Semiconductor device

Abstract

To suppress variation in electrical characteristics of a semiconductor device having an interlayer insulating film over a transistor using an oxide semiconductor as a semiconductor film.SOLUTION: The semiconductor device includes a first insulating film having a gap in a step region formed by a source electrode and a drain electrode on a semiconductor film and containing silicon oxide as a component, and a second insulating film provided in contact with the first insulating film so as to close the gap of the first insulating film and containing silicon nitride as a component. With such a structure, a void portion generated in the first insulating film can be prevented from extending further to the outside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention disclosed in this specification and the like relates to a semiconductor device and a method for manufacturing the semiconductor device.

[0002] In this specification and the like, a semiconductor device is a device that can function by utilizing semiconductor characteristics. Electro-optical devices, image display devices, semiconductor circuits, and electronic equipment are all semiconductor devices. It is a location. [Background technology]

[0003] A technology for constructing transistors using semiconductor thin films formed on substrates with insulating surfaces The transistor is used in integrated circuits (ICs) and image display devices (simply called display devices). These are widely used in electronic devices such as semiconductors that can be applied to transistors. Silicon-based semiconductor materials are widely known as conductive thin films, but other materials include oxides. Semiconductors are in the spotlight.

[0004] For example, zinc oxide or an In-Ga-Zn oxide semiconductor is used as the oxide semiconductor. A technique for fabricating a transistor using such a material has been disclosed (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-165528 Summary of the Invention [Problem to be solved by the invention]

[0006] Furthermore, for example, a semiconductor device (such as a liquid crystal panel) using a transistor including an oxide semiconductor can be When making a transistor using an oxide semiconductor, it is necessary to provide an interlayer insulating film on the transistor. .

[0007] In integrated circuits, the interlayer insulating film not only provides insulation between transistors and wiring, but also between wiring. This is an important factor in stabilizing the characteristics of the transistor.

[0008] Therefore, the present invention provides a semiconductor device having an interlayer insulating film on a transistor using an oxide semiconductor. One object is to suppress fluctuations in the electrical characteristics of the device. [Means for solving the problem]

[0009] One embodiment of the present invention is a semiconductor device formed by a source electrode and a drain electrode on a semiconductor film. a first insulating film having a gap in a step region formed by the first insulating film and containing silicon oxide as a component; The insulating film is provided in contact with the first insulating film so as to fill the gaps in the insulating film. By adopting this configuration, voids occurring in the first insulating film are eliminated. This can prevent the gap from spreading further outward. The configuration can be as follows.

[0010] One aspect of the present invention is a semiconductor device that at least partially overlaps with a gate electrode via a gate insulating film. a source electrode and a drain electrode having an area contacting a part of the upper surface of the semiconductor film; , the source electrode, the drain electrode and the semiconductor film are covered, and the source electrode and the drain electrode are formed on the semiconductor film. The step region formed by the drain electrode and the silicon dioxide layer has a gap. a first insulating film including a first insulating film and a second insulating film provided in contact with the first insulating film so as to close a void portion of the first insulating film; and a second insulating film containing silicon nitride as a component.

[0011] Another aspect of the present invention is a semiconductor film having a region in contact with a part of the upper surface of the semiconductor film. A source electrode, a drain electrode, and a semiconductor film are covered with the source electrode, the drain electrode, and the semiconductor film. A gap is provided in the step region formed by the source electrode and the drain electrode on the conductive film. a first insulating film containing silicon oxide as a component and a second insulating film configured to fill gaps in the first insulating film; a second insulating film containing silicon nitride as a component and provided in contact with the first insulating film; and a gate electrode overlapping the semiconductor film with an insulating film interposed therebetween.

[0012] Another embodiment of the present invention is a semiconductor device having the above structure, The doped electrode is a multilayer structure including a first conductive film in contact with the semiconductor film and a second conductive film on the first conductive film. It has a layer structure, and the side end surface of the second conductive film is on the top surface of the first conductive film.

[0013] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the first insulating film has a film density of 1000 .mu.m or less. is 2.26g / cm 3 More than 2.50g / cm 3 It is preferable that the following is true:

[0014] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the first insulating film is an oxide film. Preferably, the first insulating film is a silicon nitride film, and the second insulating film is a silicon nitride film.

[0015] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the thickness of the first insulating film is , which is larger than the thickness of the second insulating film.

[0016] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the semiconductor film is an oxide semiconductor. A conductive film is preferred.

[0017] In another embodiment of the present invention, a gate electrode is at least partially overlapped with the gate insulating film. a source electrode and a semiconductor film having a region in contact with a portion of the upper surface of the semiconductor film; and a drain electrode are formed to cover the source electrode, the drain electrode and the semiconductor film. a gap in a step region formed by the source electrode and the drain electrode in the A first insulating film containing silicon dioxide as a component is formed, and a silicon dioxide film is formed so as to close the voids in the first insulating film. A second insulating film containing silicon nitride as a component is formed in contact with the first insulating film. This is a method for manufacturing a semiconductor device.

[0018] Another embodiment of the present invention is a method for forming a semiconductor film, the method comprising: forming a semiconductor film; forming a source electrode and a drain electrode having a region, Covering the semiconductor film, formed by source and drain electrodes on the semiconductor film A first insulating film having a gap in the step region and containing silicon oxide as a component is formed, The insulating film is made of silicon nitride and is placed in contact with the first insulating film to fill the gaps in the insulating film. forming a second insulating film containing the semiconductor film, and forming a gate electrode on the second insulating film so as to overlap the semiconductor film; This is a method for manufacturing a semiconductor device.

[0019] Another embodiment of the present invention is a method for manufacturing a semiconductor device having the above structure, The drain electrode is made of a first conductive film in contact with the semiconductor film and a second conductive film on the first conductive film. The first conductive film and the second conductive film are etched to form an etched structure. By the etching process, the side end surfaces of the second conductive film are on the upper surface of the first conductive film.

[0020] Another embodiment of the present invention is a method for manufacturing a semiconductor device having the above structure, further comprising: The film density is 2.26 g / cm 3 More than 2.50g / cm 3 It is preferable that the following is true:

[0021] Another embodiment of the present invention is a method for manufacturing a semiconductor device having the above structure, further comprising: Preferably, the first insulating film is a silicon oxynitride film, and the second insulating film is a silicon nitride film.

[0022] Another embodiment of the present invention is a method for manufacturing a semiconductor device having the above structure, further comprising: The thickness of the film is greater than the thickness of the second insulating film.

[0023] Another embodiment of the present invention is a method for manufacturing a semiconductor device having the above structure, Preferably, the insulating film is an oxide semiconductor film. [Effects of the Invention]

[0024] According to one embodiment of the present invention, a highly reliable semiconductor device in which fluctuations in electrical characteristics are suppressed is provided. It is possible. [Brief explanation of the drawings]

[0025] [Figure 1] 1A and 1B are a plan view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 2] 1A to 1C illustrate an example of a method for manufacturing a semiconductor device. [Figure 3] 1A to 1C illustrate an example of a method for manufacturing a semiconductor device. [Figure 4] 1A and 1B are a plan view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 5] 1A to 1C illustrate an example of a method for manufacturing a semiconductor device. [Figure 6] 1A to 1C illustrate an example of a method for manufacturing a semiconductor device. [Figure 7] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 8]5A to 5C are cross-sectional views showing the process of void generation. [Figure 9] 1A and 1B are cross-sectional views illustrating one embodiment of a display device. [Figure 10] 1A and 1B are cross-sectional views illustrating one embodiment of a display device. [Figure 11] 1A and 1B are cross-sectional views illustrating one embodiment of a display device. [Figure 12] 1A to 1C illustrate one embodiment of a display device. [Figure 13] 1A to 1C illustrate one embodiment of a semiconductor device. [Figure 14] 1A to 1C illustrate electronic devices. [Figure 15] 1A to 1C illustrate electronic devices. [Figure 16] FIG. 2 shows a STEM image of an example sample in an example. [Figure 17] FIG. 2 shows a STEM image of an example sample in an example. [Figure 18] FIG. 2 shows a STEM image of an example sample in an example. [Figure 19] FIG. 10 is a diagram showing electrical characteristics of example samples in an example. [Figure 20] FIG. 10 is a diagram showing electrical characteristics of example samples in an example. [Figure 21] FIG. 2 is a diagram illustrating an example sample in an example. [Figure 22] FIG. 10 shows SIMS data of an example sample in an example. [Figure 23] FIG. 2 is a diagram illustrating an example sample in an example. [Figure 24] FIG. 10 shows SIMS data of an example sample in an example. [Figure 25] 10A and 10B are model diagrams illustrating transfer of nitrogen, hydrogen, and water in a nitrogen-containing oxide insulating film during heat treatment. [Figure 26] 10A and 10B are model diagrams illustrating transfer of nitrogen, hydrogen, and water in an oxide semiconductor film during heat treatment. [Figure 27] 10A and 10B are model diagrams illustrating changes in oxygen vacancies in an oxide semiconductor film due to heat treatment; DETAILED DESCRIPTION OF THE INVENTION

[0026] The following describes the embodiments in detail with reference to the drawings. The present invention is not limited to the embodiments described herein, and the forms and details thereof may be changed without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications may be made to the details. However, the present invention should not be construed as being limited to the description of the following embodiments.

[0027] The functions of "source" and "drain" may differ depending on the type of transistor used. Or, when the direction of the current changes during circuit operation, the positions may be reversed. Therefore, in this specification, the terms "source" and "drain" are used interchangeably. It is possible to do so.

[0028] "Electrically connected" means that the device is connected via "something that has some kind of electrical effect." Here, "something that has some kind of electrical effect" means an electrical There are no particular restrictions as long as it is possible to send and receive signals.

[0029] The position, size, range, etc. of each component shown in the drawings are not necessarily the same as those in the actual embodiment, in order to facilitate understanding. Therefore, the disclosed invention may not necessarily represent the actual position, size, range, etc. The position, size, range, etc. are not necessarily limited to those disclosed in the drawings, etc.

[0030] Ordinal numbers such as "first," "second," and "third" are used to avoid confusion of the components. That is why.

[0031] 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 of -5° or more and 5° or less. refers to the state in which two straight lines are arranged at an angle of 80° or more and 100° or less. , including cases where the angle is between 85° and 95°.

[0032] In this specification, when the crystal is a trigonal or rhombohedral crystal, it is represented as a hexagonal crystal system. vinegar.

[0033] (Embodiment 1) In this embodiment, a semiconductor device of one embodiment of the present invention will be described with reference to drawings. 1A and 1B are a top view and a cross-sectional view of a transistor 450, which is a semiconductor device of one embodiment of the present invention. 1A shows a top view of the transistor 450, and FIG. 1B shows a cross-sectional view of the transistor 450 at a point shown in FIG. 1A. 1 shows a cross-sectional view taken along the chain line AB.

[0034] The transistor 450 shown in FIG. 1 has a gate electrode provided on a substrate 400 having an insulating surface. An electrode 402, a gate insulating film 404 provided on the gate electrode 402, and a gate insulating film 4 A semiconductor film 406 is provided on the gate electrode 404 and overlaps with the gate electrode 402. The source electrode 408a and the drain electrode 408b are provided. An insulating film 412 that covers the electrode 408a and the drain electrode 408b and is in contact with the semiconductor film 406 The insulating film 412 may be formed as a component of the transistor 450. 14, and an opening formed in the insulating film 412 and the interlayer insulating film 414 on the interlayer insulating film 414. An electrode 416 is provided which is electrically connected to the drain electrode 408b via a portion. In this embodiment, the electrode 416 is electrically connected to the drain electrode 408b. However, the electrode 416 may be electrically connected to the source electrode 408a.

[0035] In this embodiment, the gate insulating film 404 is a gate insulating film in contact with the gate electrode 402. The gate insulating film 404a and the semiconductor film 406 are in contact with each other. The insulating film 412 is a stacked structure of the semiconductor film 406, the source electrode 408a, and the and the oxide insulating film 410, which is the first insulating film in contact with the drain electrode 408b. a laminated structure of a nitride insulating film 411 which is a second insulating film that functions as a protective film on the film 410; The oxide insulating film 410 covers the semiconductor film 406, the source electrode 408a, and the drain electrode 408b. an oxide insulating film 410a which is in contact with the gate electrode 408b, is formed under low power conditions, and has high coverage; The oxide insulating film 410b has a stacked structure over the oxide insulating film 410a.

[0036] In addition, the step on the side end surface of the source electrode 408a and the drain electrode 408b A void 413 is generated in the oxide insulating film 410 of the covering portion. Since the dielectric constant is lower than that of the film forming the portion 413, the dielectric constant between the wirings caused by miniaturization of semiconductor devices is reduced. This reduces the capacitance required, enabling high speed operation while maintaining a high degree of integration. Moisture penetrates into the semiconductor film 406 through the gap 413, and the characteristics of the transistor 450 deteriorate. However, by providing the nitride insulating film 411 over the oxide insulating film 410, The voids generated in the oxide insulating film 410 can be covered.

[0037] Furthermore, by blocking the gap 413 with the nitride insulating film 411, the oxide insulating film 41 0. In addition, the nitride insulating film 411 can prevent the void 413 from expanding outside the Therefore, the voids 413 may be filled. Hydrogen or a compound containing hydrogen (such as water) is absorbed into the semiconductor film 4 It acts as a barrier film to prevent penetration into 06.

[0038] Next, a method for manufacturing the transistor 450 will be described with reference to FIGS.

[0039] First, a gate electrode 402 (formed in the same layer as this) is formed on a substrate 400 having an insulating surface. (including wiring)

[0040] There are no major restrictions on the substrate that can be used for the substrate 400 having an insulating surface, but at least It is necessary to have at least a heat resistance sufficient to withstand the subsequent heat treatment. Glass substrates such as borosilicate glass and aluminoborosilicate glass, ceramic substrates, quartz A substrate, a sapphire substrate, etc. can be used. Also, a single substrate such as silicon or silicon carbide can be used. Crystalline semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, SO A substrate such as a semiconductor substrate can be used, and a substrate having a semiconductor element mounted thereon is called a substrate 40. It may be used as 0.

[0041] The material of the gate electrode 402 is molybdenum, titanium, tantalum, tungsten, aluminum, or the like. Metallic materials such as aluminum, copper, chromium, neodymium, scandium, etc., or alloys containing these as their main components The gate electrode 402 can be formed using a gold material. Semiconductor films, such as polycrystalline silicon films doped with silicon, and silicon films such as nickel silicide A silicide film may also be used.

[0042] The material of the gate electrode 402 includes indium oxide, tin oxide, and tungsten oxide. Indium oxide, indium zinc oxide with tungsten oxide, indium zinc oxide with titanium oxide Indium oxide, indium tin oxide with titanium oxide, indium oxide zinc oxide, acid Conductive materials such as indium tin oxide doped with silicon dioxide can also be applied.

[0043] Alternatively, the gate electrode 402 may be made of a nitrogen-containing In-Ga-Zn oxide, a nitrogen-containing In-Ga-Zn oxide, or a nitrogen-containing In-Ga-Zn oxide. In-Sn oxides containing nitrogen, In-Ga oxides containing nitrogen, In-Zn oxides containing nitrogen oxides, Sn-based oxides containing nitrogen, In-based oxides containing nitrogen, metal nitride films (indium nitride Alternatively, a film such as a titanium film, a zinc nitride film, a tantalum nitride film, or a tungsten nitride film may be used. Since the materials have a work function of 5 electron volts or more, it is possible to use these materials to fabricate gate electrodes. By forming 402, the threshold voltage of the transistor is made positive. This allows realizing a normally-off switching transistor. 402 may be a single layer structure, or a laminated structure in which, for example, copper is formed on tantalum nitride. The gate electrode 402 may have a tapered shape, for example, a taper angle of The taper angle is set to 15° or more and 70° or less. The angle between the side edge of the layer and the bottom surface of the layer.

[0044] Next, a gate insulating film 404 is formed on the gate electrode 402 so as to cover the gate electrode 402. The gate insulating film 404 is formed by a plasma CVD method, a sputtering method, or the like. Silicon oxide film, silicon oxynitride film, silicon nitride oxide film, silicon nitride film, etc. aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film aluminum film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, ceramic oxide film An insulating film containing at least one of a lithium oxide film and a neodymium oxide film is used as a single layer or a laminated layer. In addition, microwave plasma treatment is performed to repair oxygen vacancies after the gate insulating film 404 is formed. It is preferable to carry out the radical oxidation treatment by carrying out the following.

