Semiconductor device

Abstract

To reduce the number of masks or the number of steps for a semiconductor device.SOLUTION: In a semiconductor device 100, a transistor Tr1 has: a first gate electrode 104; a first insulating film 106 thereon; a first oxide semiconductor film 108 thereon; a first source electrode and a drain electrode 112a and 112b on the first oxide semiconductor film; second insulating films 114 and 116 on the first oxide semiconductor film, the first source electrode and the drain electrode; and a second gate electrode 122c thereon, and a transistor Tr2 has: a first drain electrode; a second insulating film on the first drain electrode; a second oxide semiconductor film 128 on the second insulating film; a second source electrode and a second drain electrode 122a and 122b thereon; third insulating films 124 and 126 on the second oxide semiconductor film, the second source electrode and the drain electrode; and a third gate electrode 130 thereon. The first oxide semiconductor film and the second oxide semiconductor film hae regions overlapping with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention is a semiconductor device including an oxide semiconductor film and a display device including the semiconductor device. Regarding the device.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one aspect of the present invention relates to a product, a method, or a manufacturing method. Process, Machine, Manufacture, or Composition of Matter In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, The present invention relates to a device, a driving method thereof, or a manufacturing method thereof.

[0003] In this specification and the like, a semiconductor device is a device that can function by utilizing semiconductor characteristics. Refers to devices in general, including semiconductor elements such as transistors, semiconductor circuits, arithmetic units, and memory The device is one aspect of a semiconductor device. Optical devices, power generation devices (including thin-film solar cells, organic thin-film solar cells, etc.), and electronic devices The device may include a semiconductor device. [Background technology]

[0004] A transistor (field-effect transistor) is made using a semiconductor thin film formed on a substrate with an insulating surface. The technology that makes up the field-effect transistor (FET) or thin-film transistor (TFT) is attracting attention. The transistor is used in integrated circuits (ICs) and image display devices (display devices). It is widely used in electronic devices. Silicon is a semiconductor thin film that can be used in transistors. Semiconductor materials, such as silicon, are widely known, but oxide semiconductors are also attracting attention. is aimed at.

[0005] For example, in Patent Document 1, a first transistor using an oxide semiconductor film and a second transistor using an oxide semiconductor film are stacked to provide a plurality of overlapping memory cells, thereby disclosing a technique for reducing the cell area. By stacking a second transistor using an oxide semiconductor film, a plurality of memory cells are provided in a stacked manner, thereby disclosing a technique for reducing the cell area. A technique for reducing the cell area is disclosed by stacking a plurality of memory cells.

[0006] Further, in Patent Document 2, a pixel portion having a plurality of two-dimensionally arranged pixels and a drive circuit portion for driving the plurality of pixels are provided. A first layer including the drive circuit portion and a second layer including the pixel portion are stacked, thereby reducing the arrangement space of the drive circuit portion in the peripheral region of the pixel portion. A technique is disclosed. A pixel portion having a plurality of two-dimensionally arranged pixels and a drive circuit portion for driving the plurality of pixels are provided. A first layer including the drive circuit portion and a second layer including the pixel portion are stacked, thereby reducing the arrangement space of the drive circuit portion in the peripheral region of the pixel portion. A technique is disclosed. A technique is disclosed in which a first layer including the drive circuit portion and a second layer including the pixel portion are stacked to reduce the arrangement space of the drive circuit portion in the peripheral region of the pixel portion. A technique for reducing the arrangement space of the drive circuit portion in the peripheral region of the pixel portion is disclosed.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] As shown in Patent Documents 1 and 2, by stacking a plurality of transistors, the arrangement area of the transistors can be reduced. On the other hand, there is a problem that the number of mask sheets or the number of processes increases when a plurality of transistors are stacked. By stacking a plurality of transistors, the arrangement area of the transistors can be reduced. On the other hand, there is a problem that the number of mask sheets or the number of processes increases when a plurality of transistors are stacked. There is a problem that the number of mask sheets or the number of processes increases when a plurality of transistors are stacked.

[0009] In view of the above problems, one aspect of the present invention is to provide a semiconductor device in which a plurality of transistors are stacked, and one of the problems is to provide a semiconductor device with a small increase in the number of mask sheets or the number of processes. In view of the above problems, one aspect of the present invention is to provide a semiconductor device in which a plurality of transistors are stacked, and one of the problems is to provide a semiconductor device with a small increase in the number of mask sheets or the number of processes. Or, one aspect of the present invention is to stack a plurality of transistors having oxide semiconductor films. In a semiconductor device, it is one of the problems to provide a semiconductor device with a small increase in the number of mask sheets or processes. Or, one aspect of the present invention is to provide a novel semiconductor device as one of the problems. One of the problems is as follows.

[0010] Note that the description of the above problems does not prevent the existence of other problems. Note that one aspect of the present invention does not necessarily need to solve all of these problems. Other problems will be apparent from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like. One aspect of the present invention does not necessarily need to solve all of these problems. Other problems will be apparent from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like. Other problems will be apparent from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like. Other problems will be apparent from the description in the specification and the like, and it is possible to extract other problems from the description in the specification and the like.

Means for Solving the Problems

[0011] One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. The second transistor includes a first drain electrode, a second insulating film on the first drain electrode, a second oxide semiconductor film on the second insulating film, a second source electrode on the second oxide semiconductor film, a second drain electrode on the second oxide semiconductor film, a third insulating film on the second oxide semiconductor film, the second source electrode, and the second drain electrode, and a third gate electrode on the third insulating film. The first oxide semiconductor film and the second oxide semiconductor film... One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. One aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film. A semiconductor film is a semiconductor device having regions overlapping with each other.

[0012] Another aspect of the present invention is a semiconductor device including a first transistor and a second transistor, wherein the first transistor includes a first gate electrode, a first insulating film on the first gate electrode, a first oxide semiconductor film on the first insulating film, a first source electrode on the first oxide semiconductor film, a first drain electrode on the first oxide semiconductor film, a second insulating film on the first oxide semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film; and the second transistor includes a third gate electrode on the first insulating film, a second insulating film on the third gate electrode, a second oxide semiconductor film formed on the second insulating film and having a channel region, a source region, and a drain region, a third insulating film in contact with the channel region, a fourth gate electrode in contact with the third insulating film, a fourth insulating film in contact with the source region, the drain region, and the fourth gate electrode, a second source electrode electrically connected to the source region, and a second drain electrode electrically connected to the drain region; and the first oxide semiconductor film and the second oxide semiconductor film have regions overlapping with each other. The semiconductor device is as described above.

[0013] In the above aspect, it is preferable that the first gate electrode and the second gate electrode are connected at an opening provided in the first insulating film and the second insulating film, and have a region located outside the side end portion of the first oxide semiconductor film.

[0014] In the above aspect, it is preferable that at least one of the first oxide semiconductor film and the second oxide semiconductor film One or both of them preferably have In, Zn, and M (where M is Al, Ga, Y, or Sn). It is preferable.

[0015] Also, in the above aspect, the atomic ratio of In, M, and Zn is preferably around In:M:Zn = 4:2:3. When In is 4, M is preferably 1.5 or more and 2.5 or less, and Zn is preferably 2 or more and 4 or less. It is preferable that when In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more and 4 or less. It is preferable.

[0016] Also, in the above aspect, one or both of the first oxide semiconductor film and the second oxide semiconductor film preferably have a crystalline part, and the crystalline part preferably has c-axis orientation. It is preferable that the crystalline part has c-axis orientation.

[0017] Another aspect of the present invention is a semiconductor device having a first transistor and a second transistor. The first transistor includes a first oxide semiconductor film, a first insulating film on the first oxide semiconductor film, a first conductive film having a region overlapping the first oxide semiconductor film with the first insulating film interposed therebetween, a second insulating film on the first oxide semiconductor film and on the first conductive film, a second conductive film on the first oxide semiconductor film, a third conductive film on the first oxide semiconductor film, and a third insulating film on the first oxide semiconductor film, on the second conductive film, and on the third conductive film. The first oxide semiconductor film has a channel region in contact with the first insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second transistor includes a third conductive film, a third insulating film on the third conductive film, a second oxide semiconductor film on the third insulating film, a fourth conductive film on the second oxide semiconductor film, and a fifth conductive film on the second oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film have a region overlapping each other. The first transistor includes a first oxide semiconductor film, a first insulating film on the first oxide semiconductor film, a first conductive film having a region overlapping the first oxide semiconductor film with the first insulating film interposed therebetween, a second insulating film on the first oxide semiconductor film and on the first conductive film, a second conductive film on the first oxide semiconductor film, a third conductive film on the first oxide semiconductor film, and a third insulating film on the first oxide semiconductor film, on the second conductive film, and on the third conductive film. The first oxide semiconductor film has a channel region in contact with the first insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second transistor includes a third conductive film, a third insulating film on the third conductive film, a second oxide semiconductor film on the third insulating film, a fourth conductive film on the second oxide semiconductor film, and a fifth conductive film on the second oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film have a region overlapping each other. The first oxide semiconductor film has a channel region in contact with the first insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second transistor includes a third conductive film, a third insulating film on the third conductive film, a second oxide semiconductor film on the third insulating film, a fourth conductive film on the second oxide semiconductor film, and a fifth conductive film on the second oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film have a region overlapping each other. The second transistor includes a third conductive film, a third insulating film on the third conductive film, a second oxide semiconductor film on the third insulating film, a fourth conductive film on the second oxide semiconductor film, and a fifth conductive film on the second oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film have a region overlapping each other. The first oxide semiconductor film and the second oxide semiconductor film have a region overlapping each other. It is a semiconductor device having a region where the first oxide semiconductor film and the second oxide semiconductor film overlap each other.

[0018] Another embodiment of the present invention is a semiconductor device having a first transistor and a second transistor. A semiconductor device, wherein a first transistor includes a first oxide semiconductor film and a first oxide semiconductor film. A first insulating film on the conductive film and a region overlapping with the first oxide semiconductor film with the first insulating film sandwiched therebetween. a first conductive film having a region, a second insulating film on the first oxide semiconductor film, and a second insulating film on the first conductive film; a second conductive film on the first oxide semiconductor film; and a third conductive film on the first oxide semiconductor film. a third insulating film over the first oxide semiconductor film, the second conductive film, and the third conductive film; the first oxide semiconductor film has a channel region in contact with the first insulating film and a second insulating film a source region in contact with the insulating film and a drain region in contact with the second insulating film, The transistor includes a third conductive film, a third insulating film on the third conductive film, and a second insulating film on the third insulating film. a fourth conductive film over the second oxide semiconductor film; the fifth conductive film over the second oxide semiconductor film, the fourth conductive film over the fifth conductive film, and the fourth conductive film over the second oxide semiconductor film. a first insulating film and a second insulating film, the first insulating film and the second oxide semiconductor film being overlapped with each other with a fourth insulating film interposed therebetween; and a conductive film (6), and the first oxide semiconductor film and the second oxide semiconductor film overlap each other. The semiconductor device has a region.

[0019] Another embodiment of the present invention is a semiconductor device having a first transistor and a second transistor. A semiconductor device, wherein a first transistor includes a first oxide semiconductor film and a first oxide semiconductor film. A first insulating film on the conductive film and a region overlapping with the first oxide semiconductor film with the first insulating film sandwiched therebetween. a first conductive film having a region, a second insulating film on the first oxide semiconductor film, and a second insulating film on the first conductive film; The gate insulating film, the second conductive film on the first oxide semiconductor film, the third conductive film on the first oxide semiconductor film, and the third insulating film on the first oxide semiconductor film, on the second conductive film, and on the third conductive film And the first oxide semiconductor film has a channel region in contact with the first insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second transistor Has a third conductive film, a third insulating film on the third conductive film, a second oxide semiconductor film on the third insulating film, a fourth conductive film on the second oxide semiconductor film, a fifth conductive film on the second oxide semiconductor film, a fourth insulating film on the second oxide semiconductor film, and a sixth conductive film having a region overlapping the second oxide semiconductor film with the fourth insulating film interposed therebetween, and a fifth insulating film on the second oxide semiconductor film and on the sixth conductive film. The second oxide semiconductor film has a channel region in contact with the fourth insulating film, a source region in contact with the fifth insulating film, and a drain region in contact with the fifth insulating film. The semiconductor device has a region where the first oxide semiconductor film and the second oxide semiconductor film overlap each other. In each of the above configurations, it is preferable that one or both of the first oxide semiconductor film and the second oxide semiconductor film contain In, M (where M is Al, Ga, Y, or Sn), and Zn. Further, in each of the above configurations, the atomic ratio of In, M, and Zn is preferably in the vicinity of In:M:Zn = 4:2:3. When In is 4, M is preferably 1.5 or more and 2.5 or less, and Zn is preferably 2 or more and 4 or less. In each of the above configurations, either the first oxide semiconductor film or the second oxide semiconductor film contains In, M (where M is Al, Ga, Y, or Sn), and Zn. Further, in each of the above configurations, the atomic ratio of In, M, and Zn is in the vicinity of In:M:Zn = 4:2:3. When In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more and 4 or less. In each of the above configurations, either the first oxide semiconductor film or the second oxide semiconductor film contains In, M (where M is Al, Ga, Y, or Sn), and Zn. Further, in each of the above configurations, the atomic ratio of In, M, and Zn is in the vicinity of In:M:Zn = 4:2:3. When In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more and 4 or less. In each of the above configurations, either the first oxide semiconductor film or the second oxide semiconductor film contains In, M (where M is Al, Ga, Y, or Sn), and Zn. Further, in each of the above configurations, the atomic ratio of In, M, and Zn is in the vicinity of In:M:Zn = 4:2:3. When In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more and 4 or less. Is a semiconductor device having a region where they overlap each other.

[0020] In each of the above configurations, it is preferable that one or both of the first oxide semiconductor film and the second oxide semiconductor film contain In, M (where M is Al, Ga, Y, or Sn), and Zn. Further, in each of the above configurations, the atomic ratio of In, M, and Zn is preferably in the vicinity of In:M:Zn = 4:2:3. When In is 4, M is preferably 1.5 or more and 2.5 or less, and Zn is preferably 2 or more and 4 or less. Preferably.

[0021] Further, in each of the above configurations, the atomic ratio of In, M, and Zn is preferably in the vicinity of In:M:Zn = 4:2:3. When In is 4, M is preferably 1.5 or more and 2.5 or less, and Zn is preferably 2 or more and 4 or less. :2:3, and when In is 4, M is 1.5 or more and 2.5 or less, and Zn is 2 or more and 4 or less. Preferably.

[0022] In each of the above configurations, either the first oxide semiconductor film or the second oxide semiconductor film Either one or both has a crystalline part, and the crystalline part preferably has c-axis orientation.

[0023] Another aspect of the present invention is a display device including the semiconductor device according to any one of the above aspects and a light-emitting element. The light-emitting element preferably contains an organic compound, and the organic compound preferably contains a polymer compound.

[0024] Another aspect of the present invention is a display module including the above display device and a touch sensor. Another aspect of the present invention is an electronic apparatus including the semiconductor device according to any one of the above aspects, the above display device, or the above display module, and an operation key or a battery.

Advantages of the Invention

[0025] According to one aspect of the present invention, in a semiconductor device in which a plurality of transistors are stacked, a semiconductor device with a small increase in the number of masks or processes can be provided. Alternatively, according to one aspect of the present invention, in a semiconductor device in which a plurality of transistors having an oxide semiconductor film are stacked, a semiconductor device with a small increase in the number of masks or processes can be provided. Alternatively, according to one aspect of the present invention, a novel semiconductor device can be provided.

[0026] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that other effects will be apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0027] [Figure 1] A diagram for explaining the top surface and cross-section of a semiconductor device. [Figure 2] A diagram for explaining the circuit of a semiconductor device. [Figure 3] A diagram for explaining the cross-section of a semiconductor device. [Figure 4] A diagram for explaining the cross-section of a semiconductor device. [Figure 5] A diagram for explaining the cross-section of a semiconductor device. [Figure 6] A diagram for explaining the cross-section of a semiconductor device. [Figure 7] A diagram for explaining the energy band. [Figure 8] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 9] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 10] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 11] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 12] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 13] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 14] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 15] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 16] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 17] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 18] A diagram for explaining the top surface and cross-section of a semiconductor device. [Figure 19] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 20] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 21] Top view and cross-sectional view for explaining the manufacturing method of a semiconductor device. [Figure 22] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 23] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 24] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 25] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 26] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 27] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 28] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 29] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 30] Diagram for explaining the top and cross-section of a semiconductor device. [Figure 31] Diagram for explaining the circuit of a semiconductor device. [Figure 32] Diagram for explaining the cross-section of a semiconductor device. [Figure 33] Diagram for explaining the cross-section of a semiconductor device. [Figure 34] Diagram for explaining the cross-section of a semiconductor device. [Figure 35] Diagram for explaining the energy band. [Figure 36] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 37] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 38] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 39] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 40] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 41] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 42] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 43] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 44] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 45] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 46] Diagram for explaining the top surface and cross-section of a semiconductor device. [Figure 47] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 48] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 49] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 50] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 51] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 52] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 53] Top view and cross-sectional view for explaining a method of manufacturing a semiconductor device. [Figure 54] Schematic cross-sectional view of a light-emitting element. [Figure 55] Schematic cross-sectional view for explaining a method of manufacturing an EL layer. [Figure 56] Conceptual diagram for explaining a droplet discharge device. [Figure 57] Diagram for explaining the range of the atomic ratio of an oxide semiconductor. [Figure 58] Diagram for explaining the crystal of InMZnO4. [Figure 59] Diagram for explaining the energy band in a transistor using an oxide semiconductor in a channel region. [Figure 60] Diagram for explaining the structural analysis by XRD of CAAC-OS and single-crystalline oxide semiconductor, and diagram showing the selected-area electron diffraction pattern of CAAC-OS. [Figure 61] Cross-sectional TEM image of CAAC-OS, and plan-view TEM image and its image analysis image. [Figure 62]Diagram showing the electron diffraction pattern of nc-OS and cross-sectional TEM image of nc-OS. [Figure 63] Cross-sectional TEM image of a-like OS. [Figure 64] Diagram showing the change in the crystalline part due to electron irradiation of In-Ga-Zn oxide. [Figure 65] Top view showing one aspect of the display device. [Figure 66] Cross-sectional view showing one aspect of the display device. [Figure 67] Cross-sectional view showing one aspect of the display device. [Figure 68] Block diagram explaining the display device. [Figure 69] Diagram explaining the display module. [Figure 70] Diagram explaining the electronic device. [Figure 71] Diagram explaining the electronic device. [Figure 72] Perspective view explaining the display device.

Mode for Carrying Out the Invention

[0028] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different ways, and it is easily understood by those skilled in the art that the form and details can be variously changed without departing from the spirit and its scope. Therefore, the present invention is not construed as being limited to the description content of the following embodiments.

[0029] Also, in the drawings, the size, layer thickness, or area may be exaggerated for clarity in some cases. Therefore, it is not necessarily limited to that scale. Note that the drawings are schematically showing ideal examples and are not limited to the shapes or values shown in the drawings.

[0030] Also, the ordinal numbers "first", "second", "third", etc. used in this specification are for the components It is noted that this is for the purpose of avoiding confusion and is not numerically limiting.

[0031] In addition, in this specification, terms indicating arrangements such as "above" and "below" are used for convenience in explaining the positional relationship between components with reference to the drawings. Also, the positional relationship between components changes appropriately according to the direction in which each component is depicted. Therefore, it is not limited to the terms described in the specification and can be appropriately rephrased according to the situation. In addition, in this specification, etc., a transistor is an element having at least three terminals including a gate, a drain, and a source. And there is a channel region between the drain (drain terminal, drain region, or drain electrode) and the source (source terminal, source region, or source electrode), and current can flow through the drain, the channel region, and the source. Note that in this specification, etc., the channel region refers to the region through which current mainly flows. The functions of the source and drain may be interchanged when transistors of different polarities are adopted or when the direction of current changes in the circuit operation. For this reason, in this specification, etc., the terms source and drain can be used interchangeably. In addition, in this specification, etc., "electrically connected" includes the case of being connected through "something having some electrical action". Here, "something having some electrical action" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets.

[0032] In addition, in this specification, etc., a transistor is an element having at least three terminals including a gate, a drain, and a source. And there is a channel region between the drain (drain terminal, drain region, or drain electrode) and the source (source terminal, source region, or source electrode), and current can flow through the drain, the channel region, and the source. Note that in this specification, etc., the channel region refers to the region through which current mainly flows. The functions of the source and drain may be interchanged when transistors of different polarities are adopted or when the direction of current changes in the circuit operation. For this reason, in this specification, etc., the terms source and drain can be used interchangeably. In addition, in this specification, etc., "electrically connected" includes the case of being connected through "something having some electrical action". Here, "something having some electrical action" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets. It is noted that this is for the purpose of avoiding confusion and is not numerically limiting. In addition, in this specification, etc., a transistor is an element having at least three terminals including a gate, a drain, and a source. And there is a channel region between the drain (drain terminal, drain region, or drain electrode) and the source (source terminal, source region, or source electrode), and current can flow through the drain, the channel region, and the source. Note that in this specification, etc., the channel region refers to the region through which current mainly flows. The functions of the source and drain may be interchanged when transistors of different polarities are adopted or when the direction of current changes in the circuit operation. For this reason, in this specification, etc., the terms source and drain can be used interchangeably.

[0033] In addition, in this specification, etc., "electrically connected" includes the case of being connected through "something having some electrical action". Here, "something having some electrical action" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets. The functions of the source and drain may be interchanged when transistors of different polarities are adopted or when the direction of current changes in the circuit operation. For this reason, in this specification, etc., the terms source and drain can be used interchangeably. In addition, in this specification, etc., "electrically connected" includes the case of being connected through "something having some electrical action". Here, "something having some electrical action" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets. It is noted that this is for the purpose of avoiding confusion and is not numerically limiting.

[0034] In addition, in this specification, etc., "electrically connected" includes the case of being connected through "something having some electrical action". Here, "something having some electrical action" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets. Here, "something having some electrical action" is not particularly limited as long as it enables the exchange of electrical signals between the connection targets. It is noted that this is for the purpose of avoiding confusion and is not numerically limiting. . For example, "something having some electrical effect" includes electrodes, wiring, switching elements such as transistors, resistance elements, inductors, capacitors, and other elements having various functions.

[0035] Also, in this specification and the like, "parallel" means a state in which two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, the case of -5° or more and 5° or less is also included. Also, "perpendicular" means a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, the case of 85° or more and 95° or less is also included.

[0036] Also, in this specification and the like, the term "film" and the term "layer" can be interchanged with each other. For example, the term "conductive layer" may be changed to the term "conductive film". Or, for example, the term "insulating film" may be changed to the term "insulating layer".

[0037] Also, in this specification and the like, unless otherwise specified, the off-current refers to the drain current when the transistor is in the off state (also referred to as the non-conducting state or the cut-off state). The off state, unless otherwise specified, for an n-channel type transistor, is a state where the voltage Vgs between the gate and the source is lower than the threshold voltage Vth, and for a p-channel type transistor, is a state where the voltage Vgs between the gate and the source is higher than the threshold voltage Vth. For example, the off-current of an n-channel type transistor may refer to the drain current when the voltage Vgs between the gate and the source is lower than the threshold voltage Vth.

[0038] ​​​​​​​​​​​​​The off-state current of a transistor may depend on Vgs. The off-state current is I or less if there is a Vgs value at which the off-state current of the transistor is I or less. The off-state current of a transistor is the current that flows through it in the off state at a given Vgs. , an off-state at Vgs within a predetermined range or a sufficiently reduced off-current is obtained. It may refer to the off-state current at Vgs.

[0039] As an example, when the threshold voltage Vth is 0.5V and Vgs is 0.5V, The on-current is 1×10 -9 A, and the drain current at Vgs of 0.1 V is 1×10 -1 3 A, and the drain current at Vgs = -0.5 V is 1 × 10 -19 A and Vg The drain current at s = -0.8V is 1×10 -22 A n-channel transistor The drain current of the transistor is as follows when Vgs is -0.5V: , or 1×10 when Vgs is in the range of -0.5V to -0.8V -19 A or below Therefore, the off-state current of the transistor is 1×10 -19 It may be said that it is below A. The drain current of the transistor is 1×10 -22 A or less Vgs exists. Therefore, the off-state current of the transistor is 1×10 -22 It may be said that it is below A.

[0040] In this specification and the like, the off-state current of a transistor having a channel width W is calculated based on the It is sometimes expressed as the current value that flows per watt. It may be represented by the current value flowing through the drain. In the latter case, the unit of the off-current may be represented by a unit having the dimension of current / length (for example, A / μm).

[0041] The off-current of a transistor may depend on temperature. In this specification, unless otherwise specified, the off-current may represent the off-current at room temperature, 60°C, 85°C, 95°C, or 125°C. Or, it may represent the off-current at the temperature at which the reliability of the semiconductor device including the transistor is guaranteed, or the temperature at which the semiconductor device including the transistor is used (for example, any one of the temperatures from 5°C to 35°C). That the off-current of a transistor is I or less means that there exists a value of Vgs such that the off-current of the transistor at room temperature, 60°C, 85°C, 95°C, 125°C, the temperature at which the reliability of the semiconductor device including the transistor is guaranteed, or the temperature at which the semiconductor device including the transistor is used (for example, any one of the temperatures from 5°C to 35°C) is I or less.

[0042] The off-current of a transistor may depend on the voltage Vds between the drain and the source. In this specification, unless otherwise specified, the off-current may represent the off-current at Vds = 0.1V, 0.8V, 1V, 1.2V, 1.8V, 2.5V, 3V, 3.3V, 10V, 12V, 16V, or 20V. Or, it may represent the off-current at Vds at which the reliability of the semiconductor device including the transistor is guaranteed, or the off-current at Vds used in the semiconductor device including the transistor. That the off-current of a transistor is I or less means that Vds is 0.1V, 0.8V, 1V, 1.2V, 1.8V, ​​​​​​​​​​​​​​​​ 2.5V, 3V, 3.3V, 10V, 12V, 16V, 20V, when the transistor is included in the semiconductor device, the Vds at which the reliability of the semiconductor device is guaranteed, or the Vds used in the semiconductor device or the like including the transistor, there may be a case where the value of Vgs is such that the off-current of the transistor becomes I or less.

[0043] In the description of the off-current above, the drain may be read as the source. That is, the off-current may refer to the current flowing through the source when the transistor is in the off state.

[0044] Also, in this specification and the like, in the same meaning as the off-current, it may be described as the leakage current. Also, in this specification and the like, the off-current refers to, for example, when the transistor is in the off state the current flowing between the source and the drain.

