.

[0457] Second display unit 500E The second display unit 500E includes a pixel unit, a wiring unit, a source driver circuit unit SD2, a gate driver The inverter circuit portion GD2 or the terminal portion (see FIG. 38 and FIG. 42).

[0458] The second display unit 500E includes a substrate 510, an insulating film 570, a structure KB2, or a bonding layer. It has 530.

[0459] In addition, a colored film or insulating film 571 is provided.

[0460] Also, the insulating film 521A, the insulating film 521B, the partition wall 528A, or the insulating film 528B is provided. .

[0461] The insulating film 570 has an area that overlaps with the substrate 510 .

[0462] The bonding layer 530 has a function of bonding the substrate 510 and the insulating film 570 together.

[0463] The structure KB2 is disposed between the substrate 510 and the insulating film 570. The structure KB2 is It has a function of forming a gap of a predetermined distance between the substrate 510 and the insulating film 570 .

[0464] 《Pixel section》 The pixel section includes pixels.

[0465] For example, a pixel may have a plurality of sub-pixels. A pixel that displays green, a sub-pixel that displays red, etc. can be used. A sub-pixel that displays white or a sub-pixel that displays yellow can be used.

[0466] For example, if the area of ​​the pixel that displays blue is made larger than the area of ​​the pixel that displays other colors, This makes it possible to display white in a suitable manner.

[0467] 《Pixels》 The pixel includes a second display element 550EB, a colored film CFB2, and a pixel circuit.

[0468] Second display element 550EB The second display element 550EB has a region overlapping with the opening 751H and a region facing the opening 751H. It has the function of emitting light.

[0469] The second display element 550EB has a light-emitting region that is shaped to overlap the opening 751H. Prepare for the area (see Figure 39).

[0470] Various light-emitting elements can be used for the second display element 550EB. Electroluminescent element, inorganic electroluminescent element or light-emitting diode A glass substrate or the like can be used for the second display element 550EB.

[0471] For example, a third conductive film 551EB and a fourth conductive film having an area overlapping the third conductive film 552, and a light-emitting film disposed between the third conductive film 551EB and the fourth conductive film 552. The layer 553E containing an organic compound can be used for the second display element 550EB ( See Figure 42).

[0472] For example, a laminated body that is laminated so as to emit white light may be formed by adding a layer containing a light-emitting organic compound. Specifically, a luminescent material containing a fluorescent material that emits blue light can be used. and a layer containing an organic compound other than a fluorescent material that emits green or / and red light. and a layer containing a light-emitting organic compound, and a laminated body obtained by laminating these can be used as the layer 553E containing a light-emitting organic compound. Cut.

[0473] For example, the material used for the wiring portion may be used for the third conductive film 551EB or the fourth conductive film 552. You can be there.

[0474] For example, a material that is reflective to visible light and conductive is used for the third conductive film 551. It can be used for EB.

[0475] For example, a material that transmits visible light and has conductivity is used for the fourth conductive film 552. It can be used for.

[0476] Specifically, conductive oxides or conductive oxides containing indium, indium oxide, indium Indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide doped with gallium, etc. can be used for the fourth conductive film 552.

[0477] Alternatively, the fourth conductive film 552 can be formed using a metal film that is thin enough to transmit light.

[0478] "Second colored film" The second colored film is formed on the opening 751H of the first conductive film 751EB and the second display element 550. It is disposed between the EBs.

[0479] The second colored film has an area overlapping the opening 751H and the second display element 550EB. For example, the colored film CFB1 has a function of transmitting light of a predetermined color. The colored film CFB2 can be made of a material having a color similar to that of the colored film CFB2. A part of the light emitted by B is transmitted through the colored film CFB2, the opening 751H, and the colored film CFB1. Then, it can be taken out to the outside of the display device.

[0480] For example, the material that can be used for the colored film CFB1 can be used for the colored film CFB2. Cut.

