Semiconductor Devices

Abstract

To provide a display device and a semiconductor device, having transistors in a pixel region and a drive circuit region and configured to suppress changes in electric characteristics and improve reliability.SOLUTION: A display device includes a first substrate 102 adjacent to the outside of a pixel region 142, the first substrate including a drive circuit region including at least one second transistor 103 configured to supply a signal to a first transistor 101 included in each of the pixels in the pixel region, a second substrate 152 provided to face the first substrate, and a first interlayer insulation film 114 having a liquid crystal layer 162 sandwiched between a second substrate and the first substrate and formed of an inorganic insulation material on the first transistor and the second transistor, a second interlayer insulation film 116 formed of an organic insulation material on the fist interlayer insulation film, and a third interlayer insulation film 120 formed of an inorganic insulation material on the second interlayer insulation film. The third interlayer insulation film is provided on a portion of the pixel region. An edge part of the third interlayer insulation film is formed inside the drive circuit region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a display device using a liquid crystal panel or a display device using an organic EL panel. and an electronic device having the display device. [Background technology]

[0002] In recent years, the development of display devices using liquid crystal panels and organic EL panels has become popular. This display device mainly consists of transistors for controlling pixels (pixel transistors). On the other hand, the pixel transistors and the scanning circuit (drive circuit) are formed on the substrate and the peripheral ICs are used. Both are classified as having the scanning circuit formed on the same substrate.

[0003] In order to narrow the frame of the display device or reduce the cost of peripheral ICs, the display device with integrated driver circuit However, as a transistor to be used in a driving circuit, a pixel transistor The electrical properties (e.g., field-effect mobility (μFE) or threshold voltage) used for the transistor Furthermore, high electrical properties are required.

[0004] Silicon-based semiconductor materials are widely known as semiconductor thin films that can be used in transistors. However, oxide semiconductors are attracting attention as other materials. As a semiconductor thin film, the electron carrier concentration is 10 18 / cm 3 Less than Indium (In) A transistor using an amorphous oxide containing gallium (Ga) and zinc (Zn) is disclosed. (See, for example, Patent Document 1).

[0005] A transistor using an oxide semiconductor for the semiconductor layer is made of amorphous silicon-based semiconductor material. Because the field-effect mobility is higher than that of transistors that use silicon as the semiconductor layer, the operating speed This is suitable for a display device with an integrated driving circuit, and polycrystalline silicon is used for the semiconductor layer. The manufacturing process is easier than that of conventional transistors.

[0006] However, in a transistor using an oxide semiconductor for a semiconductor layer, hydrogen and moisture are added to the oxide semiconductor. When impurities such as ions enter the transistor, carriers are formed, and the electrical characteristics of the transistor change. There is a problem with movement.

[0007] In order to solve the above-mentioned problems, the oxide used as the channel formation region of the transistor is The concentration of hydrogen atoms in the semiconductor film is 1×10 16 cm -3 By reducing the A transistor having such a structure has been disclosed (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-165528 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-139047 Summary of the Invention [Problem to be solved by the invention]

[0009] As described in Patent Document 2, a transistor using an oxide semiconductor film as a semiconductor layer In order to sufficiently maintain the electrical characteristics of the capacitor, hydrogen, moisture, etc. must be removed from the oxide semiconductor film. It is important to eliminate the force.

[0010] In addition, when transistors are used in both the pixel region and the driver circuit region of a display device, Although it depends on the method, the transistors used in the driver circuit area are electrically Because the load is large, the electrical characteristics of the transistor used in the driver circuit region are important.

[0011] In particular, a transistor using an oxide semiconductor film as a semiconductor layer is used in a pixel region and a driver circuit region. In the display device used in the driving circuit area, in a reliability test under a high temperature and high humidity environment, Deterioration of transistors has become a problem. The causes of this deterioration include: Moisture and other substances may penetrate from the organic insulating film formed on the substrate into the oxide semiconductor film used in the semiconductor layer. This is because the carrier density of the oxide semiconductor film increases.

[0012] In view of the above, one embodiment of the present invention is a display device including transistors in a pixel region and a driver circuit region. One of the objectives of the present invention is to suppress fluctuations in electrical characteristics and improve reliability in a semiconductor device. In particular, in a display device in which an oxide semiconductor film is used in a channel formation region of a transistor, This can prevent hydrogen and moisture from entering the oxide semiconductor film, thereby suppressing fluctuations in electrical characteristics. In both cases, improving reliability is one of the challenges. [Means for solving the problem]

[0013] In view of the above-described problems, in one embodiment of the present invention, a transistor used in a pixel region and a driver circuit region is In a display device having a transistor, fluctuations in the electrical characteristics of the transistor can be suppressed. More specifically, a structure in which an oxide semiconductor film is formed in a channel formation region of a transistor is provided. The planarization film is formed of an organic insulating material on the transistor. The oxide semiconductor film, particularly the oxide semiconductor film used in the driver circuit region, is characterized in that hydrogen and moisture are not easily absorbed. The structure will be such that it is difficult for the worm to get into the hole. More specifically, the structure is as follows:

[0014] One aspect of the present invention is a pixel electrode and at least one second pixel electrically connected to the pixel electrode. A pixel region in which multiple pixels including transistor 1 are arranged and an adjacent pixel region outside the pixel region and at least one transistor that supplies a signal to a first transistor included in each pixel of the pixel region. a first substrate on which a driving circuit region including the second transistor is formed; a second substrate disposed opposite the first substrate and a liquid crystal layer sandwiched between the first substrate and the second substrate; and a second transistor formed of an inorganic insulating material on the first transistor and the second transistor. a first interlayer insulating film; and a second interlayer insulating film formed on the first interlayer insulating film by using an organic insulating material. and a third interlayer insulating film formed on the second interlayer insulating film using an inorganic insulating material, The third interlayer insulating film is provided on a part of the pixel region, and an end of the third interlayer insulating film is disposed on the driving circuit region. The display device is characterized in that it is formed inside the area.

[0015] In the above configuration, a first alignment film is provided on the pixel electrode, and a second alignment film is formed on the first alignment film. a liquid crystal layer provided on the liquid crystal layer, a second alignment film provided on the liquid crystal layer, and an opposing electrode provided on the second alignment film. an organic protective insulating film provided on the counter electrode; and a colored insulating film provided on the organic protective insulating film. The colored film may have a light-shielding film and a light-shielding film, and a second substrate provided on the colored film and the light-shielding film.

[0016] Another aspect of the present invention is a pixel electrode and at least one a pixel region in which a plurality of pixels including another first transistor are arranged; A small number of transistors are provided adjacent to the outside of the pixel region and supply signals to the first transistors included in each pixel of the pixel region. a first substrate on which a driving circuit region including at least one second transistor is formed; a second substrate disposed opposite to the first substrate, and a substrate sandwiched between the first substrate and the second substrate; a light-emitting layer formed of an inorganic insulating material on the first transistor and the second transistor; a first interlayer insulating film formed thereon, and a second interlayer insulating film formed thereon using an organic insulating material; an interlayer insulating film and a third interlayer insulating film formed on the second interlayer insulating film using an inorganic insulating material; The third interlayer insulating film is provided on a part of the pixel region, and an end of the third interlayer insulating film is The display device is characterized in that it is formed inside the driving circuit region.

[0017] In the above configuration, a light-emitting layer provided on the pixel electrode, an electrode provided on the light-emitting layer, may have

[0018] In each of the above structures, the third interlayer insulating film is a silicon nitride film or a silicon nitride oxide film. It is preferable that the film is one selected from the group consisting of a silicon dioxide film and an aluminum oxide film.

[0019] In each of the above configurations, the first transistor and the second transistor have a channel The semiconductor material forming the formation region is preferably an oxide semiconductor. The first transistor and the second transistor have a gate electrode and an oxide semiconductor formed on the gate electrode. and a source electrode and a drain electrode formed on the semiconductor layer. It is preferable that the configuration be as follows.

[0020] One embodiment of the present invention also includes in its category an electronic device having a display device having any of the above structures. is. [Effects of the Invention]

[0021] Fluctuations in electrical characteristics in a display device having transistors in a pixel region and a driver circuit region In particular, the channel of the transistor can be prevented from being damaged and the reliability can be improved. In a display device using an oxide semiconductor film in a formation region, hydrogen or moisture This suppresses the intrusion of foreign matters, suppresses fluctuations in electrical characteristics, and improves reliability. do. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are diagrams illustrating a top surface of one embodiment of a display device. [Figure 2] 1A and 1B are cross-sectional views illustrating one embodiment of a display device. [Figure 3] 1A and 1B are diagrams illustrating a top surface of one embodiment of a display device. [Figure 4] 1A and 1B are cross-sectional views illustrating one embodiment of a display device. [Figure 5] 1A and 1B are a circuit diagram and a cross-sectional view illustrating an example of a display device with an image sensor according to one embodiment of the present invention. [Figure 6] FIG. 10 illustrates an example of a tablet terminal according to one embodiment of the present invention. [Figure 7] 1A to 1C illustrate examples of electronic devices according to one embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing the ion intensity of emitted gas at each mass-to-charge ratio. [Figure 9] FIG. 10 is a graph showing the ion intensity at each mass-to-charge ratio relative to the substrate surface temperature. [Figure 10] Cross-sectional observation image of the sample. [Figure 11] FIG. 10 is a graph showing the electrical characteristics of each sample. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and it is understood by those skilled in the art that various modifications may be made to the modes and details thereof. The present invention will be easily understood by reading the following description of the embodiments. It is not something that is done.

[0024] In the embodiments described below, the same reference numerals are used in common between different drawings. It should be noted that the thicknesses and widths of the components, i.e., layers and regions, and their relative positions are not necessarily the same as those of the components shown in the drawings. In the description of the embodiments, the relationships are exaggerated for clarity.

[0025] In addition, the terms "electrode" and "wiring" used in this specification and the like refer to these components functionally. This is not a limitation. For example, an "electrode" may be used as part of a "wiring." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably with "electrodes" and "wiring." This also includes cases where the wiring is formed integrally.

[0026] In this specification and the like, a silicon nitride oxide film refers to a film containing nitrogen, oxygen, silicon, and The film contains as a component, and the nitrogen content is higher than the oxygen content. The silicon nitride film contains oxygen, nitrogen, and silicon as components, and The film has a higher content of Cr than the content of nitrogen.

[0027] Also, the functions of "source" and "drain" can be changed by using transistors with different polarities. Or, when the direction of the current changes during circuit operation, the positions may be swapped. Therefore, in this specification and the like, the terms "source" and "drain" are used interchangeably. It is assumed that this is possible.

[0028] (Embodiment 1) In this embodiment, a display device using a liquid crystal panel is illustrated as one mode of the display device. 1 and 2.

[0029] 1A, 1B, and 1C are top views of a display device as one mode of the display device. 1A shows the entire display device, and FIG. 1B shows a part of the drive circuit unit of the display device. FIG. 1(C) shows a top view of a part of the pixel region. This corresponds to the cross-sectional view taken along line X1-Y1 in FIG.

[0030] In the display device shown in FIG. 1A, a pixel region 142 provided on a first substrate 102 and a driving circuit region adjacent to the outside of the pixel region 142 and supplying signals to the pixel region 142. The shield surrounds a gate driver circuit section 140 and a source driver circuit section 144. A sealing material 166 is provided and the pixel region 1 is sealed by the second substrate 152. 42, and a first substrate 43 in which a gate driver circuit unit 140 and a source driver circuit unit 144 are provided. The second substrate 152 is provided so as to face the first substrate 102. 2, the gate driver circuit section 140, and the source driver circuit section 144 are mounted on the first substrate 1. The display element is sealed by the O2, the sealant 166, and the second substrate 152.