[0045] In this specification, the term "oxynitride" such as silicon oxynitride refers to a material having a specific composition. It refers to a material that contains more oxygen than nitrogen.

[0046] In this specification, the term "nitride oxide" such as silicon nitride oxide refers to the composition and It refers to a material that contains more nitrogen than oxygen.

[0047] In the gate insulating film 404, the region in contact with the semiconductor film 406 to be formed later (this In this embodiment, the gate insulating film 404b is preferably an oxide insulating film. .

[0048] Next, a semiconductor film 406 is formed on the gate insulating film 404 (see FIG. 2B).

[0049] The semiconductor film 406 may be an amorphous semiconductor film, a polycrystalline semiconductor film, or a microcrystalline semiconductor film. The amorphous semiconductor film may be made of silicon or silicon germanium (S An i-Ge alloy or the like can be used. Alternatively, an oxide semiconductor film can be used.

[0050] Next, a conductive film is formed on the semiconductor film 406, and this is processed by etching to form a semiconductor film. Source electrode 408a and drain electrode 408b (including wiring formed in the same layer) (See Figure 2(C)).

[0051] The source electrode 408a and the drain electrode 408b are made of, for example, Al, Cr, or Cu. a conductive film containing an element selected from the group consisting of Ta, Ti, Mo, and W, or a conductive film containing the above-mentioned elements as components; Metal nitride films (titanium nitride film, molybdenum nitride film, tungsten nitride film) can be used. In addition, Ti can be applied to either the upper or lower side of the conductive film such as Al or Cu, or both. , Mo, W, or their metal nitride films (titanium nitride film, molybdenum nitride film) Alternatively, the source electrode 408 may be a laminate of a tungsten film, a tungsten nitride film, or the like. The a and drain electrodes 408b may be formed of a conductive metal oxide. The oxides include indium oxide (In2O3), tin oxide (SnO2), and zinc oxide (Zn O), indium oxide tin oxide (In2O3-SnO2), indium oxide zinc oxide (I ZnO) or these metal oxide materials containing silicon oxide. It is possible.

[0052] The source electrode 408a and the drain electrode 408b are made of In-Ga- Zn-O film, In-Sn-O film containing nitrogen, In-Ga-O film containing nitrogen, I Metal nitride films such as n-Zn-O film, nitrogen-containing Sn-O film, and nitrogen-containing In-O film are used. The ends of the source electrode 408a and the drain electrode 408b can be tapered. It is preferable that the insulating film has a shape like a hole. Here, the taper angle is, for example, 30° or more and 70° or less, Preferably, the angle is between 30° and 60°.

[0053] In addition, the source electrode 408a and the drain electrode 408b are formed by using a material having a boundary layer such as a film having good adhesion and conductivity. In view of the surface characteristics, for example, as shown in FIG. 8(A), the conductive film 407a, the conductive film 407b, and When the conductive film 407c is formed as a stacked structure, the stacked conductive films are etched. When processing by this method, the etching speed differs depending on the type of conductive film. As shown in Fig. 1B, the side end surface of the conductive film 407c is in contact with the upper surface of the conductive film 407b, and the conductive film 407 The side end surface of b is in contact with the upper surface of the conductive film 407a, whereby the source electrode 408a and the drain electrode A step occurs on the side end surface of the pole 408b.

[0054] This step creates a void in the oxide insulating film 410 to be formed later, as shown in FIG. 8(C). In this embodiment, the source electrode 408a and the drain electrode 408b Although the description has been given using a laminated structure of conductive films with significant steps on the side end faces, the present invention is not limited to this. Even with a single conductive film, gaps are generated in the oxide insulating film 410 to be formed later due to the corners of the side end faces. The voids in the oxide insulating film 410 will be described later.

[0055] Next, the gate insulating film 404, the semiconductor film 406, the source electrode 408a and the drain electrode The oxide insulating film 410, which is part of the insulating film 412, is formed to cover the insulating film 408b (FIG. 3). (See (A)).

[0056] The oxide insulating film 410 is a stacked film of an oxide insulating film 410a and an oxide insulating film 410b. The semiconductor film 406 can be formed by plasma CVD or sputtering. It is preferable to use a film that can supply oxygen to the semiconductor film 406. The oxide insulating film 410 may be a single layer of a silicon oxide film, a silicon oxynitride film, or the like. Alternatively, a gallium oxide film or a gallium oxide film can be used as the oxide insulating film 410. Alternatively, an aluminum oxide film, an aluminum oxynitride film, or the like can be used.

[0057] The oxide insulating film 410a is placed in a processing chamber of a plasma CVD apparatus that has been evacuated. The substrate is maintained at 300°C or higher and 400°C or lower, more preferably 320°C or higher and 370°C or lower. The raw material gas is introduced into the processing chamber to set the pressure in the processing chamber to 100 Pa or more and 250 Pa or less. The oxide insulating film 410 is formed by supplying high frequency power to an electrode provided in the processing chamber. As a, a silicon oxide film or a silicon oxynitride film can be formed.

[0058] Under the film formation conditions, by setting the substrate temperature to the above temperature, the bond between silicon and oxygen As a result, the oxide insulating film 410a becomes oxygen-permeable, dense, and Hard oxide insulating film, typically etched with 0.5 wt % hydrofluoric acid at 25°C. A silicon oxide film or an oxide film having a grading rate of 10 nm / min or less, preferably 8 nm / min or less. A silicon nitride film can be formed.

[0059] Here, the oxide insulating film 410a is formed by using silane at a flow rate of 30 sccm and SiO 2 at a flow rate of 400 The source gas was nitrous oxide at 0 sccm, the pressure in the processing chamber was 200 Pa, and the substrate temperature was 22 At 0°C, a 27.12 MHz high-frequency power supply was used to apply 150 W of high-frequency power to parallel plate electrodes. A silicon oxynitride film with a thickness of 50 nm is formed by plasma CVD using the supplied gas. Under these conditions, a silicon oxynitride film that is permeable to oxygen can be formed.

[0060] The oxide insulating film 410b is placed in a processing chamber of a plasma CVD apparatus that has been evacuated. The substrate is maintained at 180°C or higher and 260°C or lower, more preferably 200°C or higher and 240°C or lower. A raw material gas is introduced into the processing chamber to set the pressure in the processing chamber at 100 Pa or more and 250 Pa or less. More preferably, the pressure should be between 100 Pa and 200 Pa, and the pressure should be 0. 17W / cm 2 More than 0.5W / cm 2 or less, more preferably 0.25 W / cm 2 Over 0 .35W / cm 2 Silicon oxide film or oxynitride film is formed by supplying the following high frequency power. A silicon dioxide film is formed.

[0061] The source gas of the oxide insulating film 410b is a deposition gas containing silicon and an oxidizing gas. Representative examples of deposition gases containing silicon include silane, disilane, and the like. Examples of oxidizing gases include silane, trisilane, and fluorinated silane. Examples of oxidizing gases include oxygen, ozone, and monoxide. Examples include dinitrogen and nitrogen dioxide.

[0062] The oxide insulating film 410b is formed under the following conditions: Supplying high-frequency power increases the efficiency of decomposing the source gas in the plasma, resulting in oxygen radicals. As a result, the oxygen content in the oxide insulating film 410b increases and the oxidation of the source gas progresses. However, when the substrate temperature is the above temperature, the silicon and the oxide Because the bonding strength of the atoms is weak, some of the oxygen is released by heating. The oxide insulating film contains more oxygen than the oxygen that fills the space, and some of the oxygen is released when heated. In addition, an oxide insulating film 410a is provided over the semiconductor film 406. Therefore, in the step of forming the oxide insulating film 410b, the oxide insulating film 410a is As a result, damage to the semiconductor film 406 is reduced while the The oxide insulating film 410b can be formed using high-frequency power with high power density.

[0063] In this manner, the oxide insulating film 410 is formed on the semiconductor film 406, the source electrode 408a, and the drain electrode 408b. an oxide insulating film 410a which is in contact with the gate electrode 408b, is formed under low power conditions, and has high coverage; A stacked-layer structure of the oxide insulating film 410b over the oxide insulating film 410a is preferable.

[0064] Furthermore, if there are steps on the side end surfaces of the source electrode 408a and the drain electrode 408b, When the oxide insulating film 410 is formed, a void 413 as shown in FIG. The void 413 is formed by observing the cross-sectional shape of the insulating film 412 using a scanning electron microscope (STEM). mission) electron microscopy method. It can be confirmed that the gap 413 has a lower dielectric constant than the film forming the gap 413. Therefore, it is possible to reduce the capacitance that occurs between wirings due to miniaturization of semiconductor devices, and To enable high-speed operation while maintaining a high degree of integration.

[0065] The oxide insulating film 410 is a low-density film that includes voids therein. 410 has voids (low density regions) and therefore has a lower film density as a whole. It has characteristics.

[0066] The insulating film 412 was measured by X-ray reflectometry (XRR). The preferred overall membrane density, as measured by y), is 2.26 g / cm 3 Over 2.50g / cm 3 The following is the result.

[0067] After the oxide insulating film 410 is formed, heat treatment may be performed. The temperature of the heat treatment is typically 150°C or higher and lower than the substrate strain point, preferably 200°C or higher and 450°C or lower, more preferably The temperature is 300℃ or higher and 450℃ or lower.

[0068] Next, a nitride insulating film 411 is formed to cover the oxide insulating film 410 (see FIG. 3(B)). (see).

[0069] The nitride insulating film 411 can be formed by plasma CVD or sputtering. Silicon nitride, silicon nitride oxide, or the like can be used in a single layer or in a laminated layer. The nitride insulating film 411 is made of aluminum nitride, aluminum nitride oxide, or the like. In addition, if the nitride insulating film 411 is a film with high coverage, the source electrode 408 The step on the side end surfaces of the a and drain electrodes 408b becomes gentler (the step portion becomes flat). This is preferable because it makes it difficult for gaps to form due to the step. Instead of the insulating film 411, aluminum oxide may be used.

[0070] The nitride insulating film 411 is formed on the steps of the side end surfaces of the source electrode 408a and the drain electrode 408b. The nitride insulating film 410 has a function of covering voids generated in the oxide insulating film 410 due to the difference. The gap is blocked by 411, so that the gap extends outside the oxide insulating film 410. In addition, the nitride insulating film 411 may fill the gaps. The nitride insulating film 411 is also resistant to hydrogen or oxygen from the outside or the interlayer insulating film 414 to be formed later. The barrier film prevents hydrogen-containing compounds (such as water) from penetrating into the semiconductor film 406. This functions as a gate electrode, thereby improving the reliability of the transistor.

[0071] Through the above steps, the transistor 450 of this embodiment can be formed.

[0072] Next, an interlayer insulating film 414 is formed over the transistor 450 .

[0073] The interlayer insulating film 414 is made of acrylic resin, epoxy resin, benzocyclobutene resin, or poly Organic materials such as imide and polyamide can be used. It is possible to use a polycarbonate resin, etc. It is also possible to stack multiple insulating films made of these materials. The interlayer insulating film 414 may be formed by layering.

[0074] Next, an opening is formed in the insulating film 412 and the interlayer insulating film 414, and the insulating film 412 is formed on the interlayer insulating film 414. An electrode 416 is formed which is electrically connected to the drain electrode 408b through the opening (FIG. 3( See C).

[0075] The electrode 416 is formed by appropriately using the material shown in the source electrode 408a or the drain electrode 408b. The electrode 416 can also be made of indium oxide containing tungsten oxide, Indium zinc oxide containing tungsten, indium oxide containing titanium oxide, titanium oxide Indium tin oxide containing tin, indium tin oxide (hereinafter referred to as ITO), Conductive materials with transparency such as indium zinc oxide and silicon oxide-doped indium tin oxide Materials can be used.

[0076] As a result, the voids in the oxide insulating film 410 have a lower dielectric constant than the film that forms the voids. Therefore, it is possible to reduce the capacitance that occurs between wirings due to miniaturization of semiconductor devices, and to achieve high integration. The nitride insulating film 411 blocks the gap. This can prevent voids from expanding outside the oxide insulating film 410. The gap may be filled with the nitride insulating film 411. Hydrogen or compounds containing hydrogen (such as water) may enter the insulating interlayer 414 from the outside or from the insulating interlayer 414 that will be formed later. Since it functions as a barrier film that prevents the penetration of the semiconductor film 406, It can improve the reliability of the 450.

[0077] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0078] (Embodiment 2) In this embodiment mode, a semiconductor device different from that in Embodiment Mode 1 will be described with reference to the drawings. 4A and 4B are a top view and a cross-sectional view of a transistor 550, which is a semiconductor device of one embodiment of the present invention. 4A shows a top view of transistor 550, and FIG. 4B shows the top view of transistor 550 shown in FIG. 1 is a cross-sectional view taken along dashed line CD. The transistor 50 has a top-gate structure, unlike the transistor 450 described in Embodiment 1. The difference is that it is a diaster.

[0079] The transistor 550 shown in FIG. 4 is a transistor including a base insulating layer provided on a substrate 400 having an insulating surface. The insulating film 401, the semiconductor film 406 provided on the insulating base film 401, and the insulating base film 401 and the semiconductor film 406 are and a source electrode 408a and a drain electrode 408b provided on the semiconductor film 406; A gate electrode 408a covers the source electrode 408a and the drain electrode 408b and is in contact with the semiconductor film 406. An insulating film 512 and a gate electrode provided on the gate insulating film 512 and overlapping with the semiconductor film 406 The electrode 402 also includes an interlayer insulating film 414 that covers the transistor 550, and an interlayer insulating film A drain electrode is formed on the film 414 through an opening provided in the insulating film 412 and the interlayer insulating film 414. An electrode 416 is provided which is electrically connected to the gate electrode 408b. The electrode 416 is electrically connected to the drain electrode 408b, but is not limited to this. 416 may be electrically connected to the source electrode 408a.

[0080] In this embodiment, the gate insulating film 512 is formed on the semiconductor film 406, the source electrode 408a, and the and an oxide insulating film 510 which is a first insulating film in contact with the drain electrode 408b. A laminated structure of a nitride insulating film 511, which is a second insulating film that functions as a protective film on the insulating film 510. The oxide insulating film 510 covers the semiconductor film 406, the source electrode 408a, and the drain electrode 408b. An oxide insulating film 510a that is in contact with the rain electrode 408b, is formed under low power conditions, and has high coverage. and an oxide insulating film 510b over the oxide insulating film 510a.

[0081] In addition, the step on the side end surface of the source electrode 408a and the drain electrode 408b A void 413 is generated in the oxide insulating film 510 of the covering portion. Since the dielectric constant is lower than that of the film forming the gap 413, the dielectric constant is reduced. This reduces the capacitance generated, enabling high speed operation while maintaining a high degree of integration. Moisture penetrates into the semiconductor film 406 through the gap 413, and the characteristics of the transistor 550 are deteriorated. Although there is a risk of adversely affecting the performance, it is preferable to provide the nitride insulating film 511 over the oxide insulating film 510. The voids generated in the oxide insulating film 510 can be covered with the insulating film 514.

[0082] Furthermore, by blocking the gap 413 with the nitride insulating film 511, the oxide insulating film 51 0. In addition, the nitride insulating film 511 can prevent the void 413 from expanding outside the Therefore, the voids 413 may be filled. Hydrogen or a compound containing hydrogen (such as water) is absorbed into the semiconductor film 4 It acts as a barrier film to prevent penetration into 06.

[0083] Next, a method for manufacturing the transistor 550 will be described with reference to FIGS.

[0084] First, a base insulating film 401 is formed on a substrate 400 having an insulating surface. The material and manufacturing method of the base insulating film 401 are the same as those of the substrate 400 and the gate insulating film of the first embodiment. The gate insulating film 404 can be taken into consideration.

[0085] Next, a semiconductor film 406 is formed on the base insulating film 401 (see FIG. 5A). The material and manufacturing method of the semiconductor film 406 can be referred to in Embodiment 1. Cut.

[0086] Next, a conductive film is formed on the semiconductor film 406, and this is processed by etching to form a semiconductor film. Source electrode 408a and drain electrode 408b (including wiring formed in the same layer) (See FIG. 5B) Materials for the source electrode 408a and the drain electrode 408b The source electrode 408a and the drain electrode 408b in Embodiment 1 are also fabricated by the same method as described above. can be taken into consideration.

