Indication device

Abstract

To provide a display device capable of reducing parasitic capacitance between wires, or a display device with improved display quality, or a display device capable of reducing power consumption.SOLUTION: The display device comprises a signal line, a scan line, a first electrode, a second electrode, a third electrode, a first pixel electrode, a second pixel electrode and a semiconductor film. The signal line intersects the scan line. The first electrode is electrically connected to the signal line. The first electrode has a region overlapping with the scan line. The second electrode faces the first electrode. The third electrode faces the first electrode. The first pixel electrode is electrically connected to the second electrode. The second pixel electrode is electrically connected to the third electrode. The semiconductor film is in contact with the first electrode, the second electrode and the third electrode. The semiconductor film is provided between the scan line and the first electrode through the third electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device. However, one aspect of the present invention is not limited to the above-mentioned technical field. Not specified. The technical field of one aspect of the invention disclosed herein, etc., relates to a product, method, or manufacturing. This relates to a method. Alternatively, one aspect of the present invention relates to a process, machine, or manufacture. This relates to tea, or composition of matter. More specifically, the technical field of one aspect of the present invention disclosed herein includes semiconductor devices, and Display devices, liquid crystal display devices, light-emitting devices, energy storage devices, imaging devices, methods for driving them, or the These manufacturing methods can be given as an example. [Background technology]

[0002] In recent years, liquid crystal display devices have seen improvements in viewing angle characteristics and display quality, including vertical alignment (VA:Ve A liquid crystal display device of the (artificially aligned) type is available. Also, a VA type In a liquid crystal display device, each pixel has multiple pixel electrodes, and each pixel electrode is connected to a pixel A multi-domain liquid crystal display device is provided, which has transistors that control the potential of electrodes. It is being done. By providing multiple pixel electrodes in a single pixel, the orientation of the liquid crystal can be changed by each pixel electrode. Because it is possible to adjust the viewing angle, it offers an even wider viewing angle compared to conventional VA-type liquid crystal displays. It is possible to do this (see Patent Document 1).

[0003] Furthermore, LCD displays tend to have larger screen sizes, with diagonal sizes exceeding 60 inches. Furthermore, development is underway with screen sizes of 120 inches or more in mind. The screen resolution also supports Full HD (FHD, 1920×1080) and 4K ( The trend is toward higher resolution, such as 3840×2160, and the number of pixels is so-called 7680×4320. The development of liquid crystal display devices with 8K high resolution is also being accelerated.

[0004] Furthermore, to reduce afterimages and improve display quality, the drive speed is doubled (also known as double-speed drive). High-speed driving is being implemented, and even faster driving of four times or more speed is being considered. In addition, to realize a three-dimensional (3D) liquid crystal display device, images for the right eye and left eye are required. Because it is necessary to display them alternately, the LCD display is operated at a high speed of 2x or higher. This is required. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2006-317867 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, with the increasing size and resolution of liquid crystal displays, the required number of pixels has increased significantly. This increases the writing time per pixel, thus shortening the writing time per pixel. Therefore, the potential of the pixel electrodes is controlled. Transistors are required to have high-speed operation and high on-current, among other characteristics.

[0007] Furthermore, increased parasitic capacitance between wires can cause delays in signal transmission to the termination of signal lines. As a result, display quality deteriorates, such as uneven display and poor gradation, and power consumption increases. cormorant.

[0008] Therefore, one aspect of the present invention provides a display device that can reduce parasitic capacitance between wiring. This is one of the challenges. Furthermore, one aspect of the present invention provides a display device with improved display quality. This is one of the challenges. Furthermore, one aspect of the present invention provides a display device that can reduce power consumption. One of the challenges is to achieve this. Alternatively, one aspect of the present invention relates to a novel semiconductor device, or a novel The objective is to provide a display device and the like.

[0009] Furthermore, the description of these problems does not preclude the existence of other problems. One approach does not necessarily need to solve all of these problems. The title will become clear from the description in the specification, drawings, claims, etc. It is possible to extract other issues from the descriptions in the drawings, claims, etc. [Means for solving the problem]

[0010] One aspect of the present invention includes a signal line, a scanning line that intersects the signal line, and a signal line that is electrically connected to the signal line. A first electrode, a second electrode facing the first electrode, and a third electrode facing the first electrode. Then, the first pixel electrode is electrically connected to the second electrode, and the third electrode is electrically connected to the first pixel electrode. The second pixel electrode is in contact with the first to third electrodes, and the scanning line is in contact with the first to third electrodes. The first electrode has a semiconductor film provided between it and a third electrode, and the region overlapping with the scan line is This is a device characterized by having [a certain feature].

[0011] Furthermore, in one aspect of the present invention, a gate insulating film is provided between the scanning line and the semiconductor film, and the scanning line The first transistor is composed of a gate insulating film, a semiconductor film, a first electrode, and a second electrode. The second trace is formed by the scanning line, gate insulating film, semiconductor film, first electrode, and third electrode. The display device is characterized by comprising a generator.

[0012] Furthermore, in one aspect of the present invention, a first capacitive wiring is electrically connected to the first pixel electrode, and It has a second capacitive wiring electrically connected to the 2 pixel electrodes, and the signal line is connected to the first pixel electrode The signal line comprises a region overlapping between the first and second pixel electrodes, and the signal line comprises a first capacitive wiring and a second capacitive wiring. The display device is characterized by not having an area that overlaps with wiring.

[0013] Furthermore, in one aspect of the present invention, the first electrode has an upper surface shape that is connected to the second electrode and the third electrode. The display device is characterized by being provided between poles.

[0014] Furthermore, in one aspect of the present invention, the semiconductor film is In, M (where M is aluminum, gallium, i) The display device, characterized by containing an oxide having thorium or tin and Zn. That is the case.

[0015] Furthermore, in one aspect of the present invention, the semiconductor film comprises a first semiconductor film and an area overlapping the first semiconductor film. A second semiconductor film comprising a region, wherein the first semiconductor film is more than the second semiconductor film, In The display device contains an oxide whose atomic ratio is greater than that of M. [Effects of the Invention]

[0016] By applying one aspect of the present invention, parasitic capacitance between the wiring of a display device can be reduced. Furthermore, by applying one aspect of the present invention, the display quality of the display device can be improved. It is possible. Furthermore, by applying one aspect of the present invention, the power consumption of the display device can be reduced. It is possible. Alternatively, by applying one aspect of the present invention, a novel semiconductor device or a novel display can be created. Display devices and the like can be provided. Note that the description of these effects does not preclude the existence of other effects. It's not something to give away.

[0017] Furthermore, one aspect of the present invention does not necessarily have to possess all of these effects. Any other effects will become clear from the description in the specification, drawings, claims, etc. It is possible to extract other effects from descriptions such as specifications, drawings, and claims. be. [Brief explanation of the drawing]

[0018] [Figure 1] A top view and circuit diagram of one aspect of a pixel. [Figure 2] A top view and circuit diagram of a pixel illustrating one aspect of the present invention. [Figure 3] A top view and circuit diagram of one aspect of a pixel. [Figure 4] A cross-sectional view of one aspect of a pixel. [Figure 5] A top view of one aspect of a pixel. [Figure 6] A top view of one aspect of a pixel. [Figure 7] A top view and circuit diagram of one aspect of a pixel. [Figure 8] A top view and circuit diagram of one aspect of a pixel. [Figure 9] A cross-sectional view of one aspect of a pixel. [Figure 10] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 11] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 12] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 13] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 14] A cross-sectional view showing an example of the semiconductor device manufacturing process, a top view and a cross-sectional view showing one aspect of the semiconductor device. [Figure 15] A cross-sectional view showing one aspect of a semiconductor device. [Figure 16] A top view and a cross-sectional view showing one embodiment of a semiconductor device. [Figure 17] A cross-sectional view showing one aspect of a semiconductor device. [Figure 18] A diagram illustrating the band structure. [Figure 19] High-resolution TEM image with Cs correction in cross-section of CAAC-OS, and schematic cross-sectional diagram of CAAC-OS. [Figure 20] High-resolution TEM image with Cs correction in the plane of CAAC-OS. [Figure 21] A diagram illustrating the XRD structural analysis of CAAC-OS and single-crystal oxide semiconductors. [Figure 22] A figure showing the electron diffraction pattern of CAAC-OS. [Figure 23] A diagram showing the changes in the crystalline structure of In-Ga-Zn oxide due to electron irradiation. [Figure 24] A top view showing one embodiment of a display device. [Figure 25] A cross-sectional view showing one embodiment of a display device. [Figure 26] A cross-sectional view showing one embodiment of a display device. [Figure 27] A diagram illustrating the display module. [Figure 28] A diagram illustrating electronic devices. [Modes for carrying out the invention]

[0019] Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is described below This invention is not limited to the description thereof. Without departing from the spirit and scope of the present invention, It is easily understood by those skilled in the art that the form and details can be changed in various ways. Therefore, the present invention shall be interpreted as being limited only to the embodiments described below. There is none. Furthermore, when explaining the configuration of the present invention using drawings, the same reference numerals refer to different things. It is used consistently across different drawings.

[0020] In this specification, the terms 1st, 2nd, 3rd, through nth (where n is a natural number) are used in a specific sense. This is added to avoid confusion regarding the constituent elements and does not mean that the number is limited. do.

[0021] Furthermore, the words "membrane" and "layer" can be used interchangeably depending on the context or situation. Accordingly, they can be interchanged. For example, the term "conductive layer" can be replaced with "conductive layer". In some cases, the term can be changed to "film." Or, for example, "insulating film." In some cases, it may be possible to change the term to "insulating layer."

[0022] (Embodiment 1) In this embodiment, the configuration of a single pixel in a liquid crystal display device will be explained using Figures 1 to 9. do.

[0023] Figure 1(A) shows one pixel 100 of a multi-domain liquid crystal display device shown in this embodiment. This is a top view, and the circuit diagram of pixel 100 shown in Figure 1(A) is shown in Figure 1(B). Also, Figure 2( A) is a top view of one pixel 200 of a conventional multi-domain liquid crystal display device, as shown in Figure 2. The circuit diagram of the pixel shown in (A) is shown in Figure 2(B).

[0024] As shown in Figures 1(A) and 1(B), pixel 100 is located on scan line 103 and scan line 10 It has a signal line 121 that intersects with 3. It also has a capacitive wiring that extends in the same direction as the scan line 103. It has capacitive wiring 105a and capacitive wiring 105b. There is a scan line 103 between them.

[0025] Furthermore, near the intersection of scan line 103 and signal line 121, transistor 136 and transistor It has a st 137. Transistor 136 has a semiconductor film 135 superimposed on scan line 103 and The first electrode has a first electrode 123 and a second electrode 125a superimposed on the semiconductor film 135. Electrode 123 is electrically connected to signal line 121. The first electrode 123 is a transistor In 136, it functions as either the source electrode or the drain electrode. Second electrode 125a This component functions as the other of the source electrode and drain electrode in transistor 136.

[0026] Transistor 137 has a semiconductor film 135 superimposed on the scan line 103, and semiconductor film 135 and It has a superimposed first electrode 123 and a third electrode 125b. The first electrode 123 is In the lampistor 137, it functions as one of the source electrode and drain electrode. The third electric Electrode 125b serves as the other of the source electrode and drain electrode in transistor 137. To be able to.

[0027] In Figure 1(A), in the top surface shape, a portion of the edge of the semiconductor film 135 is used as a gate electrode. Transistors 136 and 137 are located outside the functioning scan line 103. However, this is not the only example. As shown in Figure 1(C), the transient of pixel 100 In sta 136 and transistor 137, the edge of the semiconductor film 135 is at the edge of scan line 103. It can be located inside the section.

[0028] The second electrode 125a included in transistor 136 connects to the pixel electrode via aperture 144a. It is electrically connected to 139a. That is, transistor 136 is connected to the second electrode 125a It is connected to the liquid crystal element 142, which includes the pixel electrode 139a. Also, one of the electrodes of the capacitive element 140 The pole is electrically connected to the pixel electrode 139a and the second electrode 125a of the transistor 136. The other electrode is electrically connected to the capacitive wiring 105a (see Figure 1(B)).

[0029] The third electrode 125b included in transistor 137 is connected to the pixel electrode via aperture 144b. It is electrically connected to 139b. That is, transistor 137 is connected to the third electrode 125b It is connected to the liquid crystal element 143, which includes the pixel electrode 139b. Also, one of the electrodes of the capacitive element 141 The pole is electrically connected to the pixel electrode 139b and the third electrode 125b of the transistor 137. The other electrode is electrically connected to the capacitive wiring 105b (see Figure 1(B)).

[0030] Furthermore, openings 144a and 144b are provided in the insulating film 116, which will be described later. Furthermore, in order to avoid making the drawings complicated, in Figures 1(A) and 2(A), the pixel electrodes are shown. Hatching is not applied to 139a and pixel electrode 139b; only the outline of the top surface shape is shown with a dashed line. They are doing it.

[0031] Transistors 136 and 137 are located approximately in the center of pixel 100 in the top surface shape. It is located between the pixel electrodes 139a and 139b of each subpixel in pixel 100. It is formed in this way.

[0032] One aspect of the present invention comprises a signal line 121, a scan line 103, a first electrode 123, and a second electrode Electrode 125a, third electrode 125b, first pixel electrode 139a, second pixel electrode 13 The signal line 121, which has 9b and a semiconductor film 135, intersects with the scan line 103 and the first electrode 123 is electrically connected to signal line 121, and the first electrode 125a overlaps with scan line 103. It has a region to be folded, the second electrode 125a is opposite the first electrode 123, and the third electrode 12 5b faces the first electrode 123, and the first pixel electrode 139a faces the second electrode 125a. The second pixel electrode 139b is electrically connected to the third electrode 125b, The semiconductor film 135 is in contact with the first electrode 123, the second electrode 125a, and the third electrode 125b. The semiconductor film 135 is formed between the scan line 103 and the first electrode 123 to the third electrode 125b. It is a display device that is placed in between.

[0033] Furthermore, it has a gate insulating film 107, a transistor 136, and a transistor 137. The gate insulating film 107 is positioned between the scan line 103 and the semiconductor film 135, and the transient T136 consists of scan line 103, gate insulating film 107, semiconductor film 135, first electrode 123, The transistor 137 is equipped with a second electrode 125a and a scan line 103 and a gate insulating film 1 07, the display device comprising a semiconductor film 135, a first electrode 123, and a third electrode 125b This is also one aspect of the present invention.

[0034] Transistors 136 and 137 have a source electrode and a drain electrode on one side. A certain first electrode 123 is common, and the first electrode 123 overlaps with the scan line 103. With this configuration, in one pixel 100 that constitutes the display device, the transient Parasitic fluid generated between one electrode of transistor 136 and transistor 137 and scan line 103 The amount can be reduced.

[0035] Furthermore, as shown in Figure 1(B), in transistor 136, scan line 103 and Parasitic capacitance C1 is generated in the superimposed portion of electrode 125a of transistor 2. Also, transistor 137 In this case, parasitic capacitance C2 is generated in the overlapping portion of scan line 103 and the third electrode 125b. Also, the signal line 121 and the scan line 103, the capacitive wiring 105a and the capacitive wiring 105b In the overlapping regions, parasitic capacities C5, C6, and C7 are generated, respectively. do.

[0036] Here, as a comparative example, each of the two transistors in a single pixel is connected to a signal line and an electric Figure 2 shows a top view of pixel 200, where the electrodes connected electrically are different and the electrodes do not overlap with the scan lines. (A) is shown. The circuit diagram of pixel 200 is also shown in Figure 2(B). In configurations similar to pixel 100, the same reference numerals are used, and the explanation of the configuration is omitted.

[0037] As shown in Figure 2(B), pixel 200 is located on scan line 203 and the signal that intersects scan line 203. It has line 221. Also, capacitive wiring 105a and capacity extending in the same direction as scan line 203. It has a capacitance wiring 105b. Furthermore, between the capacitance wiring 105a and the capacitance wiring 105b, a scanning It has line 203.

[0038] Furthermore, near the intersection of scan line 203 and signal line 221, transistor 236 and transistor It has a transistor 237. Transistor 236 has a gate electrode protruding from scan line 203, The fourth electrode 223a protruding from the signal line 221 and the second electrode connected to the liquid crystal element 142 It has an electrode 125a. In addition, one electrode of the capacitive element 140 is included in the liquid crystal element 142. The pixel electrode 139a and the second electrode 125a of the transistor 236 are electrically connected. The other electrode of the capacitive element 140 is electrically connected to the capacitive wiring 105a (see Figure 2(B)). Light. ).

[0039] Transistor 237 has a gate electrode protruding from scan line 203 and a protruding from signal line 121. It has a fifth electrode 223b that extends outwards and a third electrode 125b that is connected to the liquid crystal element 143. Furthermore, one electrode of the capacitive element 141 is connected to the pixel electrode 139b included in the liquid crystal element 143. And electrically connected to the third electrode 125b of transistor 237, in addition to the capacitive element 141. The electrode is electrically connected to the capacitive wiring 105b (see Figure 2(B)).

[0040] Transistors 236 and 237 are the source electrode and drain electrode, respectively. One of the points having the fourth electrode 223a and the fifth electrode 223b is located in the pixel 100. It is different from transistors 136 and 137. Also, it protrudes from signal line 221. The fourth electrode 223a and the fifth electrode 223b do not overlap with the scan line 203.

[0041] In addition, in transistor 236, the overlapping portion of scan line 203 and second electrode 125a Parasitic capacitance C11 occurs in this area. Also, the superposition of scan line 203 and the fourth electrode 223a Parasitic capacitance C13 occurs in the part. In transistor 237, scan line 203 and Parasitic capacitance C12 is generated in the superimposed area of ​​the third electrode 125b. Also, scan line 203 Parasitic capacitance C14 is generated in the superposition area of ​​the fifth electrode 223b. Also, signal line 22 In the overlapping portion of 1 and scan line 203, capacitive wiring 105a and capacitive wiring 105b, Then, parasitic capacities C15, C16, and C17 are generated, respectively.

[0042] In transistors 136 and 236, scan line 103 and second electrode 1 The area of ​​the overlapping portion of 25a is approximately the same as the area of ​​the overlapping portion of the scan line 203 and the second electrode 125a. If it is 1, then parasitic capacitances C1 and C11 are approximately the same. Also, transistor 13 In transistors 7 and 237, the surface of the overlapping portion of scan line 103 and the third electrode 125b If the product and the area of ​​the overlapping region of scan line 203 and the third electrode 125b are approximately the same, then parasitic Capacitance C2 and parasitic capacitance C12 are approximately the same. Also, the overlap of signal line 121 and scan line 103 If the area of ​​the tatami mat and the area of ​​the overlapping portion of signal line 221 and scan line 203 are approximately the same, then parasitic Capacitance C5 and parasitic capacitance C15 are approximately the same. Also, signal line 121 and capacitance wiring 105a If the area of ​​the overlapping portion of the signal line 221 and the area of ​​the overlapping portion of the capacitance wiring 105a are approximately the same, Parasitic capacitances C6 and C16 are approximately the same. Also, signal line 121 and capacitance wiring The area of ​​the overlapping portion of 105b is approximately the same as the area of ​​the overlapping portion of the signal line 221 and the capacitance wiring 105b. If the value is 1, then the parasitic capacity C7 and parasitic capacity C17 are approximately the same.

[0043] In the comparative example, pixel 200, transistors 236 and 237, The source electrode and the drain electrode are different electrodes (in transistor 236) In the case of transistor 237, this is the fourth electrode 223a, and in the case of transistor 237, it is the fifth electrode 223b. Therefore, a parasitic capacitance C13 is generated between the scan line 203 and the fourth electrode 223a, and the scan line 203 A parasitic capacitance C14 is generated between the first and fifth electrodes 223b.

[0044] However, in the pixel 100 shown in this embodiment, transistor 136 and transistor The electrode that will be either the source electrode or the drain electrode in sta 137 (first electrode 123) The electrodes are common to both the signal line 121 and the scan line 103, and the electrode is in the overlapping portion of the signal line 121 and the scan line 103. They are superimposed. For this reason, in transistors 136 and 137, the electrodes and running The parasitic capacity generated in the overlapping portion of line 103 is included in the parasitic capacity C5 described above. Since the capacitance C5 is almost identical to the parasitic capacitance C15, compared to 200 pixels, 100 pixels Therefore, the parasitic capacity is less by the amount of parasitic capacity C13 and parasitic capacity C14. A display device according to one aspect of the present invention reduces parasitic capacitance generated between wirings in one pixel 100. It can be reduced.

[0045] In this embodiment, the pixel 100 is composed of transistors 136 and 137 In this context, because they have a common semiconductor film, transistors 136 and 137 In this configuration, the region in contact between the first electrode 123 and the semiconductor film 135 can be shared. As a result, the area occupied by transistors 136 and 137 in pixel 100 is reduced. It is possible to reduce it.

