Display device

Abstract

To improve reliability of a display device by suppressing variation in characteristics of a transistor due to gas released from an organic insulating film.SOLUTION: The semiconductor device includes a transistor, an organic insulating film provided over the transistor in order to reduce unevenness due to the transistor, and a capacitor over the organic insulating film. The entire surface of an organic insulating film is not covered with components (a transparent conductive layer and an inorganic insulating film) of a capacitor, and a gas released from the organic insulating film can be released to the outside from part of an exposed upper surface of the organic insulating film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a display device and a manufacturing method thereof. [Background technology]

[0002] Liquid crystal display devices and electroluminescence flat panel displays, which are typified by light-emitting display devices that use EL (electroluminescence) The transistors used in many display devices are made of amorphous silicon formed on a glass substrate. The semiconductor includes silicon, monocrystalline silicon, or polycrystalline silicon.

[0003] Instead of the silicon semiconductor, oxides that exhibit semiconductor properties (hereinafter referred to as oxide semiconductors) Technology that uses this (to make it a semiconductor) in transistors is attracting attention.

[0004] For example, a transistor is fabricated using In-Ga-Zn oxide as an oxide semiconductor. A technology is disclosed in which the transistor is used as a switching element for pixels of a display device. (See Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in a transistor using an oxide semiconductor for a channel formation region, water is added to the oxide semiconductor. When impurities such as silicon and moisture enter the transistor, carriers are generated, and the electrical characteristics of the transistor change. It fluctuates.

[0007] Therefore, the transistors in the display device are made of an organic insulating film formed on the transistors. When unintentional impurities such as hydrogen and moisture enter the semiconductor layer of a transistor, The increase in carrier density in the semiconductor layer changes the transistor characteristics.

[0008] Furthermore, fluctuations in transistor characteristics can lead to a decrease in display quality and reliability. There is a problem of reduced sexuality.

[0009] In view of this, one embodiment of the present invention is to suppress fluctuations in electrical characteristics of a transistor used in a display device. Another object is to improve the reliability of a display device using a transistor. An object of the present invention is to suppress deterioration in display quality of a device and improve reliability. [Means for solving the problem]

[0010] A transistor and a layer formed on the transistor to reduce unevenness caused by the transistor. The capacitor element has an organic insulating film formed on the transparent conductive film and a capacitor element on the organic insulating film. By using a structure in which the entire organic insulating film is not covered with the insulating layer (electrical layer and inorganic insulating film), The gas released from the insulating film (also called released gas) escapes from above to the outside of the organic insulating film. The configuration is such that this is possible.

[0011] Therefore, a display device according to one embodiment of the present invention includes a transistor and a first insulating film covering the transistor. an inorganic insulating film, an organic insulating film on the first inorganic insulating film, and a first transparent conductive layer on the organic insulating film; a second inorganic insulating film on the first transparent conductive layer, and at least a first inorganic insulating film on the first transparent conductive layer through the second inorganic insulating film; and a second inorganic insulating film formed on the transparent conductive layer. a second transparent conductive layer electrically connected to the source electrode layer or the drain electrode layer of the transistor; a pixel portion including a liquid crystal layer on the second transparent conductive layer, and a second inorganic The insulating film has an edge in a region where it overlaps with the organic insulating film.

[0012] Since the end of the second inorganic insulating film is in the region where it overlaps with the organic insulating film, the organic insulating film , and has a region that does not overlap with the second inorganic insulating film. The insulating film does not overlap, and the released gas from the organic insulating film escapes upward from the area where the organic insulating film is exposed. It can be configured as follows.

[0013] In the above structure, the region where the organic insulating film and the second inorganic insulating film do not overlap is a transistor. The stator may be provided so as to overlap with the stator.

[0014] Furthermore, in a display device according to one embodiment of the present invention, a transistor and a first inorganic insulating film covering the transistor are provided. an insulating film, an organic insulating film on the first inorganic insulating film, a first transparent conductive layer on the organic insulating film, and a first a second inorganic insulating film on the transparent conductive layer, and at least a first transparent insulating film on the second inorganic insulating film The conductive layer is provided on the organic insulating film and the first inorganic insulating film. a second transparent conductive layer electrically connected to the source electrode layer or the drain electrode layer of the transistor; A surface having a liquid crystal layer on the second transparent conductive layer, the liquid crystal layer and the organic insulating film being at least partially in contact with each other. It is a display device.

[0015] In the above structure, the liquid crystal layer and the organic insulating film are in contact with each other in the region where they overlap with the transistor. It may be possible.

[0016] Alternatively, the transistor may have a channel formed in an oxide semiconductor layer. .

[0017] The first inorganic insulating film and the second inorganic insulating film are silicon nitride films or silicon nitride oxide films. It is preferable that the film is a membrane.

[0018] The organic insulating film is preferably a film containing acrylic. This makes it easy to obtain a flat surface.

[0019] The difference in refractive index between the second inorganic insulating film and the first transparent conductive layer or the second transparent conductive layer is the refractive index of the transparent conductive layer or the second transparent conductive layer is 10% or less, preferably 5% or less. In addition, it is preferable that a layer having a refractive index that is equal to the refractive index of the transparent conductive layer and the organic insulating layer is provided between the organic insulating layer and the first transparent conductive layer. It is advisable to form a film having a refractive index between the refractive indices of the films.

[0020] The liquid crystal layer has its orientation controlled in response to the electric field between the first transparent conductive layer and the second transparent conductive layer. It is a display device.

[0021] In addition, it is preferable that at least a portion of the first inorganic insulating film and the second inorganic insulating film are in contact with each other. [Effects of the Invention]

[0022] According to one embodiment of the present invention, fluctuations in electrical characteristics of a transistor used in a display device can be suppressed. In addition, the reliability of the display device using the transistor can be improved. This can suppress deterioration in performance and improve reliability. [Brief explanation of the drawings]

[0023] [Figure 1] 1A and 1B are a top view and a cross-sectional view of a display device according to one embodiment of the present invention. [Figure 2] FIG. 1 is a top view of a display device according to one embodiment of the present invention. [Figure 3] FIG. 10 is a diagram showing the ion intensity of emitted gas at each mass-to-charge ratio. [Figure 4] FIG. 10 is a graph showing the ion intensity at each mass-to-charge ratio relative to the substrate surface temperature. [Figure 5] 1A and 1B are a top view and a cross-sectional view of a display device according to one embodiment of the present invention. [Figure 6] 1A and 1B are a circuit diagram and a cross-sectional view illustrating an example of an image sensor according to one embodiment of the present invention. [Figure 7] FIG. 10 illustrates an example of a tablet terminal according to one embodiment of the present invention. [Figure 8] 1A to 1C illustrate examples of electronic devices according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and it is understood by those skilled in the art that various modifications can be made to the modes and details. It will be easily understood. Furthermore, the present invention should not be construed as being limited to the description of the following embodiments. It is not something that can be done.

[0025] In the embodiments described below, the same reference numerals are used in common between different drawings. It should be noted that the thickness, width, relative position, etc. of the components shown in the drawings, i.e., layers and regions, may differ. In order to clarify the description of the embodiments, the positional relationships may be exaggerated. There is a match.

[0026] In this specification, the term "above" means that the positional relationship of a component is "directly above." For example, the expression "gate electrode layer on an insulating film" is not limited to the insulating film. This does not exclude the inclusion of other components between the film and the gate electrode layer. is.

[0027] In addition, in this specification, the terms "electrode layer" and "wiring layer" refer to the functional components of these elements. For example, the "electrode layer" is used as part of the "wiring layer." Furthermore, the terms "electrode layer" and "wiring layer" may be used interchangeably. This also includes cases where multiple "electrode layers" or "wiring layers" are formed integrally.

[0028] Also, the functions of "source" and "drain" may differ depending on whether transistors with different polarities are used or not. However, they may be swapped when the direction of current changes during circuit operation. In this specification, the terms "source" and "drain" are used interchangeably. It is assumed that this is possible.

[0029] In this specification, "electrically connected" means "something that has some kind of electrical effect." This includes cases where the device is connected via a " is not subject to any particular restrictions as long as it enables the transmission and reception of electrical signals between connected objects.

[0030] For example, "something that has some kind of electrical effect" includes electrodes and wiring.

[0031] (Embodiment 1) In this embodiment, a display device according to one embodiment of the present invention will be described with reference to the drawings. 1 is a top view of a display device according to an embodiment of the present invention;

[0032] FIG. 2A is a top view of a display device according to one embodiment of the present invention. A sealing material 1001 is provided so as to surround a pixel portion 1000 provided on a plate 101. 2A, the first substrate 101 is sealed by the second substrate 102. A separately prepared substrate is placed in an area different from the area surrounded by the upper sealing material 1001. A scanning line driver circuit 1004 formed of a single crystal semiconductor film or a polycrystalline semiconductor film on the A signal line driver circuit 1003 is mounted on the substrate. Various signals and potentials given to the line driver circuit 1004 or the pixel portion 1000 are transmitted through the FPC (F (flexible printed circuit) 1018a, 1018b It is being done.

[0033] The method of connecting the separately formed drive circuit is not particularly limited, and may be ip On Glass) method, wire bonding method, or TAB (Tape A The C This is an example in which a signal line driver circuit 1003 and a scanning line driver circuit 1004 are implemented by the OG method.

[0034] The display device also includes a panel in which a display element is sealed, and a controller for the panel. and modules in which ICs, etc., including the above are mounted.