[0087] As shown in the first embodiment, the source electrode 408a and the drain electrode 408b A step occurs on the side end surface, and this step causes a void in the gate insulating film 512 to be formed later. The void portion in the gate insulating film 512 will be described later.

[0088] Next, the base insulating film 401, the semiconductor film 406, the source electrode 408a and the drain electrode 408b are An oxide insulating film 510, which is a part of the gate insulating film 512, is formed so as to cover the oxide film 510. See Figure 5(C)).

[0089] The oxide insulating film 510 is formed on the base insulating film 401, the semiconductor film 406, and the source electrode 408. a and drain electrodes 408b, and is formed under low power conditions. It is preferable that the oxide insulating film 510a has a stacked structure of an oxide insulating film 510b over the oxide insulating film 510a. The material, the formation method, and the like of the oxide insulating film 510 are the same as those of the oxide insulating film 41 in Embodiment 1. 0 can be taken into consideration.

[0090] Furthermore, if there are steps on the side end surfaces of the source electrode 408a and the drain electrode 408b, When the oxide insulating film 510 is formed, the void 413 as described in Embodiment 1 is generated. The gap 413 has a lower dielectric constant than the film that forms the gap 413. This reduces the capacitance that occurs between wiring due to miniaturization, and allows for high integration while maintaining high density. Enables fast operation.

[0091] The oxide insulating film 510b is a low-density film that includes voids 413 therein. The insulating film 510b has a low density region, which results in a low film density as a whole. It has.

[0092] The gate insulating film 512 was measured by X-ray reflectometry (XRR). The preferred overall membrane density, as measured by the FTIR (FTIR) method, is 2.26 g / cm 3 2. 50g / cm 3 The following is the result.

[0093] Next, a nitride insulating film 511 is formed to cover the oxide insulating film 510 (see FIG. 6(A)). The material and manufacturing method of the nitride insulating film 511 are the same as those of the nitride insulating film 4 in the first embodiment. 11 can be taken into consideration.

[0094] The nitride insulating film 511 is formed on the steps of the side end surfaces of the source electrode 408a and the drain electrode 408b. The nitride insulating film 510 has a function of covering voids generated in the oxide insulating film 510 due to the difference. The gap is blocked by 511, so that the gap extends outside the oxide insulating film 510. In addition, the gaps may be filled with the nitride insulating film 511. The nitride insulating film 511 is also resistant to hydrogen or oxygen from the outside or the interlayer insulating film 414 to be formed later. The barrier film prevents hydrogen-containing compounds (such as water) from penetrating into the semiconductor film 406. This functions as a gate electrode, thereby improving the reliability of the transistor.

[0095] Next, the gate electrode 402 is formed on the gate insulating film 512 overlapping with the semiconductor film 406. (See FIG. 6B.) The material and manufacturing method of the gate electrode 402 are the same as those of the gate electrode in Embodiment 1. The port electrode 402 can be taken into consideration.

[0096] Through the above steps, the transistor 550 of this embodiment can be formed.

[0097] Next, the interlayer insulating film 414 is formed over the transistor 550, and the insulating film 412 and the interlayer insulating film 414 are An opening is provided in the insulating film 414, and the drain electrode 408 is formed on the insulating interlayer 414 through the opening. An electrode 416 is formed to electrically connect to the interlayer insulating film 414 and the insulating film 416b (see FIG. 6C). The materials and manufacturing methods of the interlayer insulating film 414 and the electrode 416 are the same as those of the interlayer insulating film 414 and the electrode 416 of the first embodiment. 416 can be taken into consideration.

[0098] 6(D), an oxide insulating film and a nitride insulating film are formed on the gate electrode 402. An insulating film 530 made of a nitride insulating film may be provided. As a result, a void is generated in the insulating film 530 due to the corners of the side end faces of the gate electrode 402. By forming the nitride insulating film, the voids are blocked by the nitride insulating film, and the voids are formed outside the oxide insulating film. In addition, the gate insulating film 512 is formed on the oxide insulating film. The insulating film 530 is not formed as a stack of nitride insulating films, but as a nitride insulating film covering an oxide insulating film. A laminated structure may also be used.

[0099] As a result, the gaps in the oxide insulating film 510 have a lower dielectric constant than the film that forms the gaps. Therefore, it is possible to reduce the capacitance that occurs between wirings due to miniaturization of semiconductor devices, and to achieve high integration. The nitride insulating film 511 shields the gap. By insulating the oxide insulating film 510, it is possible to prevent voids from expanding outside the oxide insulating film 510. The gap may be filled with the nitride insulating film 511. 11 is a compound containing hydrogen (such as water) from the outside or the interlayer insulating film 414 formed later. The film functions as a barrier film that prevents the penetration of the semiconductor film 406. The reliability of the resistor 550 can be improved.

[0100] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0101] (Embodiment 3) In this embodiment, a semiconductor device different from those in the first and second embodiments will be described with reference to FIG. This will be explained using:

[0102] The transistor 560 shown in FIG. 7A has a plurality of gate electrodes facing each other with a semiconductor film 406 interposed therebetween. The transistor 560 is characterized by having a substrate 400 having an insulating surface. a gate electrode 552 provided on the gate electrode 552; and a base insulating film 401 provided on the gate electrode 552. a semiconductor film 406 provided on the base insulating film 401; A source electrode 408a and a drain electrode 408b are provided on the film 406, and the source electrode The gate insulating film 51 covers the semiconductor film 406 and the drain electrode 408a. 2, a gate electrode 402 provided on the gate insulating film 512 and overlapping with the semiconductor film 406, In addition, an interlayer insulating film 414 covering the transistor 560 and a thin film on the interlayer insulating film 414 The drain electrode 40 is then electrically connected to the insulating film 412 via an opening provided in the insulating film 412 and the interlayer insulating film 414. An electrode 416 is provided which is electrically connected to 8b.

[0103] The material, manufacturing method, and the like of the gate electrode 552 are the same as those of the gate electrode 402 in Embodiment 1. You can pour drinks.

[0104] The transistor 560 described in this embodiment has a gate electrode facing the semiconductor film 406 therebetween. The gate electrode 552 and the gate electrode 402 are By applying different potentials, the threshold voltage of the transistor 560 can be controlled. Alternatively, the same potential may be applied to the gate electrode 552 and the gate electrode 402. The on-current of the transistor 560 can be increased.

[0105] The oxide insulating film 410 does not necessarily have to have a two-layer structure. The transistor 570 shown in FIG. 1 has the same structure as the transistor 450 in Embodiment 1 except for the oxide insulating film 41 0, an oxide insulating film 410c is further provided over the oxide insulating film 410b. In addition, the transistor 580 illustrated in FIG. 7C further includes an oxide insulating film 410c over the oxide insulating film 410c. The insulating film 410d and the oxide insulating film 410e are stacked. The oxide insulating film 410c and the oxide insulating film 410e are similar to the oxide insulating film 410a. The oxide insulating film 410d can be formed using a material similar to that of the oxide insulating film 410b. You can be there.

[0106] In addition, the oxide insulating film 410a formed at lower power than the oxide insulating film 410b has a lower The film is dense, and the step on the side end surfaces of the source electrode 408a and the drain electrode 408b is By laminating as above, the step can be made gentler. do.

[0107] Then, an oxide insulating film that is denser than the oxide insulating film 410a is formed over the oxide insulating film 410a. By forming the insulating film 410b, the oxide insulating film 410b becomes the oxide insulating film 410a. The effect (high coverage of steps, flattening the stepped areas) is effective in eliminating voids caused by steps. It becomes difficult to get into gaps.

[0108] The thickness of the semiconductor film 406 in a region in contact with the oxide insulating film 410a is The thickness of the semiconductor film 4 is smaller than that of the region in contact with the electrode 408a and the drain electrode 408b. In 06, the thin film region is the source electrode 408a and the drain electrode 408b. When processing the conductive film, a part of the conductive film is etched, or the source electrode 408 After forming the gate electrode 408a and the drain electrode 408b, the exposed region of the semiconductor film 406 is etched. The region is formed by performing a process on the transistor 570. This region functions as a channel forming region of the layer 580 .

[0109] In the semiconductor film 406, by reducing the film thickness of the channel forming region, the source electrode 4 The resistance of the region in contact with the drain electrode 408a and the drain electrode 408b is lower than that of the channel forming region. Therefore, the semiconductor film 406, the source electrode 408a, and the drain electrode This makes it possible to reduce the contact resistance with the electrode 408b.

[0110] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0111] (Fourth embodiment) In this embodiment, an oxide semiconductor film is used as the semiconductor film 406 in the above embodiment. This section explains what happens when:

[0112] A transistor including an oxide semiconductor film has a low current value in an off state (off-state current value). It can be easily controlled and has a relatively high field-effect mobility, making high-speed operation possible. In the above embodiment, the oxide insulating film under the nitride insulating film is formed by removing oxygen. By making it possible to supply a film, the voids that are closed by the nitride insulating film when heated can be eliminated. The above-mentioned effect is more pronounced by releasing oxygen from the gaps and supplying oxygen to the oxide semiconductor film. A method for forming an oxide semiconductor film will be described below.

[0113] The oxide semiconductor film is formed by sputtering, MBE (Molecular Beam Epitaxy), am Epitaxy) method, CVD (Chemical Vapor Depositi) method on) method, Pulsed Laser Deposition (P LD method), ALD (Atomic Layer Deposition) method, etc. are used appropriately. It is possible.

[0114] Furthermore, when a large amount of hydrogen is contained in the oxide semiconductor film, hydrogen is bonded to the oxide semiconductor. As a result, some of the hydrogen atoms become donors, generating electrons as carriers. The threshold voltage of the transistor is shifted in the negative direction. In this case, the hydrogen concentration is 5×10 18 atoms / cm 3 Less than 1 x 10 18 atoms / cm 3 Less than or equal to 5 × 10 17 atoms / cm 3 Further details are as follows: Preferably 1 x 10 16 atoms / cm 3 In the above-described oxide semiconductor film, The hydrogen concentration was measured by secondary ion mass spectrometry (SIMS). It is measured by IR Spectrometry.

[0115] For the above reasons, the gas used in forming the oxide semiconductor film is water, hydrogen, or water. It is preferable that impurities such as acid groups or hydrides are not included. In other words, the purity is 6N. or more, preferably 7N or more (i.e., the impurity concentration in the gas is 1 ppm or less, preferably 0 It is preferable to use a gas with a concentration of 0.1 ppm or less.

[0116] In addition, when forming an oxide semiconductor film, moisture (water, water vapor, hydrogen, hydroxyl) in the film formation chamber is To remove the ions (including radicals or hydroxides), an adsorption-type vacuum pump, e.g., a cryopump It is preferable to use a pump, an ion pump, or a titanium sublimation pump. The evacuation means may be a turbomolecular pump plus a cold trap. The film formation chamber is evacuated using a pump, and contains, for example, hydrogen atoms, water (H2O), and other gases containing hydrogen atoms. Since compounds (more preferably compounds containing carbon atoms) are exhausted, the film formation chamber The concentration of impurities such as hydrogen and moisture contained in the deposited oxide semiconductor film can be reduced.

[0117] The target used in the sputtering equipment should have a relative density of 90% or more and 100% or less. It is desirable that the relative density is 95% or more and 100% or less. By using the oxide semiconductor film, the oxide semiconductor film formed becomes dense.

[0118] As a material for the oxide semiconductor film, for example, an In-M-Zn-O based material may be used. Here, the metal element M is an element whose bond energy with oxygen is higher than that of In and Zn. Or, it is an element that has the function of suppressing the desorption of oxygen from In-M-Zn-O based materials. The metal element M acts to suppress the generation of oxygen vacancies in the oxide semiconductor film. This reduces the fluctuation in the electrical characteristics of the transistor caused by oxygen vacancies, improving reliability. Therefore, a transistor with high performance can be obtained.

[0119] The metal element M is specifically Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, G a, Y, Zr, Nb, Mo, Sn, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta or W may be used, and preferably A The metal element M is one of the above elements. Alternatively, two or more kinds may be selected. Also, Ge can be used in place of the metal element M.

[0120] Here, the oxide semiconductor represented by the In-M-Zn-O system material has the following characteristics: the higher the In concentration, the The carrier mobility and carrier density increase. As a result, the higher the In concentration, the higher the conductivity. It becomes an oxide semiconductor.

[0121] The structure of the oxide semiconductor film will be described below.

[0122] Oxide semiconductor films are roughly classified into single-crystal oxide semiconductor films and non-single-crystal oxide semiconductor films. The non-single-crystal oxide semiconductor film includes an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, a polycrystalline oxide semiconductor film, and a polycrystalline oxide semiconductor film. Compound semiconductor film, CAAC-OS (C Axis Aligned Crystallin e Oxide Semiconductor) film, etc.

[0123] An amorphous oxide semiconductor film has an irregular atomic arrangement in the film and does not contain crystalline components. The oxide semiconductor film does not have any crystalline parts even in the microscopic regions, and the entire film has a completely amorphous structure. A typical example is an oxide semiconductor film.

[0124] The microcrystalline oxide semiconductor film is made up of, for example, microcrystals (nanocrystals) with a size of 1 nm or more and less than 10 nm. Therefore, a microcrystalline oxide semiconductor film has a higher crystallinity than an amorphous oxide semiconductor film. The atomic arrangement is highly regular. Therefore, the microcrystalline oxide semiconductor film has a higher atomic regularity than the amorphous oxide semiconductor film. It has the advantage of having a lower defect level density than silicon.

[0125] The CAAC-OS film is one of the oxide semiconductor films with multiple crystal parts. The crystal part is small enough to fit inside a cube with a side length of less than 100 nm. The crystals contained in the OS film are cubes with sides of less than 10 nm, 5 nm, or 3 nm. The CAAC-OS film has a smaller size than the microcrystalline oxide semiconductor film. The CAAC-OS film has the advantage of having a low density of defect states. cormorant.

[0126] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a tron ​​microscope, clear boundaries between the crystalline parts are observed. It is not possible to confirm the grain boundary. It can be said that the AAC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0127] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). When observed, it can be confirmed that metal atoms are arranged in layers in the crystalline part. Each layer of the CAAC-OS film is formed on a surface (also called a surface to be formed) or on a concave surface of the upper surface. The shape reflects the convexity and is aligned parallel to the surface on which the CAAC-OS film is formed or the upper surface.

[0128] On the other hand, the CAAC-OS film was observed by TEM from a direction approximately perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystalline region. However, no regularity was observed in the arrangement of metal atoms between different crystal regions. do not have.

[0129] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It can be seen that this is the case.

[0130] X-ray diffraction (XRD) of the CAAC-OS film When structural analysis is performed using this device, for example, CAAC-OS with InGaZnO4 crystals can be seen. In the out-of-plane analysis of the film, the diffraction angle (2θ) peaks around 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis faces the surface on which the film is formed or the upper surface. It can be seen that the direction is roughly vertical.

[0131] On the other hand, the in-p X-rays incident on the CAAC-OS film are perpendicular to the c-axis. In the Lane analysis, a peak may appear around 2θ of 56°. The crystal structure of InGaZnO4 is composed of a single crystal of InGaZnO4. In the case of a nitride semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is the axis (φ axis). When the sample is rotated and analyzed (φ scan), a crystal plane equivalent to the (110) plane is detected. In contrast, in the case of the CAAC-OS film, six peaks are observed, which are assigned to 2θ. Even when the φ is fixed at around 56° and scanned, no clear peak appears.

[0132] From the above, it can be concluded that the orientation of the a-axis and b-axis is uniform between different crystal regions in the CAAC-OS film. Although it is irregular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface on which it is formed or the upper surface. Therefore, the layered structure confirmed by the cross-sectional TEM observation mentioned above is consistent with the Each layer of arranged metal atoms is a plane parallel to the ab plane of the crystal.

[0133] The crystalline part is formed when the CAAC-OS film is formed or after a crystallization treatment such as a heat treatment. As described above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is to be formed. Therefore, for example, in the CAAC-OS film, When the shape is changed by etching, the c-axis of the crystal is aligned with the CAAC-OS film. It may not be parallel to the normal vector of the face or top surface.

[0134] Furthermore, the crystallinity of the CAAC-OS film may not be uniform. When the crystalline part of the film is formed by crystal growth from the vicinity of the top surface of the CAAC-OS film, The area near the surface may have a higher crystallinity than the area near the surface to be formed. When impurities are added to the AC-OS film, the crystallinity of the region where the impurities are added changes, and the Regions of differing crystallinity may be formed.

