Indication device

Abstract

To provide a novel semiconductor device using an oxide semiconductor. The present invention provides a planar semiconductor device using an oxide semiconductor, which has a large on-state current. A semiconductor device is provided. The present invention provides an oxide insulating film, an oxide semiconductor film over the oxide insulating film, and a semiconductor film in contact with the oxide semiconductor film. a source electrode and a drain electrode connected to the source electrode and the drain electrode; a gate insulating film between the source electrode and the drain electrode; a gate electrode overlapping the oxide semiconductor film with a gate insulating film interposed therebetween, a first region overlapping the gate electrode, a second region overlapping the gate electrode, a source electrode, and a drain electrode; and a second region that does not contain the impurity element, wherein the first region and the second region have different concentrations of the impurity element; The gate electrode, the source electrode, and the drain electrode contain the same metal element.

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 (thin film transistor) is made using a semiconductor thin film formed on a substrate with an insulating surface. The technology of constructing thin-film transistors (also called thin-film transistors (TFTs)) is attracting attention. It is widely used in electronic devices such as integrated circuits (ICs) and image display devices (display devices). Semiconductor materials, such as silicon, are widely known as semiconductor thin films that can be used in transistors. However, oxide semiconductors are attracting attention as another material.

[0005] For example, amorphous oxides containing In, Zn, Ga, Sn, etc. are used as oxide semiconductors. Patent Document 1 discloses a technique for fabricating a transistor using this method. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-165529 Summary of the Invention [Problem to be solved by the invention]

[0007] As a transistor using an oxide semiconductor film, for example, an inverted staggered type (bottom gate structure) The oxide semiconductor is a planar type (also called a top gate structure) or a planar type (also called a top gate structure). When a transistor using a conductor film is applied to a display device, it is more However, the manufacturing process of the inverted staggered transistor is relatively simple and the manufacturing cost can be reduced. However, as the screen size of display devices increases, High definition image quality of devices (for example, 4k x 2k (horizontal pixel count = 3840 pixels, vertical pixel count = 1000 pixels) Prime number = 2048 pixels) or 8k x 4k (horizontal pixel count = 7680 pixels, vertical pixel count = 7680 pixels) As high-resolution display devices (represented by a 4320 pixel display) advance, inverted staggered transistors In the case of a transistor, there is a parasitic capacitance between the gate electrode and the source electrode and between the gate electrode and the drain electrode. The capacitance increases signal delays and the like, which causes problems such as deterioration of the image quality of the display device. In addition, in the case of an inverted staggered transistor, the transistor Therefore, a planar transistor using an oxide semiconductor film is proposed. For Renner-type transistors, the structure has stable semiconductor characteristics and high reliability. Furthermore, there is a demand for the development of a transistor that can be formed through a simple manufacturing process.

[0008] In view of the above problems, one embodiment of the present invention provides a novel semiconductor device including an oxide semiconductor. In particular, a planar semiconductor device using an oxide semiconductor is provided. To provide a semiconductor device using a conductor with a large on-state current, or to provide an off-state semiconductor using an oxide semiconductor To provide a semiconductor device with a small current, or to provide a semiconductor device with a small area using an oxide semiconductor To provide a semiconductor device using an oxide semiconductor and having stable electrical characteristics. or to provide a highly reliable semiconductor device using an oxide semiconductor, or to provide a novel semiconductor One of the objects is to provide a semiconductor device or a novel display device.

[0009] The above description of the problem does not preclude the existence of other problems. The embodiment does not necessarily have to solve all of these problems. Problems other than those mentioned above can be solved by the specification. It is clear from the description of the specification, etc. that the problems other than those mentioned above cannot be extracted from the description of the specification, etc. It is possible to issue it. [Means for solving the problem]

[0010] One embodiment of the present invention is a method for manufacturing a semiconductor device including an oxide insulating film, an oxide semiconductor film over the oxide insulating film, and a gate insulating film including an oxide semiconductor film. Source and drain electrodes in contact with the body membrane, and gate insulation between the source and drain electrodes a gate electrode overlapping with the oxide semiconductor film via a gate insulating film, The body membrane has a first region overlapping the gate electrode, a second region overlapping the gate electrode, a source electrode, and a drain electrode. and a second region that does not overlap with the first region, and the first region and the second region have an impurity element concentration Unlike the above, the gate electrode, the source electrode, and the drain electrode contain the same metal element. The semiconductor device is characterized by the above.

[0011] Another embodiment of the present invention is a semiconductor device including: an oxide insulating film; an oxide semiconductor film over the oxide insulating film; The source electrode and the drain electrode contacting the oxide semiconductor film, and the insulating film between the source electrode and the drain electrode a gate insulating film and a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween; The oxide semiconductor film has a first region overlapping the gate electrode, a second region overlapping the gate electrode, a source electrode, and a second region overlapping the gate electrode. and a second region that does not overlap with the drain electrode, the first region and the second region being an impurity source. The second region has a different concentration of silicon, and a nitride insulating film is provided in contact with the second region. a semiconductor device characterized in that the source electrode and the drain electrode contain the same metal element. .

[0012] In each of the above structures, it is preferable that the concentration of the impurity element in the second region is higher than that in the first region. In each of the above structures, the impurity element is preferably hydrogen, boron, carbon, nitrogen, or fluorine. It is preferable that the metal is any one selected from the group consisting of aluminum, silicon, phosphorus and chlorine. It's nice.

[0013] In the above structure, the nitride insulating film is preferably a silicon nitride film.

[0014] Another embodiment of the present invention is a semiconductor device including: an oxide insulating film; an oxide semiconductor film over the oxide insulating film; The source electrode and the drain electrode contacting the oxide semiconductor film, and the insulating film between the source electrode and the drain electrode a gate insulating film and a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween; The oxide semiconductor film has a first region overlapping the gate electrode, a second region overlapping the gate electrode, a source electrode, and a second region overlapping the gate electrode. and a second region that does not overlap with the drain electrode, the second region having a higher hydrogen concentration than the first region. The gate electrode, the source electrode, and the drain electrode contain the same metal element. The semiconductor device is characterized by the above.

[0015] Another embodiment of the present invention is a semiconductor device including: an oxide insulating film; an oxide semiconductor film over the oxide insulating film; The source electrode and the drain electrode contacting the oxide semiconductor film, and the insulating film between the source electrode and the drain electrode a gate insulating film and a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween; The oxide semiconductor film has a first region overlapping the gate electrode, a second region overlapping the gate electrode, a source electrode, and a second region overlapping the gate electrode. and a second region that does not overlap the drain electrode, the first region being more crystalline than the second region. The gate electrode, the source electrode, and the drain electrode are characterized by containing the same metal element. This is a semiconductor device characterized by the above.

[0016] In each of the above structures, the gate electrode, the source electrode, and the drain electrode are at least It is preferable that the portions are formed on the same plane.

[0017] In each of the above structures, the oxide semiconductor film is an In-M-Zn oxide (M is Mg, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf) In each of the above structures, the oxide semiconductor film includes a crystalline portion, and the c-axis of the crystalline portion is an oxide It is preferable that the direction be parallel to the normal vector of the surface on which the semiconductor film is to be formed.

[0018] Another embodiment of the present invention is a semiconductor device using any one of the above structures. It is a display device. [Effects of the Invention]

[0019] According to one embodiment of the present invention, a novel semiconductor device including an oxide semiconductor can be provided. In particular, a planar semiconductor device using an oxide semiconductor can be provided. Alternatively, a semiconductor device including an oxide semiconductor and having a large on-state current can be provided. A semiconductor device using an oxide semiconductor and having a small off-state current can be provided. A semiconductor device using an oxide semiconductor and occupying a small area can be provided. A semiconductor device using an oxide semiconductor and having stable electrical characteristics can be provided. In this way, a highly reliable semiconductor device using an oxide semiconductor can be provided. A novel semiconductor device can be provided. Alternatively, a novel display device can be provided. .

[0020] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. The above will be made clear from the description, drawings, claims, etc. It is possible to extract other effects from the descriptions in the aspects and claims. [Brief explanation of the drawings]

[0021] [Figure 1] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 2] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 3] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 4] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 5] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 6] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 7] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 8] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 9] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 10] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 11] FIG. 1 is a diagram showing an example of a band structure. [Figure 12] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 13] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 14] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 15] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 16] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 17] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 18] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 19] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 20] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 21] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 22] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 23] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 24] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 25] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 26] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 27] FIG. 1 is a top view illustrating one embodiment of a display device. [Figure 28] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 29] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 30] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 31] 1A and 1B are a block diagram and a circuit diagram illustrating a display device. [Figure 32] FIG. 2 is a diagram illustrating a display module. [Figure 33] 1A to 1C illustrate electronic devices. [Figure 34] Cs-corrected high-resolution TEM image of a cross section of CAAC-OS, and a schematic cross-sectional diagram of CAAC-OS. [Figure 35] Cs-corrected high-resolution TEM image of the CAAC-OS in the plane. [Figure 36] 10A and 10B illustrate structural analyses of a CAAC-OS and a single-crystal oxide semiconductor by XRD. [Figure 37] 1A and 1B are a top view and a cross-sectional view showing an example of a connection portion. [Figure 38] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 39] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 40] 1A and 1B are a top view and a cross-sectional view showing an example of a connection portion. [Figure 41] FIG. 10 is a diagram illustrating the temperature dependence of resistivity. [Figure 42] Electron diffraction pattern of CAAC-OS. [Figure 43] FIG. 1 shows the change in the crystalline part of an In-Ga-Zn oxide due to electron irradiation. [Figure 44] Schematic diagram illustrating the film formation model of CAAC-OS and nc-OS. [Figure 45] A diagram explaining InGaZnO4 crystals and pellets. [Figure 46] Schematic diagram illustrating a film formation model of CAAC-OS. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments will be described with reference to the drawings. It is possible to implement the present invention in various ways without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications may be made to the details of the present invention. However, the present invention should not be construed as being limited to the description of the following embodiments.

[0023] Also, in the drawings, the size, thickness of layers, or areas are exaggerated for clarity. Therefore, the scale is not necessarily limited to that shown. The drawings are merely schematic illustrations and are not limited to the shapes or values ​​shown in the drawings.

[0024] In addition, the ordinal numbers "first," "second," and "third" used in this specification refer to the number of components. It should be noted that this is added to avoid confusion and is not intended to limit the number.

[0025] In addition, in this specification, the terms "above" and "below" that indicate the position of components are used to indicate the position of components. The positional relationship is used for convenience in describing the structure with reference to the drawings. The relationship between the two components changes depending on the direction in which each component is depicted. The terms are not limited to those used above, but can be rephrased appropriately depending on the situation.

[0026] In this specification, a transistor includes a gate, a drain, and a source. It is an element having at least three terminals including a drain (drain terminal, drain Between the drain electrode and the source terminal The semiconductor device has a channel region therein, and a current flows through the drain, the channel region, and the source. In this specification and the like, the channel region is a region where a current mainly flows. The flow area.

[0027] The functions of the source and drain may differ depending on whether transistors with different polarities are used or whether the circuit This may happen when the direction of the current changes during operation. In the specification, the terms source and drain may be used interchangeably. do.

[0028] In addition, in this specification, "electrically connected" means "something that has some kind of electrical effect." This includes cases where the device is connected via a "of" is not subject to any particular restrictions as long as it allows the transmission and reception of electrical signals between connected objects. For example, "things that have some kind of electrical action" include electrodes, wiring, and transistors. It has various functions such as switching elements, resistors, inductors, capacitors, etc. This includes elements such as:

[0029] (Embodiment 1) In this embodiment mode, one mode of a semiconductor device and a manufacturing method of the semiconductor device will be described with reference to FIGS. This will be explained using:

[0030] <Configuration 1 of semiconductor device> FIG. 1 shows a top-gate transistor as an example of a transistor included in a semiconductor device. Indicates a register.

[0031] 1A to 1C are top views and cross-sectional views of a transistor 150 included in a semiconductor device. 1A is a top view of the transistor 150, and FIG. 1B is a side view of the transistor 150. 1(A) and FIG. 1(C) is a cross-sectional view taken along the dashed line X1-Y2 in FIG. 1A is a cross-sectional view of the substrate 102 and the insulating film 10 4, insulating film 108, insulating film 116, insulating film 118, etc. are omitted. In the top view of the transistor, the components are shown in the same manner as transistor 150 in the subsequent figures. In some cases, some parts are omitted in the illustration. The direction of the dashed dotted line X1-X2 is the channel length direction, The direction of the dashed dotted line Y1-Y2 may be referred to as the channel width direction.

[0032] The transistor 150 shown in FIG. 1 is an oxide film on an insulating film 104 formed on a substrate 102. A semiconductor film 106, an insulating film 108 in contact with the oxide semiconductor film 106, and an opening in the insulating film 108 The conductive film 110 in contact with the oxide semiconductor film 106 in part of the portion 140a and the insulating film 108 The conductive film 112 is in contact with the oxide semiconductor film 106 in part of the opening 140b. The conductive film 114 overlaps with the oxide semiconductor film 106 with the oxide semiconductor film 108 interposed therebetween. The transistor 150 has an insulating film 116 and an insulating film 118 provided thereon. This is the configuration that can be used.

[0033] In the oxide semiconductor film 106, the conductive film 110, the conductive film 112, and the conductive film 114 overlap. The region where oxygen vacancies do not occur contains elements that form oxygen vacancies. Typical examples of impurity elements include hydrogen, boron, carbon, and nitrogen. fluorine, aluminum, silicon, phosphorus, chlorine, and rare gas elements. Examples include helium, neon, argon, krypton, and xenon.

[0034] When an impurity element is added to an oxide semiconductor film, the metal element and oxygen in the oxide semiconductor film are The bond is broken, and oxygen vacancies are formed. Alternatively, an impurity element is added to the oxide semiconductor film. When the oxide semiconductor film is heated, oxygen that has been bonded to a metal element in the oxide semiconductor film is bonded to an impurity element, and the metal element is As a result, oxygen is released from the element, and oxygen vacancies are formed in the oxide semiconductor film. The carrier density increases, resulting in higher conductivity.

[0035] In addition, when hydrogen is added to an oxide semiconductor in which oxygen vacancies are formed by adding an impurity element, Hydrogen enters the oxygen vacancy site and a donor level is formed near the conduction band. The conductivity of the semiconductor increases and it becomes a conductor. The oxide semiconductor that has become a conductor is called an oxide conductor. Generally, oxide semiconductors have a large energy gap, On the other hand, oxide conductors have donor levels near the conduction band. Therefore, the influence of absorption due to the donor level is small, and the The transparent film has light-transmitting properties comparable to those of an oxide semiconductor.