[0481] 《Pixel circuit》 The transistor ME3 and the like can be used in the pixel circuit.

[0482] For example, the same structure that can be used for the transistor ME1 can be used for the transistor ME3. It is possible.

[0483] For example, the transistor described in the first embodiment or the sixth embodiment may be a transistor ME It can be used for 3.

[0484] <Insulating film> An insulating film 571 is provided between the colored film CFB2 and the bonding layer 530.

[0485] The insulating film 521B has a region overlapping with the conductive film 504 and a region overlapping with the semiconductor film.

[0486] The insulating film 521A is disposed between the semiconductor film and the insulating film 521B (see FIG. 42).

[0487] Insulating film 528B The insulating film 528B flattens steps resulting from various structures that overlap the insulating film 528B. It is possible.

[0488] For example, the material that can be used for the insulating film 728 can be used for the insulating film 528B. do.

[0489] 《Bulkhead 528A》 The partition 528A has an opening in the area overlapping with the second display element 550EB. A material having a specific property can be used for the partition wall 528A. 50EB can be separated from other adjacent structures. The shape of the opening can be used to determine the shape of the second display element.

[0490] For example, the material that can be used for the insulating film 528B can be used for the partition wall 528A. do.

[0491] <<Source driver circuit section SD2>> For example, an integrated circuit can be used for the source driver circuit section SD2. An integrated circuit formed on a silicon substrate can be used (see FIG. 38).

[0492] For example, a COG (Chip on Glass) method is used to form a The source driver circuit section SD2 can be mounted on the pad. Specifically, An integrated circuit can be mounted on the pad, which is electrically connected to the pixel circuit.

[0493] <Gate driver circuit GD2> For example, the transistor ME4 can be used in the gate driver circuit section GD2 (FIG. 4 See 2).

[0494] For example, the transistor described in the first embodiment or the sixth embodiment may be a transistor ME It can be used for 4.

[0495] For example, a semiconductor film that can be formed in the same process as the semiconductor film of the transistor ME3. The conductive film can be used for transistor ME4.

[0496] The same configuration as that of the transistor ME3 can be used for the transistor ME4. Also, a different configuration can be used for transistor ME4.

[0497] <Conductive film 520> The conductive film 520 has a region overlapping with the semiconductor film. 0 and the conductive film 504. This allows the transistor ME3 or the transistor This can improve the reliability of StaME4.

[0498] The conductive film 520 can be used as the second gate electrode of the transistor ME4. 520 can also be referred to as a part of transistor ME3 or transistor ME4.

[0499] For example, the conductive film 520 is electrically connected to a wiring that can supply the same potential as the conductive film 504. can be connected to.

[0500] For example, the material used for the wiring portion can be used for the conductive film 520. conductive oxides or conductive oxides containing indium, indium oxide, indium tin oxide, Indium zinc oxide, indium zinc gallium oxide, zinc oxide, gallium doped The conductive film 520 can be made of zinc oxide or the like.

[0501] 《Wiring section, terminal section》 The wiring portion includes a signal line, and the terminal portion includes a connection electrode 519 (see FIG. 42).

[0502] The signal line is electrically connected to the connection electrode 519. It can be used for 9.

[0503] The connection electrode 519 is formed on the flexible printed circuit board FP using, for example, a conductive member ACF2. Electrically connected to C2.

[0504] The material that can be used for the signal line 711 or the connection electrode 719 is It can be used for pole 519.

[0505] Conductive material ACF2 The materials that can be used for the conductive member ACF1 can be used for the conductive member ACF2. .

[0506] <<Board 510>> A material having heat resistance enough to withstand heat treatment during the manufacturing process can be used for the substrate 510. Cut.

[0507] For example, a laminated material of a base material 510A and an insulating film 510B is used for the substrate 510. 0B has the function of suppressing the diffusion of impurities contained in the base material 510A or impurities from the outside. Prepare.