[0035] In this specification, the term "display device" refers to an image display device, a display device, or an optical device. Also refers to a source (including lighting equipment) to which a connector, such as FPC or TCP, is attached. a module with a printed wiring board at the end of the TCP, or a display element All modules with ICs (integrated circuits) directly mounted on the chip using the COG method are included in the display device. This shall be done.

[0036] Note that the structure of the display device described in this embodiment mode is not limited to the above. The pixel portion 1000 and the scanning line driving circuit 1004 are provided on the first substrate 101. A sealing material 1001 may be provided between the pixel section 1000 and the scanning line driver. The second substrate 102 may be provided on the circuit 1004. The scanning line driver circuit 1004 is a circuit formed by the first substrate 101, the sealing material 1001, and the second substrate 10. 2, and is sealed together with the display element.

[0037] The sealing material 1001 is typically a visible light curable, ultraviolet curable or thermosetting resin. It is preferable to use acrylic resin, epoxy resin, amine resin, etc. In addition, a photopolymerization initiator (typically ultraviolet light), a heat curing agent, a filler, a coloring agent, etc. can be used. It may also contain a coupling agent.

[0038] In FIGS. 2B and 2C, the first substrate 101 is surrounded by a sealing material 1001. A single crystal semiconductor film or a polycrystalline semiconductor film is formed on a separately prepared substrate in a region different from the region where the semiconductor film is formed. A signal line driver circuit 1003 formed of a thin film is mounted on the substrate. a scanning line driver circuit 1003, a scanning line driver circuit 1004, or various signals provided to the pixel portion 1000; Signals and potentials are supplied from the FPC 1018.

[0039] In FIG. 2B, a signal line driver circuit 1003 is formed separately and is In FIG. 2C, the signal line driver circuit 1003 is an FP 1 shows an example of the display device mounted on a display device C1018 according to one embodiment of the present invention. The device is not limited to this configuration. A scanning line driving circuit may be formed separately and mounted, or a signal line Only a part of the driving circuit or a part of the scanning line driving circuit may be separately formed and mounted.

[0040] FIG. 1 illustrates one pixel included in a pixel portion 1000 of a display device according to one embodiment of the present invention. FIG. 1(A) shows a top view of a part of a pixel included in the pixel portion 1000, and FIG. 1(B) shows a top view of the pixel included in FIG. 1(A). 1 shows a cross-sectional view taken along the dashed line AB shown in FIG.

[0041] A pixel portion included in a display device according to one embodiment of the present invention includes a transistor provided over a first substrate 101. The first inorganic insulating film 114 (the inorganic insulating film 113 and the inorganic insulating film 114) on the transistor 150 is The organic insulating film 115 is laminated on the first inorganic insulating film 114, and the organic insulating film 117 is laminated on the first inorganic insulating film 114. The capacitance element 170 on the film 117, and the liquid crystal layer 125 on the organic insulating film 117 and the capacitance element 170 a second substrate 102 on the liquid crystal layer 125; and a transparent conductive layer 103 provided on the second substrate 102. The capacitance element 170 includes a transparent conductive layer 121, a transparent conductive layer 123, and A second inorganic insulating film 119 is further sandwiched therebetween.

[0042] As can be seen from FIG. 1B, the second inorganic insulating film 119 overlaps with the organic insulating film 117. Therefore, the second inorganic insulating film 119 and the organic insulating film 117 overlap each other. The organic insulating film 117 has an unconvoluted region, and the organic insulating film 117 is exposed from the region where the organic insulating film 117 is exposed. In particular, the second inorganic insulating film 119 is a transistor. The insulating film 117 is not provided in the region overlapping with the second inorganic insulating film 150. The region where the film 119 does not overlap and the organic insulating film 117 is exposed overlaps with the transistor 150. The organic insulating film 117 is made up of a second inorganic insulating film 119, a transparent conductive layer 121, and a transparent It does not overlap with the transparent conductive layer 123 and has an exposed area.

[0043] In the display device according to one embodiment of the present invention, a second inorganic insulating film 119 is provided over an organic insulating film 117. The upper surface of the organic insulating film 117 is not covered with the insulating film 117, and a part of the upper surface of the organic insulating film 117 is exposed. The upper surface has a region where gas is emitted to the outside. This prevents the gas from entering the transistor side, and the characteristics of the transistor 150 are less likely to fluctuate. Therefore, a highly reliable display device can be obtained in which the deterioration of display quality is suppressed.

[0044] The transistor 150 includes a gate electrode layer 105 on a first substrate 101 and a gate electrode layer 10 a gate insulating layer 107 covering the gate insulating layer 107; a semiconductor layer 109 on the gate insulating layer 107; 09, and a source electrode layer 111a and a drain electrode layer 111b in contact with the gate insulating film 109.

[0045] The semiconductor layer of the transistor 150 is made of a silicon-based semiconductor (amorphous silicon, polycrystalline silicon, etc.). Silicon, an oxide semiconductor (zinc oxide, indium oxide, etc.), or the like can be used. In this embodiment, when an oxide semiconductor is used as a suitable semiconductor for the semiconductor layer 109, This section explains the case.

[0046] On the transistor 150, the inorganic insulating film 113 and the inorganic insulating film 114 are formed. The first inorganic insulating film 114 is not limited to this configuration, and may be formed as needed. The insulating film may be provided as a single layer or a stacked layer depending on the function to be achieved.

[0047] The inorganic insulating film 113 provided on the transistor 150 is made of a material such as silicon oxide or gallium oxide. , aluminum oxide, silicon oxynitride, silicon nitride oxide, hafnium oxide, or oxide An oxide insulating layer such as tantalum oxide can be used. Alternatively, it may be formed and used in a laminated structure of two or more layers.

[0048] Here, silicon oxynitride is a material whose composition contains more oxygen than nitrogen. For example, oxygen is 50 atomic % or more and 70 atomic % or less, and nitrogen is 0.5 atomic % or less. % or more and 15 atomic % or less, and silicon is contained in the range of 25 atomic % or more and 35 atomic % or less. However, the above range is based on the Rutherford backscattering method (RBS). Backscattering Spectrometry and hydrogen forward scattering spectrometry (H When measured using FS (Hydrogen Forward Scattering) The content ratio of the constituent elements is set so that the total does not exceed 100 atomic percent. Take.

[0049] The inorganic insulating film 115 formed on the inorganic insulating film 113 prevents impurities such as hydrogen from entering the semiconductor layer 109. the oxide semiconductor layer. This layer has the function of preventing oxygen, hydrogen, water, etc. from being released. By providing the inorganic insulating film 115 having a blocking effect, oxygen from the semiconductor layer 109 is prevented from escaping to the outside. and the penetration of impurities such as hydrogen into the organic insulating film 117 and the semiconductor layer 109 from the outside. This can be prevented.

[0050] Examples of insulating films that have a blocking effect against oxygen, hydrogen, water, etc. include aluminum oxide and Aluminum nitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride Examples include thorium, hafnium oxide, and hafnium oxynitride.

[0051] A planarization insulating layer is formed on the inorganic insulating film 115 to reduce unevenness caused by the transistor 150. The planarization insulating layer is provided with an organic insulating film 117 that functions as a This is provided to prevent alignment defects in the liquid crystal layer and improve display quality. By using an organic insulating film as the insulating layer, a flat surface can be easily obtained. .

[0052] The organic insulating film 117 may be made of, for example, acrylic resin, polyimide, or benzocyclobutene-based Heat-resistant organic materials such as resin, polyamide, and epoxy resin can be used. The insulating film may be formed by laminating a plurality of insulating films made of these materials.

[0053] A capacitor element 170 is formed on the organic insulating film 117. a transparent conductive layer 121 on the insulating film 117; and a second inorganic insulating film 119 on the transparent conductive layer 121. and a transparent conductive layer 123 on the second inorganic insulating film 119. The layer 123 is formed in the openings provided in the first inorganic insulating film 114 and the organic insulating film 117. It is in contact with the drain electrode layer 111 b of the transistor 150 .

[0054] The capacitance element 170 on the organic insulating film 117 is formed by the transparent conductive layer 121, the second inorganic insulating film 119, and the and the transparent conductive layer 123. That is, the transparent conductive layer 121 is The transparent conductive layer 123 functions as one electrode of the capacitor element 170. The second inorganic insulating film 119 functions as a dielectric of the capacitor element 170 .

[0055] The magnitude of the storage capacitance of the capacitor 170 is determined by taking into consideration the leakage current of the transistor 150, etc. The capacitance is set to be able to hold charge for a predetermined period of time. The off-state current of a transistor having an oxide semiconductor film may be taken into consideration. As a result, the capacitance of the liquid crystal in each pixel is 1 / 3 or less, preferably 1 / 5 or less. It is sufficient to provide a storage capacitor having a size of .times. ...

[0056] A transistor including an oxide semiconductor layer has a low current value in an off state (off-state current value). Therefore, the retention time of electrical signals such as image signals can be extended. When the power is on, the write interval can be set longer. The oxide semiconductor layer can be reduced, which has the effect of reducing power consumption. The field-effect mobility of transistors using this material can be controlled to a high level, enabling high-speed operation. It is possible.

[0057] The transparent conductive layer 121 and the transparent conductive layer 123 are made of a material that is transparent to visible light. Examples of light-transmitting materials include indium oxide, indium tin oxide, and indium tin oxide. zinc oxide, zinc oxide, zinc oxide doped with gallium, graphene, etc. Here, "transparent" means that the material has the ability to transmit visible light, and the material is transparent when visible light is transmitted. If the light is scattered, it is called transparent. It is called transparent. It is sufficient to transmit at least a part of the wavelength range of visible light. Even if a part of the wavelength range is reflected by the layer, it is still called a transparent conductive layer. By forming the 0 from a transparent material, the aperture ratio can be increased.