[0036] Here, the resistance in a film formed of an oxide conductor (hereinafter referred to as an oxide conductor film) The temperature dependency of resistivity will be explained with reference to FIG.

[0037] Here, a sample having an oxide conductor film was fabricated. The oxide conductor film (OC_SiN) formed by the semiconductor film contacting the silicon nitride film x ) In the doping device, argon is added to the oxide semiconductor film, and the silicon nitride film is The oxide conductive film (OC_Ar doped + SiN x ), or In the plasma processing device, the oxide semiconductor film is exposed to argon plasma and silicon nitride is The oxide conductive film formed by contacting with the film (OC_Ar plasma + SiN x )of The silicon nitride film contains hydrogen.

[0038] Oxide conductor film (OC_SiN x The method for preparing a sample containing the SiO2 film is as follows: After forming a silicon oxynitride film with a thickness of 400 nm by plasma CVD, By exposing the silicon oxynitride film to plasma and adding oxygen ions to it, oxygen is released by heating. Next, a silicon oxynitride film that releases oxygen when heated was formed. A sputtering target with an atomic ratio of In:Ga:Zn=1:1:1.2 was placed on the silicon film. A 100 nm thick In-Ga-Zn oxide film was formed by sputtering using After heat treatment in a nitrogen atmosphere at 450°C, the specimen was heated in a nitrogen and oxygen mixed gas atmosphere at 450°C. Next, a silicon nitride film with a thickness of 100 nm was formed by plasma CVD. Next, the substrate was heat-treated at 350° C. in a mixed gas atmosphere of nitrogen and oxygen.

[0039] Oxide conductor film (OC_Ar doped + SiN x The preparation method of the sample containing A 400 nm thick silicon oxynitride film was formed on a glass substrate by plasma CVD. After the formation, the silicon oxynitride film is exposed to oxygen plasma to add oxygen ions to the film. A silicon oxynitride film that releases oxygen by heating was formed. On the silicon oxynitride film, a sputtering layer with an atomic ratio of In:Ga:Zn=1:1:1.2 was formed. A 100 nm thick In-Ga-Zn oxide film was deposited by sputtering using a ZnO target. After forming a nitride film, it was heat-treated in a nitrogen atmosphere at 450°C, and then heated in a nitrogen and oxygen mixture at 450°C. Next, a doping device was used to dope the In-Ga-Zn oxide film. The film was irradiated with 10 kV of acceleration voltage and 5 × 10 14 / cm 2 of argon was added Next, oxygen vacancies were formed in the In-Ga-Zn oxide film by plasma CVD. Next, a silicon nitride film with a thickness of 0.1 nm was formed. Next, a nitrogen and oxygen mixed gas atmosphere was added at 350°C. It was heat treated.

[0040] Oxide conductor film (OC_Ar plasma + SiN x The sample preparation method including A silicon oxynitride film with a thickness of 400 nm was formed on a glass substrate by plasma CVD. After forming the silicon oxynitride film, it is exposed to oxygen plasma to release oxygen when heated. Next, a silicon oxynitride film with an atomic ratio of I was formed on the silicon oxynitride film, which releases oxygen when heated. Sputtering method using a sputtering target of n:Ga:Zn=1:1:1.2 A 100 nm thick In-Ga-Zn oxide film was formed by this method, and then it was heated at 450°C in a nitrogen atmosphere. After the heat treatment, the plate was heated at 450°C in a mixed gas atmosphere of nitrogen and oxygen. In the Zuma processing device, argon plasma is generated and accelerated argon ions are The oxygen vacancies were created by colliding the Zn-Ga oxide film with the Zn-Ga oxide film. Next, a silicon nitride film with a thickness of 100 nm was formed by annealing in a mixture of nitrogen and oxygen at 350°C. The heat treatment was carried out in a gas atmosphere.

[0041] Next, the resistivity of each sample was measured and the results are shown in Figure 41. Here, the resistivity was measured using a four-terminal In FIG. 41, the horizontal axis indicates the measurement temperature, and the vertical axis indicates the indicates the resistivity. x ) measurement results are indicated by square marks, Oxide conductor film (OC_Ar doped + SiN x The measurement results of oxide conductors are shown by circles. Electrical film (OC_Ar plasma+SiN x ) measurement results are indicated by triangles.

[0042] Although not shown, the oxide semiconductor film that is not in contact with the silicon nitride film has a high resistivity. Therefore, it is considered that the oxide conductor film has a higher resistivity than the oxide semiconductor film. It is clear that it is low.

[0043] As can be seen from FIG. 41, the oxide conductor film (OC_Ar doped+SiN x ) and acid Compound conductor film (OC_Ar plasma+SiN x ) contains oxygen vacancies and hydrogen The resistivity fluctuation is small. Typically, the resistivity fluctuation is small between 80K and 290K. The resistivity fluctuation is less than ±20%. Or, the resistivity fluctuation is less than ±20% between 150K and 250K. The coefficient is less than ±10%. Therefore, it is assumed that the oxide conductor film is By using it as the source and drain regions of a transistor, the oxide conductor film and the source The contact with the conductive film that functions as the electrode and drain electrode is an ohmic contact, and the oxide conductive The contact resistance between the conductive film and the conductive film that functions as the source electrode and the drain electrode can be reduced. In addition, since the resistivity of the oxide conductor has low temperature dependency, the oxide conductor film and the source electrode and drain electrode can be easily formed. The amount of change in contact resistance with the conductive film that functions as the drain electrode is small, resulting in highly reliable transistors. It is possible to create a star.

[0044] Here, an enlarged view of the vicinity of the oxide semiconductor film 106 is shown in FIG. The semiconductor film 106 has a region 106a in contact with the conductive film 110 and the conductive film 112 and a region 106b in contact with the insulating film 11. 6, and regions 106c and 106d that overlap with the insulating film 108. do.

[0045] The region 106a functions as a source region and a drain region. The film 112 is made of tungsten, titanium, aluminum, copper, molybdenum, chromium, or titanium. When the conductive material is formed using a conductive material that easily bonds with oxygen, such as aluminum or an alloy, the oxide Oxygen contained in the semiconductor film is bonded to the conductive material contained in the conductive film 110 and the conductive film 112. In addition, oxygen vacancies are formed in the oxide semiconductor film. 0 and some of the constituent elements of the conductive material that forms the conductive film 112 may be mixed in. As a result, the region 106a in contact with the conductive film 110 and the conductive film 112 has increased conductivity. It functions as a source region and a drain region.

[0046] The region 106b and the region 106c function as low resistance regions. The region 106c contains impurity elements. Note that the region 106b contains more impurities than the region 106c. In addition, when the side surface of the conductive film 114 has a tapered shape, the element concentration in the region 106c is high. A part of the conductive film 114 may overlap with the conductive film 114 .

[0047] The impurity element is a rare gas element, and the oxide semiconductor film 106 is formed by a sputtering method. When the region 106a to the region 106d are formed, each of the regions 106a to 106d contains a rare gas element, and the region 106 The concentration of rare gas elements in regions 106b and 106c is higher than that in regions 106a and 106d. This is because when the oxide semiconductor film 106 is formed by a sputtering method, Since a rare gas is used as a ring gas, the rare gas is contained in the oxide semiconductor film 106; In addition, in the regions 106b and 106c, oxygen vacancies are intentionally formed. This is because the gas is added. The region 106a and the region 106d may be doped with a different rare gas element.

[0048] The impurity element is boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, or In the case of chlorine, the impurity element is contained only in the region 106b and the region 106c. Compared with the regions 106a and 106d, the regions 106b and 106c have more impurity sources. In the region 106b and the region 106c, secondary ion mass spectrometry (SIMS: Secondary Ion Mass Spectrometry) The concentration of impurity elements obtained is 5×10 18 atoms / cm 3 More than 1×10 22 at oms / cm 3 or less, or 1×10 19 atoms / cm 3 More than 1×10 21 atom s / cm 3 or less, or 5 x 10 19 atoms / cm 3 5x10 or more 20 atoms / cm 3 It can be as follows:

[0049] When the impurity element is hydrogen, the region 106b is smaller than the region 106a and the region 106d. The concentration of the impurity element is higher in the regions 106b and 106c. The hydrogen concentration obtained by secondary ion mass spectrometry is 8×10 19 atoms / cm 3 or more, or 1×10 20 atoms / cm 3 or more, or 5 x 10 20 ato ms / cm 3 It can be more than that.

[0050] Since the regions 106b and 106c contain impurity elements, oxygen vacancies increase, and the carrier As a result, the regions 106b and 106c become more conductive and have a lower It acts as a resistance area.

[0051] The impurity elements are hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, It may be the case that one or more of phosphorus or chlorine and one or more of the rare gases are used. In this case, the region 1 In the region 106b and the region 106c, oxygen vacancies formed by the rare gas and added to the region Added hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, or salt By interacting with one or more of the elements, regions 106b and 106c become more conductive. This may be the case.

[0052] The region 106d functions as a channel.

[0053] In the insulating film 108, a region overlapping with the oxide semiconductor film 106 and the conductive film 114 is a gate electrode. The insulating film 108 functions as an insulating film. The region where the insulating film 110 and the conductive film 112 overlap functions as an interlayer insulating film.

[0054] The conductive films 110 and 112 function as a source electrode and a drain electrode. The conductive film 114 functions as a gate electrode.

[0055] The transistor 150 described in this embodiment has a region 106d serving as a channel and Between the region 106a functioning as the source region and the drain region, there is provided a region functioning as a low resistance region. The channel, source region, and drain region have a region 106b and a region 106c that function as a gate. The resistance between the transistor 150 and the gate electrode 151 can be reduced. High field-effect mobility.

[0056] In addition, in the manufacturing process of the transistor 150, the conductive film 11 4, and a conductive film 110 and a conductive film 112 which function as a source electrode and a drain electrode. Therefore, in the transistor 150, the conductive film 114 and the conductive film The conductive film 110 and the conductive film 112 do not overlap with each other, and the conductive film 114 and the conductive film 110 and the conductive film 112 As a result, it is possible to reduce the parasitic capacitance between the substrate 102 and the large-area substrate. When using the conductive film 110, the conductive film 112, and the conductive film 114, the signal delay is reduced. It is possible to do this.

[0057] In the transistor 150, the conductive films 110, 112, and 114 The impurity element is added to the oxide semiconductor film 106 using the mask. The lines can form low resistance areas.

[0058] The other components shown in FIG. 1 will be described in detail below.

[0059] The substrate 102 can be made of various substrates and is not limited to a specific one. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), a SO I substrate, glass substrate, quartz substrate, plastic substrate, metal substrate, stainless steel substrate , Stainless steel foil substrate, Tungsten substrate, Tungsten foil a substrate having a fibrous material, a flexible substrate, a laminated film, a paper containing a fibrous material, or a base film Examples of glass substrates include barium borosilicate glass and aluminophore. silicate glass or soda lime glass. Flexible substrate, lamination film Examples of the film and base material are as follows: For example, polyethylene Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone Plastics such as acrylic are also used. Synthetic resins are also available. Examples include polypropylene, polyester, and polyfluoride. Examples of suitable materials include polyvinyl chloride, polyvinyl chloride, and polyamide. Imide, aramid, epoxy, inorganic vapor deposition film, paper, etc. By manufacturing transistors using substrates, single crystal substrates, or SOI substrates, etc. , small variations in characteristics, size, or shape, high current capability, and small size It is possible to manufacture transistors. Circuits can be constructed using such transistors. This makes it possible to reduce the power consumption of the circuit or to increase the integration density of the circuit.

[0060] In addition, a flexible substrate is used as the substrate 102, and a transistor is formed directly on the flexible substrate. Alternatively, a separation layer may be provided between the substrate 102 and the transistor. After completing a part or all of the semiconductor device thereon, the semiconductor device is separated from the substrate 102 and In this case, the transistor is transferred to a substrate with poor heat resistance or a flexible substrate. It can also be transferred onto a flexible substrate. The above-mentioned release layer may be formed of, for example, a tungsten film and an oxide silicon film. The laminated structure of inorganic film with silicon film, or organic resin film such as polyimide film formed on the substrate The above configuration can be used.

[0061] An example of a substrate on which a transistor is transferred is a substrate on which the above-mentioned transistor is formed. In addition to the substrates that can be used, paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates, Lum substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, linen), synthetic fibers (nylon) , polyurethane, polyester) or regenerated fiber (acetate, cupra, rayon, These substrates include recycled polyester, leather substrates, and rubber substrates. By using this, it is possible to form transistors with good characteristics and low power consumption. It can be used to create devices that are less prone to breakage, heat resistant, lightweight, or thin. .

[0062] The insulating film 104 is formed by using a single layer or a stack of an oxide insulating film or a nitride insulating film. Note that in order to improve the interface characteristics with the oxide semiconductor film 106, In this case, at least a region in contact with the oxide semiconductor film 106 is preferably formed using an oxide insulating film. It is also preferable to use an oxide insulating film that releases oxygen by heating as the insulating film 104. Then, oxygen contained in the insulating film 104 is transferred to the oxide semiconductor film 106 by heat treatment. It is possible.

[0063] The thickness of the insulating film 104 is 50 nm or more, or 100 nm or more and 3000 nm or less, or The thickness of the insulating film 104 can be set to 200 nm or more and 1000 nm or less. This can increase the amount of oxygen released from the insulating film 104 and also increase the The interface state at the interface with the conductor film 106 and the region 106d of the oxide semiconductor film 106 It is possible to reduce the oxygen vacancies contained therein.

[0064] The insulating film 104 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. silicon oxide, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn oxide The above may be used, and the layer may be formed as a single layer or a laminate.

[0065] The oxide semiconductor film 106 is typically formed of an In—Ga oxide, an In—Zn oxide, or an In— M-Zn oxide (M is Mg, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or The oxide semiconductor film 106 is formed of a metal oxide such as Hf. do.

[0066] When the oxide semiconductor film 106 is an In-M-Zn oxide, the atomic ratio of In to M is When the sum of In and M is 100 atomic %, In is 25 atomic % or more, M is less than 75 atomic % or In is 34 atomic % or more and M is 66 atomic % Less than ic%.

[0067] The oxide semiconductor film 106 has an energy gap of 2 eV or more, or 2.5 eV or more. Or it is 3 eV or more.