[0045] Also, in this specification and the like, the threshold voltage of the transistor refers to the gate voltage (Vg) when a channel is formed in the transistor. Specifically, the threshold voltage of the transistor refers to the gate voltage (Vg) on the horizontal axis and the square root of the drain current (Id) on the vertical axis in the plotted curve (Vg-√Id characteristic), the gate voltage (Vg) at the intersection of the straight line obtained by extrapolating the tangent line with the maximum slope and the square root of the drain current (Id) being 0 (Id being 0 A). Alternatively, the threshold voltage of the transistor refers to the gate voltage (Vg) when the channel length is L, the channel width is W, and the value of Id[A]×L[μm] / W[μm] becomes 1×10 [A]. -9

[0046] ​​​​​​​​Also, in this specification and the like, even when the term "semiconductor" is used, for example, if the conductivity is sufficiently low, it may have the characteristics of an "insulator". Also, the boundary between "semiconductor" and " insulator" is ambiguous and may not be strictly distinguishable. Therefore, the "semiconductor" described in this specification and the like may be convertible to "insulator". Similarly, the "insulator" described in this specification and the like may be convertible to "semiconductor". Also the "insulator" described in this specification and the like may be convertible to "semi-insulator" .

[0047] Also, in this specification and the like, even when the term "semiconductor" is used, for example, if the conductivity is sufficiently high, it may have the characteristics of a "conductor". Also, the boundary between "semiconductor" and " conductor" is ambiguous and may not be strictly distinguishable. Therefore, the "semiconductor" described in this specification and the like may be convertible to "conductor". Similarly, the "conductor" described in this specification and the like may be convertible to "semiconductor".

[0048] Also, in this specification and the like, the impurities in a semiconductor refer to those other than the main components constituting the semiconductor film. For example, an element with a concentration of less than 0.1 atomic% is an impurity. The inclusion of impurities may cause the formation of DOS (Density of States) in the semiconductor, a decrease in carrier mobility, a decrease in crystallinity, etc. When the semiconductor has an oxide semiconductor, examples of the impurities that change the characteristics of the semiconductor include, for example, Group 1 elements, Group 2 elements, Group 14 elements, Group 15 elements, and include hydrogen (also contained in water), lithium, sodium, silicon, boron, phosphorus, carbon, nitrogen, etc. In the case of an oxide semiconductor, for example, oxygen vacancies may be formed due to the incorporation of impurities such as hydrogen. Further, when the semiconductor has silicon, impurities that change the characteristics of the semiconductor include, for example, Group 1 elements, Group 2 elements, Group 13 elements, excluding oxygen and hydrogen, and Group 15 elements.

[0049] (Embodiment 1) In this embodiment, a semiconductor device and a method for manufacturing a semiconductor device according to an aspect of the present invention will be described with reference to FIGS. 1 to 17.

[0050] <1-1. Configuration Example 1 of Semiconductor Device> FIG. 1(A) is a top view of a semiconductor device 100 according to an aspect of the present invention, and FIG. 1(B) corresponds to a cross-sectional view of a cut surface between the dashed-dotted line A1 - A2 shown in FIG. 1(A). Note that FIG. 1( B) includes a cross-section in the channel length (L) direction of the transistor Tr1 and a cross-section in the channel length (L) direction of the transistor Tr2.

[0051] Also, in FIG. 1(A), in order to avoid complexity, some of the components of the semiconductor device 100 (such as the insulating film that functions as a gate insulating film) and some of the reference numerals of the components are omitted and shown. Note that in the top view of the semiconductor device, as in FIG. 1(A ) in the following drawings, some of the components and some of the reference numerals of the components may be omitted and shown.

[0052] The semiconductor device 100 shown in FIGS. 1(A) and 1(B) has a transistor Tr1 and a transistor Tr2 at least partially overlapping with the transistor T r1. Note that the transist Both the switch Tr1 and the transistor Tr2 are transistors with a bottom gate structure. .

[0053] By providing a region where at least a part of the transistor Tr1 and the transistor Tr2 overlap each other, the layout area of the transistors can be reduced.

[0054] The transistor Tr1 includes a conductive film 104 on the substrate 102, an insulating film 106 on the substrate 102 and the conductive film 104, an oxide semiconductor film 108 on the insulating film 106, a conductive film 112a on the oxide semiconductor film 108, a conductive film 112b on the oxide semiconductor film 108, an insulating film 114 on the oxide semiconductor film 108, the conductive film 112a, and the conductive film 112b, an insulating film 116 on the insulating film 114, and a conductive film 122c on the insulating film 116.

[0055] Also, the transistor Tr2 includes a conductive film 112b, an insulating film 114 on the conductive film 112b, an insulating film 116 on the insulating film 114, an oxide semiconductor film 128 on the insulating film 116, a conductive film 122a on the oxide semiconductor film 128, a conductive film 122b on the oxide semiconductor film 128, an insulating film 124 on the oxide semiconductor film 128, the conductive film 122a, and the conductive film 122b, an insulating film 126 on the insulating film 124, and a conductive film 130 on the insulating film 126. Note that the conductive film 130 is connected to the conductive film 122a through an opening 182 provided in the insulating films 124 and 126.

[0056] As shown in FIGS. 1(A) and 1(B), the oxide semiconductor film 108 and the oxide semiconductor film 128 have an overlapping region. As shown in FIGS. 1(A) and 1(B), the channel region formed in the oxide semiconductor film 108 of the transistor Tr1 and the oxide of the transistor Tr2 It is preferable that the channel regions formed in the oxide semiconductor films 128 do not overlap with each other.

[0057] When the channel region of the transistor Tr1 and the channel region of the transistor Tr2 overlap each other, it may affect the other when one of the transistors is operating. To avoid this influence, a configuration in which the interval between the transistor Tr1 and the transistor Tr2 is increased, or a configuration in which a conductive film is provided between the transistor Tr1 and the transistor Tr2, etc. may be mentioned. However, in the case of the former configuration, since the semiconductor device becomes thick, for example, when the semiconductor device 100 is formed on a flexible substrate or the like, bendability and the like may become a problem. Also, in the case of the latter configuration, an increase in the process of forming the conductive film and a problem may occur because the semiconductor device becomes thick as in the case of the former configuration. In the semiconductor device 100 according to one aspect of the present invention, on the other hand, the transistor Tr1 and the transistor Tr2 are arranged so as to overlap each other, and the channel regions of the respective transistors are provided without overlapping. Further, by arranging a part of the oxide semiconductor film in which the channel region is formed so as to overlap, the arrangement area of the transistor can be suitably reduced. Also, the oxide semiconductor film 108 and the oxide semiconductor film 128 each contain In, M (M is Al, Ga, Y, or Sn), and Zn. For example, as the oxide semiconductor film 108 and the oxide semiconductor film 128, it is preferable that each has a region where the atomic ratio of In is larger than the atomic ratio of M. However, the semiconductor device according to one aspect of the present invention is not limited to this.

[0058]

[0059] ​​​​​​​​A structure having a region where the atomic ratio of In is less than the atomic ratio of M, or the atomic ratio of In may also be a structure having a region where it is the same as the atomic ratio of M.

[0060] Further, the oxide semiconductor film 108 and the oxide semiconductor film 128 preferably have the same composition or a substantially the same composition. By making the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 the same, it becomes possible to reduce the manufacturing cost. However, the semiconductor device according to one aspect of the present invention is not limited to this, and the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 may be different. By making the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 the same, it becomes possible to reduce the manufacturing cost. However, the semiconductor device according to one aspect of the present invention is not limited to this, and the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 may be different. By making the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 the same, it becomes possible to reduce the manufacturing cost. However, the semiconductor device according to one aspect of the present invention is not limited to this, and the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 may be different. of the present invention is not limited to this, and the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 may be different. of the present invention is not limited to this, and the compositions of the oxide semiconductor film 108 and the oxide semiconductor film 128 may be different.

[0061] Since the oxide semiconductor film 108 and the oxide semiconductor film 128 have a region where the atomic ratio of In is larger than the atomic ratio of M, the field-effect mobilities of the transistor Tr1 and the transistor Tr2 can be increased. Specifically, the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 exceeds 10 cm / Vs, and more preferably the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 exceeds 30 cm / Vs. 2 / Vs, and more preferably the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 exceeds 30 cm / Vs. 2 / Vs.

[0062] For example, by using the transistor with the above high field-effect mobility in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow frame) can be provided. Further, by using the transistor with the above high field-effect mobility in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, it is possible to connect to the display device. For example, by using the transistor with the above high field-effect mobility in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow frame) can be provided. Further, by using the transistor with the above high field-effect mobility in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, it is possible to connect to the display device. For example, by using the transistor with the above high field-effect mobility in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow frame) can be provided. Further, by using the transistor with the above high field-effect mobility in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, it is possible to connect to the display device. For example, by using the transistor with the above high field-effect mobility in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow frame) can be provided. Further, by using the transistor with the above high field-effect mobility in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, it is possible to connect to the display device. For example, by using the transistor with the above high field-effect mobility in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow frame) can be provided. Further, by using the transistor with the above high field-effect mobility in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, it is possible to connect to the display device. It is possible to provide a display device with a small number of continuous wirings. Also, by using a transistor having a high field-effect mobility as either one or both of the selection transistor and the driving transistor of the pixel circuit of the display device, it is possible to provide a display device with high display quality. is used for either one or both of the selection transistor and the driving transistor of the pixel circuit of the display device, a display device with high display quality can be provided. is used for either one or both of the selection transistor and the driving transistor of the pixel circuit of the display device, a display device with high display quality can be provided. is possible.

[0063] Further, the semiconductor device 100 shown in FIGS. 1(A) and 1(B) can be suitably used for the pixel circuit of the display device, and by arranging it as shown in FIGS. 1(A) and 1(B), the pixel density of the display device can be increased. For example, even when the pixel density of the display device exceeds 1000 ppi (pixels per inch), or when the pixel density of the display device exceeds 2000 ppi, by arranging it as shown in FIGS. 1(A) and 1(B), the aperture ratio of the pixel can be increased. Note that ppi is a unit representing the number of pixels per inch. is possible. high. For example, when the pixel density of the display device exceeds 1000 ppi (pixels per inch), or when the pixel density of the display device exceeds 2000 ppi In this case, by arranging it as shown in FIGS. 1(A) and 1(B), the aperture ratio of the pixel can be increased. Note that ppi is a unit representing the number of pixels per inch.

[0064] <1-2. Pixel Circuit of Display Device> Here, an example of the case where the semiconductor device 100 shown in FIGS. 1(A) and 1(B) is applied to the pixel circuit of the display device will be described with reference to FIG. 2. will be described with reference to FIG. 2.

[0065] FIG. 2 is a circuit diagram showing an example of the case where the semiconductor device 100 is applied to the pixel circuit of the display device. is a circuit diagram.

[0066] The semiconductor device 100 shown in FIG. 2 includes a transistor Tr1, a transistor Tr2, a capacitor element Cs1, and a light-emitting element 160. In FIG. 2, a configuration in which two semiconductor devices 100 are adjacent to each other in the column direction is illustrated. The semiconductor device 100 functions as one of the pixels (or also referred to as sub-pixels). Also, for the capacitor element Cs1, although not shown in FIG. 1 has a transistor Tr1, a transistor Tr2, a capacitor element Cs1, and a light-emitting element 160. In FIG. 2, a configuration in which two semiconductor devices 100 are adjacent to each other in the column direction is illustrated. The semiconductor device 100 functions as one of the pixels (or also referred to as sub-pixels). Also, for the capacitor element Cs1, although not shown in FIG. 1 is also referred to) and functions as one of the pixels. Also, for the capacitor element Cs1, although not shown in FIG. 1 However, for example, it can be formed using the parasitic capacitance between the conductive film 112b of the transistor Tr1 and the conductive film 122b of the transistor Tr 2.

[0067] Also, in the circuit diagram shown in FIG. 2, a data line DL _Y-1 for writing a data signal to a pixel, a data line DL_Y for writing a data signal to an adjacent pixel, and a light-emitting element An anode line ANODE_X-1 for supplying a potential to the anode line ANODE_X for supplying a potential to an adjacent light-emitting element, and a scan line GL_X for supplying a scan signal to the pixel are shown. Yes. Yes.

[0068] One of the source electrode and the drain electrode of the transistor Tr1 is electrically connected to the data line DL_Y-1. Furthermore, the first gate electrode and the second gate The electrode is electrically connected to the scan line GL_X. The transistor Tr1 has a function of controlling the writing of data of the data signal by being turned on or Turned off.

[0069] One of the pair of electrodes of the capacitor element Cs1 is electrically connected to the other of the source electrode and the drain Electrode of the electrode. Also, the other of the pair of electrodes of the capacitor element Cs1 is the transistor Tr It is electrically connected to the second gate electrode (also referred to as a back gate electrode) of 2. The capacitor element Cs1 has a function as a holding capacitor for holding the written data.

[0070] One of the source electrode and the drain electrode of the transistor Tr2 is electrically connected to the anode line ANODE_ X-1.

[0071] One of the pair of electrodes of the light-emitting element 160 is the source electrode and the drain of the transistor Tr2 is electrically connected to the other electrode, and the other is electrically connected to the cathode line CATHODE Note that one of the pair of electrodes of the light-emitting element 160 is electrically connected to the other of the pair of electrodes of the capacitor element Cs1 is electrically connected.

[0072] The above configuration is an example of an application of the semiconductor device 100 shown in FIGS. 1(A) and 1(B) to a pixel of a display device is an example.

[0073] <1-3. Configuration of Semiconductor Device> Again, the semiconductor device 100 shown in FIGS. 1(A) and 1(B) will be described. When the semiconductor device 100 shown in FIGS. 1(A) and 1(B) is applied to a pixel of a display device, for example, the channel length (L) and channel width (W) of the transistor, or the line width of the wiring and electrodes connected to the transistor can be made relatively large. For example, compared with the case where the transistor Tr1 and the transistor Tr2 are arranged on the same plane, as shown in FIGS. 1(A) and 1(B), by arranging at least a part of the transistor Tr1 and the transistor Tr2 overlapping each other, the line width and the like can be made large, so that variations in processing dimensions can be reduced. can be made large, so that variations in processing dimensions can be reduced. can be made large, so that variations in processing dimensions can be reduced.

[0074] In addition, either one or both of the conductive film and the insulating film can be commonly used for the transistor Tr1 and the transistor Tr2, so that the number of masks or the number of processes can be reduced is possible. is possible.

[0075] For example, in the transistor Tr1, the conductive film 104 functions as the first gate electrode the conductive film 112a functions as the source electrode, the conductive film 112b functions as the drain electrode functions, and the conductive film 122c functions as the second gate electrode. Also, in the transistor Tr1 Here, the insulating film 106 functions as the first gate insulating film, and the insulating films 114 and 116 function as the second gate insulating film. Also, in the transistor Tr2, the conductive film 112b functions as the first gate electrode, the conductive film 122a functions as the source electrode, the conductive film 122 b functions as the drain electrode, and the conductive film 130 functions as the second gate electrode. Also , in the transistor Tr2, the insulating films 114 and 116 function as the first gate insulating film and the insulating films 124 and 126 function as the second gate insulating film.

[0076] Note that in this specification and the like, the insulating film 106 may be referred to as the first insulating film, the insulating films 114 and 116 as the second insulating film, and the insulating films 124 and 126 as the third insulating film, respectively. .

[0077] Also, an insulating film 134 and an insulating film 136 on the insulating film 134 are provided on the conductive film 130 . Also, an opening 184 reaching the conductive film 130 is provided in the insulating films 134 and 136. Also, a conductive film 138 is provided on the insulating film 136. Note that the conductive film 138 is connected to the conductive film 130 through the opening 184.

[0078] Also, an insulating film 140, an EL layer 142, and a conductive film 144 are provided on the conductive film 138 . The insulating film 140 covers a part of the side end portion of the conductive film 138 and has a function of preventing a short circuit of the conductive film 138 between adjacent pixels. Also, the EL layer 142 has a function of emitting light . Also, the light emitting element 160 is formed by the conductive film 138, the EL layer 142, and the conductive film 144. The conductive film 138 functions as one electrode of the light emitting element 160, and the conductive film 144 functions as the other electrode of the light emitting element 160.

[0079] As described above, the semiconductor device according to one aspect of the present invention has a stacked structure of a plurality of transistors, reducing the installation area of the transistors. Further, in the plurality of transistors, by commonly using either one or both of the insulating film and the conductive film, the number of masks or the number of processes can be reduced. can be reduced.

[0080] <1-4. Configuration of Gate Electrode> Also, as shown in FIGS. 1(A) and 1(B), the transistors Tr1 and Tr2 each have a configuration having two gate electrodes.

[0081] Here, the effect of the configuration having two gate electrodes will be described with reference to FIGS. 1(A) and 1(B) and FIG. 3. using.

[0082] Note that FIG. 3 corresponds to a cross-sectional view of a cut surface between the dashed-dotted line B1 - B2 shown in FIG. 1(A). Also, FIG. 3 includes a cross-section in the channel width (W) direction of the transistor Tr1.

[0083] As shown in FIG. 3, the conductive film 122c functioning as the second gate electrode is electrically connected to the conductive film 104 functioning as the first gate electrode through the opening 181. Therefore, the same potential is applied to the conductive film 104 and the conductive film 122c. Also, as shown in FIG. 3, the oxide semiconductor film 108 is positioned to face the conductive film 104 and the conductive film 122c, and is sandwiched between the conductive films functioning as two gate electrodes. The lengths of the conductive film 104 and the conductive film 122 c in the channel width direction are each longer than the length of the oxide semiconductor film 108 in the channel width direction, and the entire oxide semiconductor film 108 is covered by the conductive film 104 and the conductive film 122 c via the insulating films 106, 114, and 116. is covered by the film 104 and the conductive film 122c.

[0084] In other words, the conductive film 104 and the conductive film 122c are connected at the opening 181 formed in the insulating films 106, 114, and 116, and have a region located outside the side end portion of the oxide semiconductor film 108.

[0085] With such a configuration, the oxide semiconductor film 108 included in the transistor Tr1 can be electrically surrounded by the electric fields of the conductive film 104 and the conductive film 122c. A device structure of a transistor in which an oxide semiconductor film in which a channel region is formed by the electric fields of a first gate electrode and a second gate electrode, such as the transistor Tr1, is electrically surrounded can be called a Surrounded channel (S-channel) structure.

[0086] Since the transistor Tr1 has an S-channel structure, an electric field for inducing a channel can be effectively applied to the oxide semiconductor film 108 by the conductive film 104 that functions as the first gate electrode. Therefore, the current driving ability of the transistor Tr1 is improved, and high on-current characteristics can be obtained. In addition, since it is possible to increase the on-current, the transistor Tr1 can be miniaturized. Further, since the transistor Tr1 has a structure surrounded by the conductive film 104 that functions as the first gate electrode and the conductive film 122c that functions as the second gate electrode, the mechanical strength can be increased.

[0087] In the above description, a configuration in which the first gate electrode and the second gate electrode are connected is exemplified, but the present invention is not limited to this. For example, the transistor T shown in FIG. 1(B). The conductive film 130 that functions as the second gate electrode, such as r2, is electrically connected to the conductive film 122a that functions as the source electrode or the drain electrode of the transistor Tr2. This configuration may be adopted.

[0088] <1-5. Components of the semiconductor device> Next, the components included in the semiconductor device of the present embodiment will be described in detail.

[0089] [Substrate] There are no major restrictions on the material of the substrate 102, etc., but it is necessary to have at least heat resistance enough to withstand subsequent heat treatment. For example, a glass substrate, a ceramic substrate, a quartz substrate, a sapphire substrate, etc. may be used as the substrate 102. Also, a single crystal semiconductor substrate, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, an SOI substrate, etc. made of silicon or silicon carbide can be applied, and those with semiconductor elements provided on these substrates may be used as the substrate 102. When using a glass substrate as the substrate 102, a large-sized display device can be manufactured by using a large-area substrate such as the 6th generation (1500 mm × 1850 mm), the 7th generation (1870 mm × 2200 mm), the 8th generation (2200 mm × 2400 mm), the 9th generation (2400 mm × 2800 mm), the 10th generation (2950 mm × 3400 mm), etc.

[0090] Also, a flexible substrate may be used as the substrate 102, and the semiconductor device 100 may be formed directly on the flexible substrate. Or, a release layer may be provided between the substrate 102 and the semiconductor device 100. The release layer is separated from the substrate 102 after partially or completely completing the semiconductor device thereon. Moreover, it can be used for transfer onto other substrates. In this case, the semiconductor device 100 can be transferred onto substrates with poor heat resistance or flexible substrates.

[0091] [Conductive film] As the conductive film 104, conductive film 112a, conductive film 112b, conductive film 122a, conductive film 122b, conductive film 122c, conductive film 130, conductive film 138, and conductive film 144, chromium (C r), copper (Cu), aluminum (Al), gold (Au), silver (Ag), zinc (Zn), mol ybdenum (Mo), tantalum (Ta), titanium (Ti), tungsten (W), manganese (Mn), nickel (Ni), iron (Fe), cobalt (Co), a metal element selected therefrom, or an alloy containing the above-described metal element as a component, or an alloy combining the above-described metal elements, etc. can be used to form each of them.

[0092] In addition, for the conductive film 104, conductive film 112a, conductive film 112b, conductive film 122a, conductive film 12 2b, conductive film 122c, conductive film 130, conductive film 138, and conductive film 144, oxides containing indium and tin, oxides containing tungsten and indium, oxides containing tungsten, indium, and zinc, oxides containing titanium and indium, oxides containing titanium, indium, and tin, oxides containing indium and zinc, oxides containing silicon, indium, and tin, oxides containing indium, gallium, and zinc, etc., i.e., oxide conductors can also be applied. In particular, for the conductive film 130, the above-described oxide conductor can be preferably used. Here, an explanation will be given of the oxide conductor. In this specification, etc., the oxide conductor is referred to as OC (Oxid

[0093] ​​It may also be referred to as an "e Conductor". As the oxide conductor, for example, when oxygen deficiency is formed in an oxide semiconductor and hydrogen is added to the oxygen deficiency, donor levels are formed near the conduction band. As a result, the oxide semiconductor becomes highly conductive and turns into a conductor. The oxide semiconductor that has become conductive can be called an oxide conductor. Generally, since an oxide semiconductor has a large energy gap, it has translucency to visible light. On the other hand, an oxide conductor is an oxide semiconductor having donor levels near the conduction band. Therefore, the influence of absorption by the donor levels on the oxide conductor is small, and it has translucency to visible light comparable to that of the oxide semiconductor.

[0094] Also, for the conductive film 104, the conductive film 112a, the conductive film 112b, the conductive film 122a, the conductive film 12 2b, the conductive film 122c, the conductive film 130, the conductive film 138, and the conductive film 144, a Cu-X alloy film (X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti) may be applied. By using a Cu-X alloy film, it can be processed in a wet etching process, so it becomes possible to suppress the manufacturing cost.

[0095] In particular, for any one or more of the conductive film 104, the conductive film 112a, the conductive film 112b, the conductive film 122a, the conductive film 12 2b, and the conductive film 122c, the above-mentioned Cu-X alloy film can be preferably used. As the Cu-X alloy film, a Cu-Mn alloy film is particularly preferable.

[0096] Also, for any one or more of the conductive film 104, the conductive film 112a, the conductive film 112b, the conductive film 122a, the conductive film 12 2b, and the conductive film 122c, among the above-mentioned metal elements, in particular ​​​​​​​It is preferable to have any one or more selected from aluminum, copper, titanium, tungsten, tantalum, and molybdenum. It is preferably used.

[0097] In addition, for any one or more of the conductive film 104, the conductive film 112a, the conductive film 112b, the conductive film 122a, the conductive film 12 2b, and the conductive film 122c, it is preferable to use a so-called tantalum nitride film containing nitrogen and tantalum. The tantalum nitride film has conductivity and has a high barrier property against copper or hydrogen. In addition, since the tantalum nitride film releases less hydrogen from itself, it can be most preferably used as a metal film in contact with the oxide semiconductor film 108 or a metal film in the vicinity of the oxide semiconductor film 108.

[0098] [Insulating film] As the insulating film 106, the insulating film 114, the insulating film 116, the insulating film 124, the insulating film 126, the insulating film 1 34, the insulating film 136, and the insulating film 140, an insulating layer containing one or more of a silicon oxide film, a silicon oxynitride film , a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film can be used respectively.

[0099] In addition, the insulating film 106 has a function as a blocking film that suppresses oxygen permeation. For example, when any one or more of the insulating film 114, the insulating film 116, the oxide semiconductor film 108, the oxide semiconductor film 128, the insulating film 124, and the insulating film 126 have an excess oxygen region oxygen permeation can be suppressed by the insulating film 106.

[0100] Note that when the oxide semiconductor film 108 or the oxide semiconductor film 128 is in contact with the The insulating film to be used is preferably an oxide insulating film, and the composition of the insulating film is preferably in excess of the stoichiometric composition. It is more preferable to have a region containing oxygen (excess oxygen region). The oxide insulating film having an oxygen region is an insulating film that can release oxygen.

[0101] Note that the oxide insulating film having the above-described excess oxygen region can be formed by, for example, Forming an insulating film, heat-treating the formed insulating film in an oxygen atmosphere, or The method of adding oxygen to the insulating film after the film formation is also Plasma treatment is preferred.

[0102] Also, an insulating film that functions as a gate insulating film for the transistor Tr1 and the transistor Tr2 The insulating film that functions as a gate insulating film may be made of hafnium oxide. When nium is used, the following effects are achieved.

[0103] Hafnium oxide has a higher dielectric constant than silicon oxide and silicon oxynitride. Therefore, compared to when silicon oxide is used, the thickness of the insulating film can be made larger, and therefore the tunnel This reduces the leakage current due to the current flowing through the transistor. Furthermore, hafnium oxide, which has a crystalline structure, can be used to form amorphous structures. Therefore, the off-state current is small. To form a transistor, it is preferable to use hafnium oxide having a crystalline structure. Examples of the crystal structure include monoclinic and cubic crystals. The types are not limited to these.

[0104] Also, an insulating film that functions as a gate insulating film for the transistor Tr1 and the transistor Tr2 The insulating film that functions as a gate insulating film may be made of silicon nitride. When silicon nitride is used, the following effects are achieved: Silicon nitride has a low dielectric constant compared to silicon oxide. The required thickness to obtain the same capacitance as silicon oxide is large, so an insulating film is Therefore, the dielectric strength of the transistors Tr1 and Tr2 can be increased. By suppressing the voltage drop and improving the dielectric strength, the transistor Tr1 and the transistor This can suppress electrostatic breakdown of Tr2.

[0105] The insulating films 114, 116, 124, and 126 are formed of the oxide semiconductor film 108 or the oxide It has a function of supplying oxygen to one or both of the semiconductor films 128. The insulating films 114, 116, 124, and 126 contain oxygen. The insulating film 114 is an insulating film that can transmit oxygen. The insulating layer 116 also functions as a layer for reducing damage to the oxide semiconductor layer 108 when the insulating layer 116 is formed. The insulating film 124 prevents damage to the oxide semiconductor film 128 when the insulating film 126 is formed later. It also functions as an image-reducing membrane.