[0031] In FIG. 1A, the first substrate 102 is surrounded by a sealing material 166. The pixel region 142, the gate driver circuit section 140, the source driver circuit section 141, and the like are arranged in a region different from the region where the pixel region 142 is arranged. The FPC terminal portion 146 (FPC: Flexib) is electrically connected to the driver circuit portion 144. The FPC terminal portion 146 is provided with a printed circuit. The FPC 148 is connected to the pixel area 142, the gate driver circuit section 140, and the source driver circuit section 142. Various signals and potentials are supplied to the driver circuit section 144 via an FPC 148. There are.

[0032] In addition, in FIG. 1A, the gate driver circuit section 140 and the source driver circuit section 144 is formed on the same first substrate 102 as the pixel region 142. For example, only the gate driver circuit section 140 may be formed on the first substrate 102. A substrate (for example, a single crystal semiconductor film, A drive circuit board formed of a polycrystalline semiconductor film is mounted on the first substrate 102. is also good.

[0033] In FIG. 1A, the gate driver circuit section 140 is provided on both sides of the pixel region 142. Although the configuration in which two are arranged is illustrated, the present invention is not limited to this configuration. For example, The gate driver circuit section 140 may be arranged on only one side of the gate electrode 142 .

[0034] The method of connecting the separately formed drive circuit board is not particularly limited, and may be any of the following: (Chip On Glass) method, wire bonding method, or TAB (Tap Automated Bonding methods can also be used. The device includes a panel in which a display element is sealed, and an IC including a controller in the panel. This includes modules in which the above are implemented.

[0035] In this way, a part or the whole of the driving circuit including the transistors can be formed in the same region as the pixel region 142. It can be integrally formed on the first substrate 102 to form a system on panel.

[0036] In addition, in FIG. 1C, the first transistor 101 and the capacitor element 102 are provided in the pixel region 142. The first transistor 101 has a gate electrode 107 formed on the semiconductor layer 108. The gate electrode 104, the source electrode 110, and the drain electrode 112 are electrically connected to each other. Although not shown in the plan view of FIG. 1(C), the first transistor On the photoresist 101, a first interlayer insulating film made of an inorganic insulating material is formed. a second interlayer insulating film formed of an organic insulating material on the first interlayer insulating film; and a second interlayer insulating film formed of an inorganic insulating material on the second interlayer insulating film. The third interlayer insulating film is formed. The capacitor element 107 has a capacitor electrode 11 8, a third interlayer insulating film formed on the capacitance electrode 118, and a second interlayer insulating film formed on the third interlayer insulating film. The pixel electrode 122 is formed by connecting the pixel electrodes 122.

[0037] In FIG. 1B, the gate driver circuit section 140, which is the driving circuit area, is provided with the first A second transistor 103 and a third transistor 105 are formed. Each transistor of the gate driver circuit section 140 has a gate electrode 10 with respect to the semiconductor layer 108. 4, a source electrode 110, and a drain electrode 112 are electrically connected to each other. In the gate driver circuit section 140, the gate lines including the gate electrodes 104 are The source line including the source electrode 110 extends in the vertical direction, and the drain electrode 11 The drain line including the source electrode extends in the vertical direction and is spaced apart from the source electrode.

[0038] a gate driver circuit including a second transistor 103 and a third transistor 105; The unit 140 supplies a signal to the first transistor 101 included in each pixel of the pixel region 142. It is possible.

[0039] In addition, the second transistor 103 and the third transistor The transistor 105 requires a relatively high voltage to control various signals and to boost voltages. Specifically, a voltage of about 10 V to 30 V is required. The first transistor 101 in the Therefore, the gate driver circuit section 1 can be driven with a voltage of about several volts to 20 volts. The second transistor 103 and the third transistor 105 in the pixel region 140 are 42, the stress applied to the first transistor 101 is very large. It becomes successful.

[0040] In order to more specifically explain the configuration of the display device shown in FIGS. 1(A), 1(B), and 1(C), Using Figure 2, which corresponds to the cross-sectional view of X1-Y1 in (A), (B), and (C), The configurations of the driver circuit section 140 and the pixel region 142 will be described below.

[0041] In the pixel region 142, the first substrate 102 and the gate electrode formed on the first substrate 102 are a gate electrode 104, a gate insulating film 106 formed on the gate electrode 104, and a gate insulating film a semiconductor layer 108 provided in contact with the gate electrode 106 and overlapping the gate electrode 104; The source electrode 110 and the drain electrode 111 are formed on the insulating film 106 and the semiconductor layer 108. 12 form the first transistor 101.

[0042] In the pixel region 142, on the first transistor 101, more specifically, on the gate insulator An inorganic insulating layer is formed on the insulating film 106, the semiconductor layer 108, the source electrode 110, and the drain electrode 112. A first interlayer insulating film 114 formed of an organic insulating material is provided on the first interlayer insulating film 114. a second interlayer insulating film 116 formed by the above method and a capacitive capacitor formed on the second interlayer insulating film 116; and a second interlayer insulating film 116 and a capacitor electrode 118 formed of an inorganic insulating material on the second interlayer insulating film 116 and the capacitor electrode 118. a third interlayer insulating film 120, a pixel electrode 122 formed on the third interlayer insulating film 120; It has the following characteristics.

[0043] The capacitance electrode 118, the third interlayer insulating film 120, and the pixel electrode 122 form a capacitance. The element 107 is formed. The capacitor electrode 118, the third interlayer insulating film 120, and the pixel electrode 122 are formed from a material that is transparent to visible light, This is preferable because it is possible to ensure a large capacitance without impairing the aperture ratio of the region.

[0044] In addition, a first alignment film 124 is provided on the pixel electrode 122, and a liquid crystal display (LCD) is provided on the first alignment film 124. a liquid crystal layer 162 formed thereon, a second alignment film 164 formed on the liquid crystal layer 162, and a second alignment film 164 and an organic protective insulating film provided on the counter electrode 158. 156, a colored film 153 and a light-shielding film 154 provided on the organic protective insulating film 156, and a colored and a second substrate 152 provided on the film 153 and the light-shielding film 154.

[0045] The pixel electrode 122, the first alignment film 124, the liquid crystal layer 162, and the second alignment film 16 4 and the counter electrode 158 form a liquid crystal element 150 which is a display element.

[0046] In the gate driver circuit section 140, a first substrate 102 and a a gate electrode 104 formed on the gate electrode 104; and a gate insulating film 106 formed on the gate electrode 104. The semiconductor layer 10 is in contact with the gate insulating film 106 and is provided at a position overlapping the gate electrode 104. 8, and a source electrode 110 and a drain electrode 112 formed on the gate insulating film 106 and the semiconductor layer 108. The drain electrode 112 and the second transistor 103 and the third transistor 10 5 is formed.

[0047] In addition, in the gate driver circuit section 140, the second transistor 103 and the third transistor On the transistor 105, more specifically, the gate insulating film 106, the semiconductor layer 108, the source electrode a first interlayer insulating film 114 formed on the electrode 110 and the drain electrode 112; A second interlayer insulating film 116 is formed on the interlayer insulating film 114 .

[0048] That is, the third interlayer insulating film 120 is provided on a part of the pixel region 142, and the third layer The end of the interlayer insulating film 120 is formed inside the gate driver circuit section 140, which is the drive circuit region. It is done.

[0049] By adopting such a configuration, moisture taken in from the outside or the inside of the display device can be prevented. The moisture and gases such as hydrogen generated in the gate driver circuit section 140 are removed from the second interlayer insulating film 116. Therefore, the first transistor 101 and the second transistor Moisture, hydrogen, and other gases are introduced into the third transistor 103 and the third transistor 105. This can suppress the

[0050] The second interlayer insulating film 116 made of an organic insulating material is a film that constitutes the display device. To reduce the unevenness of the transistor, an organic insulating material with high flatness is required. This reduces the unevenness of the transistor, thereby improving the image quality of the display device. However, the organic insulating material is easily decomposed by hydrogen, moisture, or the like when heated. The organic components are released as gas.

[0051] However, when the semiconductor layer 108 is made of, for example, a silicon film made of a silicon-based semiconductor material, In transistors, the above-mentioned hydrogen, moisture, and organic gases are a major problem. However, in one embodiment of the present invention, an oxide semiconductor film is used as the semiconductor layer 108. In order to use the second interlayer insulating film 116 made of an organic insulating material, gas is released to the outside. It is necessary to preferably release the electrons. Note that the end of the third interlayer insulating film 120 is the driving circuit region. The structure formed inside the gate driver circuit section 140 is such that the semiconductor layer 108 is made of an oxide. When the semiconductor layer 108 is formed from a semiconductor film, an excellent effect is obtained. Materials other than oxide semiconductors (e.g., silicon-based semiconductor materials such as amorphous silicon and crystalline silicon) The same effect can be obtained with a transistor made of silicon or the like.

[0052] Also, an inorganic insulating material is formed on the second interlayer insulating film 116 formed of an organic insulating material. In this embodiment, the third interlayer insulating film 120 formed by The third interlayer insulating film 120 made of an inorganic insulating material is used as a conductor. Therefore, hydrogen, moisture, etc. can be prevented from penetrating into the second interlayer insulating film 116.

[0053] However, in the second embodiment, the third interlayer insulating film 120 is used for the gate driver circuit section 140. Formed on the second interlayer insulating film 116 on the transistor 103 and the third transistor 105 Then, the gas released from the organic insulating material used for the second interlayer insulating film 116 is diffused to the outside. The second transistor 103 and the third transistor 105 cannot be connected to each other. Get in.

[0054] The gas released from the organic insulating material is used for the semiconductor layer 108 of the transistor. When the oxide semiconductor is penetrated, it is taken in as an impurity in the oxide semiconductor film, and the semiconductor layer 1 The characteristics of the transistor using 08 will fluctuate.

[0055] However, as shown in FIG. 2, the second transistor used in the gate driver circuit section 140 103, and the third interlayer insulating film 120 on the third transistor 105 are opened; That is, the third interlayer insulating film 120 is provided in a part of the pixel region 142, and the third interlayer insulating film The end of the film 120 is formed inside the gate driver circuit section 140. Therefore, by adopting a structure that allows the gas released from the second interlayer insulating film 116 to be diffused to the outside, This can be done.

[0056] As shown in FIG. 2, in the first transistor 101 used in the pixel region 142, The third interlayer insulating film 120 made of an inorganic insulating material is also formed at the position where the semiconductor layer 108 overlaps. By adopting such a configuration, it is possible to form a thin film formed of an organic insulating material. The gas released from the second interlayer insulating film 116 enters the first transistor 101. can be suppressed.

[0057] Here, other components of the display device shown in FIGS. 1 and 2 will be described in detail below. .

[0058] The first substrate 102 and the second substrate 152 are made of aluminosilicate glass, aluminum, Glass materials such as fluorine borosilicate glass and barium borosilicate glass are used. In this case, the first substrate 102 and the second substrate 152 are 8th generation (2160 mm x 2460 mm) m), 9th generation (2400mm x 2800mm or 2450mm x 3050mm), It is preferable to use mother glass such as 10th generation (2950mm x 3400mm). Mother glass shrinks significantly when the processing temperature is high and the processing time is long. When mass production is carried out using a silicon nitride film, the heat treatment in the manufacturing process is preferably at 600°C or less, and more preferably at 100°C or less. The temperature is preferably 450°C or lower, and more preferably 350°C or lower.