[0135] In addition, the out-of-plane structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the NMR method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in part of the CAAC-OS film. The CAAC-OS film contains crystals that do not have crystalline structure. It is preferable that the peak is exhibited at 2θ of about 36° and that the peak is not exhibited at 2θ of about 36°.

[0136] The electrical characteristics of a transistor using a CAAC-OS film change when irradiated with visible or ultraviolet light. Therefore, the transistor has high reliability.

[0137] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, or a C The AAC-OS film may be a laminate film having two or more kinds of films.

[0138] The CAAC-OS film can be formed by sputtering a polycrystalline oxide semiconductor target. The film is formed by sputtering using the sputtering target. When the target collides with the ab plane, the crystalline region of the sputtering target cleaves from the ab plane, The particles peel off as flat or pellet-shaped sputtering particles with surfaces parallel to the b plane. In this case, the plate-like sputtered particles adhere to the substrate while maintaining their crystalline state. By reaching this temperature, a CAAC-OS film can be formed.

[0139] In addition, the following conditions are preferably applied to form the CAAC-OS film.

[0140] 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. The temperature is -80°C or lower, preferably -100°C or lower, and more preferably -120°C or lower. A membrane gas is used.

[0141] In addition, by increasing the substrate heating temperature during film formation, the microstructure of sputtered particles is improved after they reach the substrate. Specifically, the substrate heating temperature is set to 100°C or higher and 740°C or lower, preferably The film is formed at a temperature between 200°C and 500°C. When a flat sputtered particle reaches the substrate, migration occurs on the substrate. , the flat surface of the sputtered particle adheres to the substrate.

[0142] In addition, by increasing the oxygen ratio in the deposition gas and optimizing the power, plasma damage during deposition can be reduced. The oxygen ratio in the film forming gas is 30% by volume or more, preferably 100% by volume or more. Expressed as volume %.

[0143] As an example of a sputtering target, an In-Ga-Zn oxide target is The following are the results:

[0144] InO X powder, GaO Y Powder and ZnO Z The powders are mixed in a specified number of moles and pressurized. After that, it is heat-treated at a temperature between 1000℃ and 1500℃ to form polycrystalline In-G The target is a-Zn oxide, where X, Y, and Z are any positive numbers. , the predetermined molar ratio 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 depend on the sputtering target to be produced. The above can be changed as appropriate.

[0145] In addition, the oxide semiconductor film is in a supersaturated state immediately after deposition, where oxygen is more than the stoichiometric composition. For example, the oxide semiconductor film is preferably formed by sputtering. In this case, it is preferable to form the film under conditions where the proportion of oxygen in the film forming gas is high, and particularly in an oxygen atmosphere. It is preferable to form the film using oxygen gas (100% oxygen gas). When film formation is performed under poor conditions, especially in an atmosphere of 100% oxygen gas, for example, the film formation temperature is increased to 300°C or higher. Even if the film is made of a thin film, the release of Zn from the film is suppressed.

[0146] 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, an oxide containing three metal elements is used for the first oxide semiconductor film, and an oxide containing three metal elements is used for the second oxide semiconductor film. For example, an oxide containing two metal elements may be used as the first oxide semiconductor film and the second oxide semiconductor film. The oxide semiconductor films 2 may each be an oxide containing three metal elements.

[0147] In addition, the first oxide semiconductor film and the second oxide semiconductor film are made to contain the same constituent elements, and the combination of the two films is For example, the atomic ratio of the first oxide semiconductor film may be set to In:Ga:Zn= The atomic ratio of the second oxide semiconductor film is set to In:Ga:Zn=1:1:1, and the atomic ratio of the second oxide semiconductor film is set to In:Ga:Zn=3:1:2. The atomic ratio of the first oxide semiconductor film may be In:Ga:Zn=1:3:2. The atomic ratio of In:Ga:Zn in the second oxide semiconductor film may be 2:1:3.

[0148] At this time, the first oxide semiconductor film and the second oxide semiconductor film, which are closer to the gate electrode, The content ratio of In to Ga in the oxide semiconductor film is preferably In>Ga. The content ratio of In and Ga in the oxide semiconductor film on the far side may be set to In≦Ga.

[0149] In oxide semiconductors, the s orbitals of heavy metals mainly contribute to carrier conduction, and the inclusion of In Increasing the ratio tends to increase the overlap of s orbitals, so In>Ga The oxide with this composition has a higher mobility than the oxide with a composition of In≦Ga. In addition, the formation energy of oxygen vacancies in Ga is larger than that in In, so oxygen vacancies are less likely to occur. The oxides with a composition of In≦Ga have more stable characteristics than the oxides with a composition of In>Ga. To have sexuality.

[0150] An oxide semiconductor with a composition of In>Ga is applied to the channel side, and By applying an oxide semiconductor with a composition of In≦Ga to the other side of the panel, This makes it possible to further improve the mobility and reliability of the semiconductor.

[0151] In addition, the first oxide semiconductor film and the second oxide semiconductor film may be formed of oxide semiconductors having different crystallinity. That is, a single-crystal oxide semiconductor film, a polycrystalline oxide semiconductor film, an amorphous oxide semiconductor film, or the like may be used. A structure in which a nitride semiconductor film, a microcrystalline oxide semiconductor film, or a CAAC-OS film is appropriately combined. In addition, at least one of the first oxide semiconductor film and the second oxide semiconductor film may be When an amorphous oxide semiconductor is used for one of the two, the internal stress of the oxide semiconductor film and the external stress This reduces the variation in transistor characteristics and further improves the reliability of the transistor. It is possible to increase this to

[0152] On the other hand, amorphous oxide semiconductors are prone to absorbing impurities that act as donors, such as hydrogen. Oxygen vacancies are easily generated, making the oxide semiconductor film on the channel side n-type. It is preferable to use a crystalline oxide semiconductor film such as a CAAC-OS film.

[0153] In addition, the oxide semiconductor film has a stacked structure of three or more layers, and the amorphous semiconductor is formed by the crystalline semiconductor film of the multiple layers. A structure in which a conductor film is sandwiched may also be used. Alternatively, a crystalline semiconductor film and an amorphous semiconductor film may be stacked alternately. The structure may be such that:

[0154] In addition, in the case where the oxide semiconductor film has a stacked structure of a plurality of layers, the above structure can be realized by appropriately combining the layers. They can be used in combination.

[0155] In addition, the oxide semiconductor film has a stacked structure of multiple layers, and oxygen is added to each oxide semiconductor film after it is formed. The addition of oxygen can be performed by heat treatment in an oxygen atmosphere, ion implantation, ion doping, etc. ping method, plasma immersion ion implantation method, in an oxygen-containing atmosphere For example, a plasma treatment can be used.

[0156] By adding oxygen to each oxide semiconductor film, oxygen vacancies in the oxide semiconductor are reduced. This can increase the effectiveness of the system.

[0157] In addition, as an insulating film in contact with the oxide semiconductor film, X-ray reflectivity (XRR) was used. The preferred overall film density as measured by reflectometry is 2.26 g / cm 3 More than 2.50g / cm 3 The insulating film having a film density in this range has a high It is possible to combine the amount of oxygen released.

[0158] When forming an insulating film, activated species of the source gas are released onto the surface to be formed (here, the source electrode and the drain electrode). After being adsorbed on the insulating film (top surface of the insulating film), it migrates on the surface on which it is to be formed. When the film is capable of supplying the active species of the source gas, the dangling bonds of the active species of the source gas are absorbed by the insulating film. The activated species of the source gas are terminated with excess oxygen and stabilized, and the amount of migration of the activated species on the surface of the substrate is reduced. As a result, there are areas where it is difficult to form a film, such as steps, and voids are likely to occur. Furthermore, activated species of the source gas of the film to be formed thereafter are less likely to enter the gaps, The gap widens further.

[0159] Furthermore, by forming the nitride insulating film, the gap can be made into a closed space. The voids can absorb a large amount of oxygen, so oxygen from the oxide insulating film is absorbed during heating. Therefore, oxygen defects in the oxide semiconductor film can be eliminated by the oxide insulating film. This allows oxygen to be supplied from the source, improving the reliability of the transistor. do.

[0160] In addition, when oxide insulating films are stacked as shown in FIGS. 7B and 7C of the third embodiment, In this case, the oxide insulating film 410b serves as a film that supplies oxygen to the oxide semiconductor film. When the nitride insulating film 411 is formed in contact with the insulating film 410b by applying high power, the oxide insulating film 4 There is a risk that excess oxygen contained in 10b will be released, resulting in a decrease in oxygen supply capacity.

[0161] Therefore, the oxide insulating film 410c and the oxide insulating film 410d are formed directly under the nitride insulating film 411. By providing the insulating film 410e, the nitride insulating film 411 is formed, and thus the oxide insulating film 410b Therefore, a decrease in the oxygen supply ability of the oxide insulating film 410d can be suppressed.

[0162] Next, the oxide semiconductor film 31 and the oxide film capable of supplying oxygen are formed by heat treatment. The movement of nitrogen, hydrogen, and water in the insulating film 32 is modeled using FIGS. 25 to 27. 25 to 27, the dashed arrows indicate the movement of atoms due to heating. The solid arrows indicate the changes during or before and after the heat treatment. The insulating film 32 is an oxide insulating film containing more oxygen than the oxygen that satisfies the stoichiometric composition. This will be used to explain.

[0163] FIG. 25 shows a model of what may mainly occur in the oxide insulating film 32 due to heat treatment.

[0164] 25A shows the behavior of nitrogen atoms during heat treatment. The nitrogen atoms N (two nitrogen atoms in this case) are converted into the oxide insulating film 32 or the surface by the heat treatment. This model shows that the nitrogen atoms bond to each other at the oxygen atom, become nitrogen molecules, and are then desorbed from the oxide insulating film 32.

[0165] FIG. 25B is a model showing the behavior of oxygen atoms due to heat treatment. 2 contains more oxygen atoms than satisfy the stoichiometric composition (exO, here 2 The heat treatment causes the oxygen atoms to bond with each other in the oxide insulating film 32 or on the surface. The atoms become atoms and are released from the oxide insulating film 32 .

[0166] FIG. 25(C) is a model showing the behavior of hydrogen atoms and oxygen atoms due to heat treatment. The hydrogen atoms H (two hydrogen atoms in this example) and the stoichiometric The heat treatment causes more oxygen atoms exO than the oxygen that satisfies the composition to form the oxide insulating film 32 or The bond on the surface becomes water molecules, which are then desorbed from the oxide insulating film 32 .

[0167] FIG. 25(D) is a model showing the behavior of water molecules due to heat treatment. The water molecules contained in the oxide insulating film 32 are released from the oxide insulating film 32 by the heat treatment.

[0168] As shown in the above model, nitrogen, hydrogen, and fluorine are released from the oxide insulating film 32 by heat treatment. The nitrogen, hydrogen, and water contents in the film can be reduced by desorption of one or more of the nitrogen, hydrogen, and water. can.

[0169] Next, a model that may occur in the oxide semiconductor film 31 due to heat treatment will be explained with reference to FIG. Reveal.

[0170] 26A is a model showing the behavior of nitrogen atoms due to heat treatment in an oxide semiconductor film. The nitrogen atoms N (two nitrogen atoms in this case) contained in 31 are converted into oxide semiconductors by heat treatment. the oxide semiconductor film 31, the interface between the oxide semiconductor film 31 and the oxide insulating film 32, or the interface between the oxide insulating film 32 and the oxide semiconductor film 31 Alternatively, they bond on the surface to become nitrogen molecules, which are then desorbed from the oxide semiconductor film 31 .

[0171] FIG. 26(B) is a model showing the behavior of hydrogen atoms and oxygen atoms due to heat treatment. The hydrogen atoms H (here, two hydrogen atoms) contained in the oxide semiconductor film 31 are converted by the heat treatment. After moving to the oxide insulating film 32, the oxide insulating film 32 or its surface is stoichiometrically The oxygen atoms exO bond with more oxygen atoms than fill the composition, forming water molecules, and the oxide insulating film 3 Detach from 2.

[0172] FIG. 26(C) is a model showing different behavior of hydrogen atoms and oxygen atoms due to heat treatment. The amount of hydrogen atoms H contained in the oxide semiconductor film 31 is greater than the amount of oxygen that satisfies the stoichiometric composition. The oxide semiconductor film 31 or the oxide semiconductor film 3 1 and the oxide insulating film 32, and form water molecules. Detach.

[0173] Figures 26(D) and 26(E) show different behaviors of hydrogen atoms and oxygen atoms due to heat treatment. The hydrogen atoms H and oxygen atoms O contained in the oxide semiconductor film 31 are By the heat treatment, the oxide semiconductor film 31, the boundary between the oxide semiconductor film 31 and the oxide insulating film 32 The water molecules bond to the oxide insulating film 32 or its surface, and the water molecules are then bonded to the oxide insulating film 32 or its surface. At this time, the oxygen atoms are released from the insulating film 32. As shown in FIG. 26(E), the oxygen vacancy Vo occurs, but the compound contained in the oxide insulating film 32 More oxygen atoms exO than satisfy the stoichiometric composition move to the oxygen vacancy Vo, The oxygen vacancy Vo is filled and becomes an oxygen atom O.

[0174] From the above, it is considered that one or more of nitrogen, hydrogen, and water are removed from the oxide semiconductor film 31 by the heat treatment. By desorbing the carbon, the contents of nitrogen, hydrogen, and water in the film can be reduced.

[0175] Next, a model of change in oxygen vacancies in the oxide semiconductor film 31 due to heat treatment will be described with reference to FIG. 7 will be used to explain.

[0176] When more oxygen than the oxygen required for the stoichiometric composition moves to the oxide semiconductor film 31, More oxygen than meets the stoichiometric composition is transferred from the first oxygen atom to the first oxygen atom. The first oxygen atom that was expelled moves to the position of the second oxygen atom, and the second oxygen atom 2 oxygen atoms are pushed out. Thus, more oxygen than is required for the stoichiometric composition is present. When the oxygen atoms move to the oxide semiconductor film 31, the oxygen atoms are pushed out from among the oxygen atoms. In Figure 27, the pushing out of oxygen atoms between multiple oxygen atoms The three oxygen vacancies (Vo_1 to Vo_3) contained in the oxide semiconductor film 31 and the oxygen The oxygen contained in the oxide insulating film 32 that can supply oxygen, specifically, the oxygen of the stoichiometric composition The oxygen vacancy is changed by using more oxygen atoms (exO_1~exO_3) than the oxygen that satisfies the condition. The oxide insulating film 32 is formed under low power conditions and is coated with a stack of an oxide insulating film 32a that has high thermal conductivity and an oxide insulating film 32b that can supply oxygen; It is a membrane.

[0177] In FIG. 27, three oxygen vacancies (Vo_1 to Vo_ 3) and oxygen contained in the oxide insulating film 32b that can supply oxygen, specifically, It shows more oxygen atoms (exO_1~exO_3) than the stoichiometric composition.

[0178] Figure 27(A) shows the reaction between oxygen vacancies Vo_1 and oxygen atoms exO_1 due to heat treatment. The heat treatment results in the formation of more oxygen atoms exO_1 than the stoichiometric composition. The oxygen vacancies Vo_1 move to the positions of the oxygen vacancies Vo_1 included in the oxide semiconductor film 31. is filled in to form an oxygen atom O_1.

[0179] Next, as shown in FIG. 27(B), more oxygen atoms than the oxygen required for the stoichiometric composition are added. When exO_2 approaches the position of oxygen atom O_1 contained in the oxide semiconductor film 31, An oxygen atom O leaves the position of the atom O_1. The released oxygen atom O forms an oxygen vacancy Vo_2 The oxygen vacancy Vo_2 is filled and an oxygen atom O_2 is formed. The position of the desorbed oxygen atom O_1 becomes an oxygen vacancy, but an oxygen atom ex O_2 moves and becomes oxygen atom O_1a.

[0180] Next, as shown in FIG. 27(C), more oxygen atoms than the oxygen required for the stoichiometric composition are added. When exO_3 approaches the position of the oxygen atom O_1a contained in the oxide semiconductor film 31, An oxygen atom O is released from the position of atom O_1a. The released oxygen atom O is an oxygen atom O_ The oxygen atom O moves to position 2. The oxygen atom O leaves the oxygen atom O_2. The released oxygen atom O is The oxygen vacancy Vo_3 is filled and becomes an oxygen atom O_3. The position of the O_1a molecule becomes an oxygen vacancy, but the oxygen atom exO_3 moves to the oxygen vacancy, The oxygen atom O_1b is formed. The same is true for the oxygen atom O_2 from which the oxygen atom was removed. The oxygen vacancy is then filled by the oxygen atom O_1a, which moves to form the oxygen vacancy. It becomes the elementary atom O_2a.