[0106] The insulating films 114 and 124 have a thickness of 5 nm to 150 nm, preferably 5 nm. Silicon oxide, silicon oxynitride, etc. having a thickness of 50 nm or more can be used.

[0107] Furthermore, it is preferable that the insulating films 114 and 124 have a small number of defects. By measurement, the signal strength that appears at g = 2.001, which is derived from the dangling bonds of silicon, is The pin density is preferably 3×10 17 spins / cm 3 or less. This is because if the defect density in the insulating films 114 and 124 is high, oxygen will bind to the defects, resulting in a decrease in the oxygen permeation rate in the insulating film 11 4.

[0108] In addition, the insulating films 114 and 124 can be formed using an oxide insulating film with a low level density caused by nitrogen oxides. The level density caused by the nitrogen oxides may be formed between the energy (Ev_os) at the upper end of the valence band of the oxide semiconductor film and the energy (Ec_os) at the lower end of the conduction band of the oxide semiconductor film. As the oxide insulating film, a silicon oxynitride film with a low nitrogen oxide emission amount or an aluminum oxynitride film with a low nitrogen oxide emission amount can be used. Note that the level density caused by the nitrogen oxides The energy at the upper end of the valence band of the oxide semiconductor film (Ev_os) and the energy at the lower end of the conduction band of the oxide semiconductor film (Ec_os) It may be formed between them. As the above oxide insulating film, a silicon oxynitride film with a small nitrogen oxide emission amount or an aluminum oxynitride film with a small nitrogen oxide emission amount etc. can be used.

[0109] Note that a silicon oxynitride film with a small nitrogen oxide emission amount is a film in which the ammonia emission amount is larger than the nitrogen oxide emission amount in the temperature-programmed desorption gas analysis method (TD S). Typically, The ammonia emission amount is 1×10 18 cm -3 or more and 5×10 19 cm -3 or less. Note that The above ammonia emission amount is the total amount in the range where the temperature of the heat treatment in TDS is 50°C or more and 650°C or less, or 50°C or more and 550°C or less. Also, the above ammonia emission amount is the total amount in terms of ammonia molecules in TDS.

[0110] Nitrogen oxides (NO x , where x is greater than 0 and less than or equal to 2, preferably 1 or more and 2 or less), typically​​​ NO2 or NO forms levels in insulating films 114, 124, etc. The levels are located within the energy gap of oxide semiconductor films 108, 128. Therefore, when nitrogen oxide diffuses to the interface between insulating film 114 and oxide semiconductor film 108 or to the interface between insulating film 124 and oxide semiconductor film 128, the levels may trap electrons on the insulating film 114, 124 side. As a result, the trapped electrons remain near the interface between insulating film 114 and oxide semiconductor film 1 08 or near the interface between insulating film 124 and oxide semiconductor film 128, causing the threshold voltage of the transistor to shift in the positive direction.

[0111] In addition, nitrogen oxide reacts with ammonia and oxygen in the heat treatment. The nitrogen oxide contained in insulating films 114 , 124 reacts with the ammonia contained in insulating films 116, 126 in the heat treatment, so that the nitrogen oxide contained in insulating films 114, 124 is reduced. Therefore, electrons are less likely to be trapped at the interface between insulating film 114 and oxide semiconductor film 108 or at the interface between insulating film 124 and oxide semiconductor film 128.

[0112] By using the above oxide insulating film as insulating films 114, 124, it is possible to reduce the shift of the threshold voltage of the transistor and reduce the variation in the electrical characteristics of the transistor.

[0113] Note that by heat treatment in the manufacturing process of the transistor, typically heat treatment at 300°C or higher and lower than 350°C, insulating films 114, 124 have a first signal with a g value of 2.037 or more and 2.039 or less in the spectrum measured by ESR at 100 K or lower, a g value of 2.00 A second signal of 1 or more and 2.003 or less, and a third signal with a g value of 1.964 or more and 1.966 or less are observed. Note that the split widths of the first and second signals, as well as the split widths of the second and third signals, are about 5 mT in the X-band ESR measurement. In addition, the total spin density of the first signal with a g value of 2.037 or more and 2.039 or less, the second signal with a g value of 2.001 or more and 2.003 or less, and the third signal with a g value of 1.964 or more and 1.9 66 or less is less than 1×10 spins / cm 18 3 and typically less than 1×10 17 spins / cm 17 3 and more than 1×10 18 spins / cm 3 is less than.

[0114] Note that in the ESR spectrum at 100 K or less, the total spin density of the first signal with a g value of 2.037 or more and 2.039 or less, the second signal with a g value of 2.001 or more and 2.003 or less, and the third signal with a g value of 1.964 or more and 1.966 or less corresponds to the total spin density of the signal due to nitrogen oxides (NO x , where x is greater than 0 and less than or equal to 2, preferably 1 or more and 2 or less). Representative examples of nitrogen oxides include nitric oxide, nitrogen dioxide, etc. That is, the smaller the total spin density of the first signal with a g value of 2.037 or more and 2.039 or less, the second signal with a g value of 2.00 1 or more and 2.003 or less, and the third signal with a g value of 1.964 or more and 1.966 or less, the lower the content of nitrogen oxides contained in the oxide insulating film.

[0115] ​​​​​​​Also, the oxide insulating film has a nitrogen concentration measured by SIMS of 6×10 20 atoms / cm 3 or less.

[0116] When the substrate temperature is 220°C or higher and 350°C or lower, and the PEC VD method using silane and dinitrogen monoxide is used to form the oxide insulating film, a dense and hard film can be formed.

[0117] The insulating films 116 and 126 are formed using an oxide insulating film containing more oxygen than oxygen satisfying the stoichiometric composition. The oxide insulating film containing more oxygen than oxygen satisfying the stoichiometric composition releases a part of oxygen by heating. The oxide insulating film containing more oxygen than oxygen satisfying the stoichiometric composition has an oxygen release amount of 1.0×10 19 cm -3 or more, preferably 3 .0×10 20 cm -3 or more. The above oxygen release amount is the total amount in the range where the temperature of the heating treatment in TDS is 50°C or higher and 650°C or lower, or 50°C or higher and 550°C or lower. Also, the above oxygen release amount is the total amount in terms of oxygen molecules in TDS.

[0118] As the insulating films 116 and 126, silicon oxide, silicon oxynitride, etc. with a thickness of 30 nm or more and 500 nm or less, preferably 50 nm or more and 400 nm or less can be used.

[0119] Also, the insulating films 116 and 126 preferably have a small amount of defects. Typically, by ESR measurement, the signal peak density of the signal appearing at g = 2.001 derived from silicon dangling bonds is 1.5×10 spins / cm 18 spins / cm 3Less than, and further 1×10 18 spins / cm 3 It is preferably the following.

[0120] In addition, the insulating film 114 and the insulating film 116, and the insulating film 124 and the insulating film 126 can use insulating films of the same kind of material. Therefore, there are cases where the interfaces between the insulating film 114 and the insulating film 116, and between the insulating film 124 and the insulating film 126 cannot be clearly confirmed. Thus, in this embodiment form, the interfaces between the insulating film 114 and the insulating film 116, and between the insulating film 124 and the insulating film 126 are illustrated by broken lines. Since the insulating film 114 and the insulating film 116, and the insulating film 124 and the insulating film 126 can use insulating films of the same kind of material, there are cases where the interfaces between the insulating film 114 and the insulating film 116, and between the insulating film 124 and the insulating film 126 cannot be clearly confirmed. Therefore, in this embodiment form, the interfaces between the insulating film 114 and the insulating film 116, and between the insulating film 124 and the insulating film 126 are illustrated by broken lines. 124 and the insulating film 126 cannot be clearly confirmed. Therefore, in this embodiment form, the interfaces between the insulating film 114 and the insulating film 116, and between the insulating film 124 and the insulating film 12 form, the interfaces between the insulating film 114 and the insulating film 116, and between the insulating film 124 and the insulating film 12 6 are illustrated by broken lines.

[0121] The insulating film 134 has a function as a protective insulating film for the transistor Tr1 and the transistor Tr2. function.

[0122] The insulating film 134 has either or both of hydrogen and nitrogen. Or, the insulating film 1 34 has nitrogen and silicon. Also, the insulating film 134 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. By providing the insulating film 134, the diffusion of oxygen from the oxide semiconductor film 108 and the oxide semiconductor film 128 to the outside, the diffusion of oxygen contained in the insulating films 114, 116, 124, 126 to the outside, and the entry of hydrogen, water, etc. from the outside into the oxide semiconductor films 108, 128 can be prevented. metal, alkaline earth metal, etc. can be blocked. By providing the insulating film 134, the diffusion of oxygen from the oxide semiconductor film 108 and the oxide semiconductor film 128 to the outside, the diffusion of oxygen contained in the insulating films 114, 116, 124, 126 to the outside, and the entry of hydrogen, water, etc. from the outside into the oxide semiconductor films 108, 128 can be prevented. and the diffusion of oxygen to the outside from the oxide semiconductor film 108 and the oxide semiconductor film 128, and the diffusion of oxygen contained in the insulating films 114, 116, 124, 126 to the outside, and the entry of hydrogen, water, etc. from the outside into the oxide semiconductor films 108, 128 can be prevented. oxide semiconductor films 108, 128 can be prevented. semiconductor films 108, 128 can be prevented.

[0123] [[ID=4|2]]As the insulating film 134, for example, a nitride insulating film can be used. Examples of the nitride insulating film include silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, etc. As the nitride insulating film, there are silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, etc. etc.

[0124] [Oxide semiconductor film] As the oxide semiconductor film 108 and the oxide semiconductor film 128, the materials shown above can be used respectively. It is possible.

[0125] When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In > M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 2:1:3, In:M:Zn = 3:1:2, In:M:Zn = 4:2:4.1, etc. The atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In > M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 2:1:3, In:M:Zn = 3:1:2, In:M:Zn = 4:2:4.1, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In > M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 2:1:3, In:M:Zn = 3:1:2, In:M:Zn = 4:2:4.1, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In > M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 2:1:3, In:M:Zn = 3:1:2, In:M:Zn = 4:2:4.1, etc. The atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide preferably satisfies In > M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 2:1:3, In:M:Zn = 3:1:2, In:M:Zn = 4:2:4.1, etc.

[0126] When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide may also satisfy In ≤ M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Zn = 1:3:6, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide may also satisfy In ≤ M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Zn = 1:3:6, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide may also satisfy In ≤ M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = \alpha:1:1.2, In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Zn = 1:3:6, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide may also satisfy In ≤ M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Zn = 1:3:6, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide may also satisfy In ≤ M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Zn = 1:3:6, etc. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides, the atomic number ratio of the metal elements of the sputtering target used to form the In-M-Zn oxide may also satisfy In ≤ M. Examples of such atomic number ratios of the metal elements of the sputtering target include In:M:Zn = 1:1:1, In:M:Zn = 1:1:1.2, In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Zn = 1:3:6, etc.

[0127] When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides respectively, it is preferable to use a target containing polycrystalline In-M-Zn oxide as the sputtering target. By using a target containing polycrystalline In-M-Zn oxide, it is easier to form the oxide semiconductor film 108 and the oxide semiconductor film 128 having crystallinity. Note that the atomic number ratio of the oxide semiconductor film 108 and the oxide semiconductor film 128 to be formed is respectively the plasma ion of the atomic number ratio of the metal elements contained in the above sputtering target. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides respectively, it is preferable to use a target containing polycrystalline In-M-Zn oxide as the sputtering target. By using a target containing polycrystalline In-M-Zn oxide, it is easier to form the oxide semiconductor film 108 and the oxide semiconductor film 128 having crystallinity. Note that the atomic number ratio of the oxide semiconductor film 108 and the oxide semiconductor film 128 to be formed is respectively the plasma ion of the atomic number ratio of the metal elements contained in the above sputtering target. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides respectively, it is preferable to use a target containing polycrystalline In-M-Zn oxide as the sputtering target. By using a target containing polycrystalline In-M-Zn oxide, it is easier to form the oxide semiconductor film 108 and the oxide semiconductor film 128 having crystallinity. Note that the atomic number ratio of the oxide semiconductor film 108 and the oxide semiconductor film 128 to be formed is respectively the plasma ion of the atomic number ratio of the metal elements contained in the above sputtering target. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides respectively, it is preferable to use a target containing polycrystalline In-M-Zn oxide as the sputtering target. By using a target containing polycrystalline In-M-Zn oxide, it is easier to form the oxide semiconductor film 108 and the oxide semiconductor film 128 having crystallinity. Note that the atomic number ratio of the oxide semiconductor film 108 and the oxide semiconductor film 128 to be formed is respectively the plasma ion of the atomic number ratio of the metal elements contained in the above sputtering target. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides respectively, it is preferable to use a target containing polycrystalline In-M-Zn oxide as the sputtering target. By using a target containing polycrystalline In-M-Zn oxide, it is easier to form the oxide semiconductor film 108 and the oxide semiconductor film 128 having crystallinity. Note that the atomic number ratio of the oxide semiconductor film 108 and the oxide semiconductor film 128 to be formed is respectively the plasma ion of the atomic number ratio of the metal elements contained in the above sputtering target. When the oxide semiconductor film 108 and the oxide semiconductor film 128 are In-M-Zn oxides respectively, it is preferable to use a target containing polycrystalline In-M-Zn oxide as the sputtering target. By using a target containing polycrystalline In-M-Zn oxide, it is easier to form the oxide semiconductor film 108 and the oxide semiconductor film 128 having crystallinity. Note that the atomic number ratio of the oxide semiconductor film 108 and the oxide semiconductor film 128 to be formed is respectively the plasma ion of the atomic number ratio of the metal elements contained in the above sputtering target. It includes fluctuations of 40% in eggplant. For example, the sputtering targets of the oxide semiconductor film 108 and the oxide semiconductor film 128 use an atomic ratio of In:Ga:Zn = 4:2:4.1 In the case, the atomic ratio of the formed oxide semiconductor film 108 and the oxide semiconductor film 128 may be in the vicinity of In: Ga:Zn = 4:2:3.

[0128] In addition, the oxide semiconductor film 108 and the oxide semiconductor film 128 have an energy gap of 2e V or more, preferably 2.5 eV or more, more preferably 3 eV or more. Thus, by using an oxide semiconductor with a wide energy gap, the off-current of the transistor Tr1 and the transistor Tr2 can be reduced.

[0129] In addition, the thicknesses of the oxide semiconductor film 108 and the oxide semiconductor film 128 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 5 0 nm or less.

[0130] In addition, hydrogen contained in the oxide semiconductor film 108 and the oxide semiconductor film 128 reacts with oxygen bonded to metal atoms to form water, and at the same time, oxygen vacancies are formed in the lattice from which oxygen has desorbed (or the part from which oxygen has desorbed). When hydrogen enters the oxygen vacancies, carriers, i.e., electrons, may be generated. Also, a part of the hydrogen may bond with oxygen bonded to metal atoms to generate carriers, i.e., electrons. Therefore, a transistor using an oxide semiconductor film containing hydrogen tends to have normally-on characteristics. For this reason, it is preferable that the oxide semiconductor film 108 and the oxide semiconductor film 128 have hydrogen reduced as much as possible.

[0131] Specifically, in the oxide semiconductor film 108 and the oxide semiconductor film 128, the hydrogen concentration obtained by SIMS analysis is 2×10 20 atoms / cm 3 or less, preferably 5×10 19 atoms / cm 3 or less, more preferably 1×10 19 atoms / cm 3 or less, preferably 5×10 18 atoms / cm 3 or less, preferably 1×10 18 atoms / cm 3 or less, more preferably 5×10 17 atoms / cm 3 or less, even more preferably 1×1 0 16 atoms / cm 3 or less.

[0132] Further, if silicon or carbon, which is one of the Group 14 elements, is contained in the oxide semiconductor film 108 and the oxide semiconductor film 128, the oxygen deficiency increases in the oxide semiconductor film 108 and the oxide semiconductor film 12 8, and the film becomes n-type. Therefore, the silicon concentration obtained by SIMS analysis in the oxide semiconductor film 108 and the oxide semiconductor film 128 is 2 ×10 ×10 18 atoms / cm 3 or less, preferably 2×10 17 atoms / cm 3 or less and Further, the carbon concentration obtained by SIMS analysis in the oxide semiconductor film 108 and the oxide semiconductor film 128 is 2×10 18 atoms / cm 3 or less, preferably 2×10 1 7 atoms / cm 3 or less.

[0133] Also, in the oxide semiconductor film 108 and the oxide semiconductor film 128, by SIMS analysis the concentration of the alkali metal or alkaline earth metal obtained is 1×10 18 atom s / cm 3 or less, preferably 2×10 16 atoms / cm 3 or less. Alkali metals and alkaline earth metals may generate carriers when combined with the oxide semiconductor, and the off-current of the transistor may increase. Therefore, it is preferable to reduce the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor film 108 and the oxide semiconductor film 128.

[0134] Also, the oxide semiconductor film 108 and the oxide semiconductor film 128 may each have a non-single crystal structure. The non-single crystal structure includes, for example, CAAC-OS (C Axis Aligned Crystalline Oxide Semiconductor) described later, a polycrystalline structure , a microcrystalline structure, or an amorphous structure. In the non-single crystal structure, the amorphous structure has the highest density of defect levels, and CAAC-OS has the lowest density of defect levels.

[0135] Note that as the various films such as the conductive film, insulating film, and oxide semiconductor film described above, they can be formed by sputtering method, plasma chemical vapor deposition (PECVD: (Plasma Enhanced Chemical Vapor Deposition)) method, thermal CVD (Chemical Vapor Deposition) method. Note that as the thermal CVD method, MOCVD (Metal Organic Chemical Vapo r Deposition), or ALD (Atomic Layer Depos ition), etc.

[0136] Since the thermal CVD method is a film formation method that does not use plasma, it has the advantage that defects are not caused by plasma damage. formed.

[0137] In the thermal CVD method, the source gas and the oxidizing agent are simultaneously fed into the chamber, and the chamber is under atmospheric pressure or reduced pressure, and the reaction is carried out near or on the substrate to deposit a film on the substrate to form a film.

[0138] Also, in the ALD method, the chamber is under atmospheric pressure or reduced pressure, and the source gas for the reaction is used to form a film.

[0139] Thermal CVD methods such as MOCVD and ALD can form various films such as the conductive film, insulating film, and oxide semiconductor film of the above embodiment. For example, when forming an In-Ga-ZnO film trimethylindium, trimethylgallium, and dimethylzinc are used. The chemical formula of trimethylindium is In(CH3)3. Also, the chemical formula of trimethylgallium is Ga(CH3)3. Also, the chemical formula of dimethylzinc is Zn(C H3)2. Also, it is not limited to these combinations, and triethylgallium (chemical formula Ga(C2H5)3) can be used instead of trimethylgallium and diethylzinc (chemical formula Zn(C2H5)2) can be used instead of dimethylzinc. used.

[0140] For example, when forming a hafnium oxide film by a film forming apparatus using ALD, a solvent A liquid containing a hafnium precursor compound (such as hafnium alkoxide or hafnium amide such as tetrakis(dimethyl amide hafnium (TDMAH))) is vaporized to obtain a source gas, and two types of gases, ozone (O3) as an acid ifying agent, are used. The chemical formula of tetrakis(dimethylamide)hafnium is Hf[N(CH3)2]4. Also, as other material liquids, there are tetrakis(ethylmethylamide)hafnium and the like. For example, when forming an aluminum oxide film by a film forming apparatus using ALD, a liquid containing a solvent and an aluminum precursor compound (such as trimethylaluminum (TMA)) is vaporized to obtain a source gas, and two types of gases, H2O as an oxidizing agent, are used. The chemical formula of trimethylaluminum is Al(CH3)3. Also, as other material liquids, there are tris(dimethylamide)aluminum, triisobutylaluminum, aluminum tris(2 2,6,6-tetramethyl-3,5-heptanedionate), and the like.

[0141] For example, when forming a silicon oxide film by a film forming apparatus using ALD, hexachlorodisilane is adsorbed on the film forming surface, chlorine contained in the adsorbed substance is removed, and radicals of an oxidizing gas (O 2, nitrous oxide) are supplied to react with the adsorbed substance. For example, when forming a tungsten film by a film forming apparatus using ALD, an initial tungsten film is formed using WF6 gas and B2H6 gas, and then a tungsten film is formed using WF6 gas and H2 gas. Instead of B2H6 gas, SiH4 gas may be used.

[0142] For example, when forming a tungsten film by a film forming apparatus using ALD, an initial tungsten film is formed using WF6 gas and B2H6 gas, and then a tungsten film is formed using WF6 gas and H2 gas. Instead of B2H6 gas, SiH4 gas may be used.

[0143] For example, when forming a tungsten film by a film forming apparatus using ALD, an initial tungsten film is formed using WF6 gas and B2H6 gas, and then a tungsten film is formed using WF6 gas and H2 gas. Instead of B2H6 gas, SiH()4 gas may be used.

[0144] For example, when forming an oxide semiconductor film, such as an In-Ga-ZnO film, using a film forming apparatus that utilizes ALD when forming the film, an In-O layer is formed using In(CH3)3 gas and O3 gas , and then, a GaO layer is formed using Ga(CH3)3 gas and O3 gas, and further, a ZnO layer is formed using Zn (CH3)2 gas and O3 gas. Note that the order of these layers is not limited to this example. Also, these gases may be mixed to form a mixed compound layer such as an In-Ga-O layer, an In-Zn-O layer , a Ga-Zn-O layer, etc. Note that instead of O3 gas, H2O gas obtained by bubbling with an inert gas such as Ar may be used, but it is preferable to use O 3 gas that does not contain H. Also, instead of In(CH3)3 gas, In(C2H5) 3 gas may be used. Also, instead of Ga(CH3)3 gas, Ga(C2H5)3 gas may be used. Also, Zn(CH3)2 gas may be used.

[0145] <1-6. Configuration Example 2 of Semiconductor Device> Next, a modified example of the semiconductor device 100 shown in FIGS. 1(A) and (B) will be described with reference to FIGS. 4(A) and (B) and FIG. 5.

[0146] FIG. 4(A) is a cross-sectional view of a modified example of the semiconductor device 100 shown in FIG. 1(B), and FIG. 4(B ) is a cross-sectional view of a modified example of the semiconductor device 100 shown in FIG. 1(B), and FIG. 5 is a cross-sectional view of a modified example of the semiconductor device 100 shown in FIG. 1(B) .

[0147] FIG. 4(A) shows a configuration in which the conductive film 122c that functions as the second gate electrode of the transistor Tr1 included in the semiconductor device 100 is not provided.

[0148] FIG. 4(B) shows the second gate electrode of the transistor Tr2 included in the semiconductor device 100​ The conductive film 130 functions, and the insulating film 134 is not provided on the conductive film 130. Also, in FIG. 4(B), instead of the opening 182 provided in the insulating film 124 and the insulating film 126, and the opening 184 provided in the insulating film 134 and the insulating film 136, a configuration is adopted in which an opening 183 is provided in the insulating film 124, the insulating film 126, and the insulating film 136. Thus, by having only one opening, the manufacturing process can be reduced, which is preferable.

[0149] FIG. 5 shows a configuration in which the conductive film 122c functions as the second gate electrode of the transistor Tr1 included in the semiconductor device 100, the conductive film 130 functions as the second gate electrode of the transistor Tr2, and the insulating film 134 is not provided on the conductive film 130. Also, similar to FIG. 4(B), a configuration is adopted in which an opening 183 is provided in the insulating film 124, the insulating film 126, and the insulating film 136.

[0150] <1-7. Configuration Example 3 of Semiconductor Device> Next, a modified example of the semiconductor device 100 shown in FIGS. 1(A) and 1(B) will be described with reference to FIGS. 6(A), 6(B), and FIG. 7.

[0151] Here, the stacked structure of the oxide semiconductor film will be described

[0152] FIGS. 6(A) and 6(B) are cross-sectional views of the transistor Tr1 included in the semiconductor device 100 in the channel length (L) direction.

[0153] FIG. 6(A) shows a configuration in which the oxide semiconductor film 108 included in the transistor Tr1 has an oxide semiconductor film 108a, an oxide semiconductor film 108b on the oxide semiconductor film 108a, and an oxide semiconductor film 108c on the oxide semiconductor film 108b. That is, the oxide semiconductor film ​​​​​​​ It has a three-layer stacked structure.

[0154] FIG. 6(B) shows a configuration in which the oxide semiconductor film 108 included in the transistor Tr1 includes an oxide semiconductor film 108b and an oxide semiconductor film 108c on the oxide semiconductor film 108b. That is, the oxide semiconductor film has a two-layer stacked structure.

[0155] An example of the band structure of the insulating film in contact with the oxide semiconductor film 108 and the oxide semiconductor film 108 is shown in FIGS. 7(A) and 7(B).

[0156] FIG. 7(A) shows an example of the band structure in the film thickness direction of a stacked structure including an insulating film 106, oxide semiconductor films 108a, 108b, 108c, and an insulating film 114. FIG. 7(B) shows an example of the band structure in the film thickness direction of a stacked structure including an insulating film 106, oxide semiconductor films 108b, 108c, and an insulating film 114. Note that the band structure shows the energy level (Ec) at the lower end of the conduction band of the insulating film 106, the oxide semiconductor films 108a, 108b, 108c, and the insulating film 114 for easy understanding.

[0157] Also, in FIG. 7(A), silicon oxide films are used as the insulating film 106 and the insulating film 114, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 for the oxide semiconductor film 108a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 for the oxide semiconductor film 108b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 for the oxide semiconductor film 108c. This is a band diagram of the configuration. ​​​​​​

[0158] Further, in FIG. 7(B), a silicon oxide film is used as the insulating film 106 and the insulating film 114, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of metal elements of In:Ga:Zn = 4:2:4.1 is used, and for the oxide semiconductor film 10 8c, a metal oxide film formed using a metal oxide target with an atomic ratio of metal elements of In:Ga:Zn = 1:3:2 is used, which is a band diagram of the configuration.

[0159] As shown in FIGS. 7(A) and 7(B), in the oxide semiconductor films 108a, 108b, and 108c, the energy level at the lower end of the conduction band changes gently. In other words, it can be said that they change continuously or are continuously joined. For such a band structure to exist, at the interface between the oxide semiconductor film 108a and the oxide semiconductor film 108b, or at the interface between the oxide semiconductor film 108b and the oxide semiconductor film 108c, it is assumed that there are no impurities that form defect levels such as trap centers or recombination centers.

[0160] To form a continuous junction in the oxide semiconductor films 108a, 108b, and 108c, it is necessary to continuously stack each film without exposing it to the atmosphere using a multi-chamber film-forming apparatus (sputtering apparatus) equipped with a load lock chamber.

[0161] With the configuration shown in FIGS. 7(A) and 7(B), the oxide semiconductor film 108b becomes a well, and in the transistor using the above-described stacked structure, it can be seen that the channel region is formed in the oxide semiconductor film 10 8b.