[0046] Furthermore, as shown in Figures 3(A) and 3(B), in pixel 100, capacitive wiring 105 The configuration may also involve sharing a and capacitive wiring 105b with adjacent pixels. This configuration reduces the number of capacitive wirings required by the display device. Also, see Figure 3. As shown in (A), the area of ​​the overlapping portion of the pixel electrode 139a and the capacitive wiring 105a is increased. This makes it possible to increase the capacitance of the capacitive element 140. Similarly, the pixel electrode 139b and By increasing the area of ​​the overlapping portion of the capacitance wiring 105b, the capacitance of the capacitance element 141 can be increased. It is possible.

[0047] Next, the structure of the transistor and capacitive elements in pixel 100 will be explained using Figure 4. I will reveal it.

[0048] Figure 4 shows transistor 136 and capacitive element 1 along the dashed line AB shown in Figure 1(A). It has a 40-section cross-sectional structure.

[0049] Transistor 136 has a scan line 103 and a semiconductor film 135 on the substrate 101, and scan line A gate insulating film 107 is provided between 103 and the semiconductor film 135, and contacts the semiconductor film 135. It has a first electrode 123 and a second electrode 125a that is in contact with the semiconductor film 135.

[0050] The capacitive element 140 has a capacitive wiring 105a and a second electrode 125a on the substrate 101, and It has a gate insulating film 107 provided between the wiring 105a and the second electrode 125a. .

[0051] Furthermore, the gate insulating film 107, the semiconductor film 135, the first electrode 123, and the second electrode 12 An insulating film 116 is provided on 5a. Also, on the insulating film 116, The pixel electrode 139a is electrically connected to the second electrode 125a through the opening 144a. It will be established.

[0052] Although not shown in the diagram, transistor 137 has a similar structure to transistor 136. Furthermore, the capacitive element 141 is constructed with the same structure as the capacitive element 140.

[0053] The substrate 101 can be a glass substrate, a ceramic substrate, or a substrate that can withstand the processing temperature of this manufacturing process. A plastic substrate with sufficient heat resistance can be used. If the property is not required, an insulating film can be applied to the surface of a metal substrate such as stainless steel. This is also good. Examples of glass substrates include barium borosilicate glass and aluminoborosilicate glass. It is preferable to use an alkali-free glass substrate such as glass or aluminosilicate glass. There are no limitations on the size of the substrate 101; for example, third-generation or first-generation substrates commonly used in liquid crystal displays can be used. A 0th generation glass substrate can be used. Also, as the material used for the substrate 101, In form 2, you can refer to the material used for the substrate 502, which will be described later.

[0054] A portion of scan line 103 functions as the gate electrode of transistor 136. Scan line 103 It is molybdenum, titanium, chromium, tantalum, tungsten, aluminum, copper, neodymium Using metallic materials such as chromium, scandium, and nickel, or alloy materials that mainly consist of these materials It can be formed as a single layer or in layers. Furthermore, impurity elements such as phosphorus can be doped into it. Semiconductors such as polycrystalline silicon, Ag-Pd-Cu alloys, Al-Nd alloys, Al -Ni alloys may also be used.

[0055] For example, as a two-layer stacked structure of scan line 103, a molybdenum film is placed on top of an aluminum film. A laminated structure consisting of two layers, or a two-layer structure in which a molybdenum film is laminated on a copper film, or a copper film A two-layer structure with a titanium nitride film or tantalum nitride film laminated on top, titanium nitride film and molybdenum A two-layer structure consisting of a copper-magnesium alloy film and a copper film, or a two-layer structure consisting of a copper-magnesium alloy film containing oxygen and a copper film. Structure: A two-layer structure consisting of a copper-manganese alloy film containing oxygen and a copper film. It is preferable to have a two-layer structure in which a copper film is laminated with a tan. Gusten film or tungsten nitride film and aluminum-silicon alloy film or aluminum This involves creating a three-layer structure consisting of a titanium-titanium alloy film and a titanium nitride film or titanium film. This is preferable. A metal film that functions as a barrier film is laminated on a film with low electrical resistance. Therefore, the electrical resistance can be reduced, and the diffusion of metal elements from the metal film to the semiconductor film can be prevented. This can be done. Also, as the material used for the scanning line 103, the conductive film 5 described later in Embodiment 2 can be used. You can refer to the materials used in 04.

[0056] Furthermore, the capacitive wiring 105a and capacitive wiring 105b are made of the same material and laminate as the scanning line 103. It has a structure.

[0057] The gate insulating film 107 is a silicon oxide film, a silicon oxide nitride film, a silicon nitride film, and a silicon nitride film. Silicon oxide film, aluminum oxide film, aluminum nitride film, aluminum oxide nitride film, Alternatively, an aluminum nitride film can be formed as a single layer or in multiple layers. In this configuration, the gate insulating film 107 is the product of gate insulating film 107a and gate insulating film 107b It has a layered structure. Also, the materials used for gate insulating film 107a and gate insulating film 107b As for the materials used for insulating film 506 and insulating film 507, which will be described later in Embodiment 2, You can refer to the fees.

[0058] As the semiconductor film 135, a silicon film or an oxide semiconductor film can be used. The conductive film 135 may have an amorphous structure, a polycrystalline structure, a single-crystal structure, or other crystalline structures as appropriate. It is possible.

[0059] In particular, an oxide semiconductor film can be suitably used as the semiconductor film 135. Specifically In-M (where M is aluminum, gallium, yttrium, or tin) oxide, I nM-Zn oxide can be used. In particular, the semiconductor film 135 can be composed of It is preferable to use different oxide semiconductor films 135a and 135b. The materials used for the oxide semiconductor film 135a and the oxide semiconductor film 135b are, respectively, The materials used in the oxide semiconductor film 508a and oxide semiconductor film 508b described later in the second method of application You can refer to the fees.

[0060] The first electrode 123 and the second electrode 125a are made of aluminum, copper, titanium, neodymium, A single layer made of scandium, molybdenum, chromium, tantalum, or tungsten, Alternatively, aluminum can be formed by lamination. It may also be formed from an alloy (such as an Al-Nd alloy that can be used for scanning line 103). Crystalline silicon with donor impurity elements added may also be used. The film in contact with the element-doped crystalline silicon is made of titanium, tantalum, molybdenum, and Formed from sten or nitrides of these elements, with aluminum or aluminum on top. A laminated structure formed by aluminum alloy may also be used. Furthermore, aluminum or aluminum The upper and lower surfaces of the alloy are made of titanium, tantalum, molybdenum, tungsten, or these materials. A laminated structure sandwiched between elemental nitrides may also be used. Furthermore, the first electrode 123 and the second electrode 1 The materials used for 25a are conductive film 512a and conductive film 51, which will be described later in Embodiment 2. You can refer to the materials for 2b.

[0061] Furthermore, the signal line 121 and the third electrode 125b are made of the same material and components as the first electrode 123. It has a layered structure.

[0062] In this embodiment, the insulating film 116 consists of insulating film 116a, insulating film 116b, and insulating film 116 It has a layered structure of c. Used for insulating film 116a, insulating film 116b, and insulating film 116c. The materials and forming methods are as follows: insulating film 514 and insulating film 5, which will be described later in Embodiment 2. You can refer to the descriptions of 16 and insulating film 518. Also, insulating film 116 is gate insulating film 107 and It may also be formed in a single layer or in layers using similar materials.

[0063] The pixel electrode 139a is made of molybdenum, titanium, tantalum, tungsten, aluminum, Metal films such as silver, copper, chromium, neodymium, scandium, etc., or alloys containing these metals. Gold films and the like can be used in single or multilayer forms. As for alloys containing aluminum, Aluminum-nickel-lanthanum alloy, aluminum-titanium alloy, aluminum-neodymium alloy Examples include silver alloys. Also, examples of silver-containing alloys include silver-neodymium alloys and magnesium alloys. Examples include nesium-silver alloys. Additionally, alloys containing gold and copper can be used. Furthermore, using metal nitride films containing titanium nitride, molybdenum nitride, tungsten nitride, etc. It is also possible to use the following materials for the pixel electrode 139a. The material of the film 520 can be referenced. The pixel electrode 139b is made of the same material as the pixel electrode 139a. It has a layered structure.

[0064] Alternatively, an oxide semiconductor film may be used as the pixel electrode. Figure 5 shows the case where an oxide semiconductor film is used. Figure 6 shows a top view of a pixel 100 having pixel electrodes 148 and 149. This is the cross-sectional structure of transistor 136 and capacitance element 145 along the dashed line CD shown. .

[0065] In this specification, the oxide conductive film is an oxide semiconductor with high carrier density and low resistance. This can be rephrased as a conductive film, an oxide semiconductor film having conductivity, or an oxide semiconductor film with high conductivity, etc. It is also possible to obtain it.

[0066] By using an oxide semiconductor film as the pixel electrode 148, the semiconductor film 135 is made of an oxide semiconductor film. When a conductive film is used, the semiconductor film 135 and the pixel electrode 148 can be formed by the same process. This is preferable. Oxide semiconductor films have oxygen vacancies in the film or / or hydrogen, water, etc. The resistance can be controlled by the concentration of the pure substance. Therefore, each is processed into an island shape. Treatment of an oxide semiconductor film that increases oxygen vacancies or / and impurity concentration, or oxygen vacancies or / and By selecting a process that reduces the concentration of impurities, the semi-finished product formed by the same process can be processed in a way that reduces impurity levels. The resistivity of the conductive film 135 and the pixel electrode 148 can be controlled.

[0067] Specifically, the oxide conductive film 148a and oxide conductor function as pixel electrodes 148 Plasma treatment is performed on the island-shaped oxide semiconductor film that will become film 148b, and oxygen in the oxide semiconductor film Increasing defects, or / or increasing impurities such as hydrogen and water in oxide semiconductor films. This allows for the creation of oxide semiconductor films with high carrier density and low resistance. On the other hand, On the rangistar 136, oxide semiconductor films 135a and 135b are exposed to the plasma treatment described above. Insulating films 116a and 116b are provided to prevent this from happening. In Figure 6, insulating films 116a and In 116b, the region overlapping with the oxide conductive films 148a and 148b is selectively removed. It is designed in that way.

[0068] Typical plasma treatments performed on oxide conductive films 148a and 148b include rare gas Selected from among s(He, Ne, Ar, Kr, Xe), phosphorus, boron, hydrogen, and nitrogen. Plasma treatment using a gas containing one or more of the following is an example. More specifically, under an Ar atmosphere. Plasma treatment in a mixed gas atmosphere of Ar and hydrogen, ammonia atmosphere Plasma treatment under the following conditions, plasma treatment under a mixed gas atmosphere of Ar and ammonia, or nitrogen Examples include plasma processing under atmospheric conditions.

[0069] Furthermore, the pixel electrode 149 has the same material and layered structure as the pixel electrode 148. In the pixel 100 shown in Figures 5 and 6, the capacitive element 145 has a capacitive wiring 105a and a pixel electrical A gate insulating film 107 is provided between the pole 148 and the capacitive wiring 105a and the pixel electrode 148. It has the following. Furthermore, the capacitive element 146 has a capacitive wiring 105b, a pixel electrode 149, and a capacitive wiring It has a gate insulating film 107 provided between the line 105b and the pixel electrode 149.

[0070] For more detailed information on the configuration and manufacturing method of transistor 136, please refer to Embodiment 2. This will be described later. The pixel 100 described in this embodiment uses the transistor shown in Embodiment 2. This makes it possible to reduce the power consumption of the display device according to one aspect of the present invention.

[0071] [Differential examples of pixel configuration] The following describes the structure of a single pixel having a different structure from the pixel 100 described above in a liquid crystal display device. The process will be explained using Figures 7 to 9.

[0072] Figure 7(A) shows one pixel 30 of the multi-domain liquid crystal display device shown in this embodiment. Figure 7(B) is a top view of 0, and Figure 7(A) is a circuit diagram of pixel 300 shown in Figure 7(A).

[0073] As shown in Figures 7(A) and 7(B), pixel 300 is located on scan line 303 and scan line 30 It has a signal line 321 that intersects with 3. The signal line 321 is connected to the pixel electrode 339a and the pixel electrode It includes an area that overlaps with the space between 339b. Also, capacitive wiring 3 extends in the same direction as signal line 321. It has 05a and capacitive wiring 305b. That is, signal line 321 has capacitive wiring 305a and It does not have an area that overlaps with capacitive wiring 305b. b is electrically connected to pixel electrode 339a and pixel electrode 339b, respectively. A signal line 321 is provided between the capacitance wiring 305a and the capacitance wiring 305b.

[0074] Furthermore, near the intersection of scan line 303 and signal line 321, transistor 336 and transistor It has a st 337. Transistor 336 has a semiconductor film 335 superimposed on scan line 303 and It has a sixth electrode 323a and a seventh electrode 325a superimposed on the semiconductor film 335. The sixth electrode 323a is electrically connected to the signal line 321. The sixth electrode 323a is connected to the traction control line. It functions as one of the source and drain electrodes in the converter 336. 7th electrode 325a functions as the source electrode and the other drain electrode in transistor 336. do.

[0075] Transistor 337 has a semiconductor film 335 superimposed on the scan line 303, and semiconductor film 335 and It has superimposed eighth electrode 323b and ninth electrode 325b. The eighth electrode 323b is It is electrically connected to signal line 321. The eighth electrode 323b is connected to transistor 337. It functions as one of the source electrode and the drain electrode. The ninth electrode 325b is a transistor In the ZISTRA 337, it functions as the other of the source electrode and drain electrode.

[0076] The seventh electrode 325a included in transistor 336 is connected to the pixel electrode via aperture 344a. It is electrically connected to 339a. That is, transistor 336 is connected to the seventh electrode 325a. It is connected to the liquid crystal element 342 which includes the pixel electrode 339a. Also, one side of the capacitive element 340 The electrodes are electrically connected to the pixel electrode 339a and the seventh electrode 325a of the transistor 336. The other electrode 345a is electrically connected to the capacitive wiring 305a via the opening 346a. .

[0077] The ninth electrode 325b included in transistor 337 is connected to the pixel electrode via aperture 344b. It is electrically connected to 339b. That is, transistor 337 is connected to the ninth electrode 325b. It is connected to the liquid crystal element 343 which includes the pixel electrode 339b. Also, one side of the capacitive element 341 The electrode is electrically connected to the pixel electrode 339b and the ninth electrode 325b of the transistor 337. The other electrode 345b is electrically connected to the capacitive wiring 305b via the opening 346b. .

[0078] Furthermore, openings 344a and 344b are provided in the insulating film 316, which will be described later. The openings 346a and 346b are provided in the gate insulating film 307, which will be described later. To avoid making the drawing complicated, in Figure 7(A), the pixel electrode 339a and the pixel electrode Pole 339b does not have hatching, and only the outline of the top surface shape is shown with a dashed line.

[0079] Transistors 336 and 337 are located approximately in the center of pixel 300 in the top surface shape. It is located between the pixel electrodes 339a and 339b of each subpixel in pixel 300. It is formed in this way.

[0080] In transistors 336 and 337, the source electrode and the drain electrode are respectively The sixth electrode 323a and the eighth electrode 323b, which are one of the electrodes, are connected to the signal line 321 and the running line In the overlapping portion of scan line 303, it overlaps with scan line 303. With this configuration, the table In one pixel 300 that constitutes the display element, transistor 336 and transistor 337 This reduces the parasitic capacitance that occurs between one electrode and the scanning line 303. In transistors 336 and 337, the source electrode and the drain electrode are respectively The other electrodes, the seventh electrode 325a and the ninth electrode 325b, are superimposed on the scan line 303. do.

[0081] Furthermore, as shown in Figure 7(B), in transistor 336, scan line 303 and Parasitic capacitance C21 occurs in the superimposed portion of electrode 325a of 7. Also, transistor 33 In 7, the parasitic capacitance C22 is in the overlapping portion of the electrodes 325b of scan line 303 and 9. It occurs. Also, in the overlapping portion of signal line 321 and scan line 303, parasitic capacitance C25 occurs. The sixth electrode 323a and the eighth electrode 323b are connected to the signal line 321 and the scan line 303. In the overlapping area, the sixth electrode 323a and the eighth electrode 32 overlap with the scan line 303. The parasitic capacitance generated in the overlapping area of ​​3b and scan line 303 is included in the parasitic capacitance C25 described above. It can be done.

[0082] Here, a pixel 300 having transistors 336 and 337, and Compare with the pixel 100 having the sta 136 and transistor 137. Seventh electrode 325 The area of ​​the overlapping portion of a and scan line 303 is equal to the area of ​​the overlapping portion of the second electrode 125a and scan line 103. Because it is larger than the area, the parasitic capacitance C21 is larger than the parasitic capacitance C1. Also, the 9th electrode 3 The area of ​​the overlapping portion of 25b and scan line 303 is the overlapping portion of the third electrode 125b and scan line 103. Because it is larger than the area of ​​the part, the parasitic capacitance C22 is larger than the parasitic capacitance C2. Also, scan line 3 Area of ​​the overlapping portion of 03 and signal line 321, and area of ​​the overlapping portion of scan line 103 and signal line 121 If and are approximately identical, then the parasitic capacity C25 and parasitic capacity C5 are approximately identical.

[0083] Furthermore, at pixel 100, the signal line 121 and the capacitance wiring 105a and capacitance wiring 105b overlap. Parasitic capacitances C6 and C7 occur in the tatami area, respectively. Meanwhile, at pixel 300... Therefore, signal line 321 does not have an area that overlaps with capacitive wiring 305a and capacitive wiring 305b. Therefore, parasitic capacitance occurs between signal line 321 and capacitive wiring 305a and capacitive wiring 305b. do not have.

[0084] In a liquid crystal display device having multiple pixels, a delay in signal transmission via signal lines occurs. Parasitic capacitance occurs more at the termination of the signal transmission path than through the transistor. However, the impact on signal transmission delay is small. For example, in pixel 100, signal line 121 and The parasitic capacitance C6 generated in the overlapping portion with the quantitative wiring 105a is greater than that of the scan line 103 and the second electrode. The parasitic capacitance C1 that occurs in the overlapping portion with 125a has a greater impact on the delay of signal transmission on signal line 121. The impact is small. This is because the number of capacitive wirings superimposed on a single signal line 121 in a liquid crystal display device. While the parasitic capacitance C6 is added and affects signal transmission, the parasitic capacitance C1 is only one signal When one transistor 136 connected to line 121 is turned ON, it affects signal transmission. This is to give. From this, compared to pixel 100, pixel 300 has parasitic Only the difference between capacity C21 and parasitic capacity C1, and the difference between parasitic capacity C22 and parasitic capacity C2. Although large, parasitic capacitances C6 and C7 that occur at pixel 100 do not occur. This reduces the parasitic capacitance that causes delays in signal transmission in the signal lines of liquid crystal display devices. It is possible.

[0085] As shown in Figure 7(C), the edge of the semiconductor film 335 is in the direction in which the signal line 321 extends. Extending, the superposition of the seventh electrode 325a and the scan line 303, and the ninth electrode 325b and The seventh electrode 325a and the ninth electrode 3 are positioned so that the area of ​​the overlapping portion of scan line 303 is reduced. 25b may be provided. With this configuration, the parasitic capacity C21 and parasitic capacity described above The capacitance C22 can be reduced. Also, as shown in Figure 7(D), the top view shows The edge of the semiconductor film 335 is positioned outside the overlapping area of ​​scan line 321 and scan line 303. A conductive film 335 may be provided. Between the signal line 321 and the scan line 303, a gate insulating film is provided. By forming a semiconductor film 335 in addition to 307, the signal line 321 and scan line 303 are superimposed. In some cases, it may be possible to reduce the amount of parasitic organisms that develop in the area.

[0086] Furthermore, as shown in Figures 8(A) and 8(B), in pixel 300, capacitive wiring 305 The configuration may also involve sharing a and capacitive wiring 305b with adjacent pixels. This configuration reduces the number of capacitive wirings required by the display device. Also, see Figure 8. As shown in (A), the area of ​​the overlapping portion of the pixel electrode 339a and the capacitive wiring 305a is increased. This makes it possible to increase the capacitance of the capacitive element 340. Similarly, the pixel electrode 339b and By increasing the area of ​​the overlapping portion of the capacitance wiring 305b, the capacitance of the capacitance element 341 can be increased. It is possible.

[0087] Next, the structure of the transistor and capacitive elements in pixel 300 will be explained using Figure 9. I will reveal it.

[0088] Figure 9 shows transistor 336 and capacitive element 3 in the dashed-dotted line CD shown in Figure 7(A). It has a 40-section cross-sectional structure.

[0089] Transistor 336 has a scan line 303 and a semiconductor film 335 on the substrate 301, and scan line A gate insulating film 307 is provided between 303 and the semiconductor film 335, and contacts the semiconductor film 335. It has a sixth electrode 323a and a seventh electrode 325a that is in contact with the semiconductor film 335.

[0090] The capacitive element 340 has an electrode 345a, a seventh electrode 325a, and an electrode 3 on the substrate 301. It has a gate insulating film 307 provided between 45a and the seventh electrode 325a.

