Semiconductor Device

Abstract

To suppress changes in the electrical characteristics of a display device including transistors in a pixel region and a drive circuit region and improve the reliability of the display device.SOLUTION: The display device includes: a first substrate in which a drive circuit region that is located outside and adjacent to a pixel region and includes at least one second transistor which supplies a signal to a first transistor included in each of the pixels in the pixel region, is formed; a second substrate provided to face the first substrate; and a liquid crystal layer held between the first substrate and the second substrate, and includes: a first interlayer insulating film formed of an inorganic insulating material over the first transistor and the second transistor; a second interlayer insulating film formed of an organic insulating material over the first interlayer insulating film; and a third interlayer insulating film formed of an inorganic insulating material over the second interlayer insulating film. The third interlayer insulating film is provided in part of an upper region of the pixel region, and has an edge portion formed on an inner side than the drive circuit region.SELECTED DRAWING: Figure 1

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 implemented by the peripheral ICs. Both are classified as having scanning circuits 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, the transistors used in the driver circuits are pixel transistors. The electrical properties (e.g., field effect mobility (μFE) or threshold voltage, etc.) used for the transistor In addition, 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 another material. 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 a semiconductor layer is a silicon-based semiconductor material. Since the field effect mobility is greater than that of transistors that use silicon as the semiconductor layer, the operating speed This is suitable for display devices with integrated driving circuits, and polycrystalline silicon is used for the semiconductor layer. The manufacturing process is easier than that of conventional transistors.

[0006] However, a transistor using an oxide semiconductor for a semiconductor layer is susceptible to hydrogen and moisture. 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, an oxide used as a channel forming region of a 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] JP 2006-165528 A [Patent Document 2] JP 2011-139047 A 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, and the like 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 region are electrically Since the load is large, the electrical characteristics of the transistors used in the driver circuit region are important.

[0011] In particular, a transistor using an oxide semiconductor film for a semiconductor layer is provided in a pixel region and a driver circuit region. In the display device used in the driving circuit area, the reliability test was conducted in a high temperature and high humidity environment. The degradation of transistors is a problem. The causes of the degradation of transistors are Moisture and other substances may penetrate from the organic insulating film formed on the photoresist 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 having 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 for a channel formation region of a transistor, This can suppress the intrusion of hydrogen and moisture into the oxide semiconductor film, thereby suppressing fluctuations in electrical characteristics. One of the objectives of both is to improve reliability. [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, a change in 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 by the oxide semiconductor film. The structure will be designed to make it difficult for worms to get into the building. More specifically, the structure is as follows:

[0014] One aspect of the present invention is a pixel electrode and at least one first transistor electrically connected to the pixel electrode. A pixel region in which multiple pixels including transistor 1 are arranged and an adjacent pixel region on the outside of the pixel region. 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 so as to face 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 and made of an organic insulating material. and a third interlayer insulating film formed of an inorganic insulating material on the second interlayer insulating film, 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 the display device is formed inside the above-mentioned area.

[0015] In the above-mentioned configuration, a first alignment film is provided on the pixel electrode, and a liquid crystal display 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 a counter 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 each including a 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 is provided so as to face the first substrate, and a semiconductor device is 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 is formed, and a second interlayer insulating film is formed of an organic insulating material on the first interlayer insulating film. an interlayer insulating film and a third interlayer insulating film formed on the second interlayer insulating film and made of 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 a driving circuit region.

[0017] In the above configuration, a light-emitting layer is provided on the pixel electrode, and an electrode is provided on the light-emitting layer;

[0043]

[0018] In each of the above structures, the third interlayer insulating film is a silicon nitride film or a silicon oxynitride film. It is preferable that the film is any one selected from the group consisting of an aluminum oxide 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 layer formed on the gate electrode. and a source electrode and a drain electrode formed on the semiconductor layer. It is preferable that the above-mentioned configuration be adopted.

[0020] In addition, one embodiment of the present invention includes in its category an electronic device having a display device having any of the above configurations. It is. Effect 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 transistor channel 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 matter, suppresses fluctuations in electrical characteristics, and improves reliability. do. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 illustrates a top surface of one embodiment of a display device. [Diagram 2] FIG. 1 illustrates a cross section of one embodiment of a display device. [Diagram 3] FIG. 1 illustrates a top surface of one embodiment of a display device. [Figure 4] FIG. 1 illustrates a cross section of one embodiment of a display device. [Diagram 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. 1 illustrates an example of a tablet terminal according to one embodiment of the present invention. [Figure 7] 1A to 1C are diagrams illustrating examples of electronic devices according to one embodiment of the present invention. [Figure 8] FIG. 4 is a graph showing the ion intensity of emitted gas at each mass-to-charge ratio. [Figure 9] FIG. 13 is a graph showing ion intensity at each mass-to-charge ratio versus substrate surface temperature. [Figure 10] Cross-sectional image of a sample. [Figure 11] FIG. 11 shows electrical characteristics of each sample. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description, and it is understood by those skilled in the art that various changes can be made in form and detail. The present invention is not limited to the description of the following 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. In addition, the thicknesses and widths of the components, i.e., layers and regions, and the relative positional relationships shown in the drawings are not necessarily the same. 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 intended to be limiting. For example, an "electrode" may be used as a part of a "wire." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably to refer to the plural "electrodes" and "wirings." This also includes cases where the wiring is formed integrally.

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

[0027] In addition, the functions of "source" and "drain" may differ when using transistors with different polarities. In some cases, such as when the direction of the current changes during circuit operation, the two may be interchanged. 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. This will be explained with reference to FIG. 1 and FIG. 2.

[0029] 1A, 1B, and 1C are top views of a display device as one embodiment of the display device. FIG. 1A shows the entire display device, and FIG. 1B shows a part of the drive circuit unit of the display device. FIG. 1C shows a top view of a part of the pixel region. FIG. 2 shows the same structure as FIG. 1A. This corresponds to a cross-sectional view taken along line X1-Y1 in FIG.