[0162] Note that by providing the oxide semiconductor films 108a and 108c, the trap levels can be moved farther from the oxide semiconductor film 108b.

[0163] In addition, the trap levels may be farther from the vacuum level than the energy level (Ec) at the lower end of the conduction band of the oxide semiconductor film 108b that functions as a channel region, and electrons are likely to accumulate in the trap levels. When electrons accumulate in the trap levels, they become negative fixed charges, and the threshold voltage of the transistor shifts in the positive direction. Therefore, it is preferable to configure the trap levels to be closer to the vacuum level than the energy level (Ec) at the lower end of the conduction band of the oxide semiconductor film 108b. By doing so, it becomes difficult for electrons to accumulate in the trap levels, and it is possible to increase the on-current of the transistor and increase the field-effect mobility.

[0164] Also, the oxide semiconductor films 108a and 108c have an energy level at the lower end of the conduction band closer to the vacuum level than that of the oxide semiconductor film 108b. Typically, the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 108b and the energy levels at the lower ends of the conduction bands of the oxide semiconductor films 108a and 108c is 0.15 eV or more, or 0.5 eV or more, and 2 eV or less, or 1 eV or less. That is, the difference between the electron affinities of the oxide semiconductor films 108a and 108c and the electron affinity of the oxide semiconductor film 108b is 0.15 eV or more, or 0.5 eV or more, and 2 eV or less, or 1 eV or less.

[0165] By having such a configuration, the oxide semiconductor film 108b becomes the main path of the current, and ​​​​​​​​​​​​​functions as a channel region. Further, the oxide semiconductor films 108a and 108c are oxide semiconductor films composed of one or more of the metal elements constituting the oxide semiconductor film 108b in which the channel region is formed, so that interface scattering hardly occurs at the interface between the oxide semiconductor film 108a and the oxide semiconductor film 108b, or at the interface between the oxide semiconductor film 108b and the oxide semiconductor film 108c. Therefore, since the movement of carriers is not inhibited at the interface, the field-effect mobility of the transistor becomes high. Also, in order to prevent the oxide semiconductor films 108a and 108c from functioning as a part of the channel region, a material having a sufficiently low conductivity is used. Alternatively, the oxide semiconductor films 108a and 108c use a material having an electron affinity (the difference between the vacuum level and the energy level at the lower end of the conduction band) smaller than that of the oxide semiconductor film 108b and having a difference (band offset) in the energy level at the lower end of the conduction band from the energy level at the lower end of the conduction band of the oxide semiconductor film

[0166] 108b. Further, in order to suppress the occurrence of a difference in threshold voltage depending on the magnitude of the drain voltage, it is preferable to use a material in which the energy level at the lower end of the conduction band of the oxide semiconductor films 108a and 108c is closer to the vacuum level than the energy level at the lower end of the conduction band of the oxide semiconductor film 108b. For example, the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 108b and the energy levels at the lower ends of the conduction bands of the oxide semiconductor films 108a and 108c is preferably 0.2 eV or more, more preferably 0.5 eV or more. 108a and 108c. Also, the oxide semiconductor films 108a and 108c do not contain a spinel-type crystal structure in the film. 108b. In addition, in order to suppress the occurrence of a difference in threshold voltage depending on the magnitude of the drain voltage, the energy level at the lower end of the conduction band of the oxide semiconductor films 108a and 108c is preferably closer to the vacuum level than the energy level at the lower end of the conduction band of the oxide semiconductor film 108b. For example, the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 108b and the energy levels at the lower ends of the conduction bands of the oxide semiconductor films 108a and 108c is preferably 0.2 eV or more, more preferably 0.5 eV or more. It is preferable to use a material closer to the vacuum level than the energy level at the lower end of the conduction band of the oxide semiconductor film 108b. For example, the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 108b and the energy levels at the lower ends of the conduction bands of the oxide semiconductor films 108a and 108c is preferably 0.2 eV or more, more preferably 0.5 eV or more. For example, the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 108b and the energy levels at the lower ends of the conduction bands of the oxide semiconductor films 108a and 108c is preferably 0.2 eV or more, more preferably 0.5 eV or more. is 0.2 eV or more, preferably 0.5 eV or more. It is preferable that the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 108b and the energy levels at the lower ends of the conduction bands of the oxide semiconductor films 108a and 108c is 0.2 eV or more, preferably 0.5 eV or more.

[0167] Further, the oxide semiconductor films 108a and 108c do not contain a spinel-type crystal structure in the film. It is preferable that the oxide semiconductor films 108a and 108c have a spinel crystal structure. When the spinel type crystal structure is contained, the conductive film 112a, 11 The constituent elements of 2b may diffuse into the oxide semiconductor film 108b. When the conductive films 108a and 108c are made of CAAC-OS, which will be described later, the conductive films 112a and 11 This is preferable because it increases the blocking ability of the constituent elements of 2b, for example, copper element.

[0168] The thicknesses of the oxide semiconductor films 108a and 108c are determined by the amount of the constituent elements of the conductive films 112a and 112b. The insulating film has a thickness that is greater than or equal to a thickness that can prevent the insulating film from diffusing into the oxide semiconductor film 108b. The thickness of the oxide semiconductor film 108b is set to be less than the thickness that prevents oxygen from being supplied from the film 114 to the oxide semiconductor film 108b. When the thickness of the oxide semiconductor films 108a and 108c is 10 nm or more, the conductive films 112a and This can prevent the constituent elements of the oxide semiconductor film 112b from diffusing into the oxide semiconductor film 108b. In addition, when the thickness of the oxide semiconductor films 108a and 108c is 100 nm or less, the insulating film 114 Oxygen can be effectively supplied from the oxide semiconductor film 108b to the oxide semiconductor film 108b.

[0169] The oxide semiconductor films 108a and 108c are made of In-M-Zn oxide (M is Al, Ga, Y, or When M is present in a higher atomic ratio than In, the oxide semiconductor film 10 The energy gap of 8a and 108c can be increased and the electron affinity can be reduced. The difference in electron affinity between the compound semiconductor film 108b and the compound semiconductor film 108a can be controlled by the composition of M. In addition, M is a metal element that has a strong bond with oxygen, so these elements can be combined with I By having an atomic ratio higher than n, oxygen deficiency is less likely to occur.

[0170] Also, when the oxide semiconductor films 108a and 108c are In-M-Zn oxides, the atomic ratio of In and M excluding Zn and O is preferably less than 50 atomic% for In and higher than 50 atomic% for M. More preferably, In is less than 25 atomic% and M is higher than 75 atomic%. Further, a gallium oxide film may be used as the oxide semiconductor films 108a and 108c.

[0171] Also, when the oxide semiconductor films 108a, 108b, and 108c are In-M-Zn oxides, the atomic ratio of M contained in the oxide semiconductor films 108a and 108c is larger than that in the oxide semiconductor film 108b. Typically, it is 1.5 times or more, preferably 2 times or more, and more preferably 3 times or more higher than the above atoms contained in the oxide semiconductor film 108b.

[0172] Also, when the oxide semiconductor films 108a, 108b, and 108c are In-M-Zn oxides, if the oxide semiconductor film 108b is In:M:Zn = x1:y1:z1 [atomic ratio] and the oxide semiconductor films 108a and 108c are In:M:Zn = x2:y2:z2 [atomic ratio], then y2 / x2 is larger than y1 / x1. Preferably, y2 / x2 is 1.5 times or more than y1 / x1. More preferably, y2 / x2 is 2 times or more larger than y1 / x1, and even more preferably, y2 / x2 is 3 times or more or 4 times or more larger than y1 / x1. At this time, in the oxide semiconductor film 108b, if y1 is equal to or more than x1, it is preferable because stable electrical characteristics can be imparted to the transistor using the oxide semiconductor film 108b. However, when y1 becomes 3 times or more of x1, the field-effect mobility of the transistor using the oxide semiconductor film 108b will decrease.​​​​​​​​​​​​​​​ Since it will decrease, it is preferable that y1 is less than three times x1.

[0173] When the oxide semiconductor film 108b is an In-M-Zn oxide, in the target used to form the oxide semiconductor film 108b, the atomic ratio of the metal elements is In:M:Zn = x1: y1:z1, then y1:z1, then 、 x1 / y1 is 1 / 3 or more and 6 or less, and further 1 or more and 6 or less, and it is preferable that z1 / y1 is 1 / 3 or more and 6 or less, and further 1 or more and 6 or less. Note that by setting z1 / y1 to 1 or more and 6 or less, CAA C-OS described later is likely to be formed as the oxide semiconductor film 108b. Representative examples of the atomic ratio of the metal elements in the target include I n:M:Zn = 4:2:4.1, In:M:Zn = 1:1:1.2, In:M:Zn = 3 :1:2, etc.

[0174] Also, when the oxide semiconductor films 108a and 108c are In-M-Zn oxides, in the targets used to form the oxide semiconductor films 108a and 108c, the atomic numbers of the metal elements ratio is In:M:Zn = x2:y2:z2, then ratio is In:M:Zn = x2:y2:z2, then 、 x2 / y2 < x1 / y1, and z 2 / y2 is preferably 1 / 3 or more and 6 or less, and further 1 or more and 6 or less. Also, by increasing the atomic ratio of M to In, the energy gap of the oxide semiconductor films 108a and 108c can be increased and the electron affinity can be decreased. Therefore, it is preferable that y2 / x2 is 3 or more, or 4 or more. Representative examples of the atomic ratio of the metal elements in the target include In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Z n = 1:3:5, In:M:Zn = 1:3:6, In:M:Zn = 1:4:2, In:M n = 1:3:5, In:M:Zn = 1:3:6, In:M:Zn = 1:4:2, In:M : There are, for example, Zn=1:4:4, In:M:Zn=1:4:5, In:M:Zn=1:5:5, etc. exist.

[0175] Further, when the oxide semiconductor films 108a and 108c are In-M oxides, by adopting a configuration that does not contain divalent metal atoms (for example, zinc, etc.) as M, oxide semiconductor films 108a and 108c that do not contain a spinel-type crystal structure can be formed. Also, as the oxide semiconductor films 108a and 108c, for example, an In-Ga oxide film can be used. As the In-Ga oxide film, for example, it can be formed by a sputtering method using an In-Ga metal oxide target (In:Ga = 7:93). Also, in order to form the oxide semiconductor films 108a and 108c by a sputtering method using DC discharge, when In:M = x:y [atomic ratio], y / (x + y) should be 0.96 or less, preferably 0.95 or less, for example, 0.93. Note that the atomic ratios of the oxide semiconductor films 108a, 108b, and 108c each include fluctuations of plus or minus 40% of the above atomic ratios as errors. In the case of the oxide semiconductor film of the transistor Tr1, a two-layer and a three-layer laminated structure are illustrated in FIGS. 6(A) and 6(B). However, the oxide semiconductor film 12 8 of the transistor Tr2 may have a similar configuration. That is, as the semiconductor device of the present invention, it may be applied by changing the presence or absence of the second gate electrode or the laminated structure of the oxide semiconductor film. Also, the transistor according to the present embodiment can freely combine each of the above structures.

[0176]

[0177]

[0178] ​

[0179] <1-8. Manufacturing method of semiconductor device> Next, a manufacturing method of the semiconductor device 100 of one embodiment of the present invention will be described with reference to FIGS. I will explain.

[0180] 8(A), 9(A), 10(A), 11(A), 12(A), and 13 14(A), 15(A), 16(A), and 17(A) are semiconductor devices. 8(B), 9(B), 10(B), and 11(C) are top views illustrating a method for manufacturing the semiconductor device 100. 11(B), Fig. 12(B), Fig. 13(B), Fig. 14(B), Fig. 15(B), Fig. 16(B) 17A and 17B are cross-sectional views illustrating a method for manufacturing the semiconductor device 100. FIG.

[0181] First, a conductive film is formed on the substrate 102, and the conductive film is then subjected to a lithography process and an etching process. Then, a conductive film 104 is formed, which functions as a first gate electrode. An insulating film 106 that functions as a first gate insulating film is formed on the conductive film 104 (FIG. 8(A)). (See (B)).

[0182] In this embodiment, a glass substrate is used as the substrate 102, and a gate electrode is formed on the substrate 102. As the conductive film 104, a tungsten film having a thickness of 100 nm is formed by sputtering. The insulating film 106 is made of a silicon nitride film having a thickness of 400 nm and a silicon nitride film having a thickness of 50 nm. A silicon oxynitride film is formed by the PECVD method.

[0183] The silicon nitride film used as the insulating film 106 has a stacked structure. The silicon nitride film is formed by stacking a first silicon nitride film, a second silicon nitride film, and a third silicon nitride film. It can be made into a three-layer laminated structure with a nitride film. As an example of the three-layer laminated structure, it is as follows It can be formed on.

[0184] As the first silicon nitride film, for example, silane with a flow rate of 200 sccm, nitrogen with a flow rate of 2000 sccm, and ammonia gas with a flow rate of 100 sccm are used as source gases and supplied to the reaction chamber of a PE-CVD device. The pressure in the reaction chamber is controlled to 100 Pa, and 2000 W of power is supplied using a 27.12 MHz high frequency power supply to form it to a thickness of 50 nm is fine.

[0185] As the second silicon nitride film, silane with a flow rate of 200 sccm, nitrogen with a flow rate of 2000 sccm and ammonia gas with a flow rate of 2000 sccm are used as source gases and supplied to the reaction chamber of a PECVD device The pressure in the reaction chamber is controlled to 100 Pa, and 2000 W of power is supplied using a 27.12 MHz high-frequency power supply to form it to a thickness of 300 nm.

[0186] As the third silicon nitride film, silane with a flow rate of 200 sccm and nitrogen with a flow rate of 5000 sc cm are used as source gases and supplied to the reaction chamber of a PECVD device. The pressure in the reaction chamber is 100 Pa, and 20XX W of power is supplied using a 27.12 MHz high-frequency power supply to form it to a thickness of 50 nm.

[0187] In addition, the substrate temperature during the formation of the first silicon nitride film, the second silicon nitride film, and the third silicon nitride film can be 350 °C or lower.

[0188] By making the insulating film 106 into a three-layer laminated structure of silicon nitride films, for example, the conductive film 10 It should be noted that in the above translation, "20XX W" in line 32 is a placeholder in the original text. If there is a specific correct value, it should be filled in accurately during translation. Also, some tags like etc. are preserved as they are according to the requirements.When using a conductive film containing copper (Cu) for 4, the following effects are achieved.

[0189] The first silicon nitride film can suppress the diffusion of copper (Cu) elements from the conductive film 104. The second silicon nitride film has a function of releasing hydrogen and can improve the breakdown voltage of the insulating film that functions as a gate insulating film. The third silicon nitride film has little hydrogen release from the third silicon nitride film and can suppress the diffusion of hydrogen released from the second silicon nitride film.

[0190] Next, an oxide semiconductor film 108 is formed on the insulating film 106 (see FIGS. 9(A) and 9(B)).

[0191] In this embodiment, an oxide semiconductor film is formed by sputtering using an In-Ga-Zn metal oxide target (In:Ga:Zn = 4: 2:4.1 [atomic ratio]). Also, the substrate temperature during the formation of the oxide semiconductor film is set to 170°C, and as the film-forming gas during the formation, oxygen gas with a flow rate of 60 sccm and argon gas with a flow rate of 140 sccm are used. After that, the oxide semiconductor film is processed into a desired shape to form an island-shaped oxide semiconductor film 108. Note that a wet etching apparatus is used for the formation of the oxide semiconductor film.

[0192] Next, a conductive film is formed on the insulating film 106 and the oxide semiconductor film 108, and the conductive film is processed into a desired shape to form conductive films 112a and 112b. After that, insulating films 114 and 116 are formed on the insulating film 106, the oxide semiconductor film 108, and the conductive films 112a and 112b (see FIGS. 10(A) and 10(B)).

[0193] In this embodiment, as the conductive films 112a and 112b, a tungsten film with a thickness of 50 nm , an aluminum film with a thickness of 100 nm, and a titanium film with a thickness of 50 nm are sequentially laminated , and the laminated film is formed by a sputtering method.

[0194] Further, after the formation of the conductive films 112a and 112b, the surface (back channel side) of the oxide semiconductor film 108 may be cleaned. Examples of the cleaning method include cleaning using an etchant such as an aqueous phosphoric acid solution. Thereby, impurities (for example, elements contained in the conductive films 112a and 112b) adhering to the surface of the oxide semiconductor film 108 can be removed. Note that it is not always necessary to perform such cleaning, and in some cases, cleaning may not be required.

[0195] In addition, in either one or both of the step of forming the conductive films 112a and 112b and the above cleaning step, the region of the oxide semiconductor film 108 exposed from the conductive films 112a and 112b may become thinner.

[0196] In this embodiment, a silicon oxynitride film with a thickness of 20 nm is used as the insulating film 114, and a silicon oxynitride film with a thickness of 200 nm is used as the insulating film 116, and they are respectively formed using the PECVD method.

[0197] Note that after forming the insulating film 114, it is preferable to continuously form the insulating film 116 without exposing it to the atmosphere. After forming the insulating film 114, without opening to the atmosphere, by adjusting one or more of the flow rate, pressure, high-frequency power, and substrate temperature of the source gas and continuously forming the insulating film 116, the impurity concentration derived from the atmospheric components at the interface between the insulating film 114 and the insulating film 116 can be reduced. while being able to move oxygen contained in the insulating films 114 and 116 to the oxide semiconductor film 108, it becomes possible to reduce the oxygen deficiency amount of the oxide semiconductor film 108. .

[0198] In this embodiment, as the insulating film 114, the temperature for holding the substrate 102 is set to 220°C, silane with a flow rate of 50 sccm and dinitrogen monoxide with a flow rate of 2000 sccm are used as source gases, the pressure in the processing chamber is set to 20 Pa, and the high-frequency power supplied to the parallel plate electrodes is 13.56 M Hz, 100 W (the power density is 1.6×10 -2 W / cm 2 ), and a silicon oxynitride film is formed using the PECVD method.

[0199] As the insulating film 116, the substrate placed in the vacuum-exhausted processing chamber of the PECVD apparatus is held at 180°C or higher and 350°C or lower, and source gases are introduced into the processing chamber to set the pressure in the processing chamber to 100 Pa or higher and 250 Pa or lower, more preferably 100 Pa or higher and 200 Pa or lower, and a high-frequency power of 0.17 W / cm or higher and 0.5 W / cm 2 or lower, more preferably 0.25 W / cm 2 or higher and 0.35 W / cm or lower is supplied to the electrodes provided in the processing chamber, 2 and a silicon oxide film or a silicon oxynitride film is formed under these conditions. 2

[0200] As the film formation conditions for the insulating film 116, by supplying the high-frequency power with the above power density in the reaction chamber with the above pressure, the decomposition efficiency of the source gases in the plasma increases, the oxygen radicals increase, and the oxidation of the source gases proceeds, so the oxygen content in the insulating film 116 becomes higher 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 the oxygen satisfying the stoichiometric composition and from which a part of the oxygen desorbs by heating insulating film can be formed.

[0201] In the formation process of the insulating film 116, the insulating film 114 serves as a protective film for the oxide semiconductor film 108. Therefore, the insulating film 116 can be formed using high-frequency power with a high power density while reducing damage to the oxide semiconductor film 108.

[0202] In addition, in the film formation conditions of the insulating film 116, by increasing the flow rate of the deposition gas containing silicon with respect to the oxidizing gas, it is possible to reduce the defect amount of the insulating film 116. 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 3 and preferably less than 3 × 10 17 spins / cm 3 and preferably less than 1.5 × 10 17 spins / cm 3 an oxide insulating film with a small defect amount can be formed. As a result, the reliability of the transistor Tr1 can be improved.

[0203] In addition, it is preferable to perform a heat treatment (hereinafter referred to as the first heat treatment ) after forming the insulating films 114 and 116. By the first heat treatment, the nitrides contained in the insulating films 114 and 116 can be reduced. Or, by the first heat treatment, the insulating films 114 and 116 Part of the oxygen contained is transferred to the oxide semiconductor film 108, and the oxygen deficiency amount contained in the oxide semiconductor film 108 can be reduced.

[0204] The temperature of the first heat treatment is typically less than 400 °C, preferably less than 375 °C, and more preferably 150 °C or more and 350 °C or less. The first heat treatment may be performed in an atmosphere of nitrogen, oxygen, ultra-dry air (water content of 20 ppm or less, preferably 1 ppm or less, preferably 10 ppb or less of air), or a noble gas (argon, helium, etc.). Note that it is preferable that hydrogen, water, etc. are not contained in the above nitrogen, oxygen, ultra-dry air, or noble gas. For this heat treatment, an electric furnace, RTA (Rapid Thermal Anneal), etc. can be used.

[0205] Next, an oxide semiconductor film 128 is formed on the insulating film 116 (see FIGS. 11(A) and 11(B)).

[0206] In this embodiment, an oxide semiconductor film is formed by a sputtering method using an In-Ga-Zn metal oxide target (In:Ga:Zn = 4:2:4.1 [atomic ratio]). Further, the substrate temperature during the formation of the oxide semiconductor film is 170 °C, and as the film-forming gas during the formation, oxygen gas with a flow rate of 60 sccm and argon gas with a flow rate of 140 sccm are used. Then, by processing the oxide semiconductor film into a desired shape, an island-shaped oxide semiconductor film 128 is formed. Note that a wet etching apparatus is used for the formation of the oxide semiconductor film.

[0207] Next, conductive films 122a, 122b, and 122c are formed on the insulating film 116 and the oxide semiconductor film 128, and then, the insulating film 116, the oxide semiconductor film 128, and the conductive films 122a, 1 ​​​​​​​​​​​​​​ Insulating films 124 and 126 are formed on 22b and 122c (see FIGS. 12(A) and (B)).

[0208] As the conductive films 122a, 122b, and 122c, they can be formed by the same method as the previously shown conductive films 112a and 112b. Also, as the insulating films 124 and 126, they can be formed by the same method as the previously shown insulating films 114 and 116.

[0209] Next, openings 182 that reach the conductive film 122a are formed in desired regions of the insulating films 124 and 126. After that, a conductive film 130 is formed on the insulating film 126 and the conductive film 122a (see FIGS. 13(A) and (B)).

[0210] For the formation of the openings 182, a dry etching apparatus or a wet etching apparatus is used. Also, as the conductive film 130, an oxide (also referred to as ITO) target having indium, tin, and silicon (In2O3:SnO2:SiO2 = 85:10:5 [by weight %]) is used to form an ITO film with a thickness of 100 nm, and then it is processed into an island shape.

[0211] Next, a laminated film of an insulating film that becomes the insulating film 134 and an insulating film that becomes the insulating film 136 is formed on the insulating film 126 and the conductive film 130. After that, openings 184 that reach the conductive film 130 are formed in desired regions of the laminated film (see FIGS. 14(A) and (B)).

[0212] As the insulating film 134, a silicon oxynitride film with a thickness of 200 nm is formed using the PECVD method. Also, as the insulating film 136, a photosensitive acrylic-based organic resin film with a thickness of 1.5 μm is formed.

[0213] ​​​​To form the opening 184, a dry etching apparatus or a wet etching apparatus is used. This is done.

[0214] Next, a conductive film is formed on the insulating film 136 and the conductive film 130, and the conductive film is processed into an island shape to form the conductive film 138 (see FIGS. 15(A) and (B)). This is done.

[0215] In this embodiment, as the conductive film 138, a laminated film of an ITSO film with a thickness of 10 nm, a reflective metal film with a thickness of 200 nm (here, a metal film containing silver, palladium, and copper), and an ITSO film with a thickness of 10 nm is used. Also, for processing the conductive film 138, a wet etching apparatus is used. This is done. Next, an island-shaped insulating film 140 is formed on the insulating film 136 and the conductive film 138 (see FIGS. 16(A) and (B)). This is done.

[0216] As the insulating film 140, a photosensitive polyimide-based organic resin film with a thickness of 1.5 μm is used. This is done.

[0217] This is done. This is done.

[0218] Next, an EL layer 142 is formed on the conductive film 138, and then a conductive film 144 is formed on the insulating film 140 and the EL layer 142 to form the light-emitting element 160 (see FIGS. 17(A) and (B)). This is done. This is done.

[0219] Note that the method for forming the light-emitting element 160 will be described in detail in Embodiment 3.

[0220] Through the above steps, the semiconductor device 100 shown in FIGS. 1(A) and (B) can be formed.

[0221] Note that the configurations and methods shown in this embodiment can be used in appropriate combination with the configurations and methods shown in other embodiments. This is done.

[0222] (Embodiment 2) In this embodiment, a semiconductor device and a method for manufacturing the semiconductor device according to an aspect of the present invention will be described with reference to FIGS. 18 to 29. See FIGS. 18 to 29 for the description.

[0223] <2-1. Configuration Example 1 of Semiconductor Device> FIG. 18(A) is a top view of a semiconductor device 200 according to an aspect of the present invention, and FIG. 18(B) is corresponding to a cross-sectional view of a cut surface between the dashed-dotted line A1 - A2 shown in FIG. 18(A). Note that FIG. 18(B) includes a cross-section in the channel length (L) direction of the transistor Tr1 and a cross-section in the channel length (L) direction of the transistor Tr2.

[0224] The semiconductor device 100 shown in FIGS. 18(A) and 18(B) has a transistor Tr1 and a transistor Tr2 at least partially overlapping with Tr1. Note that the transistor Tr1 is a transistor with a bottom gate structure, and the transistor Tr2 is a transistor with a top gate structure.

[0225] By providing a region where the transistor Tr1 and the transistor Tr2 at least partially overlap with each other, the layout area of the transistors can be reduced.

[0226] The transistor Tr1 includes a conductive film 104 on a substrate 102, an insulating film 106 on the substrate 102 and the conductive film 104, an oxide semiconductor film 108 on the insulating film 106, a conductive film 112a on the oxide semiconductor film 108, a conductive film 112b on the oxide semiconductor film 108, an insulating film 114 on the oxide semiconductor film 108, the conductive film 112a, and the conductive film 112b, an insulating film 116 on the insulating film 114, an insulating film 118 on the insulating film 116, an insulating film 119 on the insulating film 118, and an insulating film on the insulating film 118, an insulating film 119 on the insulating film 118, and an insulating film on the insulating film 118, an insulating film 119 on the insulating film 118, and an insulating film on the insulating film 118, an insulating film 119 on the insulating film 118, and an insulating film on the insulating film 118, an insulating film 119 on the insulating film 118, and an insulating It has an insulating film 210a on the film 119 and a conductive film 212a on the insulating film 210a.

[0227] Further, the transistor Tr2 has a conductive film 112c and an insulating film 114 on the conductive film 112c , an insulating film 116 on the insulating film 114, an insulating film 118 on the insulating film 116, and on the insulating film 118 an insulating film 119, an oxide semiconductor film 208 on the insulating film 119, and on the oxide semiconductor film 208 an insulating film 210b, a conductive film 212b on the insulating film 210b, the oxide semiconductor film 208, and an insulating film 214 on the conductive film 212b, an insulating film 216 on the insulating film 214, and on the insulating film 216 a conductive film 218a provided thereon and electrically connected to the oxide semiconductor film 208, and an insulating film 21 a conductive film 218b provided on 6 and electrically connected to the oxide semiconductor film 208. It has.