[0091] Furthermore, on the gate insulating film 307, through the opening 346a provided in the gate insulating film 307 A capacitive wiring 305a is provided which is electrically connected to electrode 345a. Gate insulating film 30 7. On the semiconductor film 335, the sixth electrode 323a, the seventh electrode 325a and the capacitive wiring 305a An insulating film 316 is provided thereon. An opening 344 is provided in the insulating film 316. A pixel electrode 339a is provided which is electrically connected to the seventh electrode 325a via a.

[0092] Although not shown in the diagram, transistor 337 has a similar structure to transistor 336. Furthermore, the capacitive element 341 is constructed with the same structure as the capacitive element 340.

[0093] Each layer constituting transistor 336 and capacitive element 340 consists of transistor 136 and The insulating film 316 and The pixel electrode 339a is made of the same material as the insulating film 116 and the pixel electrode 139a, respectively. It can be used. Also, the electrode 345a and the capacitance wiring 305a are respectively The same material as that used for the probe 303 and the sixth electrode 323a can be used.

[0094] For more detailed information on the configuration and manufacturing method of transistor 336, please refer to Embodiment 2. This will be described later. The pixel 300 described in this embodiment uses the transistor shown in Embodiment 2. This makes it possible to reduce the power consumption of the display device according to one aspect of the present invention.

[0095] Having the pixel 100 or pixel 300 described in this embodiment allows for multi-domain The structure of the liquid crystal display device is such that the gate electrodes of the transistors are located between the scan lines and signal lines. Between the scanning line and the signal line which is one of the source and drain electrodes of the transistor, The amount of parasitic capacity produced can be reduced. Also, the pixel 300 described in this embodiment As a result, the multi-domain structure of the liquid crystal display device generates between the signal line and the capacitive wiring. Parasitic capacitance can be reduced. This makes it possible to use large liquid crystal displays and high-speed drives. In liquid crystal display devices, and high-resolution liquid crystal display devices, the display quality can be improved. Furthermore, it can reduce the power consumption of the liquid crystal display device.

[0096] In this embodiment, a structure is shown in which two transistors are provided in one pixel. , but not limited to this. A single pixel has three or more transistors and said transistors It may have multiple connected pixel electrodes.

[0097] The configuration shown in this embodiment may be used in appropriate combination with the configurations shown in other embodiments. It is possible. (Embodiment 2) In this embodiment, a semiconductor device and a method for manufacturing a semiconductor device according to one aspect of the present invention are described below. This will be explained with reference to Figures 10 to 18.

[0098] <Example 1 of semiconductor device configuration> Figure 14(C) is a top view of a transistor 500, which is a semiconductor device according to one aspect of the present invention. Figure 14(B) is a cross-sectional view of the section between the dashed line X1 and X2 shown in Figure 14(C). This corresponds to the cross-sectional view of the section between the dashed line Y1 and Y2. Also, Figure 10(A) Figure 14(A) is a cross-sectional view illustrating the manufacturing process of transistor 500 shown in Figure 14(B). That is the case.

[0099] Furthermore, in Figure 14(C), in order to avoid complexity, the structure of transistor 500 is Some of the components (such as the insulating film that functions as a gate insulating film) are omitted from the illustration. The direction of the dashed line X1-X2 is the channel length direction, and the direction of the dashed line Y1-Y2 is the channel width direction. It may be referred to as such. Furthermore, in the top view of the transistor, the same term will be used in subsequent drawings. Similar to 14(C), parts of components may be omitted and illustrated.

[0100] The transistor 500 includes a conductive film 504 that functions as a gate electrode on a substrate 502, a dielectric film 506 on the substrate 502 and the conductive film 504, a dielectric film 507 on the dielectric film 506, an oxide semiconductor film 508 on the dielectric film 507, a conductive film 512a that functions as a source electrode electrically connected to the oxide semiconductor film 508, and a conductive film 512b that functions as a drain electrode electrically connected to the oxide semiconductor film 508. Also, on the transistor 500, more specifically, dielectric films 514, 516, and a dielectric film 518 are provided on the conductive films 512a, 512b, and the oxide semiconductor film 508. The dielectric films 514, 516, 518 function as protective dielectric films for the transistor 500. Note that the dielectric film 514 may be referred to as the first protective dielectric film, and the dielectric film 516 may be referred to as the second protective dielectric film.

[0101] Also, the oxide semiconductor film 508 includes a first oxide semiconductor film 508a on the side of the conductive film 504 that functions as a gate electrode, and a second oxide semiconductor film 508b on the first oxide semiconductor film 508a. Further, the dielectric films 506 and 507 function as gate insulating films for the transistor 500.

[0102] As the oxide semiconductor film 508, In-M (where M is aluminum, gallium, yttrium, or tin) oxide, In-M-Zn oxide can be used. In particular, it is preferable to use In-M-Zn oxide as the oxide semiconductor film 508.

[0103] Also, the first oxide semiconductor film 508a has more In ​​​​​​​​​It is preferable to include an oxide composition in which the atomic ratio of is greater than the atomic ratio of M.

[0104] The first oxide semiconductor film 508a is composed such that the atomic ratio of In is greater than the atomic ratio of M. And so, the field-effect mobility of transistor 500 (sometimes simply called mobility or μFE) The field effect mobility of transistor 500 can be increased. Specifically, the field effect mobility of transistor 500 can be increased to 10 cm 2 The field-effect mobility of transistor 500 is greater than / Vs, and more preferably 30c. m 2 It becomes possible to exceed / Vs.

[0105] For example, a transistor with high field-effect mobility as described above can be used to generate a gate signal. Driver (especially the demultiplex connected to the output terminal of the shift register of the gate driver) By using it in a Plexor, a semiconductor or display device with a narrow bezel (also called a narrow bezel) can be created. We can provide this.

[0106] On the other hand, the first oxide semiconductor film 508a has a composition in which the atomic ratio of In is greater than the atomic ratio of M. This makes the electrical characteristics of transistor 500 more prone to fluctuations when light is irradiated. However, However, in a semiconductor device according to one aspect of the present invention, a second oxide semiconductor film is placed on the first oxide semiconductor film 508a. A second oxide semiconductor film 508b is formed. Because the composition has a lower atomic ratio of In than the oxide semiconductor film 508a, the first oxide semiconductor The band gap Eg is larger than that of the conductive film 508a. Therefore, the first oxide semiconductor The oxide semiconductor film 50 has a stacked structure consisting of a body film 508a and a second oxide semiconductor film 508b. 8 shows increased resistance to light-negative bias stress testing.

[0107] By using the above configuration for the oxide semiconductor film, the light of the oxide semiconductor film 508 during light irradiation The amount of absorption can be reduced. Therefore, the transistor 500 during light irradiation This can suppress fluctuations in electrical characteristics.

[0108] Furthermore, when an oxygen vacancy is formed in the oxide semiconductor film 508 of the transistor 500 Electrons, which act as carriers, are generated, making it easy for the transistor to exhibit normally-on characteristics. The normally-on characteristic is that when the gate voltage Vg = 0V, the current (for example, drain) is... - This refers to the characteristic of current (Ids) flowing between the source and the source. Therefore, oxide semiconductor film 508 Reducing oxygen vacancies, especially in the first oxide semiconductor film 508a, is important for stability. This is also important for obtaining the transistor characteristics. Therefore, one aspect of the present invention is a transistor In this configuration, the insulating film on the oxide semiconductor film 508, here, the oxide semiconductor film 508 By introducing excess oxygen into the insulating film 514 and / or insulating film 516, insulating film 514 and / or transfer oxygen from the insulating film 516 into the oxide semiconductor film 508, and the oxide semiconductor film In 508, in particular, oxygen vacancies in the first oxide semiconductor film 508a are filled. Alternatively, insulating film When forming the first barrier film 531 on 516, excess oxygen in the insulating film 516 By introducing this, oxygen is moved from the insulating film 516 to the oxide semiconductor film 508, and the oxide semiconductor film In 508, in particular, oxygen vacancies in the first oxide semiconductor film 508a are filled.

[0109] Furthermore, the insulating films 514 and 516 contain an excess of oxygen compared to their stoichiometric composition. It is more preferable to have a region (oxygen-rich region). In other words, insulating films 514 and 516 , which is an insulating film capable of releasing oxygen. In addition, to provide an oxygen-excess region in the insulating films 514 and 516, for example, oxygen is introduced into the insulating films 514 and 516 after film formation to form an oxygen-excess region. As a method for introducing oxygen, an ion implantation method, an ion doping method, a plasma immersion ion implantation method, plasma treatment, or the like can be used. Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. In addition, to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, the second oxide semiconductor film 508b preferably has high oxygen permeability. By using the second oxide semiconductor film 508b having high oxygen permeability, the excess oxygen contained in the insulating films 514 and 516 can be suitably permeated into the first oxide semiconductor film 508a. Thus, in the semiconductor device according to one aspect of the present invention, by forming the oxide semiconductor film in a stacked structure and including excess oxygen in the insulating film in contact with the oxide semiconductor film, a highly reliable semiconductor device can be provided. Further, in one aspect of the present invention, the temperature during the manufacturing process of the semiconductor device having the above structure can be lowered (typically less than 400 °C or less than 375 °C (preferably 340 °C or more and 360 °C or less)). The manufacturing process of the semiconductor device will be described later.

[0110] Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. nm or less, and more preferably 3 nm or more and 10 nm or less.

[0111] Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. Also, in order to compensate for the oxygen deficiency in the first oxide semiconductor film 508a, it is preferable to reduce the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b. For example, the film thickness in the vicinity of the channel region of the second oxide semiconductor film 508b is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less.

[0112] Thus, in the semiconductor device according to one aspect of the present invention, by forming the oxide semiconductor film in a stacked structure and including excess oxygen in the insulating film in contact with the oxide semiconductor film, a highly reliable semiconductor device can be provided. ​​​​​​​​​​​​The following describes in detail the other components included in the semiconductor device of this embodiment. do.

[0114] <Circuit board> There are no major restrictions on the material of substrate 502, but it should at least be able to withstand subsequent heat treatment. It must have heat resistance. For example, glass substrates, ceramic substrates, quartz substrates, etc. A fire substrate or the like may be used as substrate 502. Alternatively, silicon or silicon carbide may be used as the material. Single-crystal semiconductor substrates, polycrystalline semiconductor substrates, and compound semiconductors such as silicon germanium are used as materials. It is also possible to apply substrates, SOI substrates, etc., and semiconductor elements are provided on these substrates. The prepared material may be used as substrate 502. Note that a glass substrate may be used as substrate 502. If available, use large-area substrates such as 6th, 7th, 8th, 9th, and 10th generation substrates. By doing so, large-scale display devices can be manufactured. This is preferable because it can reduce manufacturing costs.

[0115] Furthermore, a flexible substrate is used as the substrate 502, and the transistor 50 is directly mounted on the flexible substrate. A 0 may be formed. Alternatively, a release layer may be provided between the substrate 502 and the transistor 500. Good. The delamination layer is applied to the substrate 502 after the semiconductor device has been partially or completely completed on it. It can be separated and transferred to another substrate. In this case, transistor 500 is subjected to It can be transferred to substrates with poor thermal resistance or flexible substrates.

[0116] <Conductive film that functions as gate electrode, source electrode, and drain electrode> Conductive film 504 functions as a gate electrode, and conductive film 512 functions as a source electrode. a) and the conductive film 512b that functions as a drain electrode are chromium (Cr) and copper (C) u), aluminum (Al), gold (Au), silver (Ag), zinc (Zn), molybdenum (M) o), tantalum (Ta), titanium (Ti), tungsten (W), manganese (Mn), ni Metallic elements selected from Ni (Ni), Fe (Fe), and Cobalt (Co), or the above-mentioned elements. Using alloys composed of metallic elements, or alloys combining the aforementioned metallic elements, It can be formed.

[0117] Furthermore, the conductive films 504, 512a, and 512b can be single-layer or multi-layer structures of two or more layers. This may also be the case. For example, a single-layer structure of an aluminum film containing silicon, or a titanium film on an aluminum film. A two-layer structure in which a titanium film is stacked, a two-layer structure in which a titanium film is stacked on top of a titanium nitride film, titanium nitride film A two-layer structure with a tungsten film laminated on top, or a tantalum nitride film or tungsten nitride film on top A two-layer structure consisting of stacked tungsten films, a titanium film, and an aluminum film stacked on top of the titanium film. There are also three-layer structures, such as one in which layers are formed, and then a titanium film is formed on top of that. Choose from tan, tantalum, tungsten, molybdenum, chromium, neodymium, and scandium. One or more alloy films or nitride films may be used.

[0118] Furthermore, conductive films 504, 512a, and 512b contain indium tin oxide and tungsten oxide. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide Apply a light-transmitting conductive material such as indium tin oxide with added silicon oxide. It is also possible.

[0119] Furthermore, conductive films 504, 512a, and 512b contain Cu-X alloy films (where X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti may be used. A Cu-X alloy film is used. This allows for processing using a wet etching process, thus reducing manufacturing costs. It becomes possible.

[0120] <Gate insulating film, Refurbished insulating film> Insulating films 506 and 507 function as gate insulating films for transistor 500. So, plasma chemical vapor deposition (PECVD) Acid Silicon oxide film, silicon oxide nitride film, silicon nitride oxide film, silicon nitride film, aluminum oxide Nium film, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide Films, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film and ne Insulating films containing one or more odium films can be used. Instead of a laminated structure of insulating film 507, a single insulating film selected from the above materials, or 3 Multiple insulating films may be used.

[0121] Furthermore, the insulating film 506 functions as a blocking film that suppresses oxygen permeation. For example, excess acid in insulating films 507, 114, 516 and / or oxide semiconductor film 508 When a component is supplied, the insulating film 506 can suppress the permeation of oxygen.

[0122] Furthermore, the oxide semiconductor film 508, which functions as the channel region of transistor 500, is in contact with the transistor 500. The insulating film 507 is preferably an oxide insulating film, and is preferably composed of an excess of acid in a stoichiometric composition. It is more preferable to have a region containing elements (oxygen-rich region). In other words, insulating film 5 07 is an insulating film capable of releasing oxygen. Note that the insulating film 507 has an oxygen-rich region. To provide this, for example, an insulating film 507 can be formed in an oxygen atmosphere. Alternatively, a film can be deposited. Oxygen may be introduced into the insulating film 507 to form an oxygen-rich region. Method of introducing oxygen and For example, ion implantation, ion doping, plasma immersion ion implantation, and Zuma treatment and other similar processes can be used.

[0123] Furthermore, when hafnium oxide is used as the insulating film 507, the following effects are achieved. Hafnium has a higher dielectric constant than silicon oxide or silicon oxide / nitride. Therefore, Compared to cases using silicon oxide or silicon oxide nitride, the film thickness of insulating film 507 can be increased. Therefore, the leakage current due to tunnel current can be reduced. In other words, off-electric This makes it possible to realize transistors with low current. Furthermore, hafni oxide with a crystalline structure Um has a higher dielectric constant compared to hafnium oxide, which has an amorphous structure. Therefore To create a transistor with a low off-current, hafnium oxide with a crystalline structure is used. It is preferable that it be present. Examples of crystal structures include monoclinic and cubic systems. However, one aspect of the present invention is not limited to these.

[0124] In this embodiment, a silicon nitride film is formed as the insulating film 506, and the insulating film 507 It forms a silicon oxide film. Compared to the silicon oxide film, the silicon nitride film has a relative dielectric constant. Because the rate is high and the thickness required to obtain capacitance equivalent to that of a silicon oxide film is large, By including a silicon nitride film as the gate insulating film of ZISTA 500, the insulating film is physically made thicker. This can be done. Therefore, the decrease in the dielectric strength of transistor 500 is suppressed, and furthermore, the dielectric strength can be reduced. By improving the edge breakdown voltage, electrostatic discharge (ESD) breakdown of transistor 500 can be suppressed.

[0125] <Oxide semiconductor film> The oxide semiconductor film 508 can be the material shown above. If 508 is In-M-Zn oxide, the s used to deposit the In-M-Zn oxide film is... The atomic ratio of the metal elements in the puttering target should preferably satisfy In≧M and Zn≧M. It seems so. As for the atomic ratio of metal elements in such a sputtering target, In:M: Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:3, I A preferred ratio is n:M:Zn=3:1:2 and In:M:Zn=4:2:4.1. Also, oxides are preferred. When the semiconductor film 508 is In-M-Zn oxide, the sputtering target is multi It is preferable to use a target containing crystalline In-M-Zn oxide. By using a target containing Zn oxide, a crystalline oxide semiconductor film 508 is formed. This makes it easier to achieve. Furthermore, the atomic ratios of the oxide semiconductor film 508 to be formed are determined by the error and The atomic ratio of the metal elements contained in the above sputtering target is plus or minus 4. Includes 0% variation. For example, as a sputtering target, if the atomic ratio is In:Ga: When using Zn=4:2:4.1, the atomic ratio of the oxide semiconductor film 508 to be deposited is I There are cases where the neighboring properties of n:Ga:Zn are 4:2:3.

[0126] For example, the first oxide semiconductor film 508a is the aforementioned In:M:Zn=2:1:3 、Use sputtering targets such as In:M:Zn = 3:1:2 and In:M:Zn = 4:2:4.1 for formation. Preferably, the first oxide semiconductor film 508a has an atomic ratio of In:M:Zn = 4:α1 (1.5 ≤ α1 ≤ 2.5):α2 (2.5 ≤ α2 ≤ 3.5).

[0127] Also, for the second oxide semiconductor film 508b, use sputtering targets such as In:M:Zn = 1:1:1 and In:M:Zn = 1:1:1.2 for formation. Preferably, the second oxide semiconductor film 508b has an atomic ratio of In:M:Zn = 1:β1 (0.8 ≤ β1 ≤ 1.2):β2 (0.8 ≤ β2 ≤ 1.2). Note that for the atomic ratio of the metal elements in the sputtering target used for the second oxide semiconductor film 508b, it is not necessary to satisfy In ≥ M and Zn ≥ M, and a composition satisfying In < M and / or Zn < M may also be used. Specifically, examples include In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, and In:M:Zn = 1:3:6.

[0128] Also, the oxide semiconductor film 508 has an energy gap of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. By using an oxide semiconductor with a wide energy gap in this way, the off-current of the transistor 500 can be reduced. In particular, for the first oxide semiconductor film 508a, use an oxide semiconductor film with an energy gap of 2.0 eV or more, preferably 2.0 eV or more and 3.0 eV or less, and for the second oxide semiconductor film 508b, use an oxide semiconductor film with an energy gap of 2.5 eV or more and 3.5 eV or less. ​​​​​​​​​​​​​​​It is suitable. Also, it is preferable that the energy gap of the second oxide semiconductor film 508b is larger than that of the first oxide semiconductor film 508a. It is preferable that the energy gap of the second oxide semiconductor film 508b is larger than that of the first oxide semiconductor film 508a.

[0129] Also, the thicknesses of the first oxide semiconductor film 508a and the second oxide semiconductor film 508b are each 3 nm or more and 200 nm or less, preferably 3 nm or more and 100 nm or less, more preferably 3 nm or more and 50 nm or less.

[0130] Also, as the first oxide semiconductor film 508a, an oxide semiconductor film with a low carrier density is used. For example, the carrier density of the first oxide semiconductor film 508a is 8×10 11 / cm 3 less than, preferably 1×10 11 / cm 3 less than, more preferably 1×10 10 / cm 3 less than, and 1×10 -9 / cm 3 or more is sufficient. Also, as the second oxide semiconductor film 508b, an oxide semiconductor film with a low carrier density is used. For example, the carrier density of the second oxide semiconductor film 508b is 1×10 / cm 17 / cm 3 or less, preferably 1×10 15 / cm 3 or less, more preferably 1×10 13 / cm 3 or less, even more preferably 1×10 11 / cm 3 or less is sufficient.

[0131] Note that it is not limited to these, and those with an appropriate composition may be used according to the required semiconductor characteristics and electrical characteristics (field effect mobility, threshold voltage, etc.) of the transistor. Also, according to the requirements To obtain the semiconductor characteristics of the transistor, a first oxide semiconductor film 508a and a second Carrier density, impurity concentration, defect density, and atoms of metal elements and oxygen in oxide semiconductor film 508b It is preferable to use appropriate numerical ratios, interatomic distances, densities, etc.

[0132] The first oxide semiconductor film 508a and the second oxide semiconductor film 508b are as follows: By using oxide semiconductor films with low impurity concentrations and low defect level densities, further improvements can be made. It is preferable that transistors with excellent electrical characteristics can be fabricated. Here, impurities High-purity intrinsic or substantially high-purity materials are characterized by low concentration and low defect level density (few oxygen vacancies). This is called high-purity intrinsic. Oxide semiconductor films that are high-purity intrinsic or substantially high-purity intrinsic are called Because there are few rear sources, the carrier density can be lowered. Therefore, the oxide In transistors where a channel region is formed in a semiconductor film, the threshold voltage becomes negative. It rarely exhibits atmospheric properties (also known as normally-on). Furthermore, it is of high purity and is essentially pure. Oxide semiconductor films, which are inherently high-purity and intrinsic, have a low defect level density, and therefore a low trap level density. It may be lower. Also, high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor films It has a remarkably low off-current and a channel width of 1 × 10⁻⁶ 6 A channel with a length L of 10 μm in μm Even with a device, the voltage between the source electrode and the drain electrode (drain voltage) is between 1V and 10V. Within the range, the off-current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1 ×10 -13 It is possible to obtain the characteristic of being A or less.