[0059] Note that a base insulating film may be provided between the first substrate 102 and the gate electrode 104. The insulating film may be a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a silicon nitride oxide film. Cr film, gallium oxide film, hafnium oxide film, yttrium oxide film, aluminum oxide film As the base insulating film, a silicon nitride film, a gas oxide film, etc. The film may be a hafnium oxide film, a yttrium oxide film, an aluminum oxide film, or the like. Impurities, typically alkali metals, water, hydrogen, etc., are introduced from the first substrate 102 into the semiconductor layer 10. This can prevent the gas from entering into 8.

[0060] The gate electrode 104 may be made of aluminum, chromium, copper, tantalum, titanium, molybdenum, or the like. a metal element selected from the group consisting of tungsten and tungsten, or an alloy containing the above-mentioned metal element; The metal layer can be formed by using an alloy or the like that combines the above-mentioned metal elements. Alternatively, one or more metal elements selected from the group consisting of ammonium, magnesium, and zirconium may be used. The gate electrode 104 may have a single layer structure or a laminated structure of two or more layers. a single-layer structure of an aluminum film containing titanium; a two-layer structure of an aluminum film with a titanium film laminated on top; Two-layer structure with a titanium film stacked on a titanium nitride film, and a tungsten film stacked on a titanium nitride film A two-layer structure in which a tungsten film is laminated on a tantalum nitride film or a tungsten nitride film. Two-layer structure: titanium film, aluminum film on top of titanium film, and titanium film on top of that. There are also three-layer structures that form an aluminum film. A film of an element selected from the group consisting of tungsten, molybdenum, chromium, neodymium, and scandium, or a combination of these elements A combined alloy film or nitride film may also be used.

[0061] The gate electrode 104 is made of indium tin oxide, indium containing tungsten oxide, or the like. oxide, indium zinc oxide with tungsten oxide, indium oxide with titanium oxide oxide, indium tin oxide containing titanium oxide, indium zinc oxide, silicon oxide A light-transmitting conductive material such as indium tin oxide may also be used. Alternatively, the light-transmitting conductive material and the metal element may be laminated together.

[0062] In addition, an In-Ga-Zn oxynitride is formed between the gate electrode 104 and the gate insulating film 106. Semiconductor film, In-Sn oxynitride semiconductor film, In-Ga oxynitride semiconductor film, In-Zn Sn-based oxynitride semiconductor film, Sn-based oxynitride semiconductor film, In-based oxynitride semiconductor film, metal nitride film ( These films may have a resistance of 5 eV or more, preferably 5.5 eV or more. Since the work function of the oxide semiconductor is larger than the electron affinity of the oxide semiconductor, The threshold voltage of the transistor using the conductor can be shifted to the positive side, For example, an In-Ga-Zn oxynitride semiconductor can be used. When a conductive film is used, the nitrogen concentration is at least higher than that of the semiconductor layer 108, specifically, 7 atomic %. The above-mentioned In-Ga-Zn-based oxynitride semiconductor film is used.

[0063] The gate insulating film 106 may be, for example, a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film. Silicon film, silicon nitride film, aluminum oxide film, hafnium oxide film, gallium oxide film Alternatively, a Ga-Zn-based metal oxide film or the like may be used, and may be provided as a laminated layer or a single layer. In order to improve the interface characteristics with the semiconductor layer 108, at least the gate insulating film 106 In addition, a region in contact with the semiconductor layer 108 is preferably formed using an oxide insulating film.

[0064] In addition, the gate insulating film 106 is provided with an insulating film having a blocking effect against oxygen, hydrogen, water, etc. By providing the insulating layer 104, oxygen can be diffused from the semiconductor layer 108 to the outside and oxygen can be diffused from the outside to the semiconductor layer 108. It can prevent hydrogen, water, etc. from entering. It has a blocking effect on oxygen, hydrogen, water, etc. Examples of insulating films that can be used include aluminum oxide, aluminum oxynitride, gallium oxide, and oxynitride. Gallium oxide, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride There are nium etc.

[0065] The gate insulating film 106 has a laminated structure, and the first silicon nitride film has few defects. A thin silicon nitride film is formed on the first silicon nitride film, and a second silicon nitride film is formed on the first silicon nitride film. A silicon nitride film with a low emission rate and ammonia emission rate is provided on the second silicon nitride film. By providing the oxide insulating film, the gate insulating film 106 can have few defects and can be formed without hydrogen or arsenic. As a result, the gate insulating film 106 that emits less ammonia can be formed. The hydrogen and nitrogen contained in the insulating film 106 are prevented from moving to the semiconductor layer 108. It is possible to do this.

[0066] Furthermore, by using a silicon nitride film for the gate insulating film 106, the following effects can be obtained: Silicon nitride film has a higher dielectric constant than silicon oxide film, and has the same capacitance. Since the film thickness required to obtain this is large, the gate insulating film can be physically made thicker. Therefore, the first transistor 101, the second transistor 103, and the third transistor The decrease in the dielectric strength voltage of the transistor 105 is suppressed, and furthermore, the dielectric strength voltage is improved, so that the transistor used in the display device Electrostatic breakdown of the transistor can be suppressed.

[0067] Furthermore, copper is used for the gate electrode 104, and the gate insulating film 10 When using a silicon nitride film for 6, in order to prevent the reaction between copper and ammonia molecules, The silicon nitride film is preferably formed to minimize the amount of ammonia molecules released by heating. I wish.

[0068] In the transistor using an oxide semiconductor film for the semiconductor layer 108, If there is a trap state (also called an interface state) at the interface of the gate insulating film or in the gate insulating film, The threshold voltage of a transistor varies, typically by a negative shift in the threshold voltage. The gate voltage required to change the drain current by one order of magnitude when the transistor is turned on is This causes an increase in the subthreshold coefficient (S value) of each transistor. Therefore, a gate insulating film with few defects is required. By using a silicon nitride film, the threshold voltage can be shifted negatively and the transistor This reduces variations in electrical characteristics.

[0069] The gate insulating film 106 is made of hafnium silicate (HfSiO x ), nitrogen is added Added hafnium silicate (HfSi x O y N z ), nitrogen-doped hafnium Luminate (HfAl x O y N z ), hafnium oxide, yttrium oxide, etc. The use of -k materials can reduce gate leakage of transistors.

[0070] The thickness of the gate insulating film 106 is 5 nm or more and 400 nm or less, and more preferably 10 nm or more. The thickness is preferably at most 300 nm, more preferably at least 50 nm and at most 250 nm.

[0071] The semiconductor layer 108 is made of an oxide semiconductor, and contains at least indium (In) or zinc It is preferable that the alloy contains (Zn). Alternatively, it is preferable that the alloy contains both In and Zn. In order to reduce variations in the electrical characteristics of transistors using the oxide semiconductor, It is preferable to have one or more stabilizers.

[0072] The stabilizers include gallium (Ga), tin (Sn), hafnium (Hf), and aluminum. Aluminum (Al) or zirconium (Zr), etc. Also, other stabilizers The lanthanides include lanthanum (La), cerium (Ce), and praseodymium ( Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium Er, Thulium, Ytterbium, Lutetium, etc. do.

[0073] For example, oxide semiconductors include indium oxide, tin oxide, zinc oxide, and In-Zn-based metals. metal oxides, Sn-Zn metal oxides, Al-Zn metal oxides, Zn-Mg metal oxides , Sn-Mg based metal oxides, In-Mg based metal oxides, In-Ga based metal oxides, In- W-based metal oxides, In-Ga-Zn-based metal oxides (also written as IGZO), In-Al -Zn-based metal oxides, In-Sn-Zn-based metal oxides, Sn-Ga-Zn-based metal oxides, Al-Ga-Zn metal oxide, Sn-Al-Zn metal oxide, In-Hf-Zn metal oxide Metal oxides, In-La-Zn metal oxides, In-Ce-Zn metal oxides, In-Pr -Zn-based metal oxides, In-Nd-Zn-based metal oxides, In-Sm-Zn-based metal oxides, In-Eu-Zn metal oxide, In-Gd-Zn metal oxide, In-Tb-Zn gold Metal oxides, In-Dy-Zn metal oxides, In-Ho-Zn metal oxides, In-Er -Zn-based metal oxides, In-Tm-Zn-based metal oxides, In-Yb-Zn-based metal oxides, In-Lu-Zn ​​metal oxide, In-Sn-Ga-Zn metal oxide, In-Hf-G a-Zn based metal oxides, In-Al-Ga-Zn based metal oxides, In-Sn-Al-Zn metal oxides, In-Sn-Hf-Zn metal oxides, In-Hf-Al-Zn metal acids Compounds can be used.

[0074] Here, for example, In-Ga-Zn-based metal oxide is a metal oxide mainly composed of In, Ga, and Zn. It means an oxide having In, Ga, and Zn as a component, and the ratio of In, Ga, and Zn does not matter. Metal elements other than n, Ga, and Zn may be included.

[0075] In addition, as an oxide semiconductor, InMO3(ZnO) m (m>0 and m is not an integer ) may be used, where M is selected from Ga, Fe, Mn and Co. In addition, the oxide semiconductor is In2SnO 5(ZnO) n A material expressed as (n>0 and n is an integer) may be used.

[0076] For example, In:Ga:Zn=1:1:1 (=1 / 3:1 / 3:1 / 3), In:Ga: Zn=2:2:1 (=2 / 5:2 / 5:1 / 5), or In:Ga:Zn=3:1: In-Ga-Zn metal oxide with an atomic ratio of 2 (= 1 / 2: 1 / 6: 1 / 3) and its composition Alternatively, an oxide having a ratio of In:Sn:Zn=1:1:1 (=1 / 3:1 / 3:1 / 3), In:Sn:Zn=2:1:3(=1 / 3:1 / 6:1 / 2) Or In with an atomic ratio of In:Sn:Zn=2:1:5 (=1 / 4:1 / 8:5 / 8) -Sn-Zn based metal oxides are recommended. The atomic ratio of metal oxides should be adjusted to account for the error. The above atomic ratios may vary by plus or minus 20%.

[0077] However, the semiconductor properties and electrical properties required (field effect mobility, etc.) are not limited to these. It is sufficient to use a material with an appropriate composition depending on the required characteristics (threshold voltage, variation, etc.). To obtain semiconductor properties, the carrier density, impurity concentration, defect density, metal element and oxygen atoms are It is preferable to make the numerical ratio, interatomic distance, density, etc. appropriate.

[0078] For example, high mobility can be obtained relatively easily with In-Sn-Zn metal oxides. However, even in In-Ga-Zn-based metal oxides, by reducing the defect density in the bulk, The field effect mobility can be increased.

[0079] In addition, an oxide semiconductor film that can be used as the semiconductor layer 108 may be an oxide semiconductor film containing an energy The gap is 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. In this way, by using an oxide semiconductor film with a wide energy gap, The off-state current can be reduced.

[0080] Next, the structure of an oxide semiconductor film that can be used as the semiconductor layer 108 will be described. do.

[0081] Oxide semiconductor films are roughly classified into non-single-crystal oxide semiconductor films and single-crystal oxide semiconductor films. The non-single-crystal oxide semiconductor film is a CAAC-OS (C Axis Aligned Crystal Polycrystalline oxide semiconductor film The oxide semiconductor film includes a film, a microcrystalline oxide semiconductor film, an amorphous oxide semiconductor film, and the like.

[0082] Here, we describe a CAAC-OS film.

[0083] The CAAC-OS film is one of the oxide semiconductor films with multiple crystal parts. The crystal part is small enough to fit inside a cube with a side length of less than 100 nm. The crystals contained in the OS film are cubes with sides of less than 10 nm, 5 nm, or 3 nm. This also includes cases where the size fits inside.