[0181] Through the above steps, oxygen contained in the oxide insulating film 32b capable of supplying oxygen is It is possible to compensate for oxygen vacancies contained in the oxide semiconductor film 31. Not only the oxygen vacancies on the surface of the film 31 but also the oxygen vacancies in the film are filled by the heat treatment. From the above, the oxide insulating film 32b to which oxygen can be supplied while being heated is formed. Alternatively, after providing the oxide insulating film 32b capable of supplying oxygen, heat treatment is performed. By performing this treatment, the amount of oxygen vacancies in the oxide semiconductor film 31 can be reduced. .

[0182] In addition, oxygen is introduced into the back channel of the oxide semiconductor film 31 as the oxide insulating film 32a. Through the permeable oxide insulating film, oxide containing more oxygen than the oxygen that satisfies the stoichiometric composition is formed. By providing the oxide insulating film 32b, oxygen is moved to the back channel side of the oxide semiconductor film 31. This makes it possible to reduce oxygen deficiency in the region.

[0183] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0184] (Embodiment 5) A semiconductor device having a display function (display) using the transistors exemplified in the above embodiments (display In addition, a part of a driver circuit including a transistor can be manufactured. Alternatively, the entire display can be formed on the same substrate as the pixel section to form a system-on-panel. In this embodiment, a display device using the transistors shown as examples in the above embodiment will be described. An example of the device will be described with reference to FIGS. 9 to 12. In addition, FIGS. 10(A) and 10(B) 11 is a cross-sectional view showing the cross-sectional structure of the portion indicated by the dashed line MN in FIG. 9(B). is.

[0185] In FIG. 9A, a pixel portion 902 provided on a first substrate 901 is surrounded by a A sealing material 905 is provided, and the substrate is sealed with a second substrate 906. In this case, a region different from the region surrounded by the sealing material 905 on the first substrate 901 is In the signal line driving region, a signal line formed of a single crystal semiconductor or a polycrystalline semiconductor on a separately prepared substrate is A signal line driver circuit 903 and a scanning line driver circuit 904 are mounted on the display panel. 3. Various signals and potentials given to the scanning line driver circuit 904 or the pixel portion 902 are PC(Flexible printed circuit)918a, FPC918b is supplied by

[0186] In FIG. 9B and FIG. 9C, a pixel portion 902 provided on a first substrate 901 A sealant 905 is provided so as to surround the scanning line driver circuit 904. A second substrate 906 is provided on the pixel portion 902 and the scanning line driver circuit 904. The pixel portion 902 and the scanning line driver circuit 904 are formed by a first substrate 901, a sealing material 905, and a second substrate 906. The display element is sealed by the second substrate 906. ) is different from the region surrounded by the sealing material 905 on the first substrate 901. A signal line formed of a single crystal semiconductor or a polycrystalline semiconductor on a separately prepared substrate is placed in the region where the signal line is to be formed. A driving circuit 903 is mounted. In FIG. 9B and FIG. 9C, the signal line driving Various signals and voltages are applied to the circuit 903, the scanning line driver circuit 904, or the pixel portion 902. The position is supplied by FPC918.

[0187] In addition, in FIG. 9(B) and FIG. 9(C), a signal line driver circuit 903 is separately formed, Although an example in which the scanning line driver is mounted on the first substrate 901 is shown, the present invention is not limited to this configuration. Alternatively, a driving circuit may be formed separately and mounted, or a part of a signal line driving circuit or a scanning line driving circuit may be mounted. Only a part of it may be formed separately and mounted.

[0188] The method of connecting the separately formed drive circuit is not particularly limited, and may be a COG (C Hip On Glass method, wire bonding method, or TAB (Tape On Glass) method The Automated Bonding method can be used. This is an example in which a signal line driver circuit 903 and a scanning line driver circuit 904 are implemented by the COG method. 9(B) is an example in which a signal line driver circuit 903 is mounted by the COG method, and FIG. 9(C) is This is an example in which a signal line driver circuit 903 is mounted by the TAB method.

[0189] The display device includes a panel in which a display element is sealed, and a controller for the panel. This includes modules in which ICs, etc., including lasers, are mounted.

[0190] In this specification, the term "display device" refers to an image display device, a display device, or Refers to light sources (including lighting devices), and connectors such as FPC or TAB tape. Or a module with a TCP attached, a printed wiring board attached to the TCP A module in which an IC (integrated circuit) is directly mounted on a module or display element using the COG method. All modules are included in the display device.

[0191] The pixel portion and the scanning line driver circuit provided on the first substrate include a plurality of transistors. The transistor described in the above embodiment can be applied to the semiconductor device.

[0192] Examples of display elements provided in the display device include liquid crystal elements (also called liquid crystal display elements), light-emitting elements, and the like. The light-emitting element can be a light-emitting display element. This category includes elements whose brightness is controlled by the light emitted from the light source, specifically inorganic EL (Electroluminescent) luminescence elements, organic EL elements, etc. Also, electronic ink A display medium whose contrast changes due to an electrical effect can also be applied.

[0193] The display device shown in FIG. 10(A) has a connection terminal electrode 915 and a terminal electrode 916. The connection terminal electrode 915 and the terminal electrode 916 are anisotropically conductive with the terminals of the FPC 918. The electrodes are electrically connected via the electrode 919 .

[0194] The connection terminal electrode 915 is formed from the same conductive film as the first electrode 930, and the terminal electrode 916 are the source and drain electrodes of the transistor 910 and the transistor 911 (hereinafter, The pair of electrodes is formed of the same conductive film as the pair of electrodes.

[0195] The display device shown in FIG. 10(B) includes a connection terminal electrode 915a, a connection terminal electrode 915b, and The terminal electrode 916 is connected to the connection terminal electrode 915a, the connection terminal electrode 915b, and the terminal The electrode 916 is electrically connected to a terminal of the FPC 918 via an anisotropic conductive material 919. It is being done.

[0196] The connection terminal electrode 915a is formed from the same conductive film as the first electrode 930. The terminal electrode 915b is formed from the same conductive film as the third electrode 941. The electrode of the first electrode 910 is formed of the same conductive film as that of the pair of electrodes of the transistor 911 .

[0197] As shown in FIG. 11, the semiconductor device has a connection terminal electrode 955 and a terminal electrode 916. The connection terminal electrode 955 and the terminal electrode 916 are different from the terminals of the FPC 918. They are electrically connected via a dipole conductive agent 919 .

[0198] The connection terminal electrode 955 is formed from the same conductive film as the second electrode 931, and the terminal electrode 916 The pair of electrodes of the transistor 910 and the transistor 911 are formed using the same conductive film. do.

[0199] In addition, a pixel portion 902 and a scanning line driver circuit 904 provided on a first substrate 901 are 10 and 11, the transistors included in the pixel section 902 are 9 illustrates a transistor 910 included in the scan line driver circuit 904 and a transistor 911 included in the scan line driver circuit 904. In FIG. 10(A) and FIG. 10(B), transistors 910 and 911 An insulating film 924 corresponding to the insulating film 412 described in Embodiment 1 is provided on the insulating film 924. An interlayer insulating film 921 that functions as a planarizing film is further provided on the insulating film. 923 is an insulating film that functions as a base film.

[0200] In this embodiment, the transistors 910 and 911 are the same as those in the above embodiment. The transistor shown in can be applied.

[0201] 11, the semiconductor of the transistor 911 for the driver circuit is formed over the insulating film 924. 9 shows an example in which a conductive film 917 is provided at a position overlapping with a channel forming region of the body membrane. Note that an oxide semiconductor film is used as the semiconductor film. By placing it in a position that overlaps with the channel formation area, the The fluctuation amount of the threshold voltage of the resistor 911 can be further reduced. The potential of the transistor 7 may be the same as or different from the gate electrode of the transistor 911. The conductive film 917 can also function as a second gate electrode. , GND, 0V, or may be floating.

[0202] The conductive film 917 also has a function of blocking an external electric field. (circuit parts including transistors) The shielding function of the conductive film 917 prevents the influence of external electric fields such as static electricity. This can prevent the electrical characteristics of the transistor from being changed. The present invention can be applied to any of the transistors described in the above embodiment modes.

[0203] The transistor 910 provided in the pixel portion 902 is electrically connected to a display element. The display element is not particularly limited as long as it can display, and various display elements can be used. It can be used.

[0204] The first electrode and the second electrode (pixel electrode, common electrode, counter electrode) that apply a voltage to the display element In the case of a light source, the direction of the light to be extracted, the location of the electrode, and the The transparency or reflectivity can be selected depending on the pattern structure.

[0205] The first electrode 930, the second electrode 931, and the third electrode 941 include tungsten oxide. Indium oxide, indium zinc oxide with tungsten oxide, indium zinc oxide with titanium oxide Indium oxide, indium tin oxide containing titanium oxide, indium tin oxide (hereinafter referred to as I TO), indium zinc oxide, indium tin oxide with silicon oxide added, etc. A light-transmitting conductive material such as the above can be used.

[0206] The first electrode 930, the second electrode 931, and the third electrode 941 are made of tungsten (W ), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V ), niobium (Nb), tantalum (Ta), chromium (Cr), cobalt (Co), nickel (Ni), titanium (Ti), platinum (Pt), aluminum (Al), copper (Cu), silver (A g) or their alloys, or their metal nitrides. It can be formed by

[0207] The first electrode 930, the second electrode 931, and the third electrode 941 are made of a conductive polymer. The conductive layer can be formed using a conductive composition containing a conductive polymer. As the polymer, a so-called π-electron conjugated conductive polymer can be used. rianiline or its derivatives, polypyrrole or its derivatives, polythiophene or its derivatives derivatives thereof, or copolymers or copolymers of two or more of aniline, pyrrole and thiophene and derivatives thereof.

[0208] FIG. 10 shows an example of a liquid crystal display device using a liquid crystal element as a display element. This is an example of adopting the vertical electric field method.

[0209] In FIG. 10A, a liquid crystal element 913 which is a display element has a first electrode 930, a second electrode 931, a The liquid crystal layer 908 is sandwiched between an alignment film and an electrode 931. The second electrode 931 is provided with an insulating film 932 and an insulating film 933 which function as a second electrode. The first electrode 930 and the second electrode 931 are disposed on the second substrate 906 side, and are connected to the liquid crystal layer 908. The structure is such that they overlap through the

[0210] In FIG. 10B, a liquid crystal element 943, which is a display element, is formed on an interlayer insulating film 921. The liquid crystal layer 908 includes a first electrode 930, a third electrode 941, and a liquid crystal layer 908. 41 functions as a common electrode. An insulating layer is provided between the first electrode 930 and the third electrode 941. The insulating film 944 is formed using a silicon nitride film. Insulating films 932 and 933 are provided to sandwich the crystal layer 908 and function as alignment films. It is being done.

[0211] The spacers 935 are columnar spacers obtained by selectively etching the insulating film. The distance between the first electrode 930 and the second electrode 931 (cell gap) is controlled by the It is to be noted that a spherical spacer may also be used.

[0212] When liquid crystal elements are used as display elements, thermotropic liquid crystals, low molecular weight liquid crystals, polymer Liquid crystal, polymer dispersed liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. can be used. These liquid crystal materials can be in a cholesteric phase, smectic phase, cubic phase, or chromatic phase depending on the conditions. It shows an isotropic phase, an isotropic phase, etc.

[0213] Alternatively, a liquid crystal that exhibits a blue phase without using an alignment film may be used. When the temperature of the cholesteric liquid crystal is increased, the cholesteric phase transitions to the isotropic phase. The blue phase appears only in a narrow temperature range, so it is necessary to improve the temperature range. In order to improve the liquid crystal layer, a liquid crystal composition containing a chiral agent is used. The liquid crystal composition containing the liquid crystal and the chiral agent has a short response time of 1 msec or less, and is optically Since it is tropotropic, no alignment treatment is required and the viewing angle dependency is small. Since the rubbing process is unnecessary, electrostatic breakdown caused by the rubbing process can be prevented. Therefore, defects and damage to the liquid crystal display device during the manufacturing process can be reduced. Therefore, it is possible to improve the productivity of the liquid crystal display device.

[0214] The first substrate 901 and the second substrate 906 are fixed together by a sealant 925 . The sealant 925 can be made of an organic resin such as a thermosetting resin or a photosetting resin.

[0215] In the liquid crystal display device shown in FIG. 10A, the sealing material 925 is a gate insulating film. The interlayer insulating film 921 is provided on the inside of the sealing material 925. The insulating film 922 is formed by stacking a silicon nitride film and a silicon oxynitride film. When the insulating film 924 is selectively etched, the oxide nitride silicon oxide film on the upper layer of the gate insulating film 922 is removed. Preferably, the silicon film is etched to expose the silicon nitride film. The silicon nitride film formed on the gate insulating film 922 is in contact with the insulating film 925. It is possible to prevent water from entering the inside of the seal material 925 from the outside.

[0216] In the liquid crystal display device shown in FIG. 10B, the sealant 925 is in contact with the insulating film 924. The interlayer insulating film 921 is provided on the inner side of the sealing material 925. Since the silicon nitride film on the surface of the insulating film 924 comes into contact with the sealing material 925, water from the outside is prevented from entering the sealing material 924. It is possible to suppress penetration into the interior of 25.

[0217] The size of the storage capacitor provided in the liquid crystal display device is determined by the It is set so that the charge can be maintained for a predetermined period, taking into consideration the break current, etc. By using a transistor with a nitride semiconductor film, the liquid crystal capacitance in each pixel It is sufficient to provide a storage capacitor having a capacity of 1 / 3 or less, preferably 1 / 5 or less. Therefore, the aperture ratio of the pixel can be increased.

[0218] In addition, in display devices, black matrices (light-shielding films), polarizing members, phase difference members, reflectors, Optical members (optical substrates) such as anti-reflection members are provided as appropriate. Circularly polarized light from a differential substrate may also be used. may also be used.

[0219] 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 The color is not limited to the three colors RGBW (W represents white, G represents red, G represents green, and B represents blue). ) or RGB plus one or more colors such as yellow, cyan, or magenta. The size of the display area may be different for each dot of the color element. The present invention is not limited to color display devices, but may also be applied to monochrome display devices. It is also possible to do so.

[0220] FIG. 12 shows a second electrode provided on the substrate 906 in the display device shown in FIG. An example in which a common connection part (pad part) for electrically connecting with 931 is formed on the substrate 901 Shows.

[0221] The common connection portion is disposed at a position overlapping the sealing material for bonding the substrate 901 and the substrate 906. and electrically connected to the second electrode 931 via conductive particles contained in the sealing material. Or, a common connection part is provided in a place where it does not overlap with the sealing material (excluding the pixel part), and the common A paste containing conductive particles is provided separately from the sealing material so as to overlap the connection portion, forming a second electrode 9 31 may be electrically connected.

[0222] FIG. 12(A) is a cross-sectional view of the common connection portion, and corresponds to IJ in the top view shown in FIG. 12(B). Correct.

[0223] The common potential line 975 is provided on the gate insulating film 922 and is connected to the transistor 9 shown in FIG. 10 is made of the same material and in the same process as the source electrode 971 or the drain electrode 973 of do.

[0224] The common potential line 975 is covered with the insulating film 924 and the interlayer insulating film 921. 24 and the interlayer insulating film 921 have a plurality of openings at positions overlapping with the common potential line 975. This opening is for the source electrode 971 or the drain electrode 973 of the transistor 910. The contact hole connecting one of the first electrodes 930 and the second electrode 931 is fabricated in the same process.

[0225] In addition, the common potential line 975 and the common electrode 977 are connected at the opening. 77 is provided on the interlayer insulating film 921 and is connected to the connection terminal electrode 915 and the first electrode 9 of the pixel portion. It is made from the same materials and in the same process as the 30.

[0226] In this way, the common connection portion is formed by the same manufacturing process as the switching element of the pixel portion 902. It can be manufactured.

[0227] The common electrode 977 is an electrode that comes into contact with the conductive particles contained in the sealing material, and is connected to the substrate 906 Electrical connection is made with the second electrode 931 of the first electrode 931 .

[0228] 12C, the common potential line 985 is connected to the gate of the transistor 910. The electrode may be made of the same material and in the same process as the electrode.