[0228] Note that, as shown in FIGS. 18(A) and (B), the oxide semiconductor film 108 and the oxide semiconductor film 2 08 have an overlapping region with each other.

[0229] The oxide semiconductor film 108 can have the same configuration as that shown in Embodiment 1. The oxide semiconductor film 208 can have the same configuration as the oxide semiconductor film 128 shown in Embodiment 1.

[0230] Therefore, the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 exceeds 10 cm 2 / Vs, and more preferably, the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 exceeds 30 cm 2 / Vs. This makes it possible.

[0231] For example, by using the above transistor with high field-effect mobility in the gate driver that generates the gate signal of the display device, a display device with a narrow frame width (also referred to as a narrow-frame) can be provided. Further, by using the above transistor with high field-effect mobility in the source driver (particularly, the demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies the signal from the signal line of the display device, a display device with a small number of subsequent wirings can be provided. Also, by using the above transistor with high field-effect mobility in either one or both of the selection transistor and the drive transistor of the pixel circuit of the display device, a display device with high display quality can be provided. Moreover, the semiconductor device 100 shown in FIGS. 18(A) and 18(B) can be suitably used in the pixel circuit of the display device, and by arranging it as shown in FIGS. 18(A) and 18(B), the pixel density of the display device can be increased. For example, even when the pixel density of the display device exceeds 1000 ppi or the pixel density of the display device exceeds 2000 ppi, by arranging it as shown in FIGS. 18(A) and 18(B), the aperture ratio of the pixel can be increased. In addition, when the semiconductor device 100 shown in FIGS. 18(A) and 18(B) is applied to the pixel circuit of the display device, it can have the same configuration as the pixel circuit shown in FIG. 2. Furthermore, when the semiconductor device 100 shown in FIGS. 18(A) and 18(B) is applied to the pixel of the display device, for example, the channel length (L) and channel width (W) of the transistor, or the transistor

[0232]

[0233]

[0234] ​​​​​​​​​​​The wiring connected thereto and the line width of the electrodes can be made relatively large. For example, when transistors Tr1 and Tr2 are arranged on the same plane, as shown in FIGS. 18(A )(B), at least a part of transistor Tr1 and transistor Tr2 are overlapped and arranged, so that the line width and the like can be increased, and the variation in the processing dimensions can be reduced.

[0235] In addition, for transistor Tr1 and transistor Tr2, either one or both of the conductive film and the insulating film can be commonly used, so that the number of masks or the number of processes can be reduced which is possible.

[0236] For example, in transistor Tr1, the conductive film 104 functions as the first gate electrode , the conductive film 112a functions as the source electrode, the conductive film 112b functions as the drain electrode , and the conductive film 212a functions as the second gate electrode. Also, in transistor Tr1 , the insulating film 106 functions as the first gate insulating film, and the insulating films 114, 116, 118 , 119, 210a function as the second gate insulating film. Also, in transistor Tr2 , the conductive film 112c functions as the first gate electrode, the conductive film 218a functions as the source electrode , the conductive film 218b functions as the drain electrode, and the conductive film 212b functions as the second gate electrode. Also, in transistor Tr2, the insulating films 114, 116, 118, 119 function as the first gate insulating film, and the insulating film 210b functions as the second gate insulating film.

[0237] Note that in this specification and the like, the insulating film 210a is referred to as the fourth insulating film, and the insulating film 210b is referred to as the fifth The insulating film may be referred to as such, respectively.

[0238] In addition, an insulating film 136 is provided on the insulating film 216 and the conductive films 218a and 218b. An opening 186 reaching the conductive film 218b is provided in the insulating film 136. Also A conductive film 138 is provided on the insulating film 136. Note that the conductive film 138 is connected to the conductive film 218b through the opening 186.

[0239] An insulating film 140, an EL layer 142, and a conductive film 144 are provided on the conductive film 138. Also, a light-emitting element 160 is formed by the conductive film 138, the EL layer 142, and the conductive film 144. 0 is formed.

[0240] Thus, in one aspect of the present invention, a transistor having a bottom gate structure and a transistor having a top gate structure can be used in combination.

[0241] Although not shown in the drawings, the transistors Tr1 and transistor Tr2 shown in FIGS. 18(A) and (B) may have the S-channel structure described in Embodiment 1.

[0242] Also, the transistors Tr1 and Tr2 included in the semiconductor device 200 shown in the present embodiment and the transistors Tr1 and Tr2 included in the semiconductor device 100 shown in Embodiment 1 can be used in combination.

[0243] ? As described above, a semiconductor device according to one aspect of the present invention has a stacked structure of a plurality of transistors, reducing the installation area of the transistors. Also, in the plurality of transistors, by commonly using either one or both of the insulating film and the conductive film, the number of masks or the number of processes is reduced. It can be reduced.

[0244] <2-2. Components of the semiconductor device> Next, the components included in the semiconductor device of this embodiment will be described in detail.

[0245] [Conductive film] As the conductive films 212a, 212b, 218a, and 218b, the conductive films described in Embodiment 1 (conductive film 104, conductive film 112a, conductive film 112b, conductive film 122a, conductive film 122b , conductive film 122c, conductive film 130, conductive film 138, and conductive film 144) can be used. In particular, when an oxide conductor (OC) is used for the conductive films 212a and 212b, it is suitable because oxygen can be added to the insulating films 210a and 210b.

[0246] [Insulating film] As the insulating films 118, 119, 214, 216, 210a, and 210b, the insulating films described in Embodiment 1 (insulating film 106, insulating film 114, insulating film 116, insulating film 124, insulating film 1 26, insulating film 134, insulating film 136, and insulating film 140) can be used.

[0247] In particular, when a silicon nitride film or a silicon oxynitride film is used as the insulating film 118, it is suitable because impurities entering the transistor Tr1 can be suppressed. Also, as the insulating film 119 , since it is in contact with the oxide semiconductor film 208, an oxide insulating film is preferable, and in particular, a silicon oxide film or a silicon oxynitride film is preferable. Also, as the insulating films 210a and 210b , it is preferably an oxide insulating film, and more preferably has a region containing oxygen in excess of the stoichiometric composition (excess oxygen region). As the insulating films 210a and 210b, an acid It is preferable to use a silicon nitride film or a silicon oxynitride film.

[0248] Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region. Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region. Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region. Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region. Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region. Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region. Further, the insulating film 214 contains either one or both of hydrogen and nitrogen. Or, the insulating film 214 contains nitrogen and silicon. Further, the insulating film 214 has a function of blocking oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. When the oxide semiconductor film 208 is in contact with the insulating film 214, either one or both of hydrogen and nitrogen in the insulating film 214 enter the oxide semiconductor film 208, and the carrier density of the oxide semiconductor film 208 can be increased. Therefore, the region in the oxide semiconductor film 208 where the oxide semiconductor film 208 is in contact with the insulating film 214 functions as a source region or a drain region.

[0249] [Oxide semiconductor film] As the oxide semiconductor film 208, the materials of the oxide semiconductor films (oxide semiconductor film 108 and oxide semiconductor film 128) described in Embodiment 1 can be used. As the oxide semiconductor film 208, the materials of the oxide semiconductor films (oxide semiconductor film 108 and oxide semiconductor film 128) described in Embodiment 1 can be used.

[0250] <2-3. Method for manufacturing a semiconductor device> Next, a method for manufacturing the semiconductor device 200 according to an aspect of the present invention will be described with reference to FIGS. 19 to 29. Next, a method for manufacturing the semiconductor device 200 according to an aspect of the present invention will be described with reference to FIGS. 19 to 29.

[0251] Note that FIGS. 19(A), 20(A), 21(A), 22(A), 23(A), 24(A), 25(A), 26(A), 27(A), 28(A), and 29(A) are top views for explaining the method for manufacturing the semiconductor device 200, and FIGS. 19(B), 20(B), 21(B), 22(B), 23(B), 24(B), 25(B), 26(B), 27(B), 28(B), and 29(B) are cross-sectional views for explaining the method for manufacturing the semiconductor device 200. Note that FIGS. 19(A), 20(A), 21(A), 22(A), 23(A), 24(A), 25(A), 26(A), 27(A), 28(A), and 29(A) are top views for explaining the method for manufacturing the semiconductor device 200, and FIGS. 19(B), 20(B), 21(B), 22(B), 23(B), 24(B), 25(B), 26(B), 27(B), 28(B), and 29(B) are cross-sectional views for explaining the method for manufacturing the semiconductor device 200. Note that FIGS. 19(A), 20(A), 21(A), 22(A), 23(A), 24(A), 25(A), 26(A), 27(A), 28(A), and 29(A) are top views for explaining the method for manufacturing the semiconductor device 200, and FIGS. 19(B), 20(B), 21(B), 22(B), 23(B), 24(B), 25(B), 26(B), 27(B), 28(B), and 29(B) are cross-sectional views for explaining the method for manufacturing the semiconductor device 200. Note that FIGS. 19(A), 20(A), 21(A), 22(A), 23(A), 24(A), 25(A), 26(A), 27(A), 28(A), and 29(A) are top views for explaining the method for manufacturing the semiconductor device 200, and FIGS. 19(B), 20(B), 21(B), 22(B), 23(B), 24(B), 25(B), 26(B), 27(B), 28(B), and 29(B) are cross-sectional views for explaining the method for manufacturing the semiconductor device 200. Note that FIGS. 19(A), 20(A), 21(A), 22(A), 23(A), 24(A), 25(A), 26(A), 27(A), 28(A), and 29(A) are top views for explaining the method for manufacturing the semiconductor device 200, and FIGS. 19(B), 20(B), 21(B), 22(B), 23(B), 24(B), 25(B), 26(B), 27(B), 28(B), and 29(B) are cross-sectional views for explaining the method for manufacturing the semiconductor device 200. 10A to 10C are cross-sectional views illustrating a method.

[0252] First, a conductive film is formed on the substrate 102, and the conductive film is then subjected to a lithography process and an etching process. Then, a conductive film 104 is formed, which functions as a first gate electrode. An insulating film 106 that functions as a first gate insulating film is formed on the conductive film 104 (FIG. 19(A)). )(see B)).

[0253] In this embodiment, a glass substrate is used as the substrate 102, and a gate electrode is formed on the substrate 102. As the conductive film 104, a tungsten film having a thickness of 100 nm is formed by sputtering. The insulating film 106 is made of a silicon nitride film having a thickness of 400 nm and a silicon nitride film having a thickness of 50 nm. A silicon oxynitride film is formed by the PECVD method.

[0254] Next, the oxide semiconductor film 108 is formed over the insulating film 106 (see FIGS. 20A and 20B). .

[0255] In this embodiment, an In-Ga-Zn metal oxide target (In:Ga:Zn=4: 2:4.1 [atomic ratio]) to form an oxide semiconductor film by sputtering. The substrate temperature during the formation of the oxide semiconductor film was set to 170° C., and the film-forming gas during the formation was set to 1000 ppm. The flow rate of oxygen gas is 60 sccm and the flow rate of argon gas is 140 sccm. Thereafter, the oxide semiconductor film is processed into a desired shape to form an island-shaped oxide semiconductor film 1 08. Note that a wet etching apparatus is used to form the oxide semiconductor film.

[0256] Next, a conductive film is formed over the insulating film 106 and the oxide semiconductor film 108. By processing into the shape of, the conductive films 112a, 112b, and 112c are formed. Then, the insulating films 106, the oxide semiconductor film 108, and the insulating films 114, 116, 118, and 119 on the conductive films 112a, 112b, and 112c are formed (see FIGS. 21(A) and (B)).

[0257] In this embodiment, as the conductive films 112a, 112b, and 112c, a tungsten film with a thickness of 50 nm, an aluminum film with a thickness of 100 nm, and a titanium film with a thickness of 50 nm are sequentially stacked, and the stacked film is formed by sputtering.

[0258] Also, in this embodiment, a silicon oxynitride film with a thickness of 20 nm is used as the insulating film 114, a silicon oxynitride film with a thickness of 200 nm is used as the insulating film 116, a silicon nitride oxide film with a thickness of 100 nm is used as the insulating film 118, and a silicon oxynitride film with a thickness of 50 nm is used as the insulating film 119, and they are each formed using the PECVD method.

[0259] Also, after forming the insulating films 114, 116, 118, and 119, it is preferable to perform a first heat treatment. By the first heat treatment, a part of the oxygen contained in the insulating films 114 and 116 is moved to the oxide semiconductor film 108, and the amount of oxygen vacancies contained in the oxide semiconductor film 108 can be reduced.

[0260] Next, an oxide semiconductor film 208 is formed on the insulating film 119 (see FIGS. 22(A) and (B)).

[0261] In this embodiment, an In-Ga-Zn metal oxide target (In:Ga:Zn = 4: 2:4.1 [atomic ratio]) is used to form an oxide semiconductor film by sputtering. ​​​​​​​​​​。 Also, the substrate temperature during the formation of the oxide semiconductor film is set to 170 °C, and as the film-forming gas during the formation , oxygen gas with a flow rate of 60 sccm and argon gas with a flow rate of 140 sccm are used 。 After that, by processing the oxide semiconductor film into a desired shape, island-shaped oxide semiconductor film 2 08 is formed. Note that a wet etching apparatus is used for the formation of the oxide semiconductor film.

[0262] Next, a laminated film of an insulating film and a conductive film is formed on the insulating film 119 and the oxide semiconductor film 208 。 After that, by processing the laminated film into a desired shape, island-shaped insulating films 210a, 21 0b and island-shaped conductive films 212a, 212b are formed. After that, insulating films 214, 216 are formed on the insulating film 119, the oxide semiconductor film 208, and the conductive films 212a, 212b ( see FIGS. 23(A)(B)).

[0263] In this embodiment, as the insulating films 210a, 210b, a silicon oxynitride film with a thickness of 50 nm is formed using a PECVD apparatus. Also, as the conductive films 212a, 212b , an oxide semiconductor film with a thickness of 200 nm is formed using a sputtering apparatus. Note that for the oxide semiconductor film, the same composition as that of the oxide semiconductor film 208 is used. Also, as the insulating film 2 14, a silicon nitride film with a thickness of 100 nm is formed using a PECVD apparatus. Also, as the insulating film 216, a silicon oxynitride film with a thickness of 200 nm is formed using a PECVD apparatus 。 。

[0264] Also, a part of the region of the oxide semiconductor film 208 and the conductive films 212a, 212b are in contact with the insulating film 214, and either one or both of hydrogen and nitrogen in the insulating film 214 are added to form an oxide conductor (OC).

[0265] Note that the insulating films 210a and 210b are self-alignedly formed using the conductive films 212a and 212b as masks, respectively.

[0266] Next, openings 282a and 282b that reach the oxide semiconductor film 208 are formed in desired regions of the insulating films 214 and 216 (see FIGS. 24(A) and (B)).

[0267] For the formation of the openings 282a and 282b, a dry etching apparatus or a wet etching apparatus is used.

[0268] Next, a conductive film is formed over the insulating film 216 and the oxide semiconductor film 208 so as to cover the openings 282a and 282b, and the conductive film is processed into an island shape, thereby forming conductive films 218a and 218b (see FIGS. 25(A) and (B)).

[0269] As the conductive films 218a and 218b, a tungsten film with a thickness of 100 nm and a copper film with a thickness of 200 nm are formed by sputtering.

[0270] Next, an insulating film 136 is formed over the insulating film 216 and the conductive films 218a and 218b. Thereafter, by processing a desired region of the insulating film 136, an opening 186 that reaches the conductive film 218b is formed (see FIGS. 26(A) and (B)).

[0271] In this embodiment, as the insulating film 136, a photosensitive acrylic organic resin film with a thickness of 1.5 μm is formed.

[0272] Next, a conductive film is formed over the insulating film 136 and the conductive film 218b, and the conductive film is processed into an island shape, thereby forming a conductive film 138 (see FIGS. 27(A) and (B)).

[0273] ​​​​​​​​​​ In this embodiment, as the conductive film 138, a 10-nm-thick ITSO film, a 200- nm-thick reflective metal film (here, a metal film containing silver, palladium, and copper), and a 1- 0-nm-thick ITSO film are used in a laminated film. Also, for processing the conductive film 138, a wet etching device is used.

[0274] Next, an island-shaped insulating film 140 is formed on the insulating film 136 and the conductive film 138 (see FIGS. 28(A )(B)).

[0275] As the insulating film 140, a 1.5-μm-thick photosensitive polyimide-based organic resin film is used.

[0276] Next, an EL layer 142 is formed on the conductive film 138, and then a conductive film 144 is formed on the insulating film 140 and the EL layer 14 2, thereby forming a light-emitting element 160 (see FIGS. 29(A)(B). ).

[0277] Note that the method for forming the light-emitting element 160 will be described in detail in Embodiment 3.

[0278] Through the above steps, the semiconductor device 200 shown in FIGS. 18(A)(B) can be manufactured.

[0279] Note that the configurations and methods shown in this embodiment can be appropriately combined with the configurations and methods shown in other embodiments and used.

[0280] (Embodiment 3) In this embodiment, a semiconductor device and a method for manufacturing the semiconductor device according to one aspect of the present invention will be described with reference to FIGS. 30 to 45. <…

[0281] <3-1. Configuration Example 1 of Semiconductor Device> Figure 30(A) is a top view of a semiconductor device 300 according to an aspect of the present invention, and Figure 30(B) is , which corresponds to a cross-sectional view of a cut surface between the dashed-dotted lines A1-A2 shown in Figure 30(A). Note that Figure 30(B) includes a cross-section in the channel length (L) direction of the transistor Tr1 and a cross-section in the channel length (L) direction of the transistor Tr2.

[0282] Also, in Figure 30(A), in order to avoid complication, a part of the components of the semiconductor device 300 (such as the insulating film that functions as a gate insulating film) and a part of the reference numerals of the components are omitted and illustrated. Note that in the top view of the semiconductor device, and also in the following drawings, as in Figure 30 (A), there may be cases where a part of the components and a part of the reference numerals of the components are omitted and illustrated. (A), there may be cases where a part of the components and a part of the reference numerals of the components are omitted and illustrated.

[0283] The semiconductor device 300 shown in Figures 30(A) and (B) has a transistor Tr1 and a transistor Tr2, and at least a part of the transistor Tr1 and the transistor Tr2 has a region where they overlap each other. Note that the transistor Tr1 is a transistor with a top gate structure , and the transistor Tr2 is a transistor with a bottom gate structure.

[0284] By providing a region where at least a part of the transistor Tr1 and the transistor Tr2 overlap each other, the layout area of the transistors can be reduced.

[0285] The transistor Tr1 has an insulating film 306 on a substrate 302, an oxide semiconductor film 308 on the insulating film 306, an insulating film 310 on the oxide semiconductor film 308, a conductive film 32 0 on the insulating film 310, and an insulating film 314 on the insulating film 306, the oxide semiconductor film 308, and the conductive film 320. Further, the oxide semiconductor film 308 overlaps with the conductive film 320 and is in contact with the insulating film 310 at the channel region 308i, the source region 308s in contact with the insulating film 314, and the drain region 308d in contact with the insulating film 314. It has.

[0286] Further, the transistor Tr1 includes an insulating film 316 on the insulating film 314, and an oxide semiconductor film 308 in the source region 308s through an opening 341a provided in the insulating film 314 and the insulating film 316. electrically connected conductive film 312a, and an oxide semiconductor film 308 in the drain region 308d through an opening 341b provided in the insulating film 314 and the insulating film 316. electrically connected conductive film 312b, and an insulating film 318 on the insulating film 316, the conductive film 312a, and the conductive film 312b. It has. Further, the transistor Tr2 includes a conductive film 312b, an insulating film 318 on the conductive film 312b, an oxide semiconductor film 328 on the insulating film 318, a conductive film 322a on the oxide semiconductor film 328, and a conductive film 322b on the oxide semiconductor film 328. [[ID=ID=18]] an insulating film 324 on the oxide semiconductor film 328, the conductive film 322a, and the conductive film 322b, an insulating film 326 on the insulating film 324, and a conductive film 330 on the insulating film 326. Note that the conductive film 330 is connected to the conductive film 322a through an opening 382 provided in the insulating films 324 and 326.

[0287] Further, as shown in FIGS. 30(A) and 30(B), the oxide semiconductor film 308 and the oxide semiconductor film 3 28 have an overlapping region. As shown in FIGS. 30(A) and 30(B), the channel region formed in the oxide semiconductor film 308 of the transistor Tr1 and the oxide semiconductor film 328 of the transistor Tr2. It has. Note that the conductive film 330 is connected to the conductive film 322a through an opening 382 provided in the insulating films 324 and 326. It is.

[0288] As shown in FIGS. 30(A) and 30(B), the oxide semiconductor film 308 and the oxide semiconductor film 3 28 have an overlapping region. As shown in FIGS. 30(A) and 30(B), the channel region formed in the oxide semiconductor film 308 of the transistor Tr1 and the oxide semiconductor film 328 of the transistor Tr2. It is preferable that the channel regions formed in the oxide semiconductor films 328 do not overlap with each other. .

[0289] When the channel region of the transistor Tr1 and the channel region of the transistor Tr2 overlap with each other, it may affect the other when one of the transistors is operating. To avoid this influence, a configuration in which the distance between the transistor Tr1 and the transistor Tr2 is increased, or a configuration in which a conductive film is provided between the transistor Tr1 and the transistor Tr2, etc. can be mentioned. However, in the case of the former configuration, since the semiconductor device becomes thick, for example, when forming the semiconductor device 300 on a flexible substrate or the like, the bendability or the like may become a problem. Also, in the case of the latter configuration, an increase in the process of forming the conductive film and a problem may occur because the semiconductor device becomes thick as in the case of the former configuration.

[0290] On the other hand, in the semiconductor device 300 according to one aspect of the present invention, the transistor Tr1 and the transistor Tr2 are arranged overlapping each other, and the channel regions of the respective transistors are provided without overlapping. Also, by arranging a part of the oxide semiconductor film in which the channel region is formed so as to overlap, the arrangement area of the transistor can be suitably reduced.

[0291] Also, the oxide semiconductor film 308 and the oxide semiconductor film 328 each have In, M (M is Al, Ga, Y, or Sn), and Zn. For example, as the oxide semiconductor film 308 and the oxide semiconductor film 328, it is preferable that each has a region where the atomic ratio of In is larger than the atomic ratio of M. However, the semiconductor device according to one aspect of the present invention is not limited to this, ​​​​​​​​A configuration having a region where the atomic ratio of In is less than the atomic ratio of M, or the atomic ratio of In may also be a configuration having a region where it is the same as the atomic ratio of M.

[0292] Further, the oxide semiconductor film 308 and the oxide semiconductor film 328 preferably have the same composition or a substantially the same composition. By making the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 the same, it becomes possible to reduce the manufacturing cost. However, the semiconductor device of one aspect of the present invention is not limited to this, and the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 may be different. The oxide semiconductor film 308 and the oxide semiconductor film is preferably the same or substantially the same. By making the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 the same, it becomes possible to reduce the manufacturing cost. However, the semiconductor device of one aspect of the present invention is not limited to this, and the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 may be different. By making the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 the same, it becomes possible to reduce the manufacturing cost. However, the semiconductor device of one aspect of the present invention is not limited to this, and the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 may be different. is not limited to this, and the compositions of the oxide semiconductor film 308 and the oxide semiconductor film 328 may be different.

[0293] Since the oxide semiconductor film 308 and the oxide semiconductor film 328 have a region where the atomic ratio of In is more than the atomic ratio of M, the field-effect mobilities of the transistor Tr1 and the transistor Tr2 can be increased. Specifically, the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 exceeds 10 cm / Vs, and more preferably the field-effect mobility of either one or both of the transistor Tr1 and the transistor Tr2 can exceed 30 cm / Vs. 2 For example, by using the transistor with the high field-effect mobility described above in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow bezel) can be provided. Further, by using the transistor with the high field-effect mobility described above in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, a connection to the display device can be made / Vs. 2

[0294] For example, by using the transistor with the high field-effect mobility described above in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow bezel) can be provided. Further, by using the transistor with the high field-effect mobility described above in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, a connection to the display device can be made For example, by using the transistor with the high field-effect mobility described above in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow bezel) can be provided. Further, by using the transistor with the high field-effect mobility described above in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, a connection to the display device can be made For example, by using the transistor with the high field-effect mobility described above in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow bezel) can be provided. Further, by using the transistor with the high field-effect mobility described above in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, a connection to the display device can be made For example, by using the transistor with the high field-effect mobility described above in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow bezel) can be provided. Further, by using the transistor with the high field-effect mobility described above in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, a connection to the display device can be made For example, by using the transistor with the high field-effect mobility described above in a gate driver that generates a gate signal of a display device, a display device with a narrow frame width (also referred to as a narrow bezel) can be provided. Further, by using the transistor with the high field-effect mobility described above in a source driver (particularly, a demultiplexer connected to the output terminal of the shift register included in the source driver) that supplies a signal from a signal line of a display device, a connection to the display device can be made ​​​A display device with a small number of continuous wirings can be provided. Also, the above-mentioned field-effect mobility A transistor with high performance is used for either one or both of the selection transistor and the drive transistor of the pixel circuit included in the display device, so that a display device with high display quality can be provided. It is possible.

[0295] In addition, the semiconductor device 300 shown in FIGS. 30(A) and (B) can be suitably used for the pixel circuit of the display device. By adopting the arrangement as shown in FIGS. 30(A) and (B), the pixel density of the display device can be increased. For example, even when the pixel density of the display device exceeds 1000 ppi (pixels per inch), or when the pixel density of the display device exceeds 2000 ppi, by adopting the arrangement as shown in FIGS. 30(A) and (B), the aperture ratio of the pixel can be increased. Note that ppi is a unit representing the number of pixels per inch. It is possible. It is possible to increase the aperture ratio of the pixel. Note that ppi is a unit representing the number of pixels per inch.

[0296] <3-2. Pixel Circuit of Display Device> Here, an example of the case where the semiconductor device 300 shown in FIGS. 30(A) and (B) is applied to the pixel circuit of the display device will be described with reference to FIG. 31. Here, an example of the case where the semiconductor device 300 shown in FIGS. 30(A) and (B) is applied to the pixel circuit of the display device will be described with reference to FIG. 31.

[0297] FIG. 31 is a circuit diagram showing an example of the case where the semiconductor device 300 is applied to the pixel circuit of the display device. It is a circuit diagram.

[0298] The semiconductor device 300 shown in FIG. 31 includes a transistor Tr1, a transistor Tr2, a capacitive element Cs1, and a light-emitting element 360. In FIG. 31, an example of a configuration in which two semiconductor devices 300 are adjacent to each other in the column direction is illustrated. The semiconductor device 300 functions as one of the pixels (or also referred to as sub-pixels). Also, regarding the capacitive element Cs1, in FIG. 30, Regarding the capacitive element Cs1, in FIG. 30, Although not shown, for example, it can be formed using the parasitic capacitance between the conductive film 312b of the transistor Tr1 and the conductive film 322b of the transistor Tr2.