[0068] The thickness of the oxide semiconductor film 106 is greater than or equal to 3 nm and less than or equal to 200 nm, or greater than or equal to 3 nm and less than or equal to 100 nm. The thickness can be 3 nm or less, or 3 nm to 50 nm.

[0069] When the oxide semiconductor film 106 is an In-M-Zn oxide, the In-M-Zn oxide is deposited. The atomic ratio of the metal elements in the sputtering target used for this purpose is In≧M, Zn≧M. It is preferable that the atomic ratio of the metal elements in such a sputtering target and In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn =2:1:1.5, In:M:Zn=2:1:2.3, In:M:Zn=2:1:3, I Preferably, n:M:Zn=3:1:2 or the like. The numerical ratios are calculated by taking into account the atomic fraction of the metal elements contained in the sputtering target. This includes a variation of plus or minus 40% in numerical ratios.

[0070] In addition, the oxide semiconductor film 106 contains silicon or carbon, which is one of the Group 14 elements. If the oxide semiconductor film 106 is filled with oxygen, oxygen vacancies increase in the oxide semiconductor film 106, causing the oxide semiconductor film 106 to become n-type. Therefore, the oxide semiconductor film 106, particularly the region 106d, has a high concentration of silicon and carbon. The concentration (obtained by secondary ion mass spectrometry) was calculated as 2 × 10 18 atoms / cm 3 Below Below, or 2×10 17 atoms / cm 3 As a result, the transaction The transistor has electrical characteristics in which the threshold voltage is positive (also called normally-off characteristics). do.

[0071] In addition, in the oxide semiconductor film 106, especially in the region 106d, secondary ion mass spectrometry The concentration of alkali metals or alkaline earth metals obtained by the precipitation method is 1 × 10 18 ato ms / cm 3 or less, or 2 x 10 16 atoms / cm 3 The following can be done: When alkaline metals and alkaline earth metals combine with oxide semiconductors, they generate carriers. This may increase the off-state current of the transistor. It is preferable to reduce the concentration of alkali metals or alkaline earth metals in the A transistor has an electrical characteristic in which the threshold voltage is positive (also known as a normally-off characteristic). It has.

[0072] Furthermore, when the oxide semiconductor film 106 contains nitrogen, particularly in the region 106d, This may result in the generation of carrier electrons, increasing the carrier density and resulting in n-type conductivity. A transistor using an oxide semiconductor film containing nitrogen tends to be normally on. Therefore, nitrogen can be formed in the oxide semiconductor film, particularly in the region 106d. For example, nitrogen obtained by secondary ion mass spectrometry is preferably reduced as much as possible. Concentration: 5 x 10 18 atoms / cm 3 It can be the following:

[0073] The impurity elements are reduced in the oxide semiconductor film 106, particularly in the region 106d. As a result, the carrier density of the oxide semiconductor film can be reduced. In the film 106, particularly in the region 106d, the carrier density is set to 1×10 17 pieces / cm 3 or less, or 1×10 15 pieces / cm 3 or less, or 1×10 13 pieces / cm 3 Below, is 1 x 10 11 pieces / cm 3 It can be as follows:

[0074] The oxide semiconductor film 106 is an oxide semiconductor film having a low impurity concentration and a low density of defect states. By using the above, a transistor with better electrical characteristics can be manufactured. Here, a low impurity concentration and a low defect level density (few oxygen vacancies) are referred to as high purity pure silicon. High purity intrinsic or substantially high purity intrinsic oxides In semiconductors, the carrier density can be reduced in some cases because there are few carrier sources. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film has a threshold voltage of 100 V. The electrical characteristics tend to be such that the voltage is positive (also called normally-off characteristics). An oxide semiconductor film that is intrinsic or substantially highly purified and intrinsic has a low density of defect states; The trap level density may also be lower. A certain oxide semiconductor film has a significantly small off-state current and a low voltage ( In the drain voltage range of 1V to 10V, the off-state current is Below the measurement limit of the isa, i.e., 1 × 10 -13 A characteristic of less than A can be obtained. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film has fluctuations in electrical characteristics. This may result in a highly reliable transistor.

[0075] The oxide semiconductor film 106 may have a non-single-crystal structure, for example. For example, CAAC-OS (C Axis Aligned Crystalline Oxide Semiconductor), polycrystalline structure, microcrystalline structure (described later), or Among non-single crystal structures, the amorphous structure has the highest defect level density, C AAC-OS has the lowest defect state density.

[0076] Note that the oxide semiconductor film 106 may have an amorphous structure, a microcrystalline structure, or a polycrystalline structure. The film may be a mixed film having two or more of the following: a CAAC-OS region, a CAAC-OS region, and a single crystal structure region. The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CA In the case of a single-layer structure having two or more regions, either an AC-OS region or a single-crystal structure region The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, and the like. A structure in which two or more of the following are stacked: a CAAC-OS region, a CAAC-OS region, and a single-crystal structure region. There are cases where this happens.

[0077] Note that in the oxide semiconductor film 106, the crystallinity of the region 106b is different from that of the region 106d. In addition, in the oxide semiconductor film 106, the region 106c and the region 106d This is because the crystallinity of the region 106b or the region 106c may differ from that of the region 106a. When the doping occurs, damage occurs in the region 106b or the region 106c, and the crystallinity is reduced. This is because the

[0078] The insulating film 108 is formed by using a single layer or a stack of an oxide insulating film or a nitride insulating film. In order to improve the interface characteristics with the oxide semiconductor film 106, At least a region in contact with the oxide semiconductor film 106 is formed using an oxide insulating film. The insulating film 108 is preferably made of, for example, silicon oxide, silicon oxynitride, or silicon nitride oxide. Silicon, silicon nitride, aluminum oxide, hafnium oxide, gallium oxide or Ga The layer may be formed of a single layer or a multilayer, such as Zn oxide.

[0079] In addition, an insulating film having a blocking effect against oxygen, hydrogen, water, etc. is set as the insulating film 108. This allows oxygen to diffuse from the oxide semiconductor film 106 to the outside and oxygen to flow from the oxide semiconductor film 106 to the outside. It is possible to prevent hydrogen, water, etc. from entering the film 106. Examples of insulating films that have this effect include aluminum oxide, aluminum oxynitride, gallium oxide, Gallium oxide nitride, yttrium oxide, yttrium oxide nitride, hafnium oxide, oxynitride Hafnium oxide, etc.

[0080] The insulating film 108 is made of hafnium silicate (HfSiO x ), nitrogen is added Hafnium silicate (HfSi x O y N z ), nitrogen-doped hafnium aluminate (HfAl x O y N z ), high-k materials such as hafnium oxide and yttrium oxide The use of this material can reduce gate leakage of transistors.

[0081] In addition, by using an oxide insulating film that releases oxygen by heating as the insulating film 108, Oxygen contained in the insulating film 108 is transferred to the oxide semiconductor film 106 by heat treatment. is possible.

[0082] As the insulating film 108, a silicon oxynitride film with few defects can be used. Silicon oxynitride films with few defects are measured at ESR below 100K after heat treatment. The first signal in the spectrum obtained by , the second signal with a g value of 2.001 to 2.003, and the second signal with a g value of 1.964 to 1. A third signal of 0.966 or less is observed. Note that the first and second signals The split width of the first signal and the split width of the third signal are The ESR measurement of this material shows that the g value is approximately 5 mT. 1 signal, a second signal with a g value between 2.001 and 2.003, and a g value between 1. The sum of the spin densities of the third signals between 964 and 1.966 is 1×10 18 spi ns / cm 3 less than 1 × 10 17 spins / cm 3 More than 1×10 18 spins / cm 3 is less than.

[0083] In addition, the g value is between 2.037 and 2.039 in the ESR spectrum below 100K. The first signal has a g value of 2.001 or more and 2.003 or less, and the second signal has a g value of 1 The third signal, between 0.964 and 1.966, is nitrogen oxide (NO x , x is between 0 and 2 This corresponds to a signal caused by a g-value of 2.037 or greater, or 1 or greater but less than 2. a first signal with a g value of 0.039 or less, a second signal with a g value of 2.001 or more and 2.003 or less, The sum of the spin densities of the third signals with g values ​​between 1.964 and 1.966 is small. It can be said that the smaller the content of nitrogen oxides in the silicon oxynitride film, the smaller the content of nitrogen oxides in the silicon oxynitride film.

[0084] In addition, the silicon oxynitride film with few defects has a nitrogen concentration measured by secondary ion mass spectrometry. Degrees are 6 x 10 20 atoms / cm 3 The insulating film 108 is an oxide film with few defects. By using a silicon nitride film, nitrogen oxides are less likely to be generated, and the oxide semiconductor film 1 It is possible to reduce carrier traps at the interface between the silicon dioxide film and the insulating film. It is possible to reduce the shift in threshold voltage of a transistor included in a semiconductor device. This can reduce fluctuations in the electrical characteristics of the transistor.

[0085] The thickness of the insulating film 108 is 5 nm or more and 400 nm or less, or 5 nm or more and 300 nm or less. , or 10 nm or more and 250 nm or less.

[0086] The conductive film 110, the conductive film 112, and the conductive film 114 are formed in the same process, and therefore are made of the same material. The conductive film 110, the conductive film 112, and the conductive film 114 are made of aluminum. Aluminum, Chromium, Copper, Tantalum, Titanium, Molybdenum, Nickel, Iron, Cobalt, Tan or an alloy containing the above-mentioned metal elements, or It can be formed by using an alloy of a combination of metal elements. Alternatively, the conductive film 1 may be formed of one or more metal elements selected from the group consisting of fluorine, fluorine, arsenic ... 10, the conductive film 112 and the conductive film 114 may have a single layer structure or a stacked structure of two or more layers. For example, a single layer structure of an aluminum film containing silicon, a single layer structure of a copper film containing manganese, Two-layer structure: titanium film laminated on aluminum film, titanium film laminated on titanium nitride film Two-layer structure with tungsten film on titanium nitride film, two-layer structure with tantalum nitride film or a two-layer structure in which a tungsten film is laminated on a tungsten nitride film, or a copper film containing manganese A two-layer structure in which a copper film is laminated on top of a titanium film, and an aluminum film is laminated on top of the titanium film. A three-layer structure in which a titanium film is formed on top of that, a copper film is laminated on top of a copper film containing manganese, and There are three-layer structures, such as a copper film containing manganese on top of aluminum. Select from tantalum, tungsten, molybdenum, chromium, neodymium, and scandium. Alternatively, an alloy film or a nitride film made by combining one or more of these may be used.

[0087] The conductive films 110, 112, and 114 are formed of indium tin oxide, oxide Tungsten-containing indium oxide, tungsten oxide-containing indium zinc oxide, Indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium A conductive material having light-transmitting properties, such as zinc oxide or indium tin oxide containing silicon oxide, is used. Also, a laminated structure of the above-mentioned light-transmitting conductive material and the above-mentioned metal element can be used. It can also be done as follows.

[0088] The thickness of the conductive film 110, the conductive film 112, and the conductive film 114 is 30 nm or more and 500 nm or less. or 100 nm or more and 400 nm or less.

[0089] The insulating film 116 is formed by using a single layer or a stack of an oxide insulating film or a nitride insulating film. Note that in order to improve the interface characteristics with the oxide semiconductor film 106, In this case, at least a region in contact with the oxide semiconductor film 106 is preferably formed using an oxide insulating film. It is preferable to use an oxide insulating film that releases oxygen by heating as the insulating film 116. Then, oxygen contained in the insulating film 116 is transferred to the oxide semiconductor film 106 by heat treatment. It is possible.

[0090] The insulating film 116 may be made of, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. silicon oxide, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn oxide The above may be used, and the layer may be formed as a single layer or a laminate.

[0091] The insulating film 118 is preferably a film that functions as a barrier film against hydrogen, water, and the like from the outside. The insulating film 118 may be made of, for example, silicon nitride, silicon nitride oxide, or aluminum oxide. The above may be used, and the layer may be formed as a single layer or a laminate.

[0092] The thickness of the insulating film 116 and the insulating film 118 is 30 nm or more and 500 nm or less, can be 100 nm or more and 400 nm or less.

[0093] <Configuration 2 of semiconductor device> Next, another configuration of the semiconductor device will be described with reference to FIG.

[0094] 3A to 3C are top views and cross-sectional views of a transistor 151 included in a semiconductor device. 3A is a top view of the transistor 151, and FIG. 3B is a top view of the transistor 151. 3(A) and FIG. 3(C) is a cross-sectional view taken along the dashed line X1-Y2 in FIG. Cross-sectional view of section X2.

[0095] The transistor 151 illustrated in FIG. 3 includes the conductive film 110, the conductive film 112, and the conductive film 114. , each of which has a three-layer structure. The insulating film 104a and the oxide insulating film 104b are stacked in layers. It is similar to the transistor 150 and has the same effect.

[0096] First, the conductive films 110, 112, and 114 will be described.

[0097] The conductive film 110 is formed by laminating a conductive film 110a, a conductive film 110b, and a conductive film 110c in this order. The conductive film 110a and the conductive film 110c cover the surface of the conductive film 110b. That is, the conductive film 110a and the conductive film 110c serve as protective films for the conductive film 110b. It works.

[0098] Similar to the conductive film 110, the conductive film 112 includes a conductive film 112a, a conductive film 112b, and a conductive film 112c. The conductive film 112a and the conductive film 112c are laminated in this order, and the conductive film 112a and the conductive film 112c are It covers the surface of 112b.

[0099] Similar to the conductive film 110, the conductive film 114 includes a conductive film 114a, a conductive film 114b, and a conductive film 114c. The conductive film 114a and the conductive film 114c are laminated in this order, and the conductive film 114a and the conductive film 114c are It covers the surface of 114b.

[0100] The conductive film 110a, the conductive film 112a, and the conductive film 114a are 12b, to prevent a metal element contained in the conductive film 114b from diffusing into the oxide semiconductor film 106. The conductive films 110a, 112a, and 114a are formed using the following material: , titanium, tantalum, molybdenum, tungsten, or titanium nitride The insulating layer 10 can be formed using tantalum nitride, molybdenum nitride, tantalum nitride, or the like. The conductive film 110a, the conductive film 112a, and the conductive film 114a are made of a Cu—X alloy (X is M It can be formed using materials such as n, Ni, Cr, Fe, Co, Mo, Ta, or Ti. do.