[0229] In the common connection portion shown in FIG. 12(C), the common potential line 985 is connected to the gate insulating film 922, The insulating film 924 and the interlayer insulating film 921 are provided below the gate insulating film 922 and the insulating film 924 and the interlayer insulating film 921 have a plurality of openings at positions overlapping with the common potential line 985. The opening is formed at the source electrode 971 or the drain electrode 973 of the transistor 910. The insulating film 924 and the contact hole connecting the first electrode 930 are formed in the same process. After etching the interlayer insulating film 921, the gate insulating film 922 is selectively etched. It is formed by

[0230] In addition, the common potential line 985 and the common electrode 987 are connected at the opening. 87 is provided on the interlayer insulating film 921, and is connected to the connection terminal electrode 915 and the first electrode 9 of the pixel portion. It is made from the same materials and in the same process as the 30.

[0231] In the FFS mode liquid crystal display device shown in FIG. 10(B), the common electrode 977, 987 are each connected to the third electrode 941 .

[0232] Next, as a display element included in the display device, a light-emitting device using electroluminescence is used. The light-emitting element using electroluminescence can be applied to a light-emitting material. They are classified according to whether the material is an organic compound or an inorganic compound. The latter is called an inorganic EL element.

[0233] In an organic EL element, when a voltage is applied to the light-emitting element, electrons and positive electrodes are released from a pair of electrodes. The holes are then injected into a layer containing a light-emitting organic compound, allowing a current to flow. The recombination of carriers (electrons and holes) causes light-emitting organic compounds to form excited states. The excited state is formed, and light is emitted when the excited state returns to the ground state. Such a light-emitting element is called a current-excited light-emitting element.

[0234] Inorganic EL elements are classified into dispersion-type inorganic EL elements and thin-film-type inorganic EL elements depending on the element structure. Dispersion-type inorganic EL elements have a light-emitting layer in which particles of light-emitting material are dispersed in a binder. The emission mechanism is a donor- The thin-film inorganic EL element is an acceptor recombination type luminescence element. The luminescent layer is sandwiched between dielectric layers. The structure is sandwiched between electrodes, and the light emission mechanism is the inner shell electron transition of the metal ion. This is a localized light emission that utilizes organic EL elements. do.

[0235] The light emitting element only needs to have at least one of the pair of electrodes transparent in order to extract light. Then, a transistor and a light emitting element are formed on the substrate, and light is emitted from the surface opposite to the substrate. Top emission, bottom emission, and light emission from the substrate side. There are light emitting elements with a double-sided emission structure that emits light from the side, and light emitting elements with any emission structure are suitable. It can be used.

[0236] FIG. 11 shows an example of a light-emitting device using a light-emitting element as a display element. The transistor 963 is electrically connected to the transistor 910 provided in the pixel portion 902. The light emitting element 963 is configured as an assembly of a first electrode 930, a light emitting layer 951, and a second electrode 931. The layer structure is not limited to the configuration shown in the figure. In accordance with this, the configuration of the light emitting element 963 can be changed as appropriate.

[0237] A silicon nitride film 950 is provided between the interlayer insulating film 921 and the first electrode 930. The silicon film 950 contacts the side surfaces of the interlayer insulating film 921 and the insulating film 924. Silicon nitride The membrane 950 and the first electrode 930 have a partition wall 960 on the edge thereof. The partition wall 960 is made of an organic insulating material. In particular, a photosensitive resin material is used to form the first electrode. An opening is formed on the pole 930, and the sidewall of the opening has a continuous curvature. It is preferable to form it so as to have a flat surface.

[0238] The light-emitting layer 951 may be composed of a single layer or a plurality of layers stacked together. Either way is fine.

[0239] The second electrode 9 A protective layer may be formed on the insulating film 31 and the partition wall 960. The protective layer may be formed of silicon nitride, nitride, or the like. Silicon oxide, aluminum oxide, aluminum nitride, aluminum oxynitride, oxynitride The first substrate 901 and the second substrate 902 can be formed with aluminum nitride, DLC film, etc. A filler 964 is provided in the space sealed by the substrate 906 and the sealant 936. This provides a highly airtight and low outgassing protection against exposure to the outside air. Packaging with film (lamination film, UV curing resin film, etc.) or cover material It is preferable to enclose the substance.

[0240] The sealant 936 is made of organic resin such as thermosetting resin or photocuring resin, or a freezer containing low-melting glass. Frit glass can be used. Frit glass has high resistance to impurities such as water and oxygen. In addition, when frit glass is used as the sealing material 936, In this case, as shown in FIG. 11, by providing frit glass on the silicon nitride film 950, the nitride The adhesiveness of the silicon dioxide film 950 and the frit glass is improved, and the sealing material 9 36It is possible to prevent water from entering the interior.

[0241] Filler 964 can be an inert gas such as nitrogen or argon, or an ultraviolet curing resin or Thermosetting resins can be used, such as PVC (polyvinyl chloride), acrylic resin, Imide, epoxy resin, silicone resin, PVB (polyvinyl butyral) or EVA (ethylene vinyl acetate) can be used. For example, nitrogen can be used as a filler. That's fine.

[0242] If necessary, a polarizing plate or a circular polarizing plate (including an elliptical polarizing plate) may be attached to the light-emitting surface of the light-emitting element. ), retardation plates (λ / 4 plate, λ / 2 plate), color filters, and other optical films are provided as needed. Alternatively, an anti-reflection film may be provided on the polarizing plate or the circular polarizing plate. This allows for anti-glare treatment to be applied, which can diffuse reflected light and reduce glare.

[0243] In addition, since transistors are easily damaged by static electricity, etc., a protective circuit for protecting the drive circuit is It is preferable to provide a path. The protection circuit is preferably constructed using a non-linear element.

[0244] As described above, by using the transistor described in the above embodiment, Therefore, a highly reliable semiconductor device can be provided.

[0245] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiment modes. It is Noh.

[0246] (Embodiment 6) The transistors of the above-described embodiments are used to provide an image sensor that reads information about an object. Therefore, a semiconductor device having a sensor function can be manufactured.

[0247] FIG. 13A shows an example of a semiconductor device having an image sensor function. 13(B) is a cross-sectional view showing a part of the photosensor. do.

[0248] The photodiode 602 has one electrode connected to a photodiode reset signal line 658, The other electrode is electrically connected to the gate of transistor 640. 0 indicates that either the source or the drain is connected to the photosensor reference signal line 672. The other of the drains is electrically connected to one of the source and drain of the transistor 656. The transistor 656 has a gate connected to a gate signal line 659 and a source or drain connected to a The other end is electrically connected to a photosensor output signal line 671 .

[0249] Note that in the circuit diagrams in this specification, a transistor including an oxide semiconductor film is not clearly shown. In order to make it clear, the symbol for a transistor using an oxide semiconductor film is denoted by “OS.” In FIG. 13A, transistors 640 and 656 are the same as those in the previous embodiment. The transistor shown in the embodiment can be applied to the present invention, which is a transistor including an oxide semiconductor film. In this embodiment, a transistor having a structure similar to that of the transistor 450 shown in the first embodiment is used. Here is an example of applying the register.

[0250] FIG. 13B shows a photodiode 602 and a transistor 603 in the photosensor. 40, a substrate 601 (element substrate) having an insulating surface is provided as a sensor. A functioning photodiode 602 and transistor 640 are provided. A substrate 613 is provided on the diode 602 and the transistor 640 using an adhesive layer 608. It is being done.

[0251] An insulating film 632, a planarization film 633, and a planarization film 634 are provided over the transistor 640. The photodiode 602 has an electrode 641b formed on the planarization film 633 and an electrode A first semiconductor film 606a, a second semiconductor film 606b, and a and a third semiconductor film 606c, and a planarization film 634. an electrode 642 electrically connected to the electrode 641b via a conductive layer; , and an electrode 641a electrically connected to the electrode 642.

[0252] The electrode 641b is electrically connected to the conductive film 643 formed on the planarizing film 634. 42 is electrically connected to the conductive film 645 via the electrode 641a. The photodiode 602 is electrically connected to the gate electrode of the transistor 640. It is electrically connected to the transistor 640 .

[0253] Here, the first semiconductor film 606a is a semiconductor film having a p-type conductivity, and the second semiconductor film The conductive film 606b is a high-resistance semiconductor film (i-type semiconductor film), and the third semiconductor film 606c is a 1 shows an example of a pin-type photodiode in which a semiconductor film having n-type conductivity is stacked. .

[0254] The first semiconductor film 606a is a p-type semiconductor film, and is made of aluminum containing an impurity element that imparts p-type conductivity. The first semiconductor film 606a can be formed of a ruthenium silicon film. Plasma CV is performed using semiconductor material gas containing Group 3 impurity elements (e.g., boron (B)). It is formed by the D method. Silane (SiH4) can be used as the semiconductor material gas. Alternatively, Si2H6, SiH2Cl2, SiHCl3, SiCl4, SiF4, etc. may be used. In addition, after forming an amorphous silicon film that does not contain impurity elements, An impurity element may be introduced into the amorphous silicon film by ion implantation. By introducing impurity elements by a method such as a method of heating, the impurity elements can be diffused. In this case, the amorphous silicon film can be formed by LPCVD, vapor phase deposition, or the like. The first semiconductor film 606a may be formed by a deposition method, a sputtering method, or the like. It is preferable to form the film so that the thickness is between 100 nm and 50 nm.

[0255] The second semiconductor film 606b is an i-type semiconductor film (intrinsic semiconductor film) and is made of amorphous silicon. The second semiconductor film 606b is formed by using a semiconductor material gas. The amorphous silicon film is formed by plasma CVD. The semiconductor material gases are: Silane (SiH4) can be used. Alternatively, Si2H6, SiH2Cl2, or SiHCl 3, SiCl4, SiF4, etc. may also be used. The second semiconductor film 606b is formed by LPC The second semiconductor film 606b may be formed by a VD method, a vapor deposition method, a sputtering method, or the like. It is preferable that the film thickness is formed to be 200 nm or more and 1000 nm or less.

[0256] The third semiconductor film 606c is an n-type semiconductor film and is an aluminium-based film containing an impurity element that imparts n-type conductivity. The third semiconductor film 606c is formed of an amorphous silicon film. Using semiconductor material gas containing pure elements (e.g., phosphorus (P)), plasma CVD is used. Silane (SiH4) can be used as the semiconductor material gas. H6, SiH2Cl2, SiHCl3, SiCl4, SiF4, etc. may also be used. After forming an amorphous silicon film that does not contain impurity elements, the film is then subjected to diffusion or ion implantation. An impurity element may be introduced into the amorphous silicon film by using an ion implantation method or the like. After the impurity element is introduced, the impurity element may be diffused by heating or the like. In this case, the amorphous silicon film can be formed by LPCVD, vapor phase growth, or The third semiconductor film 606c may be deposited by sputtering or the like. It is preferable to form the film so that the thickness is 00 nm or less.

[0257] In addition, the first semiconductor film 606a, the second semiconductor film 606b, and the third semiconductor film 60 6c may be formed using a polycrystalline semiconductor instead of an amorphous semiconductor. Amorphous (Semi Amorphous Semiconductor: SAS) It may also be formed using a semiconductor.

[0258] In addition, the mobility of holes generated by the photoelectric effect is smaller than that of electrons, so the pin type The photodiode exhibits better characteristics when the p-type semiconductor film side is used as the light receiving surface. The photodiode 60 is formed on the surface of the substrate 601 on which the pin-type photodiode is formed. This example shows how the light received by the semiconductor film 2 is converted into an electrical signal. Since light from the semiconductor film side with a conductive type becomes disturbance light, a conductive film with a light-shielding property is used for the electrode. It is also possible to use the n-type semiconductor film side as the light-receiving surface.

[0259] The insulating film 632, the planarizing film 633, and the planarizing film 634 are made of an insulating material. Depending on the material, sputtering, plasma CVD, spin coating, dipping, spraying - Using coating, droplet ejection method (inkjet method), screen printing, offset printing, etc. The insulating film 632 can be formed similarly to the insulating film 412 in the first embodiment. Use the word "no".

[0260] The planarization films 633 and 634 may be made of, for example, polyimide, acrylic resin, or benzothiazolinone. Uses heat-resistant organic insulating materials such as cyclobutene resin, polyamide, and epoxy resin. In addition to the above organic insulating materials, low dielectric constant materials (low-k materials), Siloxane resin, PSG (phosphorus glass), BPSG (borophosphorus glass), etc. Alternatively, a laminate may be used.

[0261] By detecting the light incident on the photodiode 602, information on the detected object is read. It should be noted that when reading the information of the detected object, a light source such as a backlight is used. It is possible.

[0262] The structures, methods, and the like described in this embodiment may be combined as appropriate with the structures, methods, and the like described in other embodiments. They can be used in combination.

[0263] (Embodiment 7) The semiconductor device disclosed in this specification can be applied to various electronic devices (including gaming machines). The electronic equipment includes a television device (television or television receiver) (also known as computer monitors, digital cameras, digital video cameras, digital Digital photo frames, mobile phones, portable game consoles, portable information terminals, sound reproducing devices, games These electronic devices include gaming machines (pachinko machines, slot machines, etc.) and game cabinets. A specific example is shown in FIG.

[0264] FIG. 14(A) shows a table 9000 having a display section. A display unit 9003 is built into the housing 9001, and images are displayed on the display unit 9003. It is possible to support the housing 9001 with four legs 9002. The housing 9001 also has a power cord 9005 for supplying power.

[0265] The transistor described in any of the above embodiments can be used in the display portion 9003. This makes it possible to provide high reliability to electronic devices.

[0266] The display unit 9003 has a touch input function. By touching the display button 9004 displayed on the screen with a finger or the like, the screen can be operated or information can be input. It also allows communication with other home appliances or allows control of them. It may also be a control device that controls other home appliances by operating the screen. If the semiconductor device having an image sensor function described in embodiment 6 is used, the display portion 9003 It is possible to provide touch input functionality.

[0267] In addition, the screen of the display unit 9003 can be tilted relative to the floor by a hinge provided in the housing 9001. It can also be placed vertically and used as a television set. When a large screen television is installed, the free space becomes narrow, but the table If the display unit is built into the device, the space in the room can be used more effectively.

[0268] FIG. 14(B) shows a television device 9100. The display unit 9103 is incorporated in the housing 9101, and the display unit 9103 displays images. In this example, the housing 9101 is supported by a stand 9105. The figure shows the configuration.

[0269] The television device 9100 can be operated using an operation switch provided on the housing 9101 or a separate remote control. This can be done by using the remote control operation device 9110. The channel and volume can be controlled by the -9109, and the information displayed on the display 9103 In addition, the remote control unit 9110 can be used to control the video. A display unit 9107 for displaying information output from the device 9110 may be provided.

[0270] A television device 9100 shown in FIG. 14(B) includes a receiver, a modem, and the like. The television device 9100 can receive general television broadcasts using a receiver. Furthermore, by connecting to a wired or wireless communication network via a modem, It can be directional (from sender to receiver) or bidirectional (between sender and receiver, or between receivers, etc.) ) information communication is also possible.

[0271] The transistor described in any of the above embodiments is used in the display portion 9103 and the display portion 9107. This allows for high reliability in television sets and remote control devices. It is possible.

[0272] FIG. 14C shows a computer, which includes a main body 9201, a housing 9202, a display portion 9203, It includes a keyboard 9204, an external connection port 9205, a pointing device 9206, etc. nothing.

[0273] The transistor described in any of the above embodiments can be used in the display portion 9203. This makes it possible to provide high reliability to the computer.

[0274] Figures 15(A) and 15(B) show foldable tablet terminals. A) is an open state, and the tablet terminal includes a housing 9630, a display unit 9631a, a display display unit 9631b, display mode changeover switch 9034, power switch 9035, power saving It has a mode changeover switch 9036, a fastener 9033, and an operation switch 9038.

[0275] The transistor described in any of the above embodiments is b), making it possible to create a highly reliable tablet-type terminal.

[0276] A part of the display portion 9631a can be used as a touch panel area 9632a. By touching the operation keys 9638, data can be input. In 31a, for example, half of the area has a display function only, and the other half Although the display area 96 has a touch panel function, the display area 96 is not limited to this configuration. The entire area of ​​the display unit 9 may have a touch panel function. The entire surface of 631a is displayed as a keyboard button to serve as a touch panel, and the display part 9631b is displayed. It can be used as a display screen.