[0133] Therefore, channels can be channeled into the above-mentioned high-purity intrinsic, or substantially high-purity intrinsic oxide semiconductor film. Transistors in which a region is formed exhibit small fluctuations in electrical characteristics and are highly reliable transistors. This can be done. Furthermore, the charge trapped in the trap levels of the oxide semiconductor film disappears. The time required to do so is long, and it can sometimes behave as if it were a fixed charge. Therefore, A transistor in which a channel region is formed in an oxide semiconductor film with a high trap level density is an electric transistor. The gas properties may become unstable. Impurities include hydrogen, nitrogen, alkali metals, or Alkaline earth metals are among them.

[0134] The hydrogen contained in the oxide semiconductor film reacts with the oxygen bonded to the metal atoms to form water. This forms an oxygen vacancy in the lattice (or the part from which oxygen has been removed). When hydrogen enters, electrons, which act as carriers, are sometimes generated. Also, some of the hydrogen It can combine with oxygen atoms that bond with metal atoms to generate electrons, which act as carriers. Transistors using oxide semiconductor films containing hydrogen exhibit normally-on characteristics. It is inexpensive. For this reason, it is preferable that the oxide semiconductor film 508 has as little hydrogen as possible. Specifically, in oxide semiconductor film 508, the hydrogen concentration obtained by SIMS analysis is Degrees, 2 × 10 20 atoms / cm 3 The following is preferably 5 × 10 19 atoms / cm 3 More preferably 1 × 10 19 atoms / cm 3 Below, 5 x 10 18 atoms / cm 3 The following is preferably 1 × 10 18 atoms / cm 3 The following is more convenient: 5x1 0 17 atoms / cm 3More preferably 1 × 10 16 atoms / cm 3 below Let's assume that.

[0135] Furthermore, the first oxide semiconductor film 508a has a higher hydrogen concentration than the second oxide semiconductor film 508b. It is preferable to have a portion with a low degree of oxidation. The first oxide semiconductor film 508a is preferable to the second oxide Having regions with lower hydrogen concentrations than the monocrystalline semiconductor film 508b results in a highly reliable semiconductor. It can be used as a device.

[0136] Furthermore, in the first oxide semiconductor film 508a, silicon, which is one of the Group 14 elements, and When carbon is present, oxygen vacancies increase in the first oxide semiconductor film 508a, leading to n-type formation. Therefore, the concentrations of silicon and carbon in the first oxide semiconductor film 508a, The concentration of silicon and carbon near the interface with the first oxide semiconductor film 508a (by SIMS analysis) The concentration obtained is 2 × 10 18 atoms / cm 3 The following is preferably 2 × 10 17 a toms / cm 3 The following applies:

[0137] Furthermore, in the first oxide semiconductor film 508a, alkali obtained by SIMS analysis The concentration of metal or alkaline earth metal is 1 × 10⁻⁶ 18 atoms / cm 3 The following is preferable is 2 x 10 16 atoms / cm 3 The following applies: Alkali metals and alkaline earth metals are: When combined with oxide semiconductors, it can generate carriers, increasing the transistor's off-current. This can sometimes result in a large amount of alkali metal in the first oxide semiconductor film 508a. It is preferable to reduce the concentration of alkaline earth metals.

[0138] Furthermore, if nitrogen is present in the first oxide semiconductor film 508a, the electrons, which are carriers, As a result, the carrier density increases, making it more likely to become n-type. Transistors using oxide semiconductor films tend to exhibit normally-on characteristics. Therefore, In the oxide semiconductor film, it is preferable that nitrogen content be reduced as much as possible. For example, The nitrogen concentration obtained by SIMS analysis is 5 × 10⁻⁶ 18 atoms / cm 3 Do the following This is preferable.

[0139] Furthermore, the first oxide semiconductor film 508a and the second oxide semiconductor film 508b are each Non-single-crystal structures are also acceptable. Non-single-crystal structures include, for example, CAAC-OS(C Ax) described later. is Aligned Crystalline Oxide Semiconductor or), including polycrystalline structure, microcrystalline structure, or amorphous structure. In non-single-crystal structures, The crystalline structure has the highest defect level density, while CAAC-OS has the lowest defect level density.

[0140] Here, the band structure of the oxide semiconductor film 508 and the insulating film in contact with the oxide semiconductor film 508 The construction will be explained using Figure 18.

[0141] Figure 18 shows insulating film 507, first oxide semiconductor film 508a, and second oxide semiconductor film 50 This is an example of a band structure in the film thickness direction of a multilayer structure having 8b and an insulating film 514. The band structure is shown for ease of understanding: insulating film 507, first oxide semiconductor film 508a, The energy levels (Ec) at the lower end of the conduction band of the oxide semiconductor film 508b and the insulating film 514 in 2. This indicates.

[0142] Furthermore, in the band structure shown in Figure 18, silicon oxide is used as the insulating film 507 and 514. Using a film, the atomic ratio of metal elements in the first oxide semiconductor film 508a is set to In:Ga:Zn. Using an oxide semiconductor film formed with a metal oxide target of =4:2:4.1, For the oxide semiconductor film 508b, the atomic ratio of the metal elements is In:Ga:Zn = 1:1:1 This is a band diagram of a configuration using a metal oxide film formed with a 0.2 metal oxide target. ru.

[0143] As shown in Figure 18, the first oxide semiconductor film 508a and the second oxide semiconductor film 50 In 8b, the energy levels at the lower end of the conduction band change smoothly. In other words, it is continuous. It can also be said that it changes or is continuously joined. Because it has such a band structure At the interface between the first oxide semiconductor film 508a and the second oxide semiconductor film 508b, Assume that there are no impurities that form defect levels such as trap centers or recombination centers. .

[0144] A continuous junction is formed between the first oxide semiconductor film 508a and the second oxide semiconductor film 508b. To achieve this, a multi-chamber type thin-film deposition apparatus equipped with a load lock chamber (sputtering) is required. The films can be continuously stacked using a (gluing) device without exposing them to the atmosphere.

[0145] By using the configuration shown in Figure 18, the first oxide semiconductor film 508a becomes a well. In a transistor using the above stacked structure, the channel region is a first oxide semiconductor film 5 It can be seen that it is formed in 08a.

[0146] If the second oxide semiconductor film 508b is not formed, the first oxide semiconductor film 508 A trap level can be formed in a. On the other hand, by using the above layered structure, the trap level can be formed. The P level can be formed in the second oxide semiconductor film 508b. Therefore, the first oxide semiconductor The trap level can be separated from the conductive film 508a.

[0147] Furthermore, the first oxide semiconductor film 508a, in which the trap level functions as a channel region, The energy level (Ec) at the bottom of the guide may be further from the vacuum level, and the trap level may be Electrons tend to accumulate. When electrons accumulate in the trap level, negative It becomes a fixed charge, and the transistor's threshold voltage shifts in the positive direction. Therefore, the trap level is the energy level (E) at the lower end of the conduction band of the first oxide semiconductor film 508a. c) It is preferable to have a configuration that is closer to the vacuum level. This makes it less likely for electrons to accumulate in the top level, making it possible to increase the on-current of the transistor. In addition, it can increase the field effect mobility.

[0148] Furthermore, in Figure 18, the second oxide semiconductor film 508b is the first oxide semiconductor film 50 The energy level at the lower end of the conduction band is closer to the vacuum level than in 8a, and typically, the first oxide semiconductor... The energy level at the lower end of the conduction band of the conductive film 508a and the conduction of the second oxide semiconductor film 508b The difference from the energy level at the bottom of the belt is 0.15 eV or greater, or 0.5 eV or greater, and 2e It is less than or equal to V, or less than or equal to 1 eV. That is, the electron affinity of the second oxide semiconductor film 508b The difference between the force and the electron affinity force of the first oxide semiconductor film 508a is 0.15 eV or greater, or The voltage is 0.5 eV or higher and 2 eV or lower, or 1 eV or lower.

[0149] With this configuration, the first oxide semiconductor film 508a becomes the main path for the current. The second oxide semiconductor film 508b functions as a channel region. The first oxide semiconductor film 508a in which the region is formed is composed of one or more metal elements. Since it is an oxide semiconductor film, the first oxide semiconductor film 508a and the second oxide semiconductor film Interfacial scattering is less likely to occur at the interface with 508b. Therefore, carriers Because the movement of A is not hindered, the field-effect mobility of the transistor increases.

[0150] Furthermore, the second oxide semiconductor film 508b prevents it from functioning as part of the channel region. To prevent this, a material with sufficiently low conductivity shall be used. Alternatively, a second oxide semiconductor In film 508b, the electron affinity (the difference between the vacuum level and the energy level at the bottom of the conduction band) is the first It is smaller than oxide semiconductor film 508a, and the energy level at the lower edge of the conduction band is the first oxide semiconductor A material having a difference (band offset) from the lower end energy level of the conduction band of the body membrane 508a is used. It is assumed that there is a difference in threshold voltage that depends on the magnitude of the drain voltage. In order to suppress this, the energy level at the lower end of the conduction band of the second oxide semiconductor film 508b is A vacuum of 0.2 eV or more above the energy level of the lower end of the conduction band of the first oxide semiconductor film 508a It is preferable to use a material that is close to the vacuum level, preferably a material that is close to the vacuum level of 0.5 eV or higher. stomach.

[0151] Furthermore, the second oxide semiconductor film 508b does not contain a spinel-type crystal structure within the film. This is preferable when the second oxide semiconductor film 508b contains a spinel-type crystal structure. At the interface between the spinel-type crystal structure and other regions, the structure of the conductive films 512a and 512b In some cases, the constituent elements may diffuse into the first oxide semiconductor film 508a. If the semiconductor film 508b is CAAC-OS as described later, then the conductive films 512a and 512b The blocking properties of the constituent elements, such as copper, become higher, which is preferable.

[0152] The thickness of the second oxide semiconductor film 508b is determined by the oxidation of the constituent elements of the conductive films 512a and 512b. The film thickness is such that diffusion into the semiconductor film 508b is suppressed, and the insulating film 5 The film thickness is set to be less than the amount that suppresses the supply of oxygen from 14 to the oxide semiconductor film 508b. For example, If the thickness of oxide semiconductor film 508b is 10 nm or more, conductive films 512a and 512b This can suppress the diffusion of the constituent elements into the first oxide semiconductor film 508a. If the thickness of the second oxide semiconductor film 508b is 100 nm or less, then insulating films 514, 51 Oxygen can be effectively supplied from 6 to the first oxide semiconductor film 508a.

[0153] <An insulating film that functions as a protective insulating film for transistors> The insulating films 514 and 516 have the function of supplying oxygen to the oxide semiconductor film 508. The insulating film 518 functions as a protective insulating film for the transistor 500. Films 514 and 516 contain oxygen. In addition, insulating film 514 is permeable to oxygen. This is an insulating film. Note that insulating film 514 is acid when forming insulating film 516 which will be formed later. It also functions as a damage mitigation film for the chromium semiconductor film 508.

[0154] The insulating film 514 has a thickness of 5 nm or more and 150 nm or less, preferably 5 nm or more and 50 nm or less. Silicon oxide, silicon oxide, silicon nitride, etc., with a size of nm or smaller can be used.

[0155] Furthermore, the insulating film 514 preferably has a low defect count, and typically, ESR measurement is used to determine its properties. Furthermore, the spin density of the signal appearing at g=2.001 originates from the dangling bond of silicon. 3 x 10 17 spins / cm 3 The following is preferable. This is because the insulating film 514 If the defect density is high, oxygen will bond to the defects, and oxygen in the insulating film 514 will be lost. This is because the amount of light transmitted decreases.

[0156] Furthermore, in the insulating film 514, all of the oxygen that enters the insulating film 514 from the outside is absorbed by the insulating film 51 Some oxygen does not move to the outside of 4 and remains in the insulating film 514. Also, oxygen in the insulating film 514 As it enters, the oxygen contained in the insulating film 514 moves to the outside of the insulating film 514, thus insulating Oxygen migration may occur in the film 514. The insulating film 514 is permeable to oxygen. When an oxide insulating film is formed, the insulating film 516 provided on the insulating film 514 The desorbed oxygen can be transferred to the oxide semiconductor film 508 via the insulating film 514. .

[0157] Furthermore, the insulating film 514 is formed using an oxide insulating film with a low nitrogen oxide energy density. This can be done. Note that the energy level density of the nitrogen oxide is the upper end of the valence band of the oxide semiconductor film. Energy (E V_OS ) and the energy (E) at the lower end of the conductor of the oxide semiconductor film. C_OS )and It may be formed between these two points. v_os and E c_os The level density of nitrogen oxides is As a low oxide insulating film, a silicon oxidizride film with low nitrogen oxide emission, or nitrogen Aluminum oxide-nitride films with low oxide emission can be used.

[0158] Furthermore, silicon oxidnitride films with low nitrogen oxide emissions are analyzed by the temperature-controlled desorption gas analysis method. In other words, it is a membrane that releases more ammonia than nitrogen oxides, and typically ammonia The amount of molecules released is 1 × 10 18 molecule / cm 3 The above 5 x 10 19 molecule / cm 3 The following applies. The amount of ammonia released is when the surface temperature of the film is between 50°C and 650°C, preferably 50°C. The above refers to the amount released by heat treatment at 550°C or below.

[0159] Nitrogen oxides (NO x (where x is between 0 and 2, preferably between 1 and 2), typically NO 2 or NO forms an energy level in the insulating film 514, etc. This energy level forms in the oxide semiconductor film 50 It is located within the energy gap of 8. Therefore, nitrogen oxides are located within the insulating film 514 and oxidation When diffused to the interface of the semiconductor film 508, the energy level traps electrons on the insulating film 514 side. This can occur. As a result, trapped electrons can be trapped in the insulating film 514 and the oxide semiconductor film. Because it remains near the 508 interface, the transistor's threshold voltage is shifted in the positive direction. Put it away.

[0160] Furthermore, nitrogen oxides react with ammonia and oxygen during heat treatment. Insulating film 514 The nitrogen oxides contained in react with the ammonia contained in the insulating film 516 during the heat treatment. Therefore, nitrogen oxides contained in the insulating film 514 are reduced. At the interface of the oxide semiconductor film 508, electrons are less likely to be trapped.

[0161] As insulating film 514, E v_os and E c_os During the period when the nitrogen oxide level density is low, By using a material insulating film, it is possible to reduce the threshold voltage shift of the transistor. Yes, and it can reduce variations in the electrical characteristics of the transistor.

[0162] Furthermore, the heat treatment in the transistor manufacturing process typically involves temperatures below 400°C or below 375°C. By heat treatment at a temperature of 10°C or higher (preferably 340°C or higher and 360°C or lower), the insulating film 514 is 10 In spectra obtained by measurement at ESR below 0K, the g value is 2.037 or higher and 2.03 A first signal of 9 or less, a second signal with a g value of 2.001 or more and 2.003 or less, and A third signal is observed with a g value between 1.964 and 1.966. Note that the first signal The split width of the first and second signals, and the split width of the second and third signals. The split width is approximately 5 mT in the X-band ESR measurement. The g-value is 2.037. The first signal is 2.039 or less, and the second signal is 2.001 or more and 2.003 or less. The sum of the spin densities of the third signal, which has a g value between 1.964 and 1.966. The total is 1 x 10 18 spins / cm 3 It is less than 1 × 10⁻⁶. 17 spins / cm 3 The above 1 x 10 18 spins / cm 3 It is less than.

[0163] Furthermore, in ESR spectra below 100K, the g value must be between 2.037 and 2.039. The first signal, the second signal with a g value of 2.001 or more and 2.003 or less, and the g value of 1 A third signal between 0.964 and 1.966 indicates nitrogen oxides (NOx). x x is between 0 and 2. The following corresponds to a signal caused by (preferably 1 to 2). Typical examples of nitrogen oxides are These include nitric oxide, nitrogen dioxide, etc. That is, the first g value is between 2.037 and 2.039. A signal, a second signal with a g value of 2.001 or higher and 2.003 or lower, and a g value of 1.9 The smaller the sum of the spin densities of the third signal between 64 and 1.966, the less oxide dielectric strength is. It can be said that the nitrogen oxide content in the rim film is low.

[0164] Also, E v_os and E c_os In between, oxide insulating films with low nitrogen oxide energy levels are S The nitrogen concentration measured by IMS is 6 × 10 20 atoms / cm 3 The following applies:

[0165] The substrate temperature is between 220°C and 350°C, and PEC is performed using silane and nitrous oxide. Using the VD method, E v_os and E c_os Oxide insulation with low nitrogen oxide level density in between By forming a film, it is possible to create a film that is dense and has high hardness.

[0166] The insulating film 516 is an oxide insulating film containing more oxygen than satisfies the stoichiometric composition. It is formed using. An oxide insulating film containing more oxygen than satisfies the stoichiometric composition is Heating causes some of the oxygen to be removed. It contains more oxygen than the oxygen required to satisfy the stoichiometric composition. In the oxide insulating film, TDS analysis showed that the amount of oxygen released, converted to oxygen atoms, was 1.0 × 10⁻¹⁶. 1 9atoms / cm 3 Preferably 3.0 × 10 20 atoms / cm 3 That's all. It is an oxide insulating film. Note that the surface temperature of the film during the above TDS analysis was 100°C or less. A temperature range of 700°C or less, or between 100°C and 500°C, is preferred.

[0167] The insulating film 516 has a thickness of 30 nm to 500 nm, preferably 50 nm or more. Silicon oxide, silicon oxide nitride, etc., with a wavelength of 400 nm or less can be used.

[0168] Furthermore, the insulating film 516 preferably has a low defect count, and typically, ESR measurement is used to determine its defect count. Furthermore, the spin density of the signal appearing at g=2.001 originates from the dangling bond of silicon. is 1.5 × 10 18 spins / cm 3 Less than, and even 1 × 10 18 spins / cm 3 The following is preferable. Note that the insulating film 516 is an oxide semiconductor compared to the insulating film 514. Because it is separated from the body film 508, it can have a higher defect density than the insulating film 514.

[0169] Furthermore, insulating films 514 and 516 can be made of the same type of insulating material, thus providing insulation. In some cases, the interface between film 514 and insulating film 516 cannot be clearly identified. Therefore, in this implementation... In the diagram, the interface between insulating film 514 and insulating film 516 is shown with a dashed line. In the embodiment, a two-layer structure of insulating film 514 and insulating film 516 was described, The invention is not limited to this, and for example, a single-layer structure of insulating film 514 or insulating film 516 may also be used.

[0170] The insulating film 518 blocks oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. It has the ability to do so. By providing the insulating film 518, oxygen from the oxide semiconductor film 508 Diffusion to the outside, diffusion of oxygen contained in insulating films 514 and 516 to the outside, and oxidation from the outside. This prevents hydrogen, water, etc. from entering the semiconductor film 508. For example, a nitride insulating film can be used. The nitride insulating film can be silicon nitride. Examples include silicon nitride, aluminum nitride, and aluminum nitride. In particular, insulating films As for 518, if silicon nitride or silicon nitride film is used, the expansion of oxygen to the outside It is suitable because it can suppress dispersion.

[0171] Furthermore, it has a blocking effect on oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. Instead of a nitride insulating film, an oxide insulating film having a blocking effect of oxygen, hydrogen, water, etc. It may be provided as an insulating film 518. Oxidation having a blocking effect such as oxygen, hydrogen, water Examples of insulating materials include aluminum oxide, aluminum oxide nitride, gallium oxide, and aluminum oxide nitride. Gallium, yttrium oxide, yttrium oxide and nitride, hafnium oxide, hafnium oxide and nitride These include um, etc. Furthermore, as oxide insulating films that have a blocking effect on oxygen, hydrogen, water, etc. It is particularly preferable that the material be aluminum oxide, hafnium oxide, or yttrium oxide. .

[0172] Furthermore, the various films described above, such as conductive films, insulating films, and oxide semiconductor films, are produced by sputtering. It can be formed by the chemo- Atomic Vapor Deposition (ALD) method, or Atomic Vapor Deposition (ALD) method. It may also be formed by the Layer Deposition method. An example of the thermal CVD method is M OCVD(Metal Organic Chemical Vapor Deposit) The tion method is one example.

[0173] Thermal CVD is a film deposition method that does not use plasma, so defects caused by plasma damage can occur. It has the advantage of never being accomplished.

[0174] In the thermal CVD method, the raw material gas and oxidizer are simultaneously introduced into the chamber, and the chamber is subjected to atmospheric pressure. Alternatively, by applying reduced pressure and reacting the film near or on the substrate, the film can be deposited on the substrate. You may go.