[0084] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a tron ​​microscope, clear boundaries between the crystals are observed. It is not possible to confirm the grain boundary. It can be said that the AAC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0085] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). When observed, it can be confirmed that metal atoms are arranged in layers in the crystalline part. Each layer of the CAAC-OS film is formed on a surface (also called a surface to be formed) or on a concave surface of the upper surface. The shape reflects the convexity and is aligned parallel to the surface on which the CAAC-OS film is formed or the upper surface.

[0086] On the other hand, the CAAC-OS film was observed by TEM from a direction approximately perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystalline region. However, no regularity was observed in the arrangement of metal atoms between different crystal regions. do not have.

[0087] In this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. Therefore, it also includes the case where the angle is between -5° and 5°. "Perpendicular" refers to two straight lines that form an angle of 80° or more and 100° or less. Therefore, the angle may be between 85° and 95°.

[0088] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It can be seen that this is the case.

[0089] X-ray diffraction (XRD) of the CAAC-OS film When structural analysis is performed using this device, for example, CAAC-OS with InGaZnO4 crystals can be seen. In the out-of-plane analysis of the film, the diffraction angle (2θ) peaks around 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis faces the surface on which the film is formed or the upper surface. It can be seen that the direction is roughly vertical.

[0090] On the other hand, the in-p X-rays incident on the CAAC-OS film are perpendicular to the c-axis. In the Lane analysis, a peak may appear around 2θ of 56°. The crystal structure of InGaZnO4 is composed of a single crystal of InGaZnO4. In the case of a nitride semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is the axis (φ axis). When the sample is rotated and analyzed (φ scan), a crystal plane equivalent to the (110) plane is detected. In contrast, in the case of the CAAC-OS film, six peaks are observed, which are assigned to 2θ. Even when the φ is fixed at around 56° and scanned, no clear peak appears.

[0091] From the above, it can be concluded that the orientation of the a-axis and b-axis is uniform between different crystal regions in the CAAC-OS film. Although it is irregular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface on which it is formed or the upper surface. Therefore, the layered structure confirmed by the cross-sectional TEM observation mentioned above is consistent with the Each layer of arranged metal atoms is a plane parallel to the ab plane of the crystal.

[0092] The crystalline part is formed when the CAAC-OS film is formed or after a crystallization treatment such as a heat treatment. As described above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is to be formed. Therefore, for example, in the CAAC-OS film, When the shape is changed by etching, the c-axis of the crystal is aligned with the CAAC-OS film. It may not be parallel to the normal vector of the face or top surface.

[0093] Furthermore, the crystallinity of the CAAC-OS film may not be uniform. When the crystalline part of the film is formed by crystal growth from the vicinity of the top surface of the CAAC-OS film, The area near the surface may have a higher crystallinity than the area near the surface to be formed. When impurities are added to the AC-OS film, the crystallinity of the region where the impurities are added changes, and the Regions of differing crystallinity may be formed.

[0094] In addition, the out-of-plane structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the NMR method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ around 36° is due to the (311) plane of the ZnGa2O4 crystal. Therefore, it is believed that the Z The CAAC-OS film shows that it contains nGa2O4 crystals. It is preferable that the peak is shown around 36° in 2θ and that the peak is not shown around 36° in 2θ.

[0095] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. The oxide semiconductor film is made of an element other than the main component, such as silicon or a transition metal element. The elements such as ZnO, which have stronger bonding strength with oxygen than the metal elements constituting the oxide semiconductor film, By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, and the crystallinity is reduced. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide are Because the diameter (or molecular radius) is large, when the molecule is contained inside the oxide semiconductor film, The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement of the oxide semiconductor film, which may result in a decrease in crystallinity. The pure material may act as a carrier trap or a carrier generation source.

[0096] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in semiconductor films can act as carrier traps and trap hydrogen. This can become a carrier generation source.

[0097] The low impurity concentration and low defect level density (low oxygen vacancies) are called high-purity intrinsic or The term "high-purity intrinsic" refers to a substantially high-purity intrinsic oxide semiconductor. Since the film has a small number of carrier generation sources, the carrier density can be reduced. The transistor using the oxide semiconductor film has electrical characteristics (noise) such that the threshold voltage is negative. It is also called "marine.") It is rare for it to become pure or substantially pure. An intrinsic oxide semiconductor film has few carrier traps. Transistors using this film have little fluctuation in electrical characteristics and are highly reliable. Note that it takes time for the charges trapped in the carrier traps in the oxide semiconductor film to be released. The time is long and the charge may behave as if it is fixed. Therefore, a transistor using an oxide semiconductor film with a high density of defect states has unstable electrical characteristics. This may be the case.

[0098] In addition, the electrical characteristics of transistors using CAAC-OS films are improved by irradiation with visible light or ultraviolet light. There is little gender variation.

[0099] The CAAC-OS film can be used as a polycrystalline oxide semiconductor sputtering target. The sputtering target is used to form a film. When ions collide, the crystalline regions contained in the sputtering target are cleaved from the ab plane. The particles are sputtered as flat or pellet-shaped particles with surfaces parallel to the ab plane. In this case, the plate-like sputtered particles may peel off while maintaining their crystalline state. By allowing the catalyst to reach the substrate in this state, a CAAC-OS film can be formed.

[0100] In addition, the following conditions are preferably applied to form the CAAC-OS film.

[0101] By reducing the amount of impurities mixed in during film formation, it is possible to prevent the crystal state from being destroyed by impurities. For example, the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be In addition, the impurity concentration in the deposition gas can be reduced. A deposition gas having a temperature of −80° C. or lower, preferably −100° C. or lower is used.

[0102] In addition, by increasing the substrate heating temperature during film formation, the microstructure of sputtered particles is improved after they reach the substrate. Specifically, the substrate heating temperature is set to 100°C or higher and 740°C or lower, preferably The film is formed at a temperature between 150°C and 500°C. When a flat sputtered particle reaches the substrate, migration occurs on the substrate. , the flat surface of the sputtered particle adheres to the substrate.

[0103] In addition, by increasing the oxygen ratio in the deposition gas and optimizing the power, plasma damage during deposition can be reduced. The oxygen ratio in the film forming gas is 30% by volume or more, preferably 100% by volume or more. Expressed as volume %.

[0104] In addition, the oxide semiconductor film used as the semiconductor layer 108 is a stack of a plurality of oxide semiconductor films. For example, the oxide semiconductor film may be formed by dividing a first oxide semiconductor film and a second oxide semiconductor film. As a stack of conductive films, a first oxide semiconductor film and a second oxide semiconductor film are stacked. For example, the first oxide semiconductor film may be formed using a binary metal oxide, a quaternary metal oxide, or a A second oxide semiconductor film is formed by using a metal oxide, and a second oxide semiconductor film is formed by using a binary metal oxide different from that of the first oxide semiconductor film. Metal oxides to quaternary metal oxides may also be used.

[0105] In addition, the first oxide semiconductor film and the second oxide semiconductor film are made to contain the same constituent elements, and the combination of the two films is For example, the atomic ratio of the first oxide semiconductor film may be set to In:Ga:Zn= The atomic ratio of the second oxide semiconductor film is set to In:Ga:Zn=1:1:1, and the atomic ratio of the second oxide semiconductor film is set to In:Ga:Zn=3:1:2. The atomic ratio of the first oxide semiconductor film may be In:Ga:Zn=1:3:2. The atomic ratio of In:Ga:Zn in the second oxide semiconductor film may be set to 2:1:3. The atomic ratio of each oxide semiconductor film is within the range of ±20% as an error. Includes fluctuations.

[0106] At this time, the first oxide semiconductor film and the second oxide semiconductor film that are closer to the gate electrode ( The content ratio of In to Ga in the oxide semiconductor film (on the channel side) is preferably In>Ga. The In and Ga contents of the oxide semiconductor film on the side far from the gate electrode (back channel side) are defined as In. It is recommended to set it to ≦Ga.

[0107] In addition, the oxide semiconductor film has a three-layer structure, and the first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film are The constituent elements of the first oxide may be the same, but the compositions of the first oxide and the second oxide may be different. The atomic ratio of the semiconductor film is In:Ga:Zn=1:3:2, and the atomic ratio of the second oxide semiconductor film is The atomic ratio of the third oxide semiconductor film is In:Ga:Zn=3:1:2. It is also possible to set a:Zn=1:1:1.

[0108] An oxide semiconductor film having a smaller atomic ratio of In than Ga and Zn, typically an oxide semiconductor film having a smaller atomic ratio of In The first oxide semiconductor film, in which Ga:Zn=1:3:2, has more In atoms than Ga and Zn atoms. An oxide semiconductor film having a large numerical ratio, typically a second oxide semiconductor film, and a film containing Ga, Zn, and compared with an oxide semiconductor film having the same atomic ratio of In and O, typically a third oxide semiconductor film, Since oxygen deficiency is unlikely to occur, an increase in carrier density can be suppressed. The first oxide semiconductor film has an atomic ratio of In:Ga:Zn=1:3:2 and has an amorphous structure. If the second oxide semiconductor film has such a structure, the second oxide semiconductor film tends to be a CAAC-OS film.

[0109] In addition, since the constituent elements of the first to third oxide semiconductor films are the same, The first oxide semiconductor film has a small number of trap states at the interface with the second oxide semiconductor film. Therefore, by using the oxide semiconductor film with the above structure, the transistor is less susceptible to deterioration over time and light. This can reduce the amount of variation in threshold voltage.

[0110] In oxide semiconductors, the s orbitals of heavy metals mainly contribute to carrier conduction, and the inclusion of In By increasing the ratio, more s orbitals overlap, resulting in an oxidation state where the composition is In>Ga. The material has a higher carrier mobility than oxides with a composition of In≦Ga. The formation energy of oxygen vacancies in is larger than that in In, so oxygen vacancies are less likely to occur in In≦ Oxides with a Ga composition have more stable properties than oxides with an In>Ga composition. do.

[0111] An oxide semiconductor with a composition of In>Ga is applied to the channel side, and In is applied to the back channel side. By using an oxide semiconductor having a composition of Ga≦Ga, the field-effect mobility and This makes it possible to further improve reliability.

[0112] In addition, the first to third oxide semiconductor films may be formed by using oxide semiconductors having different crystallinity. That is, a single crystal oxide semiconductor, a polycrystalline oxide semiconductor, a microcrystalline oxide semiconductor, A suitable combination of a crystalline semiconductor, an amorphous oxide semiconductor, or a CAAC-OS is also possible. In addition, it is preferable that an amorphous oxide film is formed in any one of the first oxide semiconductor film and the second oxide semiconductor film. By applying an oxide semiconductor, the internal stress and external stress of the oxide semiconductor film can be alleviated, and the transistor This reduces the variation in transistor characteristics and further improves transistor reliability. This becomes:

[0113] The thickness of the oxide semiconductor film is preferably 1 nm to 100 nm, more preferably 1 nm to 30 nm. nm or less, more preferably 1 nm to 50 nm, and even more preferably 3 nm to 20 nm It is preferable to do the following:

[0114] The oxide semiconductor film used for the semiconductor layer 108 was analyzed by secondary ion mass spectrometry (SIMS). Secondary Ion Mass Spectrometry The concentration of alkaline metals or alkaline earth metals is 1×10 18 atoms / cm 3 Below, More preferably 2×10 16 atoms / cm 3 The following is desirable: When metals and alkaline earth metals bond with an oxide semiconductor, they may generate carriers. This is because this causes an increase in the off-state current of the transistor.