[0101] In addition, Cu-X alloy (X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti) In the case of the insulating film, a coating film is formed in a region in contact with the oxide semiconductor film or the insulating film by heat treatment. The coating film may be formed from a compound containing X. An example of a compound containing X is Examples include X oxide, In-X oxide, Ga-X oxide, In-Ga-X oxide, and In- The conductive film 110a, the conductive film 112a, and the conductive film 114a include Ga-Zn-X oxides. The coating film formed on the surface acts as a blocking film, preventing the formation of a metal in the Cu-X alloy film. It is possible to prevent Cu from entering the oxide semiconductor film.

[0102] Note that the copper concentration in the region of the oxide semiconductor film 106 that functions as a channel is set to 1×1 0 18 atoms / cm 3 By setting the following, the insulating film 108 functioning as a gate insulating film can be formed. Therefore, the density of electron trap states at the interface between the oxide semiconductor film 106 and the silicon dioxide film 108 can be reduced. As a result, it is possible to fabricate transistors with excellent subthreshold swing values ​​(S values). It is possible.

[0103] The conductive film 110b, the conductive film 112b, and the conductive film 114b are formed using a low-resistance material. The conductive films 110b, 112b, and 114b are made of copper, aluminum, or the like. It can be formed using a single metal or alloy of gold, silver, etc., or a compound containing these as the main component. This can be done.

[0104] The conductive film 110c, the conductive film 112c, and the conductive film 114c are 12b, the conductive film 114b is formed using a film in which the metal elements contained in the conductive film 114b are passivated. The metal elements contained in the conductive films 110b, 112b, and 114b are In this case, the conductive film 6 can be prevented from moving to the oxide semiconductor film 106. The conductive films 110c, 112c, and 114c are made of metal silicide or metal silicide nitride. It can be formed using materials such as CuSi x (x>0), CuSi x N y (x>0, y>0), etc.

[0105] Here, a method for forming the conductive film 110c, the conductive film 112c, and the conductive film 114c will be described. The conductive films 110b, 112b, and 114b are made of copper. The conductive film 110c, the conductive film 112c, and the conductive film 114c are made of CuSi x N y It is formed using (x>0, y>0).

[0106] The conductive films 110b, 112b, and 114b are treated with hydrogen, ammonia, and monoxide. The conductive film 110b, the conductive film 112b, and the conductive film 112c are exposed to plasma generated in a reducing atmosphere such as carbon. Also, oxides on the surface of the conductive film 114b are reduced.

[0107] Next, the conductive film 110b, the conductive film 112b, and the conductive film 112c are heated at a temperature of 200° C. or more and 400° C. or less. and conductive film 114b are exposed to silane. As a result, conductive film 110b, conductive film 112b, and The copper contained in the conductive film 114b acts as a catalyst, and the silane is decomposed into Si and H2. In addition, CuSi is formed on the surfaces of the conductive film 110b, the conductive film 112b, and the conductive film 114b. x (x> 0) is formed.

[0108] Next, the conductive films 110b, 112b, and 114b are treated with ammonia or nitrogen. By exposing the conductive film 110b and the conductive film 110c to plasma generated in an atmosphere containing nitrogen, 12b, and CuSi formed on the surface of the conductive film 114b. x (x>0) is contained in the plasma The conductive film 110c, the conductive film 112c, and the conductive film 114c react with the nitrogen contained in the conductive film 110c, and form Cu. Si x N y (x>0, y>0) is formed.

[0109] In the above process, the conductive film 110b, the conductive film 112b, and the conductive film 114b are After exposure to plasma generated in an atmosphere containing nitrogen, such as ammonia or nitrogen, The conductive film 110b, the conductive film 112b, and the conductive film 114b are heated at a temperature of 400° C. or less. The conductive film 110c, the conductive film 112c, and the conductive film 114c are formed by exposing the conductive film 110c to silane. CuSi x N y (x>0, y>0) may be formed.

[0110] Next, the insulating film 104 in which the nitride insulating film 104a and the oxide insulating film 104b are stacked is and explain.

[0111] For example, the nitride insulating film 104a may be made of silicon nitride, silicon nitride oxide, or aluminum nitride. The oxide insulating film 10 can be formed using aluminum, aluminum nitride oxide, or the like. 4b may be formed using silicon oxide, silicon oxynitride, aluminum oxide, or the like. By providing the nitride insulating film 104a on the substrate 102 side, it is possible to prevent hydrogen and water from entering from the outside. and the like can be prevented from diffusing into the oxide semiconductor film 106.

[0112] <Configuration 3 of semiconductor device> Next, another configuration of the semiconductor device will be described with reference to FIGS.

[0113] 4A to 4C are top views and cross-sectional views of a transistor 152 included in a semiconductor device. 4A is a top view of the transistor 152, and FIG. 4B is a side view of the transistor 152. 4(A) and FIG. 4(C) is a cross-sectional view taken along the dashed line X1-Y2 in FIG. Cross-sectional view of section X2.

[0114] The transistor 152 shown in FIG. 4 is characterized in that the oxide semiconductor film 106 has a multilayer structure. Specifically, the oxide semiconductor film 106 is formed by arranging the oxide semiconductor film 106 in contact with the insulating film 104. 107a, an oxide semiconductor film 107b in contact with the oxide semiconductor film 107a, and an oxide semiconductor film 107b, the oxide film in contact with the conductive film 110, the conductive film 112, the insulating film 108, and the insulating film 116. The other configurations are the same as those of the transistor 150. It has the same effect.

[0115] The oxide semiconductor films 107a, 107b, and 107c are Representative examples include In-Ga oxide, In-Zn oxide, and In-M-Zn oxide (M is Mg , Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf) is formed.

[0116] The oxide semiconductor films 107a and 107c are typically made of In-G a oxide, In-Zn oxide, In-Mg oxide, Zn-Mg oxide, In-M-Zn oxide oxides (M represents Mg, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf) ) and the energy of the conduction band minimum is closer to the vacuum level than that of the oxide semiconductor film 107b. Typically, the energy at the bottom of the conduction band of the oxide semiconductor film 107a and the oxide semiconductor film 107c is the difference between the energy of the oxide semiconductor film 107b and the energy of the bottom of the conduction band of the oxide semiconductor film 107a is 0.05 eV or more. Above, 0.07 eV or more, 0.1 eV or more, or 0.2 eV or more and 2 eV or less, 1 e V or less, 0.5 eV or less, or 0.4 eV or less. The energy difference is also called electron affinity.

[0117] The oxide semiconductor film 107b is an In-M-Zn oxide (wherein M is Mg, Al, Ti, Ga, Y , Zr, La, Ce, Nd, or Hf), the oxide semiconductor film 107b is formed. In the target used for this purpose, the atomic ratio of the metal elements is In:M:Zn=x1:y If we set it to 1:z1, 、 x1 / y1 is equal to or greater than 1 / 3 and equal to or less than 6, and further equal to or greater than 1 and equal to or less than 6, z1 / y1 is preferably 1 / 3 or more and 6 or less, and more preferably 1 or more and 6 or less. When z1 / y1 is greater than or equal to 1 and less than or equal to 6, the oxide semiconductor film 107b can have a CAAC-OS A typical example of the atomic ratio of the target metal elements is In:M :Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:1. 5. In:M:Zn = 2:1:2.3, In:M:Zn = 2:1:3, In:M:Zn = 3:1:2, etc.

[0118] When the oxide semiconductor films 107a and 107c are In-M-Zn oxides (where M represents Mg, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf), for the targets used to form the oxide semiconductor films 107a and 107c, if the atomic ratio of the metal elements is In:M:Zn = x2:y2:z2, then x2 / y2 、 x2 / y2 < x1 / y1, and z2 / y2 is 1 / 3 or more and 6 or less, further preferably 1 or more and 6 or less. By setting z2 / y2 to 1 or more and 6 or less, it becomes easier to form a CAAC-OS film as the oxide semiconductor films 107 a and 氧化物半导体膜107c. Representative examples of the atomic ratio of the metal elements in the target include In:M:Zn = 1:3:2, In:M:Z n = 1:3:4, In:M:Zn = 1:3:6, In:M:Zn = 1:3:8, In:M :Zn = 1:4:3, In:M:Zn = 1:4:4, In:M:Zn = 1:4:5, In :M:Zn = 1:4:6, In:M:Zn = 1:6:3, In:M:Zn = 1:6:4, :M:Zn = 1:6:5, In:M:Zn = 1:6:6, In:M:Zn = 1:6: 7, In:M:Zn = 1:6:8, In:M:Zn = 1:6:9, etc. 7, In:M:Zn = 1:6:8, In:M:Zn = 1:6:9, etc.

[0119] Also, when the oxide semiconductor films 107a and 107c are In-Ga oxides , for example, they can be formed by sputtering using an In-Ga metal oxide target (In:Ga = 7:93). Also, the oxide semiconductor films 107a and oxide semiconductor films 107c The In-Ga oxide film 107c is formed by a sputtering method using DC discharge. The target is In:Ga=x:y [atomic ratio], and y / (x+y) is 0.96. It is preferably set to 0.95 or less, for example 0.93.

[0120] Note that the oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107 The atomic ratios of c each include a variation of ±40% of the above atomic ratios as an error. nothing.

[0121] The atomic ratio is not limited to these, and an appropriate atomic ratio may be selected depending on the required semiconductor characteristics. Just use something.

[0122] The oxide semiconductor film 107a and the oxide semiconductor film 107c may have the same composition. For example, the oxide semiconductor film 107a and the oxide semiconductor film 107c may be formed of In:Ga:Zn=1: Atomic ratios of 3:2, 1:3:4, 1:4:5, 1:4:6, 1:4:7, or 1:4:8 In-Ga-Zn oxide may also be used.

[0123] Alternatively, the oxide semiconductor film 107a and the oxide semiconductor film 107c may have different compositions. For example, the oxide semiconductor film 107a may be made of In, Ga, and Zn having an atomic ratio of In:Ga:Zn=1:3:2. The oxide semiconductor film 107c is made of n-Ga-Zn oxide and has a thickness of In:Ga:Zn=1:3. Alternatively, an In-Ga-Zn oxide having an atomic ratio of 1:4 or 1:4:5 may be used.

[0124] The oxide semiconductor film 107a and the oxide semiconductor film 107c have a thickness of 3 nm to 100 nm. The thickness of the oxide semiconductor film 107b is 3 nm or less, or 3 nm or more and 50 nm or less. or more than 200nm or less, or 3nm or more than 100nm or less, or 3nm or more than 50nm or less Note that the oxide semiconductor films 107a and 107c are each made of an oxide semiconductor. By making the thickness thinner than the conductive film 107b, the amount of fluctuation in the threshold voltage of the transistor is reduced. It is possible to do this.

[0125] The oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107c Each interface is observed by a scanning transmission electron microscope (STEM). It may be possible to observe the lesion using a microscope.

[0126] The oxide semiconductor films 107a, 107b, and 107c are The above-described crystal structure of the oxide semiconductor film 106 can be used as appropriate.

[0127] The oxide semiconductor films 107a and 107b are less likely to have oxygen vacancies than the oxide semiconductor films 107a and 107b. The oxide semiconductor film 107c is provided in contact with the upper and lower surfaces of the oxide semiconductor film 107b. By this, oxygen vacancies in the oxide semiconductor film 107b can be reduced. The oxide semiconductor film 107b contains one or more metal elements constituting the oxide semiconductor film 107b. The oxide semiconductor film 107a and the oxide semiconductor film 107c are in contact with each other. the interface between the oxide semiconductor film 107a and the oxide semiconductor film 107b; The interface state density at the interface with the oxide semiconductor film 107b is extremely low. It is possible to reduce the oxygen vacancies contained therein.

[0128] In addition, the oxide semiconductor film 107b may be an insulating film having a different constituent element (for example, a silicon oxide film When the semiconductor comes into contact with an insulating film containing the silicon dioxide, an interface state is formed, and the interface state forms a channel. In such cases, transistors with different threshold voltages appear, and However, the apparent threshold voltage of the oxide semiconductor film 107 may vary. The oxide semiconductor film 107a containing one or more metal elements constituting the oxide semiconductor film 107b Since the oxide semiconductor film 107a is in contact with the oxide semiconductor film 107b, an interface state is formed at the interface between the oxide semiconductor film 107a and the oxide semiconductor film 107b. Therefore, by providing the oxide semiconductor film 107a, the transistor This can reduce variations in electrical characteristics such as threshold voltage.

[0129] When a channel is formed at the interface between the insulating film 108 and the oxide semiconductor film 107b, Interface scattering occurs at the interface, reducing the field-effect mobility of the transistor. The oxide semiconductor film 107c containing one or more metal elements included in the oxide semiconductor film 107b is an oxide semiconductor film. Since the oxide semiconductor film 107b is provided in contact with the oxide semiconductor film 107b, the oxide semiconductor film 107b and the oxide semiconductor At the interface with the film 107c, scattering of carriers is unlikely to occur, and the field effect mobility of the transistor is can be increased.

[0130] The oxide semiconductor films 107a and 107c are formed between the insulating film 104 and the insulating film 106. The constituent elements of the film 108 or the constituent elements of the conductive films 110 and 112 are oxide semiconductor films. 107b and acts as a barrier film to prevent impurities from being mixed into the It also works.

[0131] For example, the insulating film 104 and the insulating film 108 may be an insulating film containing silicon or a insulating film containing carbon. In the case of an insulating film containing silicon, the silicon in the insulating film 104 and the insulating film 108 or the silicon in the insulating film 104 and the insulating film 108 Carbon mixed in the insulating film 108 is mixed with the oxide semiconductor film 107a and the oxide semiconductor film 107c. Impurities such as silicon and carbon may be mixed into the oxide film from the interface to a depth of a few nanometers. When the impurity enters the semiconductor film 107b, it forms an impurity level, which acts as a donor and generates electrons. This can sometimes result in n-type conversion.

[0132] However, the thickness of the oxide semiconductor film 107a and the oxide semiconductor film 107c is several nm. If the thickness is larger than 100 μm, impurities such as silicon and carbon may reach the oxide semiconductor film 107 b. Therefore, the influence of the impurity level is reduced.

[0133] From the above, the transistor described in this embodiment has electrical characteristics such as threshold voltage. This is a transistor with reduced variation.

[0134] FIG. 5 shows a transistor with a different structure from that shown in FIG.

[0135] 5A to 5C are top views and cross-sectional views of a transistor 153 included in a semiconductor device. 5A is a top view of the transistor 153, and FIG. 5B is a top view of the transistor 153. 5(A) and FIG. 5(C) is a cross-sectional view taken along the dashed line X1-Y2 in FIG. Cross-sectional view of section X2.