[0299] In the circuit diagram shown in FIG. 31, the data line DL_Y - 1 for writing a data signal to a pixel, the data line DL_Y for writing a data signal to an adjacent pixel, the anode line ANODE_X - 1 for supplying a potential to a light emitting element, the anode line ANODE_X for supplying a potential to an adjacent light emitting element, and the scan line GL_X for supplying a scan signal to a pixel are shown.

[0300] One of the source electrode and the drain electrode of the transistor Tr1 is electrically connected to the data line DL_Y - 1. Further, the first gate electrode and the second gate electrode of the transistor Tr1 are electrically connected to the scan line GL_X. The transistor Tr1 has a function of controlling the writing of data of a data signal.

[0301] One of the pair of electrodes of the capacitor element Cs1 is electrically connected to the other of the source electrode and the drain electrode of the transistor Tr1. Also, the other of the pair of electrodes of the capacitor element Cs1 is electrically connected to the second gate electrode (also referred to as a back gate electrode) of the transistor Tr2. The capacitor element Cs1 has a function as a holding capacitor for holding the written data.

[0302] One of the source electrode and the drain electrode of the transistor Tr2 is electrically connected to the anode line ANODE_X - 1.

[0303] One of the pair of electrodes of the light emitting element 360 is the source electrode and the drain electrode of the transistor Tr2. ​​​​​​​​​​​One is electrically connected to the other electrode, and the other is electrically connected to the cathode line CATHODE. One of the pair of electrodes of the light-emitting element 360 is electrically connected to the other of the pair of electrodes of the capacitor element Cs1.

[0304] The above configuration is an example of applying the semiconductor device 300 shown in FIGS. 30(A) and (B) to a pixel of a display device.

[0305] <3-3. Configuration of Semiconductor Device> Once again, the semiconductor device 300 shown in FIGS. 30(A) and (B) will be described. When the semiconductor device 300 shown in FIGS. 30(A) and (B) is applied to a pixel of a display device, for example, the channel length (L) and channel width (W) of the transistor, or the line widths of the wiring and electrodes connected to the transistor, etc. can be made relatively large. For example, compared with the case where the transistor Tr1 and the transistor Tr2 are arranged on the same plane, as shown in FIGS. 30(A) and (B), by arranging at least a part of the transistor Tr1 and the transistor Tr2 overlapping each other, the line width, etc. can be increased, so that the variation in processing dimensions can be reduced.

[0306] Also, for the transistor Tr1 and the transistor Tr2, one or both of the conductive film and the insulating film can be used in common, so that the number of masks or the number of processes can be reduced.

[0307] For example, in the transistor Tr1, the conductive film 320 functions as a gate electrode, the conductive film 312a functions as a source electrode, and the conductive film 312b functions as a drain electrode. Also, in the transistor Tr1, the insulating film 310 functions as a gate insulating film. Also ​​, in transistor Tr2, conductive film 312b functions as the first gate electrode, conductive film 322a functions as the source electrode, conductive film 322b functions as the drain electrode, and conductive film 330 functions as the second gate electrode. Also, in transistor Tr2, insulating film 318 functions as the first gate insulating film, and insulating films 324 and 326 function as the second gate insulating film.

[0308] In this specification and the like, insulating film 310 may be referred to as the first insulating film, insulating film 318 as the second insulating film, and insulating films 324 and 326 as the third insulating film, respectively.

[0309] Also, an insulating film 334 and an insulating film 336 on insulating film 334 are provided on conductive film 330. Further, an opening 384 reaching conductive film 330 is provided in insulating films 334 and 336. Also, a conductive film 338 is provided on insulating film 336. Note that conductive film 338 is connected to conductive film 330 through opening 384.

[0310] Also, an insulating film 340, an EL layer 342, and a conductive film 344 are provided on conductive film 338. Insulating film 340 covers a part of the side end of conductive film 338 and has a function of preventing short - circuit of conductive film 338 between adjacent pixels. Also, EL layer 342 has a function of emitting light. Also, a light - emitting element 360 is formed by conductive film 338, EL layer 342, and conductive film 344. Conductive film 338 functions as one electrode of light - emitting element 360, and conductive film 344 functions as the other electrode of light - emitting element 360.

[0311] Thus, in one aspect of the present invention, a top - gate - structured transistor and a bottom It can be used in combination with a transistor having a gate structure.

[0312] As described above, a semiconductor device according to one aspect of the present invention has a stacked structure of a plurality of transistors, reducing the installation area of the transistors. Also, in a plurality of transistors, by commonly using either one or both of an insulating film and a conductive film, the number of masks or the number of processes can be reduced.

[0313] <3-4. Configuration of Gate Electrode> Also, as shown in FIGS. 30(A) and (B), the transistor Tr2 has two gate electrodes and is configured as such.

[0314] Here, the effects of the configuration having two gate electrodes will be described with reference to FIGS. 30(A) and (B) and FIG. 3 32.

[0315] Note that FIG. 32 corresponds to a cross-sectional view of a cut surface between the dashed-dotted line B1 - B2 shown in FIG. 30(A). Also, FIG. 32 includes a cross-section in the channel width (W) direction of the transistor Tr2. As shown in FIG. 32, the oxide semiconductor film

[0316] 328 is positioned to face the conductive film 312b and the conductive film 330, and is sandwiched between the conductive films that function as two gate electrodes. The lengths of the conductive film 312b and the conductive film 330 in the channel width direction are each longer than the length of the oxide semiconductor film 328 in the channel width direction, and the entire oxide semiconductor film 328 is covered by the conductive film 312b and the conductive film 330 via the insulating films 318, 32 4, 326. In other words, the conductive film 312b and the conductive film 330 have regions located outside the side ends of the oxide semiconductor film 328.

[0317] ​​​​

[0318] With this structure, the oxide semiconductor film 328 included in the transistor Tr2 The transistor can be electrically surrounded by the electric field of the conductive film 312b and the conductive film 330. As in the case of the transistor Tr2, the electric field of the first gate electrode and the second gate electrode causes the channel The device structure of the transistor that electrically surrounds the oxide semiconductor film where the region is formed is called Sur. This can be called a rounded channel (S-channel) structure.

[0319] The transistor Tr2 has an S-channel structure, and therefore has a first gate electrode The conductive film 312b functions as a gate electrode, so that the electric field for inducing the channel can be effectively applied to the oxide semiconductor. Since the voltage can be applied to the conductive film 328, the current driving capability of the transistor Tr2 is improved. Therefore, it is possible to obtain high on-current characteristics. Therefore, it is possible to miniaturize the transistor Tr2. The conductive film 312b functions as a first gate electrode and the conductive film 312c functions as a second gate electrode. Since the conductive film 330 surrounds the electrode 310, the mechanical strength can be increased.

[0320] The transistor Tr2 shown in FIG. 30(B) has a conductive layer that functions as a second gate electrode. The conductive film 330 functions as a source electrode or a drain electrode of the transistor Tr2. 322a, but is not limited to this. The first gate electrode and the second gate electrode may be connected to each other. By providing openings in 318, 324, and 326, conductive layers that function as second gate electrodes are formed. The film 330 is electrically connected to the conductive film 312b that functions as the first gate electrode at the opening. Therefore, the same potential is applied to the conductive film 312b and the conductive film 330.

[0321] <3-5. Components of the semiconductor device> Next, the components included in the semiconductor device of this embodiment will be described in detail.

[0322] [Substrate] There is no major limitation on the material of the substrate 302, etc., but it is necessary to have at least heat resistance enough to withstand subsequent heat treatment. For example, a glass substrate, a ceramic substrate, a quartz substrate, a sapphire substrate, etc. may be used as the substrate 302. Also, a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, an SOI substrate, etc. can be applied, and those with semiconductor elements provided on these substrates may be used as the substrate 302. When using a glass substrate as the substrate 302, large-sized substrates such as the 6th generation (1500 mm × 1850 mm), the 7th generation (1870 mm × 2200 mm), the 8th generation (2200 mm × 2400 mm), the 9th generation (2400 mm × 2800 mm), the 10th generation (2950 mm × 3400 mm), etc. can be used to fabricate a large-sized display device. Furthermore, a flexible substrate may be used as the substrate 302, and the semiconductor device 300 may be directly formed on the flexible substrate. Or, a release layer may be provided between the substrate 302 and the semiconductor device 300. The release layer can be used to separate from the substrate 302 after partially or completely completing the semiconductor device thereon and transfer it to another substrate. At that time, the semiconductor device 300 has heat resistance.

[0323] Also, a flexible substrate may be used as the substrate 302, and the semiconductor device 300 may be directly formed on the flexible substrate. Or, a release layer may be provided between the substrate 302 and the semiconductor device 300. The release layer can be separated from the substrate 302 after partially or completely completing the semiconductor device thereon and used for transfer to another substrate. ​​​​​​​​​It can also be transferred to inferior substrates or flexible substrates.

[0324] [Conductive film] The conductive films 312a, 312b, 320, 322a, and 322b The conductive films 330, 338, and 344 are made of chromium (Cr), copper (Cu) , aluminum (Al), gold (Au), silver (Ag), zinc (Zn), molybdenum (Mo) , tantalum (Ta), titanium (Ti), tungsten (W), manganese (Mn), nickel lum (Ni), iron (Fe), cobalt (Co), a metal element selected therefrom, or an alloy containing the above-mentioned metal element as a component, or an alloy formed by combining the above-mentioned metal elements can be used to form each respectively.

[0325] Also, the conductive films 312a, 312b, 320, 322a, 32 2b, 330, 338, and 344 may be applied with oxide conductors such as oxides having indium and tin, oxides having tungsten and indium, oxides having tungsten, indium, and zinc , oxides having titanium and indium, oxides having titanium, indium, and tin , oxides having indium and zinc, oxides having silicon, indium, and tin , oxides having indium, gallium, and zinc, etc. It is also possible to apply oxide conductors such as oxides having indium and tin, oxides having tungsten and indium, oxides having tungsten, indium, and zinc, oxides having titanium and indium, oxides having titanium, indium, and tin, oxides having indium and zinc, oxides having silicon, indium, and tin, oxides having indium, gallium, and zinc, etc. respectively.

[0326] In particular, the above-mentioned oxide conductors can be preferably used for the conductive films 320 and 330. Here, the oxide conductor will be described. In this specification, etc., the oxide conductor may also be referred to as OC (Oxide Conductor). As the oxide conductor, for example, when oxygen deficiency is formed in an oxide semiconductor and hydrogen is added to the oxygen deficiency, near the conduction band For example, when oxygen deficiency is formed in an oxide semiconductor and hydrogen is added to the oxygen deficiency, near the conduction band A donor level is formed therein. As a result, the oxide semiconductor becomes highly conductive and turns into a conductor. The oxide semiconductor that has become conductive can be referred to as an oxide conductor. Generally, an oxide semiconductor has a large energy gap and thus has translucency to visible light. On the other hand, an oxide conductor is an oxide semiconductor having a donor level near the conduction band. Therefore, an oxide conductor is less affected by absorption due to the donor level and has translucency to visible light similar to that of the oxide semiconductor.

[0327] Also, a Cu-X alloy film (X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti) may be applied to the conductive film 312a, the conductive film 312b, the conductive film 322a, the conductive film 322b, the conductive film 3 30, the conductive film 338, and the conductive film 344. By using the Cu-X alloy film, it can be processed in a wet etching process, so it is possible to suppress the manufacturing cost.

[0328] In particular, the above-mentioned Cu-X alloy film is preferably used for any one or more of the conductive film 312a, the conductive film 312b, the conductive film 322a, the conductive film 322b, and the conductive film 330. As the Cu-X alloy film, a Cu-Mn alloy film is particularly preferable.

[0329] Also, for any one or more of the conductive film 312a, the conductive film 312b, the conductive film 320, the conductive film 322a, the conductive film 32 2b, and the conductive film 330, among the above-mentioned metal elements, in particular, it is preferable to have any one or more selected from aluminum, copper, titanium, tungsten, tantalum, and molybdenum.

[0330] In addition, any one or more of the conductive film 312a, the conductive film 312b, the conductive film 320, the conductive film 322a, the conductive film 32 2b, and the conductive film 330 are preferably formed of a so-called tantalum nitride film containing nitrogen and tantalum. The tantalum nitride film has conductivity and a high barrier property against copper or hydrogen. Further, since the tantalum nitride film emits little hydrogen from itself, it can be most preferably used as a metal film in contact with the oxide semiconductor film 308 or a metal film in the vicinity of the oxide semiconductor film 308.

[0331] [Insulating film][[ID=I5]] As the insulating films 306, 314, 316, 318, 324, 3 26, 334, 336, and 340, an insulating layer containing at least one of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon nitride film, an aluminum oxide film, a hafnium oxide film, a yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film can be used respectively.

[0332] In addition, the insulating film 306 has a function as a blocking film that suppresses oxygen permeation. For example, when any one or more of the insulating film 314, the insulating film 316, the oxide semiconductor film 308, the oxide semiconductor film 328, the insulating film 324, and the insulating film 326 have an excess oxygen region, the insulating film 306 can suppress oxygen permeation.

[0333] Note that as the insulating film in contact with either one or both of the oxide semiconductor film 308 and the oxide semiconductor film 328, an oxide insulating film is preferable, and it is more excessive than the stoichiometric composition ​​​​​​ It is more preferable to have a region containing oxygen (excess oxygen region). In other words, an oxide insulating film having an excess oxygen region is an insulating film capable of releasing oxygen.

[0334] Note that, as the oxide insulating film having the above-described excess oxygen region, for example, it may be formed by forming an insulating film in an oxygen atmosphere, performing heat treatment on the formed insulating film in an oxygen atmosphere, or adding oxygen into the formed insulating film. As a method of adding oxygen into the formed insulating film, plasma treatment is preferable.

[0335] In addition, hafnium oxide may be used for the insulating film that functions as the gate insulating film of the transistors Tr1 and Tr2. When hafnium oxide is used for the insulating film that functions as the gate insulating film, the following effects can be obtained.

[0336] Hafnium oxide has a higher relative dielectric constant than silicon oxide or silicon oxynitride. Therefore, compared with the case where silicon oxide is used, the film thickness of the insulating film can be increased, so that the leakage current due to the tunnel current can be reduced. That is, a transistor with a small off-current can be realized. Furthermore, hafnium oxide having a crystal structure has a higher relative dielectric constant than hafnium oxide having an amorphous structure. Therefore, in order to obtain a transistor with a small off-current, it is preferable to use hafnium oxide having a crystal structure. Examples of the crystal structure include monoclinic system and cubic system. However, one aspect of the present invention is not limited thereto.

[0337] In addition, the insulating film that functions as the gate insulating film of the transistors Tr1 and Tr2 Silicon nitride may be used for the film. When silicon nitride is used for the insulating film that functions as a gate insulating film, the following effects can be obtained. Silicon nitride has a higher relative dielectric constant compared to silicon oxide, and since the film thickness required to obtain the same capacitance as silicon oxide is large, the insulating film can be made thick. Therefore, it is possible to suppress a decrease in the breakdown voltage of the transistors Tr1 and Tr2, and further improve the breakdown voltage to suppress electrostatic breakdown of the transistors Tr1 and Tr2. When silicon nitride is used, the following effects are achieved. Silicon nitride has a higher relative dielectric constant compared to silicon oxide, and since the film thickness required to obtain the same capacitance as silicon oxide is large, the insulating film can be made thick. Therefore, it is possible to suppress a decrease in the breakdown voltage of the transistors Tr1 and Tr2, and further improve the breakdown voltage to suppress electrostatic breakdown of the transistors Tr1 and Tr2. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film

[0338] For the insulating films 310 and 324, silicon oxide, silicon oxynitride, etc. with a thickness of 5 nm or more and 150 nm or less, preferably 5 nm or more and 50 nm or less can be used. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later. Moreover, the insulating films 310, 316, 318, 324, and 326 have a function of supplying oxygen to either one or both of the oxide semiconductor films 308 and 328. That is, the insulating films 310, 316, 318, 324, and 326 contain oxygen. Also, the insulating films 310 and 324 are insulating films that can transmit oxygen. Note that the insulating film 310 also functions as a damage relaxation film for the oxide semiconductor film 308 when forming the conductive film 320 formed later, and the insulating film 324 also functions as a damage relaxation film for the oxide semiconductor film 328 when forming the insulating film 326 formed later.

[0339] Moreover, it is preferable that the insulating films 310 and 324 have a small defect amount. Typically, by ESR measurement, the spin density of the signal appearing at g = 2.001 derived from silicon dangling bonds is preferably 3 × 10 spins / cm or less. This is because the insulating film

[0340] Moreover, it is preferable that the insulating films 310 and 324 have a small defect amount. Typically, by ESR measurement, the spin density of the signal appearing at g = 2.001 derived from silicon dangling bonds is preferably 3 × 10 spins / cm or less. This is because the insulating film Moreover, it is preferable that the insulating films 310 and 324 have a small defect amount. Typically, by ESR measurement, the spin density of the signal appearing at g = 2.001 derived from silicon dangling bonds is preferably 3 × 10 17 spins / cm 3 Moreover, it is preferable that the insulating films 310 and 324 have a small defect amount. Typically, by ESR measurement, the spin density of the signal appearing at g = 2.001 derived from silicon dangling bonds is preferably 3 × 10 If the defect density included in 314 and 324 is high, oxygen binds to the defects, and the oxygen permeation amount in the insulating film 31 4 will decrease.

[0341] Also, the insulating films 310 and 324 can be formed using an oxide insulating film having a low level density caused by nitrogen oxides. Note that the level density caused by the nitrogen oxides may be formed between the energy (Ev_os) of the upper end of the valence band of the oxide semiconductor film and the energy (Ec_os) of the lower end of the conduction band of the oxide semiconductor film. As the oxide insulating film, a silicon oxynitride film with a small amount of nitrogen oxide released, or an aluminum oxynitride film with a small amount of nitrogen oxide released, etc. can be used. The level density caused by the nitrogen oxides may be formed between the energy (Ev_os) of the upper end of the valence band of the oxide semiconductor film and the energy (Ec_os) of the lower end of the conduction band of the oxide semiconductor film. As the oxide insulating film, a silicon oxynitride film with a small amount of nitrogen oxide released, or an aluminum oxynitride film with a small amount of nitrogen oxide released, etc. can be used. The level density caused by the nitrogen oxides may be formed between the energy (Ev_os) of the upper end of the valence band of the oxide semiconductor film and the energy (Ec_os) of the lower end of the conduction band of the oxide semiconductor film. As the oxide insulating film, a silicon oxynitride film with a small amount of nitrogen oxide released, or an aluminum oxynitride film with a small amount of nitrogen oxide released, etc. can be used. As the above oxide insulating film, a silicon oxynitride film with a small amount of nitrogen oxide released, or an aluminum oxynitride film with a small amount of nitrogen oxide released, etc. can be used. As the above oxide insulating film, a silicon oxynitride film with a small amount of nitrogen oxide released, or an aluminum oxynitride film with a small amount of nitrogen oxide released, etc. can be used. As the above oxide insulating film, a silicon oxynitride film with a small amount of nitrogen oxide released, or an aluminum oxynitride film with a small amount of nitrogen oxide released, etc. can be used.

[0342] Note that a silicon oxynitride film with a small amount of nitrogen oxide released has an ammonia release amount larger than the nitrogen oxide release amount in the temperature programmed desorption gas analysis method (TD S), and typically, the ammonia release amount is 1×10 18 cm -3 or more and 5×10 19 cm -3 or less. Note that the above ammonia release amount is the total amount in the range where the temperature of the heat treatment in TDS is 50°C or more and 650°C or less, or 50°C or more and 550°C or less. Also, the above ammonia release amount is the total amount in terms of ammonia molecules in TDS. the above ammonia release amount is the total amount in the range where the temperature of the heat treatment in TDS is 50°C or more and 650°C or less, or 50°C or more and 550°C or less. Also, the above ammonia release amount is the total amount in terms of ammonia molecules in TDS. the above ammonia release amount is the total amount in terms of ammonia molecules in TDS.

[0343] Nitrogen oxides (NO x , where x is greater than 0 and 2 or less, preferably 1 or more and 2 or less), typically NO2 or NO, form levels in the insulating films 310, 324, etc. The levels are located within the energy gap of the oxide semiconductor films 308 and 328. Therefore, nitrogen oxides At the interface between the insulating film 310 and the oxide semiconductor film 308, or at the interface between the insulating film 324 and the oxide semiconductor film 328, when diffusion occurs, the energy level may trap electrons on the insulating film 310, 324 side in some cases. As a result, the trapped electrons remain near the interface between the insulating film 310 and the oxide semiconductor film 3 08, or near the interface between the insulating film 324 and the oxide semiconductor film 328, causing the threshold voltage of the transistor to shift in the positive direction.

[0344] In addition, nitrogen oxides react with ammonia and oxygen during heat treatment. The nitrogen oxides contained in the insulating film 324 react with the ammonia contained in the insulating film 326 during heat treatment, so that the nitrogen oxides contained in the insulating film 324 are reduced. Therefore, electrons are less likely to be trapped at the interface between the insulating film 324 and the oxide semiconductor film 328.

[0345] By using the above oxide insulating film as the insulating films 310, 324, it is possible to reduce the shift of the threshold voltage of the transistor and reduce the variation in the electrical characteristics of the transistor.

[0346] Note that during the heat treatment in the manufacturing process of the transistor, typically heat treatment at 300°C or higher and lower than 350°C, the insulating films 310, 324 exhibit a first signal with a g value of 2.037 or more and 2.039 or less, a second signal with a g value of 2.00 1 or more and 2.003 or less, and a third signal with a g value of 1.964 or more and 1.966 or less in the spectrum obtained by measuring with an ESR of 100 K or less in the insulating films 310, 324. Note that the split widths of the first signal and the second signal, as well as the split widths of the second signal and the third signal, are in the X-band ESR measurement ​​​​is about 5 mT. Also, the total spin density of the first signal with a g-value of 2.037 or more and 2.039 or less, the second signal with a g-value of 2.001 or more and 2.003 or less, and the third signal with a g-value of 1.964 or more and 1.9 66 or less is less than 1×10 spins / cm 18 Typically, it is less than 1×10 3 spins / cm 17 and more than 1×10 3 spins / 18 cm and less than 1×10 3 spins / cm

[0347] In addition, in the ESR spectrum below 100 K, the total spin density of the first signal with a g-value of 2.037 or more and 2.039 or less, the second signal with a g-value of 2.001 or more and 2.003 or less, and the third signal with a g-value of 1.964 or more and 1.9 66 or less corresponds to the total spin density of the signal caused by nitrogen oxides (NO , where x is greater than 0 and less than or equal to 2, preferably 1 or more and 2 or less). Representative examples of nitrogen oxides include nitric oxide, nitrogen dioxide, etc. That is, the smaller the total spin density of the first signal with a g-value of 2.037 or more and 2.039 or less, the second signal with a g-value of 2.00 1 or more and 2.003 or less, and the third signal with a g-value of 1.964 or more and 1.966 or less, the lower the content of nitrogen oxides in the oxide insulating film. x x, x is greater than 0 and less than or equal to 2, preferably 1 or more and 2 or less) caused by the signal of the spin density of the signal corresponding to the total spin density of the signal. Representative examples of nitrogen oxides include nitric oxide, nitrogen dioxide, etc. That is, the smaller the total spin density of the first signal with a g-value of 2.037 or more and 2.039 or less, the second signal with a g-value of 2.00 1 or more and 2.003 or less, and the third signal with a g-value of 1.964 or more and 1.966 or less, the lower the content of nitrogen oxides in the oxide insulating film. That is, the smaller the total spin density of the first signal with a g-value of 2.037 or more and 2.039 or less, the second signal with a g-value of 2.00 1 or more and 2.003 or less, and the third signal with a g-value of 1.964 or more and 1.966 or less, the lower the content of nitrogen oxides in the oxide insulating film. That is, the smaller the total spin density of the first signal with a g-value of 2.037 or more and 2.039 or less, the second signal with a g-value of 2.00 1 or more and 2.003 or less, and the third signal with a g-value of 1.964 or more and 1.966 or less, the lower the content of nitrogen oxides in the oxide insulating film.

[0348] In addition, the nitrogen concentration measured by SIMS in the oxide insulating film is 6×10 20 atoms / cm 3 or less.

[0349] The substrate temperature is 220°C or more and 350°C or less, and PEC using silane and dinitrogen monoxide is used. By forming the oxide insulating film using the VD method, a dense and hard film can be formed.

[0350] The insulating film 314 has at least one of nitrogen or hydrogen. As the insulating film 314, for example, a nitride insulating film can be mentioned. As the nitride insulating film, for example, silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, etc. can be used to form it. The hydrogen concentration contained in the insulating film 314 is 1×10 22 atoms / cm 3 or more, which is preferable. Also, the insulating film 314 is in contact with the source region 308s and the drain region 308d of the oxide semiconductor film 308. Further, the insulating film 314 has a region in contact with the conductive film 320. Therefore, the hydrogen concentration in the source region 308s, drain region 308d in contact with the insulating film 314, and the conductive film 320 increases, and the carrier density of the source region 308s, drain region 308 d, and the conductive film 320 can be increased. Note that the source region 308s , drain region 308d, and conductive film 320 may each have a region where the hydrogen concentration in the film is the same in contact with the insulating film 314.

[0351] The insulating films 316, 318, and 326 are formed using an oxide insulating film containing more oxygen than oxygen satisfying the stoichiometric composition. An oxide insulating film containing more oxygen than oxygen satisfying the stoichiometric composition releases a part of oxygen by heating. An oxide insulating film containing more oxygen than oxygen satisfying the stoichiometric composition has an oxygen release amount in terms of oxygen molecules of 1 .0×10 cm 19 or more, preferably 3.0×10 -3 cm 20 or more in TDS.-3 The above is the case. Note that the above oxygen release amount is the total amount in the range where the heat treatment temperature in TDS is 50°C or higher and 650°C or lower, and is also the total amount in the range of 50°C or higher and 550°C or lower. Further, the above oxygen release amount is the total amount in terms of oxygen molecules in TDS .

[0352] As the insulating films 316, 318, and 326, silicon oxide, silicon oxynitride, etc. with a thickness of 30 nm or more and 500 nm or less, preferably 50 nm or more and 400 nm or less can be used.

[0353] Also, the insulating films 316, 318, and 326 preferably have a small amount of defects. Typically, by ESR measurement, the spin density of the signal appearing at g = 2.001 derived from silicon dangling bonds is 1.5×10 spins / cm 18 spins / cm 3 less than, and further preferably 1×10 18 s pins / cm 3 or less.

[0354] Also, since the insulating film 324 and the insulating film 326 can use insulating films of the same material, there may be a case where the interface between the insulating film 324 and the insulating film 326 cannot be clearly confirmed. Therefore, in this embodiment, the interface between the insulating film 324 and the insulating film 326 is illustrated by a broken line.