[0058] Here, the outgassing of acrylic resin, which is a typical organic resin used for the organic insulating film 117, will be explained. The results of the survey are shown below.

[0059] The sample was prepared by applying acrylic resin to a glass substrate and heating it at 250°C for 1 hour in a nitrogen gas atmosphere. The acrylic resin was heated to a thickness of 1.5 μm after the heat treatment. Formed.

[0060] The prepared samples were analyzed by thermal desorption spectroscopy (TDS). The released gas was measured by on-line spectroscopy analysis.

[0061] FIG. 3 shows the radiation at each mass-to-charge ratio (also called M / z) when the substrate surface temperature is 250°C. Figure 3 shows the ion intensity of the outgoing gas. From the sample, the mass-to-charge ratio is 18, which is thought to be due to water. (H2O) gas and hydrocarbon-derived gas with mass-to-charge ratios of 28 (C2H4) and 44 (C The gases 3H8) and 56 (C4H8) were detected. Each fragment ion was detected.

[0062] Figure 4 shows the ion intensity for each mass-to-charge ratio (18, 28, 44, and 56) versus the substrate surface temperature. When the substrate surface temperature is in the range of 55℃ to 270℃, the mass that is thought to be caused by water The ionic strength of a charge ratio of 18 is between 55°C and 100°C and between 150°C and 270°C. On the other hand, it was found that the mass-charge peaks were in the range of 1000 to 1000 m / s, which are thought to be due to hydrocarbons. The ionic strengths of the samples with charge ratios of 28, 44, and 56 have peaks between 150°C and 270°C. It was found that...

[0063] As mentioned above, impurities for oxide semiconductors, such as water and hydrocarbons, are released from organic resins. In particular, water is released even at relatively low temperatures between 55°C and 100°C. That is, it was found that impurities originating from the organic resin were absorbed into the oxide semiconductor film even at a relatively low temperature. It was suggested that the temperature reaches a critical temperature, which deteriorates the electrical characteristics of the transistor.

[0064] In addition, organic resins are used as films that do not allow the passage of released gases such as water and hydrocarbons (silicon nitride films, nitriding acid films, etc.). When the surface is covered with a film such as silicon dioxide or aluminum oxide, gas is released from the organic resin. This increases the pressure on the membrane, which is impermeable to released gases such as water and hydrocarbons, and ultimately The film that does not allow released gases such as hydrogen to pass through may be destroyed, resulting in a defective transistor shape. It was suggested that this is the case.

[0065] The second inorganic insulating film 119 sandwiched between the transparent conductive layer 121 and the transparent conductive layer 123 is The second inorganic insulating film 119 can be formed using the same material as the inorganic insulating film 114. To function as a dielectric of the capacitance element 170, the capacitance element 170 must have a required dielectric constant. For example, a nitride film having a higher relative dielectric constant than a silicon oxide film can be used. By using a silicon film, the capacitance per electrode area can be increased. .

[0066] In addition, the refractive index of the transparent conductive layer 121 or the transparent conductive layer 123 and the refractive index of the second inorganic insulating film 119 are The difference in refractive index between the transparent conductive layer 121 and the transparent conductive layer 123 is preferably 10% or less of the refractive index of the transparent conductive layer 121 and the transparent conductive layer 123. The second inorganic insulating film 119 and the transparent conductive layer 12 are preferably an insulating layer having a thickness of 5% or less. When the difference in refractive index between the second inorganic insulating film and the transparent conductive layer 1 or the transparent conductive layer 123 is small, The total reflection of light occurs at the interface between the second inorganic insulating film 119 and the transparent conductive layer 123. is suppressed, and light loss can be reduced.

[0067] Similarly, total reflection at the interface between the organic insulating film 117 and the transparent conductive layer 121 is prevented. Therefore, a layer having a refractive index different from that of the organic insulating film 117 and the transparent conductive layer 121 is formed between the organic insulating film 117 and the transparent conductive layer 121. An insulating film may be formed between the conductive layers 121. As a result, the refractive index changes stepwise from the organic insulating film 117 to the transparent conductive layer 121. It may also be possible to use the following.

[0068] For example, the refractive index of acrylic resin, which is commonly used as an organic insulating film, is approximately 1.49. The refractive index of indium tin oxide, which is generally used as the transparent conductive layer 121, is 2.0. Therefore, the insulating film provided between the organic insulating film 117 and the transparent conductive layer 121 is An insulating film having a refractive index of 1.5 or more and 1.9 or less, preferably 1.6 or more and 1.7 or less, is used. Alternatively, a laminated structure of these may be used.

[0069] Refractive index of indium zinc oxide used as the transparent conductive layer 121 and the transparent conductive layer 123 The refractive index is 2.0. Materials with a refractive index similar to that of indium zinc oxide are A silicon nitride film having a refractive index of about 2.03 can be suitably used for the second inorganic insulating film 119. .

[0070] The second inorganic insulating film 119 has a capacitance formed by the transparent conductive layer 121 and the transparent conductive layer 123. It is sufficient that the capacitor element 170 is formed and provided to function as a dielectric of the capacitor element 170. The second inorganic insulating film 119 is formed by absorbing gas emitted from the organic insulating film 117. When an opaque film (such as a silicon nitride film or a silicon nitride oxide film) is used, the second When the inorganic insulating film 119 is formed so as to cover the entire surface of the organic insulating film 117, the organic insulating film 117 The gas emitted from the diffuses toward the transistor 150, and the characteristics of the transistor 150 are affected. It may be subject to change.

[0071] Alternatively, the released gas does not escape from the organic insulating film 117, and the organic insulating film 117 is not released from the first inorganic insulating film. The pressure between the film 114 and the second inorganic insulating film 119 increases, and the second inorganic insulating film 119 is destroyed. The occurrence of shape defects may cause the second inorganic insulating film 1 19, there may be formed areas with low film density or areas where the film itself disappears. By forming such a region, impurities such as hydrogen enter the semiconductor layer 109. This may cause the characteristics of the transistor 150 to fluctuate.

[0072] Therefore, the second inorganic insulating film 119 prevents the gas emitted from the organic insulating film 117 from flowing upward (to the It is preferable to have a structure in which the current passes through to the opposite side of the transistor 150. The end of the inorganic insulating film 119 is preferably in a region overlapping with the organic insulating film 117. The edge of the insulating film 119 is in the region overlapping with the organic insulating film 117, 17 is entirely covered with the inorganic insulating film 113 and the second inorganic insulating film 119. Instead, the organic insulating film 117 has an exposed portion through which released gas can escape.

[0073] Here, the exposed portion of the organic insulating film 117 refers to at least the second insulating film 117. The organic insulating film 117 has an exposed portion. By doing so, the released gas from the organic insulating film 117 can be released upward, This can prevent impurities from entering the resistor 150.

[0074] The region where the organic insulating film 117 is exposed may be provided anywhere in the pixel section 1000. The gas released from the organic insulating film 117 contains impurities such as hydrogen. It is provided so that gas emitted from the organic insulating film 117 does not enter the transistor 150 side. It is preferable that

[0075] For example, in the region of the organic insulating film 117 that overlaps with the transistor 150, at least one For example, the organic insulating film 117 may have an exposed region in the transistor 150. In the region overlapping with a part of the source electrode layer 111a or the drain electrode layer 111b, Alternatively, in the region where the organic insulating film 117 and the semiconductor layer 109 overlap, Therefore, at least a part of the organic insulating film 117 may be exposed.

[0076] In addition, the gas released from the organic insulating film 117 is The organic insulating film 117 is formed so that the light is emitted from the surface opposite to the surface facing the semiconductor layer 109. An exposed region of the organic insulating film 117 may be formed on the surface not facing the semiconductor layer 109. In addition, the surface of the organic insulating film 117 facing the semiconductor layer 109 is larger than the surface facing the semiconductor layer 109. The surface exposed on the insulating layer 124 is a region in contact with the liquid crystal layer 125 in FIG. 1(B). The more areas that can be used, the better.

[0077] In addition, the organic insulating film 117 and the sealing material 1001 (not shown) are configured not to come into contact with each other. The insulating film 117 is formed so that the released gas is released from the side surface (the surface facing the sealing material 1001). , an insulating layer, a transparent conductive layer, etc. are not formed on the side surface of the organic insulating film 117. The organic insulating film 117 may have an area where the end of the organic insulating film 117 is exposed to the second inorganic insulating film. It may be configured to be covered with a membrane 119.

[0078] The display device described in this embodiment mode is a display device in which light emitted from an organic insulating film provided over a transistor is To prevent gas from entering the transistor, an exposed area of ​​the organic insulating film is provided on the transistor. The exposed portion is formed by a region that does not overlap with the inorganic insulating film formed on the organic insulating film. Since the inorganic insulating film is not formed in contact with the exposed area, the Therefore, the gases released from the organic insulating film can escape from the exposed area. Gases containing impurities such as fluorine and fluorine may enter the oxide semiconductor layer, causing fluctuations in the characteristics of the transistor. This can prevent the above problem, and the display device can have high display quality and high reliability. .

[0079] The transistor 150 includes a gate electrode layer 105 over a first substrate 101 .