[0030] In the display device shown in FIG. 1A, a pixel region 142 is provided on a first substrate 102. and a driving circuit region adjacent to the outside of the pixel region 142 for supplying signals to the pixel region 142. The gate driver circuit section 140 and the source driver circuit section 144 are surrounded by a shield. A sealing material 166 is provided and sealed by a second substrate 152. 42, and a first transistor in which a gate driver circuit section 140 and a source driver circuit section 144 are provided. A 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 second substrate 152 and the sealing material 166 .

[0031] In FIG. 1A, the first substrate 102 is surrounded by a sealant 166. In a region different from the region where the pixel region 142, the gate driver circuit section 140, the source driver The FPC terminal portion 146 (FPC: Flexib The FPC terminal portion 146 is provided with a 1 / 4" printed circuit. The FPC 148 is connected to the pixel region 142, the gate driver circuit section 140, and the source driver Various signals and potentials are provided to the driver circuit section 144 through an FPC 148. There are.

[0032] In FIG. 1A, the gate driver circuit section 140 and the source driver circuit section In the example shown, the pixel region 142 and the first substrate 102 are formed with the pixel region 144. For example, only the gate driver circuit section 140 may be formed on the first substrate 102. A substrate (e.g., 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, Alternatively, the gate driver circuit section 140 may be arranged on only one side of the substrate 142 .

[0034] The method of connecting the separately formed drive circuit board is not particularly limited, and may be any method such as COG (Chip On Glass) method, wire bonding method, or TAB (Tap The Automated Bonding method 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 is 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 FIG. 1C, the first transistor 101 and the capacitor are disposed in the pixel region 142. The first transistor 101 has a gate electrode 107 formed thereon with respect to the semiconductor layer 108. A gate electrode 104, a source electrode 110, and a drain electrode 112 are electrically connected to each other. In addition, although not shown in the plan view shown in FIG. 1C, the first transistor A first interlayer insulating film made of an inorganic insulating material is formed on the photoresist 101. 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 capacitance element 107 has a capacitance 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 region, 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 line including the gate electrode 104 is A source line including a source electrode 110 extends in the vertical direction, and a drain electrode 11 2 extends in the vertical direction 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 area 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 unit 1 can be driven with a voltage of about several volts to about 20 volts. The second transistor 103 and the third transistor 105 in the pixel region 1 In comparison with the first transistor 101 in 42, the structure to which the stress is applied is very large. It becomes.

[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 views 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 is provided in contact with the gate electrode 106 and overlaps the gate electrode 104. A source electrode 110 and a drain electrode 111 are formed on the insulating film 106 and the semiconductor layer 108. 12 forms a first transistor 101.

[0042] In the pixel region 142, the first transistor 101, more specifically, 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 are The electrode 118, the second interlayer insulating film 116 and the capacitance electrode 118 are formed of an inorganic insulating material. a third interlayer insulating film 120, a pixel electrode 122 formed on the third interlayer insulating film 120; It has.

[0043] The capacitance electrode 118, the third interlayer insulating film 120, and the pixel electrode 122 form a capacitance. The element 107 is formed. A capacitance electrode 118, a third interlayer insulating film 120, and a 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 capacity 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 is formed on the liquid crystal layer 162, a second alignment film 164 is formed on the liquid crystal layer 162, and the second alignment film A counter electrode 158 provided on the substrate 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 a 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 provided in contact with the gate insulating film 106 and at a position overlapping the gate electrode 104. 8, 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 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 is 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. The end of the interlayer insulating film 120 is formed inside the gate driver circuit section 140 which is the driving circuit region. It is done.

[0049] By adopting such a configuration, moisture taken in from the outside or moisture inside the display device The moisture and gas 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. It is possible to suppress the above.

[0050] The second interlayer insulating film 116 made of an organic insulating material constitutes a display device. In order to reduce the unevenness of the transistor, an organic insulating material with high flatness is required. This can improve the image quality of a display device by reducing the unevenness of a transistor. However, the organic insulating material is easily degraded 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 formed as the semiconductor layer 108. In order to use the second interlayer insulating film 116 made of an organic insulating material, gas is discharged to the outside. It is necessary to preferably emit the radiation. Note that the end of the third interlayer insulating film 120 is the driving circuit region. The structure formed on the inner side of the gate driver circuit section 140 is a structure in which the semiconductor layer 108 is made of an oxide. When the semiconductor layer 108 is made of 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 The same effect can be obtained with a transistor formed of a material other than silicon.

[0052] In addition, 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 above is a dielectric film for the capacitor element 107. The third interlayer insulating film 120 made of an inorganic insulating material is used as a conductor. Therefore, it is possible to suppress hydrogen, moisture, and the like from penetrating into the second interlayer insulating film 116.

[0053] However, in the second embodiment in which 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 described above 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 transistors using 08 will fluctuate.

[0055] However, as shown in FIG. 2, the second transistor used in the gate driver circuit unit 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 making the structure capable of diffusing gas released from the second interlayer insulating film 116 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 disposed at the position where the semiconductor layer 108 overlaps. In this way, the insulating layer formed of the organic insulating material is preferably removed. 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 FIG. 1 and FIG. 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 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 (2950 mm x 3400 mm). Mother glass shrinks significantly when the processing temperature is high and the processing time is long. When mass production is carried out using a quartz crystal, the heat treatment in the manufacturing process is preferably performed at 600° C. or less, and more preferably 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. Kon film, gallium oxide film, hafnium oxide film, yttrium oxide film, aluminum oxide film The base insulating film may be a silicon nitride film, a gas oxide film, or an aluminum oxide nitride film. The material may be a hafnium oxide film, 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 intrusion of the 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 elements; The above-mentioned metal elements can be combined to form an alloy or the like. Alternatively, one or more metal elements selected from the group consisting of tin, zinc, zirconium, and zinc oxide 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 it, Two-layer structure with a titanium film laminated on a titanium nitride film, and a tungsten film laminated 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 laminated on top of the titanium film, and titanium 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 tenon, molybdenum, chromium, neodymium, and scandium, or a combination of these elements. Combined alloy films or nitride films may also be used.