[0355] The insulating film 334 has a function as a protective insulating film for the transistor Tr1 and the transistor Tr2.

[0356] The insulating film 334 has either one or both of hydrogen and nitrogen. Or, the insulating film 3 334 has nitrogen and silicon. Further, the insulating film 334 has oxygen, hydrogen, water, alkali​ The insulating film 334 has a function of blocking metals, alkaline earth metals, etc. As a result, oxygen is diffused from the oxide semiconductor film 308 and the oxide semiconductor film 328 to the outside, and the insulating film 328 is The oxygen contained in the insulating films 310, 316, 324, and 326 diffuses to the outside, and the oxide This can prevent hydrogen, water, and the like from entering the semiconductor films 308 and 328 .

[0357] The insulating film 334 may be, for example, a nitride insulating film. Examples include silicon nitride, silicon nitride oxide, aluminum nitride, and aluminum nitride oxide. etc.

[0358] [Oxide semiconductor film] The oxide semiconductor film 308 and the oxide semiconductor film 328 are formed using the above-described materials. You can be there.

[0359] When the oxide semiconductor film 308 and the oxide semiconductor film 328 are an In-M-Zn oxide, In -The number of atoms of the metal element in the sputtering target used to deposit the M-Zn oxide film The ratio preferably satisfies In>M. The atomic ratio of elements is In:M:Zn=2:1:3, In:M:Zn=3:1:2, In :M:Zn=4:2:4.1, etc.

[0360] In addition, when the oxide semiconductor film 308 and the oxide semiconductor film 328 are In-M-Zn oxide, The metal elements of the sputtering target used to form the In-M-Zn oxide film The atomic ratio may be a composition that satisfies In≦M. The atomic ratio of group elements is In:M:Zn=1:1:1, In:M:Zn=1:1:1. 2, In:M:Zn=1:3:2, In:M:Zn=1:3:4, In:M:Zn=1: 3:6, etc.

[0361] The oxide semiconductor film 308 and the oxide semiconductor film 328 are each formed of In-M-Zn oxide. In the case of oxides, the sputtering target contains polycrystalline In-M-Zn oxide. It is preferable to use a target containing polycrystalline In-M-Zn oxide. This makes it easier to form the oxide semiconductor films 308 and 328 having crystallinity. The atomic ratio of the oxide semiconductor film 308 to the oxide semiconductor film 328 is The ratio of the number of atoms of the metal elements contained in the sputtering target is plus or minus. For example, the oxide semiconductor film 308 and the oxide semiconductor film 328 have a 40% variation. The atomic ratio of In:Ga:Zn=4:2:4.1 is used as the sputtering target. In this case, the atomic ratio of the oxide semiconductor film 308 to the oxide semiconductor film 328 is In: The Ga:Zn ratio may be approximately 4:2:3.

[0362] The oxide semiconductor film 308 and the oxide semiconductor film 328 have an energy gap of 2e 5 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, The off-current of the starter transistor Tr2 can be reduced.

[0363] The oxide semiconductor film 308 and the oxide semiconductor film 328 each have a thickness of 3 nm or more. 200 nm or less, preferably 3 nm or more and 100 nm or less, and more preferably 3 nm or more and 5 0 nm or less.

[0364] In addition, hydrogen contained in the oxide semiconductor film 308 and the oxide semiconductor film 328 reacts with oxygen bonded to metal atoms to form water, and oxygen vacancies are formed in the lattice from which oxygen has desorbed (or the part from which oxygen has desorbed). When hydrogen enters these oxygen vacancies, carriers, i.e., electrons, may be generated. Also, a part of the hydrogen may bond with oxygen bonded to metal atoms to generate carriers, i.e., electrons. Therefore, a transistor using an oxide semiconductor film containing hydrogen tends to have normally-on characteristics. For this reason, it is preferable that the hydrogen content in the oxide semiconductor film 308 and the oxide semiconductor film 328 be reduced as much as possible. Specifically, in the oxide semiconductor film 308 and the oxide semiconductor film 328, the hydrogen concentration obtained by SIMS analysis is preferably 2×10 atoms / cm or less, more preferably 5×10 atoms / cm or less, still more preferably 1×10 atoms / cm

[0365] or less, preferably 5×10 20 atoms / cm 3 or less, more preferably 1×10 atoms / cm 19 or less, still more preferably 5×10 3 atoms / cm 19 or less, preferably 1×10 3 atoms / cm 18 or less, more preferably 5×10 3 atoms / cm 18 or less, still more preferably 1×1 3 atoms / cm 17 or less, even more preferably 5×10 3 atoms / cm 0 16 atoms / cm 3 or less.

[0366] In addition, if silicon or carbon, which is one of the Group 14 elements, is contained in the oxide semiconductor film 308 and the oxide semiconductor film 328, the oxide semiconductor film 308 and the oxide semiconductor film 32 then... In 8, oxygen deficiency increases and n - type formation occurs. Therefore, the silicon concentration obtained by SIMS analysis in the oxide semiconductor film 308 and the oxide semiconductor film 328 is preferably 2 ×10 18 atoms / cm 3 or less, preferably 2×10 17 atoms / cm 3 or less. Do this. Also, the carbon concentration obtained by SIMS analysis in the oxide semiconductor film 308 and the oxide semiconductor film 328 is preferably 2×10 or less, preferably 2×10 18 atoms / cm 3 or less. 1 7 atoms / cm 3 or less.

[0367] Also, in the oxide semiconductor film 308 and the oxide semiconductor film 328, the concentration of alkali metal or alkaline earth metal obtained by SIMS analysis is preferably 1×10 or less, preferably 2×10 18 atom s / cm 3 or less. Alkali metals 16 and alkaline earth metals may generate carriers when combined with the oxide semiconductor, and the off - current of the transistor 3 may increase. Therefore, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the oxide semiconductor film 308 and the oxide semiconductor film 328. Also, the oxide semiconductor film 308 and the oxide semiconductor film 328 may each have a non - single - crystal structure. The non - single - crystal structure is, for example, CAAC - OS (C Axis Aligned Crystalline Oxide Semiconductor) described later, or a polycrystalline structure

[0368] is also acceptable. d Crystalline Oxide Semiconductor), a polycrystalline structure​ In non-single crystalline structures, the amorphous structure is the most defective. The defect density is high in CAAC-OS, and the defect density is lowest in CAAC-OS.

[0369] The various films such as the conductive film, insulating film, and oxide semiconductor film described above may be formed by sputtering. Plasma Enhanced Chemical Vapor Deposition (PECVD) Chemical Vapor Deposition) method, thermal CVD (Chemical It can be formed by the thermal vapor deposition method. As a VD method, MOCVD (Metal Organic Chemical Vapor Deposition) r Deposition) method or ALD (Atomic Layer Deposition) Examples include the ition method.

[0370] The thermal CVD method is a film formation method that does not use plasma, so defects can occur due to plasma damage. This has the advantage that no further processing is required.

[0371] In the thermal CVD method, the source gas and the oxidizing agent are simultaneously fed into the chamber, and the chamber is then heated to atmospheric pressure. The reaction is carried out under high or low pressure near or on the substrate, and the material is deposited on the substrate to form a film. may be performed.

[0372] In addition, the ALD method uses a chamber with atmospheric or reduced pressure, and raw material gases for the reaction are introduced. The film may be formed using the same.

[0373] Thermal CVD methods such as MOCVD and ALD can be used to form conductive films, insulating films, and oxides in the above-described embodiments. It is possible to form various films such as semiconductor films. For example, an In-Ga-ZnO film can be formed. In the case of this, trimethylindium, trimethylgallium, and dimethylzinc are used. The chemical formula of trimethylindium is In(CH3)3. Also, the trimethylga lium's chemical formula is Ga(CH3)3. Also, the chemical formula of dimethylzinc is Zn(C H3)2. Also, it is not limited to these combinations, and triethylgallium (chemical formula Ga(C2H5)3) can be used instead of trimethylgallium, and diethylzinc (chemical formula Zn(C2H5)2) can be used instead of dimethylzinc.

[0374] For example, when forming a hafnium oxide film by a film-forming apparatus using ALD, a raw material gas obtained by vaporizing a liquid containing a solvent and a hafnium precursor compound (hafnium alkoxide, hafnium amide such as tetrakis(dimethyl amide)hafnium (TDMAH)), and two types of gases, ozone (O3) as an oxidizing agent, are used. The chemical formula of tetrakis(dimethylamide)haf nium is Hf[N(CH3)2]4. Also, as other material liquids, there are tetrakis(ethylmethylamide)hafnium and the like.

[0375] For example, when forming an aluminum oxide film by a film-forming apparatus using ALD, a raw material gas obtained by vaporizing a liquid containing a solvent and an aluminum precursor compound (such as trimethylaluminum (TMA)) and two types of gases, H2O as an oxidizing agent, are used. The chemical formula of trimethyl aluminum is Al(CH3)3. Also, as other material liquids, there are tris( dimethylamide)aluminum, triisobutylaluminum, aluminum tris(2 ,2,6,6-tetramethyl-3,5-heptanedionate), and the like.

[0376] For example, when forming a silicon oxide film using a film-forming apparatus that utilizes ALD, hexachlorodisilane is adsorbed onto the film-forming surface, chlorine contained in the adsorbed material is removed, and radicals of an oxidizing gas (O2, nitrous oxide) are supplied to react with the adsorbed material. chlorodisilane is adsorbed onto the film-forming surface, chlorine contained in the adsorbed material is removed, and radicals of an oxidizing gas (O 2, nitrous oxide) are supplied to react with the adsorbed material.

[0377] For example, when forming a tungsten film using a film-forming apparatus that utilizes ALD, an initial tungsten film is formed using WF6 gas and B2H6 gas, and then a tungsten film is formed using WF6 gas and H2 gas. Note that SiH4 gas may be used instead of B2H6 gas. gas and B2H6 gas are used to form an initial tungsten film, and then a tungsten film is formed using WF6 gas and H2 gas. Note that SiH4 gas may be used instead of B2H6 gas. is used.

[0378] For example, when forming an oxide semiconductor film, such as an In-Ga-ZnO film, using a film-forming apparatus that utilizes ALD, an In-O layer is formed using In(CH3)3 gas and O3 gas, then a GaO layer is formed using Ga(CH3)3 gas and O3 gas, and then a ZnO layer is formed using Zn(CH3)2 gas and O3 gas. Note that the order of these layers is not limited to this example. Also, a mixed compound layer such as an In-Ga-O layer, an In-Zn-O layer, or a Ga-Zn-O layer may be formed using these gases. Note that H2O gas obtained by bubbling with an inert gas such as Ar may be used instead of O3 gas, but it is preferable to use O3 gas that does not contain H. Also, In(C2H5)3 gas may be used instead of In(CH3)3 gas. Also, Ga(C2H5)3 gas may be used instead of Ga(CH3)3 gas. Also, Zn(CH3)2 gas may be used. film, an In-O layer is formed using In(CH3)3 gas and O3 gas , then a GaO layer is formed using Ga(CH3)3 gas and O3 gas, and then a Z nO layer is formed using Zn(CH3)2 gas and O3 gas. Note that the order of these layers is not limited to this example. Also, a mixed compound layer such as an In-Ga-O layer, an In-Zn-O layer, or a Ga-Zn-O layer may be formed using these gases. Note that H2O gas obtained by bubbling with an inert gas such as Ar may be used instead of O3 gas, but it is preferable to use O3 gas that does not contain H. Also, In(C2H5)3 gas may be used instead of In(CH3)3 gas. Also, Ga(C2H5)3 gas may be used instead of Ga(CH3)3 gas. Also, Zn(CH3)2 gas may be used. , Ga-Zn-O layer, etc. may be formed. Note that H2O gas obtained by bubbling with an inert gas such as Ar may be used instead of O3 gas, but it is preferable to use O3 gas that does not contain H. Also, In(C2H5)3 gas may be used instead of In(CH3)3 gas. Also, Ga(C2H5)3 gas may be used instead of Ga(CH3)3 gas. Also, Zn(CH3)2 gas may be used. is bubbled with an inert gas such as Ar, and H2O gas obtained may be used, but it is preferable to use O3 gas that does not contain H. Also, In(C2H5)3 gas may be used instead of In(CH3)3 gas. Also, Ga(C2H5)3 gas may be used instead of Ga(CH3)3 gas. Also, Zn(CH3)2 gas may be used. 3 gas is used. 3 gas may be used instead of In(CH3)3 gas. Also, Ga(C2H5)3 gas may be used instead of Ga(CH3)3 gas. Also, Zn(CH3)2 gas may be used. may be used.

[0379] <3-6. Configuration Example 2 of Semiconductor Device> Next, regarding a modified example of the semiconductor device 300 shown in FIGS. 30(A) and (B), with reference to FIG. 33 Explain.

[0380] FIG. 33 is a cross-sectional view of a modified example of the semiconductor device 300 shown in FIG. 30(B).

[0381] FIG. 33 shows a configuration in which a conductive film 330 that functions as a second gate electrode of the transistor Tr2 included in the semiconductor device 300 and an insulating film 334 on the conductive film 330 are not provided. Further, in FIG. 33, instead of the opening 382 provided in the insulating films 324 and 326 and the opening 384 provided in the insulating films 334 and 336, an opening 383 is provided in the insulating films 324, 326, and 336. Thus, it is preferable because the manufacturing process can be reduced by using one opening.

[0382] <3-7. Configuration Example 3 of Semiconductor Device> Next, a modified example of the semiconductor device 300 shown in FIGS. 30(A) and (B) will be described with reference to FIGS. 34(A) and (B) and FIGS. 35(A) and (B).

[0383] Here, the laminated structure of the oxide semiconductor film will be described.

[0384] FIGS. 34(A) and (B) are cross-sectional views in the channel length (L) direction of the transistor Tr2 included in the semiconductor device 300.

[0385] FIG. 34(A) shows a configuration in which the oxide semiconductor film 328 included in the transistor Tr2 includes an oxide semiconductor film 328a, an oxide semiconductor film 328b on the oxide semiconductor film 328a, and an oxide semiconductor film 328c on the oxide semiconductor film 328b. That is, the oxide semiconductor film has a three-layer laminated structure.

[0386] FIG. 34(B) shows an oxide semiconductor film 328 included in the transistor Tr2, which has a structure including an oxide semiconductor film 328b and an oxide semiconductor film 328c on the oxide semiconductor film 328b, i.e., the oxide semiconductor film has a two-layer stacked structure. That is, the oxide semiconductor film has a two-layer stacked structure. That is, the oxide semiconductor film has a two-layer stacked structure.

[0387] An example of the band structure of the oxide semiconductor film 328 and the insulating film in contact with the oxide semiconductor film 328 is shown in FIGS. 35(A) and 35(B). An example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, and 328c, and the insulating film 324 is shown in FIG. 35(A). FIG. 35(B) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328b and 328c, and the insulating film 324. Note that the band structure shows the energy level (Ec) of the lower end of the conduction band of the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324 for easy understanding.

[0388] FIG. 35(A) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324. FIG. 35(A) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324. FIG. 35(B) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328b and 328c, and the insulating film 324. Note that the band structure shows the energy level (Ec) of the lower end of the conduction band of the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324 for easy understanding. FIG. 35(A) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324. FIG. 35(B) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328b and 328c, and the insulating film 324. Note that the band structure shows the energy level (Ec) of the lower end of the conduction band of the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324 for easy understanding. FIG. 35(A) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324. FIG. 35(B) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328b and 328c, and the insulating film 324. Note that the band structure shows the energy level (Ec) of the lower end of the conduction band of the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324 for easy understanding. FIG. 35(A) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324. FIG. 35(B) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328b and 328c, and the insulating film 324. Note that the band structure shows the energy level (Ec) of the lower end of the conduction band of the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324 for easy understanding. FIG. 35(A) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324. FIG. 35(B) shows an example of the band structure in the film thickness direction of a stacked structure including the insulating film 318, the oxide semiconductor films 328b and 328c, and the insulating film 324. Note that the band structure shows the energy level (Ec) of the lower end of the conduction band of the insulating film 318, the oxide semiconductor films 328a, 328b, 328c, and the insulating film 324 for easy understanding.

[0389] FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c. FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c. FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c. FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c. FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c. FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c. FIG. 35(A) is a band diagram of a configuration in which a silicon oxide film is used as the insulating films 318 and 324, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328a, an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 of metal elements is used as the oxide semiconductor film 328b, and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of In:Ga:Zn = 1:3:2 of metal elements is used as the oxide semiconductor film 328c.

[0390] Further, FIG. 35(B) shows a case where silicon oxide films are used as the insulating film 318 and the insulating film 324 , and an oxide semiconductor film formed using a metal oxide target with an atomic ratio of metal elements of In:Ga:Zn = 4:2:4. 1 is used as the oxide semiconductor film 3 , and a metal oxide film formed using a metal oxide target with an atomic ratio of metal elements of In:Ga:Zn = 1:3:2 is used as the oxide semiconductor film 3 28c. It is a band diagram of a configuration using such films.

[0391] As shown in FIGS. 35(A) and (B), in the oxide semiconductor films 328a, 328b, and 328c , the energy level at the lower end of the conduction band changes smoothly. In other words, it can be said that they are continuously changed or continuously joined. In order to have such a band structure, at the interface between the oxide semiconductor film 328a and the oxide semiconductor film 328b, or at the interface between the oxide semiconductor film 328b and the oxide semiconductor film 328c, it is assumed that there are no impurities that form defect levels such as trap centers or recombination centers.

[0392] In order to form a continuous junction in the oxide semiconductor films 328a, 328b, and 328c, it is necessary to continuously stack each film without exposing them to the atmosphere using a multi-chamber film forming apparatus (sputtering apparatus) equipped with a load lock chamber.

[0393] With the configuration shown in FIGS. 35(A) and (B), the oxide semiconductor film 328b becomes a well (pit), and in the transistor using the above stacking structure, it can be seen that the channel region is formed in the oxide semiconductor film 3 28b.

[0394] Note that by providing the oxide semiconductor films 328a and 328c, the trap levels are reduced in the oxide It can be separated from the semiconductor film 328b.

[0395] In addition, the trap level may be farther from the vacuum level than the energy level (Ec) at the lower end of the conduction band of the oxide semiconductor film 328b that functions as a channel region, and electrons tend to accumulate in the trap level. When electrons accumulate in the trap level, it becomes a negative fixed charge, and the threshold voltage of the transistor shifts in the positive direction. Therefore , it is preferable to configure the trap level to be closer to the vacuum level than the energy level (Ec) at the lower end of the conduction band of the oxide semiconductor film 328b. By doing so, it becomes difficult for electrons to accumulate in the trap level, and it is possible to increase the on-current of the transistor and , the field-effect mobility can be increased.

[0396] In addition, the oxide semiconductor films 328a and 328c have energy levels at the lower end of the conduction band closer to the vacuum level than the oxide semiconductor film 328b. Typically, the difference between the energy level at the lower end of the conduction band of the oxide semiconductor film 328b and the energy levels at the lower end of the conduction band of the oxide semiconductor films 328a and 328c is 0.15 eV or more, or 0.5 eV or more, and 2 eV or less, or 1 eV

[0397] With such a configuration, the oxide semiconductor film 328b becomes the main path of the current and functions as a channel region. In addition, the oxide semiconductor films 328a and 328c are channel regions The oxide semiconductor film 328b is formed by using an oxide semiconductor material containing one or more metal elements. Since the oxide semiconductor film 328a is an oxide semiconductor film, the interface between the oxide semiconductor film 328a and the oxide semiconductor film 328b, Alternatively, interface scattering occurs at the interface between the oxide semiconductor film 328b and the oxide semiconductor film 328c. Therefore, the movement of carriers is not hindered at the interface, and the transistor The field effect mobility of the silicon dioxide increases.

[0398] The oxide semiconductor films 328a and 328c function as part of a channel region. In order to prevent this, a material with sufficiently low conductivity is used. In 328c, the electron affinity (the difference between the vacuum level and the energy level at the bottom of the conduction band) is The energy level of the conduction band minimum is smaller than that of the oxide semiconductor film 328b. A material with a difference (band offset) from the conduction band minimum energy level is used. In order to suppress the difference in threshold voltage depending on the magnitude of the drain voltage, The energy levels of the conduction band minimums of the oxide semiconductor films 328a and 328c are It is preferable to use a material whose energy level is closer to the vacuum level than the energy level of the bottom of the conduction band of b. For example, the energy level of the conduction band minimum of the oxide semiconductor film 328b is , 328c, the difference between the energy level of the bottom of the conduction band is 0.2 eV or more, preferably 0.5 It is preferable that the value is 100 eV or more.

[0399] The oxide semiconductor films 328a and 328c do not contain a spinel crystal structure. It is preferable that the oxide semiconductor films 328a and 328c have a spinel crystal structure. When the spinel type crystal structure is included, the conductive film 322a, 322b is formed at the interface between the spinel type crystal structure and other regions. The constituent elements of 2b may diffuse into the oxide semiconductor film 328b. When the oxide semiconductor films 328a and 328c are CAAC-OS described later, it is preferable that the blocking property of the constituent elements of the conductive films 322a and 322b, for example, the copper element, is enhanced. When the oxide semiconductor films 328a and 328c are CAAC-OS described later, it is preferable that the blocking property of the constituent elements of the conductive films 322a and 322b, for example, the copper element, is enhanced. The constituent elements of 2b, for example, the blocking property of the copper element, is preferably increased.

[0400] The film thicknesses of the oxide semiconductor films 328a and 328c are equal to or greater than a film thickness capable of suppressing the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b, and less than a film thickness capable of suppressing the supply of oxygen from the insulating film 324 to the oxide semiconductor film 328b. For example, when the film thicknesses of the oxide semiconductor films 328a and 328c are 10 nm or more, the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b can be suppressed. Also, when the film thicknesses of the oxide semiconductor films 328a and 328c are 100 nm or less, oxygen can be effectively supplied from the insulating film 324 to the oxide semiconductor film 328b. The film thicknesses of the oxide semiconductor films 328a and 328c are equal to or greater than a film thickness capable of suppressing the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b, and less than a film thickness capable of suppressing the supply of oxygen from the insulating film 324 to the oxide semiconductor film 328b. For example, when the film thicknesses of the oxide semiconductor films 328a and 328c are 10 nm or more, the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b can be suppressed. Also, when the film thicknesses of the oxide semiconductor films 328a and 328c are 100 nm or less, oxygen can be effectively supplied from the insulating film 324 to the oxide semiconductor film 328b. The film thicknesses of the oxide semiconductor films 328a and 328c are equal to or greater than a film thickness capable of suppressing the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b, and less than a film thickness capable of suppressing the supply of oxygen from the insulating film 324 to the oxide semiconductor film 328b. For example, when the film thicknesses of the oxide semiconductor films 328a and 328c are 10 nm or more, the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b can be suppressed. Also, when the film thicknesses of the oxide semiconductor films 328a and 328c are 100 nm or less, oxygen can be effectively supplied from the insulating film 324 to the oxide semiconductor film 328b. For example, when the film thicknesses of the oxide semiconductor films 328a and 328c are 10 nm or more, the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b can be suppressed. For example, when the film thicknesses of the oxide semiconductor films 328a and 328c are 10 nm or more, the diffusion of the constituent elements of the conductive films 322a and 322b into the oxide semiconductor film 328b can be suppressed. Also, when the film thicknesses of the oxide semiconductor films 328a and 328c are 100 nm or less, oxygen can be effectively supplied from the insulating film 324 to the oxide semiconductor film 328b. Also, when the film thicknesses of the oxide semiconductor films 328a and 328c are 100 nm or less, oxygen can be effectively supplied from the insulating film 324 to the oxide semiconductor film 328b.

[0401] When the oxide semiconductor films 328a and 328c are In-M-Zn oxides (M is Al, Ga, Y, or Sn), by having M at a higher atomic ratio than In, the energy gap of the oxide semiconductor films 328a and 328c can be increased and the electron affinity can be decreased. Therefore, in some cases, the difference in electron affinity from the oxide semiconductor film is controllable by the composition of M. Also, since M is a metal element having a strong binding force with oxygen, by having these elements at a higher atomic ratio than In, oxygen deficiency is less likely to occur. When the oxide semiconductor films 328a and 328c are In-M-Zn oxides (M is Al, Ga, Y, or Sn), by having M at a higher atomic ratio than In, the energy gap of the oxide semiconductor films 328a and 328c can be increased and the electron affinity can be decreased. Therefore, in some cases, the difference in electron affinity from the oxide semiconductor film is controllable by the composition of M. Also, since M is a metal element having a strong binding force with oxygen, by having these elements at a higher atomic ratio than In, oxygen deficiency is less likely to occur. When the oxide semiconductor films 328a and 328c are In-M-Zn oxides (M is Al, Ga, Y, or Sn), by having M at a higher atomic ratio than In, the energy gap of the oxide semiconductor films 328a and 328c can be increased and the electron affinity can be decreased. Therefore, in some cases, the difference in electron affinity from the oxide semiconductor film is controllable by the composition of M. Also, since M is a metal element having a strong binding force with oxygen, by having these elements at a higher atomic ratio than In, oxygen deficiency is less likely to occur. When the oxide semiconductor films 328a and 328c are In-M-Zn oxides (M is Al, Ga, Y, or Sn), by having M at a higher atomic ratio than In, the energy gap of the oxide semiconductor films 328a and 328c can be increased and the electron affinity can be decreased. Therefore, in some cases, the difference in electron affinity from the oxide semiconductor film is controllable by the composition of M. Also, since M is a metal element having a strong binding force with oxygen, by having these elements at a higher atomic ratio than In, oxygen deficiency is less likely to occur. When the oxide semiconductor films 328a and 328c are In-M-Zn oxides (M is Al, Ga, Y, or Sn), by having M at a higher atomic ratio than In, the energy gap of the oxide semiconductor films 328a and 328c can be increased and the electron affinity can be decreased. Therefore, in some cases, the difference in electron affinity from the oxide semiconductor film is controllable by the composition of M. Also, since M is a metal element having a strong binding force with oxygen, by having these elements at a higher atomic ratio than In, oxygen deficiency is less likely to occur. When the oxide semiconductor films 328a and 328c are In-M-Zn oxides (M is Al, Ga, Y, or Sn), by having M at a higher atomic ratio than In, the energy gap of the oxide semiconductor films 328a and 328c can be increased and the electron affinity can be decreased. Therefore, in some cases, the difference in electron affinity from the oxide semiconductor film is controllable by the composition of M. Also, since M is a metal element having a strong binding force with oxygen, by having these elements at a higher atomic ratio than In, oxygen deficiency is less likely to occur.

[0402] Also, when the oxide semiconductor films 328a and 328c are In-M-Zn oxides, Zn and The atomic ratio of In and M excluding O is preferably 50 atomic % In. less than 50 atomic %, M is higher than 50 atomic %, and more preferably In is 25 atomic % The oxide semiconductor films 328a and 328c are made to have a conductivity of less than 100 Å and a conductivity of M of more than 75 atomic %. A gallium oxide film may be used as the insulating film.