[0080] The first substrate 101 must have at least sufficient heat resistance to withstand subsequent heat treatment. For example, glass such as barium borosilicate glass or aluminoborosilicate glass is required. Substrates such as glass substrates, ceramic substrates, quartz substrates, and sapphire substrates can be used. .

[0081] The first substrate 101 is previously subjected to heat treatment at a temperature lower than the distortion point of the first substrate 101. It is desirable to shrink (also called thermal shrinkage) the first substrate 101 in advance. As a result, the first substrate 101 is heated during the manufacturing process of the display device. Therefore, for example, the amount of shrinkage that occurs during the exposure process can be reduced. Furthermore, the heat treatment can prevent the surface of the first substrate 101 from being displaced. It can remove moisture and organic matter adhering to the surface.

[0082] In addition, single crystal semiconductor substrates such as silicon and silicon carbide, polycrystalline semiconductor substrates, silicon gate It is also possible to use a compound semiconductor substrate such as aluminum on which an insulating layer is formed. do.

[0083] The gate electrode layer 105 may be made of aluminum, chromium, copper, tantalum, titanium, molybdenum, or titanium. or an alloy containing the above-mentioned metal elements, or It can be formed by using an alloy or the like that combines metal elements such as manganese, zinc, etc. Alternatively, one or more metal elements selected from the group consisting of ruthenium, arsenic, and chromium may be used. The electrode layer 105 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 stacked on top of a titanium film, and a tungsten film stacked on top of a titanium nitride film Two-layer structure: a tungsten film is laminated on a tantalum nitride film or a tungsten nitride film Structure: titanium film, aluminum film stacked on the titanium film, titanium film on top of that There are also three-layer structures that form aluminium, titanium, tantalum, tungsten, etc. , molybdenum, chromium, neodymium, scandium, or a combination of elements A combined alloy film or nitride film may also be used.

[0084] In particular, in order to reduce the resistance of the gate electrode layer 105 and ensure heat resistance, for example, Al Titanium, molybdenum, copper, or other low-resistivity metal film is applied to one or both of the upper and lower sides. High melting point metal films such as buten and tungsten or their metal nitride films (titanium nitride film, nitride The insulating layer 11 may have a structure in which a layer including a molybdenum nitride film, a tungsten nitride film, and a molybdenum nitride film is laminated.

[0085] The gate electrode layer 105 may be formed of indium tin oxide or indium containing tungsten oxide. oxide, indium zinc oxide with tungsten oxide, indium oxide with titanium oxide oxide, indium tin oxide containing titanium oxide, indium zinc oxide, silicon oxide A light-transmitting conductive material such as indium tin oxide may also be used. Alternatively, the light-transmitting conductive material and the metal element may be laminated together.

[0086] In addition, an In-Ga-Zn oxynitride is formed between the gate electrode layer 105 and the gate insulating layer 107. Semiconductor film, In-Sn oxynitride semiconductor film, In-Ga oxynitride semiconductor film, In-Zn Sn-based oxynitride semiconductor film, Sn-based oxynitride semiconductor film, In-based oxynitride semiconductor film, metal nitride film ( These films may have a resistance of 5 eV or more, preferably 5.5 eV or more. Since the work function is greater than or equal to the electron affinity of the oxide semiconductor, The threshold voltage of the transistor using the conductor can be shifted to the positive side, 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 an oxide semiconductor film, specifically, 7 atomic %. The above-mentioned In-Ga-Zn-based oxynitride semiconductor film is used.

[0087] The gate insulating layer 107 is made of, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. silicon oxide, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn based metals An oxide or the like may be used, and the layer may be a laminated layer or a single layer.

[0088] In addition, since the gate insulating layer 107 is in contact with the oxide semiconductor, the hydrogen concentration is reduced. In addition to preventing hydrogen from entering the oxide semiconductor, it also supplies oxygen to oxygen vacancies in the oxide semiconductor. For example, the membrane that supplies oxygen is preferably a membrane that can It is preferable that oxygen is present in an amount exceeding the stoichiometric content at least in the bulk. Preferably, for example, when a silicon oxide film is used as the gate insulating layer 107, SiO 2+α (where α>0).

[0089] When an insulating film contains oxygen in an amount exceeding the stoichiometric ratio, some of the oxygen is removed by heating. For this reason, an insulating film from which part of the oxygen is released by heating is used as the gate insulating layer 107. By providing the oxide semiconductor, oxygen is introduced into the oxide semiconductor, and oxygen vacancies in the oxide semiconductor are compensated for. It is possible to do this.

[0090] When a film from which oxygen is released by heating is used for the gate insulating layer 107, the oxide semiconductor film and It is possible to reduce the density of interface states at the interface of the gate insulating layer 107, and the electrical characteristics are improved. In addition, the gate insulating layer 107 can be formed of an oxide film. By providing an insulating film having a blocking effect on hydrogen, water, and the like, It is possible to prevent oxygen from diffusing to the outside and hydrogen, water, etc. from entering the oxide semiconductor film from the outside. As an insulating film having a blocking effect against oxygen, hydrogen, water, etc., aluminum oxide is Aluminum, aluminum oxide nitride, gallium oxide, gallium oxide nitride, yttrium oxide, Examples include yttrium nitride, hafnium oxide, and hafnium oxynitride.

[0091] The gate insulating layer 107 is made of hafnium silicate (HfSiO x ), nitrogen added Hafnium silicate (HfSi x O y N z ), nitrogen-doped hafnium aluminium Laminate (HfAl x O y N z ), hafnium oxide, yttrium oxide, etc. The use of k-materials can reduce gate leakage of transistors.

[0092] The thickness of the gate insulating layer 107 is 5 nm or more and 400 nm or less, and more preferably 10 nm or more. It is preferable to set the thickness to 300 nm or less, and more preferably to set the thickness to 50 nm or more and 250 nm or less.

[0093] The gate insulating layer 107 has a laminated structure, and is formed by using a PECVD apparatus from the gate electrode layer side. and a first gate insulating layer having an effect of preventing the diffusion of metal components contained in the gate electrode layer 105. A 50 nm silicon nitride layer was used as the gate insulator, and a 30 nm silicon dioxide layer was used as the second gate insulator for better dielectric breakdown resistance. 0nm silicon nitride layer and a 50nm silicon nitride layer as a third gate insulating layer with high hydrogen blocking properties. and a fourth gate insulating layer, which has the effect of reducing the density of interface states. A 50 nm thick silicon oxynitride layer is stacked on top of the silicon oxide layer.

[0094] In addition, when an oxide semiconductor is used for the semiconductor layer 109, similarly to the gate insulating layer 107, an inorganic The insulating film 113 may be formed using an oxide insulator from which oxygen is released by heating. After the inorganic insulating film 113 is formed on the substrate, heat treatment is performed to convert oxygen into the oxide semiconductor layer. By adding oxygen, oxygen vacancies in the oxide semiconductor layer can be compensated for. Therefore, the amount of oxygen vacancies contained in the oxide semiconductor layer can be reduced.

[0095] The oxide semiconductor used for the semiconductor layer 109 is at least indium (In) or It preferably contains zinc (Zn), or it preferably contains both In and Zn. In addition, in order to reduce variations in the electrical characteristics of transistors using the oxide semiconductor, In addition, it is preferable to have a stabilizer.

[0096] Stabilizers include gallium (Ga), tin (Sn), hafnium (Hf), and aluminum. Aluminum (Al) or zirconium (Zr). Also, other stabilizers The lanthanides are lanthanum (La), cerium (Ce), and praseodymium (P r), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium ( Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium Er, Thulium, Ytterbium, Lutetium, etc. It may have one or more of the stabilizers described above.

[0097] For example, oxide semiconductors include indium oxide, tin oxide, zinc oxide, and In-Zn oxide. , Sn-Zn oxide, Al-Zn oxide, Zn-Mg oxide, Sn-Mg oxide, In- Mg oxide, In-Ga oxide, In-Ga-Zn oxide, In-Al-Zn oxide, I n-Sn-Zn oxide, Sn-Ga-Zn oxide, Al-Ga-Zn oxide, Sn-Al -Zn oxide, In-Hf-Zn oxide, In-La-Zn oxide, In-Ce-Zn oxide oxide, In-Pr-Zn oxide, In-Nd-Zn oxide, In-Sm-Zn oxide, I n-Eu-Zn oxide, In-Gd-Zn oxide, In-Tb-Zn oxide, In-Dy -Zn oxide, In-Ho-Zn oxide, In-Er-Zn oxide, In-Tm-Zn oxide oxide, In-Yb-Zn oxide, In-Lu-Zn ​​oxide, In-Sn-Ga-Zn oxide In-Hf-Ga-Zn oxide, In-Al-Ga-Zn oxide, In-Sn-Al -Zn oxide, In-Sn-Hf-Zn oxide, In-Hf-Al-Zn oxide It is possible.

[0098] Here, for example, In-Ga-Zn oxide is a material containing In, Ga, and Zn as its main components. The ratio of In, Ga, and Zn does not matter. Metal elements other than Zn may also be included.

[0099] In addition, as an oxide semiconductor, InMO3(ZnO) m (m>0 and m is not an integer) It is also possible to use a material represented by the formula: where M is selected from Ga, Fe, Mn, and Co. It refers to one or more metal elements. In addition, as an oxide semiconductor, In2SnO5 (ZnO) nA material expressed as (n>0 and n is an integer) may be used.