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

[0062] In addition, an In-Ga-Zn-based oxynitride is formed between the gate electrode 104 and the gate insulating film 106. Semiconductor film, In-Sn-based oxynitride semiconductor film, In-Ga-based oxynitride semiconductor film, In-Zn Sn-based oxynitride semiconductor film, In-based oxynitride semiconductor film, metal nitride film ( InN, ZnN, etc.) may be provided. These films have a thermal conductivity of 5 eV or more, preferably 5.5 eV or more. Since the work function 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, so that the so-called normal For example, an In-Ga-Zn oxynitride semiconductor 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 is 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, the diffusion of oxygen from the semiconductor layer 108 to the outside and the diffusion of oxygen from the outside to the semiconductor layer 108 can be prevented. 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 nitridium oxide. Gallium oxide, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride Nium, etc.

[0065] In addition, the gate insulating film 106 has a laminated structure, and is formed as a first silicon nitride film, so that the gate insulating film 106 has few defects. A silicon nitride film having a thickness of 100 nm was formed on the first silicon nitride film. A second silicon nitride film having a thickness of 100 nm was formed on the first silicon nitride film. A silicon nitride film having 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 being resistant to hydrogen and arsenic. It is possible to form a gate insulating film 106 that emits less ammonia. The hydrogen and nitrogen contained in the insulating film 106 are prevented from migrating to the semiconductor layer 108. It is possible.

[0066] In addition, 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 a large film thickness is required to obtain this, the gate insulating film can be physically thickened. Therefore, the first transistor 101, the second transistor 103, and the third transistor The decrease in the dielectric strength of the transistor 105 is suppressed, and further the dielectric strength is improved, so that the transistor used in the display device can be used Electrostatic damage to the transistor can be suppressed.

[0067] In addition, copper is used as the gate electrode 104, and the gate insulating film 10 When using a silicon nitride film for 6, in order to suppress the reaction between copper and ammonia molecules, It is preferable that the silicon nitride film is capable of reducing the amount of ammonia molecules released by heating as much as possible. I wish.

[0068] In a transistor in which an oxide semiconductor film is used 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 in the negative direction. 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. For this reason, a gate insulating film with fewer defects is required. By using a silicon nitride film, the threshold voltage is shifted negatively and the current of the transistor is This can reduce the variation in thermal 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 ), hafnium aluminium doped with nitrogen Luminate (HfAl x O y N z ), hafnium oxide, yttrium oxide and other high The use of -k materials can reduce gate leakage of transistors.

[0070] The thickness of the gate insulating film 106 is preferably 5 nm or more and 400 nm or less, more preferably 10 nm or less. The thickness is preferably at most 300 nm, and 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 (Zn). 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 electrical characteristics of transistors using the oxide semiconductor, It is preferable to have one or more stabilizers.

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

[0073] For example, oxide semiconductors include indium oxide, tin oxide, zinc oxide, and In-Zn-based metal oxides. metal oxides, Sn-Zn metal oxides, Al-Zn metal oxides, Zn-Mg metal oxides , Sn-Mg metal oxides, In-Mg metal oxides, In-Ga metal oxides, In- W-based metal oxide, In-Ga-Zn-based metal oxide (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 metal oxide, In-Al-Ga-Zn metal oxide, In-Sn-Al-Zn metal oxides, In-Sn-Hf-Zn metal oxides, In-Hf-Al-Zn metal acids Compounds such as fluorine-containing fluorine compounds can be used.

[0074] In this case, for example, In-Ga-Zn-based metal oxide is a metal oxide mainly composed of In, Ga, and Zn. The ratio of In, Ga, and Zn does not matter. Metal elements other than n, Ga, and Zn may be present.

[0075] In addition, InMO 3 (ZnO) m (m>0 and m is not an integer In addition, M is selected from Ga, Fe, Mn, and Co. The metal element or elements are also included as oxide semiconductors. 2 SnO 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 metal oxides are recommended. Note that the atomic ratio of metal oxides should be adjusted to allow for error. The above atomic ratios may vary by ±20%.

[0077] However, the present invention is not limited to these, and the semiconductor properties and electrical properties required (field effect mobility, etc.) It is sufficient to use a material with an appropriate composition according to 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. At the same time, the In-Ga-Zn metal oxides can also be fabricated by reducing the bulk defect density. The field effect mobility can be increased.

[0079] In addition, an oxide semiconductor film that can be used for the semiconductor layer 108 may be 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 current can be reduced.

[0080] Next, a 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 called CAAC-OS (C Axis Aligned Crystal-Oxide Semiconductor Film). (stalline oxide semiconductor) film, polycrystalline oxide semiconductor 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 that has multiple crystal parts. The crystal part is small enough to fit inside a cube with one side less than 100 nm. The crystal parts contained in the OS film are cubes with one side less than 10 nm, 5 nm, or 3 nm. This also includes cases where the size fits within the

[0084] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed using a quartz crystal microscope, clear boundaries between crystal parts were observed, i.e. 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 the metal atoms are observed, it can be confirmed that they are arranged in layers in the crystal part. Each layer of the CAAC-OS film is formed on a surface on which the film is to be formed (also called a surface on which the film is to be formed) or on a concave surface on the upper surface. The shape reflects a 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 roughly perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystals. 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 includes the case where the angle is between -5° and 5°. "Perpendicular" refers to two straight lines that form an angle between 80° and 100°. Therefore, cases between 85° and 95° are also included.