[0508] For example, the materials that can be used for the substrate 710 can be used for the substrate 510. The substrate 510 may also be made of a material that has a light-blocking property.

[0509] "Insulating Film 570" For example, the insulating film 570 can be formed using a single layer material or a stack of multiple layers. For example, a material on which an insulating film that prevents impurity diffusion is laminated can be used for the insulating film 570. Specifically, a silicon oxide layer that prevents the diffusion of impurities that penetrate the resin and the like can be formed. One or more films selected from a silicon nitride layer, a silicon oxynitride layer, etc. are laminated. The insulating film 570 can be made of any of the above materials.

[0510] 《Joining layer 530》 The bonding layer 530 may be made of an inorganic material, an organic material, or a composite material of an inorganic material and an organic material. can be done.

[0511] For example, the material that can be used for the sealing material 730 can be used for the bonding layer 530. do.

[0512] 《Adhesive layer 535》 The adhesive layer 535 may be made of an inorganic material, an organic material, or a composite material of an inorganic material and an organic material. can be done.

[0513] For example, the materials that can be used for the bonding layer 530 can be used for the adhesive layer 535. .

[0514] <Display device configuration example 2.> Other structures of the display device according to one embodiment of the present invention are shown in FIGS. 38, 39, and 43 to 4. This will be explained with reference to 5.

[0515] FIG. 43 shows the cross-sectional view of the present invention taken along the cutting lines Z1-Z2, Z3-Z4, and Z5-Z6 shown in FIG. FIG. 1 is a cross-sectional view illustrating a cross-sectional configuration of a display device according to one embodiment.

[0516] FIG. 44(A) shows the main part along the cutting lines Z1-Z2, Z3-Z4, and Z5-Z6 shown in FIG. FIG. 10 is a cross-sectional view illustrating a cross-sectional structure of a first display portion 700F of a display device according to one embodiment of the invention; FIG. 44B is a cross-sectional view illustrating the structure of a transistor.

[0517] FIG. 45 shows the cross-sectional view of the present invention taken along the cutting lines Z1-Z2, Z3-Z4, and Z5-Z6 shown in FIG. 10 is a cross-sectional view illustrating a cross-sectional configuration of a second display unit 500F of the display device according to one embodiment. FIG.

[0518] Here, the configurations different from the display device described above will be described in detail, and the same configurations will be described. The above description applies to the parts that can be used.

[0519] First display unit 700F The first display unit 700F includes a flat first conductive film 751FB, and an optical filter. The structure KB1 is provided on the substrate 770, and the top gate 41, the gate-type transistors MF1 and MF2 are provided. However, it differs from the first display unit 700E to be described.

[0520] For example, a polarizer containing a dichroic dye can be used in the optical film 770PF.

[0521] Second display unit 500F In the second display section 500F, the colored film CFB2 is not provided, and the colored film CFB2 is not provided. The second display element 550FB is provided to emit light of a color, etc., and the top-gate transistor The second embodiment will be described with reference to FIG. It is different from display unit 500E.

[0522] A second display element 550 that emits a different color than the second display elements disposed in other sub-pixels. For example, the second display element 550FB that emits blue light is used as a sub-pixel. a second display element that emits green or red light to one sub-pixel and a second display element that emits green or red light to the other sub-pixel; .

[0523] Specifically, the second layer 553F includes a layer 553F containing a light-emitting organic compound that emits blue light. The display element is used in one subpixel. The display element includes a light-emitting organic compound that emits green light. a second display element including a layer containing a light-emitting organic compound that emits red light or a layer containing a light-emitting organic compound that emits red light, Used for sub-pixels.

[0524] The layer containing the light-emitting organic compound may be formed by evaporation using a shadow mask or Alternatively, an ink jet method can be used. This allows the second sub-pixels arranged in other sub-pixels to be printed. A second display element 550FB that emits a different color from the first display element is used for one subpixel. This can be done.