[0136] As in the transistor 153 illustrated in FIG. 5, the oxide semiconductor film 106 is in contact with the insulating film 104. the oxide semiconductor film 107b in contact with the oxide semiconductor film 107b and the insulating film 108; The other configuration may be a stacked structure of the transistor 150 and the semiconductor film 107c. It is similar and has the same effect.

[0137] <Band structure> Here, the band structures of the transistors shown in FIGS. 4 and 5 will be described. 1(A) is the band structure of the transistor 153 shown in FIG. , insulating film 104, oxide semiconductor film 107a, oxide semiconductor film 107b, oxide semiconductor film 1 11(B) and the energy (Ec) of the bottom of the conduction band of the insulating film 108. ) is the band structure of the transistor 154 shown in FIG. The oxide semiconductor film 104, the oxide semiconductor film 107b, the oxide semiconductor film 107c, and the insulating film 108 The energy (Ec) at the band edge is shown.

[0138] As shown in FIG. 11A, the oxide semiconductor film 107a, the oxide semiconductor film 107b, and In the oxide semiconductor film 107c, the energy of the conduction band minimum changes continuously. , an oxide semiconductor film 107a, an oxide semiconductor film 107b, and an oxide semiconductor film 107c. This can also be understood from the fact that oxygen easily diffuses between the two because the elements that make up the two are the same. Therefore, the oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107 Although c is a laminate of films with different compositions, it can also be said to be physically continuous.

[0139] The oxide semiconductor film, which is stacked with a common main component, is not simply stacked, but is continuously Junction (here, specifically, a U-shaped well where the energy of the bottom of the conduction band changes continuously between layers) The structure is fabricated so that a U-Shape Well structure is formed. In the oxide semiconductor, defect levels such as trap centers and recombination centers, or carrier The laminated structure is formed so that there are no impurities that hinder the flow of oxygen. When impurities are mixed between layers of a semiconductor film, the continuity of the energy band is lost, and the boundary At this surface, carriers disappear due to trapping or recombination.

[0140] Note that in FIG. 11A, the Ec values ​​of the oxide semiconductor films 107a and 107c are Although the cases where they are similar are shown, they may be different.

[0141] 11A, the oxide semiconductor film 107b serves as a well, and the oxide semiconductor film 107b is In 52, it can be seen that a channel is formed in the oxide semiconductor film 107b. The oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107c have a conduction band Since the energy at the bottom changes continuously, a U-shaped well structure channel is used as a buried channel. It can also be called Nell.

[0142] 11B, the oxide semiconductor film 107b and the oxide semiconductor film 107 In c, the energy of the conduction band minimum may change continuously.

[0143] As shown in FIG. 11B, the oxide semiconductor film 107b serves as a well, and the oxide semiconductor film 107b is In 53, it can be seen that a channel is formed in the oxide semiconductor film 107b.

[0144] The transistor 152 illustrated in FIG. 4 includes an oxide semiconductor film 107b containing one kind of metal element. Since the oxide semiconductor film 107a and the oxide semiconductor film 107c contain the above-mentioned , the interface between the oxide semiconductor film 107a and the oxide semiconductor film 107b, and the oxide semiconductor film 1 Therefore, an interface state is less likely to be formed at the interface between the oxide semiconductor film 107c and the oxide semiconductor film 107b. By providing the compound semiconductor film 107a and the oxide semiconductor film 107c, It is possible to reduce variations and fluctuations in electrical characteristics such as threshold voltage.

[0145] The transistor 153 illustrated in FIG. 5 includes an oxide semiconductor film 107b containing one kind of metal element. Since the oxide semiconductor film 107c contains the above-mentioned oxide semiconductor film, the oxide semiconductor film 107c and the oxide semiconductor film Therefore, the interface state is less likely to be formed at the interface with the oxide semiconductor film 107b. By providing 107c, variations in electrical characteristics such as the threshold voltage of the transistor and Fluctuations can be reduced.

[0146] <Configuration 4 of semiconductor device> Next, another configuration of the semiconductor device will be described with reference to FIG.

[0147] 6A to 6D are top views and cross-sectional views of a transistor 154 included in a semiconductor device. 6A is a top view of the transistor 154, and FIGS. 6B and 6D are side views. 6(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 6(A), and FIG. 6(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 6(A). FIG. 1 is a cross-sectional view taken along the dashed dotted line X1-X2.

[0148] The transistor 154 illustrated in FIG. 6 overlaps with the oxide semiconductor film 106 with the insulating film 104 interposed therebetween. That is, the conductive film 120 serves as a gate electrode. The transistor 154 has a dual gate structure. The other configurations are similar to those of the transistor 150, and similar effects are achieved.

[0149] The conductive film 114 and the conductive film 120 are not connected, and different potentials are applied to them. The threshold voltage of the transistor 154 can be controlled. An example of a cross section in this case is shown in FIG. When the conductive film 114 and the conductive film 120 are not connected to each other, either A signal to turn the transistor on and off is supplied to one side, and a constant potential is supplied to the other side. Alternatively, as shown in FIG. 6B, the conductive film 114 and the conductive film 120 may be connected to each other. By applying the same potential, the initial characteristic variations are reduced, and -Temperature) stress test degradation suppression and at different drain voltages In addition, the oxide semiconductor film 106 can suppress fluctuations in the on-state voltage. In this case, the area through which carriers flow is larger in the film thickness direction, so the amount of carrier movement is As a result, the on-current of the transistor 154 increases and the field effect transfer The transistor channel length is set to less than 2.5 μm or 1.45 μm or more. By reducing the thickness to 0.2 μm or less, the on-current is further increased and the field effect mobility is improved. It is possible.

[0150] The conductive film 120, the conductive film 110, and the conductive film 112 are arranged so as not to overlap each other. An example of this case is shown in FIG. When the conductive film 120 is connected, noise can be prevented from entering.

[0151] Alternatively, the conductive film 120, the conductive film 110, and the conductive film 112 may be arranged so as to overlap with each other. An example of this case is shown in FIG. 39B. When the conductive film 120 is not connected and a constant potential is applied to the conductive film 120, the oxide semiconductor An electrical potential can be applied across the membrane 106 .

[0152] <Method 1 for manufacturing semiconductor device> Next, a manufacturing method of the transistor 150 shown in FIG. 1 will be described with reference to FIGS. do.

[0153] The films (insulating film, oxide semiconductor film, conductive film, etc.) constituting the transistor 150 are formed by sputtering. ring method, chemical vapor deposition (CVD) method, vacuum evaporation method, pulsed laser deposition (PLD) method Alternatively, the film can be formed by a coating method or a printing method. Typical methods include sputtering and plasma enhanced chemical vapor deposition (PECVD). However, a thermal CVD method may also be used. An example of a thermal CVD method is MOCVD (metal organic chemical vapor deposition). Alternatively, atomic layer deposition (ALD) may be used.

[0154] In the thermal CVD method, the pressure in the chamber is atmospheric or reduced, and the source gas and oxidant are simultaneously mixed. The reaction is carried out in the chamber near or on the substrate, where it is deposited on the substrate to form a film. As described above, the thermal CVD method is a film formation method that does not generate plasma. This has the advantage that defects are not generated due to damage.

[0155] In addition, in the ALD method, the pressure inside the chamber is atmospheric or reduced, and the source gas for the reaction is The gases are introduced into the chamber in sequence, and the film is formed by repeating this gas introduction sequence. By switching each switching valve (also called high-speed valve), two or more types of raw materials can be The source gases are supplied to the chamber in order, and the first source gas is supplied to the chamber in order to prevent the mixture of the source gases. Simultaneously with or after the second gas, an inert gas (argon, nitrogen, etc.) is introduced. Introduce the source gas. If an inert gas is introduced at the same time, the inert gas is used as a carrier gas. In addition, an inert gas may be introduced at the same time as the second source gas is introduced. Alternatively, instead of introducing an inert gas, the first source gas is discharged by vacuum evacuation, and then the second source gas is introduced. The first source gas may be adsorbed on the surface of the substrate to form a first monoatomic layer. The second monoatomic layer is formed by reacting with the second source gas introduced later. Layer upon layer is laminated to form a thin film.

[0156] This gas introduction sequence is repeated multiple times while controlling it until the desired thickness is achieved. The thickness of the thin film increases depending on the number of times the gas introduction sequence is repeated. Therefore, precise film thickness control is possible, and fine transistors can be fabricated. It is suitable for manufacturing.

[0157] As shown in FIG. 7(C), an insulating film 104 is formed on the substrate 102.

[0158] The insulating film 104 can be formed by a method such as sputtering, CVD, evaporation, or pulsed laser deposition (PLD). The insulating film 102 can be formed by using a suitable method such as a lithography method, a printing method, or a coating method. After forming the film, oxygen can be added to the insulating film to form the insulating film 104. The oxygen added to the insulating film can be oxygen radicals, oxygen atoms, oxygen atomic ions, or oxygen molecular ions. The doping method includes ion doping, ion implantation, plasma treatment, etc. Furthermore, after forming a film that suppresses oxygen desorption on the insulating film, the insulating film is Oxygen may be added to the membrane.

[0159] In addition, the substrate placed in the evacuated processing chamber of the plasma CVD device is heated to 180°C or higher. The temperature is kept at 280°C or below, or 200°C to 240°C, and the raw material gas is introduced into the processing chamber. The pressure in the treatment room should be between 100 Pa and 250 Pa, or between 100 Pa and 200 Pa. The electrode in the processing chamber is set to 0.17 W / cm 2 More than 0.5W / cm 2 Below, again is 0.25W / cm 2 More than 0.35W / cm 2 Under the following conditions for supplying high frequency power: A silicon oxide film or a silicon oxynitride film capable of releasing oxygen by heat treatment is used as an insulating film. It can be formed as a veneer 104.

[0160] Here, a film for suppressing oxygen desorption is formed on the insulating film, and then oxygen is introduced into the insulating film through the film. The method of adding the element will be explained with reference to FIGS. 7(A) and 7(B).

[0161] As shown in FIG. 7(A), an insulating film 103 is formed on a substrate 102 .

[0162] Next, as shown in FIG. 7(B), a film 119 for suppressing oxygen desorption is formed on the insulating film 103. Next, oxygen 121 is added to the insulating film 103 through the film 119.

[0163] The film 119 for suppressing oxygen desorption may be made of aluminum, chromium, tantalum, titanium, molybdenum, or the like. a metal element selected from iridium, nickel, iron, cobalt, and tungsten; Alloys containing the above elements, alloys combining the above metal elements, alloys containing the above metal elements metal nitrides containing the above-mentioned metal elements, metal oxides containing the above-mentioned metal elements, metal nitrides containing the above-mentioned metal elements, The insulating film is formed using a conductive material such as an oxide.

[0164] The thickness of the film 119 that suppresses oxygen desorption is 1 nm or more and 20 nm or less, or 2 nm or more. It can be made 10 nm or less.

[0165] The oxygen 121 can be added to the insulating film 103 through the film 119 by ion doping. The film 119 is provided on the insulating film 103, and oxygen is introduced into the film 119. By adding the above, the film 119 functions as a protective film that suppresses oxygen desorption from the insulating film 103. Therefore, more oxygen can be added to the insulating film 103.

[0166] In addition, when oxygen is introduced in plasma treatment, the oxygen is excited by microwaves to form high-density oxygen. By generating oxygen plasma, the amount of oxygen introduced into the insulating film 103 can be increased. .

[0167] After that, the film 119 is removed, and oxygen is left on the substrate 102 as shown in FIG. 7(C). The insulating film 104 to which oxygen is added can be formed. In the case where the insulating film 104 can be formed, the treatment of adding oxygen shown in FIG. It is not necessary to do so.

[0168] Next, as shown in FIG. 7D, an oxide semiconductor film 106 is formed over the insulating film 104. Next, the insulating film 108 is formed over the insulating film 104 and the oxide semiconductor film 106 .

[0169] A method for forming the oxide semiconductor film 106 is described below. Ring method, coating method, pulsed laser deposition method, laser ablation method, thermal CVD method, etc. Next, a mask is formed on the oxide semiconductor film by a lithography process. After forming the mask, part of the oxide semiconductor film is etched using the mask. As shown in FIG. 1D, the oxide semiconductor film 106 can be formed. Note that the oxide semiconductor film 106 is formed by etching part of the oxide semiconductor film. After that, a heat treatment may be carried out.

[0170] In addition, by using a printing method for the oxide semiconductor film 106, it is possible to form an oxide semiconductor film having element isolation. The membrane 106 can be formed directly.

[0171] When an oxide semiconductor film is formed by a sputtering method, a power source for generating plasma is used. The device may be an RF power supply device, an AC power supply device, a DC power supply device, or the like. The CAAC-OS film can be formed by using an AC power supply or a DC power supply. It is also possible to form an oxide semiconductor film by sputtering using an RF power supply. Rather than using a sputtering method using an AC power supply or a DC power supply, an oxide semiconductor film is formed by sputtering. It is preferable to form the film on a thin film substrate because the film thickness distribution, film composition distribution, or crystallinity distribution will be uniform. stomach.

[0172] The sputtering gas is a rare gas (typically argon), oxygen, or a mixture of rare gas and oxygen. In the case of a mixture of rare gas and oxygen, the ratio of the oxygen gas to the rare gas is A higher ratio is preferred.

[0173] The target may be appropriately selected depending on the composition of the oxide semiconductor film to be formed. .

[0174] Note that when the oxide semiconductor film is formed by, for example, a sputtering method, The 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. The oxide semiconductor film is formed at a temperature of 350° C. or lower to form a CAAC-OS film. Furthermore, by setting the substrate temperature to 25°C or higher and lower than 150°C, it is possible to form a microcrystalline oxide semiconductor. A conductive film can be formed.

[0175] In addition, in order to form a CAAC-OS film described later, the following conditions are preferably applied: It's nice.

[0176] By suppressing the inclusion of impurities during film formation, it is possible to prevent the crystal state from being destroyed by impurities. For example, the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be In addition, the impurity concentration in the deposition gas can be reduced. A deposition gas having a temperature of -80°C or lower or -100°C or lower is used.

[0177] In addition, by increasing the oxygen ratio in the deposition gas and optimizing the power, plasma damage during deposition can be reduced. The oxygen ratio in the deposition gas is preferably 30% by volume or more, or 100% by volume or more. Let it be %.