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

[0089] X-ray diffraction (XRD) of CAAC-OS film When the structure is analyzed using the device, for example, InGaZnO 4 CAAC-OS with crystals of In the out-of-plane analysis of the film, the diffraction angle (2θ) peaked at around 31°. This peak may appear in InGaZnO 4 It is assigned to the (009) plane of the 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 it is oriented in a roughly vertical direction.

[0090] On the other hand, in-p X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In the lane method, a peak may appear at 2θ around 56°. InGaZnO 4 It is attributed to the (110) plane of the InGaZnO crystal. 4 Single crystal of acid 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 Even when φ is fixed at around 56° and scanned, no clear peak appears.

[0091] From the above, it is considered 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 in 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 process such as a heat treatment. As described above, the c-axis of the crystal is aligned to the surface on which the CAAC-OS film is to be formed. 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 face or top surface normal vector.

[0093] In addition, the crystallinity in the CAAC-OS film does not have to 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 on which it is formed. When impurities are added to the AC-OS film, the crystallinity of the region to which the impurities are added changes, resulting in a partial In some cases, regions of differing crystallinity may be formed.

[0094] In addition, InGaZnO 4 Out-of-plane crystallographic structure of CAAC-OS film In the analysis by the method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ of around 36° is due to ZnGa 2 O 4 On the (311) face of the crystal Since it is attributed to InGaZnO 4 In a part of the CAAC-OS film having crystals of nGa 2 O4 The CAAC-OS film shows that it contains crystals with a 2θ of approximately 31°. It is preferable that the peak be present near the 2θ value of 36° and that the peak be absent near the 2θ value of 36°.

[0095] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. The oxide semiconductor film is preferably made of silicon or a transition metal element other than the main component of the oxide semiconductor film. The elements that bond to oxygen stronger than the metal elements that form the oxide semiconductor film, such as Zn, By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disturbed, and the crystallinity is reduced. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide are Since the diameter (or molecular radius) of the ions is large, when the ions are contained inside the oxide semiconductor film, the oxide semiconductor film The impurities contained in the oxide semiconductor film are disturbed, which causes a decrease in crystallinity. Pure materials may act as carrier traps or carrier generation sources.

[0096] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in semiconductor films 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 carrier generation source, the carrier density can be reduced. The transistor using the oxide semiconductor film has electrical characteristics (noise) in which the threshold voltage is negative. It is also called "marine". It is rare for it to become "high purity genuine" or "substantially high purity". The intrinsic oxide semiconductor film has few carrier traps. Transistors using the film have little fluctuation in electrical characteristics and are highly reliable. Note that it takes a certain time for 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 were a fixed charge. In addition, a transistor using an oxide semiconductor film having a high density of defect states has unstable electrical characteristics. There may be cases where this occurs.

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

[0099] In addition, the CAAC-OS film can be used as a sputtering target for a polycrystalline oxide semiconductor. The sputtering method is used to form a film using the sputtering target. When ions collide, the crystalline regions in the sputtering target are cleaved from the ab plane. The particles are sputtered as flat or pellet-shaped particles with faces parallel to the ab plane. In this case, the plate-like sputtered particles may peel off while maintaining their crystalline state. By reaching 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 deposition chamber can be In addition, the impurity concentration in the deposition gas may 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 and 500°C. By increasing the substrate heating temperature during film formation, When a flat sputtered particle reaches a 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 is reduced. The oxygen ratio in the deposition gas is preferably 30% by volume or more, and more preferably 100% by volume or more. Expressed as volume percent.

[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 a structure in which a first oxide semiconductor film and a second oxide semiconductor film are stacked. As a stack of conductive films, a first oxide semiconductor film and a second oxide semiconductor film are formed by stacking gold layers having different compositions. For example, the first oxide semiconductor film may be formed using a binary metal oxide, a quaternary metal oxide, or a quaternary 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 elements. For example, the atomic ratio of the first oxide semiconductor film may be set to In:Ga:Zn= The atomic ratio of the first oxide semiconductor film is 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, whichever is closer to the gate electrode ( The content ratio of In and 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 farther from the gate electrode (the 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 first oxide may have the same constituent elements and different compositions. For example, 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. a:Zn=1:1:1 may also be used.

[0108] An oxide semiconductor film having a smaller atomic ratio of In than Ga and Zn, typically an oxide semiconductor film having an atomic ratio of In The first oxide semiconductor film has a composition of Ga:Zn=1:3:2, and the first oxide semiconductor film has more In atoms than Ga and Zn atoms. The oxide semiconductor film having a large numerical ratio, typically the second oxide semiconductor film, and the oxide semiconductor film having Ga, Zn, and compared with an oxide semiconductor film having the same atomic ratio of In and In, 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 such a film is present, the second oxide semiconductor film tends to be a CAAC-OS film.

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

[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 oxide with a composition of 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 or less, the field-effect mobility and This makes it possible to further improve reliability.

[0112] In addition, the first to third oxide semiconductor films may include 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 can also be used. In addition, any one of the first oxide semiconductor film, the second oxide semiconductor film, and the like may be formed using an amorphous oxide semiconductor film. By applying an oxide semiconductor, the internal stress and external stress of the oxide semiconductor film can be reduced, and the transistor can be This reduces the variation in transistor characteristics and further improves the reliability of the transistor. It 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 that:

[0114] In the oxide semiconductor film used for the semiconductor layer 108, secondary ion mass spectrometry (SIMS: Secondary Ion Mass Spectrometry (SIMMS) 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 It is preferable that the alkaline gold When metals and alkaline earth metals are bonded to an oxide semiconductor, they may generate carriers. This is because it causes an increase in the off-state current of the transistor.