[0100] For example, In:Ga:Zn=1:1:1, In:Ga:Zn=2:2:1, or In In-Ga-Zn oxide with an atomic ratio of Ga:Zn=3:1:2 and oxides of similar compositions Alternatively, In:Sn:Zn=1:1:1, In:Sn:Zn In-Sn-Zn oxide with an atomic ratio of In:Sn:Zn=2:1:3 or In:Sn:Zn=2:1:5 It is advisable to use an oxide of the same material or a material having a similar composition.

[0101] However, the semiconductor properties and electrical properties required (field effect mobility, threshold voltage, etc.) are not limited to these. It is sufficient to use a material with an appropriate composition depending on the required semiconductor device (such as the minimum voltage, the variation, etc.). To obtain conductor properties, the carrier density, impurity concentration, defect density, number of metal elements and oxygen atoms, etc. It is preferable to set the ratio, interatomic distance (bond distance), density, etc. appropriately.

[0102] For example, high mobility can be obtained relatively easily with In-Sn-Zn oxide. In the case of In-Ga-Zn oxide, the mobility can be increased by reducing the defect density in the bulk. It is possible.

[0103] In addition, the oxide semiconductor film used for the semiconductor layer 109 has an energy gap of 2 eV or more. An oxide semiconductor having a valence of preferably 2.5 eV or more, more preferably 3 eV or more is used. In this way, by using an oxide semiconductor with a wide energy gap, The off-state current can be reduced.

[0104] The structure of the oxide semiconductor film will be described below.

[0105] In this specification, "parallel" means that two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, it includes the case where the angle is between -5° and 5°. refers to the state in which two straight lines are arranged at an angle of 80° or more and 100° or less. This includes cases where the angle is between 85° and 95°.

[0106] In addition, in this specification, when the crystal is a trigonal or rhombohedral crystal, it is expressed as a hexagonal crystal system. .

[0107] Oxide semiconductor films are roughly classified into non-single-crystal oxide semiconductor films and single-crystal oxide semiconductor films. The single-crystal oxide semiconductor film is called CAAC-OS (C Axis Aligned Crystal Polycrystalline oxide semiconductor film The oxide semiconductor film includes a microcrystalline oxide semiconductor film, an amorphous oxide semiconductor film, and the like.

[0108] A CAAC-OS film having a crystalline portion can be suitably used for the semiconductor layer 109. Cut.

[0109] The CAAC-OS film is one of the oxide semiconductor films that has multiple crystal parts. The crystal part is so large that it fits inside a cube with a side length of less than 100 nm. The crystals contained in the S film are cubic with sides of less than 10 nm, 5 nm, or 3 nm. This also includes cases where the size fits within the

[0110] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a crystalline microscope, clear boundaries between the crystals, i.e., crystal boundaries, are clearly visible. It is not possible to confirm the grain boundary. It can be said that the AC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0111] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). ) It can be confirmed that the metal atoms are arranged in layers in the crystalline part. Each layer has a surface on which the CAAC-OS film is formed (also referred to as a surface on which the CAAC-OS film is formed) or an uneven surface on which the CAAC-OS film is formed. The shape reflects this and is aligned parallel to the surface on which the CAAC-OS film is formed or the top surface.

[0112] On the other hand, the CAAC-OS film was observed by TEM from a direction approximately perpendicular to the sample surface (planar TEM). When observed, it was found that the metal atoms were arranged in triangular or hexagonal shapes in the crystals. However, there is no regularity in the arrangement of metal atoms between different crystal parts. stomach.

[0113] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It turns out that there are.

[0114] X-ray diffraction (XRD) was performed on the CAAC-OS film. For example, a CAAC-OS film with InGaZnO4 crystals was found by structural analysis using the device. In the out-of-plane analysis, a peak was observed at a diffraction angle (2θ) of approximately 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. This indicates that the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis is approximately aligned on the surface on which the film is formed or on the upper surface. It can be seen that it is oriented in a substantially vertical direction.

[0115] On the other hand, in-pl X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In the analysis by the ane method, a peak may appear at 2θ around 56°. This is attributed to the (110) plane of the InGaZnO4 crystal. In the case of a semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is set as the axis (φ axis). When the sample is rotated and analyzed (φ scan), the crystal plane equivalent to the (110) plane is In contrast, in the case of the CAAC-OS film, 2θ is set to 5 Even when the φ is fixed at around 6° and scanned, no clear peak appears.

[0116] From the above, it is concluded that the a-axis and b-axis orientations are inconsistent between different crystal regions in the CAAC-OS film. Although it is regular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface to be formed or the upper surface. Therefore, the layered arrangement confirmed by the cross-sectional TEM observation mentioned above is consistent with the above. Each layer of aligned metal atoms is a plane parallel to the ab plane of the crystal.

[0117] The crystalline part is formed when the CAAC-OS film is formed or when a crystallization process such as a heat treatment is performed. As described above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed or the surface on which the CAAC-OS film is formed. The orientation of the CAAC-OS film is parallel to the normal vector of the top surface. When the shape is changed by etching, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is formed. Or it may not be parallel to the normal vector of the upper surface.

[0118] The crystallinity of the CAAC-OS film may not be uniform. When the crystal part of the CAAC-OS film is formed by crystal growth from the vicinity of the top surface, The area near the surface may have a higher degree of crystallinity than the area near the surface to be formed. When impurities are added to a C-OS film, the crystallinity of the region where the impurities are added changes, resulting in partial In some cases, regions of different crystallinity may be formed.

[0119] In addition, the out-of-plane method of CAAC-OS film with InGaZnO4 crystals In the analysis by , in addition to the peak at 2θ around 31°, a peak also appeared at 2θ around 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in part of the CAAC-OS film. The CAAC-OS film contains crystals that do not have a 2θ of around 31°. It is preferable that the peak is exhibited at 2θ of around 36° and that the peak is not exhibited at 2θ of around 36°.

[0120] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. These are elements other than the main components of the oxide semiconductor film, such as silicon and transition metal elements. The elements that bond to oxygen more strongly than the metal elements that constitute the oxide semiconductor film, such as fluorine, are oxidized. By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide have an atomic radius (or molecular radius) is large, and when it is contained inside the oxide semiconductor film, The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement and cause a decrease in crystallinity. Objects can act as carrier traps or carrier sources.

[0121] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in the semiconductor film can become carrier traps or trap hydrogen, It can be a source of carrier generation.

[0122] Low impurity concentration and low defect level density (low oxygen vacancies) are called high purity intrinsic or The term "substantially highly purified intrinsic" refers to a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film. Since there are fewer carrier generation sources, the carrier density can be reduced. A transistor using an oxide semiconductor film has electrical characteristics such as a negative threshold voltage ( It is also called marion.) It is rare for it to become high purity genuine or substantially high purity genuine. The oxide semiconductor film has few carrier traps. A transistor using such a material has little fluctuation in electrical characteristics and is highly reliable. Note that it takes a long time for charges trapped in the carrier traps in the oxide semiconductor film to be released. The time between the charges is long and the charge may behave as if it is a fixed charge. However, a transistor using an oxide semiconductor film with a high density of defect states has unstable electrical characteristics. There are cases where this happens.

[0123] In addition, transistors using CAAC-OS films show improved electrical characteristics when irradiated with visible light or ultraviolet light. The fluctuation is small.

[0124] Next, a microcrystalline oxide semiconductor film that can be used for the semiconductor layer 109 will be described.

[0125] In the microcrystalline oxide semiconductor film, crystal parts can be clearly seen in the TEM image. The crystal part contained in the microcrystalline oxide semiconductor film may have a size of 1 nm or more and 100 nm or less. , or 1 nm to 10 nm in size. Nanocrystals (nc) are microcrystals of 1 nm or less and 3 nm or less. The oxide semiconductor film having nc-OS (nanocrystalline Oxide Semiconductor Film) The nc-OS film is called a TE film. In the M observation image, the grain boundaries may not be clearly visible.

[0126] The nc-OS film is a microscopic region (e.g., a region of 1 nm to 10 nm, especially a region of 1 nm or more). The nc-OS film has a periodic atomic arrangement in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystal parts. Therefore, no orientation is observed throughout the film. Therefore, depending on the analytical method, the nc-OS film may be indistinguishable from an amorphous oxide semiconductor film. For example, an XRD apparatus using X-rays with a diameter larger than that of the crystals is used for nc-OS films. When structural analysis is performed using the out-of-plane method, the crystal plane is shown. In addition, the probe diameter ( Electron beam diffraction (also called selected area electron beam diffraction) using an electron beam of, for example, 50 nm or more On the other hand, for the nc-OS film, the crystalline The probe diameter is close to the size of the crystal part or smaller than the crystal part (for example, 1 nm to 30 nm). When electron beam diffraction using a sagittal beam (also called nanobeam electron diffraction) is performed, spots are observed. Furthermore, when nanobeam electron diffraction is performed on the nc-OS film, circular patterns (ripples) are observed. In addition, nanobeams on the nc-OS film may be observed. When electron diffraction is performed, multiple spots may be observed within the ring-shaped region.

[0127] The nc-OS film is an oxide semiconductor film with higher order than an amorphous oxide semiconductor film. Therefore, the nc-OS film has a lower density of defect states than the amorphous oxide semiconductor film. In the nc-OS film, there is no regularity in the crystal orientation between different crystal parts. The S film has a higher defect state density than the CAAC-OS film.

[0128] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, or a CA The AC-OS film may be a laminated film having two or more kinds of films.