[0403] In addition, when the oxide semiconductor films 328a, 328b, and 328c are made of In-M-Zn oxide, , compared with the oxide semiconductor film 328b, M contained in the oxide semiconductor films 328a and 328c The atomic ratio of the above atoms is typically larger than that of the above atoms contained in the oxide semiconductor film 328b. The atomic ratio is 1.5 times or more, preferably 2 times or more, and more preferably 3 times or more. .

[0404] In addition, when the oxide semiconductor films 328a, 328b, and 328c are made of In-M-Zn oxide, The oxide semiconductor film 328b is formed by mixing In:M:Zn=x1:y1:z1 [atomic ratio] and oxide semiconductor When the conductor films 328a and 328c have an atomic ratio of In:M:Zn=x2:y2:z2, y2 / x2 is greater than y1 / x1, and preferably y2 / x2 is greater than y1 / x1 by 1. More preferably, y2 / x2 is at least two times larger than y1 / x1, and Preferably, y2 / x2 is three or four times larger than y1 / x1. In the oxide semiconductor film 328b, when y1 is equal to or greater than x1, the oxide semiconductor film 328b It is preferable because it can give stable electrical characteristics to a transistor using y1. When the value is three times or more of 1, the field-effect mobility of the transistor including the oxide semiconductor film 328b is Therefore, it is preferable that y1 is less than three times x1.

[0405] When the oxide semiconductor film 328b is an In-M-Zn oxide, in the target used to form the oxide semiconductor film 328b, if the atomic ratio of the metal elements is In:M:Zn = x1: y1:z1, then x1 / y1 is 1 / 3 or more and 6 or less, and further 1 or more and 6 or less, and 、 z1 / y1 is preferably 1 / 3 or more and 6 or less, and further 1 or more and 6 or less. Note that by setting z1 / y1 to 1 or more and 6 or less, CAA C-OS described later is likely to be formed as the oxide semiconductor film 328b. Representative examples of the atomic ratio of the metal elements in the target include I n:M:Zn = 4:2:4.1, In:M:Zn = 1:1:1.2, In:M:Zn = 3 :1:2, etc.

[0406] Also, when the oxide semiconductor films 328a and 328c are In-M-Zn oxides, in the targets used to form the oxide semiconductor films 328a and 328c, if the atomic ratio of the metal elements is In:M:Zn = x2:y2:z2, then x2 / y2 < x1 / y1, and z2 / y2 is preferably 1 / 3 or more and 6 or less, and further 1 or more and 6 or less. Also, by increasing the atomic ratio of M to In, it is possible to increase the energy gap and decrease the electron affinity of the oxide semiconductor films 328a and 328c. Therefore, it is preferable that 、 y2 / x2 is 3 or more, or 4 or more. Representative examples of the atomic ratio of the metal elements in the target include In:M:Zn = 1:3:2, In:M:Zn = 1:3:4, In:M:Z n = 1:3:5, In:M:Zn = 1:3:6, In:M:Zn = 1:4:2, In:M :Zn = 1:4:4, In:M:Zn = 1:4:5, In:M:Zn = 1:5:5, etc. n = 1:3:5, In:M:Zn = 1:3:6, In:M:Zn = 1:4:2, In:M :Zn = 1:4:4, In:M:Zn = 1:4:5, In:M:Zn = 1:5:5, etc. ​​​​​

[0407] Also, when the oxide semiconductor films 328a and 328c are In-M oxides, by configuring them not to contain divalent metal atoms (e.g., zinc, etc.) as M, oxide semiconductor films 328a and 328c that do not contain a spinel-type crystal structure can be formed. Further, as the oxide semiconductor films 328a and 328c, for example, In-Ga oxide films can be used. As the In-Ga oxide, for example, it can be formed by a sputtering method using an In-Ga metal oxide target (In:Ga = 7 :93). Further, in order to form the oxide semiconductor films 328a and 328c by a sputtering method using DC discharge, when In :M = x:y [atomic ratio], y / (x + y) is preferably 0.96 or less, more preferably 0.95 or less, for example, 0.93. :M = x:y [atomic ratio], y / (x + y) is preferably 0.96 or less, more preferably 0.95 or less, for example, 0.93.

[0408] Note that the atomic ratios of the oxide semiconductor films 328a, 328b, and 328c each include a variation of plus or minus 40% of the above atomic ratio as an error.

[0409] Note that in FIGS. 34(A) and (B), the oxide semiconductor film 328 of the transistor Tr2 is illustrated as a two-layer and three-layer stacked structure, but the oxide semiconductor film 3 08 of the transistor Tr1 may have a similar configuration.

[0410] Thus, as the semiconductor device of the present invention, it may be applied by changing the presence or absence of the second gate electrode or the stacked structure of the oxide semiconductor film. Further, the transistor according to the present embodiment can freely combine each of the above structures.

[0411] <3-8. Method for manufacturing a semiconductor device> Next, a method for manufacturing the semiconductor device 300 according to one aspect of the present invention will be described with reference to FIGS. 36 to 45. This will be described.

[0412] Note that FIGS. 36(A), 37(A), 38(A), 39(A), 40(A), 41(A), 42(A), 43(A), 44(A), and 45(A) are top views for explaining the method for manufacturing the semiconductor device 300, and FIGS. 36(B), 37(B), 38( B), 39(B), 40(B), 41(B), 42(B), 43(B), 4 4(B), and 45(B) are cross-sectional views for explaining the method for manufacturing the semiconductor device 300.

[0413] First, an insulating film 306 is formed on a substrate 302, and an oxide semiconductor film is formed on the insulating film 306. Thereafter, the oxide semiconductor film is processed into an island shape to form an oxide semiconductor film 308 (see FIGS. 36(A) and 36(B)). (See FIGS. 36(A) and 36(B)).

[0414] In this embodiment, a glass substrate can be used as the substrate 302.

[0415] As the insulating film 306, a sputtering method, a CVD method, a vapor deposition method, a pulsed laser deposition ( PLD) method, a printing method, a coating method, or the like can be appropriately used for formation. In this embodiment, as the insulating film 306, a PECVD apparatus is used to form a silicon nitride film with a thickness of 400 nm and a silicon oxynitride film with a thickness of 50 nm.

[0416] Further, after forming the insulating film 306, oxygen may be added to the insulating film 306. As the oxygen added to the insulating film 30 6, there are oxygen radicals, oxygen atoms, oxygen atomic ions, oxygen molecular ions, and the like. Further, as the addition method, an ion doping method, an ion implantation method, a plasma treatment There are methods such as this. Also, after forming a film that suppresses the desorption of oxygen on the insulating film, oxygen may be added to the insulating film 306 through the film.

[0417] As the film that suppresses the desorption of oxygen described above, indium, zinc, gallium, tin, aluminum ium, chromium, tantalum, titanium, molybdenum, nickel, iron, cobalt, tungsten, etc. selected metal elements, alloys containing the above-described metal elements as components, alloys formed by combining the above-described metal elements, metal nitrides having the above-described metal elements, metal oxides having the above-described metal elements, metal oxynitrides having the above-described metal elements, etc., can be formed using conductive materials.

[0418] Also, when adding oxygen by plasma treatment, oxygen is excited by microwaves to generate high-density oxygen plasma, thereby increasing the amount of oxygen added to the insulating film 306.

[0419] The oxide semiconductor film 308 can be formed by a sputtering method, a coating method, a pulsed laser deposition method, a laser ablation method, a thermal CVD method, etc. In addition, for processing the oxide semiconductor film 308, a mask is formed on the oxide semiconductor film by a lithography process and then a part of the oxide semiconductor film is etched using the mask. It can be formed. Also, the element-separated oxide semiconductor film 308 may be directly formed using a printing method.

[0420] When forming the oxide semiconductor film by the sputtering method, a power supply device for generating plasma can be appropriately used, such as an RF power supply device, an AC power supply device, or a DC power supply device. Also , when forming the oxide semiconductor film, the sputtering gas used is appropriately a noble gas (typically argon ), oxygen, or a mixed gas of noble gas and oxygen. In the case of the mixed gas of noble gas and oxygen , it is preferable to increase the gas ratio of oxygen with respect to the noble gas.

[0421] When forming the oxide semiconductor film, for example, when using the sputtering method, the substrate temperature is set to 150°C or higher and 750°C or lower, or 150°C or higher and 450°C or lower, or 200°C or higher and 350°C or lower, and by forming the oxide semiconductor film, the crystallinity can be enhanced , which is preferable.

[0422] In this embodiment, as the oxide semiconductor film 308, a sputtering apparatus is used, and an In-Ga-Zn metal oxide (In:Ga:Zn = 4:2:4.1 [atomic ratio]) is used as the sputtering target to form an oxide semiconductor film with a thickness of 40 nm.

[0423] After forming the oxide semiconductor film 308, heat treatment may be performed to dehydrogenate or dehydrate the oxide semiconductor film 308. The temperature of the heat treatment is typically 150°C or higher and lower than the substrate distortion point, or 250°C or higher and 450°C or lower, or 300°C or higher and 450°C or lower . .

[0424] The heat treatment can be performed in an inert gas atmosphere containing a noble gas such as helium, neon, argon, xenon, krypton, or nitrogen. Alternatively, after heating in an inert gas atmosphere, it may be heated in an oxygen atmosphere. Note that it is preferable that neither hydrogen nor water is contained in the above inert atmosphere and oxygen atmosphere. The treatment time may be 3 minutes or more and 24 hours or less. After heating in an inert gas atmosphere, it may be heated in an oxygen atmosphere. Note that it is preferable that neither hydrogen nor water is contained in the above inert atmosphere and oxygen atmosphere. The treatment time may be 3 minutes or more and 24 hours or less. It is preferable that neither hydrogen nor water is contained in the above inert atmosphere and oxygen atmosphere. The treatment time may be 3 minutes or more and 24 hours or less.

[0425] The heat treatment can be carried out using an electric furnace, an RTA apparatus, etc. By using an RTA apparatus it is possible to perform heat treatment at a temperature equal to or higher than the distortion point of the substrate for a limited time. Therefore, the heating treatment time can be shortened.

[0426] By forming a film while heating the oxide semiconductor film or by performing heat treatment after forming the oxide semiconductor film, in the oxide semiconductor film, the hydrogen concentration obtained by secondary ion mass spectrometry is 5 × 10 atoms / cm 19 or less, or 1 × 10 3 atoms / cm 19 or less 3 , 5 × 10 atoms / cm 18 or less, or 1 × 10 3 atoms / cm 18 or less, 3 or 5 × 10 atoms / cm 17 or less, or 1 × 10 3 atoms / cm 16 or less, 3 and can be made to be 5 × 10

[0427] Next, an insulating film and a conductive film are formed on the insulating film 306 and the oxide semiconductor film 308, and are processed into an island shape to form the insulating film 310 and the conductive film 320 (see FIGS. 37(A) and (B)). .

[0428] As the insulating film 310, a silicon oxide film or a silicon oxynitride film can be formed using the PECVD method . In this case, as the source gas, it is preferable to use a depositable gas containing silicon and an oxidizing gas. Representative examples of the depositable gas containing silicon include silane, disilane, trisilane, silane fluoride, etc. Examples of the oxidizing gas include oxygen, ozone, nitrous oxide, nitrogen dioxide, etc. .

[0429] Also, as the insulating film 310, the flow rate of the oxidizing gas is made more than 20 times and less than 100 times, or 40 times or more and 80 times or less with respect to the flow rate of the depositable gas, and the pressure in the processing chamber is made less than 100 Pa, or 50 Pa or less. By using the PECVD method, a silicon oxynitride film with a small amount of defects can be formed.

[0430] Also, as the insulating film 310, the substrate placed in the evacuated processing chamber of the PECVD apparatus is held at 280 °C or higher and 400 °C or lower, and the raw material gas is introduced into the processing chamber to make the pressure in the processing chamber 20 Pa or higher and 250 Pa or lower, more preferably 100 Pa or higher and 250 Pa or lower. Under the condition of supplying high-frequency power to the electrode provided in the processing chamber, as the insulating film 310, a dense silicon oxide film or silicon oxynitride film can be formed.

[0431] Also, the insulating film 310 may be formed using the plasma CVD method using microwaves. Microwaves refer to the frequency range from 300 MHz to 300 GHz. In microwaves, the electron temperature is low and the electron energy is small. Also, in the supplied power, the ratio used for electron acceleration is small, and it is possible to be used for dissociation and ionization of more molecules, and a plasma with a high density (high-density plasma) can be excited. Therefore, plasma damage to the film surface to be deposited and the deposit is small, and an insulating film 310 with few defects can be formed.

[0432] Also, the insulating film 310 can be formed using the CVD method using an organic silane gas. As the organic silane gas, tetraethyl orthosilicate (TEOS: chemical formula Si(OC2H5)4), ​​​​​​​Tetramethylsilane (TMS: chemical formula Si(CH3)4), tetramethylcyclotetrasiloxane (TMCTS), octamethylcyclotetrasiloxane (OMCTS), hexa methyldisilazane (HMDS), triethoxysilane (SiH(OC2H5)3), tri s(dimethylamino)silane (SiH(N(CH3)2)3) and other silicon-containing compounds can be used. By using the CVD method with an organic silane gas, a highly coating insulating film 310 can be formed. In this embodiment, as the insulating film 310, a plasma-enhanced chemical vapor deposition (PECVD) apparatus is used to form a silicon oxynitride film with a thickness of 150 nm.

[0433] Also, the conductive film 320 is preferably formed of an oxide conductor (OC). During the formation of the conductive film 320, oxygen is added from the conductive film 320 into the insulating film 310. As a method for forming the conductive film 320, a sputtering method is used, and it is preferable to form it in an atmosphere containing oxygen gas. By forming the conductive film 320 in an atmosphere containing oxygen gas during formation, oxygen can be preferably added into the insulating film 310.

[0434] Note that as the conductive film 320, the same material as the oxide semiconductor film 308 described above can be used. In this embodiment, as the conductive film 320, a sputtering apparatus is used, and a conductive film with a thickness of 20 nm is formed using an In-Ga-Zn metal oxide (In:Ga:Zn = 5:1:7

[0435] atomic ratio) as a sputtering ring target. When forming the conductive film 320 in an atmosphere containing oxygen gas, oxygen can be preferably added into the insulating film 310. By forming the conductive film 320 in an atmosphere containing oxygen gas during formation, oxygen can be preferably added into the insulating film 310.

[0436] In addition, as the conductive film 320, the same material as the oxide semiconductor film 308 described above can be used. This is possible.

[0437] In this embodiment, as the conductive film 320, a sputtering apparatus is used, and a conductive film with a thickness of 20 nm is formed using an In-Ga-Zn metal oxide (In:Ga:Zn = 5:1:7 atomic ratio) as a sputtering ring target. Using an In-Ga-Zn metal oxide (In:Ga:Zn = 5:1:7

[0438] In this embodiment, the conductive film 320 and the insulating film 310 are processed using a dry etching method. etching method.

[0439] When processing the conductive film 320 and the insulating film 310, the thickness of the oxide semiconductor film 308 in the region where the conductive film 320 does not overlap may become thin. thickness of the oxide semiconductor film 308 may become thin.

[0440] Next, impurity elements are added onto the insulating film 306, the oxide semiconductor film 308, and the conductive film 320. added.

[0441] Examples of the method for adding impurity elements include ion doping, ion implantation, and plasma treatment methods. In the case of the plasma treatment method, plasma is generated in a gas atmosphere containing the impurity element to be added, and the plasma treatment is performed to add the impurity element. As the apparatus for generating the plasma described above, a dry etching apparatus, an ashing apparatus, a plasma CVD apparatus, a high-density plasma CVD apparatus, or the like can be used. Examples of the method for adding impurity elements include ion doping, ion implantation, and plasma treatment methods. In the case of the plasma treatment method, plasma is generated in a gas atmosphere containing the impurity element to be added, and the plasma treatment is performed to add the impurity element. As the apparatus for generating the plasma described above, a dry etching apparatus, an ashing apparatus, a plasma CVD apparatus, a high-density plasma CVD apparatus, or the like can be used. generated and plasma treatment is performed, whereby impurity elements can be added. As the apparatus for generating the above-described plasma, a dry etching apparatus, an ashing apparatus, a plasma CVD apparatus, a high-density plasma CVD apparatus, or the like can be used. Examples of the apparatus for generating the plasma include a dry etching apparatus, an ashing apparatus, a plasma CVD apparatus, a high-density plasma CVD apparatus, and the like. Examples of the apparatus for generating the plasma include a dry etching apparatus, an ashing apparatus, a plasma CVD apparatus, a high-density plasma CVD apparatus, and the like.

[0442] Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320. Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320. Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320. Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320. Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320. Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320. Note that, as the source gas for the impurity element, one or more of B, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film Note that, as the source gas for the impurity element, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2, and rare gases can be used. Alternatively, one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas can be used. By adding one or more of B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and H2 diluted with a rare gas to the oxide semiconductor film 308 and the conductive film 320, one or more of rare gases, hydrogen, boron, carbon, nitrogen, fluorine, phosphorus, sulfur, and chlorine can be added to the oxide semiconductor film 308 and the conductive film 320.

[0443] Alternatively, after adding a noble gas, one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, and H2 may be added to the oxide semiconductor film 3 08 and the conductive film 320.

[0444] Alternatively, after adding one or more of B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4 , Si2H6, F2, HF, and H2, a noble gas may be added to the oxide semiconductor film 3 08 and the conductive film 320.

[0445] The addition of impurity elements may be controlled by appropriately setting implantation conditions such as the acceleration voltage and the dose amount. For example, when adding argon by ion implantation, the acceleration voltage is 10 kV or more and 100 k V or less, and the dose amount is 1 × 10 13 ions / cm 2 or more and 1 × 10 16 ions / cm 2 or less, for example, 1 × 10 ions / cm 14 ions / cm 2 may be sufficient. Also, when adding phosphorus ions by ion implantation, the acceleration voltage is 30 kV and the dose amount is 1 × 10 ions / cm 13 ion s / cm 2 or more and 5 × 10 16 ions / cm 2 or less, for example, 1 × 10 15 ions / cm 2 may be sufficient.

[0446] Also, in this embodiment, argon is added to the oxide semiconductor film 308 and the conductive film 320 as an impurity element using a doping device. Note that in this embodiment , although an example of a configuration in which argon is added as an impurity element has been illustrated, the present invention is not limited thereto. For example, a configuration in which nitrogen is added may be used. Further, for example, the step of adding an impurity element may not be performed.

[0447] Next, an insulating film 314 is formed on the insulating film 306, the oxide semiconductor film 308, and the conductive film 320. Note that by forming the insulating film 314, the oxide semiconductor film 3 08 in contact with the insulating film 314 becomes the source region 308s and the drain region 308d. Further, the oxide semiconductor film 308 not in contact with the insulating film 314, that is, the oxide semiconductor film 308 in contact with the insulating film 310 becomes the channel region 308i. As a result, an oxide semiconductor film 308 having a channel region 308i, a source region 308s , and a drain region 308d is formed (see FIGS. 38(A) (B)). [[ID=,21]]

[0448] The insulating film 314 can be formed by selecting a material that can be used for the insulating film 314. In the present embodiment, as the insulating film 314, a silicon nitride film having a thickness of 1 00 nm is formed using a PECVD apparatus.

[0449] By using a silicon nitride film as the insulating film 314, either one or both of hydrogen and nitrogen in the silicon nitride film enter the conductive film 3 20, the source region 308s, and the drain region 308d, and the carrier density of the conductive film 320, the source region 308s, and the drain region 308d can be increased.

[0450] Next, an insulating film 316 is formed on the insulating film 314.

[0451] ​As the insulating film 316, it can be formed by selecting a material that can be used for the insulating film 316. In this embodiment, as the insulating film 316, using a PECVD apparatus, a silicon oxynitride film with a thickness of 3 00 nm is formed.

[0452] Next, after forming a mask by lithography at a desired position of the insulating film 316, by etching a part of the insulating film 316 and the insulating film 314, an opening 341a reaching the source region 308s and an opening 341b reaching the drain region 308d are formed (see FIGS. 38 (A) and (B)). (Refer to FIGS. 38(A) and (B).)

[0453] As a method for etching the insulating film 316 and the insulating film 314, a wet etching method and / or a dry etching method can be appropriately used. In this embodiment, using a dry etching method, the insulating film 316 and the insulating film 314 are processed.

[0454] Next, a conductive film is formed on the insulating film 316 so as to cover the openings 341a and 341b. After forming a mask by a lithography process at a desired position, a part of the conductive film is etched to form the conductive films 312a and 312b (see FIGS. 38(A) and (B)). (Refer to FIGS. 38(A) and (B).)

[0455] As the conductive films 312a and 312b, they can be formed by selecting a material that can be used for the conductive films 312a and 312b. In this embodiment, as the conductive films 312a and 312b, using a sputtering apparatus, a laminated film of a titanium film with a thickness of 50 nm, an aluminum film with a thickness of 400 nm, and a titanium film with a thickness of 100 nm is formed.

[0456] As a processing method for the conductive films 312a and 312b, a wet etching method and / or a dry The etching method can be appropriately used. In this embodiment, the dry etching method is used to process the conductive film and form the conductive films 312a and 312b.

[0457] Through the above steps, the transistor Tr1 can be fabricated.

[0458] Note that the films (insulating film, oxide semiconductor film, conductive film, etc.) constituting the transistor Tr1 can be formed by a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD ) method, or an ALD (atomic layer deposition) method. Alternatively, they can be formed by a coating method or a printing method. As the film formation method, the sputtering method and the plasma enhanced chemical vapor deposition (PECVD) method are typical, but a thermal CVD method may also be used. As an example of the thermal CVD method, M OCVD (metalorganic chemical vapor deposition) method can be mentioned.

[0459] In the thermal CVD method, the inside of the chamber is set to atmospheric pressure or reduced pressure, and the source gas and the oxidant are simultaneously sent into the chamber and reacted near or on the substrate to deposit on the substrate to form a film. Thus, since the thermal CVD method is a film formation method that does not generate plasma, it has the advantage that defects are not generated due to plasma damage.

[0460] Also, in the ALD method, the inside of the chamber is set to atmospheric pressure or reduced pressure, and the source gas for the reaction is introduced into the chamber and reacted, and this is repeated to form a film. An inert gas (such as argon or nitrogen) may be introduced as a carrier gas together with the source gas. For example, two or more types of source gases may be supplied to the chamber in sequence. In that case, a plurality of types of source gases are mixed ... After the reaction of the first source gas, an inert gas is introduced to prevent roughness, and then the second source gas is introduced. Alternatively, instead of introducing the inert gas, the first source gas may be exhausted by vacuum pumping, and then the second source gas may be introduced. The first source gas adsorbs and reacts on the surface of the substrate to form the first layer, and the subsequently introduced second source gas adsorbs and reacts to form the second layer laminated on the first layer, thereby forming a thin film. By repeating this gas introduction sequence multiple times until the desired thickness is achieved, a thin film with excellent step coverage can be formed. The thickness of the thin film can be adjusted by the number of repetitions of gas introduction, enabling precise film thickness control and making it suitable for fabricating fine FETs.

[0461] Thermal CVD methods such as MOCVD can form films such as the conductive films, insulating films, oxide semiconductor films, and metal oxide films described above. For example, when forming an In-Ga-Zn-O film, trimethylindium (In(CH3)3), trimethylgallium (Ga(CH3 )3), and dimethylzinc (Zn(CH3)2) are used. It is not limited to these combinations, and triethylgallium (Ga(C2H5)3) can be used instead of trimethylgallium, and diethylzinc (Zn(C2H5)2) can be used instead of dimethylzinc. For example, when forming a hafnium oxide film using a film forming apparatus that utilizes ALD, a liquid containing a solvent and a hafnium precursor (such as hafnium alkoxide, tetrakis(dimethylamide)hafnium (TDMAH, Hf[N(CH3)2]4),

[0462] or hafnium amides such as tetrakis(ethylmethylamide)hafnium) is vaporized to obtain a source gas, and ozone is used as an oxidizing agent. ​ Two types of gas of (O3) are used.

[0463] For example, when forming an aluminum oxide film by a film forming apparatus using ALD, a raw material gas obtained by vaporizing a liquid containing a solvent and an aluminum precursor (such as trimethylaluminum (TMA, Al(CH3)3)) and two types of gas of H2O as an oxidizing agent are used. As other materials, there are tris(dimethylamide)aluminum, triisobutylaluminum, and aluminum tris(2,2,6,6-tetramethyl-3,5-heptanedionate). etc.) and two types of gas of H2O as an oxidizing agent are used. As other materials, there are tris(dimethylamide)aluminum, triisobutylaluminum, and aluminum tris(2,2,6,6-tetramethyl-3,5-heptanedionate). There are various ones.

[0464] For example, when forming a silicon oxide film by a film forming apparatus using ALD, hexachlorodisilane is adsorbed on the film forming surface, and radicals of an oxidizing gas (O2, nitrous oxide) are supplied to react with the adsorbed substance.

[0465] For example, when forming a tungsten film by a film forming apparatus using ALD, WF6 gas and B2H6 gas are sequentially introduced to form an initial tungsten film, and then a tungsten film is formed using WF6 gas and H2 gas. Note that SiH4 gas may be used instead of B2H6 gas.

[0466] For example, when forming an oxide semiconductor film, such as an In-Ga-Zn-O film, by a film forming apparatus using ALD, an In-O layer is formed using In(CH3)3 gas and O3 gas, then a GaO layer is formed using Ga(CH3)3 gas and O3 gas, and further a ZnO layer is formed using Zn(CH3)2 gas and O3 gas. Note that the order of these layers is not limited to this example. Also, an In-Ga-O layer or an In-Zn-O layer can be formed using these gases. is not limited to this example. Also, an In-Ga-O layer or an In-Zn-O layer can be formed using these gases. ​​​​​​​​​​​, a mixed compound layer such as a Ga-Zn-O layer may be formed. Instead of O3 gas, Ar H2O gas obtained by bubbling water with an inert gas such as etc. may be used, but it is preferable to use O3...

Claims

【Claim 1】 A semiconductor device having a first transistor and a second transistor, wherein the first transistor has a first gate electrode, a first insulating film on the first gate electrode, a first semiconductor film on the first insulating film, a first source electrode on the first semiconductor film, a first drain electrode on the first semiconductor film, a second insulating film on the first semiconductor film, the first source electrode, and the first drain electrode, and a second gate electrode on the second insulating film, wherein the second transistor has the first drain electrode, the second insulating film on the first drain electrode, a second semiconductor film on the second insulating film, a second source electrode on the second semiconductor film, a second drain electrode on the second semiconductor film, a third insulating film on the second semiconductor film, the second source electrode, and the second drain electrode, and a third gate electrode on the third insulating film, and the first semiconductor film and the second semiconductor film have an overlapping region with each other. A semiconductor device.

Images