[0115] In addition, in the oxide semiconductor film used for the semiconductor layer 108, The resulting hydrogen concentration is 5×10 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 Preferably 1×10 16 atoms / cm 3 It is preferable that:

[0116] Hydrogen contained in the oxide semiconductor film reacts with oxygen that is bonded to metal atoms to form water. In the lattice from which oxygen has been removed (or in the portion from which oxygen has been removed), defects are formed. In addition, when some of the hydrogen bonds with oxygen, electrons that act as carriers are generated. Therefore, by drastically 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 is reduced. It is possible to suppress the fluctuation of the electrical characteristics. The leakage current at the source and drain of the transistor is typically reduced by reducing the off-current. It is possible to reduce

[0117] In addition, 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 negative shift, This makes it possible to reduce the variation 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 transistors used in the 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 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-current corresponding to the value is 100zA / 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 for a channel region of a transistor, and The off-state current of the transistor was measured based on 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 material such as aluminum, Titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum The alloy mainly composed of tungsten or tungsten is used in a single layer structure. For example, a single layer structure of an aluminum film containing silicon, Two-layer structure with titanium film laminated on tungsten film, two-layer structure with titanium film laminated on tungsten film A two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a titanium film, or titanium nitride film, and 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 laminated on the molybdenum film or molybdenum nitride film. An aluminum film or a copper film is laminated, and a molybdenum film or a molybdenum nitride film is further laminated on top of that. In addition, transparent films containing indium oxide, tin oxide, or zinc oxide are also available. 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 a thin film having a thickness of 100 nm to 100 nm. In order to improve surface characteristics, it is preferable to use an oxide insulating film. 4 is a silicon oxide film or a silicon oxynitride film having a thickness of 150 nm or more and 400 nm or less. , 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 benzocyclopentadiene resin, or the like. Heat-resistant organic insulating materials such as butene resins, polyamide resins, and epoxy resins are used. In addition, by stacking a plurality of 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 material used is a conductive material with transparency, such as indium tin oxide doped with silicon oxide or 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 oxynitride 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 any one selected from the group consisting of a silicon nitride film, an aluminum nitride film, and an aluminum oxide film. A third interlayer insulating film is formed by using one of a silicon oxynitride film and 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 may be made of the same material as the capacitance electrode 118. The materials used for the capacitance electrode 118 and the pixel electrode 122 may be the same or different. Although the same material 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, etc. Resins with heat resistance, such as benzocyclobutene resins, polyamide resins, and epoxy resins. Organic materials that 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, the crystal material can have a cholesteric phase, a smectic phase, a cubic phase, or a chiral phase. It indicates a nematic phase, an isotropic phase, etc.

[0128] In addition, when the in-plane switching method is adopted, the alignment film (the first alignment film 124 and the second alignment film 16 4) A liquid crystal that exhibits a blue phase without using the above-mentioned compound may be used. When the temperature of a cholesteric liquid crystal is increased, a phenomenon occurs immediately before the transition from the cholesteric phase to the isotropic phase. 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 a chiral agent is mixed in an amount of several weight percent or more is used for the liquid crystal layer. A liquid crystal composition containing a liquid crystal exhibiting the above-mentioned 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, resulting in deviation from the 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 loose 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 ​​specified 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 so that the charge can be held for a certain period of time, taking into account the capacitance of the capacitor. 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 suppression of the noise is suppressed, When a liquid crystal element is used, the capacitance of the liquid crystal in each pixel is preferably 1 / 3 or less. 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 that is highly purified and in which the formation of oxygen vacancies is suppressed is used as a semiconductor. The transistors used in the conductor layer must have a low current value in the off state (off current value). This makes it possible to extend the retention time of electrical signals such as image signals, and In this state, the write interval can be set longer. This reduces the frequency of refresh operations. 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 mode: 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 Birefringe 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 using a vertical alignment (VA) mode The liquid crystal display device may be a transmission type liquid crystal display device. There are several types of vertical alignment modes, including: For example, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode In addition, a pixel can be divided into several regions (subpixels). The molecule is 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 antireflection member, For example, a polarizing substrate and a retardation substrate may be provided. Circular polarization by the substrate may be used. Also, backlight, sidelight, etc. may be used as the light source. It may be used.

[0135] The display method in the pixel area 142 is a progressive method or an interlace method. In addition, the color elements controlled by pixels when displaying in color are R Not limited to the three colors 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 be different for each dot of the color element. The present invention is not limited to color display devices, but may be used in monochrome display devices. can also be applied to.

[0136] In addition, a spacer 160 is formed below the second substrate 152. The distance between the first substrate 12 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 spacer, Any shape of spacer such as a spacer may be used.

[0137] The colored film 153 also functions as a so-called color filter. It is sufficient to use a material that is transparent to light in a specific wavelength range, such as organic materials containing dyes or pigments. 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 made of 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 light-shielding material.

[0139] In addition, 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 structure. It is also possible to adopt a configuration in which the above-mentioned is not provided.

[0140] The seal material 166 is a thermosetting resin or an ultraviolet-curing resin. In the sealing region of the sealant 166 shown in FIG. Between the second substrate 152 and the second substrate 152, a gate insulating film 106, a source electrode 110 and a drain electrode 1 An electrode 113, a first interlayer insulating film 114, and a second interlayer insulating film 115 are formed in the same process as in 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 portion of the pixel region. The end of the film is formed inside the driving circuit region. This prevents outgassing from the second interlayer insulating film from entering the transistor side, improving reliability. Further, 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 appropriately combined with structures shown in other embodiment modes or examples. It can be used.

[0143] (Embodiment 2) In this embodiment, a display device using an organic EL panel will be described as one embodiment of the display device. 3 and 4. Note that the same parts as those in the configuration shown in the first embodiment are shown in the same manner. The detailed description of these components 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 is provided on a first substrate 102, and A gate electrode is a driving circuit region adjacent to the outside of the pixel region 142 and supplies signals to the pixel region 142. A sealant is provided to surround 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 so as 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 by a sealant 166 and a second substrate 152 .