[0115] In addition, the oxide semiconductor film used for the semiconductor layer 108 was analyzed by secondary ion mass spectrometry. The resulting hydrogen concentration is 5 x 10 18 atoms / cm 3 Less than 1 x 10 18 a toms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 Below are some more good ones: Preferably 1 x 10 16 atoms / cm 3 It is preferable to do the following:

[0116] Hydrogen contained in the oxide semiconductor film reacts with oxygen that is bonded to metal atoms to form water. However, defects are formed in the lattice from which oxygen has been removed (or in the part from which oxygen has been removed). In addition, when some of the hydrogen bonds with oxygen, electrons are generated as carriers. Therefore, by significantly reducing impurities including hydrogen in the film formation process of the oxide semiconductor film, Therefore, the hydrogen concentration in the oxide semiconductor film can be reduced. By using the removed oxide semiconductor film as a channel region, the threshold voltage can be reduced. This can suppress the fluctuation of the electrical characteristics. , leakage current at the source and drain of the transistor, typically, reducing the off-current. It is possible to reduce it.

[0117] The nitrogen concentration of the oxide semiconductor film used for the semiconductor layer 108 is set to 5×10 18 atoms / cm 3 By setting the threshold voltage of the transistor to the following, a negative shift can be suppressed. This makes it possible to reduce variations in electrical characteristics.

[0118] Note that the oxide semiconductor film is purified by removing hydrogen as much as possible, and is used as the channel region. The low off-state current of the transistor used in this study can be proven through various experiments. For example, the channel width is 1×10 6 Even if the transistor has a channel length of 10 μm, When the voltage between the source and drain electrodes (drain voltage) is in the range of 1V to 10V, The off-current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1×10 -13 Below A In this case, the off-state current is divided by the channel width of the transistor, The off-state current corresponding to the value is 100 zA / μm or less. The capacitor and the transistor are connected to each other to transfer the charge flowing into or out of the capacitor. The off-state current was measured using a circuit controlled by a transistor. A highly purified oxide semiconductor film is used in a channel region of a transistor, and a capacitor element is The off-state current of the transistor was measured from the change in the amount of charge per When the voltage between the source and drain electrodes of the transistor is 3V, the current is several tens of yA / μm. Therefore, it was found that a low off-state current can be obtained by using a highly purified oxide semiconductor film. The off-state current of the transistor used in the channel region is extremely small.

[0119] The source electrode 110 and the drain electrode 112 are made of conductive materials such as aluminum, Titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum Single layer structure of tungsten or tungsten alloy as the main component. For example, a single layer structure of aluminum film containing silicon, Two-layer structure with titanium film stacked on tungsten film, and two-layer structure with titanium film stacked on tungsten film Two-layer structure with copper film laminated on copper-magnesium-aluminum alloy film, titanium film or titanium nitride film, and an aluminum film or A three-layer structure in which a copper film is laminated and a titanium film or titanium nitride film is formed on top of that. A molybdenum film or molybdenum nitride film is overlaid on the molybdenum film or molybdenum nitride film. An aluminum film or copper film is laminated, and then a molybdenum film or molybdenum nitride film is further laminated on top of that. There are three-layer structures that form a transparent film. Transparent conductive materials may also be used.

[0120] In this embodiment, the source electrode 110 and the drain electrode 112 are formed on the semiconductor layer 108. However, it may be provided between the gate insulating film 106 and the semiconductor layer 108 .

[0121] The first interlayer insulating film 114 is formed on the interface with the oxide semiconductor film used as the semiconductor layer 108. In order to improve the surface characteristics, it is preferable to use an oxide insulating film. 4. Silicon oxide film and silicon oxynitride film with a thickness of 150 nm to 400 nm , aluminum oxide film, hafnium oxide film, gallium oxide film, or Ga-Zn based metal oxide The first interlayer insulating film 114 may be an oxide insulating film. For example, the first interlayer insulating film 114 may have a stacked structure of an oxide insulating film and a nitride insulating film. The silicon nitride film may have a laminated structure of a silicon oxynitride film and a silicon nitride film.

[0122] The second interlayer insulating film 116 may be made of an acrylic resin, a polyimide resin, a benzocyclopentasiloxane resin, or the like. Heat-resistant organic insulating materials such as butene resin, polyamide resin, and epoxy resin are used. By laminating multiple insulating films made of these materials, A second interlayer insulating film 116 may be formed. By using the second interlayer insulating film 116, Therefore, it is possible to flatten the unevenness of the first transistor 101 and the like.

[0123] The capacitance electrode 118 may be formed of indium oxide containing tungsten oxide, tungsten oxide, or the like. Indium zinc oxide containing titanium oxide, Indium oxide containing titanium oxide Indium tin oxide, indium tin oxide (hereinafter referred to as ITO), indium zinc oxide The transparent conductive material is an indium tin oxide doped with silicon oxide. It is possible.

[0124] The third interlayer insulating film 120 may be a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, or a silicon nitride oxide film. Inorganic insulating materials such as silicon film, silicon nitride film, and aluminum oxide film can be used. In particular, the third interlayer insulating film 120 may be a silicon nitride film, a silicon nitride oxide film, an oxide film, or the like. It is preferable that the film is one selected from the group consisting of a silicon nitride film, an aluminum nitride film, and an aluminum nitride film. The third interlayer insulating film is either a silicon nitride oxide film or an aluminum oxide film. By using the second interlayer insulating film 116 as the film 120, the release of hydrogen and moisture from the second interlayer insulating film 116 is suppressed. It can be controlled.

[0125] The pixel electrode 122 can be made of the same material as that used for the capacitor electrode 118. The materials used for the capacitor electrode 118 and the pixel electrode 122 may be the same or different. Although different materials may be used, it is preferable to use the same material since this reduces manufacturing costs.

[0126] The first alignment film 124 and the second alignment film 164 are made of acrylic resin, polyimide resin, or the like. Resins with heat resistance, such as benzocyclobutene resins, polyamide resins, and epoxy resins Organic materials that can be used can be used.

[0127] The liquid crystal layer 162 may be a thermotropic liquid crystal, a low molecular weight liquid crystal, a high molecular weight liquid crystal, or a polymer dispersion liquid crystal. Liquid crystal materials such as ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. can be used. Depending on the conditions, crystalline materials can be in a cholesteric phase, smectic phase, cubic phase, chiral phase, etc. It indicates a nematic phase, an isotropic phase, etc.

[0128] In addition, when the horizontal electric field method is adopted, the alignment film (the first alignment film 124 and the second alignment film 16 4) It is also possible to use a liquid crystal that exhibits a blue phase without using the above-mentioned compound. When the temperature of a cholesteric liquid crystal is increased, a transition from the cholesteric phase to the isotropic phase occurs. The blue phase is only manifested in a narrow temperature range, so in order to improve the temperature range, A liquid crystal composition in which several weight percent or more of a chiral agent is mixed is used for the liquid crystal layer. A liquid crystal composition containing a liquid crystal exhibiting the above property and a chiral agent has a short response time and is optically isotropic. Therefore, alignment treatment is not required, and the viewing angle dependency is small. This eliminates the need for rubbing, preventing electrostatic damage caused by rubbing. This makes it possible to reduce defects and damage to the liquid crystal display device during the manufacturing process. The productivity of the liquid crystal display device can be improved. The electrical characteristics of transistors can change significantly due to the effects of static electricity, causing them to deviate from their design range. Therefore, in a liquid crystal display device including a transistor including an oxide semiconductor film, It is more effective to use a liquid crystal material in the Lo phase.

[0129] The specific resistance of the liquid crystal material is 1×10 9 Ω·cm or more, preferably 1×10 1 1 Ω·cm or more, and more preferably 1×10 12 Ω·cm or more. The specific resistance values ​​in the specification are those measured at 20°C.

[0130] The size of the storage capacitor provided in the display device is determined by the lead of the transistor arranged in the pixel region. The capacitance is set to be able to hold charge for a predetermined period, taking into consideration factors such as the current flow. The thickness may be set in consideration of the off-state current of the transistor, etc. By using a transistor including an oxide semiconductor layer in which the resistance is suppressed, When a liquid crystal element is used, the capacitance of the liquid crystal element is preferably 1 / 3 or less of the capacitance of the liquid crystal element in each pixel. It is sufficient to provide a storage capacitor having a size of 1 / 5 or less.

[0131] In addition, the oxide semiconductor used in this embodiment is highly purified and in which the formation of oxygen vacancies is suppressed. The transistor used in the conductor layer must have a low current value in the off state (off current value). Therefore, the retention time of electrical signals such as image signals can be extended, and the power-on state In this state, the write interval can be set longer. Therefore, the frequency of refresh operations can be reduced. This has the effect of reducing power consumption.

[0132] In the display device shown in FIGS. 1 and 2, the liquid crystal element 150 is driven in the following modes: TN (Twisted Nematic) mode, IPS (In-Plane-Switch ching) mode, FFS (Fringe Field Switching) mode , ASM(Axially Symmetric aligned Micro-cel l) mode, OCB (Optical Compensated Birefringence nce) mode, FLC (Ferroelectric Liquid Crystal ) mode, AFLC (AntiFerroelectric Liquid Cryst In particular, to obtain a wide viewing angle, the FFS mode is used. It is preferable to do so.

[0133] In addition, normally black type liquid crystal display devices, for example, those employing vertical alignment (VA) mode The liquid crystal display device may be a transmission type. For example, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode Also, a pixel can be divided into several regions (sub-pixels). The molecules are divided into two parts, each of which is designed to tilt in a different direction. A method called multi-domain design may also be used.

[0134] Although not shown in FIGS. 1 and 2, a polarizing member, a phase difference member, an anti-reflection member, For example, a polarizing substrate and a retardation substrate may be provided. Circular polarization by the substrate may be used. Also, a backlight, a sidelight, etc. may be used as a light source. It may be used.

[0135] The display method in the pixel area 142 may be a progressive method or an interlace method. In addition, the color elements controlled by pixels when displaying colors include R It is not limited to the three colors of GB (R stands for red, G stands for green, B stands for blue). For example, RGBW (W stands for white), or RGB plus one or more colors such as yellow, cyan, or magenta. The size of the display area may differ for each dot of the color element. The present invention is not limited to color display devices, but may be applied to monochrome display devices. It can also be applied to

[0136] In addition, a spacer 160 is formed below the second substrate 152, and the first substrate 1 The gap between the substrate 102 and the second substrate 152 (also called the cell gap) is controlled by the The thickness of the liquid crystal layer 162 is determined by the cell gap. 60 is a columnar spacer obtained by selectively etching an insulating film, a spherical Any shape of spacer such as a spacer may be used.

[0137] The colored film 153 functions as a so-called color filter. It is sufficient to use a material that is transparent to light in a specific wavelength band, such as an organic material containing a dye or pigment. A resin film or the like can be used.

[0138] The light-shielding film 154 also functions as a so-called black matrix. The material must be able to block the emitted light between adjacent pixels, and it is necessary to use a metal film and a black dye or black pigment. In this embodiment, a black pigment is used. 1 shows an example of a light-shielding film 154 made of an organic resin film containing the organic compound.

[0139] The organic protective insulating film 156 is formed by dissolving the ionic substance contained in the colored film 153 in the liquid crystal layer. However, the organic protective insulating film 156 is not limited to this configuration. It is also possible to have a configuration in which it is not provided.

[0140] The sealing material 166 is a thermosetting resin or an ultraviolet curing resin. In the sealing region of the sealant 166 shown in FIG. 2 and the second substrate 152, a gate insulating film 106, a source electrode 110 and a drain electrode 111 are provided. The electrode 113, the first interlayer insulating film 114, and the second interlayer insulating film 115 are formed in the same process as the step 12. However, the present invention is not limited to this. For example, the gate insulating film 106 and Alternatively, the first interlayer insulating film 114 may be used alone. As shown in Figure 2, removing the second interlayer prevents moisture from entering from the outside. A structure in which a part of the insulating film 116 is removed or recessed is preferable.