[0175] Furthermore, the ALD method maintains atmospheric pressure or reduced pressure inside the chamber, and the raw material gas for the reaction is The gases may be introduced sequentially into the chamber, and the film deposition process may be carried out by repeating this gas introduction sequence. For example, by switching between each switching valve (also called a high-speed valve), you can create two or more types. The raw material gases are supplied to the chamber in order, and the first raw material gas is supplied in order to prevent the mixing of multiple types of raw material gases. An inert gas (such as argon or nitrogen) is introduced simultaneously with or after the refrigerant gas, Introducing the raw material gas (2). Note that if an inert gas is introduced simultaneously, the inert gas should be... It becomes a carrier gas, and when introducing the second raw material gas, an inert gas may also be introduced at the same time. Also, instead of introducing an inert gas, the first raw material gas is discharged by vacuum evacuation. A second raw material gas may be introduced. The first raw material gas is adsorbed onto the surface of the substrate to form the first layer. The film is formed and reacts with a second raw material gas introduced later, so that the second layer is laminated on top of the first layer. A thin film is formed. This process is repeated multiple times while controlling the gas introduction sequence until the desired thickness is reached. By doing so, a thin film with excellent step coverage can be formed. The thickness of the thin film is determined by the order of gas introduction. Because it can be adjusted by the number of times the process is repeated, precise film thickness adjustment is possible. It is suitable for fabricating thin FETs.

[0176] Thermal CVD methods such as MOCVD are used for the conductive film, insulating film, oxide semiconductor film, etc., of the above embodiments. It can form various films, such as metal oxide films, and for example, an In-Ga-ZnO film can be formed. In such cases, trimethylindium, trimethylgallium, and dimethylzinc are used. The chemical formula for trimethylindium is In(CH3)3. The chemical formula for gallium is Ga(CH3)3. The chemical formula for dimethylzinc is Zn( It is CH3)2. Furthermore, it is not limited to these combinations, and trimethylgallium can be substituted. Triethylgallium (chemical formula Ga(C2H5)3) can also be used, and dimethylzinc Alternatively, diethylzinc (chemical formula Zn(C2H5)2) can be used.

[0177] For example, when forming a hafnium oxide film using a film deposition apparatus that utilizes ALD, the solvent and a liquid containing hafnium precursor compounds (hafnium alkoxide, tetrakisdimethyl a A raw material gas obtained by vaporizing midhafnium (TDMAH, etc., a hafnium amide), and oxidation Two types of gases, ozone (O3), are used as agents. The chemical formula for nium is Hf[N(CH3)2]4. Other material liquids include tetra Examples include kiss(ethylmethylamide)hafnium.

[0178] For example, when forming an aluminum oxide film using a film deposition apparatus that utilizes ALD, A liquid containing a medium and an aluminum precursor compound (such as trimethylaluminum (TMA)) Two types of gases are used: a vaporized raw material gas and H2O as an oxidizing agent. The chemical formula for aluminum is Al(CH3)3. Other material solutions include Tris( Dimethylamide) Aluminum, Triisobutylaluminum, Aluminum Tris(2 Examples include 2,6,6-tetramethyl-3,5-heptanedione).

[0179] For example, when forming a silicon oxide film using a film deposition apparatus that utilizes ALD, hexa Chlorodisilane is adsorbed onto the film-forming surface, and chlorine contained in the adsorbed material is removed, resulting in an oxidizing gas (O 2. A radical of nitrous oxide is supplied and reacted with the adsorbed material.

[0180] For example, when depositing a tungsten film using a film deposition apparatus that utilizes ALD, WF6 The initial tungsten film is formed by sequentially introducing gas and B2H6 gas, and then WF A tungsten film is formed by sequentially introducing 6 gas and H2 gas. SiH4 gas may be used instead of S.

[0181] For example, oxide semiconductor films, such as In-Ga-ZnO, can be deposited using an ALD (Advanced Laser Deposition) system. When forming a film, In(CH3)3 gas and O3 gas are introduced sequentially and repeatedly. An O layer is formed, and then Ga(CH3)3 gas and O3 gas are repeatedly introduced in sequence to form GaO A layer is formed, and then Zn(CH3)2 gas and O3 gas are repeatedly introduced sequentially to form ZnO Layers are formed. Note that the order of these layers is not limited to this example. Also, these gases are mixed. This forms mixed compound layers such as In-Ga-O layers, In-Zn-O layers, and Ga-Zn-O layers. It is also acceptable to use H2O obtained by bubbling with an inert gas such as Ar instead of O3 gas. While gas can be used, it is preferable to use O3 gas that does not contain H. Also, In(CH) 3) In(C2H5)3 gas may be used instead of 3 gas. Also, Ga(CH3) Instead of gas 3, Ga(C2H5)3 gas may be used. Also, Zn(CH3)2 gas You may also use "su".

[0182] <Example of semiconductor device configuration 2> Next, regarding a configuration example different from the transistor 500 shown in Figures 14(B) and 14(C), see Figure 16. (A) and (B) will be used for explanation. Note that if the function is the same as the function explained earlier, They share the same hatch pattern and may not be specifically labeled.

[0183] Figure 16(A) is a top view of a transistor 570, which is a semiconductor device according to one aspect of the present invention. Figure 16(B) shows the cross-section between the dashed line X3-X4 shown in Figure 16(A), and Figure This corresponds to the cross-sectional view of the section between Y3 and Y4 shown by the dashed line Y3-Y4 in 16(A).

[0184] Transistor 570 is a conductive film 504 on substrate 502 that functions as a first gate electrode. And, the insulating film 506 on the substrate 502 and the conductive film 504, and the insulating film 507 on the insulating film 506 , an oxide semiconductor film 508 on the insulating film 507, and an insulating film 514 on the oxide semiconductor film 508 , an insulating film 516 on insulating film 514 and a source electrically connected to oxide semiconductor film 508 A conductive film 512a that functions as an electrode and a drain that is electrically connected to the oxide semiconductor film 508. 512b which functions as an in electrode, insulating film 514 on oxide semiconductor film 508, and insulating film Insulating film 516 on 514, insulating film 518 on insulating film 516, and conductive film on insulating film 518 It has 520a and a conductive film 520b on the insulating film 518. insulating films 514, 516, 5 18 functions as the second gate insulating film of transistor 570. Also, the conductive film 520a is conductive through the opening 542c provided in the insulating films 514, 516, and 518. It is electrically connected to film 512b. Also, in transistor 570, conductive film 520a For example, it functions as a pixel electrode used in a display device. Also, transistor 57 At 0, the conductive film 520b is the second gate electrode (also called the back gate electrode) It works.

[0185] Furthermore, as shown in Figure 16(B), the conductive film 520b consists of insulating film 506, insulating film 507, and insulating film. In the openings 542a and 542b provided in the edge film 514, insulating film 516, and insulating film 518 In this configuration, it is connected to the conductive film 504 which functions as the first gate electrode. 20b and the conductive film 504 are given the same potential.

[0186] In this embodiment, openings 542a and 542b are provided, and the conductive film 520b and The configuration for connecting the conductive film 504 has been illustrated, but it is not limited to this. For example, an opening Only one of the openings, either 542a or 542b, is formed, and the conductive film 520b and A configuration that connects the conductive film 504, or without providing openings 542a and 542b, The conductive film 520b and the conductive film 504 may be configured without connection. In the configuration where the conductive film 504 is not connected, the conductive film 520b and the conductive film 504 have different properties. It can provide a potential.

[0187] Furthermore, as shown in Figure 16(B), the oxide semiconductor film 508 functions as a gate electrode. The conductive film 504 and the conductive film 520b, which functions as a second gate electrode, are each facing each other. It is positioned so as to be sandwiched between two conductive films that function as gate electrodes. The second gate The length of the conductive film 520b, which functions as an electrode, in the channel length direction and the length in the channel width direction are The length in the channel length direction and the length in the channel width direction of the oxide semiconductor film 508 are each For a long time, the entire oxide semiconductor film 508 is connected to the conductive film via insulating films 514, 516, and 518. It is covered with 520b. Also, the conductive film 520b and the gate act as a second gate electrode. The conductive film 504 that functions as an electrode consists of insulating film 506, insulating film 507, insulating film 514, The openings 542a and 542b provided in the insulating film 516 and insulating film 518 are connected. Therefore, the side surface of the oxide semiconductor film 508 in the channel width direction is the insulating film 514, insulating film 51 6 and, facing the conductive film 520b which functions as a second gate electrode via the insulating film 518 Yes, they are.

[0188] In other words, in the channel width direction of transistor 570, it functions as a gate electrode. The conductive film 504 and the conductive film 520b, which functions as a second gate electrode, are a gate insulating film and insulating films 506, 507 function as insulating films and insulating film 514 functions as a second gate insulating film. They are connected at the openings provided in 516 and 518 and function as gate insulating films. insulating films 506, 507 and insulating films 514, 516 that function as second gate insulating films. The structure is such that the oxide semiconductor film 508 is surrounded via 518.

[0189] Having this configuration, the oxide semiconductor film 508 contained in transistor 570 conductive film 504 functioning as a gate electrode and conductive film functioning as a second gate electrode It can be electrically enclosed by an electric field of 520b. Like transistor 570, A channel region is formed in an oxide semiconductor film by the electric fields of the first electrode and the second gate electrode. The device structure of a transistor that electrically surrounds a channel is called a surrounded channel. This can be called an s-channel structure.

[0190] Transistor 570 has an s-channel structure and therefore functions as a gate electrode. The conductive film 504 effectively induces an electric field in the oxide semiconductor film 5 Because it can be applied to 08, the current driving capability of transistor 570 is improved, resulting in high O It becomes possible to obtain on-current characteristics. Also, it is possible to increase the on-current, It becomes possible to miniaturize transistor 570. Also, transistor 570 is a game Conductive film 504 functions as a gate electrode and conductive film 520b functions as a second gate electrode. Because it has a structure surrounded by it, the mechanical strength of transistor 570 can be increased. Cut.

[0191] Regarding the other components of transistor 570, see the same as those of transistor 500 shown above. They are similar and produce the same effect.

[0192] Furthermore, the transistor according to this embodiment can be freely combined with each of the above structures. It is possible to use the transistor 500 shown in Figure 14(A)(B) as a display device. The transistor used in the pixels is the transistor 570 shown in Figure 16(A)(B) of the display device. It can be used as a gate driver transistor.

[0193] <Method for fabricating semiconductor devices 1> Next, a method for fabricating a transistor 500, which is a semiconductor device according to one aspect of the present invention, is shown in Figure This will be explained in detail using Figures 10(A), (B), (C) through 14(A). Note that Figure 10(A) Figures (B), (C) through 14(A) are cross-sectional views illustrating a method for manufacturing a semiconductor device.

[0194] First, a conductive film is formed on the substrate 502, and the conductive film is subjected to a lithography process and an etching process. The conductive film 504, which functions as a gate electrode, is formed by processing the material. Insulating films 506 and 507, which function as gate insulating films, are formed on 04 (see Figure 10(A)). see).

[0195] In this embodiment, a glass substrate is used as the substrate 502, and a conductive electrode functions as the gate electrode. A tungsten film with a thickness of 100 nm is formed as the electrical film 504 by sputtering. Furthermore, a silicon nitride film with a thickness of 400 nm was formed as insulating film 506 by the PECVD method. A silicon oxidizride film with a thickness of 50 nm is formed as insulating film 507 by the PECVD method. .

[0196] Furthermore, the insulating film 506 can be a laminated structure of silicon nitride films. The insulating film 506 is a first silicon nitride film, a second silicon nitride film, and a third silicon nitride film. A three-layer laminated structure with a silicon film can be formed. An example of this three-layer laminated structure is as follows: It can be formed in this way.

[0197] For example, the first silicon nitride film is silane at a flow rate of 200 sccm, and silane at a flow rate of 2000 sccm. PECVD using sccm of nitrogen and ammonia gas at a flow rate of 100 sccm as raw material gases. It supplies power to the reaction chamber of the apparatus, controls the pressure inside the reaction chamber to 100 Pa, and uses a high frequency of 27.12 MHz. By supplying 2000W of power using a wave power supply, you can form it to a thickness of 50nm. stomach.

[0198] The second silicon nitride film was a silane at a flow rate of 200 sccm, and a flow rate of 2000 sccm Nitrogen and ammonia gas at a flow rate of 2000 sccm are used as raw material gases in a PECVD apparatus. A 27.12 MHz high-frequency power supply is supplied to the reaction chamber, controlling the pressure inside the chamber to 100 Pa. By supplying 2000W of power using this method, the material can be formed to a thickness of 300nm.

[0199] The third silicon nitride film is a silane at a flow rate of 200 sccm, and a silane at a flow rate of 5000 sccm. A nitrogen atom at a concentration of 1 cm is supplied as a raw material gas to the reaction chamber of the PECVD apparatus, and the pressure inside the reaction chamber is set to 100. It is controlled to Pa and supplied with 2000W of power using a 27.12MHz high-frequency power supply, It should be formed so that the depth is 50 nm.

[0200] Furthermore, the first silicon nitride film, the second silicon nitride film, and the third silicon nitride film The substrate temperature during formation can be kept below 350°C.

[0201] By making the insulating film 506 a three-layer laminated structure of silicon nitride films, for example, conductive film 50 When a conductive film containing copper (Cu) is used in step 4, the following effects are achieved.

[0202] The first silicon nitride film suppresses the diffusion of copper (Cu) elements from the conductive film 504. Yes, it is possible. The second silicon nitride film has the function of releasing hydrogen and functions as a gate insulating film. The dielectric strength of the insulating film can be improved. The third silicon nitride film is the third silicon nitride Low hydrogen release from the first film, and diffusion of hydrogen released from the second silicon nitride film. It can be suppressed.

[0203] The insulating film 507 is an oxide semiconductor film 508 that is formed later (more specifically, the first To improve the interfacial properties with the oxide semiconductor film 508a), an insulating film containing oxygen is formed. It would be preferable if it were.

[0204] Next, an oxide semiconductor film 509 is deposited on the insulating film 507 at the first temperature. As the material semiconductor film 509, a first oxide semiconductor film 509a is formed, followed by a second A 509b oxide semiconductor film is deposited (see Figure 10(B)).

[0205] The first temperature for depositing the oxide semiconductor film 509 is preferably above room temperature and below 340°C. The temperature should be above room temperature and below 300°C, more preferably between 100°C and 250°C, and even more preferably between 300°C and 250°C. The temperature is between 100°C and 200°C. By heating the oxide semiconductor film 509 to form the film, The crystallinity of the oxide semiconductor film 509 can be improved. On the other hand, as the substrate 502, When using a glass substrate (e.g., 6th to 10th generation), the first temperature is 150°C. If the temperature is below 340°C, the substrate 502 may warp. Therefore, large glass substrates When using this, the first temperature is set to 100°C or higher and less than 150°C, This can suppress distortion of the circuit board.

[0206] Furthermore, the base during the deposition of the first oxide semiconductor film 509a and the second oxide semiconductor film 509b The plate temperatures may be the same or different. However, the first oxide semiconductor film 509a and the second By keeping the substrate temperature the same as that of the oxide semiconductor film 509b (part 2), manufacturing costs are reduced. It is preferable because it allows for this.

[0207] In this embodiment, an In-Ga-Zn metal oxide target (In:Ga:Zn=4: Using a 2:4.1 [atomic ratio], the first oxide semiconductor film 50 is produced by sputtering. 9a is deposited, and then in a vacuum, the In-Ga-Zn metal oxide target (In Using Ga:Zn=1:1:1.2 (atomic ratio), the second is produced by sputtering. An oxide semiconductor film 509b is formed. Also, the first oxide semiconductor film 509a and the second acid The substrate temperature during the deposition of the ionized semiconductor film 509b is set to 170°C.

[0208] Furthermore, when depositing oxide semiconductor film 509 by sputtering, the sputtering gas This involves using noble gases (typically argon), oxygen, or a mixture of noble gases and oxygen as appropriate. In the case of mixed gases, it is preferable to increase the gas ratio of oxygen to the noble gas. Also, spa It is also necessary to increase the purity of the sputtering gas. For example, oxygen used as a sputtering gas. The gas or argon gas has a dew point of -40°C or lower, preferably -80°C or lower, more preferably By using gas purified to below -100℃, more preferably below -120℃, This makes it possible to prevent moisture and other substances from being incorporated into the oxide semiconductor film 509 as much as possible.

[0209] Furthermore, when depositing an oxide semiconductor film 509 by sputtering, the sputtering apparatus The chamber in this chamber removes as much water and other impurities as possible from the oxide semiconductor film 509. To achieve a high vacuum (5 × 10) using an adsorption-type vacuum pump such as a cryopump, -7 Pa or more 1×10 -4 It is preferable to exhaust the gas to a level of approximately Pa or less. Alternatively, turbo molecules By combining a pump and a cold trap, gases, especially carbon, are drawn from the exhaust system into the chamber. It is preferable to ensure that the hydrogen-containing gas does not flow back.

[0210] Subsequently, the oxide semiconductor film 509 is processed to form island-shaped oxide semiconductor films 508. Furthermore, the first oxide semiconductor film 509a is formed in the island-like first oxide semiconductor film 508a, and the second The oxide semiconductor film 509b becomes an island-like second oxide semiconductor film 508b (Figure 10(C)). reference).

[0211] Subsequently, without performing a step at a temperature higher than the first temperature described above, the insulating film 50 7 and a conductive film 512 which will serve as the source electrode and drain electrode are placed on the oxide semiconductor film 508. It is formed by the puttering method (see Figure 11(A)).

[0212] In this embodiment, the conductive film 512 is a tungsten film with a thickness of 50 nm and a film with a thickness of 40 A multilayer film consisting of a 0 nm aluminum film and a 0 nm aluminum film stacked sequentially is formed by sputtering. In this embodiment, a two-layer laminated structure of conductive film 512 is used, but the embodiment is not limited to this. It is not possible. For example, as conductive film 512, a tungsten film with a thickness of 50 nm and a film with a thickness of 400 nm A three-layer laminated structure consisting of a 100nm thick aluminum film and a 100nm thick titanium film stacked in sequence. You may do so.

[0213] Subsequently, masks 536a and 536b are formed on the desired region on the conductive film 512 (Figure 11(B)).

[0214] In this embodiment, a photosensitive resin film is applied on the conductive film 512, and the photosensitive resin Masks 536a and 536b are formed by patterning the film using a lithography process. ru.

[0215] Subsequently, the conductive film 512 and the masks 536a and 536b are etched with etchant 538. By processing the conductive film 512 using this method, the conductive films 512a, which are separated from each other, Forms 512b (see Figure 11(C)).

[0216] In this embodiment, a dry etching apparatus is used to process the conductive film 512. However, the method for forming the conductive film 512 is not limited to this, for example, Etchan By using the chemical solution on 538, the conductive film 512 and The second oxide semiconductor film 508b may be processed using a wet etching apparatus. Therefore, rather than processing the conductive film 512, the conductive film 512 is processed using a dry etching apparatus. This allows for the formation of finer patterns. On the other hand, dry etching equipment Rather than processing the conductive film 512 using a wet etching apparatus, it is better to process the conductive film 51 Processing option 2 can reduce manufacturing costs.

[0217] Subsequently, a second oxide semiconductor film 508b, conductive films 512a and 512b, and a mask are applied. From 536a and 536b, the second oxide semiconductor film 508 is formed using the etchant 539. Clean the surface of b (see Figure 12(A)).

[0218] The cleaning method described above includes, for example, cleaning using a chemical solution such as phosphoric acid. By cleaning with chemicals such as these, impurities attached to the surface of the second oxide semiconductor film 508b can be removed. Pure substances (for example, elements contained in conductive films 512a and 512b) can be removed. However, this cleaning is not always necessary, and in some cases, it may not be required.

[0219] Furthermore, during the formation of the conductive films 512a and 512b, and / or during the cleaning process described above, the second The region exposed from the conductive films 512a and 512b of the oxide semiconductor film 508b is the first oxide It may be thinner than the material semiconductor film 508a.

[0220] Furthermore, during the formation of the conductive films 512a and 512b, and / or during the cleaning process described above, the second The region exposed from the conductive films 512a and 512b of the oxide semiconductor film 508b does not become thinner. There are also cases where this is the case. An example of this case is shown in Figures 15(A) and 15(B). Figures 15(A) and 15(B) show semiconductors. This is a cross-sectional view showing an example of a device. Figure 15(A) shows the transistor 5 shown in Figure 14(B). This is an example of a case where the second oxide semiconductor film 508b of 00 does not become thinner. Also, Figure 15( As shown in B), the thickness of the second oxide semiconductor film 508b is predetermined to be the same as the thickness of the first oxide semiconductor film It is formed to be thinner than 508a, and the film thickness in the region exposed from the conductive films 512a and 512b is shown in Figure 1. The film thickness may be the same as that of transistor 500 shown in 4(B). Also, as shown in Figure 15(C) To that end, the thickness of the second oxide semiconductor film 508b is predetermined to match the thickness of the first oxide semiconductor film 508a. It is formed to be thinner than the second oxide semiconductor film 508b and insulating film 507. 19 may be formed. In this case, the insulating film 519 has a second oxide semiconductor film 508b and a conductive film. An opening is formed for the insulating film 512a and the conductive film 512b to come into contact. The insulating film 519 is an insulating film. It can be formed using the same materials and formation method as the border film 514.