[0146] In this way, a part or the whole of the driving circuit including the transistors is 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. 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 is provided in contact with the gate electrode 106 and overlaps the gate electrode 104. A source electrode 110 and a drain electrode 111 are formed on the insulating film 106 and the semiconductor layer 108. 12 forms a first transistor 101.

[0149] In the pixel region 142, the first transistor 101, more specifically, the gate insulator An inorganic insulating film 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 insulating material and an organic insulating film on the first interlayer insulating film 114. A second interlayer insulating film 116 formed of an inorganic insulating material is formed on the second interlayer insulating film 116. The third interlayer insulating film 120 formed by the above, the second interlayer insulating film 116, and the third interlayer insulating film A partition wall 126 formed on the film 120, a third interlayer insulating film 120, and a partition wall 126 formed on the third interlayer insulating film 120 A pixel electrode 122 formed on the substrate, a light-emitting layer 128 formed on the pixel electrode 122, and a light-emitting layer 12 8 has an electrode 130 formed thereon.

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

[0151] Moreover, 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 filling material 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, and a gate insulating film 10 is formed on the gate electrode 104. 6, a semiconductor provided in contact with the gate insulating film 106 and at a position overlapping the gate electrode 104 A source electrode 110 formed on the semiconductor layer 108, a gate insulating film 106, and the semiconductor layer 108. and the drain electrode 112, the second transistor 103 and the third transistor A separator 105 is formed.

[0153] 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. has been formed.

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

[0155] By adopting such a configuration, moisture taken in from the outside or moisture inside the display device The moisture and gas 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. It is possible to suppress the above.

[0156] The second interlayer insulating film 116 made of an organic insulating material constitutes a display device. In order to reduce the unevenness of the transistor, an organic insulating material with high flatness is required. However, when the organic insulating material is heated, hydrogen, moisture, or organic components are converted 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 formed as the semiconductor layer 108. In order to use the second interlayer insulating film 116 made of an organic insulating material, gas is discharged to the outside. It is necessary to preferably emit the radiation. Note that the end of the third interlayer insulating film 120 is the driving circuit region. The structure formed on the inner side of the gate driver circuit section 140 is a structure in which the semiconductor layer 108 is made of an oxide. When the semiconductor layer 108 is made of 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 The same effect can be obtained with a transistor formed of a material other than silicon.

[0158] In addition, the third interlayer insulating film 120 formed on the second interlayer insulating film 116 is In this embodiment, 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. With this configuration, the third light emitting element 170 is This can prevent gases such as hydrogen and moisture from entering through the second interlayer insulating film 116.

[0159] However, in the second embodiment in which the third interlayer insulating film 120 is used for the gate driver circuit section 140, A 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 impurities are introduced into the oxide semiconductor film, and the characteristics of the transistor using the semiconductor layer 108 are The gender changes.

[0161] However, as shown in FIG. 4, the second transistor used in the gate driver circuit unit 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 making the structure capable of diffusing gas released from the second interlayer insulating film 116 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 disposed at the position where the semiconductor layer 108 overlaps. In this way, the insulating layer formed of the organic insulating material is preferably removed. Gas released from the second interlayer insulating film 116 enters the first transistor 101. It is possible to suppress the above.

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

[0164] The partition 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 side wall of the opening is a continuous curved It is preferable to form the inclined surface so that the inclined surface is formed with a certain rate.

[0165] The filler 172 may be an inert gas such as nitrogen or argon, or may be an ultraviolet curing resin. 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). 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 utilizes 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] In the organic EL element, a pair of electrodes (pixel electrodes 122) are connected by applying a voltage to the light emitting element. Electrons and holes are injected from the electrode 130 into the layer containing the light-emitting organic compound. When these 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-excitation type light-emitting element.

[0168] The light emitting element 170 has at least a pair of electrodes (pixel electrode 122 or It is sufficient that one of the electrodes (130) is transparent. The light emitted from the top surface is emitted from the surface on the first substrate 102 side. The light emitted from the bottom surface is emitted from the surface on the first substrate 102 side. A double-sided emission structure in which light is emitted from the first substrate 102 side and the side 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, in order to prevent oxygen, hydrogen, moisture, carbon dioxide, etc. from entering the light emitting element 170, the electrodes A protective film may be formed on the partition wall 126 and the insulating film 130. The protective film may be a silicon nitride film. A silicon oxynitride film or the like can be formed. The space sealed by the sealing material 166 and the filler 172 is provided and sealed. In this way, a highly airtight protective film with little 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 include

[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 (lambda / 4 plate, lambda / 2 plate), and color filters are appropriately installed. Also, the polarizing plate or the circular polarizing plate may be provided with an anti-reflection film. The convex surface can be used to diffuse reflected light and reduce glare with an anti-glare treatment.

[0171] The light-emitting layer 128 is made of a light-emitting material that converts triplet excitation energy into light emission. 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 material. A multi-layer structure (so-called tandem structure) and functional layers other than the light-emitting layer (hole injection layer, hole transport layer) layer, an electron transport layer, an electron injection layer, a charge generation layer, etc.).

[0172] The sealing material 166 may contain a 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 suppress 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. In the above embodiment, only the gate insulating film 106 is provided between the gate electrodes 152. However, 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 laminated 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 portion of the pixel region. The end of the film is formed inside the driving circuit region. This prevents outgassing from the second interlayer insulating film from entering the transistor side, improving reliability. Further, 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 appropriately combined with structures shown in other embodiment modes or examples. It can be used.