[0277] In addition, in the display unit 9631b, as in the display unit 9631a, The area can be used as a touch panel area 9632b. Touch the area where the display switch button 9639 is displayed with your finger or a stylus. This allows keyboard buttons to be displayed on the display portion 9631b.

[0278] In addition, the touch panel area 9632a and the touch panel area 9632b are simultaneously You can also use touch input.

[0279] A display mode changeover switch 9034 is used to change the display orientation, such as portrait or landscape. You can switch between black and white and color display. The switch 9036 is an external switch that is detected by a light sensor built into the tablet terminal. The display brightness can be optimized according to the amount of light. In addition to sensors, other detection devices such as gyros and acceleration sensors that detect tilt are also available. may be incorporated.

[0280] FIG. 15A shows an example in which the display area of ​​the display portion 9631b is the same as that of the display portion 9631a. However, there is no particular limitation, and one size may be different from the other size. The display quality may also differ. For example, one display panel may be able to display a higher resolution image than the other. It may also be used as a rule.

[0281] FIG. 15(B) shows the tablet terminal in a closed state, and the tablet terminal includes a housing 9630 and a solar cell 9631. 15B, the charge / discharge control circuit 96 As an example of 34, a configuration having a battery 9635 and a DC-DC converter 9636 is shown. This shows that.

[0282] In addition, since the tablet device can be folded in half, when not in use, the case 9630 is closed. Therefore, the display portions 9631a and 9631b can be protected. This allows us to provide tablet devices that are highly durable and reliable for long-term use. .

[0283] In addition, the tablet terminals shown in Figures 15(A) and 15(B) are also available in various other formats. Functions that display important information (still images, videos, text images, etc.), calendars, dates, or times Function to display time and other information on the display, and to operate or edit the information displayed on the display by touch input. Touch input function, function to control processing by various software (programs), etc. It can have.

[0284] The solar cell 9633 attached to the surface of the tablet terminal supplies power to the touch panel. The solar cell 9633 can be supplied to a display unit, a video signal processor, or the like. , which can be provided on one or both sides of the housing 9630, and can efficiently charge the battery 9635. If a lithium-ion battery is used as the battery 9635, This has the advantage of enabling miniaturization.

[0285] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. 15B are A block diagram is shown in (C) and explained. Figure 15(C) shows a solar cell 9633, a battery 9635, DC-DC converter 9636, converter 9637, switches SW1 to SW 3. Shows the display unit 9631, battery 9635, and DC-DC converter 96 36, a converter 9637, and switches SW1 to SW3 are configured to control the charge and discharge of the This corresponds to the control circuit 9634.

[0286] First, an example of operation when power is generated by the solar cell 9633 using external light will be described. The power generated by the solar cell is converted into a voltage to charge the battery 9635. The CDC converter 9636 steps up or steps down the voltage. When power is supplied from the solar cell 9633, switch SW1 is turned on and the converter The voltage is increased or decreased by a voltage converter 9637 to the voltage required for the display unit 9631. When not displaying on the display unit 9631, turn SW1 off and SW2 on to discharge the battery. It is sufficient to configure it to charge the battery 9635.

[0287] The solar cell 9633 is shown as an example of a power generating means, but is not particularly limited thereto. , other power generation methods such as piezoelectric elements and thermoelectric conversion elements (Peltier elements) For example, the battery 9635 may be charged wirelessly (contactlessly). It can be combined with a non-contact power transmission module that transmits and receives power and charges, or other charging methods. This may also be configured as follows.

[0288] The structures, methods, and the like described in this embodiment may be combined as appropriate with the structures, methods, and the like described in other embodiments. They can be used in combination. [Example]

[0289] In this embodiment, in the semiconductor device according to the disclosed invention, the source electrode and The results of cross-sectional observation of the step portion of the drain electrode will be explained.

[0290] First, a method for manufacturing a transistor of an example sample will be described.

[0291] First, a gate electrode was formed on a glass substrate. A tungsten film is formed, and a mask is formed on the tungsten film by a photolithography process. A portion of the tungsten film was etched using the mask to form a gate electrode. .

[0292] Next, a gate insulating film was formed on the gate electrode. The silicon nitride film and a silicon oxynitride film having a thickness of 200 nm were stacked. The silicon film was formed by heating 50 sccm of silane and 5000 sccm of nitrogen in the processing chamber of a plasma CVD device. The pressure in the processing chamber was controlled to 60 Pa, and a high frequency power source of 27.12 MHz was used. The silicon oxynitride film was formed by supplying 150 W of power. Nitrogen chloride 3000 sccm was supplied to the processing chamber of the plasma CVD equipment, and the pressure in the processing chamber was set to 4 The pressure was controlled to 0 Pa, and a power of 100 W was supplied using a 27.12 MHz high frequency power supply. The silicon nitride film and the silicon oxynitride film were grown at a substrate temperature of 350°C. It was formed.

[0293] Next, an oxide semiconductor film was formed so as to overlap with the gate electrode with the gate insulating film interposed therebetween. The IGZO film, which is a CAAC-OS film, is formed on the gate insulating film by sputtering. A mask is formed on the IGZO film by a photolithography process, and the I A part of the IGZO film was etched. After that, the etched IGZO film was subjected to heat treatment. In this example, an IGZO film having a thickness of 35 nm was formed. Ta.

[0294] The IGZO film was prepared by sputtering a target of In:Ga:Zn=1:1:1 (atomic ratio). ) target, and 50sccm argon and 50sccm The oxygen was supplied into the processing chamber of the sputtering device, and the pressure in the processing chamber was controlled to 0.6 Pa. The substrate temperature during the formation of the IGZO film was 1 The temperature was set to 70°C.

[0295] Next, heat treatment was performed to release water, hydrogen, and the like from the oxide semiconductor film. After heat treatment at 450°C for 1 hour in a nitrogen atmosphere, Heat treatment was carried out at 50°C for 1 hour.

[0296] Next, a conductive film is formed over the gate insulating film and the oxide semiconductor film, and A mask is formed on the conductive film by a process, and a part of the conductive film is etched using the mask. The source electrode and the drain electrode were formed. The conductive film is a 400 nm thick aluminum film formed on a 50 nm thick tungsten film. A titanium film having a thickness of 100 nm was formed on the aluminum film.

[0297] Next, the substrate is moved into a reduced pressure processing chamber, heated at 220°C, and then filled with dinitrogen monoxide. The substrate was then moved into a processing chamber equipped with a 27.12 M H The oxygen plasma generated by supplying 150 W of high frequency power using a high frequency power supply of The semiconductor film was exposed.

[0298] Next, after the plasma treatment, the oxide semiconductor film and the source An insulating film was formed on the electrode and the drain electrode. The insulating film was formed under four conditions, A1 to A4. The samples formed under the respective conditions were designated as Samples A1 to A4. In all of the samples A1 to A4, the thickness of the insulating film was set to 400 nm.

[0299] Condition 1 is a condition in which a silicon oxynitride film is used as an insulating film, and silane and Nitrous oxide at a flow rate of 4000 sccm was used as the source gas, the pressure in the processing chamber was 40 Pa, and the substrate temperature was The temperature was set to 220°C, and a high-frequency power of 150 W was supplied to parallel plate electrodes. The film density was measured for the entire film by XRR and was found to be 2.26 g / cm 3 in there were.

[0300] Condition 2 is a condition in which a silicon oxynitride film is used as the insulating film, and silane and The source gas was nitrous oxide with a flow rate of 4000 sccm. The pressure in the processing chamber was 200 Pa. Plasma CV was performed with the plate temperature set to 220°C and 1500W of high frequency power supplied to the parallel plate electrodes. The film density was measured by XRR and found to be 2.31 g / cm². m 3 It was.

[0301] Condition 3 is a silicon nitride film used as an insulating film, silane at a flow rate of 50 sccm, The raw material gases were nitrogen at a flow rate of 100 sccm and ammonia at a flow rate of 100 sccm. The pressure was set to 200 Pa, the substrate temperature was set to 220°C, and 1000 W of high frequency power was applied to the parallel plate electrodes. The film was formed by plasma CVD using a supplied current. The film density was measured by XRR. and 2.50g / cm 3 It was.

[0302] Condition 4 is a silicon nitride film used as an insulating film, silane at a flow rate of 200 sccm, and Nitrogen at a flow rate of 1000 sccm and ammonia at a flow rate of 100 sccm were used as raw material gases. The pressure was set to 200 Pa, the substrate temperature to 350°C, and 2000 W of high-frequency power was applied to the parallel plate electrodes. The film was formed by plasma CVD using a supplied source. The film density was measured by XRR. It is set at 2.72 g / cm 3 It was.

[0303] The cross sections of the samples A1 to A4 were observed using a cross-sectional scanning transmission electron microscope (STEM). :Scanning Transmission Electron Microscope Figure 16(A) shows the STEM image of sample A1, and Figure 16(B) shows the STEM image of sample A2. Fig. 17(A) shows the STEM image of sample A2, Fig. 17(B) shows the STEM image of sample A3, and Fig. 17(C) shows the STEM image of sample A. 4 are shown.

[0304] As shown in FIGS. 16(A), 16(B) and 17(A), the source electrode and the drain electrode It was confirmed that a void had occurred in the insulating film covering the lead electrode in the area enclosed by the dotted line in the figure. On the other hand, in FIG. 17(B), the insulating film covering the source electrode and the drain electrode No voids were observed.

[0305] From this, in the samples A1 to A4, the source electrode and the drain electrode are covered with The insulating film has a film density of 2.26 g / cm 3 More than 2.50g / cm 3 If the insulating film is It was shown that voids were formed. [Example]

[0306] In this example, the characteristics of a transistor in which a nitride insulating film is formed on an oxide insulating film are investigated. The measurement results will be explained.

[0307] First, a method for manufacturing a transistor of an example sample will be described.

[0308] As in Example 1, a gate electrode, a gate insulating film, and an oxide semiconductor film were formed on a glass substrate. Then, heat treatment was performed to remove water, hydrogen, and the like contained in the oxide semiconductor film. After heat treatment at 450°C for 1 hour in a nitrogen atmosphere, Heat treatment was carried out at 50°C for 1 hour.

[0309] Next, a conductive film is formed over the gate insulating film and the oxide semiconductor film, and A mask is formed on the conductive film by a process, and a part of the conductive film is etched using the mask. , a source electrode and a drain electrode were formed.

[0310] Next, the substrate is moved into a reduced pressure processing chamber, heated at 220°C, and then filled with dinitrogen monoxide. The substrate was then moved into a processing chamber equipped with a 27.12 M H The oxygen plasma generated by supplying 150 W of high frequency power using a high frequency power supply of The semiconductor film was exposed.

[0311] Up to this point, Example 1 can be taken into consideration.

[0312] Next, after the plasma treatment, the oxide semiconductor film and the source An insulating film was formed on the electrode and the drain electrode. The insulating film was a nitride insulating film on an oxide insulating film. The oxide insulating film is a layered structure in which a first oxide nitride film with a thickness of 50 nm is formed. The silicon nitride film and the second silicon oxynitride film having a thickness of 400 nm were laminated to form the first silicon nitride film.

[0313] The first silicon oxynitride film was prepared by using silane at a flow rate of 30 sccm and SiO2 at a flow rate of 4000 s The source gas was nitrous oxide (NO) of ccm, the pressure in the processing chamber was 40 Pa, and the substrate temperature was 220°C. The film was formed by plasma CVD, in which 150 W of high frequency power was supplied to parallel plate electrodes.

[0314] The second silicon oxynitride film was formed by mixing silane at a flow rate of 160 sccm and SiO2 at a flow rate of 4000 sccm. The source gas was dinitrogen monoxide at 200 sccm, the pressure in the processing chamber was 200 Pa, and the substrate temperature was 220 ℃, and was formed by the plasma CVD method in which 1500 W of high frequency power was supplied to parallel plate electrodes. Under these conditions, the mixture contained more oxygen than the stoichiometric composition, and the mixture was heated to a temperature of 1000°C. This makes it possible to form a silicon oxynitride film from which part of oxygen is released.

[0315] Next, heat treatment was performed to remove water, hydrogen, and the like from the oxide insulating film. The sample was then subjected to a heat treatment at 350° C. for 1 hour in an oxygen atmosphere.

[0316] Next, a nitride insulating film was formed on the oxide insulating film. The nitride insulating film was a 50 nm thick nitride film. The silicon nitride film was formed using silane at a flow rate of 200 sccm and HCl at a flow rate of 100 sccm. Nitrogen at 2000 sccm and ammonia at 100 sccm were used as raw material gases. The pressure was 100 Pa, the substrate temperature was 350°C, and 2000 W of high frequency power was applied to the parallel plate electrodes. The film was formed by plasma CVD using a supply voltage of 100 V.

[0317] Next, a part of the insulating film (oxide insulating film and nitride insulating film) is etched to form a source electrode. Openings were formed to expose portions of the positive and drain electrodes.

[0318] Next, an interlayer insulating film was formed on the insulating film (nitride insulating film). After coating on the insulating film, exposure and development are performed to form a part of the source electrode or drain electrode. An interlayer insulating film having an opening exposing the insulating film was formed. After that, a heat treatment was carried out. The heat treatment was carried out at a temperature of 25 The temperature was set to 0°C and the reaction was carried out in a nitrogen atmosphere for 1 hour.

[0319] Next, a conductive film was formed to connect to a part of the source electrode or the drain electrode. A 100 nm thick ITO film containing silicon oxide was formed by sputtering.

[0320] Through the above steps, the transistor of the example sample was fabricated.

[0321] As a comparative example, the insulating film of the example sample was an oxide insulating film only, and no nitride insulating film was formed. A comparative sample transistor was fabricated that was not treated.

[0322] In the above-mentioned example samples and comparative sample samples, cross sections of the samples were observed using a cross-sectional scanning transmission electron microscope. (STEM:Scanning Transmission Electron Mic The cross section was observed by STEM. Figure 18(A) shows the STEM image of the example sample, and Figure 1 8(B) shows a STEM image of the comparative sample.

[0323] As shown in FIG. 18(A) and FIG. 18(B), a layer covering the source electrode and the drain electrode is formed. The first silicon oxynitride film and the second silicon oxynitride film are surrounded by dotted lines in the figure. It was confirmed that a void was generated in the second portion. No voids are formed in the silicon nitride film on the silicon oxynitride film. It was thus confirmed that the voids were blocked.

[0324] Next, the Vg-Id characteristics of the transistors of the above-mentioned example sample and comparative example sample were measured. .

[0325] As an accelerated life test for evaluating humidity resistance, a pressure cooker test (PCT) In this example, a PCT was conducted at a temperature of 130°C and humidity of 100%. The example sample and the comparative example sample were kept for 1 hour under the conditions of 85% humidity and 0.23 MPa pressure. .

[0326] In the example sample and the comparative example sample, GBT (Gate Bias Temperature In this example, a GBT stress test was performed in a dark environment. Under the conditions of Vg=-30V, Vd=0V, Vs=0V, stress temperature 60℃, no light irradiation, The stress application time was 1 hour. The actual measurement values ​​were for a channel length (L) of 6 μm and a channel The width (W) was 50 μm, and the thickness (Tox) of the oxide film (gate insulating film) was 280 nm.

[0327] FIG. 19(A) shows the results of the GBT stress test for the example sample, and FIG. 19(B) shows the results for the comparative example sample. The results of the GBT stress test of the sample are shown. The dotted line in the figure shows the measurement results before PCT. As a result, the solid line in the figure shows the measurement results after PCT. The horizontal axis shows the measurement results when the drain voltage (Vd: [V]) is 1 V and 10 V. The vertical axis indicates the gate voltage (Vg: [V]), and the vertical axis indicates the drain current (Id: [A]). "Drain voltage (Vd: [V])" is the potential difference between the drain and source with the source as the reference. The gate voltage (Vg: [V]) is the voltage between the gate and source with the source as the reference. It is a position difference.

[0328] As shown in FIG. 19(A), the transistor of the example sample did not change significantly before and after PCT. On the other hand, as shown in FIG. 19(B), the transistor of the comparative sample was It is clear that the threshold value shifts to the negative side after PCT. It was recognized.

[0329] The difference between the example sample and the comparative sample is that a silicon nitride film is formed on the second silicon oxynitride film. Therefore, even after PCT, the effect of the silicon nitride film is such that the characteristics do not change. It was found that it was possible to suppress the amount of movement.