[0141] As described above, the display device described in this embodiment mode has a pixel region and a driver circuit region. a first interlayer insulating film formed on the transistor; a second interlayer insulating film formed on the interlayer insulating film; and a third interlayer insulating film formed on the second interlayer insulating film. and a third interlayer insulating film provided on a part of the pixel region, The end of the film is formed inside the drive circuit region. This prevents outgassing from the second interlayer insulating film from entering the transistor side, resulting in high reliability. Furthermore, the first interlayer insulating film can be used to form a second interlayer insulating film. This can prevent outgassing from the film from entering the transistor side.

[0142] The structure shown in this embodiment mode may be combined as appropriate with structures shown in other embodiment modes or examples. It can be used as such.

[0143] (Embodiment 2) In this embodiment, a display device using an organic EL panel will be described as one form of the display device. 3 and 4, the same parts as those in the configuration shown in the first embodiment are shown. The detailed description thereof will be omitted.

[0144] As one embodiment of the display device, a top view of the display device is shown in FIG. 3, and a cross-sectional view of the display device is shown in FIG. 4 corresponds to a cross-sectional view taken along line X2-Y2 in FIG.

[0145] In the display device shown in FIG. 3, a pixel region 142 provided on a first substrate 102 and a pixel region 143 The gate electrode is a driving circuit area adjacent to the outside of the pixel area 142 and supplies signals to the pixel area 142. A sealant is placed around the gate driver circuit section 140 and the source driver circuit section 144. 166 is provided and sealed by the second substrate 152. a first substrate on which the gate driver circuit section 140 and the source driver circuit section 144 are provided; A second substrate 152 is provided to face the pixel region 142. The gate driver circuit section 140 and the source driver circuit section 144 are connected to the first substrate 102. The display element is sealed with a sealant 166 and a second substrate 152 .

[0146] In this way, a part or the whole of the driving circuit including the transistors can be formed in the same region as the pixel region 142. It can be integrally formed on the first substrate 102 to form a system on panel.

[0147] Next, referring to FIG. 4, which corresponds to a cross-sectional view taken along line X2-Y2 in FIG. 3, the pixel region 142 and The configuration of the gate driver circuit section 140 will be described in detail below.

[0148] In the pixel region 142, the first substrate 102 and the gate electrode formed on the first substrate 102 are a gate electrode 104, a gate insulating film 106 formed on the gate electrode 104, and a gate insulating film a semiconductor layer 108 provided in contact with the gate electrode 106 and overlapping the gate electrode 104; The source electrode 110 and the drain electrode 111 are formed on the insulating film 106 and the semiconductor layer 108. 12 form the first transistor 101.

[0149] In the pixel region 142, on the first transistor 101, more specifically, on the gate insulator The insulating film 106, the semiconductor layer 108, the source electrode 110, and the drain electrode 112 are covered with an inorganic A first interlayer insulating film 114 formed of an insulating material and an organic insulating film formed on the first interlayer insulating film 114. a second interlayer insulating film 116 formed of an inorganic insulating material; The third interlayer insulating film 120 formed by the above, the second interlayer insulating film 116, and the third interlayer insulating film The partition wall 126 formed on the film 120, the third interlayer insulating film 120, and the partition wall 126 formed on the The pixel electrode 122 is formed on the light-emitting layer 128, and the light-emitting layer 12 8 is formed on the electrode 130.

[0150] The pixel electrode 122, the light-emitting layer 128, and the electrode 130 form a light-emitting element 170. It has been completed.

[0151] Furthermore, a filler 172 is provided on the light emitting element 170, more specifically on the electrode 130. The second substrate 152 is provided on the filler 172. That is, the first substrate 102 The light emitting element 170 and the filler 172 are sandwiched between the first substrate 152 and the second substrate 152. do.

[0152] In addition, in the gate driver circuit section 140, the first substrate 102 and the first substrate 102 A gate electrode 104 is formed on the gate electrode 104. 6, and a semiconductor provided in contact with the gate insulating film 106 and at a position overlapping the gate electrode 104. layer 108, a gate insulating film 106, and a source electrode 110 formed on the semiconductor layer 108. and the drain electrode 112, the second transistor 103 and the third transistor A tub 105 is formed.

[0153] In addition, in the gate driver circuit section 140, the second transistor 103 and the third transistor On the transistor 105, more specifically, the gate insulating film 106, the semiconductor layer 108, the source electrode A first interlayer insulating film 11 made of an inorganic insulating material is formed on the electrode 110 and the drain electrode 112. 4, and a second interlayer insulating film 116 formed of an organic insulating material on the first interlayer insulating film 114. It is formed.

[0154] That is, the third interlayer insulating film 120 is provided on a part of the pixel region 142, and the third layer The end of the interlayer insulating film 120 is formed inside the gate driver circuit section 140, which is the drive circuit region. It is done.

[0155] By adopting such a configuration, moisture taken in from the outside or the inside of the display device can be prevented. The moisture and gases such as hydrogen generated in the gate driver circuit section 140 are removed from the second interlayer insulating film 116. Therefore, the first transistor 101 and the second transistor Moisture, hydrogen, and other gases are introduced into the third transistor 103 and the third transistor 105. This can suppress the

[0156] The second interlayer insulating film 116 made of an organic insulating material is a film that constitutes the display device. To reduce the unevenness of the transistor, an organic insulating material with high flatness is required. However, when heated, the organic insulating material converts hydrogen, moisture, or organic components into gas. It is released.

[0157] However, when the semiconductor layer 108 is made of, for example, a silicon film made of a silicon-based semiconductor material, In transistors, the above-mentioned hydrogen, moisture, and organic gases are a major problem. However, in one embodiment of the present invention, an oxide semiconductor film is used as the semiconductor layer 108. In order to use the second interlayer insulating film 116 made of an organic insulating material, gas is released to the outside. It is necessary to preferably release the electrons. Note that the end of the third interlayer insulating film 120 is the driving circuit region. The structure formed inside the gate driver circuit section 140 is such that the semiconductor layer 108 is made of an oxide. When the semiconductor layer 108 is formed from a semiconductor film, an excellent effect is obtained. Materials other than oxide semiconductors (e.g., silicon-based semiconductor materials such as amorphous silicon and crystalline silicon) The same effect can be obtained with a transistor made of silicon or the like.

[0158] In addition, the third interlayer insulating film 120 formed on the second interlayer insulating film 116 is In this state, gas released from the second interlayer insulating film 116 enters the light emitting element 170 side. and / or to improve the adhesion between the pixel electrode 122 and the second interlayer insulating film 116. This configuration allows the light emitting element 170 to be This can prevent gases such as hydrogen and moisture from entering through the second interlayer insulating film 116.

[0159] However, in the second embodiment, the third interlayer insulating film 120 is used for the gate driver circuit section 140. The second interlayer insulating film 116 is formed on the transistor 103 and the third transistor 105. When the insulating film 116 is formed, the gas released from the organic insulating material used for the second interlayer insulating film 116 is diffused to the outside. The second transistor 103 and the third transistor 105 cannot be dispersed. It gets in.

[0160] When the above-mentioned gas enters the oxide semiconductor used for the semiconductor layer 108 of the transistor, the oxide The semiconductor layer 108 is incorporated as an impurity in the oxide semiconductor film, and the characteristics of the transistor using the semiconductor layer 108 are improved. The gender changes.

[0161] However, as shown in FIG. 4, the second transistor used in the gate driver circuit section 140 103, and the third interlayer insulating film 120 on the third transistor 105 are opened; That is, the third interlayer insulating film 120 is provided in a part of the pixel region 142, and the third interlayer insulating film The end of the film 120 is formed inside the gate driver circuit section 140. Therefore, by adopting a structure that allows the gas released from the second interlayer insulating film 116 to be diffused to the outside, This can be done.

[0162] As shown in FIG. 4, in the first transistor 101 used in the pixel region 142, The third interlayer insulating film 120 made of an inorganic insulating material is also formed at the position where the semiconductor layer 108 overlaps. By adopting such a configuration, it is possible to form a thin film formed of an organic insulating material. Gas released from the second interlayer insulating film 116 enters the first transistor 101. This can suppress the

[0163] Here, other components of the display device shown in FIGS. 3 and 4 will be described with reference to the tables shown in the first embodiment. The differences from the device shown in FIG.

[0164] The partition wall 126 is formed using an organic insulating material or an inorganic insulating material. The resin material is used to form an opening on the pixel electrode 122, and the sidewall of the opening is a continuous curved It is preferable to form the inclined surface so as to have a certain slope.

[0165] The filler 172 may be an inert gas such as nitrogen or argon, or may be an ultraviolet curing resin or Alternatively, thermosetting resins can be used, such as PVC (polyvinyl chloride) and acrylic resins. , polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral ) or EVA (ethylene vinyl acetate) can be used. For example, filler 17 Nitrogen can be used as 2.

[0166] The light emitting element 170 may be a light emitting element that utilizes electroluminescence. The light-emitting element that uses electroluminescence uses an organic compound as the light-emitting material. Generally, the former are organic EL elements, and the latter are inorganic compounds. These are called inorganic EL elements. Here, we will explain using organic EL elements.

[0167] The organic EL element is configured such that, when a voltage is applied to the light emitting element, a pair of electrodes (pixel electrodes 122 and the electrode 130) into the layer containing the light-emitting organic compound. , current flows. Then, the carriers (electrons and holes) recombine, A light-emitting organic compound forms an excited state, and emits light when the excited state returns to the ground state. Due to this mechanism, such a light-emitting element is called a current-excited light-emitting element.

[0168] The light emitting element 170 has at least one pair of electrodes (pixel electrode 122 or The electrode 130 may be light-transmitting. The light emitted from the first substrate 102 side is emitted from the top surface, and the light emitted from the bottom surface is emitted from the first substrate 102 side. A double-sided emission structure in which light is emitted from the first substrate 102 side and the surface opposite to the first substrate 102. There are light emitting elements of any of these emission structures, and light emitting elements of any of these emission structures can be applied.

[0169] In addition, the electrodes are made of a material to prevent oxygen, hydrogen, moisture, carbon dioxide, etc. from entering the light emitting element 170. A protective film may be formed on the barrier ribs 130 and the barrier ribs 126. The protective film may be a silicon nitride film. A silicon nitride oxide film or the like can be formed. 152 and the space sealed by the sealing material 166 is provided with a filler 172 to seal the space. In this way, a protective film with high airtightness and low outgassing is used to prevent exposure to the outside air. Packaging (sealing) with film (lamination film, UV curing resin film, etc.) or cover material It is preferable to

[0170] If necessary, a polarizing plate or a circular polarizing plate (an elliptical polarizing plate) may be provided on the light-emitting surface of the light-emitting element 170. Optical films such as retardation films (λ / 4 plate, λ / 2 plate), and color filters are installed as needed. Alternatively, an anti-reflection film may be provided on the polarizing plate or the circular polarizing plate. The convex surface can be used to diffuse reflected light and reduce glare by applying an anti-glare treatment.

[0171] The light-emitting layer 128 is made of a light-emitting material that converts triplet excitation energy into light. A guest material and a host having a triplet excitation energy level (T1 level) higher than that of the guest material. It is preferable to use an organic compound containing a fluorine-containing material. Multi-layered structure (so-called tandem structure) and functional layers other than the light-emitting layer (hole injection layer, hole transport layer, an electron transport layer, an electron injection layer, a charge generation layer, etc.) may be included.