[0525] Transistor MF1 The transistor MF1 has a conductive film 704 having a region overlapping with the insulating film 710B, and an insulating film 7 10B and a semiconductor film 718 having a region disposed between the conductive film 704. The conductive film 704 functions as a gate electrode (FIG. 44B).

[0526] The semiconductor film 718 is divided into a first region 718A that does not overlap with the conductive film 704 and a second region 718B. 18B and the second region 718B overlapping the conductive film 704 between the first region 718A and the second region 718B. 3 area 718C.

[0527] The transistor MF1 has an insulating film 706 between the third region 718C and the conductive film 704. The insulating film 706 functions as a gate insulating film.

[0528] The first region 718A and the second region 718B have a lower resistance than the third region 718C. and has the function of a source region or a drain region.

[0529] For example, the method for controlling the resistivity of an oxide semiconductor film, which will be described later, can be applied to the first This can be used in the method for forming the region 718A and the second region 718B. For example, plasma treatment using a gas containing a rare gas can be applied to the conductive film 7. When 04 is used as a mask, part of the shape of the third region 718C is changed to the shape of the end of the conductive film 704. and self-alignment can be achieved.

[0530] The transistor MF1 includes a conductive film 712A in contact with the first region 718A and a conductive film 712B in contact with the second region 718B. and a conductive film 712B in contact with the conductive film 18B. It functions as a source electrode or a drain electrode.

[0531] A transistor that can be formed in the same process as transistor MF1 is used for transistor MF2. You can be there.

[0532] <Method for controlling resistivity of oxide semiconductor film> A method for controlling the resistivity of an oxide semiconductor film will be described.

[0533] The oxide semiconductor film having a predetermined resistivity is formed on the conductive film 720, the first region 718A, or the second region 718B. The resistivity of the oxide semiconductor film can be controlled by the following method. The method for controlling the resistivity of the second oxide semiconductor film 111 described in Embodiment 1 can be referred to.

[0534] Note that the oxide film has a higher hydrogen concentration and / or oxygen vacancy than the semiconductor film 718 and a lower resistivity. A compound semiconductor film is used for the conductive film 720.

[0535] The hydrogen concentration in the conductive film 720 is twice that in the semiconductor film 718. or more, preferably 10 times or more.

[0536] The resistivity of the conductive film 720 is 1×10 -8 more than 1×1 0 -1 It is less than double.

[0537] Specifically, the resistivity of the conductive film 720 is 1×10 -3 Ωcm or more 1×10 4 Less than Ωcm , preferably 1 x 10 -3 Ωcm or more 1×10 -1 It is less than Ωcm.

[0538] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do.

[0539] (Embodiment 8) In this embodiment, electronic devices including the liquid crystal display device of one embodiment of the present invention will be described with reference to FIGS. The explanation will be given with reference to FIG.

[0540] The display module 8000 shown in FIG. 46 includes an upper cover 8001 and a lower cover 8002. Between them, touch panel 8004 connected to FPC8003 and A display panel 8006, a frame 8009, a printed circuit board 8010, and a battery 8011 are mounted on the display panel 8006. Has.

[0541] The display device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0542] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel The shape and dimensions can be changed as needed to fit the size of the 8006.

[0543] The touch panel 8004 is a resistive or capacitive touch panel. The display panel 8006 can be used by overlapping it with the opposing substrate (sealing substrate). 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 006 to make it an optical touch panel.

[0544] The frame 8009 has a function of protecting the display panel 8006 and also a function of preventing the movement of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the operation of the The frame 8009 may also function as a heat sink.

[0545] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. This can be omitted if a commercial power source is used.

[0546] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0547] 47(A) to 47(H) are diagrams showing electronic devices. These electronic devices are housed in a housing. Body 5000, display unit 5001, speaker 5003, LED lamp 5004, operation key 50 05 (including a power switch or an operation switch), a connection terminal 5006, a sensor 5007 ( Force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances , sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, 5008, a microphone 5009, etc. can.