[0178] After the oxide semiconductor film is formed, heat treatment is performed to dehydrogenate or The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate distortion point. Alternatively, the temperature is 250°C or higher and 450°C or lower, or 300°C or higher and 450°C or lower.

[0179] Heat treatment is carried out using rare gases such as helium, neon, argon, xenon, krypton, or It is carried out in an inert gas atmosphere containing nitrogen, or after heating in an inert gas atmosphere, it is heated in an oxygen atmosphere. It should be noted that the inert atmosphere and oxygen atmosphere do not contain hydrogen, water, etc. The treatment time is preferably from 3 minutes to 24 hours.

[0180] The heat treatment can be carried out using an electric furnace, an RTA device, or the like. Therefore, heat treatment can be performed at a temperature above the strain point of the substrate for a short period of time. The processing time can be reduced.

[0181] The oxide semiconductor film is formed while being heated, and after the oxide semiconductor film is formed, By performing heat treatment, the oxide semiconductor film is The hydrogen concentration is 5×10 19 atoms / cm 3 or less, or 1×10 19 atoms / c m 3 Below, 5 x 10 18 atoms / cm 3 or less, or 1×10 18 atoms / cm 3 or less, or 5 x 10 17 atoms / cm 3 or less, or 1×10 16 atoms / cm 3 It can be as follows:

[0182] Oxide semiconductor films, such as InGaZnO, are formed using a deposition system that uses ALD. X (X>0) When forming a film, In(CH3)3 gas and O3 gas are introduced in sequence and repeatedly to form InO Then, Ga(CH3)3 gas and O3 gas are introduced simultaneously to form a GaO layer. Then, Zn(CH3)2 and O3 gases are introduced simultaneously to form a ZnO layer. The order of these layers is not limited to this example. Also, by mixing these gases, the InGaO2 layer and mixed compound layers such as InZnO2 layer, GaInO layer, ZnInO layer, and GaZnO layer. It is also possible to use H2O gas bubbled with an inert gas such as Ar instead of O3 gas. However, it is preferable to use O3 gas that does not contain H. In(CH3) In place of the gas In(C2H5)3, gas Ga(CH3)3 may be used. Alternatively, Ga(C2H5)3 gas may be used. That's fine.

[0183] Here, an oxide semiconductor film having a thickness of 35 nm is formed by a sputtering method. Heat treatment is performed to move oxygen contained in the insulating film 104 to the oxide semiconductor film. A mask is formed over the oxide semiconductor film, and part of the oxide semiconductor film is selectively etched. In this way, the oxide semiconductor film 106 is formed.

[0184] The heat treatment should be performed at a temperature between 350°C and 650°C, or between 450°C and 600°C. By doing this, the CAAC conversion rate described below can be between 60% and 100%, or between 80% and 100%. Oxides that are less than 0.00%, or 90% to less than 100%, or 95% to 98% In addition, an oxide semiconductor film with reduced contents of hydrogen, water, and the like can be obtained. That is, an oxide semiconductor having a low impurity concentration and a low density of defect states can be obtained. A film can be formed.

[0185] The insulating film 108 can be formed by the same method as that for forming the insulating film 104, as appropriate.

[0186] A silicon oxide film or a silicon oxynitride film is formed as the insulating film 108 by using a CVD method. In this case, the source gas may be a deposition gas containing silicon and an oxidizing gas. It is preferable to use a gas containing silicon. Typical examples of deposition gases containing silicon include silane, di Examples of oxidizing gases include silane, trisilane, and fluorinated silane. Examples of oxidizing gases include oxygen, ozone, monoacid Examples include dinitrogen fluoride and nitrogen dioxide.

[0187] In addition, the insulating film 108 is formed by mixing an oxidizing gas with a deposition gas that is 20 times or more and 100 times or more. The pressure in the processing chamber should be less than 100 Pa, or 50 Pa or less. By using a CVD method with a thickness of 0.1 or less, a silicon oxynitride film with a small amount of defects can be formed. This can be done.

[0188] The insulating film 108 is placed in a vacuum-evacuated processing chamber of a plasma CVD apparatus. The substrate is maintained at a temperature of 280°C or higher and 400°C or lower, and raw material gas is introduced into the processing chamber. The pressure in the air is set to 20 Pa or more and 250 Pa or less, more preferably 100 Pa or more and 250 Pa or less. Under the conditions under which high frequency power is supplied to an electrode provided in the processing chamber, the insulating film 108 and As a result, a dense silicon oxide film or silicon oxynitride film can be formed.

[0189] The insulating film 108 may be formed by a plasma CVD method using microwaves. Microwaves refer to the frequency range from 300MHz to 300GHz. In this case, the electron temperature is low and the electron energy is small. A smaller proportion of the electrons are used to accelerate the molecules, and more are used to dissociate and ionize the molecules. It is possible to excite a high density plasma (high density plasma). The insulating film 108 is formed with less defects due to less plasma damage to the surface to be deposited and the deposits. It is possible.

[0190] The insulating film 108 can be formed by a CVD method using organic silane gas. The organic silane gases include ethyl silicate (TEOS: chemical formula Si(OC2H5)4), Tetramethylsilane (TMS: chemical formula Si(CH3)4), tetramethylcyclotetrasilane Octamethylcyclotetrasiloxane (TMCTS), Octamethylcyclotetrasiloxane (OMCTS), Hexa Methyldisilazane (HMDS), triethoxysilane (SiH(OC2H5)3), tri Silicon-containing compounds such as dimethylaminosilane (SiH(N(CH3)2)3) are used. By using the CVD method with organic silane gas, it is possible to obtain insulating films with high coating properties. A membrane 108 can be formed.

[0191] When a gallium oxide film is formed as the insulating film 108, MOCVD (Metal Organic Chemical Vapor Deposition (OCVD) method It can be achieved.

[0192] The insulating film 108 is formed by a thermal CVD method such as MOCVD or an ALD method. In the case of forming a hafnium oxide film, a liquid containing a solvent and a hafnium precursor compound (hafnium oxide) is used. Hafnium alkoxide solution, typically tetrakisdimethylamidohafnium (TDMA) Two types of gases are used: a raw material gas made by vaporizing hydrogen (H)) and ozone (O3) as an oxidizing agent. The chemical formula for tetrakisdimethylamidohafnium is Hf[N(CH3)2]4 Other liquid materials include tetrakis(ethylmethylamido)hafnium. .

[0193] The insulating film 108 is formed by a thermal CVD method such as MOCVD or an ALD method. In the case of forming an aluminum oxide film, a liquid containing a solvent and an aluminum precursor compound is used. The raw material gas (e.g., trimethylaluminum TMA) is vaporized, and H2O is used as an oxidizer. Two types of gases are used. The chemical formula of trimethylaluminum is Al(CH3)3. Other liquid materials include tris(dimethylamido)aluminum and triisobutyl aluminum tris(2,2,6,6-tetramethyl-3,5-hepta) In addition, by forming it using the ALD method, the coverage is high and the film thickness is thin. Therefore, it is possible to form a thin insulating film 108.

[0194] The insulating film 108 is formed by a thermal CVD method such as MOCVD or an ALD method. When forming a silicon film, hexachlorodisilane is adsorbed onto the surface to be formed, and the adsorbed material Removes chlorine and provides radicals of oxidizing gases (O2, nitrous oxide) to absorb and react with it.

[0195] Here, a silicon oxynitride film is formed as the insulating film 108 by plasma CVD. do.

[0196] Next, as shown in FIG. 8(A), a mask is formed on the insulating film 108 by a lithography process. After the formation of the insulating film 108, part of the insulating film 108 is etched to expose part of the oxide semiconductor film 106. An opening 140a and an opening 140b are formed.

[0197] The insulating film 108 is etched by wet etching or / and dry etching. The chiming method can be used as appropriate.

[0198] Next, as shown in FIG. 8B, a conductive film 106 is formed over the oxide semiconductor film 106 and the insulating film 108. Form 09.

[0199] When a low-resistance material is used for the conductive film 109, for example, the low-resistance material is mixed into the oxide semiconductor film. If the conductive film 1 is introduced, the electrical characteristics of the transistor may be deteriorated. By forming the insulating film 108 before forming the oxide semiconductor film 109, the channel of the oxide semiconductor film 106 Since the conductive film 109 is not in contact with the conductive film 109, the electrical characteristics of the transistor, typically the threshold voltage, are not changed. You can reduce the amount.

[0200] The conductive film 109 can be formed by a sputtering method, a vacuum deposition method, a pulsed laser deposition (PLD) method, It can be formed by using a thermal CVD method or the like.

[0201] In addition, a tungsten film is formed as the conductive film 109 using a film forming apparatus that uses ALD. In this case, WF6 gas and B2H6 gas are introduced repeatedly in sequence to form the initial Then, WF6 gas and H2 gas are introduced simultaneously to form a tungsten film. It should be noted that SiH4 gas may be used instead of B2H6 gas.

[0202] Next, as shown in FIG. 8(C), a mask 1 is formed on the conductive film 109 by a lithography process. After forming the conductive film 109, the conductive film 109 is immersed in an etching solution and / or etching gas 123. By exposing the conductive film 110, the conductive film 112, and the conductive film 114 are formed. 0, the conductive film 112 and the conductive film 114 are formed by processing the conductive film 109. , the same metal, in other words, the same metal element.

[0203] The conductive film 109 is etched by wet etching or / and dry etching. After the conductive film 109 is etched, the insulating film 1 A cleaning step may be performed to remove residues on the sides of the gate electrode and Therefore, leakage current between the conductive film 114 and the oxide semiconductor film 106 can be reduced. It is Noh.

[0204] Note that the conductive films 110, 112, and 114 can be formed by the following method instead of the above method. It may also be formed by electrolytic plating, printing, ink jetting, or the like.

[0205] Next, as shown in FIG. 8D, the oxide semiconductor film 106 is treated with the mask 111 left. The impurity element 117 is added. As a result, the oxide semiconductor film covered with the mask 111 The impurity element 117 is added to the region where the oxide is not present. Oxygen vacancies are formed in the semiconductor film.

[0206] The impurity element 117 can be added by ion doping, ion implantation, plasma In the case of plasma treatment, the plasma is heated in a gas atmosphere containing the impurity element to be added. By generating a plasma and performing a plasma treatment, impurity elements can be added. The plasma generating device may be a dry etching device or a plasma CVD device. A high-density plasma CVD apparatus or the like can be used.

[0207] The source gases for the impurity element 117 are B2H6, PH3, CH4, N2, and NH3 , AlH3, AlCl3, SiH4, Si2H6, F2, HF, H2 and one or more of the rare gases Alternatively, B2H6, PH3, N2, NH3 diluted with rare gases can be used. One or more of AlH3, AlCl3, F2, HF, and H2 can be used. Diluted B2H6, PH3, N2, NH3, AlH3, AlCl3, F2, HF, and The impurity element 117 is added to the oxide semiconductor film 106 using one or more of H2, and hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, and chlorine. One or more of these can be added to the oxide semiconductor film 106 at the same time.

[0208] Alternatively, after adding a rare gas to the oxide semiconductor film 106, B2H6, PH3, CH4, or N 2, NH3, AlH3, AlCl3, SiH4, Si2H6, F2, HF, and H2 The above may be added to the oxide semiconductor film 106.

[0209] or B2H6, PH3, CH4, N2, NH3, AlH3, AlCl3, SiH4 After adding one or more of Si2H6, F2, HF, and H2 to the oxide semiconductor film 106, The gas may be added to the oxide semiconductor film 106 .

[0210] The addition of the impurity element 117 is controlled by appropriately setting implantation conditions such as acceleration voltage and dose amount. For example, when adding argon by ion implantation, the acceleration voltage is 10 kV, The amount of deviation is 1×10 13 ions / cm 2 More than 1×10 16 ions / cm 2 If we do the following, For example, 1×10 14 ions / cm 2 In addition, phosphorus can be implanted by ion implantation. When adding ions, the acceleration voltage is 30 kV and the dose is 1 × 10 13 ions / cm2 Below top 5×10 16 ions / cm 2 For example, 1×10 15 ions / c m 2 This can be done as follows.

[0211] Here, when the impurity element 117 is added to the oxide semiconductor film 106, The conceptual diagrams of the region doped with impurity elements are shown in Figures 10(A), 10(B), and 10(C). 1B and 1C are enlarged views of the oxide semiconductor film 106 and its vicinity.

[0212] As shown in FIG. 10(A), the region where the impurity element 117 is added is covered with the insulating film 104, the oxide semiconductor, and the like. The oxide semiconductor film 106 may be formed on the conductive film 106 and the insulating film 108. In the depth direction of the region where the doped region is exposed, the end 135 of the doped region is located in the insulating film 104. Note that the depth direction is parallel to the thickness direction of the oxide semiconductor film 106 and the insulating film 108. The direction is from 108 to the insulating film 104.

[0213] Alternatively, as shown in FIG. 10B, the region to which the impurity element 117 is added is formed in the oxide semiconductor film. In some cases, the insulating film 106 and the insulating film 108 are formed with a thin film. In the depth direction of the doped region, the end 136 of the doped region is located between the insulating film 104 and the oxide semiconductor film Located at the interface of 106.

[0214] Alternatively, as shown in FIG. 10C, the region to which the impurity element 117 is added is formed in the oxide semiconductor film. In some cases, the insulating film 106 and the insulating film 108 are formed with a thin film. In the depth direction of the doped region, an end portion 137 of the doped region is located in the oxide semiconductor film 106. do.

[0215] As a result, a low-resistance region can be formed in the oxide semiconductor film 106. Specifically, The region 106b and the region 106c shown in FIG. is added to the oxide semiconductor film 106 through the insulating film 108, and thus is After that, as shown in FIG. 9(A), the mask 111 is removed. except.

[0216] Note that here, the impurity element 117 is added to the oxide semiconductor film 106 using the mask 111. After removing the mask 111, the conductive film 110, the conductive film 112, and the conductive film 11 The impurity element 117 may be added to the oxide semiconductor film 106 using the mask 4.

[0217] After that, a heat treatment is performed to further increase the conductivity of the region where the impurity element 117 is added. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate strain point, or 250° C. ℃ or higher and 450℃ or lower, or 300℃ or higher and 450℃ or lower.

[0218] Next, as shown in FIG. 9B, the oxide semiconductor film 106, the insulating film 108, and the conductive film 110 An insulating film 116 is formed over the conductive film 112 and the conductive film 114, and an insulating film 116 is formed over the insulating film 116. Form 118.

[0219] The insulating films 116 and 118 are formed by appropriately using the method for forming the insulating films 104 and 108. You can be there.