[0172] The sealing material 166 may contain glass material in addition to the materials shown in the first embodiment. Glass formed by melting and solidifying a material, such as powdered glass (also called frit glass). Such a material can effectively prevent the permeation of moisture and gas. Therefore, when the light emitting element 170 is used as a display element, deterioration of the light emitting element 170 is suppressed. This makes it possible to realize a highly reliable display device.

[0173] In addition, in the sealing region of the sealant 166 shown in FIG. 4, the first substrate 102 and the second substrate Although the configuration in which only the gate insulating film 106 is provided between the plates 152 has been exemplified, the present invention is not limited to this. For example, a configuration in which the gate insulating film 106 and the first interlayer insulating film 114 are stacked may be used. However, as shown in FIG. 4, in the region where the second interlayer insulating film 116 has been removed, A configuration in which a cooling material 166 is arranged is preferred.

[0174] As described above, the display device described in this embodiment mode has a pixel region and a driver circuit region. a first interlayer insulating film formed on the transistor; a second interlayer insulating film formed on the interlayer insulating film; and a third interlayer insulating film formed on the second interlayer insulating film. and a third interlayer insulating film provided on a part of the pixel region, The end of the film is formed inside the drive circuit region. This prevents outgassing from the second interlayer insulating film from entering the transistor side, resulting in high reliability. Furthermore, the first interlayer insulating film can be used to form a second interlayer insulating film. This can prevent outgassing from the film from entering the transistor side.

[0175] The structure shown in this embodiment mode may be combined as appropriate with structures shown in other embodiment modes or examples. It can be used as such.

[0176] (Embodiment 3) In this embodiment mode, an image display device which can be combined with the display device shown in the previous embodiment mode will be described. The sensor will now be described.

[0177] FIG. 5(A) shows an example of a display device with an image sensor. 1 is an equivalent circuit showing one pixel of a display device with a filter.

[0178] The photodiode element 4002 has one electrode connected to a reset signal line 4058 and the other electrode connected to a reset signal line 4058. The electrode is electrically connected to the gate electrode of transistor 4040. 0 means that either the source or drain electrode is connected to the power supply potential (VDD), and The other drain electrode is connected to one of the source and drain electrodes of the transistor 4056. The transistor 4056 has a gate electrode electrically connected to a gate selection line 4057. The other of the source electrode and the drain electrode is electrically connected to the output signal line 4071. .

[0179] The first transistor 4030 is a transistor for pixel switching. One of the source electrode or the drain electrode is connected to the video signal line 4059. The other electrode is electrically connected to the capacitor element 4032 and the liquid crystal element 4034. The gate electrode of the first transistor 4030 is electrically connected to a gate line 4036. do.

[0180] Note that the first transistor 4030, the capacitor 4032, and the liquid crystal element 4034 are The same structure as the display device shown in the first embodiment may be applied.

[0181] FIG. 5B is a cross-sectional view showing a part of one pixel of a display device with an image sensor, and a driving circuit In the pixel region 5042, a photodiode is disposed on the first substrate 4001. An electric field element 4002 and a first transistor 4030 are provided. In the gate driver circuit section 5040, which is a circuit, a second transistor is provided on the first substrate 4001. A transistor 4060 and a third transistor 4062 are provided.

[0182] The photodiode element 4002 and the first transistor in the pixel region 5042 On the sinter 4030, a first interlayer insulating film 4014, a second interlayer insulating film 4016, and a third interlayer insulating film 4017 are formed. An interlayer insulating film 4020 is formed on the second interlayer insulating film 4016. A capacitor element 4032 is formed using the interlayer insulating film 4020 as a dielectric.

[0183] That is, the third interlayer insulating film 4020 is provided in a part of the pixel region 5042, and the third The end of the interlayer insulating film 4020 is formed inside the gate driver circuit section 5040. By adopting such a configuration, the amount of the electrons released from the second interlayer insulating film 4016 is Therefore, the second interlayer insulating film 40 can have a structure that allows the gas to diffuse to the outside. This prevents outgassing from 16 from entering the transistor side, resulting in a highly reliable display device. It is possible.

[0184] The photodiode element 4002 is connected to the source electrode of the first transistor 4030 and The lower electrode is formed in the same process as the drain electrode, and the pixel electrode of the liquid crystal element 4034 is formed in the same process as the drain electrode. The upper electrode formed in one step is used as a pair of electrodes, and a diode is provided between the pair of electrodes. This is the configuration.

[0185] The diode that can be used for the photodiode element 4002 is a p-type semiconductor. pn-type diodes including stacks of p-type semiconductor films, i-type semiconductor films, and n-type semiconductor films A pin diode or a Schottky diode, which includes a laminate of conductive films, can be used. .

[0186] In addition, a first alignment film 4024 and a liquid crystal layer 4096 are disposed on the photodiode element 4002. , a second alignment film 4084, a counter electrode 4088, an organic insulating film 4086, a colored film 4085, 2 substrate 4052 and the like are provided.

[0187] In addition, pin-type diodes have higher photoelectric conversion characteristics when the light-receiving surface is the p-type semiconductor film side. This is because the hole mobility is smaller than the electron mobility. In this case, the photosensitive material is applied from the surface of the second substrate 4052 through the colored film 4085, the liquid crystal layer 4096, etc. 4002 is an example of a configuration in which light incident on the diode element 4002 is converted into an electrical signal. However, the present invention is not limited to this. For example, the colored film 4085 may not be provided.

[0188] The photodiode element 4002 shown in this embodiment is the same as the photodiode element 400 When light is incident on the photodiode 2, a current flows between the pair of electrodes. The light is detected by the light-emitting diode element 4002, and information about the object can be read.

[0189] The display device with an image sensor described in this embodiment mode is manufactured by a method for manufacturing a display, such as a transistor. By standardizing the equipment and image sensor processes, productivity can be increased. However, the display device described in the above embodiment and the image sensor described in this embodiment are different. Specifically, in the display device shown in the above embodiment, An image sensor may be fabricated on the second substrate.

[0190] This embodiment may be appropriately combined with the configurations described in other embodiments or examples. It is possible to implement.

[0191] (Fourth embodiment) In this embodiment, an example of a tablet terminal using a display device of one embodiment of the present invention will be described. do.

[0192] Figures 6(A) and 6(B) show a foldable tablet terminal. Figure 6(A) shows The tablet device is in an open state. The tablet device is made up of a housing 8630 and a housing 86 30, a display unit 8631a, a display unit 8631b, and a display mode changeover switch 8034, power switch 8035, power saving mode selector switch 8036, fastener 80 33 and an operation switch 8038.

[0193] The display device which is one embodiment of the present invention can be used for the display portion 8631a and the display portion 8631b. This can be done.

[0194] The display unit 8631a can function as a touch panel in part or in its entirety. For example, the entire display area 8631a can be touched to input the information. Keyboard buttons are displayed on the surface, which functions as a touch panel, and the display part 8631b is displayed. It may also be used as a screen.

[0195] In addition, like the display unit 8631a, a part or the whole of the display unit 8631b can be a touch panel. It can function as.

[0196] In addition, the touch panel area of ​​the display unit 8631a and the touch panel area of ​​the display unit 8631b You can also touch multiple areas at the same time.

[0197] The display mode changeover switch 8034 changes the display orientation, such as portrait or landscape. You can select between black and white and color display. Switch 8036 responds to external light detected by a light sensor built into the tablet device. The brightness of the display can be optimized by adjusting the brightness of the tablet. In addition, other detection devices such as a gyro or acceleration sensor that can detect tilt may be included. .

[0198] In addition, FIG. 6A shows an example in which the display portion 8631b and the display portion 8631a have the same area. However, there is no particular limitation. Even if the areas of the display section 8631b and the display section 8631a are different, The display quality may be different. For example, one may display a higher resolution image than the other. The display panel may also be a display panel.

[0199] FIG. 6B shows the tablet terminal in a closed state. 30, a solar cell 8633 and a charge / discharge control circuit 8634 provided in a housing 8630, 6B, a battery 86 is used as an example of the charge / discharge control circuit 8634. 35, shows a configuration having a DC-DC converter 8636.

[0200] In addition, since the tablet device can be folded in half, when not in use, the housing 8630 can be closed. Therefore, the display units 8631a and 8631b can be protected. It is highly durable and reliable for long-term use.

[0201] In addition, the tablet devices shown in Fig. 6(A) and Fig. 6(B) can also display various information. Functions that display (still images, videos, text images, etc.), calendars, dates, or times, etc. The function to display the information on the display, and the function to touch input or edit the information displayed on the display. It has input functions, functions to control processing by various software (programs), etc. It is possible.

[0202] The tablet device uses the power obtained by the solar cell 8633 to Alternatively, the power can be stored in the battery 8635. The solar cell 8633 may be provided on two surfaces of the housing 8630. In addition, if a lithium-ion battery is used as the battery 8635, it can be made smaller. What are the advantages?

[0203] The configuration and operation of the charge / discharge control circuit 8634 shown in FIG. 6B are shown in FIG. A block diagram is shown in Figure 6(C) and will be explained. 5, a DC / DC converter 8636, a converter 8637, a switch SW1, and a 6(C) shows the switch SW2, the switch SW3, and the display unit 8631. Battery 8635, DC / DC converter 8636, converter 8637, switch The switches SW1, SW2, and SW3 constitute a charge / discharge control circuit 86 shown in FIG. 6(B). Corresponds to 34.

[0204] When power is generated by the solar cell 8633, the power generated by the solar cell is transferred to the battery 8 The voltage is stepped up or down by the DC / DC converter 8636 to charge the 635. Next, the switch SW1 is turned on, and the converter 8637 supplies the optimum voltage to the display 8631. When the display on the display unit 8631 is not to be displayed, switch S Turn W1 off and turn on switch SW2 to charge the battery 8635.

[0205] Although the solar cell 8633 is shown as an example of the power generation means, it is not particularly limited. Instead, other power generation methods such as piezoelectric elements and thermoelectric elements are used. For example, a non-contact power transmission module that transmits and receives power wirelessly (contactlessly) for charging is also acceptable. It may also be configured to be performed in combination with other charging means such as a power cable.

[0206] This embodiment may be appropriately combined with the configurations described in other embodiments or examples. It is possible to implement.

[0207] (Embodiment 5) In this embodiment, an example of an electronic device equipped with the display device or the like described in the above embodiment will be described. and explain.

[0208] 7A shows a portable information terminal. The portable information terminal shown in FIG. 7A has a housing 930 0, a button 9301, a microphone 9302, a display unit 9303, and a speaker 93 9304 and a camera 9305, and has the function of a mobile phone. 03 is applied to the display device shown in the previous embodiment or / and the display device with an image sensor. It can be used.

[0209] FIG. 7B shows a display. The display shown in FIG. 7B is a display device mounted on a housing 9310. and a display portion 9311. The display portion 9311 may be any of the display devices described in the above embodiments. Or / and a display device with an image sensor can be applied.

[0210] Fig. 7(C) shows a digital still camera. The digital still camera shown in Fig. 7(C) The device includes a housing 9320, a button 9321, a microphone 9322, a display unit 9323, and The display portion 9323 may include the display device and / or the image display device described in the above embodiment. A display device with a sensor can be applied.

[0211] By using one embodiment of the present invention, the reliability of an electronic device can be improved.

[0212] This embodiment may be appropriately combined with the configurations described in other embodiments or examples. It is possible to implement. [Example]

[0213] In this embodiment, acrylic resin, which is a typical organic resin that can be used in a display device, is used. The gas released from the resin was investigated.

[0214] The sample was prepared by applying acrylic resin to a glass substrate and heating it at 250°C for 1 hour under a nitrogen gas atmosphere. The acrylic resin was heated to a thickness of 1.5 μm after the heat treatment. was formed.