[0330] Therefore, the voids in the silicon oxynitride film are blocked by the silicon nitride film. In addition, stable electrical characteristics and high reliability can be achieved in semiconductor devices using oxide semiconductors. It can be realized. [Example]

[0331] In this example, the difference in the temperature at which a nitride insulating film is formed on an oxide insulating film is The measurement results of the characteristics will be explained below.

[0332] First, a method for manufacturing a transistor of an example sample will be described.

[0333] The example sample was the same as the example sample in Example 2, except that the film formation temperature of the silicon nitride film was set to 220°C. The sample B1 is the same as the sample in Example 2 (the silicon nitride film was formed at a temperature of 350 ° C.) is designated as sample B2.

[0334] The silicon nitride film of sample B1 was prepared by silane at a flow rate of 50 sccm and 5000 sccm. The source gases were nitrogen at 100 m and ammonia at a flow rate of 100 sccm. The pressure in the processing chamber was set to 200 The substrate temperature was set to 220°C, and 1000W of high frequency power was supplied to the parallel plate electrodes. The silicon nitride film of sample B2 was formed by the same method as the nitride film of sample B1. The sample was the same as sample B1 except that the substrate temperature of the silicon film was set to 350°C.

[0335] Next, the Vg-Id characteristics of the transistors of Samples B1 and B2 were measured.

[0336] A pressure cooker test (PCT) was conducted as an accelerated life test for evaluating humidity resistance. In this example, the sample was subjected to PCT under the conditions of a temperature of 130°C, humidity of 85%, and pressure of 0.20 MPa. B1 and sample B2 were held for 1 hour.

[0337] A GBT stress test was carried out on Sample B1 and Sample B2. As a T-stress test, Vg=-30V to 30V, Vd=0V, Vs= The stress was applied at 0V, at a stress temperature of 60°C, without light irradiation, and for 1 hour. The values ​​are channel length (L) 6 μm, channel width (W) 50 μm, oxide film (gate insulating film) The film thickness (Tox) was 280 nm.

[0338] FIG. 20(A1) shows the results of the GBT stress test of sample B1 before PCT, and FIG. 20(A2) shows the results of the GBT stress test of sample B1 before PCT. ) shows the results of the GBT stress test after PCT for sample B1. ,The results of the GBT stress test of sample B2 before PCT are shown in FIG. 20(B2). The results of the GBT stress test after CT are shown in Fig. 20(A1), Fig. 20(A2), Fig. In Figures 20(B1) and 20(B2), when the drain voltage (Vd: [V]) is 1 V, The horizontal axis shows the gate voltage (Vg: [V]) and the vertical axis shows the measurement results at 10V and 10V. is the drain current (Id: [A]) and the field-effect mobility (μFE: [cm 2 / Vs]) 20(A3) and 20(B3) show the PCT results of samples B1 and B2. The amount of change in threshold voltage (ΔVth) and the amount of change in shift value (ΔShift) before and after are shown.

[0339] In this specification, the threshold voltage (Vth) is the gate voltage (Vg: [V]). is the horizontal axis, and the square root of the drain current (Id (1 / 2) :[A]) plotted on the vertical axis The line with the maximum slope, Id (1 / 2) When the tangent of the That is, Id (1 / 2) It is defined as the gate voltage at the intersection with 0 A. In this case, the drain voltage Vd is set to 10 V to calculate the threshold voltage.

[0340] In this specification, the shift value (Shift) is the gate voltage (Vg: [V]). On the curve plotted on the horizontal axis and the logarithm of the drain current (Id: [A]) on the vertical axis, When the tangent of the slope Id is extrapolated, the straight line Id = 1.0 × 10 -12 Intersection with [A] In this specification, the drain voltage Vd is set to 10 V. , and calculate the shift value.

[0341] As shown in Figures 20(A3) and 20(B3), the transformers of Samples B1 and B2 The transistor showed slight changes in threshold voltage and shift value before and after PCT, indicating degradation. It was also confirmed that the temperature of the silicon nitride film was 350°C. The transistor of sample B1 (the silicon nitride film deposition temperature is 220°C) is It was confirmed that the changes in the threshold voltage and shift value were small. [Example]

[0342] In this example, the RBS (Rutherford backscattering) of the silicon nitride film, which is a part of the insulating film, Backscattering Spectrometry (BSCS) analysis results and secondary ions Secondary Ion Mass Spectrometer (SIMS) The evaluation results using the ry method are explained below.

[0343] First, the analyzed samples will be described.

[0344] The sample is a silicon wafer 11 on which a silicon nitride film 12 is formed by plasma CVD. The silicon nitride film 12 was fabricated under two conditions, Condition C1 and Condition C2 (see FIG. 21). The samples formed under the respective conditions were designated as Sample C1 and Sample C2.

[0345] Condition C1 is a condition in which the temperature at which the silicon wafer 11 is held is 220° C. and the flow rate is 50 sccm. Silane, nitrogen at a flow rate of 5000 sccm, and ammonia at a flow rate of 100 sccm were used as raw material gases. The pressure in the processing chamber was set to 200 Pa, and 1000 W of high frequency power was supplied to the parallel plate electrodes. A silicon nitride film 12 having a thickness of 100 nm was formed by plasma CVD.

[0346] Condition C2 is a temperature at which the silicon wafer 11 is held at 350° C. and a flow rate of 200 sccm. silane, nitrogen at a flow rate of 2000 sccm, and ammonia at a flow rate of 100 sccm were used as raw gases. The pressure in the treatment chamber was set to 200 Pa, and 2000 W of high frequency power was supplied to the parallel plate electrodes. A silicon nitride film 12 having a thickness of 300 nm was formed by plasma CVD.

[0347] Samples C1 and C2 were then evaluated, and the RBS results are shown in Table 1.

[0348] [Table 1]

[0349] Sample C1 contains 26.5 atomic % silicon, 45.5 atomic % nitrogen, It was confirmed that the hydrogen content was 28.1 atomic %. 40.0 atomic % of carbon, 49.2 atomic % of nitrogen, and 10.8 atomic % of hydrogen It was confirmed that sample C2 contained ic% of Zn. It was confirmed that the proportion of hydrogen in the composition was reduced.

[0350] Next, the results of the SIMS analysis are shown in FIG.

[0351] Figure 22(A) shows the concentration profiles of hydrogen, oxygen, fluorine, and carbon measured by SIMS for sample C1. The file is shown in Figure 22(B) as the concentration of hydrogen, oxygen, fluorine and carbon by SIMS of sample C2. The intensity profile is shown.

[0352] The details of the SIMS analysis results of FIG. 22 are shown in Table 2.

[0353] [Table 2]

[0354] Sample C1 contains 2.8 × 10 hydrogen atoms. 22 atoms / cm 3 , oxygen is 1.0 × 10 19 atoms / cm 3 , fluorine is 2.3 × 10 19 atoms / cm 3 , carbon is 5.5 x 1 0 18 atoms / cm 3 It was confirmed that sample C2 contained 1. 6×10 22 atoms / cm 3 , oxygen is 6.8 × 10 17 atoms / cm 3 , fluorine is 7.4×10 18 atoms / cm 3 , carbon is 7.4 × 1017 atoms / cm 3 Contains Therefore, similar to the RBS results, sample C2 was found to have the same structure as sample C1. It was confirmed that the proportion of hydrogen in the composition was reduced compared to the sample. C2 has lower concentrations of impurities such as hydrogen, oxygen, fluorine, and carbon than sample C1. was confirmed. [Example]

[0355] In this example, it was verified whether the voids generated in the insulating film act as a path for the penetration of water, hydrogen, etc. The verification was carried out using SIMS.

[0356] First, the sample will be described with reference to Fig. 23. The sample is an oxide semiconductor shown in Fig. 23(A). Sample D1 has an electrode on the semiconductor film, which generates voids, and sample D2 has an oxide semiconductor film on the semiconductor film shown in FIG. Two types of sample were prepared: sample D1, which has no electrodes and no voids; and sample D2, which has no electrodes and no voids.

[0357] A gate insulating film 22 and an oxide semiconductor film 23 are formed on a glass substrate 21, and a heat treatment is performed. This was performed to remove water, hydrogen, and the like from the oxide semiconductor film 23. After heat treatment at 450°C for 1 hour, the specimen was heated at 450°C for 1 hour in a nitrogen and oxygen atmosphere. The heat treatment was carried out.

[0358] Next, a conductive film is formed on the gate insulating film 22 and the oxide semiconductor film 23, and then photolithography is performed. A mask is formed on the conductive film by a lithography process, and a part of the conductive film is etched using the mask. The electrode 24 was formed by etching.

[0359] Next, the substrate is moved into a reduced pressure processing chamber, heated at 220°C, and then filled with dinitrogen monoxide. The substrate was then moved into a processing chamber equipped with a 27.12 M H The oxygen plasma generated by supplying 150 W of high frequency power using a high frequency power supply of The semiconductor film was exposed.

[0360] Up to this point, Example 1 can be taken into consideration.

[0361] Next, after the plasma treatment, the oxide semiconductor film 23 and the An insulating film 27 was formed on the electrode 24. The insulating film 27 was formed by depositing a nitride insulating film on the oxide insulating film 25. The oxide insulating film 25 is a laminated structure in which a first oxide film 26 is formed. A silicon oxynitride film 25a and a second silicon oxynitride film 25b having a thickness of 400 nm are laminated. and formed.

[0362] The first silicon oxynitride film 25a is formed by mixing silane at a flow rate of 30 sccm and HCl at a flow rate of 40 The source gas was nitrous oxide at 0.00 sccm, the pressure in the processing chamber was 40 Pa, and the substrate temperature was 22 Formed by plasma CVD method at 0°C, supplying 150 W of high frequency power to parallel plate electrodes did.

[0363] The second silicon oxynitride film 25b is formed by mixing silane at a flow rate of 160 sccm and HCl at a flow rate of 4 The source gas was nitrous oxide at a flow rate of 0.000 sccm, the pressure in the processing chamber was 200 Pa, and the substrate temperature was The temperature was set to 220°C and a high frequency power of 1500 W was supplied to parallel plate electrodes by the plasma CVD method. Under these conditions, the oxygen content was greater than the stoichiometric composition, and the A silicon oxynitride film from which part of oxygen is released by heat can be formed.

[0364] Next, heat treatment was performed to remove water, hydrogen, and the like from the oxide insulating film. The sample was then subjected to a heat treatment at 350° C. for 1 hour in an oxygen atmosphere.

[0365] Next, a nitride insulating film 26 was formed on the oxide insulating film 25. The nitride insulating film 26 had a thickness of A silicon nitride film of 50 nm was formed. The run was performed with nitrogen at a flow rate of 5000 sccm and ammonia at a flow rate of 100 sccm as the source gas. The pressure in the processing chamber was set to 200 Pa, the substrate temperature to 220°C, and the average high-frequency power was set to 2000 W. The film was formed by plasma CVD using a parallel plate electrode.

[0366] In this way, sample D1 was prepared. Sample D2 was prepared without forming an electrode. (See Figure 23).

[0367] Samples D1 and D2 were subjected to a pressure cooker test (PCT). is PCT, temperature 130℃, humidity 85% (volume ratio of water vapor contained in the gas is H2O Sample D1 and sample D2 were mixed under the conditions of (water):D2O (heavy water) = 4:1 and 2.0 atmospheres (0.20 MPa). and sample D2 were held for 15 hours.

[0368] In this embodiment, the "D atom" expressed in heavy water is a hydrogen atom with a mass number of 2. child( 2 H).

[0369] SIMS analysis was performed using SSDP (Substrate Side Depth Profiler) Using SIMS (backside SIMS measurement), specimens D1 and D2 after the PCT test were The concentrations of H atoms and D atoms in each sample were measured for sample D1 and sample D2.

[0370] Figure 24(A) shows the concentration profiles of H and D atoms measured by SIMS after the PCT test of sample D1. The profile of sample D2 after the PCT test is shown in Fig. 24(B). 24(A) and 24(B) show the concentration profiles of D atoms ( The natural abundance profile shows that the abundance of D atoms is 0.015%. The concentration profile of D atoms present in nature was calculated from the profile of H atoms. Therefore, the amount of D atoms mixed into the sample by the PCT test is different from the measured D atom concentration. This is the difference from the abundance value of D atom concentration.

[0371] When Sample D1 and Sample D2 are compared, as shown in FIG. 24A, the electrode formed on the oxide semiconductor film is The concentration profile of D atoms measured in the oxide semiconductor film is The concentration of D atoms increased to a high level, indicating that a large amount of D atoms were mixed into the oxide semiconductor film. Therefore, sample D1 has poor barrier properties against water (H2O, D2O) from the outside. It was confirmed that: [Explanation of symbols]

[0372] 11 Silicon wafer 12 Silicon nitride film 21 Glass substrate 22 Gate insulating film 23 Oxide semiconductor film 24 electrodes 25 Oxide insulating film 25a First silicon oxynitride film 25b Second silicon oxynitride film 26 Nitride insulating film 27 Insulating film 31 Oxide semiconductor film 32 Oxide insulating film 32a Oxide insulating film 32b Oxide insulating film 400 boards 401 Undercoat insulating film 402 gate electrode 404 Gate insulating film 404a Gate insulating film 404b Gate insulating film 406 Semiconductor Film 407a Conductive film 407b Conductive film 407c conductive film 408a Source electrode 408b Drain electrode 410 Oxide insulating film 410a Oxide insulating film 410b Oxide insulating film 410c oxide insulating film 410d oxide insulating film 410e oxide insulating film 411 Nitride insulating film 412 insulating film 413 Cavity 414 Interlayer insulating film 416 Electrode 450 transistors 510 Oxide insulating film 510a Oxide insulating film 510b Oxide insulating film 511 Nitride insulating film 512 Gate insulating film 530 insulating film 550 transistors 552 gate electrode 560 transistors 570 Transistor 580 transistors 601 Substrate 602 Photodiode 606a Semiconductor film 606b Semiconductor film 606c Semiconductor film 608 Adhesive layer 613 Substrate 632 insulating film 633 Planarization film 634 Planarization film 640 transistors 641a electrode 641b Electrode 642 Electrode 643 Conductive Film 645 Conductive Film 656 Transistor 658 Photodiode reset signal line 659 Gate signal line 671 Photo sensor output signal line 672 Photo sensor reference signal line 901 Circuit Board 902 Pixel section 903 Signal line driver circuit 904 Scanning line driver circuit 905 Sealing material 906 Circuit Board 908 Liquid crystal layer 910 Transistor 911 Transistor 913 Liquid crystal element 915 Connection terminal electrode 915a Connection terminal electrode 915b Connection terminal electrode 916 Terminal electrode 917 Conductive Film 918 FPC 918a FPC 918b FPC 919 Anisotropic conductive agent 921 Interlayer insulating film 922 Gate insulating film 923 Insulating Film 924 insulating film 925 sealing material 930 electrode 931 Electrode 932 Insulating film 933 Insulating Film 935 Spacer 936 Sealing material 941 Electrode 943 Liquid crystal elements 944 insulating film 950 Silicon nitride film 951 Light-emitting layer 955 Connection terminal electrode 960 Bulkhead 963 Light-emitting element 964 Filling material 971 Source electrode 973 Drain electrode 975 Common potential line 977 Common electrode 985 Common potential line 987 Common electrode 9000 tables 9001 Case 9002 Legs 9003 Display section 9004 Display button 9005 Power Cord 9033 Fasteners 9034 Switch 9035 Power Switch 9036 Switch 9038 Operation switch 9100 Television equipment 9101 Housing 9103 Display section 9105 Stand 9107 Display section 9109 Operation key 9110 Remote control device 9201 Main Unit 9202 Housing 9203 Display section 9204 keyboard 9205 External connection port 9206 Pointing Device 9630 chassis 9631 Display section 9631a Display section 9631b Display section 9632a area 9632b area 9633 Solar Cells 9634 Charge / Discharge Control Circuit 9635 Battery 9636 DC / DC Converter 9637 Converter 9638 Operation key 9639 Button

Claims

[Claim 1] a semiconductor film at least partially overlapping with the gate electrode via a gate insulating film; a source electrode and a drain electrode having an area in contact with a part of the upper surface of the semiconductor film; a first insulating film covering the source electrode, the drain electrode, and the semiconductor film, having a void in a step region formed by the source electrode and the drain electrode on the semiconductor film, and containing silicon oxide as a component; a second insulating film containing silicon nitride as a component and provided in contact with the first insulating film so as to fill the voids in the first insulating film.

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