[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 having 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 the 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 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 driver 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] In addition, the photodiode element 4002 and the first transistor in the pixel region 5042 A first interlayer insulating film 4014, a second interlayer insulating film 4016, and a third interlayer insulating film 4017 are disposed on the sinter 4030. An interlayer insulating film 4020 of the second layer 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. With this configuration, the amount of the ions 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. The upper electrode is formed in one step, 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, n-type semiconductor films A pin-type diode or a Schottky diode, which includes a laminate of conductive films, may 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, a 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 layer 4082 is formed on the second substrate 4052 through the colored film 4085 and the liquid crystal layer 4096. 4002 is used to convert light incident on the diode element 4002 into an electrical signal. For example, the color 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. When the light is detected by the light guide element 4002, information about the detected 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] (Embodiment 4) 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 tablet terminals that can be folded in two. Figure 6(A) shows The tablet terminal is in an open state. The tablet terminal 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 changeover switch 8036, fastener 80 33 and an operation switch 8038.

[0193] The display device which is one embodiment of the present invention is applied to 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 display unit 8631a can be operated by touching all the operation keys. Keyboard buttons are displayed on the surface, it 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 is a touch panel. It can function as a.

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

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

[0198] FIG. 6A shows an example in which the display portion 8631b and the display portion 8631a have the same area. However, it is not particularly limited. The areas of the display portion 8631b and the display portion 8631a may be different. The display quality may be different. For example, one may display a higher resolution image than the other. The display panel may also include a display unit.

[0199] FIG. 6B shows the tablet terminal in a closed state. The tablet terminal is enclosed in a housing 86. 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 and 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, the case 8630 can be folded when not in use. Therefore, the display unit 8631a and the display unit 8631b can be protected. It is highly durable and reliable for long-term use.

[0201] In addition, the tablet terminals shown in Fig. 6(A) and Fig. 6(B) can display various information. Functions for displaying (still images, videos, text images, etc.), calendars, dates or times, etc. A function to display the information on the display, and a function to 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. A block diagram is shown and explained in FIG. 6(C). 5, a DC-DC converter 8636, a converter 8637, a switch SW1, In FIG. 6C, the switch SW2, the switch SW3, and the display unit 8631 are shown. Battery 8635, DCDC converter 8636, converter 8637, switch The switches SW1, SW2, and SW3 constitute a charge / discharge control circuit 86 shown in FIG. 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 DCDC converter 8636 to charge the 635. Next, switch SW1 is turned on, and the converter 8637 supplies the optimum voltage to the display 8631. When the display unit 8631 is not to be displayed, switch S Turn off switch W1 and turn on switch SW2 to charge the battery 8635.

[0205] Although the solar cell 8633 is shown as an example of a power generating means, the present invention is not limited thereto. Instead, they are replaced by other power generation methods such as piezoelectric elements and thermoelectric conversion elements. For example, a non-contact power transmission module that transmits and receives power wirelessly (non-contact) for charging is also available. It is also possible to use a configuration in which other charging means such as a power cord is combined with the charger.

[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. I will explain this in more detail.

[0208] FIG. 7A shows a portable information terminal. The portable information terminal shown in FIG. 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. The display device or / and the display device with the image sensor shown in the previous embodiment are applied to the device 03. It can be used.

[0209] FIG. 7B shows a display. The display shown in FIG. 7B is a housing 9310. and a display portion 9311. The display portion 9311 may be the display device described in the above embodiment. And / or a display device with an image sensor may be applied.

[0210] Fig. 7(C) shows a digital still camera. The digital still camera shown in Fig. 7(C) The mobile phone includes a housing 9320, a button 9321, a microphone 9322, and a display unit 9323. The display unit 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. EXAMPLES

[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 specimen was prepared by applying acrylic resin onto a glass substrate and heating it at 250℃ for 1 hour in a nitrogen gas atmosphere. The acrylic resin was heated for 1.5 μm after the heat treatment. was formed.

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

[0216] FIG. 8 shows the mass-to-charge ratio (M / z) at a substrate surface temperature of 250° C. The ion intensity of the released gas is shown in FIG. 8. 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, which is thought to be due to water, is 18 (H 2 O) gas and a mass-to-charge ratio of 28 (C 2 H 4 ), 44(C 3 H 8 ) and 56(C 4 H 8 ) gas was detected. Each fragment ion was detected.

[0217] Similarly, FIG. 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 intensities for mass-to-charge ratio 18 were 55°C to 100°C and 150°C to 160°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 ratios 28, 44, and 56 have peaks at temperatures between 150°C and 270°C. It was discovered that...

[0218] As described above, water from organic resins, hydrocarbons, and other substances that are harmful to the oxide semiconductor film are 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 and are released. It was suggested that the electrical characteristics of a transistor may be deteriorated if the

[0219] In addition, organic resins are treated with a film that does not transmit water, hydrocarbons, and other released gases (silicon nitride film, nitride When the material is covered with a film of silicon oxide or aluminum oxide, gas is released from the organic resin. This increases pressure on the membrane, which is impermeable to water, hydrocarbons, and other released gases, eventually causing the This can destroy the film that is impermeable to released gases such as hydrogen chloride, resulting in defective transistor shapes. was suggested. EXAMPLES

[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, 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 is a tungsten film, and the gate electrode is a pair of electrodes. The insulating film is a silicon nitride film and a silicon oxynitride film on the silicon nitride film, which are oxide semiconductors. The substrate is an In-Ga-Zn oxide film, the pair of electrodes are tungsten films, and the An aluminum film and a titanium film on an aluminum film were used, respectively.

[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 on the protective insulating film. A 200 nm thick nitride layer is applied to the acrylic resin to expose 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 200 nm thick acrylic resin is applied to cover the acrylic resin. A silicon nitride film is provided to 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 TE image. It shows the cross-sectional shape of the sample. The measurement was performed using Hitachi Ultra-thin Film Evaluation System HD-2300 manufactured by Hitachi High-Technologies Corporation. 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, It was found that a crack had occurred in the protective insulating film from the difference in area. Since the example sample and the comparative sample have roughly the same structure, the cross-sectional shape of the example sample is omitted.