[0129] In addition, in an oxide semiconductor having a crystalline part such as a CAAC-OS film, defects in the bulk are reduced. If the surface flatness is improved, the transfer rate can be reduced to more than that of an amorphous oxide semiconductor. To improve the surface flatness, an oxide semiconductor is formed on the flat surface. It is preferable to form

[0130] However, since the transistor 150 described in this embodiment is a bottom-gate transistor, Below the nitride semiconductor film, there are a substrate 101, a gate electrode layer 105, and a gate insulating layer 107. Therefore, in order to obtain the above-mentioned flat surface, the gate electrode layer 105 and the gate insulating layer 107 are After forming the layer, chemical mechanical polishing (CMP) A flattening process such as polishing may be performed.

[0131] The oxide semiconductor film may have a structure in which a plurality of oxide semiconductor films are stacked. The oxide semiconductor film is a stack of a first oxide semiconductor film and a second oxide semiconductor film. The oxide semiconductor film and the second oxide semiconductor film may be made of metal oxides having different compositions. For example, a metal oxide film is used for the first oxide semiconductor film, and a first oxide semiconductor film is used for the second oxide semiconductor film. A metal oxide different from the compound semiconductor film may be used.

[0132] In addition, the first oxide semiconductor film and the second oxide semiconductor film are made to contain the same constituent elements, and the composition of both films is For example, the atomic ratio of the first oxide semiconductor film may be set to In:Ga:Zn=1. :1:1, and the atomic ratio of the second 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 the second oxide semiconductor film may be In:Ga:Zn=2:1:3.

[0133] At this time, the first oxide semiconductor film and the second oxide semiconductor film that are closer to the gate electrode layer 105 are The In content and Ga content of the oxide semiconductor film on the inner side (channel side) may be set to In>Ga. In addition, the In and Ga of the oxide semiconductor film on the side farther from the gate electrode layer 105 (the back channel side) It is preferable that the content of In≦Ga be satisfied.

[0134] In addition, the oxide semiconductor film has a three-layer structure, and the first oxide semiconductor film to the third oxide semiconductor film The constituent elements may be the same, but the compositions may be different. The atomic ratio of the conductor 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. :Zn=1:1:1 may also be used.

[0135] 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, in which Ga:Zn=1:3:2, has a higher atomic number of In than Ga and Zn. an oxide semiconductor film having a large ratio, typically a second oxide semiconductor film, and In comparison with an oxide semiconductor film having the same In atomic ratio, typically a third oxide semiconductor film, Highly related.

[0136] In addition, since the constituent elements of the first to third oxide semiconductor films are the same, The first oxide semiconductor film has a small number of trap states at the interface with the second oxide semiconductor film. Therefore, by using the oxide semiconductor film with the above structure, it is possible to prevent deterioration of the transistor over time and withstand stress testing. This can reduce the amount of variation in threshold voltage due to experimentation.

[0137] In oxide semiconductors, the s orbitals of heavy metals mainly contribute to carrier conduction, and the In content By increasing the amount of In, more s orbitals overlap, resulting in an oxide with a composition of In>Ga. In oxides with a composition of In≦Ga have higher mobility. The formation energy of oxygen vacancies is larger than that of Ga, making it difficult for oxygen vacancies to occur. The oxide having the composition In>Ga has stable characteristics compared to the oxide having the composition In>Ga.

[0138] An oxide semiconductor with a composition of In>Ga is applied to the channel side, and In≦ By using an oxide semiconductor with a Ga composition, the field-effect mobility and signal This makes it possible to further increase reliability.

[0139] In addition, when the semiconductor layer 109 has a stacked structure, the first oxide semiconductor film, the second oxide semiconductor film, the third oxide semiconductor film, and the third oxide semiconductor film are stacked. Oxide semiconductor films with different crystallinity may be used as the conductor film. Conductor film, polycrystalline oxide semiconductor film, amorphous oxide semiconductor film, or CAAC-OS film is used as appropriate. The first to third oxide semiconductor films may be formed by combining the first to third oxide semiconductor films. When an amorphous oxide semiconductor film is used in either one of the above cases, the internal stress of the oxide semiconductor film and the external stress can be reduced. This reduces the stress from the transistors, reducing the variation in their characteristics and improving the reliability of the transistors. It is possible to further improve the performance.

[0140] The thickness of the oxide semiconductor film is preferably 1 nm to 100 nm, more preferably 1 nm to 50 nm. m or less, more preferably 1 nm or more and 30 nm or less, and even more preferably 3 nm or more and 20 nm or less It is preferable to set it to below.

[0141] In oxide semiconductor films, secondary ion mass spectrometry (SIMS) Alkali metal or alkali metal obtained by mass spectrometry The concentration of earth metals is 1×10 18 atoms / cm 3 or less, more preferably 2 × 10 1 6 atoms / cm 3 The alkali metals and alkaline earth metals are preferably When the oxide semiconductor is bonded to the oxide semiconductor, carriers may be generated, which may reduce the off-state current of the transistor. This is because it causes an increase.

[0142] In the oxide semiconductor film, the hydrogen concentration obtained by secondary ion mass spectrometry was 5×10 1 8 atoms / cm 3 Less than 1 x 10 18 atoms / cm 3 The following is more preferred: Or 5 x 10 17 atoms / cm 3 or less, more preferably 1 × 10 16 atoms / cm 3 It is preferable to do the following:

[0143] Hydrogen contained in the oxide semiconductor film reacts with oxygen that is bonded to metal atoms to form water. A defect is formed in the lattice where oxygen is removed (or in the part where oxygen is removed). When some of the hydrogen bonds with oxygen, electrons are generated as carriers. Therefore, by significantly reducing impurities including hydrogen in the film formation process of the oxide semiconductor film, The hydrogen concentration in the oxide semiconductor film can be reduced. By removing the oxide semiconductor film and using the purified oxide semiconductor film as a channel formation region, the threshold voltage It is possible to reduce the negative voltage shift and The leakage current (typically, off-state current, etc.) in the semiconductor device is reduced to several yA / μm to several zA / μm. This allows the electrical characteristics of the transistor to be improved.

[0144] Oxide semiconductor films can be formed by sputtering, coating, pulsed laser deposition, and laser ablation. It is formed by the ion method or the like.

[0145] When an oxide semiconductor film is formed by a sputtering method, a power supply for generating plasma is required. The device may be an RF power supply, an AC power supply, a DC power supply, or the like, as appropriate.

[0146] The sputtering gas is a mixture of a rare gas (typically argon), oxygen, or a mixture of a rare gas and oxygen. In the case of a mixed gas of rare gas and oxygen, the ratio of oxygen to rare gas is It is preferable to increase the gas ratio.

[0147] The target may be appropriately selected depending on the composition of the oxide semiconductor film to be formed.

[0148] When the CAAC-OS film is formed, for example, a polycrystalline oxide semiconductor target is used. When ions collide with the target, the target The crystalline region included in the target is cleaved from the ab plane, forming a flat plate with a plane parallel to the ab plane. Or, it may peel off as pellet-shaped sputtering particles. The sputtered particles reach the substrate while maintaining their crystalline state, resulting in the formation of a CAAC- An OS film can be formed.

[0149] In addition, the following conditions are preferably applied to form the CAAC-OS film.

[0150] By reducing the amount of impurities mixed in during film formation, it is possible to prevent the crystal state from being destroyed by impurities. For example, the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be In addition, the impurity concentration in the deposition gas can be reduced. A deposition gas at a temperature of -80°C or lower, preferably -100°C or lower, is used.

[0151] In addition, by increasing the substrate heating temperature during film formation, the migration of sputtered particles after they reach the substrate is reduced. 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 200°C and 500°C. When a plate-shaped sputtering particle reaches the substrate, migration occurs on the substrate, The flat surface of the sputtered particle adheres to the substrate.

[0152] In addition, increasing the oxygen ratio in the deposition gas and optimizing the power reduces plasma damage during deposition. The oxygen ratio in the deposition gas is preferably 30% by volume or more, and more preferably 100% by volume or more. The product is %.

[0153] As an example of the target, an In-Ga-Zn oxide target will be described below.

[0154] InO X powder, GaO Y Powder and ZnO Z The powders are mixed in a specified number of moles and then pressurized. By heat treatment at a temperature between 1000℃ and 1500℃, polycrystalline In-Ga -Zn oxide target, where X, Y and Z are any positive numbers. The molar ratio of a certain amount is, for example, InO X powder, GaO Y Powder and ZnO Z Powder, 2:2 :1, 8:4:3, 3:1:1, 1:1:1, 4:2:3 or 3:1:2. The type of powder and the molar ratio of the powder to be mixed can be changed depending on the target to be produced. Just do that.

[0155] After the oxide semiconductor film is formed, heat treatment is performed to dehydrogenate or The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate distortion point, preferably The temperature is preferably 250°C or higher and 450°C or lower, and more preferably 300°C or higher and 450°C or lower.

[0156] Heat treatment is carried out using rare gases such as helium, neon, argon, xenon, krypton, or nitrogen. The heating is carried out in an inert gas atmosphere containing oxygen. Alternatively, the heating is carried out in an inert gas atmosphere, followed by heating in an oxygen atmosphere. It should be noted that the inert atmosphere and oxygen atmosphere do not contain hydrogen, water, etc. The treatment time is preferably 3 minutes to 24 hours.