[0221] Next, by removing masks 536a and 536b, the second oxide semiconductor film 508b is exposed. A conductive film 512a that functions as a source electrode and a drain on a second oxide semiconductor film 508 A conductive film 512b that functions as an electrode is formed. Also, the oxide semiconductor film 508 is This results in a stacked structure consisting of a first oxide semiconductor film 508a and a second oxide semiconductor film 508b. (See Figure 12(B)).

[0222] Subsequently, the oxide semiconductor film 508 and the conductive films 512a and 512b are subjected to a first protective insulating film. An insulating film 514 that functions as a border film, and an insulating film 516 that functions as a second protective insulating film, After forming the first barrier film 531, the first barrier film 531 is formed (see Figure 12(C)).

[0223] Furthermore, after forming the insulating film 514, the insulating film 516 is formed continuously without exposure to the atmosphere. It is preferable to do so. After forming the insulating film 514, do not open it to the atmosphere, and control the flow rate, pressure, and high of the raw material gas. By adjusting the frequency power and substrate temperature to one or more units, the insulating film 516 is formed continuously, The concentration of impurities originating from atmospheric components can be reduced at the interface between the edge film 514 and the insulating film 516. At the same time, the oxygen contained in the insulating films 514 and 516 is transferred to the oxide semiconductor film 508. This makes it possible to reduce the amount of oxygen vacancies in the oxide semiconductor film 508.

[0224] For example, as insulating film 514, a silicon oxidizride film is formed using the PECVD method. This is possible. In this case, the raw material gases include a silicon-containing sedimentary gas and an oxidizing gas. It is preferable to use [a specific type of gas]. Typical examples of silicon-containing sedimentary gases include silane and disila. Examples include nitrates, trisilanes, and silane fluorides. Oxidizing gases include nitrous oxide and nitrogen dioxide. There are elements such as [unclear]. Also, the flow rate of the oxidizing gas is greater than 20 times the flow rate of the sedimentary gas mentioned above. The pressure should be less than 100 times, preferably between 40 and 80 times, and the pressure inside the processing chamber should be less than 100 Pa. By using a PECVD method with a pressure of full, preferably 50 Pa or less, the insulating film 514 is treated with nitrogen This results in an insulating film that contains and has a low defect rate.

[0225] In this embodiment, the insulating film 514 is set to a temperature of 220°C for holding the substrate 502. The raw materials are silane at a flow rate of 50 sccm and nitrous oxide at a flow rate of 2000 sccm. The pressure inside the processing chamber is set to 20 Pa, and the high-frequency power supplied to the parallel plate electrodes is 13.56 MHz. Hz, 100W (power density is 1.6 × 10⁻⁶) -2 W / cm 2 The PECVD method is used as follows: A silicon oxide nitride film is formed using this method.

[0226] As the insulating film 516, the substrate placed in the vacuum-evacuated processing chamber of the PECVD apparatus Maintain the temperature between 180°C and 350°C, introduce the raw material gas into the processing chamber, and adjust the pressure within the processing chamber. The pressure is set to 100 Pa or more and 250 Pa or less, more preferably 100 Pa or more and 200 Pa or less. , 0.17 W / cm² is applied to the electrode installed in the processing chamber. 2 More than 0.5W / cm 2 Below, further good The current level is 0.25 W / cm². 2 More than 0.35W / cm 2 The following conditions apply to supplying high-frequency power: This then forms a silicon oxide film or a silicon oxide-nitride film.

[0227] As the film deposition conditions for insulating film 516, a high-frequency current with the above power density is used in a reaction chamber at the above pressure. By supplying power, the decomposition efficiency of the raw material gas in the plasma increases, and the amount of oxygen radicals increases. As the oxidation of the raw material gas progresses, the oxygen content in the insulating film 516 becomes greater than the stoichiometric composition. also increases. On the other hand, in the film formed at the above temperature, the bonding force between silicon and oxygen is weak. Therefore, a part of the oxygen in the film desorbs due to the heat treatment in the subsequent process. As a result, an oxide containing more oxygen than oxygen satisfying the stoichiometric composition and from which a part of the oxygen desorbs by heating insulating film can be formed.

[0228] Note that in the step of forming the insulating film 516, the insulating film 514 serves as a protective film for the oxide semiconductor film 508. Therefore, the insulating film 516 can be formed using high-frequency power with a high power density while reducing damage to the oxide semiconductor film 508.

[0229] [[ID=MS18]]Note that in the film formation conditions of the insulating film 516, by increasing the flow rate of the depositable gas containing silicon with respect to the oxidizing gas, it is possible to reduce the defect amount of the insulating film 516. Typically, by ESR measurement, the spin density of the signal appearing at g = 2.001 derived from the dangling bond of silicon is less than 6 × 10 spins / cm 17 17 spins / cm [[ID=2,3]] 3 3 preferably less than 3 × 10 17 spins / cm 3 preferably 1.5 × 10 17 spins / cm 3 or less, preferably 1.5 × 10 spins / cm 3 or less, an oxide insulating film with a small defect amount can be formed. As a result, the reliability of the transistor can be improved. can be improved.

[0230] In addition, after forming the insulating films 514 and 516 (in other words, after forming the insulating film 516 and before forming the first barrier film 531), heat treatment may be performed. By this heat treatment, the nitrogen oxides contained in the insulating films 5 14 and 516 can be reduced. Also, by the above heat treatment This transfers some of the oxygen contained in the insulating films 514 and 516 to the oxide semiconductor film 508, causing oxidation. The amount of oxygen vacancies in the semiconductor film 508 can be reduced.

[0231] The heat treatment temperature for insulating films 514 and 516 is typically up to 400°C, preferably. Less than 375°C, more preferably 340°C or more and less than 360°C, even more preferably 15 The temperature should be between 0°C and 350°C. Heat treatment should be performed using nitrogen, oxygen, and ultra-dry air (with a water content of 20%). (Air) with a concentration of ppm or less, preferably 1 ppm or less, preferably 10 ppb or less, or dilute gas This should be done under an atmosphere of oxygen (argon, helium, etc.). It is preferable that the gas or noble gas does not contain hydrogen, water, etc. The heat treatment is performed using an electric furnace. RTA devices and the like can be used.

[0232] The first barrier film 531 contains oxygen and metals (indium, zinc, titanium, aluminum, Selected from tungsten, tantalum, molybdenum, hafnium, or yttrium. The first barrier film 531 is made of indium stannic acid. Indium tin silicon (also known as ITO: Indium Tin Oxide) If it is an oxide (hereinafter also called ITSO) or indium oxide, the coverage of the uneven surface is It is favorable because it is good.

[0233] Furthermore, the first barrier film 531 can be formed using a sputtering method. When the first barrier film 531 is thin, it suppresses oxygen that could be released to the outside from the insulating film 516. This can sometimes become difficult. On the other hand, if the first barrier film 531 is thick, the insulating film 51 6. In some cases, oxygen cannot be suitably added to the first barrier film 531. Preferably, the wavelength is 1 nm to 20 nm, more preferably 2 nm to 10 nm. In this embodiment, a 5 nm thick ITSO film is deposited as the first barrier film 531. do.

[0234] Subsequently, oxygen 540 is introduced through the first barrier film 531 as a second protective insulating film. It is added to the insulating film 516. Note that in the figure, the acid added to the insulating film 516 The element is schematically represented as oxygen 540a (see Figure 13(A)). Also, oxygen 540 is an oxygen atom. It may also be added to the border film 514.

[0235] A method for adding oxygen 540 to the insulating film 516 via the first barrier film 531 is: Methods include on-doping, ion implantation, and plasma treatment. Also, as for oxygen 540... Examples include excess oxygen or oxygen radicals. Also, when adding oxygen 540, the substrate By applying a bias to the side, oxygen 540 can be effectively added to the insulating film 516. For example, the above bias could be a power density of 1 W / cm². 2 More than 5W / cm 2 The following This is sufficient. By providing a first barrier film 531 on the insulating film 516 and adding oxygen, the first The barrier film 531 functions as a protective film that suppresses the detachment of oxygen from the insulating film 516. Therefore, more oxygen can be added to the insulating film 516.

[0236] Next, the first barrier film 531 or a portion of the first barrier film 531, and the second protective insulation A portion of the insulating film 516, which functions as a film, is removed by the etchant 542 (Figure 13). (See (B)).

[0237] Removal of a portion of the first barrier film 531 and the insulating film 516 which functions as a second protective insulating film. The removal methods include dry etching, wet etching, or dry etching. Methods that combine the method with wet etching include dry etching. In the case of the law, etchant 542 is an etching gas, and in the wet etching method... In this case, Etchant 542 is a chemical solution. In this embodiment, Wet Etchant 542 The first barrier film 531 is removed using the ching method. Method for removing the first barrier film 531 Therefore, using the wet etching method is preferable because it can reduce manufacturing costs.

[0238] Subsequently, an insulating film 518, which functions as a second barrier film, is deposited on the insulating film 516. (See Figure 14(A)).

[0239] When the insulating film 518 is deposited by the PECVD method, the substrate temperature is preferably up to 400°C. The temperature is less than 75°C, more preferably 340°C to 360°C. The insulating film 518 is then deposited. By setting the substrate temperature within the above range, the excess oxygen or oxygen radicals mentioned above can be reduced. It can be diffused into the oxide semiconductor film 508. Also, when forming the insulating film 518 It is preferable to keep the substrate temperature within the above-mentioned range because this allows for the formation of a dense film.

[0240] For example, when forming a silicon nitride film as insulating film 518 by the PECVD method, It is preferable to use depositing gases containing condensate, nitrogen, and ammonia as raw material gases. By using a small amount of ammonia compared to nitrogen, the ammonia dissociates in the plasma and activates Active species are generated. The active species break the bonds between silicon and hydrogen contained in the depositable gas containing silicon, and the triple bond of nitrogen. As a result, the bonds between silicon and nitrogen are promoted, the bonds between silicon and hydrogen are few, the defects are few, and a dense silicon nitride film can be formed. On the other hand, when the amount of ammonia relative to nitrogen is large, the decomposition of the depositable gas containing silicon and nitrogen does not proceed, the silicon and hydrogen bonds remain, the defects increase, and a rough silicon nitride film is formed. For these reasons, in the source gas, it is preferable that the flow rate ratio of nitrogen to ammonia is 5 times or more and 50 times or less, and 10 times or more and 50 times or less. In this embodiment, as the insulating film 518, a 50 nm thick silicon nitride film is formed using a PECVD apparatus with silane, nitrogen, and ammonia as source gases. The flow rates are 50 sccm for silane, 5000 sccm for nitrogen, and 100 sccm for ammonia. The pressure in the processing chamber is 100 Pa, the substrate temperature is 350 °C, and 1000 W of high-frequency power is supplied to the parallel plate electrode using a 27.12 MHz high-frequency power supply. The PECVD .

[0241] apparatus is a parallel plate type PECVD apparatus with an electrode area of 6000 cm . When the supplied power is converted to the power per unit area (power density), it is 1.7×10 W / cm . Also, heat treatment may be performed after the formation of the insulating film 518 that functions as the second barrier film. By the heat treatment after the formation of the insulating film 518, the excess oxygen or oxygen radicals contained in the insulating film 516 are diffused into the oxide semiconductor film 508, and the oxygen vacancies in the oxide semiconductor film 508 2 are filled. are filled. -1 W / cm 2 . .

[0242] Furthermore, heat treatment may be performed after the formation of the insulating film 518 that functions as the second barrier film. By the heat treatment after the formation of the insulating film 518, the excess oxygen or oxygen radicals contained in the insulating film 516 are diffused into the oxide semiconductor film 508, and the oxygen vacancies in the oxide semiconductor film 508 are filled. Losses can be compensated for. Alternatively, by heat deposition of the insulating film 518, the insulating film 5 Excess oxygen or oxygen radicals contained in 16 are diffused into the oxide semiconductor film 508, and acid It can fill oxygen vacancies in the ionized semiconductor film 508.

[0243] By following the above steps, the transistor 500 shown in Figure 14(B) can be formed.

[0244] <Method for fabricating semiconductor devices, part 2> Next, the method for manufacturing transistor 500 shown in Figures 10(A), (B), (C) to 14(A) The law and different manufacturing methods are explained below.

[0245] First, similar to <Method 1 for Manufacturing Semiconductor Devices>, see Figures 10(A)(B)(C) and 11(A )(B)(C), and the process shown in Figure 12(A)(B)(C) is carried out. After that, Figure 13( The steps shown in A)(B) and Figure 14(A) are not performed. That is, the structure shown in Figure 12(C) In this configuration, it has the same function as transistor 500 shown in Figures 14(B) and 14(C).

[0246] In this case, a metal oxide film is used as the first barrier film 531, and the metal oxide film is It is preferable to deposit a film of aluminum oxide, hafnium oxide, or yttrium oxide.

[0247] Furthermore, the first barrier film 531 may be aluminum oxide, hafnium oxide, or oxide When depositing yttrium using the sputtering method, the sputtering gas is small It is preferable that both contain oxygen. When forming the first barrier film 531, sputtering gas By using oxygen, the oxygen becomes an oxygen radical in the plasma, and the oxygen or Either or both of these oxygen radicals may be added to the insulating film 516. Therefore, the step of adding oxygen 540 shown in Figure 13(A) does not need to be performed. In other words, During the formation of the first barrier film 531, an oxygen addition treatment is performed, and the formation of the first barrier film 531 This makes it possible to perform the film formation simultaneously. The first barrier film 531 is formed from the first barrier film During film formation (especially in the initial stages), it has the function of adding oxygen, but the first barrier film 53 After the formation of 1, it has the function of blocking oxygen.

[0248] Furthermore, as the first barrier film 531, for example, aluminum oxide can be used by sputtering. When forming the film, a mixed layer is formed near the interface between the insulating film 516 and the first barrier film 531. In some cases, the insulating film 516 is a silicon oxidizide film, and the mixed layer is Al x Si y O z It can be formed.

[0249] Furthermore, the first barrier film 531 may be aluminum oxide, hafnium oxide, or oxide When using yttrium, aluminum oxide, hafnium oxide, and yttrium oxide are used. It has high insulating properties and high oxygen barrier properties. Therefore, as shown in Figure 13(B), A step to remove the barrier film 531, and a step to form the insulating film 518 shown in Figure 14(A). It is not necessary to perform the procedure. Therefore, the first barrier film 531 has the same function as the insulating film 518. To possess.

[0250] Furthermore, the substrate temperature during the deposition of the first barrier film 531 should be up to 400°C, preferably 375°C. By heating and forming the film at a temperature less than, more preferably between 340°C and 360°C, the insulating film 516 The process involves diffusing the added excess oxygen or oxygen radicals into the oxide semiconductor film 508. Alternatively, after forming the first barrier film 531, it can be heated to 400°C, preferably 3°C. When heat treatment is performed at a temperature below 75°C, more preferably between 340°C and 360°C, the insulating film 51 The excess oxygen or oxygen radicals added to 6 are diffused into the oxide semiconductor film 508. It is possible.

[0251] Thus, as the first barrier film 531, aluminum oxide, hafnium oxide, and By using yttrium oxide, it becomes possible to shorten the manufacturing process for semiconductor devices. This allows for reduced manufacturing costs.

[0252] <Method for fabricating semiconductor devices, part 3> Next, a method for manufacturing a transistor 570, which is one embodiment of the present invention, is shown in Figure 17(A)( Figures B) and C will be used to explain in detail. Note that Figures 17(A), (B), and (C) show the semiconductor device. This is a cross-sectional view illustrating the manufacturing method.

[0253] First, the same process as the method for manufacturing transistor 500 shown above (Figures 10(A) to 14) (A) Perform the steps shown in (A).

[0254] Next, a mask is formed on the insulating film 518 by a lithography process, and insulating films 514, 51 6. An opening 542c is formed in a desired region of 518. Also, a lithographic film is applied to the insulating film 518. A mask is formed by a process, and the insulating films 506, 507, 514, 516, and 518 are desired. Openings 542a and 542b are formed in the region. Note that opening 542c is connected to the conductive film 512 It is formed to reach b. Also, the openings 542a and 542b are each connected to the conductive film 50 It is formed to reach 4 (see Figure 17(A)).

[0255] Furthermore, openings 542a, 542b and opening 542c may be formed in the same process, or differently. The openings 542a, 542b and 542c may be formed in the same process. If this is done, for example, it can be formed using a gray tone mask or a halftone mask. This can be done. Alternatively, the openings 542a and 542b may be formed in multiple steps. For example... First, insulating films 506 and 507 are processed, and then insulating films 514, 516, and 518 are processed.

[0256] Next, a conductive film 52 is applied to the insulating film 518 so as to cover the openings 542a, 542b, and 542c. It forms 0 (see Figure 17(B)).

[0257] Examples of conductive films 520 include indium (In), zinc (Zn), and tin (Sn). A material containing one selected from can be used. In particular, as the conductive film 520, Indium oxide containing tungsten, indium zinc oxide containing tungsten oxide, Titanium oxide containing indium oxide, titanium oxide containing indium tin oxide, indium Indium tin oxide (ITO), indium zinc oxide, indium tin silicon oxide (IT A conductive material with light-transmitting properties such as SO(SO) can be used. Also, the conductive film 520 is For example, it can be formed using the sputtering method. This involves forming an ITSO film with a thickness of 110 nm using the sputtering method.

[0258] Next, a mask is formed on the conductive film 520 by a lithography process, and the conductive film 520 is desired By processing it into this shape, conductive films 520a and 520b are formed (see Figure 17(C)).

[0259] Regarding the formation method of conductive films 520a and 520b, dry etching and wet etching methods are used. Examples include the etching method, or a method combining dry etching and wet etching. In this embodiment, the conductive film 520 is prepared using a wet etching method. The film is processed into 520a and 520b.

[0260] By following the above steps, the transistor 570 shown in Figures 16(A) and 16(B) can be manufactured.

[0261] The configurations and methods shown in this embodiment can be appropriately combined with the configurations and methods shown in other embodiments. They can be used together. (Embodiment 3) In this embodiment, the structure of the oxide semiconductor included in a semiconductor device according to one aspect of the present invention is described below. Then, I will explain in detail.

[0262] <Oxide semiconductor structure> Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single-crystal oxide semiconductor, CAAC-OS (C Axis Aligned) is used. Crystalline Oxide Semiconductor, Polycrystalline Oxide Semiconductors, nc-OS (nanocrystalline oxide semiconductor) uctor), pseudo-amorphous oxide semiconductor (a-like OS: amorphous l Examples include amorphous oxide semiconductors (ike Oxide Semiconductor).

[0263] From another perspective, oxide semiconductors include amorphous oxide semiconductors and other crystalline oxides. They can be divided into semiconductors and crystalline oxide semiconductors. Crystalline oxide semiconductors include single-crystal oxide semiconductors and CAAC- Examples include OS, polycrystalline oxide semiconductors, and nc-OS.

[0264] Generally, an amorphous structure is defined as a structure that is not fixed in a metastable state and is isotropic. It is known that it does not have a heterogeneous structure. Also, the bond angles are flexible and short distance It can also be described as a structure that possesses deorderliness but lacks long-range orderliness.

[0265] Conversely, in the case of oxide semiconductors, which are inherently stable, they are perfectly amorphous (complete It cannot be called an oxide semiconductor (which is amorphous). Also, it is not isotropic. (For example, an oxide semiconductor having a periodic structure in a minute region) is subjected to complete amorphous oxidation. It cannot be called a physical semiconductor. However, a-like OS is a peripheral semiconductor in a minute region. Although it has a structural form, it also has voids (also called porous structures) and is therefore an unstable structure. In terms of physical properties, it can be said to be similar to an amorphous oxide semiconductor.

[0266] <caac-os> First, let me explain CAAC-OS.

[0267] CAAC-OS is an oxide having multiple c-axis oriented crystalline portions (also called pellets). It is a type of semiconductor.

[0268] Transmission Electron Microscope (TEM) A composite analysis image of the bright-field image and diffraction pattern of CAAC-OS (high-angle scope) is obtained. Also called a high-resolution TEM image, when observed, multiple pellets can be identified. On the other hand, in high-resolution TEM images, the boundaries between pellets, i.e., grain boundaries, and It is also said that it is not possible to clearly confirm the grain boundaries. Therefore, CAAC-OS is said to be at the grain boundaries. This means that a decrease in electron mobility caused by this phenomenon is less likely to occur.

[0269] The following describes CAAC-OS observed by TEM. Figure 19(A) The image shows a high-resolution TEM image of the cross-section of CAAC-OS observed from a direction approximately parallel to the sample surface. For observing high-resolution TEM images, spherical aberration correction is necessary. The n Corrector function was used. High-resolution TEM images using spherical aberration correction function were obtained. This is specifically called a Cs-corrected high-resolution TEM image. Acquisition of a Cs-corrected high-resolution TEM image can be done, for example, This is performed using an atomic-resolution analytical electron microscope such as the JEM-ARM200F manufactured by JEOL Ltd. It is possible.