[0215] The prepared samples were analyzed by TDS (Thermal Desorption Spectroscopy). The released gas was measured by thermal desorption spectroscopy.

[0216] FIG. 8 shows the mass-to-charge ratio (also called M / z) at a substrate surface temperature of 250° C. In FIG. 8, the horizontal axis represents the mass-to-charge ratio, and the vertical axis represents the intensity (arbitrary unit). From Figure 8, the mass-to-charge ratio of the sample is 18 (H 2O) and hydrocarbon-derived gases with mass-to-charge ratios of 28 (C2H4) and 44 (C3H 8) and 56 (C4H8). Each fragment ion was detected.

[0217] Similarly, Figure 9 shows the mass-to-charge ratios (18, 28, 44, and 56) versus the substrate surface temperature. In FIG. 9, the horizontal axis represents the substrate surface temperature (°C), and the vertical axis represents the ion intensity (arbitrary unit). When the substrate surface temperature was in the range of 55°C to 270°C, the water-induced The observed ion intensity of the mass-to-charge ratio of 18 is higher than 55°C and lower than 100°C, and higher than 150°C. It was found that there was a peak below 270°C. On the other hand, the mass-to-charge ratio, which is thought to be due to hydrocarbons, The ionic intensities of the ratios 28, 44, and 56 have peaks between 150°C and 270°C. I found out that...

[0218] As described above, water from organic resins, hydrocarbons, and other substances that are harmful to the oxide semiconductor film In particular, water is released at relatively low temperatures between 55°C and 100°C. That is, impurities originating from the organic resin reach the oxide semiconductor film. It was suggested that the electrical characteristics of the transistor would be degraded if the

[0219] In addition, organic resins are made into films that do not allow the passage of released gases such as water and hydrocarbons (silicon nitride films, nitride When the material is covered with a film such as silicon oxide or aluminum oxide, gas is released from the organic resin. This increases the pressure on the membrane, which is impermeable to released gases such as water and hydrocarbons, and eventually The film that does not allow released gases such as hydrogen chloride to pass through can be destroyed, resulting in defective transistor shapes. was suggested. [Example]

[0220] In this example, a transistor was fabricated, and its cross-sectional shape and electrical characteristics were evaluated.

[0221] Each sample has a bottom-gate / top-contact type channel-etched oxide semiconductor The transistor is provided on a glass substrate. a gate electrode formed on the gate electrode, a gate insulating film formed on the gate electrode, and a gate insulating film formed on the gate electrode. an oxide semiconductor film provided on the gate electrode; The gate electrode has a pair of electrodes, each of which is formed by a tungsten film. The insulating film is a silicon nitride film and a silicon oxynitride film on the silicon nitride film, which are oxide semiconductors. The body is an In-Ga-Zn oxide film, the pair of electrodes are tungsten films, and the electrode on the tungsten film An aluminum film and a titanium film on an aluminum film were used.

[0222] A protective insulating film (a silicon oxynitride film with a thickness of 450 nm and a silicon oxynitride film) is formed on the pair of electrodes. A 50 nm thick silicon nitride film is provided on the silicon film.

[0223] In addition, the example sample has a 2 μm thick acrylic resin layer on the protective insulating film. A 200 nm thick nitride layer was formed on the acrylic resin, exposing part of the side of the acrylic resin. The comparative sample has a silicon film with a thickness of 1.5 μm on the protective insulating film. Acrylic resin is provided, and 200n is applied to cover the acrylic resin. A silicon nitride film is provided with a thickness of m.

[0224] FIG. 10 shows a TEM transmission electron image of a magnified area of ​​the comparative sample. It is also called a scanned electron (TE) image. It shows the cross-sectional shape. was performed using Hitachi High-Technologies Corporation's "Hitachi Ultra-Thin Film Evaluation System HD-2300." In addition, only one of the pair of electrodes is shown in FIG. When attention is paid to the electrodes and the protective insulating film provided to cover the electrodes, the step formed by the electrodes It was found that a crack had occurred in the protective insulating film from the difference part. Since the example sample and the comparative example sample have roughly the same structure, the cross-sectional shape of the example sample is omitted.

[0225] Therefore, the sample of the example has a structure in which the gas released from the acrylic resin is released to the outside of the sample of the example. The comparative sample has a structure in which gas released from the acrylic resin does not escape to the outside of the comparative sample. That is, in the comparative example, the gas released from the acrylic resin does not escape to the outside, but is absorbed by the protective insulation. It was found that the electrons reached the transistor through cracks in the film.

[0226] Next, the electrical characteristics of the transistors of each sample, gate voltage (Vg) - drain current (I d) The Vg-Id characteristics were measured. The measurement was performed using a transistor. In measuring the Vg-Id characteristics, the drain voltage ( The gate voltage (Vd) was set to 1V or 10V, and the gate voltage (Vg) was swept from -20V to 15V.

[0227] The Vg-Id characteristics of each sample are shown in Figure 11. The glass substrate was 600 mm x 720 mm. The Vg-Id characteristics of 20 transistors were measured, as evenly as possible. 11(A) shows the Vg-Id characteristics and field-effect mobility of the transistor of the example sample, FIG. 11B shows the Vg-Id characteristics of the transistor of the comparative example. The field-effect mobility shown in Fig. 11 is the value at a drain voltage (Vd) of 10 V. In (B), calculation of the field-effect mobility was difficult and is therefore omitted.

[0228] As can be seen from FIG. 11A, the transistor of the example sample exhibits good switching characteristics. In addition, as shown in FIG. 11(B), in the transistor of the comparative example, It was found that the switching characteristics were not obtained and the device was always on.

[0229] By comparing with the example sample, the poor switching characteristics of the comparative sample were found to be due to the acrylic resin. Specifically, the acrylic resin The carrier density of the oxide semiconductor film increases due to the effect of the gas released from the gate electrode. Therefore, it is presumed that the transistor could not be turned off.

[0230] In this example, the organic resin is used as a membrane (here, thickness When the transistor is covered with a 200 nm thick silicon nitride film, the gas released from the organic resin It can be seen that this causes poor switching characteristics of the capacitor. A passageway for released gases to escape to the outside of the sample is provided in a part of the membrane that is impermeable to released gases such as hydrocarbons. By doing so, it is possible to avoid poor switching characteristics of the transistor, and to obtain good switching characteristics. You can see that you can get sexuality. [Explanation of symbols]

[0231] 101 first transistor 102 first substrate 103 Second transistor 104 gate electrode 105 Third Transistor 106 Gate insulating film 107 Capacitor element 108 Semiconductor layer 110 Source electrode 112 Drain electrode 113 Electrode 114 First interlayer insulating film 116 Second interlayer insulating film 118 Capacitive electrode 120 Third interlayer insulating film 122 pixel electrode 124 First alignment film 126 Bulkhead 128 Light-emitting layer 130 electrodes 140 Gate driver circuit section 142 pixel area 144 Source driver circuit section 146 FPC terminal section 148 FPC 150 Liquid crystal element 152 Second board 153 Colored film 154 Light-shielding film 156 Organic protective insulating film 158 Counter Electrode 160 spacer 162 Liquid crystal layer 164 Second alignment film 166 Sealing material 170 Light-emitting element 172 Filling material 4001 First substrate 4002 Photodiode element 4014 First interlayer insulating film 4016 Second interlayer insulating film 4020 Third interlayer insulating film 4024 First alignment film 4030 first transistor 4032 Capacitor 4034 Liquid crystal element 4036 Gate Line 4040 transistor 4052 Second board 4056 transistor 4057 Gate selection line 4058 Reset signal line 4059 Video signal line 4060 Second Transistor 4062 Third Transistor 4071 Output signal line 4084 Second alignment film 4085 Colored film 4086 Organic insulating film 4088 Counter electrode 4096 liquid crystal layer 5040 Gate driver circuit section 5042 pixel area 8033 Fasteners 8034 Switch 8035 Power Switch 8036 Switch 8038 Operation switch 8630 chassis 8631 Display section 8631a Display section 8631b Display section 8633 Solar Cells 8634 Charge / discharge control circuit 8635 battery 8636 DC / DC converter 8637 Converter 9300 chassis 9301 Button 9302 Microphone 9303 Display section 9304 Speaker 9305 Camera 9310 chassis 9311 Display section 9320 chassis 9321 Button 9322 Microphone 9323 Display section

Claims

1. a gate electrode; an oxide semiconductor layer overlapping the gate electrode; a gate insulating layer disposed between the gate electrode and the oxide semiconductor layer; a source electrode electrically connected to the oxide semiconductor layer; a transistor having a drain electrode electrically connected to the oxide semiconductor layer, the oxide semiconductor layer contains at least In and W, the oxide semiconductor layer includes a first film, a second film overlapping the first film, and a third film overlapping the second film; the first film and the second film have different crystallinity; the second film and the third film have different crystallinity; At least one of the first film, the second film, and the third film comprises a single-crystal semiconductor.

2. a gate electrode; an oxide semiconductor layer overlapping the gate electrode; a gate insulating layer disposed between the gate electrode and the oxide semiconductor layer; a source electrode electrically connected to the oxide semiconductor layer; a transistor having a drain electrode electrically connected to the oxide semiconductor layer, the oxide semiconductor layer contains at least indium oxide, the oxide semiconductor layer includes a first film, a second film overlapping the first film, and a third film overlapping the second film; the first film and the second film have different crystallinity; the second film and the third film have different crystallinity; At least one of the first film, the second film, and the third film comprises a single-crystal semiconductor.

3. a gate electrode; an oxide semiconductor layer overlapping the gate electrode; a gate insulating layer disposed between the gate electrode and the oxide semiconductor layer; a source electrode electrically connected to the oxide semiconductor layer; a transistor having a drain electrode electrically connected to the oxide semiconductor layer, the oxide semiconductor layer contains at least indium, The nitrogen concentration of the oxide semiconductor layer is 5×10 １８ atoms / cm ３ is as follows: the oxide semiconductor layer includes a first film, a second film overlapping the first film, and a third film overlapping the second film; the first film and the second film have different crystallinity; the second film and the third film have different crystallinity; At least one of the first film, the second film, and the third film comprises a single-crystal semiconductor.

4. In any one of claims 1 to 3, The semiconductor device, wherein the first film and the second film each have an energy gap of 2 eV or more.

5. In any one of claims 1 to 3, The semiconductor device, wherein the first film and the second film each have an energy gap of 2.5 eV or more.

6. In any one of claims 1 to 3, The semiconductor device, wherein the first film and the second film each have an energy gap of 3 eV or more.

7. In claim 1 or claim 2, The semiconductor device, wherein the oxide semiconductor layer has a nitrogen concentration of 5×10 18 atoms / cm 3 or less.

8. In any one of claims 1 to 7, The semiconductor device, wherein the oxide semiconductor layer includes at least one of a polycrystalline oxide semiconductor, a microcrystalline oxide semiconductor, and an amorphous oxide semiconductor.

9. In any one of claims 1 to 7, The semiconductor device, wherein the oxide semiconductor layer further contains one or more selected from the group consisting of gallium, tin, hafnium, aluminum, zirconium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

10. In any one of claims 1 to 7, The oxide semiconductor layer has an alkali metal or alkaline earth metal concentration of 1×10 １８ atoms / cm ３ The semiconductor device is as follows:

11. In any one of claims 1 to 7, The oxide semiconductor layer has a hydrogen concentration of 5×10 １８ atoms / cm ３ 4. A semiconductor device comprising:

12. In any one of claims 1 to 7, The semiconductor device, wherein the off-state current of the transistor is 1×10 −13 A or less.

13. In any one of claims 1 to 7, The semiconductor device, wherein the off-state current of the transistor is 100 zA / μm or less.

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