[0157] After the oxide semiconductor film is formed, heat treatment is performed, whereby the hydrogen concentration in the oxide semiconductor film is reduced. degrees to 5 x 10 18 atoms / cm 3 Less than 1 x 10 18 atoms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 or less, more preferably 1 × 10 16 atoms / cm 3 It can be as follows:

[0158] Note that in the case where an oxide insulating layer is used as the gate insulating layer 107, an oxide semiconductor The oxide semiconductor film is heated in a state where the conductive film is provided, thereby supplying oxygen to the oxide semiconductor film. As a result, oxygen defects in the oxide semiconductor film can be reduced, and the semiconductor characteristics can be improved. By performing a heating process while at least a part of the oxide semiconductor film and the oxide insulating layer are in contact with each other, In this way, oxygen may be supplied to the oxide semiconductor film.

[0159] The source electrode layer and the drain electrode layer on the semiconductor layer 109 are the gate electrode layer 1 It can be produced using the same materials and methods as those used in 05.

[0160] In this embodiment, the source electrode layer 111a and the drain electrode layer 111b are formed by sputtering. A 50 nm titanium film, a 400 nm aluminum film, and a 100 nm After stacking the titanium films in order, a resist mask is applied to the titanium film by photolithography. A resist mask is formed, and the titanium film, the aluminum film, and the titanium film are formed using the resist mask. A portion of the laminate film including the silicon film is selectively removed.

[0161] The liquid crystal material used for the liquid crystal layer 125 on the capacitance element 170 is a thermotropic liquid crystal, a low Molecular liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. These liquid crystal materials (liquid crystal compositions) can be in a cholesteric phase, a smectic phase, or a smectic phase depending on the conditions. The phases shown in Figure 1 are ectic, cubic, chiral nematic, and isotropic. Although not shown, the liquid crystal layer 125 has an insulating layer that functions as an alignment film sandwiching these material layers. Controlling the insulating film and the distance (cell gap) between the transparent conductive layer 123 and the transparent conductive layer 127 The alignment film may be made of acrylic resin, polyimide resin, or the like. Heat-resistant resins such as benzocyclobutene resins, polyamide resins, and epoxy resins Organic materials that can be used can be used.

[0162] Alternatively, a liquid crystal composition that exhibits a blue phase without using an alignment film may be used. When the temperature of cholesteric liquid crystal is increased, it changes from the cholesteric phase to the isotropic phase. The blue phase is a phase that appears just before the transition. In order to widen the temperature range in which the blue phase appears, In addition, a polymerizable monomer and a polymerization initiator are added to the liquid crystal composition that exhibits the blue phase, and a highly polymerizable The liquid crystal layer can be formed by carrying out a molecular stabilization treatment. The composition has a short response time, is optically isotropic, does not require alignment treatment, and is not dependent on viewing angle. In addition, since there is no need to provide an alignment film, rubbing treatment is also unnecessary. It is possible to prevent electrostatic breakdown caused by the processing, and the liquid crystal display device during the manufacturing process Therefore, the productivity of the liquid crystal display device can be improved. A transistor using an oxide semiconductor film is susceptible to static electricity. Therefore, the electrical characteristics of the oxide semiconductor film may fluctuate significantly and deviate from the designed range. A liquid crystal composition exhibiting a blue phase is used in a liquid crystal display device having a transistor using is more effective.

[0163] The specific resistance of the liquid crystal material is 1×10 9 Ω·cm or more, preferably 1×10 11 Ω·cm or more, and more preferably 1×10 12 Ω·cm or more. The resistivity values ​​in this document are those measured at 20°C.

[0164] The liquid crystal layer 125 can be driven in a TN (Twisted Nematic) mode, an I PS (In-Plane-Switching) mode, FFS (Fringe Field Switching) mode ld Switching) mode, ASM(Axially Symmetric a ligned Micro-cell) mode, OCB (Optical Compen) Sated Birefringence mode, FLC (Ferrerolectri c Liquid Crystal) mode, AFLC (AntiFerrerolect ric Liquid Crystal) mode can be used.

[0165] Furthermore, normally black type liquid crystal display devices, for example, those employing vertical alignment (VA) mode The liquid crystal display device may be a transmission type. For example, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode , ASV (Advanced Super View) mode, etc. can be used. It can also be applied to VA type liquid crystal display devices. VA type liquid crystal display devices are: It is a type of method for controlling the alignment of liquid crystal molecules in a liquid crystal display panel. VA type liquid crystal display devices are When no voltage is applied, the liquid crystal molecules are oriented perpendicular to the panel surface. In addition, a pixel is divided into several regions (subpixels), each of which is oriented in a different direction. This is called multi-domain or multi-domain design, which is designed to knock down molecules. The following method can be used.

[0166] In addition, in display devices, black matrices (light-shielding layers), polarizing members, phase difference members, reflecting members, Optical members (optical substrates) such as a protection member are provided as appropriate. For example, a polarizing substrate and a retardation substrate are provided as appropriate. Alternatively, a backlight or a sidelight may be used as the light source. It's fine.

[0167] In addition, the display method in the pixel section uses the progressive method, interlace method, etc. In addition, the color elements controlled by pixels when displaying colors are RGB (R is It is not limited to the three colors (red, green, and blue). For example, RGBW (W stands for white). , or RGB plus one or more colors such as yellow, cyan, magenta, etc. The size of the display area may be different for each dot of the color element. is not limited to color display devices, but also applies to monochrome display devices. It is also possible.

[0168] In FIG. 1, the orientation of the liquid crystal layer 125 is controlled by the transparent conductive layer 123 and the transparent conductive layer 127. Therefore, in FIG. 1, the transparent conductive layer 123 functions as a pixel electrode. The transparent conductive layer 127 functions as a common electrode. The alignment of the liquid crystal layer 125 is controlled in accordance with the electric field between the transparent conductive layer 121 and the transparent conductive layer 123. 5, the transparent conductive layer 121 functions as a common electrode, The transparent conductive layer 123 functions as a pixel electrode.

[0169] Note that the display device described in this embodiment is not limited to the configuration shown in FIG. 1 and may have the configuration shown in FIG. 5, for example. That's fine.

[0170] FIG. 5 shows part of a pixel included in a display device of another embodiment of the present invention. 5A is a top view of a part of a pixel included in a display device of another embodiment of the present invention, and FIG. 5B is a top view of a part of a pixel included in a display device of another embodiment of the present invention. 5 shows a cross-sectional view taken along the dashed line CD in (A). The same reference numerals are used for the same components, and detailed explanations will be omitted.

[0171] 5 is different from FIG. 2 in that a part of the capacitor 180 is used as a dielectric. The point where the second inorganic insulating film 129 overlaps with the drain electrode layer 111b of the transistor 150 By adopting such a configuration, the second inorganic insulating film 129 and the inorganic insulating film The second inorganic insulating film 129 and the inorganic insulating film 115 contact each other, and the organic insulating film 11 7, and the gas emitted from the organic insulating film 117 can be diffused to the transistor 150 side. can be suppressed.

[0172] The display device described in this embodiment mode is a display device in which light emitted from an organic insulating film provided over a transistor is To prevent gas from entering the transistor side, the exposed organic insulating film on the opposite side of the transistor is The exposed portion is formed by a region that does not overlap with the inorganic insulating film formed on the organic insulating film. Since the inorganic insulating film is not formed in contact with the exposed portion, the organic insulating film emits light. The gas emitted from the organic insulating film can escape through the exposed area. Gas containing impurities such as hydrogen enters the oxide semiconductor layer, causing changes in the characteristics of the transistor. This makes it possible to prevent the display device from moving, thereby providing a display device with high display quality and high reliability. can.

[0173] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiments. is.

[0174] (Embodiment 2) 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.

[0175] FIG. 6(A) shows an example of a display device with an image sensor. 1 is an equivalent circuit showing one pixel of a display device with a filter.

[0176] The photodiode element 4002 has one electrode connected to a reset signal line 4058 and the other electrode connected to a reset signal line 4058. The electrode is electrically connected to the gate electrode of transistor 4040. 0 means that either the source or drain electrode is connected to the power supply potential (VDD), and The other drain electrode is connected to one of the source and drain electrodes of the transistor 4056. The transistor 4056 has a gate electrode electrically connected to a gate selection line 4057. The other of the source electrode and the drain electrode is electrically connected to the output signal line 4071. .

[0177] The transistor 4030 is a transistor for pixel switching, and the source voltage One of the source or drain electrodes is connected to a video signal line 4059, The other end is electrically connected to the capacitor element 4032 and the liquid crystal element 4034. The gate electrode of the transistor 4030 is electrically connected to a gate line 4036 .

[0178] Note that the transistor 4030 and the capacitor 4032 are the same as those in the display device described in Embodiment 1. A similar structure can be applied.

[0179] FIG. 6B is a cross-sectional view showing a part of one pixel of the display device with an image sensor. In this example, a photodiode element 4002 and a transistor 4001 are disposed on a substrate 4001. 30 is provided on the pixel section 5042. An inorganic insulating film 4020 is formed on the substrate 4010 to be used as a dielectric for the capacitor 4032. The organic insulating film 4020 has an opening in a part of the area overlapping with the transistor 4030. The film 4016 has an exposed portion on which no inorganic insulating film is formed.

[0180] With this configuration, the gas released from the organic insulating film 4016 is This prevents the light from entering the 030 side, making it possible to provide a highly reliable display device.

[0181] The organic insulating film 40 is formed on the photodiode element 4002 and the transistor 4030. 16 is provided on the organic insulating film 4016 as a dielectric of the capacitance element 4032. The inorganic insulating film 4020 is formed on the transistor 40. 30 and 31. It is not provided on a part of the area overlapping with 30.

[0182] By adopting such a structure, the diffusion of gas emitted from the organic insulating film to the transistor side is prevented. This can suppress the noise and provide a highly reliable display device.