[0220] In addition, the substrate placed in the evacuated processing chamber of the plasma CVD device is heated to 180°C or higher. The temperature is kept at 280°C or below, or between 200°C and 240°C, and the raw material gas is introduced into the processing chamber. The pressure in the processing chamber should be between 100 Pa and 250 Pa, or between 100 Pa and 200 Pa. a or less, and the electrode installed in the processing chamber is 0.17 W / cm 2 More than 0.5W / cm 2 below , or 0.25 W / cm 2 More than 0.35W / cm 2 The following high frequency power supply conditions are met: Therefore, a silicon oxide film or a silicon oxynitride film capable of releasing oxygen by heat treatment is used. The insulating film 116 can be formed of a silicon film.

[0221] Alternatively, the oxide semiconductor film 106, the conductive film 110, the conductive film 112, and the conductive film 114 may be formed on the oxide semiconductor film 106, the conductive film 110, the conductive film 112, and the conductive film 114. After forming the aluminum film or aluminum oxide film, heat treatment is performed to form the film shown in FIG. In the region 106b, oxygen contained in the oxide semiconductor film 106 is oxidized to the aluminum film or reacts with the aluminum oxide film to form an aluminum oxide film as the insulating film 116. In both cases, oxygen vacancies are formed in the region 106b in FIG. It is possible to increase the conductivity of 06b.

[0222] After that, a heat treatment is performed to further increase the conductivity of the region where the impurity element 117 is added. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate strain point, or 250° C. ℃ or higher and 450℃ or lower, or 300℃ or higher and 450℃ or lower.

[0223] Through the above steps, a transistor can be manufactured.

[0224] <Method 2 for manufacturing semiconductor device> A method for manufacturing the transistor 151 shown in FIG. 3 will be described. The conductive film 110, the conductive film 112, and the conductive film 110c included in the conductive film 114 of 151, the formation of the conductive film 112c and the conductive film 114c, and the addition of the impurity element 1 to the oxide semiconductor film 106. The step of adding 17 will be described.

[0225] 7 and 8(A) to 8(C), an insulating film 104 and an oxide film 105 are formed on the substrate 102. The compound semiconductor film 106, the insulating film 108, the conductive film 110, the conductive film 112, the conductive film 114, and the Form Sq 111.

[0226] Next, as shown in FIG. 8D, an impurity element 117 is added to the oxide semiconductor film 106. .

[0227] Next, the mask 111 is removed.

[0228] Next, the conductive film 110 included in each of the conductive film 110, the conductive film 112, and the conductive film 114 b) The conductive film 112b and the conductive film 114b are exposed to plasma generated in a reducing atmosphere, and the conductive film 112b and the conductive film 114b are The oxides on the surfaces of the film 110b, the conductive film 112b, and the conductive film 114b are reduced. The conductive film 110b, the conductive film 112b, and the conductive film 112a are heated at a temperature of 00° C. or higher and 400° C. or lower. Next, the conductive film 110b, the conductive film 112b, and the conductive film 114b are exposed to silane. By exposing the conductive material to plasma generated in an atmosphere containing nitrogen, such as ammonia or nitrogen, The conductive film 110c, the conductive film 112c, and the conductive film 114c are made of CuSi x N y (x>0, y>0).

[0229] In addition, when exposed to plasma generated in an atmosphere containing nitrogen such as ammonia or nitrogen, In this case, the oxide semiconductor film 106 is formed in an atmosphere containing nitrogen such as ammonia or nitrogen. The oxide semiconductor film 106 is exposed to plasma, and nitrogen and / or hydrogen are added to the oxide semiconductor film 106. is possible.

[0230] Note that the mask 111 is removed before the impurity element 117 is added to the oxide semiconductor film 106. The conductive film 110c and the conductive film 110c included in the conductive film 110, the conductive film 112, and the conductive film 114 are 112c and a conductive film 114c may be formed.

[0231] After that, the transistor 151 can be manufactured through the process of FIG.

[0232] The transistor described in this embodiment includes the conductive film 110, the conductive film 112, and the conductive film 114. Since there is no overlap, it is possible to reduce the parasitic capacitance and the on-current is large. The transistor described in this embodiment can stably form a low-resistance region; Compared to conventional devices, the on-state current is improved and the variation in the electrical characteristics of the transistor is reduced.

[0233] In this embodiment, when an oxide semiconductor film is used for a channel or the like, Although an example has been given, one aspect of the embodiment of the present invention is not limited to this. For example, In the vicinity thereof, in the source region, the drain region, etc., depending on the circumstances, Therefore, Si (silicon), Ge (germanium), SiGe (silicon germanium), It may be formed of a material including GaAs (gallium arsenide), etc.

[0234] As described above, the structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiments. They can be used in combination.

[0235] (Embodiment 2) In this embodiment mode, one mode of a semiconductor device and a manufacturing method of the semiconductor device will be described with reference to FIGS. 2 will be used for the description. In this embodiment, the low resistance region is formed in a simple manner as compared with the first embodiment. The manufacturing method is different.

[0236] <Configuration 5 of Semiconductor Device> FIG. 12 shows a top-gate transistor as an example of a transistor included in a semiconductor device. This indicates a transistor.

[0237] 12A to 12C are top views and diagrams of a transistor 190 included in a semiconductor device. 12A is a top view of the transistor 190, and FIG. 12B is a cross-sectional view of the transistor 190. 12(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 12(A), and FIG. 12(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. FIG. 1 is a cross-sectional view taken along the dashed dotted line X1-X2.

[0238] The transistor 190 shown in FIG. 12 is an oxide film on an insulating film 164 formed on a substrate 162. an oxide semiconductor film 166; an insulating film 168 in contact with the oxide semiconductor film 166; The conductive film 170 is in contact with the oxide semiconductor film 166 in a part of the opening 180a, and the insulating film 16 The conductive film 172 is in contact with the oxide semiconductor film 166 in part of the opening 180b of FIG. The conductive film 174 overlaps with the oxide semiconductor film 166 with the film 168 interposed therebetween. An insulating film 176 is provided on the resistor 190. An insulating film 178 is also provided on the insulating film 176. may be provided.

[0239] In the oxide semiconductor film 166, the conductive film 170, the conductive film 172, and the conductive film 174 overlap. The region where oxygen vacancies do not occur contains elements that form oxygen vacancies. , will be explained as impurity elements. Typical examples of impurity elements include hydrogen and rare gas elements. Representative examples of rare gas elements are helium, neon, argon, krypton, and xenon. Furthermore, impurity elements such as boron, carbon, nitrogen, fluorine, aluminum, and silicon can be used. The oxide semiconductor film 166 may contain elements such as silicon, phosphorus, and chlorine.

[0240] The insulating film 176 is a film containing hydrogen, and is typically a nitride insulating film. When the insulating film 176 is in contact with the oxide semiconductor film 166, hydrogen contained in the insulating film 176 is oxidized to the oxide semiconductor film 166. As a result, the oxide semiconductor film 166 that is in contact with the insulating film 176 In the region where the hydrogen is present, a large amount of hydrogen is contained.

[0241] When a rare gas element is added to an oxide semiconductor film as an impurity element, The bond between the metal element and oxygen is broken, and oxygen vacancies are formed. The interaction between oxygen vacancies and hydrogen increases the electrical conductivity of the oxide semiconductor film. When hydrogen enters the oxygen vacancies in the oxide semiconductor film, electrons are generated as carriers. This results in a high conductivity.

[0242] Here, an enlarged view of the vicinity of the oxide semiconductor film 166 is shown in FIG. The compound semiconductor film 166 has a region 166a in contact with the conductive film 170 or the conductive film 172 and an insulating region 166b in contact with the conductive film 170 or the conductive film 172. A region 166b in contact with the film 176, and regions 166c and 166d overlapping with the insulating film 168 It has the following.

[0243] The region 166a functions as a source region and a drain region. The region 166a in contact with the film 172 is electrically conductive, similar to the region 106a shown in the first embodiment. The raised portions function as source and drain regions.

[0244] The region 166b and the region 166c function as low resistance regions. The region 166c contains at least a rare gas and hydrogen as impurity elements. The region 166b has a higher impurity element concentration than the region 166c. In this case, part of the region 166c may overlap with the conductive film 174.

[0245] In the case where the oxide semiconductor film 166 is formed by a sputtering method, the regions 166a to 166c are 66d each contain a rare gas element, and compared to region 166a and region 166d, regions The regions 166b and 166c have higher concentrations of rare gas elements. When 66 is formed by sputtering, a rare gas is used as the sputtering gas. Therefore, a rare gas is contained in the oxide semiconductor film 166, and the regions 166b and 166c are In c, rare gases are intentionally added to form oxygen vacancies. In addition, the regions 166b and 166c are different from the regions 166a and 166d. A rare gas element may be added.

[0246] In addition, in the regions 166b and 166c, the amount of oxygen vacancies is greater than the amount of hydrogen. In this case, the carrier density in the regions 166b and 166c can be controlled by controlling the amount of hydrogen. Alternatively, the amount of oxygen vacancy in the region 166b and the region 166c can be controlled. When the amount of hydrogen is relatively large, the amount of oxygen vacancies can be controlled to reduce the area between the region 166b and the region 16 The carrier density of the region 166b and the region 166c can be controlled. Carrier density 5×10 18 pieces / cm 3 or more, preferably 1 × 10 19 pieces / cm 3 That's all. More preferably, 1×10 20 pieces / cm 3 By doing so, the channel, source region, and drain region It is possible to create a transistor with low resistance between the drain region and the gate, and a large on-current. is.

[0247] In addition, since the region 166b is in contact with the insulating film 176, it is In comparison, the concentration of hydrogen is higher in the region 166b. When hydrogen diffuses, the region 166c has a higher hydrogen concentration than the region 166a and the region 166d. However, the hydrogen concentration is higher in the region 166b than in the region 166c.

[0248] In the region 166b and the region 166c, hydrogen concentration obtained by secondary ion mass spectrometry is The concentration is 8 x 10 19 atoms / cm 3 or more, or 1×10 20 atoms / cm 3 or more, or 5 x 10 20 atoms / cm 3 It is possible to set the above. The hydrogen concentration obtained by secondary ion mass spectrometry in the region 6a and the region 166d is 5×10 19 atoms / cm 3 or less, or 1×10 19 atoms / cm 3 or less, or 5 x 10 18 atoms / cm 3 or less, or 1×10 18 atoms / cm3 or less, or 5x 10 17 atoms / cm 3 or less, or 1×10 16 atoms / cm 3 The following shall be This can be done.

[0249] In addition, impurity elements such as boron, carbon, nitrogen, fluorine, aluminum, silicon, and lithium are used. When chlorine or chlorine is added to the oxide semiconductor film 166, the regions 166b and 166c are Therefore, compared with the region 166a and the region 166d, the region 166c has an impurity element. The regions 166b and 166c have higher concentrations of impurity elements. In the region 166c, the concentration of impurity elements obtained by secondary ion mass spectrometry is 5×1 0 18 atoms / cm 3 More than 1×10 22 atoms / cm 3 or less, or 1×10 1 9 atoms / cm 3 More than 1×10 21 atoms / cm 3 or less, or 5 x 10 19 a toms / cm 3 5x10 or more 20 atoms / cm 3 It can be as follows:

[0250] Compared to the region 166d, the regions 166b and 166c have a high hydrogen concentration and are rare. The amount of oxygen deficiency caused by the addition of gas elements is large. This results in high conductivity and a low resistance region. Typically, the resistivity of the region 166b and the region 166c is 1×10 -3 Ωcm or more 1×10 4 Less than Ωcm, or 1×10 -3 Ωcm or more 1×10-1 Ωcm not yet It can be satisfied.

[0251] In the regions 166b and 166c, the amount of hydrogen is equal to or greater than the amount of oxygen vacancies. The smaller the oxygen vacancy, the more hydrogen is likely to be captured by the oxygen vacancy and diffuse into the region 166d, which is the channel. As a result, a transistor with normally-off characteristics can be fabricated.

[0252] Region 166d functions as a channel.

[0253] In the insulating film 168, a region overlapping with the oxide semiconductor film 166 and the conductive film 174 is a gate electrode. The insulating film 168 functions as an insulating film. The region where the conductive film 170 and the conductive film 172 overlap functions as an interlayer insulating film.

[0254] The conductive films 170 and 172 function as a source electrode and a drain electrode. The conductive film 174 functions as a gate electrode.

[0255] The transistor 190 described in this embodiment has a region 166d serving as a channel and Between the region 166a functioning as the source region and the drain region, there is provided a region functioning as a low resistance region. The channel, source region, and drain region have a region 166b and a region 166c that function as a gate. The resistance between the transistor 190 and the gate electrode 191 can be reduced. High field-effect mobility.

[0256] In addition, in the manufacturing process of the transistor 190, the conductive film 17 4, and a conductive film 170 and a conductive film 172 which function as a source electrode and a drain electrode. Therefore, in the transistor 190, the conductive film 174 and the conductive film 17 The conductive film 174 and the conductive film 170 and the conductive film 172 do not overlap each other. As a result, it is possible to use a large-area substrate as the substrate 162. When the conductive film 170 is provided, the signal delay in the conductive film 172 and the conductive film 174 is reduced. It is possible.

[0257] In the transistor 190, the conductive films 170, 172, and 174 By adding a rare gas element to the oxide semiconductor film 166 using the mask, a rare gas element having oxygen vacancies can be formed. Furthermore, the region having oxygen vacancies is in contact with the insulating film 176 containing hydrogen. Therefore, hydrogen contained in the insulating film 176 diffuses into the region having oxygen vacancies, resulting in a low resistance. That is, a low resistance region can be formed in a self-aligned manner.

[0258] In addition, in the transistor described in this embodiment, a rare gas is added to the region 166b and the region 166c. By adding hydrogen, oxygen vacancies are formed and hydrogen is added. It is possible to increase the conductivity in regions 166b and 166c, and It is possible to reduce the variation in conductivity of the region 166b and the region 166c for each sensor. That is, by adding a rare gas and hydrogen to the region 166b and the region 166c, The conductivity of 166b and region 166c can be controlled.

[0259] The configuration shown in FIG. 12 will be described in detail below.

[0260] As the substrate 162, the substrate 102 described in Embodiment 1 can be used as appropriate.

[0261] The insulating film 164 can be formed using any of the materials used for the insulating film 104 in Embodiment 1 as appropriate. can be done.