[0548] FIG. 47(A) shows a mobile computer, which includes, in addition to the above, a switch 5009 , an infrared port 5010, etc. FIG. 47(B) shows a portable terminal equipped with a recording medium. A portable image reproducing device (for example, a DVD reproducing device) is also included. It can have a display unit 5002, a recording medium reading unit 5011, etc. It is a group-type display, and in addition to the above, it has a second display unit 5002, a support unit 5012 , earphones 5013, etc. FIG. 47(D) shows a portable gaming machine. In addition to the above, it may have a recording medium reading unit 5011, etc. It is a digital camera with a TV receiving function, and in addition to the above, it also has an antenna 5014, The mobile phone may have a shutter button 5015, an image receiving unit 5016, etc. It is a belt-type gaming machine, and in addition to the above, it has a second display unit 5002, a recording medium reading unit 5011, , etc. FIG. 47(G) shows a portable television receiver, which can be used with the above-mentioned In addition, it may have a charger 5017 capable of transmitting and receiving signals. ) is a wristwatch type information terminal, and in addition to the above, it also includes a band 5018, a clasp 5019 The display unit 5001 mounted on the housing 5000, which also serves as a bezel, is non-rectangular. The display unit 5001 has an icon 5305 that indicates the time, other Icon 5306 and the like can be displayed.

[0549] The electronic devices shown in FIGS. 47(A) to 47(H) can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Panel function, calendar, date or time display function, various software ( It has a function to control processing by a program, a wireless communication function, and various controls using the wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, The function of receiving, reading out the program or data recorded on the recording medium and displaying it on the display Furthermore, in an electronic device having multiple display units, In this case, one display section is used mainly to display image information, and another display section is used mainly to display text information. or a function to display images that take parallax into account on multiple displays to create a three-dimensional image. Furthermore, in electronic devices having an image receiving unit, The camera has the functions of taking still images, taking videos, and automatically or manually correcting the images. function to save the captured images to a recording medium (external or built-in to the camera); It is possible to have a function to display an image on the display unit. The functions that the electronic device shown in H) can have are not limited to these, and it may have various functions. It is possible.

[0550] The electronic device of this embodiment is characterized by having a display unit for displaying some information. The liquid crystal display device of one embodiment of the present invention can be used for the display portion.

[0551] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done. [Example]

[0552] In this example, a liquid crystal display device according to one embodiment of the present invention was manufactured, and display confirmation was performed. The cross-sectional structure of the pixels 70R and 70G of the liquid crystal display device corresponds to that shown in FIG. The cross-sectional structure of element 70B corresponds to FIG.

[0553] First, Table 1 shows the specifications of the liquid crystal display device fabricated in this example.

[0554] [Table 1]

[0555] The liquid crystal display device manufactured in this example is an active matrix reflective liquid crystal display device, a color The FET on the backplane side is CAAC-IGZO. The reflectance of the manufactured liquid crystal display device was 25.1%, and the NTSC ratio was 37%.

[0556] A display example of the liquid crystal display device is shown in FIG. 48. As shown in FIG. 48, the liquid crystal display device of one embodiment of the present invention can provide a high contrast display while maintaining a high aperture ratio.

[0557] The structure shown in this embodiment can be used in appropriate combination with structures shown in other embodiment modes. Cut. [Explanation of symbols]