[0270] Figure 19(B) shows an enlarged Cs-corrected high-resolution TEM image of region (1) in Figure 19(A). Figure 19(B) shows that the metal atoms in the pellet are arranged in layers. The arrangement of metal atoms in each layer is the plane (also called the surface to be formed) that forms the CAAC-OS film. Alternatively, it reflects the irregularities of the upper surface and is parallel to the surface or upper surface of the CAAC-OS that is formed on it.

[0271] As shown in Figure 19(B), CAAC-OS has a characteristic atomic arrangement. Figure 19(C Figures 19(B) and 19(C) show characteristic atomic arrangements indicated by auxiliary lines. ) Therefore, the size of a single pellet can be 1 nm or larger, or 3 nm or larger, It can be seen that the size of the gap created by the tilt between the toe and the pellet is approximately 0.8 nm. Therefore, pellets can also be called nanocrystals (nc). Furthermore, CAAC-OS is used in CANC (C-Axis Aligned nanocr It can also be called an oxide semiconductor containing ystals.

[0272] Here, based on the Cs-corrected high-resolution TEM image, the pellets of CAAC-OS on substrate 5120 are... The arrangement of the 5100 can be schematically represented as a structure resembling stacked bricks or blocks. This is the result (see Figure 19(D)). Between the pellets observed in Figure 19(C) The area where the inclination occurs corresponds to region 5161 shown in Figure 19(D).

[0273] Furthermore, Figure 20(A) shows the plane of CAAC-OS observed from a direction approximately perpendicular to the sample surface. The s-corrected high-resolution TEM images are shown. Regions (1), (2), and (3) of Figure 20(A) are shown. ) are enlarged Cs-corrected high-resolution TEM images, shown in Figure 20(B), Figure 20(C), and This is shown in Figure 20(D). From Figures 20(B), 20(C), and 20(D), the pellets are It can be confirmed that the metal atoms are arranged in a triangular, square, or hexagonal shape. However, no regularity is observed in the arrangement of metal atoms between different pellets.

[0274] Next, C was analyzed by X-ray diffraction (XRD). Let's discuss AAC-OS. For example, CAAC-OS having an InGaZnO4 crystal. When structural analysis of S is performed using the out-of-plane method, the result is as shown in Figure 21(A). In some cases, a peak may appear near a diffraction angle (2θ) of 31°. This peak is in InGa Since it is attributed to the (009) plane of the ZnO4 crystal, the CAAC-OS crystal is c-axis oriented. It can be confirmed that it possesses this property, and that the c-axis is oriented in a direction approximately perpendicular to the surface to be formed or the upper surface.

[0275] In addition, in the structural analysis using the out-of-plane method of CAAC-OS, 2θ is 31 In addition to the peak near °, a peak may also appear when 2θ is near 36°. The nearby peak indicates that some of the crystals in CAAC-OS do not exhibit c-axis orientation. This shows that a more preferable CAAC-OS is structured using the out-of-plane method. The analysis shows that 2θ shows a peak near 31°, but does not show a peak near 36°.

[0276] On the other hand, in the CAAC-OS, X-rays are incident from a direction approximately perpendicular to the c-axis in an in-plane configuration. Structural analysis using the ne method reveals a peak near 2θ = 56°. This peak corresponds to I It is attributed to the (110) plane of the nGaZnO4 crystal. In the case of CAAC-OS, 2θ is 5 The sample is fixed at approximately 6° and analyzed while rotating it around the normal vector of the sample surface as the axis (φ axis). Even after performing a (φ scan), no clear peak appears, as shown in Figure 21(B). In contrast, with a single-crystal oxide semiconductor of InGaZnO4, if 2θ is fixed to around 56°, then φ When scanned, it is assigned to a crystal plane equivalent to the (110) plane, as shown in Figure 21(C). Six peaks are observed. Therefore, structural analysis using XRD indicates that CAAC-OS is It can be confirmed that the orientation of the a-axis and b-axis is irregular.

[0277] Next, we will explain CAAC-OS analyzed by electron diffraction. For example, InGa For CAAC-OS containing ZnO4 crystals, a probe with a diameter of 300 nm is used parallel to the sample surface. When the electron beam is incident, a diffraction pattern like the one shown in Figure 22(A) (limited field transmitted electron wave) is produced. This diffraction pattern may appear. (Also called a diffraction pattern.) The spot originates from the (009) plane of the crystal. Therefore, electron diffraction also reveals The pellets contained in CAAC-OS have c-axis orientation, and the c-axis is on the surface to be formed or the upper surface. It can be seen that it is oriented in a nearly perpendicular direction. On the other hand, for the same sample, when the probe is directed perpendicular to the sample surface... Figure 22(B) shows the diffraction pattern when an electron beam with a diameter of 300 nm is incident on the surface. From 2(B), a ring-shaped diffraction pattern is observed. Therefore, electron diffraction also shows It can be seen that the a-axis and b-axis of the pellets contained in CAAC-OS do not have orientation. Note that the first ring in Figure 22(B) is the (010) plane of the InGaZnO4 crystal. This is thought to be caused by the nominal (100) plane, etc. Also, the second ring in Figure 22(B) This is thought to be caused by (110) planes, etc.

[0278] As mentioned above, CAAC-OS is a highly crystalline oxide semiconductor. Crystallinity can decrease due to the inclusion of impurities or the formation of defects, so the opposite perspective is also possible. Therefore, CAAC-OS can be described as an oxide semiconductor with few impurities or defects (such as oxygen vacancies).

[0279] Impurities are elements other than the main components of oxide semiconductors, such as hydrogen, carbon, silicon, and transition gold. There are group elements, for example. For example, silicon and other metal elements that make up oxide semiconductors are more acidic than the metal elements that make up oxide semiconductors. Elements with strong bonding forces can remove oxygen from oxide semiconductors, thereby altering the atomic arrangement of the oxide semiconductor. This disrupts the crystallinity and reduces its properties. Also, heavy metals such as iron and nickel, and argon, Because carbon dioxide and other elements have large atomic radii (or molecular radii), the atomic arrangement of oxide semiconductors This disrupts the crystallinity and reduces its properties.

[0280] When oxide semiconductors contain impurities or defects, their properties may change due to light, heat, etc. Yes. For example, impurities contained in oxide semiconductors can act as carrier traps, or they can cause carriers to be trapped. It can sometimes be a source of rear emissions. Also, oxygen vacancies in oxide semiconductors can trap carriers. In some cases, it may become a carrier source by capturing hydrogen.

[0281] CAAC-OS, with its low impurity and oxygen vacancy rate, is suitable for oxide semiconductors with low carrier density. Yes, such oxide semiconductors are high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors. It is called CAAC-OS. CAAC-OS has a low impurity concentration and a low defect level density. In other words, it has stable properties. It can be said that it is an oxide semiconductor possessing [a certain characteristic].

[0282] <nc-os> Next, I will explain nc-OS.

[0283] nc-OS allows for the identification of crystalline regions in high-resolution TEM images, and It has regions where a definite crystalline portion cannot be identified. The crystalline portion contained in nc-OS is The size is often between 1 nm and 10 nm, or larger than 1 nm. Oxide semiconductors with a size greater than 10 nm and less than or equal to 100 nm are called microcrystalline oxide semiconductors. It is sometimes called this. nc-OS, for example, clearly identifies grain boundaries in high-resolution TEM images. It may not be possible to recognize it. Furthermore, the nanocrystals share the same origin as the pellets in CAAC-OS. There is a possibility of this happening. Therefore, in the following, the crystalline portion of nc-OS may be referred to as a pellet. be.

[0284] nc-OS is used in minute regions (for example, regions between 1 nm and 10 nm, especially regions larger than 1 nm). It has periodicity in the atomic arrangement in the region of 3 nm or less. In addition, nc-OS has different properties. No regularity is observed in the crystal orientation between the letts. Therefore, no orientation is observed throughout the entire film. Therefore, depending on the analytical method, nc-OS may be a-like OS or amorphous oxide semiconductor. It can sometimes be indistinguishable from the body. For example, nc-OS has a larger diameter than pellets. When using X-rays, out-of-plane analysis shows peaks indicating crystal planes. Not detected. Also, for nc-OS, a probe diameter larger than the pellet (e.g., 50 When electron diffraction is performed using an electron beam (of a magnitude greater than nm), a diffraction pattern similar to a halo pattern is obtained. Observed. On the other hand, compared to nc-OS, the pellet size is close to or smaller than the pellet size. When nanobeam electron diffraction is performed using an electron beam with a lobe diameter, spots can be observed. When nanobeam electron diffraction is performed on nc-OS, a high-brightness pattern is observed, forming a circular (ring-shaped) pattern. In some cases, a region may be observed. Furthermore, multiple spots may be observed within a ring-shaped region. There are cases where this occurs.

[0285] Thus, since there is no regularity in the crystal orientation between pellets (nanocrystals), nc -OS has RANC (Random Aligned nanocrystals) Oxide semiconductors, or NANC (Non-Aligned nanocrystals), It can also be called an oxide semiconductor having s).

[0286] nc-OS is an oxide semiconductor with higher orderliness than amorphous oxide semiconductors. nc-OS has a lower defect level density than a-like OS and amorphous oxide semiconductors. However, nc-OS does not show any regularity in crystal orientation between different pellets. Therefore, nc-OS has a higher defect level density compared to CAAC-OS.

[0287] <a-like OS> a-like OS is an oxide having a structure between nc-OS and amorphous oxide semiconductors. It is a semiconductor.

[0288] a-like OS may exhibit porosity in high-resolution TEM images. Furthermore, In the high-resolution TEM image, there are regions where the crystalline portion can be clearly identified, and regions where the crystalline portion can be clearly identified. It has areas that cannot be done.

[0289] Due to its porous nature, a-like OS has an unstable structure. Below, a-lik This demonstrates that e OS has a less stable structure compared to CAAC-OS and nc-OS. Therefore, it shows the structural changes caused by electron irradiation.

[0290] The samples to be irradiated with electrons are a-like OS (referred to as sample A) and nc-OS. Prepare (referred to as Sample B) and CAAC-OS (referred to as Sample C). This sample is also an In-Ga-Zn oxide.

[0291] First, high-resolution cross-sectional TEM images are obtained for each sample. It can be seen that all of the materials contain crystalline parts.

[0292] The determination of which part should be considered a single crystal can be made as follows. The unit cell of the InGaZnO4 crystal has three In-O layers and a Ga-Zn-O layer. It is known to have a structure in which a total of nine layers, consisting of six layers, are stacked in layers along the c-axis. The spacing between these adjacent layers is approximately the same as the spacing between the grid planes of the (009) plane (also called the d value). Therefore, the value has been determined to be 0.29 nm from crystal structure analysis. The areas where the spacing is between 0.28 nm and 0.30 nm are considered to be the crystalline parts of InGaZnO4. It can be considered as such. Furthermore, the lattice patterns correspond to the ab-plane of the InGaZnO4 crystal.

[0293] Figure 23 shows the average size of the crystalline regions (22 to 45 locations) in each sample. This is an example of investigating crystal size. However, the length of the grid pattern mentioned above is used. This is the size of the crystal. From Figure 23, a-like OS is the cumulative electron irradiation dose (Cu The crystalline portion grows larger in proportion to the mulative electron dose. This can be seen. Specifically, as shown in (1) in Figure 23, the odor in the initial stages of observation by TEM Initially, the crystalline region (also called the initial nucleus), which was about 1.2 nm in size, increased in size when the cumulative irradiation dose reached 4.2 ×10 8 e - / nm 2 In this case, it can be seen that it has grown to a size of about 2.6 nm. On the other hand, with nc-OS and CAAC-OS, the cumulative dose of electrons from the start of electron irradiation is 4 .2×10 8 e - / nm 2 Within this range, it was found that no change was observed in the size of the crystal portion. Specifically, as shown in (2) and (3) in Figure 23, the cumulative dose of electrons is used. The crystal size of nc-OS and CAAC-OS is approximately 1.4 nm, respectively. It can be seen that it is approximately 2.1 nm.

[0294] Thus, in a-like OS, crystalline growth can be observed upon electron irradiation. Yes. On the other hand, in nc-OS and CAAC-OS, the growth of the crystal portion by electron irradiation is almost entirely... It can be seen that it cannot be seen. In other words, a-like OS is nc-OS and CAAC- Compared to an operating system, it appears to have an unstable structure.

[0295] Furthermore, because it is porous, a-like OS is compared to nc-OS and CAAC-OS. All of them are low-density structures. Specifically, the density of a-like OS is low compared to single-layer structures of the same composition. The density of the crystal will be between 78.6% and 92.3%. Also, the density of nc-OS and CAA The density of C-OS is between 92.3% and 100% of the density of a single crystal of the same composition. Oxide semiconductors with a crystal density of less than 78% are inherently difficult to deposit into film.

[0296] For example, in an oxide semiconductor satisfying In:Ga:Zn=1:1:1 [atomic ratio], The density of single-crystal InGaZnO4 with a rhombohedral crystal structure is 6.357 g / cm³. 3 This is how it will be. For example, in an oxide semiconductor that satisfies In:Ga:Zn=1:1:1 [atomic ratio] The density of a-like OS is 5.0 g / cm³. 3 More than 5.9g / cm 3 It will be less than. For example, in an oxide semiconductor satisfying In:Ga:Zn=1:1:1 [atomic ratio] The densities of nc-OS and CAAC-OS are 5.9 g / cm³. 3 More than 6.3g / cm 3 It will be less than.

[0297] Note that single crystals with the same composition may not exist. In that case, a mixture of crystals with different compositions in any proportion may be used. By combining single crystals, the density equivalent to a single crystal at a desired composition can be estimated. This is possible. The density corresponding to a single crystal of the desired composition can be obtained by combining single crystals of different compositions. The proportion can be estimated using a weighted average. However, the density should be as small as possible. It is preferable to estimate by combining different types of single crystals.

[0298] As described above, oxide semiconductors can take on various structures, each possessing a variety of properties. Oxide semiconductors include, for example, amorphous oxide semiconductors, a-like OS, and nc-OS. The laminated film may have two or more types of CAAC-OS.

[0299] (Embodiment 4) In this embodiment, the display device having a transistor as illustrated in the previous embodiment An example will be explained below using Figures 24 to 26.

[0300] Figure 24 is a top view showing an example of a display device. The display device 700 shown in Figure 24 is the first A pixel section 702 provided on the substrate 701 and a source drive provided on the first substrate 701 The Pixel circuit section 704 and the gate driver circuit section 706, and the pixel section 702 and the source driver circuit A sealing material 712 is arranged to surround the path section 704 and the gate driver circuit section 706. It includes a second substrate 705 provided opposite the first substrate 701. The first substrate 701 and the second substrate 705 are sealed by a sealing material 712. The pixel section 702, the source driver circuit section 704, and the gate driver circuit section 706 are It is sealed by the first substrate 701, the sealing material 712, and the second substrate 705. Although not shown in Figure 24, a display element is provided between the first substrate 701 and the second substrate 705. It gets kicked.

[0301] Furthermore, the display device 700 is surrounded by a sealing material 712 on the first substrate 701. In a region different from the region, the pixel section 702, the source driver circuit section 704, and the gate driver are located. FPC terminal section 708 (FPC: Flexi) is electrically connected to circuit section 706. A FPC (Printed Circuit) is provided. Also, at the FPC terminal section 708 The FPC716 is connected, and the FPC716 controls the pixel unit 702 and the source driver circuit. Various signals are supplied to section 704 and gate driver circuit section 706. Also, pixel section 7 02, Source driver circuit section 704, Gate driver circuit section 706, and FPC terminal section 7 Wiring 710 is connected to each of 08. Various signals etc. are supplied by FPC716. The wiring 710 connects to the pixel unit 702, the source driver circuit unit 704, and the gate driver. This is provided to the circuit section 706 and the FPC terminal section 708.

[0302] Furthermore, the display device 700 may be provided with multiple gate driver circuit units 706. The device 700 includes a source driver circuit section 704 and a gate driver circuit section 706. Although an example is shown in which the pixel portion 702 is formed on the same first substrate 701, this configuration is not limited to this example. It is not necessary. For example, the gate driver circuit section 706 may be formed on the first substrate 701. Alternatively, only the source driver circuit section 704 may be formed on the first substrate 701. In this case, a substrate on which a source driver circuit or gate driver circuit, etc., is formed (for example, a single-wired board) A drive circuit board (formed from a crystalline semiconductor film or a polycrystalline semiconductor film) is mounted on the first substrate 701. This configuration is also acceptable. Furthermore, the method of connecting the separately formed drive circuit board is not particularly limited. Instead, methods such as COG (Chip On Glass) and wire bonding are used. You can use it.

[0303] Furthermore, the display device 700 includes a pixel section 702, a source driver circuit section 704, and a gate The driver circuit section 706 has multiple transistors, as described in Embodiment 2. A transistor can be applied.

[0304] Furthermore, the display device 700 may use various forms or have various display elements. This can be done. The display elements are, for example, liquid crystal elements, LEDs (white LEDs, red LEDs, green LEDs). EL (electroluminescent) elements (organic materials and) including EDs, blue LEDs, etc. EL elements containing inorganic materials, organic EL elements, inorganic EL elements), transistors (emitting current according to current) (Optical transistor), electron emission element, electrophoretic element, grating light bulb (G LV) and Digital Micromirror Device (DMD), DMS (Digital Micromirror Device) Shutter element, MIRASOL® display, IMOD (interference) MEMS (microphone) elements such as pulse modulation elements and piezoelectric ceramic displays. Display elements using electromechanical systems, electrowetting Examples include elements. In addition to these, contrast can be altered by electrical or magnetic effects. The display medium may have a display element and a display element. Quantum dots may also be used. An example of a display device using liquid crystal elements is a liquid crystal display. Play (transmissive liquid crystal display, semi-transmissive liquid crystal display, reflective liquid crystal display) Examples include direct-view liquid crystal displays and projection liquid crystal displays. An example of a display device is an EL display. One example is a field emission display (FED) or SED type flat panel display. Display (SED: Surface-conduction Electron-em) Examples include quantum dot displays. Examples include quantum dot displays. Display devices using electronic ink or electrophoretic elements. One example is electronic paper. Other examples include transflective liquid crystal displays and reflective liquid crystal displays. When realizing a display, some or all of the pixel electrodes are used as reflective electrodes. The goal is to make it functional. For example, some or all of the pixel electrodes are made of aluminum. It should have materials such as silver, etc. Furthermore, in that case, SRAM should be placed below the reflective electrode. It is also possible to incorporate memory circuits such as the following. This further reduces power consumption. It is possible.

[0305] The display method used in the display device 700 is either progressive or interlaced. These can be used. Also, when displaying in color, the color elements controlled by pixels include R It is not limited to the three colors GB (R stands for red, G for green, and B for blue). For example, if the pixels have R and G It may consist of four pixels: a pixel, a B pixel, and a W (white) pixel. Alternatively, a pentile arrangement. As shown in the column, two of the RGB colors make up one color element, and different two colors are used depending on the color element. You can select and configure colors. Alternatively, you can use RGB with one or more colors such as yellow, cyan, magenta. You may add more above. Note that the size of the display area for each dot of the color element may differ. However, the disclosed invention is not limited to a color display device, but also includes monochrome displays. It can also be applied to display devices.

[0306] Also, white light is used for backlights (organic EL elements, inorganic EL elements, LEDs, fluorescent lamps, etc.) In order to display full color on a display device using W), a color layer (also called a color filter) is used. .) may be used. The colored layer may be, for example, red (R), green (G), and blue (B). Yellow (Y) and other colors can be used in appropriate combinations. By using a colored layer, Compared to not using a colored layer, the color reproduction can be improved. In this case, the colored layer By arranging regions that have a colored layer and regions that do not have a colored layer, the region that does not have a colored layer White light may be used directly for display. A region without a colored layer may be placed in part. This reduces the decrease in brightness caused by the colored layer when displaying bright images, and can reduce power consumption by 20%. In some cases, this can be reduced by about 30%. However, this applies to self-emissive elements such as organic EL elements and inorganic EL elements. When displaying in full color using sub-elements, R, G, B, Y, and white (W) are used in their respective outputs. It is also acceptable to emit light from an element that has a light color. By using an autoluminescent element, a colored layer can be used. In some cases, power consumption can be reduced even further than in the previous scenario.

[0307] In this embodiment, a VA (vertically aligned) type liquid crystal element is used as the display element. The configuration of the device will be explained using Figures 25 and 26. The VA type refers to the liquid crystal display of the display device. It is a type of method for controlling the arrangement of molecules. VA-type liquid crystal display devices are used when voltage is applied. A normally black display device in which liquid crystal molecules are oriented perpendicular to the panel surface when not in use. The display device shown in this embodiment divides a single pixel into several sub-regions. The liquid crystal molecules are divided into pixels and tilted in different directions for each pixel. This is called multi-domainization or multi-domain design.

[0308] Figure 25 is a cross-sectional view of the dashed-dotted line QR shown in Figure 24. Display device shown in Figure 25 700 consists of a wiring section 711, a pixel section 702, and a source driver circuit section 704. It has an FPC terminal section 708 and a wiring section 711 which has wiring 710. Furthermore, the pixel section 702 has a transistor 750 and a capacitive element 790. The screwdriver circuit section 704 has a transistor 752.