[0225] Therefore, the sample has a structure in which the gas released from the acrylic resin is released to the outside of the sample. 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 sample, the gas released from the acrylic resin does not escape to the outside, but is a protective insulator. 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 measurements were performed using a transistor. Note that the Vg-Id characteristics were measured using a drain voltage ( The gate voltage (Vd) was set to 1V or 10V, and the gate voltage (Vg) was swept from -20V to 15V.

[0227] Figure 11 shows the Vg-Id characteristics of each sample. The Vg-Id characteristics of 20 transistors were measured in a uniform manner. 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 indicates the value at a drain voltage (Vd) of 10 V. In (B), it was difficult to calculate the field-effect mobility, so the calculation is omitted.

[0228] As shown in FIG. 11A, the transistor of the embodiment sample exhibits good switching characteristics. In addition, as shown in FIG. 11B, in the transistor of the comparative sample, It was found that no switching characteristics were obtained and that the device was always on.

[0229] By comparing with the embodiment sample, the switching characteristic failure of the comparative sample was attributed to the acrylic resin. This is because the gas emitted from the acrylic resin affected the transistor. The carrier density in the oxide semiconductor film increases due to the effect of gas released from the gate electrode, and the Therefore, it is presumed that the transistor could not be turned off.

[0230] In this embodiment, the organic resin is treated as a membrane (here, the thickness is 100 nm) that does not allow the passage of gases such as water and hydrocarbons. When the transistor is covered with a 200 nm thick silicon nitride film, the gas released from the organic resin In addition, the organic resin covering the capacitor, water, 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. It is clear that sexuality can be obtained. [Explanation of symbols]

[0231] 101 First transistor 102 First substrate 103 Second transistor 104 Gate electrode 105 Third Transistor 106 Gate insulating film 107 Capacitive 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 1st 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 Case 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 pixel portion having a first transistor; a driver circuit unit having a second transistor, a first conductive layer having an area in contact with a top surface of the substrate; a first insulating film having a region in contact with an upper surface of the first conductive layer; a first oxide semiconductor layer having a region in contact with an upper surface of the first insulating film and having a channel formation region of the first transistor; a second insulating film having a region located above the first oxide semiconductor layer; a second conductive layer having a region in contact with a top surface of the first oxide semiconductor layer and functioning as one of a source electrode and a drain electrode of the first transistor; a third conductive layer having a region in contact with a top surface of the first oxide semiconductor layer and functioning as the other of the source electrode and the drain electrode of the first transistor; a third insulating film having a region in contact with an upper surface of the second insulating film; a fourth conductive layer having a region in contact with an upper surface of the third insulating film; a fourth insulating film having a region in contact with an upper surface of the second conductive layer, a region in contact with an upper surface of the third conductive layer, a region in contact with an upper surface of the third insulating film, and a region in contact with an upper surface of the fourth conductive layer; a fifth conductive layer having a region in contact with an upper surface of the second conductive layer and a region in contact with an upper surface of the fourth insulating film, the fifth conductive layer functioning as a pixel electrode; a second oxide semiconductor layer having a region in contact with an upper surface of the first insulating film and having a channel formation region of the second transistor; the first conductive layer has a region overlapping with the first oxide semiconductor layer via the first insulating film; the second insulating film has a region overlapping the second oxide semiconductor layer, the third insulating film has a region overlapping the second oxide semiconductor layer, the fourth insulating film has a region overlapping with the first oxide semiconductor layer, the second oxide semiconductor layer has a region that does not overlap with the fourth insulating film, the fifth conductive layer has a region overlapping with the fourth conductive layer via the fourth insulating film, the first insulating film is a stack of a first layer having oxygen and silicon and a second layer having nitrogen and silicon; the second insulating film is a stack of a third layer having oxygen and silicon and a fourth layer having nitrogen and silicon; the third insulating film comprises an organic insulating material; The fourth insulating film comprises nitrogen and silicon.

2. A pixel portion having a first transistor; a driver circuit unit having a second transistor, a first conductive layer having an area in contact with a top surface of the substrate; a first insulating film having a region in contact with an upper surface of the first conductive layer; a first oxide semiconductor layer having a region in contact with an upper surface of the first insulating film and having a channel formation region of the first transistor; a second insulating film having a region located above the first oxide semiconductor layer; a second conductive layer having a region in contact with a top surface of the first oxide semiconductor layer and functioning as one of a source electrode and a drain electrode of the first transistor; a third conductive layer having a region in contact with a top surface of the first oxide semiconductor layer and functioning as the other of the source electrode and the drain electrode of the first transistor; a third insulating film having a region in contact with an upper surface of the second insulating film; a fourth conductive layer having a region in contact with an upper surface of the third insulating film; a fourth insulating film having a region in contact with an upper surface of the second conductive layer, a region in contact with an upper surface of the third conductive layer, a region in contact with an upper surface of the third insulating film, and a region in contact with an upper surface of the fourth conductive layer; a fifth conductive layer having a region in contact with an upper surface of the second conductive layer and a region in contact with an upper surface of the fourth insulating film, the fifth conductive layer functioning as a pixel electrode; a second oxide semiconductor layer having a region in contact with an upper surface of the first insulating film and having a channel formation region of the second transistor; the first conductive layer has a region overlapping with the first oxide semiconductor layer via the first insulating film; the second insulating film has a region overlapping the second oxide semiconductor layer, the third insulating film has a region overlapping the second oxide semiconductor layer, the fourth insulating film has a region overlapping with the first oxide semiconductor layer, the second oxide semiconductor layer has a region that does not overlap with the fourth insulating film, the fifth conductive layer has a region overlapping the second conductive layer via the fourth insulating film, the fifth conductive layer has a region overlapping with the fourth conductive layer via the fourth insulating film, the first insulating film is a stack of a first layer having oxygen and silicon and a second layer having nitrogen and silicon; the second insulating film is a stack of a third layer having oxygen and silicon and a fourth layer having nitrogen and silicon; the third insulating film comprises an organic insulating material; The fourth insulating film comprises nitrogen and silicon.

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