[0183] The photodiode element 4002 is connected to the source electrode and the drain electrode of the transistor 4030. The lower electrode is formed in the same process as the pixel electrode of the liquid crystal element 4034. The upper electrode is formed as a pair of electrodes, and a diode is provided between the pair of electrodes. be.

[0184] The diode that can be used for the photodiode element 4002 is a p-type semiconductor. pn-type diodes including stacks of p-type semiconductor films, i-type semiconductor films, and n-type semiconductor films A pin diode or a Schottky diode, which includes a laminate of conductive films, can be used. .

[0185] 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 ... A facing substrate 4052 and the like are provided.

[0186] In this embodiment, unlike the first embodiment, the first alignment film 402 sandwiching the liquid crystal layer 4096 The first alignment film 4024 and the second alignment film 4084 are arranged in the same manner. The film 4084 may be made of acrylic resin, polyimide, benzocyclobutene resin, polyamide, etc. Heat-resistant organic materials such as acrylic resin and epoxy resin can be used. The first alignment film 4024 is formed in contact with the organic insulating film 4016. It is preferable that the membrane is permeable to the gas released from 16 .

[0187] In this embodiment, the liquid crystal layer 4096 is formed by a transparent conductive layer and a The orientation of the liquid crystal layer 4096 is controlled by the voltage applied to the counter electrode 4088. There are.

[0188] 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 photodiode element 4052 is connected to the surface of the counter substrate 4052 via the liquid crystal layer 4096 and the like. 1. The configuration in which the light incident on the optical fiber 102 is converted into an electrical signal is shown as an example, but the present invention is not limited to this. Also, a colored film or the like may be provided on the opposing substrate side.

[0189] The photodiode element 4002 shown in this embodiment is the same as the photodiode element 400 When light is incident on the photodiode 2, a current flows between the pair of electrodes. The light is detected by the light-emitting diode element 4002, and information about the object can be read.

[0190] The display device with an image sensor described in this embodiment mode is a display device, and manufacturing methods such as transistor manufacturing are also possible. By sharing the manufacturing process for the device and the image sensor, productivity can be improved. However, the display device described in the above embodiment and the image sensor described in this embodiment may be different. Specifically, in the display device shown in the above embodiment, Alternatively, an image sensor may be fabricated on the second substrate.

[0191] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiment modes. It is Noh.

[0192] (Embodiment 3) In this embodiment, an example of a tablet terminal according to one embodiment of the present invention will be described.

[0193] Figures 7(A) and 7(B) show tablet terminals that can be folded in half. The tablet device is in an open state. The tablet device is made up of a housing 8630 and a housing 863 The display unit 8631a, the display unit 8631b, and the display mode changeover switch 8631b are provided in the display unit 8631. 034, power switch 8035, power saving mode switch 8036, fastener 803 3 and an operation switch 8038.

[0194] The display unit 8631a can be partially or entirely used as a touch panel. For example, the entire surface of the display unit 8631a can be touched to input information. keyboard buttons are displayed on the display unit 8631b, which functions as a touch panel. It may also be used as a surface.

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

[0196] In addition, the touch panel area of ​​the display unit 8631a and the touch panel area of ​​the display unit 8631b You can also use touch input 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 switch between black and white and color display. Switch 8036 responds to external light detected by a light sensor built into the tablet device. The display brightness can be optimized. Note that the tablet device does not only have a light sensor. Alternatively, other detection devices such as a gyro or acceleration sensor that can detect tilt may be provided.

[0198] FIG. 7A shows an example in which the display portion 8631b and the display portion 8631a have the same area. However, there is no particular limitation. The areas of the display portions 8631b and 8631a may be different. The display quality may be different. For example, one may display a higher resolution image than the other. It may also be a display panel.

[0199] FIG. 7B shows the tablet terminal in a closed state. 0, a solar cell 8633 and a charge / discharge control circuit 8634 provided in a housing 8630, 7B shows a battery 863 as an example of the charge / discharge control circuit 8634. 5 shows a configuration including a DC-DC converter 8636.

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

[0201] In addition, the tablet terminals shown in Fig. 7(A) and Fig. 7(B) can also display various information ( Functions that display still images, videos, text images, etc., calendars, dates, or times, etc. Functions to display on the display, touch input operation or editing of information displayed on the display It has functions such as input and output, and the ability to control processing using various software (programs). It is possible.

[0202] The tablet device uses the power obtained by the solar cell 8633 to operate the tablet device. Alternatively, the power can be stored in the battery 8635. Note that the solar cells 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. There are advantages to this.

[0203] The configuration and operation of the charge / discharge control circuit 8634 shown in FIG. 7B will be described with reference to FIG. 7C. A block diagram is shown and explained. In FIG. 7(C), a solar cell 8633 and a battery 8635 , DC / DC converter 8636, converter 8637, switch SW1, and switch 7C shows the switch SW2, the switch SW3, and the display unit 8631. , Battery 8635, DCDC converter 8636, Converter 8637, Switch S The switches SW1, SW2, and SW3 are connected to the charge / discharge control circuit 863 shown in FIG. Corresponds to 4.

[0204] When power is generated by the solar cell 8633, the power generated by the solar cell is transferred to the battery 86 The voltage is stepped up or down by the DC / DC converter 8636 to provide the voltage needed to charge the 35. Next, the switch SW1 is turned on, and the converter 8637 supplies the optimum voltage to the display 8631. When the display on the display unit 8631 is not displayed, the switch SW Turn off switch 1 and turn on switch SW2 to charge battery 8635.

[0205] Although the solar cell 8633 is shown as an example of the power generation means, it is not particularly limited, and a piezoelectric Even if other power generation methods such as piezoelectric elements or thermoelectric conversion elements (Peltier elements) are used instead, For example, a non-contact power transmission module that transmits and receives power wirelessly (contactlessly) for charging. It is also possible to use a configuration in which other charging means are combined, such as a power cable.

[0206] The display portion 8631a and the display portion 8631b included in the tablet terminal shown in this embodiment include: By applying the display device described in the above embodiment, reliability can be improved. .

[0207] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiments. is.

[0208] (Fourth embodiment) In this embodiment, an example of an electronic device equipped with the display device or the like shown in the above embodiment will be described. I will explain.

[0209] 8A shows a portable information terminal. The portable information terminal shown in FIG. 8A includes a housing 9300. , a button 9301, a microphone 9302, a display unit 9303, and a speaker 930 The display unit 930 is equipped with a display 9304 and a camera 9305, and functions as a mobile phone. The display device and / or the image sensor shown in the above embodiment can be applied to the third embodiment. Cut.

[0210] FIG. 8B shows a display. The display shown in FIG. 8B includes a housing 9310 and The display portion 9311 may include any of the display devices described in the above embodiments. and / or an image sensor may be applied.

[0211] FIG. 8(C) is a digital still camera. The digital still camera shown in FIG. , a housing 9320, a button 9321, a microphone 9322, a display unit 9323, The display portion 9323 may include the display device and / or image display device described in the above embodiment. A sensor can be applied.

[0212] By using one embodiment of the present invention, the reliability of an electronic device can be improved.

[0213] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiments. is. [Explanation of symbols]

[0214] 101 Substrate 102 Circuit Board 105 gate electrode layer 107 Gate insulating layer 109 Semiconductor layer 111a Source electrode layer 111b Drain electrode layer 114 First inorganic insulating film 113 Inorganic insulating film 115 Inorganic insulating film 117 Organic insulating film 119 Second inorganic insulating film 121 Transparent conductive layer 123 Transparent conductive layer 125 Liquid Crystal Layer 127 Transparent conductive layer 129 Second inorganic insulating film 150 transistors 170 Capacitive element 180 Capacitive element 1000 pixel unit 1001 Sealing material 1003 Signal line driver circuit 1004 Scanning line driving circuit 1018 FPC 4001 board 4002 Photodiode element 4016 Organic insulating film 4020 Inorganic insulating film 4024 Orientation film 4030 transistor 4032 Capacitor 4034 Liquid crystal element 4036 Gate Line 4040 transistor 4052 opposing substrate 4056 transistor 4057 Gate selection line 4058 Reset signal line 4059 Video signal line 4071 Output signal line 4084 Alignment film 4086 Organic insulating film 4088 Counter electrode 4096 liquid crystal layer 5042 Pixel section 8033 Fasteners 8034 Switch 8035 Power Switch 8036 Switch 8038 Operation switch 8630 chassis 8631 Display section 8631a Display section 8631b Display section 8633 Solar Cells 8634 Charge / discharge control circuit 8635 battery 8636 DC / DC converter 8637 Converter 9300 chassis 9301 Button 9302 Microphone 9303 Display section 9304 Speaker 9305 Camera 9310 chassis 9311 Display section 9320 chassis 9321 Button 9322 Microphone 9323 Display section

Claims

[Claim 1] A transistor, a first inorganic insulating film covering the transistor; an organic insulating film on the first inorganic insulating film; a first transparent conductive layer on the organic insulating film; a second inorganic insulating film on the first transparent conductive layer; a second transparent conductive layer provided on at least the first transparent conductive layer via the second inorganic insulating film, and electrically connected to a source electrode layer or a drain electrode layer of the transistor through an opening formed in the organic insulating film and the first inorganic insulating film; a pixel portion including a liquid crystal layer on the second transparent conductive layer, In the pixel portion, the second inorganic insulating film has an end portion in a region where the second inorganic insulating film overlaps the organic insulating film.

Images