[0309] Transistors 750 and 752 are the transistors shown in Embodiment 2. It is possible to be there.

[0310] The transistor used in this embodiment is made of an oxide that has been purified to suppress the formation of oxygen vacancies. It has a semiconductor film. The transistor reduces the current value in the off state (off current value). This allows for longer holding times of electrical signals such as image signals, and power supply When enabled, the write interval can also be set to a longer duration. Therefore, the frequency of refresh operations can be reduced. This allows for reduced power consumption.

[0311] Furthermore, the transistor used in this embodiment is capable of obtaining a relatively high field-effect mobility. Therefore, high-speed operation is possible. For example, a transistor capable of such high-speed operation can be used in a liquid crystal display. By using it in a display device, the switching transistors in the pixel section and the drive circuit section are used. Driver transistors can be formed on the same substrate. That is, they can be used as a separate drive circuit. Therefore, since there is no need to use semiconductor devices formed from silicon wafers, etc., This reduces the number of parts. In addition, the pixel section also has a transistor that can be driven at high speed. By using ZISTA, high-quality images can be provided.

[0312] Capacitive element 790 has a structure in which a dielectric is located between a pair of electrodes. More specifically, capacitive element One electrode of child 790 is a conductive film that functions as the gate electrode of transistor 750. Using a conductive film formed in the same process, the other electrode of the capacitive element 790 is a transient A conductive film is used that functions as the source electrode and drain electrode of the STA750. As a dielectric sandwiched between electrodes, it functions as the gate insulating film of transistor 750. Use an insulating film.

[0313] Also, in Figure 25, transistor 750, transistor 752, and capacitive element 79 Insulating films 764, 766, 768 and a planarizing insulating film 770 are provided on the 0.

[0314] The insulating films 764, 766, and 768 are the insulating film 514 shown in Embodiment 2, respectively. 516 and 518 can be formed using the same materials and manufacturing methods. Examples of insulating film 770 include polyimide resin, acrylic resin, polyimideamide resin, and benzo Use heat-resistant organic materials such as cyclobutene resin, polyamide resin, and epoxy resin. This can be achieved. Furthermore, by stacking multiple insulating films formed from these materials, planarization can be achieved. An insulating film 770 may be formed. Alternatively, the planarizing insulating film 770 may not be provided. .

[0315] Furthermore, the wiring 710 serves as the source and drain electrodes for transistors 750 and 752. It is formed using the same process as the conductive film that functions. Note that the wiring 710 is connected to the transistor 750. 752 The conductive film formed by a different process from the source electrode and drain electrode, for example, the gate electrode It may also be a conductive film that functions as an electrode. For example, the wiring 710 may be made of a material containing copper. When used, it reduces signal delays caused by wiring resistance, enabling display on a large screen.

[0316] Furthermore, the FPC terminal section 708 includes a connecting electrode 760, an anisotropic conductive film 780, and FPC 71 It has 6. The connecting electrode 760 is the source electrode of transistors 750 and 752 and It is formed using the same process as the conductive film that functions as a rain electrode. Also, the connecting electrode 760 is F The terminals on the PC716 are electrically connected via the anisotropic conductive film 780.

[0317] Furthermore, for example, glass substrates can be used as the first substrate 701 and the second substrate 705. This can be done. Also, the first substrate 701 and the second substrate 705 are as shown in Embodiment 2. The same material as that used for substrate 502 can be used.

[0318] On the second substrate 705 side, there is a light-shielding film 738 that functions as a black matrix, and a color A colored layer 736 that functions as a filter, and an insulating film in contact with the light-shielding film 738 and the colored layer 736. 734 will be established.

[0319] Furthermore, a structure 778 is provided between the first substrate 701 and the second substrate 705. The fabricated body 778 is a columnar spacer obtained by selectively etching an insulating film. It is provided to control the distance (cell gap) between the first substrate 701 and the second substrate 705. It is possible to use a spherical spacer as the structure 778.

[0320] Also, as shown in Figure 26, multiple colored layers 736 are stacked instead of the structure 778. A spacer may be used. The display device 700 shown in Figure 26 is, as an example, a red light It has a color layer 736R, a green colored layer 736G, and a blue colored layer 736B, and Colored layer 736G and colored layer 736B are placed on the colored layer 736R at a position overlapping with the light film 738. A such configuration is provided. This configuration eliminates the step of forming the structure 778. It is possible to do so. Furthermore, the display device 700 shown in Figure 26 has a configuration without an insulating film 734. The above spacers are colored layer 736R, colored layer 736G and colored layer 7 You may also use a stack of any two of the 36B materials.

[0321] Furthermore, in this embodiment, the structure 778 is provided on the first substrate 701 side. The examples given are not limited to these. For example, the structure 778 can be provided on the second substrate 705 side. A configuration in which the structure 778 is provided on both the first substrate 701 and the second substrate 705. It can be considered a success.

[0322] The display device 700 has a liquid crystal element 775. The liquid crystal element 775 has a conductive film 772, conductive It has a film 774 and a liquid crystal layer 776. The conductive film 774 is provided on the second substrate 705 side. , it functions as a counter electrode. The display device 700 has a conductive film 772 and a conductive film 774 The orientation of the liquid crystal layer 776 changes depending on the applied voltage, resulting in light transmission or opacity. The system is controlled and an image can be displayed. Protrusions 744 are provided on the conductive film 774.

[0323] Furthermore, the conductive film 772 serves as the source electrode and drain electrode of the transistor 750. It is connected to a conductive film that functions as a pixel. The conductive film 772 is formed on the planar insulating film 770 and is connected to the pixel. It functions as an electrode, i.e., one of the electrodes of the display element. Furthermore, the conductive film 772 is a reflective electrode. It has the function of a display device. The display device 700 uses ambient light and reflects the light with the conductive film 772 to display light. This is a so-called reflective color liquid crystal display device that displays images via 736 color layers.

[0324] The conductive film 772 is a conductive film that is transparent in visible light, or a conductive film that is transparent in visible light. A conductive film with light-transmitting properties can be used. Examples of conductive films that are transparent in visible light include: For example, a material containing one element selected from indium (In), zinc (Zn), and tin (Sn). It is advisable to use a material. Examples of conductive films that are reflective in visible light include aluminum. Alternatively, a material containing silver may be used. In this embodiment, the conductive film 772 is, A reflective conductive film is used in the visible light spectrum.

[0325] Furthermore, when a conductive film that is reflective in visible light is used as the conductive film 772, The film may also be in a layered structure. For example, an aluminum film with a thickness of 100 nm may be formed as the lower layer. A 30 nm thick silver alloy film (for example, an alloy film containing silver, palladium, and copper) is formed on the upper layer. The above structure provides the following excellent effects.

[0326] (1) The adhesion between the base film and the conductive film 772 can be improved. (2) By using a chemical solution It is possible to etch both the aluminum film and the silver alloy film at the same time. (3) Conductive The cross-sectional shape of the film 772 can be made into a good shape (for example, a tapered shape). (3) The reason for this is that aluminum films have a slower etching rate with chemicals than silver alloy films. Alternatively, if the lower aluminum film is exposed after etching of the upper silver alloy film, the silver alloy Electrons are drawn from aluminum, a metal that is less noble than the film, or in other words, a metal with a high ionization tendency. To achieve this, etching of the silver alloy film is suppressed, and etching of the underlying aluminum film progresses. This is because it speeds up the writing process.

[0327] The display device 700 shown in Figures 25 to 27 is a reflective color liquid crystal display device. The examples given are not limited to these. For example, the conductive film 772 may be transparent in visible light. By using a certain conductive film, it may also be used as a transmissive color liquid crystal display device. Display device 700 In the case of a transmissive liquid crystal display device, the pair of electrodes of the capacitive element 790 are connected to the conductive film 772 It is positioned so as not to overlap with the substrate 701 and the liquid crystal element 775 and the colored layer 73. Each layer in the path of light emitted via 6 is made of a layer that is transparent to visible light. It is preferable to do so.

[0328] The conductive film 772 has a slit 725. The slit 725 controls the orientation of the liquid crystal molecules. This is for the purpose of oriented A film 746 is provided, and similarly, an alignment film 748 is provided on the conductive film 774.

[0329] When a voltage is applied to the conductive film 772 with the slit 725, near the slit 725 A distortion of the electric field (oblique electric field) occurs. This is due to the slit 725 and the protrusion 744 on the substrate 705 side. By arranging them so that they interlock alternately, an oblique electric field is effectively generated to align the liquid crystal. It is controlled so that the orientation of the liquid crystals differs depending on the location. In other words, one pixel By tilting the liquid crystal molecules in a different direction for each of the multiple subpixels it possesses, it becomes multi-domain. The viewing angle of the LCD display panel has been widened.

[0330] Although not shown in Figure 25, optical components such as polarizing members, phase difference members, and anti-reflective members are also included. Components (optical substrates, etc.) may be provided as appropriate. For example, circular polarization using a polarizing substrate and a phase difference substrate. Light may be used. Furthermore, backlights, sidelights, etc., may be used as light sources.

[0331] The configuration shown in this embodiment may be used in appropriate combination with the configurations shown in other embodiments. It is possible.

[0332] (Embodiment 5) In this embodiment, a display module and electronic device having a semiconductor device according to one aspect of the present invention are provided. This will be explained using Figures 27 and 28.

[0333] The display module 8000 shown in Figure 27 consists of an upper cover 8001 and a lower cover 8002. In between, the touch panel 8004 connected to the FPC8003 and the FPC8005 are connected. Display panel 8006, backlight 8007, frame 8009, printed circuit board 801 0, has battery 8011.

[0334] A display device according to one aspect of the present invention can be used, for example, as a display panel 8006.

[0335] The upper cover 8001 and the lower cover 8002 are the touch panel 8004 and the display panel. The shape and dimensions can be appropriately modified to match the size of the 8006.

[0336] The touch panel 8004 is a display panel using either a resistive or capacitive touch panel. It can be used superimposed on 8006. Also, the opposing substrate (sealing substrate) of the display panel 8006 It is also possible to give the board a touch panel function. It is also possible to install a light sensor in each pixel of 006 to create an optical touch panel.

[0337] The backlight 8007 has a light source 8008. Note that in Figure 27, the backlight The example given shows a configuration in which the light source 8008 is placed on the T8007, but it is not limited to this. For example, a light source 8008 is placed at the edge of the backlight 8007, and a light diffuser plate is also used. It may also be made into a component. Furthermore, when using self-emissive light-emitting elements such as organic EL elements, or when using reflection In the case of type panels, etc., a configuration without backlight 8007 is also acceptable.

[0338] Frame 8009 provides protection for the display panel 8006, as well as the movement of the printed circuit board 8010. It has the function of an electromagnetic shield to block electromagnetic waves generated by the operation. The 8009 may also function as a heat sink.

[0339] The printed circuit board 8010 contains power supply circuits and signals for outputting video and clock signals. It has a power processing circuit. The power supply that provides power to the power supply circuit is an external commercial power supply. Alternatively, a separate power source, the battery 8011, may also be used. This can be omitted when using commercial power.

[0340] Furthermore, the display module 8000 includes components such as polarizing plates, phase difference plates, and prism sheets. They may also be provided.

[0341] Figures 28(A) to 28(G) show electronic devices. These electronic devices are enclosed in a housing. Body 5000, display unit 5001, speaker 5003, LED lamp 5004, operation keys 50 05 (including power switch or operation switch), connection terminal 5006, sensor 5007 ( Force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances , sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor It may have a microphone 5008 (or a device that includes a function to measure infrared rays), etc. can.

[0342] Figure 28(A) shows a mobile computer, and in addition to the above, it also has a switch 5009 It may have an infrared port 5010, etc. Figure 28(B) shows a portable recording device equipped with a recording medium. A strip-type image playback device (for example, a DVD player), and in addition to those mentioned above, see Table 2. It may have a display unit 5002, a recording medium reading unit 5011, etc. Figure 28(C) is a Go It is a group-type display, and in addition to the above, it includes a second display unit 5002 and a support unit 5012 It may have earphones 5013, etc. Figure 28(D) is a portable gaming machine, and above In addition to those described above, it may also have a recording medium reading unit 5011, etc. Figure 28(E) It is a digital camera with a television receiving function, and in addition to the above, it has an antenna 5014, It may have a shutter button 5015, an image receiving unit 5016, etc. Figure 28(F) is a portable It is a band-type gaming machine, and in addition to the above, it also has a second display unit 5002 and a recording medium reading unit 5011. , etc. Figure 28(G) is a portable television receiver, and the above-mentioned In addition, it may have a charger 5017 capable of transmitting and receiving signals, etc.

[0343] The electronic devices shown in Figures 28(A) to 28(G) can have a variety of functions. For example, a function that displays various information (still images, videos, text images, etc.) on the display unit, Panel functions, calendar, date or time display functions, various software ( A function that controls processing by program, wireless communication function, and various functions using wireless communication function. Functions to connect to computer networks, and to transmit various data using wireless communication functions or The function of receiving data, reading programs or data recorded on the recording medium and displaying them on the display unit. It can have a display function, etc. Furthermore, in electronic devices having multiple display units In this system, one display unit primarily displays image information, and another display unit primarily displays text information. A function to display a three-dimensional image, or by displaying images that take parallax into account on multiple display units. It can have functions such as displaying images. Furthermore, in electronic devices having an image receiving unit... For example, it has functions for taking still images, recording videos, and automatically or manually enhancing the captured images. Correction function, function to save captured images to a recording medium (external or built into the camera), capture It can have functions such as displaying the image on the display unit. The functions that electronic devices shown in 8(G) may have are not limited to these, and may include a variety of functions. It is possible to have.

[0344] The electronic device described in this embodiment has a display unit for displaying some kind of information. The display unit can be fitted with the display device shown in Embodiment 4. ru.

[0345] The configuration shown in this embodiment may be used in appropriate combination with the configurations shown in other embodiments. It is possible. [Explanation of symbols]

[0346] 100 pixels 101 circuit board 103 scan lines 105a Capacity Wiring 105b Capacitive Wiring 107 Gate Insulator 107a gate insulator 107b Gate Insulator 114 Insulating Film 116 Insulating film 116a insulating film 116b insulating film 116c insulating film 121 Signal Line 123 Electrode 125a electrode 125b electrode 135 Semiconductor film 135a Oxide semiconductor film 135b Oxide semiconductor film 136 transistors 137 transistors 139a Pixel electrode 139b Pixel electrode 140 Capacitive elements 141 Capacitive elements 142 liquid crystal elements 143 liquid crystal elements 144a aperture 144b aperture 145 Capacitive element 146 Capacitive elements 148 pixel electrodes 148a Oxide conductive film 148b Oxide conductive film 149 Pixel electrodes 200 pixels 203 scan lines 221 Signal Line 223a electrode 223b Electrode 236 transistors 237 transistors 300 pixels 301 circuit board 303 scan lines 305a capacitive wiring 305b capacitor wiring 307 Gate Insulator 316 Insulating film 321 signal line 323a electrode 323b electrode 325a electrode 325b electrode 335 Semiconductor film 336 transistors 337 transistors 339a Pixel electrode 339b Pixel electrode 340 Capacitive elements 341 Capacitive element 342 liquid crystal elements 343 liquid crystal elements 344a aperture 344b aperture 345a electrode 345b electrode 346a aperture 346b aperture 500 transistors 502 circuit board 504 Conductive film 506 Insulating film 507 Insulating film 508 Oxide semiconductor film 508a Oxide Semiconductor Film 508b oxide semiconductor film 509 Oxide semiconductor film 509a Oxide semiconductor film 509b oxide semiconductor film 512 Conductive film 512a Conductive film 512b Conductive film 514 Insulating film 516 Insulating film 518 Insulating Film 519 Insulating film 520 Conductive film 520a conductive film 520b Conductive film 531 Barrier film 536a Mask 536b Mask 538 Etchant 539 Etchant 540 Oxygen 540a Oxygen 542 Etchant 542a opening 542b opening 542c opening 570 transistors 700 Display device 701 circuit board 702 pixel section 704 Source Driver Circuit 705 circuit board 706 Gate Driver Circuit Section 708 FPC terminal section 710 Wiring 711 Wiring section 712 Sealant 716 FPC 725 Slit 734 Insulating Film 736 Colored layer 736B Colored layer 736G colored layer 736R colored layer 738 Light-shielding film 744 Protrusion 746 Alignment film 748 Alignment film 750 transistors 752 transistors 760 connecting electrodes 764 Insulating Film 766 Insulating film 768 Insulating film 770 Planarizing Insulator 772 Conductive film 774 Conductive film 775 liquid crystal elements 776 Liquid Crystal Layer 778 Structure 780 Anisotropic conductive film 790 Capacitive elements 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED Lamp 5005 Operation Keys 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared Port 5011 Recording medium reading unit 5012 Support part 5013 Earphones 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 5100 pellets 5120 circuit board 5161 area 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8007 Backlight 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

1. The pixel portion comprises at least a first pixel electrode, a second pixel electrode, a third pixel electrode, a first transistor electrically connected to the first pixel electrode, a second transistor electrically connected to the second pixel electrode, a first capacitive element electrically connected to the first pixel electrode, a second capacitive element electrically connected to the second pixel electrode, and a third capacitive element electrically connected to the third pixel electrode. A first conductive layer having a region extending in a first direction, having the function of a gate electrode of the first transistor and the function of a gate electrode of the second transistor, A second conductive layer having a region that extends in a second direction intersecting the first direction, having the function of one of the source electrode and drain electrode of the first transistor and the function of one electrode of the first capacitive element, A third conductive layer having the function of being the other of the source electrode and drain electrode of the first transistor, and the function of being a signal line, A fourth conductive layer having the same material as the first conductive layer and functioning as the other electrode of the first capacitive element, A fifth conductive layer having a region that overlaps with the fourth conductive layer, and having the function of one of the source and drain electrodes of the second transistor, and the function of one electrode of the second capacitive element, A sixth conductive layer having a region in contact with the fourth conductive layer and a region intersecting with the first conductive layer, A first insulating layer having a region in contact with the upper surface of the first conductive layer and a region in contact with the upper surface of the conductive layer of the fourth conductive layer, The second insulating layer has a region in contact with the upper surface of the second conductive layer, a region in contact with the upper surface of the third conductive layer, and a region in contact with the fifth conductive layer. The first pixel electrode and the second pixel electrode are arranged adjacent to each other in the first direction. The first pixel electrode and the third pixel electrode are arranged adjacent to each other in the second direction. The first pixel electrode is electrically connected to the second conductive layer through the first opening of the second insulating layer. The second pixel electrode is electrically connected to the fifth conductive layer through the second opening of the second insulating layer. The fourth conductive layer functions as the other electrode of the second capacitive element. The sixth conductive layer functions as wiring that electrically connects the third capacitive element and the first capacitive element. A display device wherein the sixth conductive layer does not have an area that overlaps with the third conductive layer.

2. The pixel portion comprises at least a first pixel electrode, a second pixel electrode, a third pixel electrode, a first transistor electrically connected to the first pixel electrode, a second transistor electrically connected to the second pixel electrode, a first capacitive element electrically connected to the first pixel electrode, a second capacitive element electrically connected to the second pixel electrode, and a third capacitive element electrically connected to the third pixel electrode. A first conductive layer having a region extending in a first direction, having the function of a gate electrode of the first transistor and the function of a gate electrode of the second transistor, A second conductive layer having a region that extends in a second direction intersecting the first direction, having the function of one of the source electrode and drain electrode of the first transistor and the function of one electrode of the first capacitive element, A third conductive layer having the function of being the other of the source electrode and drain electrode of the first transistor, and the function of being a signal line, A fourth conductive layer having the same material as the first conductive layer and functioning as the other electrode of the first capacitive element, A fifth conductive layer having a region that overlaps with the fourth conductive layer, and having the function of one of the source and drain electrodes of the second transistor, and the function of one electrode of the second capacitive element, A sixth conductive layer having a region in contact with the fourth conductive layer and a region intersecting with the first conductive layer, A first insulating layer having a region in contact with the upper surface of the first conductive layer and a region in contact with the upper surface of the conductive layer of the fourth conductive layer, The second insulating layer has a region in contact with the upper surface of the second conductive layer, a region in contact with the upper surface of the third conductive layer, and a region in contact with the fifth conductive layer. The first pixel electrode and the second pixel electrode are arranged adjacent to each other in the first direction. The first pixel electrode and the third pixel electrode are arranged adjacent to each other in the second direction. The first pixel electrode is electrically connected to the second conductive layer through the first opening of the second insulating layer. The second pixel electrode is electrically connected to the fifth conductive layer through the second opening of the second insulating layer. The fourth conductive layer functions as the other electrode of the second capacitive element. The sixth conductive layer functions as wiring that electrically connects the third capacitive element and the first capacitive element. The sixth conductive layer does not have a region that overlaps with the third conductive layer. A display device wherein the fourth conductive layer overlaps with the first opening.

3. In claim 1 or 2, The pixel portion comprises a liquid crystal layer located above the first pixel electrode, and a counter electrode located above the liquid crystal layer and overlapping with the first pixel electrode, in a display device.

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