[0558] 50 transistors 50B transistor 50G transistor 50R transistor 51 Liquid crystal element 51B Liquid crystal element 55 Capacitor element 70 pixels 70B pixels 70G pixels 70R pixels 71 Pixel section 74 Scanning line driving circuit 75 Capacitance wiring 76 Signal line driver circuit 77 scan lines 79 Signal Line 79B signal line 79G signal line 79R signal line 80 LCD display device 102 Circuit Board 104 gate electrode 106 insulating film 107 Insulating film 108 insulating film 110 Oxide semiconductor film 110a Oxide semiconductor film 111 Oxide semiconductor film 111a Oxide semiconductor film 112a Source electrode 112b Drain electrode 114 insulating film 116 Insulating film 118 insulating film 119 Insulating Film 120 Conductive film 120a Conductive film 120b Conductive film 121 Conductive film 122 Conductive film 130 insulating film 141 Aperture 142 Aperture 143 Aperture 150 transistors 151 transistors 160 Capacitor 170 Colored film 171 Colored film 193 Target 194 Plasma 202 Substrate 204 Conductive film 206 Insulating film 207 Insulating Film 208 Oxide semiconductor film 208a Oxide semiconductor film 208b Oxide semiconductor film 208c Oxide semiconductor film 211a Oxide semiconductor film 211b Oxide semiconductor film 212a Conductive film 212b Conductive film 214 insulating film 216 Insulating film 218 Insulating film 219 Insulating Film 220b Conductive film 252a opening 252b opening 252c opening 270 transistors 270A transistor 270B transistor 302 Substrate 303 Substrate 311a Oxide semiconductor film 311B Oxide semiconductor film 311G Oxide semiconductor film 311R Oxide semiconductor film 314 Insulating film 316 Insulating Film 318 Insulating Film 319 Insulating Film 320B Pixel electrode 320G pixel electrode 320R pixel electrode 325B Conductive film 325G conductive film 325R conductive film 330 Insulating Film 330a insulating film 330b insulating film 330B insulating film 330G insulating film 330R insulating film 333 Structure 335 Orientation Film 336 Alignment Film 337 Overcoat film 340B Colored film 340G colored film 340R colored film 341 Liquid Crystal Layer 344 Insulating Film 345 Common electrode 500E display 500F display section 504 Conductive film 510 board 510A base material 510B insulating film 519 Connecting electrode 520 Conductive film 521A Insulating film 521B insulating film 528A Bulkhead 528B insulating film 530 Bonding layer 535 Adhesive layer 550EB display element 550FB display element 551EB Conductive film 552 Conductive film 553E layer 553F layer 570 insulating film 571 Insulating Film 700E display 700F display section 702E pixels 702EB subpixels 702EG subpixel 702ER subpixel 704 Conductive film 706 Insulating film 710 board 710A base material 710B insulating film 711 Signal Line 712A Conductive film 712B Conductive film 718 Semiconductor Film 718A area 718B area 718C area 719 Connecting electrode 720 Conductive film 721A Insulating film 721B insulating film 728 Insulating Film 730 Sealing material 750EB display element 751EB Conductive film 751EG conductive film 751ER conductive film 751FB conductive film 751H opening 752 Conductive film 753 Liquid crystal layer 770 PCB 770P optical film 770PF Optical Film 771 Insulating Film 777 insulating film 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared port 5011 Recording medium reading unit 5012 Support part 5013 Earphones 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 5018 Band 5019 Clasp 5100 pellets 5120 board 5161 area 5200 pellets 5201 AEON 5202 Lateral growth part 5203 particles 5220 board 5230 Target 5240 Plasma 5260 Heating mechanism 5305 Icon 5306 Icons 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

[Claim 1] a first pixel electrode; a second pixel electrode; a transistor electrically connected to the first pixel electrode; a capacitance element electrically connected to the transistor; a first insulating film, a second insulating film, and a third insulating film; The transistor is a gate electrode; a gate insulating film provided in contact with the gate electrode; a first oxide semiconductor film provided in contact with the gate insulating film and overlapping with the gate electrode; a source electrode and a drain electrode electrically connected to the first oxide semiconductor film, one of a pair of electrodes of the capacitor includes a second oxide semiconductor film; the first insulating film is provided on the first oxide semiconductor film; the second insulating film is provided on the second oxide semiconductor film such that the second oxide semiconductor film is sandwiched between the first insulating film and the second insulating film; the third insulating film is provided over an end portion of the first pixel electrode, The second pixel electrode is provided on the third insulating film.

Images