[0262] The oxide semiconductor film 166 can be formed using the material for the oxide semiconductor film 106 described in Embodiment 1. and structures can be used as appropriate.

[0263] The insulating film 168 can be formed using any of the materials for the insulating film 118 described in Embodiment 1 as appropriate. can be done.

[0264] The conductive films 170, 172, and 174 may be the conductive films described in Embodiment 1. The materials shown in the conductive films 110, 112, and 114 can be used as appropriate.

[0265] The insulating film 176 is a film containing hydrogen, and is typically a nitride insulating film. For example, silicon nitride, aluminum nitride, or the like can be used.

[0266] The insulating film 178 can be formed using any of the materials for the insulating film 118 described in Embodiment 1 as appropriate. can be done.

[0267] <Configuration 6 of Semiconductor Device> Next, another configuration of the semiconductor device will be described with reference to FIG.

[0268] 14A to 14C are top views and diagrams of a transistor 191 included in a semiconductor device. 14A is a top view of the transistor 191, and FIG. 14B is a cross-sectional view of the transistor 191. 14(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 14(A), and FIG. 14(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. FIG. 1 is a cross-sectional view taken along the dashed dotted line X1-X2.

[0269] The transistor 191 illustrated in FIG. 14 includes a conductive film 170, a conductive film 172, and a conductive film 174. The insulating film 164 is a nitride insulating film 165. The insulating film 164a and the oxide insulating film 164b are stacked in layers. It is similar to the transistor 190 and has the same effect.

[0270] First, the conductive films 170, 172, and 174 will be described.

[0271] The conductive film 170 is formed by laminating a conductive film 170a, a conductive film 170b, and a conductive film 170c in this order. The conductive film 170a and the conductive film 170c cover the surface of the conductive film 170b. That is, the conductive film 170a and the conductive film 170c serve as protective films for the conductive film 170b. It works.

[0272] Similar to the conductive film 170, the conductive film 172 includes a conductive film 172a, a conductive film 172b, and a conductive film 172c. The conductive film 172a and the conductive film 172c are laminated in this order, and the conductive film 172a and the conductive film 172c are It covers the surface of 172b.

[0273] Similar to the conductive film 170, the conductive film 174 includes a conductive film 174a, a conductive film 174b, and a conductive film 174c. The conductive film 174a and the conductive film 174c are laminated in this order, and the conductive film 174a and the conductive film 174c are It covers the surface of 174b.

[0274] The conductive films 170a, 172a, and 174a may be the same as those described in Embodiment 1. Similarly to the conductive film 110a, the conductive film 112a, and the conductive film 114a, the conductive film 170b, the conductive film The metal elements contained in the conductive film 172b and the conductive film 174b are diffused into the oxide semiconductor film 166. A material that prevents this can be used appropriately.

[0275] The conductive films 170b, 172b, and 174b may be the same as those described in Embodiment 1. Similar to the conductive films 110b, 112b, and 114b, a low-resistance material is used as appropriate. It is possible.

[0276] The conductive films 170c, 172c, and 174c may be the same as those described in Embodiment 1. The conductive film 170b, the conductive film 110c, the conductive film 112c, and the conductive film 114c are The conductive film 172b and the conductive film 174b are formed using a film in which the metal elements contained therein are passivated. As a result, the conductive film 170b, the conductive film 172b, and the conductive film 174b The metal element contained in the insulating film 176 moves to the oxide semiconductor film 166 in the process of forming the insulating film 176. This can prevent this from happening.

[0277] Next, the insulating film 164 in which the nitride insulating film 164a and the oxide insulating film 164b are stacked is and explain.

[0278] The nitride insulating film 164a and the oxide insulating film 164b can be formed by the same method as those described in Embodiment 1. The materials shown in the nitride insulating film 104a and the oxide insulating film 104b can be used as appropriate. .

[0279] <Configuration 7 of Semiconductor Device> Next, another configuration of the semiconductor device will be described with reference to FIGS.

[0280] 15A to 15C are top views and diagrams of a transistor 192 included in a semiconductor device. 15A is a top view of the transistor 192, and FIG. 15B is a cross-sectional view of the transistor 192. 15(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 15(A), and FIG. 15(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. FIG. 1 is a cross-sectional view taken along the dashed dotted line X1-X2.

[0281] The transistor 192 illustrated in FIG. 15 is characterized in that the oxide semiconductor film 166 has a multilayer structure. Specifically, the oxide semiconductor film 166 is formed by 167a, an oxide semiconductor film 167b in contact with the oxide semiconductor film 167a, and an oxide semiconductor The acid in contact with the film 167b, the conductive film 170, the conductive film 172, the insulating film 168, and the insulating film 176 The other configurations are the same as those of the transistor 190. It has the same effect.

[0282] The oxide semiconductor films 167a, 167b, and 167c are The oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107c described in Embodiment 1 are the same as those described in Embodiment 1, respectively. The material and crystal structure shown in the compound semiconductor film 107c can be used appropriately.

[0283] The oxide semiconductor films 167a and 167b are less likely to have oxygen vacancies than the oxide semiconductor films 167a and 167b. The oxide semiconductor film 167c is provided in contact with the upper and lower surfaces of the oxide semiconductor film 167b. By doing so, oxygen vacancies in the oxide semiconductor film 167b can be reduced. The oxide semiconductor film 167b contains one or more metal elements constituting the oxide semiconductor film 167b. The oxide semiconductor film 167a and the oxide semiconductor film 167c are in contact with each other. 7a and the oxide semiconductor film 167b, and the interface between the oxide semiconductor film 167b and the oxide semiconductor film 16 The interface state density at the interface with the oxide semiconductor film 167b is extremely low. It is possible to reduce the oxygen vacancies contained therein.

[0284] Furthermore, by providing the oxide semiconductor film 167a, the threshold voltage of the transistor and the like can be reduced. Therefore, the variation in the electrical characteristics can be reduced.

[0285] In addition, the oxide semiconductor film 167b contains one or more metal elements. Since the oxide semiconductor film 7c is provided in contact with the oxide semiconductor film 167b, the oxide semiconductor film 167b and the oxide semiconductor film 7c are At the interface with the compound semiconductor film 167c, scattering of carriers is unlikely to occur, and the field effect of the transistor is The resultant mobility can be increased.

[0286] The oxide semiconductor films 167a and 167c are formed between the insulating film 164 and the insulating film 165. The constituent elements of the film 168 or the constituent elements of the conductive films 170 and 172 are oxide semiconductor films. 167b and acts as a barrier film to prevent impurities from being mixed into the It also works.

[0287] From the above, the transistor described in this embodiment has electrical characteristics such as threshold voltage. This is a transistor with reduced variation.

[0288] FIG. 16 shows a transistor having a different structure from that shown in FIG.

[0289] 16A to 16C are top views and diagrams of a transistor 193 included in a semiconductor device. 16A is a top view of the transistor 193, and FIG. 16B is a cross-sectional view of the transistor 193. 16(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 16(A), and FIG. 16(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. FIG. 1 is a cross-sectional view taken along the dashed dotted line X1-X2.

[0290] In a transistor 193 illustrated in FIG. 16, an oxide semiconductor film 166 is formed between the insulating film 164 and the The oxide semiconductor film 167b in contact with the insulating film 168 and the oxide semiconductor film 167b in contact with the insulating film 168 are The other configuration may be the same as that of the transistor 19. It is the same as 0 and has the same effect.

[0291] <Configuration 8 of semiconductor device> Next, another configuration of the semiconductor device will be described with reference to FIG.

[0292] 17A to 17C are top views and diagrams of a transistor 194 included in a semiconductor device. 17A is a top view of the transistor 194, and FIG. 17B is a cross-sectional view of the transistor 194. 17(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 17(A), and FIG. 17(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. FIG. 1 is a cross-sectional view taken along the dashed dotted line X1-X2.

[0293] The transistor 194 illustrated in FIG. 17 overlaps an oxide semiconductor film 166 with an insulating film 164 interposed therebetween. That is, the conductive film 181 is a gate electrode. The transistor 194 is a transistor with a dual gate structure. .

[0294] The conductive film 174 and the conductive film 181 are not connected to each other, and different potentials are applied to them. The threshold voltage of the transistor 194 can be controlled. In this way, the conductive film 174 and the conductive film 181 are connected through the opening 183, and the same potential is applied. This reduces the initial characteristic variations, suppresses deterioration in the -GBT stress test, and It is possible to suppress the fluctuation of the on-current rising voltage in the drain voltage. In the compound semiconductor film 166, the area in which carriers flow is large in the film thickness direction. As a result, the on-current of the transistor 194 increases. , and the field-effect mobility is high. The transistor channel length can be reduced to less than 2.5 μm, or 1. By setting the thickness to 45 μm or more and 2.2 μm or less, the on-current is further increased and the field effect is This can increase the fruit mobility.

[0295] <Configuration of semiconductor device 9> Next, another configuration of the semiconductor device will be described with reference to FIGS.

[0296] 25A to 25C are top views of a transistor 150A included in a semiconductor device. 25A is a top view of a transistor 150A, and FIG. 25B is a cross-sectional view thereof. 25(A) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 25(A), and FIG. 25(C) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 25(A). 26(A) to 26(C) are cross-sectional views taken along the dashed line X1-X2. 26A and 26B show a top view and a cross-sectional view of a transistor 190A included in the semiconductor device. 26(B) is a top view of the transistor 190A, and FIG. 26(B) is a top view of the transistor 190A along the dashed line Y1-Y2 in FIG. 26(C) is a cross-sectional view taken along the dashed line X1-X2 in FIG. 26(A). do.

[0297] The transistor 150A shown in FIG. 25 is a modification of the transistor 150 shown in FIG. 25. The shape of the insulating film 108 of the transistor 150 is different from that of the insulating film 108 of the transistor 150. In the capacitor 150A, the insulating film 108 is separated into islands. It is similar to the transistor 150 and has the same effect.

[0298] The transistor 190A shown in FIG. 26 is a modification of the transistor 190 shown in FIG. 26. The shape of the insulating film 168 of the transistor 190 is different from that of the insulating film 168 of the transistor 190. In the star 190A, the insulating film 168 is separated into islands. , transistor 190 and has the same effect.

[0299] The insulating film 108 is separated into islands, whereby the oxide semiconductor film 106, the conductive film 110, and the conductive film 110 are separated into islands. Therefore, the contact area between the oxide semiconductor film 106 and the conductive film 112 can be increased. The contact resistance between the conductive film 110 and the conductive film 112 can be reduced. By separating the oxide semiconductor film 166 into islands, the oxide semiconductor film 166 can be connected to the conductive film 170 and the conductive film 172. Therefore, the contact area between the oxide semiconductor film 166 and the conductive film 170 can be increased. The contact resistance between the conductive film 172 and the transistor 1 shown in FIG. 50 or the insulating film 108 or the insulating film 168 as in the transistor 190 shown in FIG. When a structure in which the oxide semiconductor film 106 or the oxide semiconductor film 16 is not separated into islands is used, The outer periphery of the insulating film 108 or 168 may be covered with the insulating film 108 or 168. In the case of the structure, impurities that may enter the oxide semiconductor film 106 or the oxide semiconductor film 166 are suppressed. In addition, when the insulating film 108 is not separated into islands, the insulating film 108 is not separated into islands. the conductive film 114 functioning as a source electrode, the conductive film 110 functioning as a drain electrode, and The conductive film 112 that functions as a conductive layer has a structure in which at least a part of the conductive film 112 is formed on the same plane. In addition, when the insulating film 168 is not separated into islands, the conductive film 174 serving as a gate electrode and the insulating film 168 are formed in a region corresponding to the insulating film 168. The conductive film 170 functioning as a source electrode and the conductive film 172 functioning as a drain electrode are , the structure is such that at least a portion of the structure is formed on the same plane.

[0300] <Configuration 10 of Semiconductor Device> Next, another configuration of the semiconductor device will be described with reference to FIG.

[0301] FIG. 38A is a cross-sectional view of a transistor 190B included in a semiconductor device. 38(B) shows the thickness of the oxide semiconductor film 166 when an impurity element is added thereto. 38A and 38B. The cross-sectional views in the direction are shown in FIG. 12(A) and FIG. 12(B). Since it is the same as the cross-sectional view, the explanation will be omitted here.

[0302] The transistor 190B shown in FIG. 38(A) is a modification of the transistor 190 shown in FIG. For example, the conductive films 170, 172, and 174 included in the transistor 190 are The structure of the transistor 190B shown in FIG. 90 has different cross-sectional shapes of the insulating film 168, the insulating film 176, and the insulating film 178. In the transistor 190B shown in FIG. 38(A), the conductive film 170, the conductive film 172, and The conductive film 174 has a two-layer laminate structure, and the insulating film 168, the insulating film 176, and the insulating film 174 are laminated. The edge of the insulating film 178 has a curvature in part. It is the same as 0 and has the same effect.

[0303] The conductive film 170 has a laminated structure of a conductive film 170d and a conductive film 170e. , a conductive film 172d and a conductive film 172e are laminated together, and the conductive film 174 is a conductive film 174d The conductive film 170d, the conductive film 174d, and the conductive film 174e are stacked. Examples of 2d include tantalum nitride, titanium nitride, molybdenum nitride, and tungsten nitride. A metal nitride film such as the above can be used.

[0304] The conductive films 170e, 172e, and 174e are made of a low-resistance metal material. The low resistance metal material can be, for example, aluminum, copper, The conductive film 170e, the conductive film 172e, and the conductive film 174e may be made of silver. In addition to the low-resistance metal materials mentioned above, tungsten or molybdenum may also be used.

[0305] In the conductive film 170, the end of the conductive film 170d protrudes outward more than the end of the conductive film 170e. In addition, in the conductive film 172, the conductive film 172d is thicker than the conductive film 172e. The conductive film 174 has a shape in which the end portion thereof protrudes outward. The conductive film 170 and the conductive film 174d have a shape in which the end portion thereof protrudes outward. The conductive film 172 and the conductive film 174 have a two-layer structure, and the lower conductive film protrudes. By forming the lower conductive film in a protruding shape, it is possible to In some cases, the underlying conductive film can suppress the passage of impurities.

[0306] The conductive films 170, 172, and 174 can be processed by, for example, The dry etching method is used to form the conductive film 170 and the conductive When processing the insulating film 168, a part of the edge of the insulating film 168 is removed. In addition, the shape of the end of the insulating film 168 may have a curvature. When the insulating film 168 has a shape having the insulating film 176 and the insulating film 17 The shape of the insulating film 168 may also have a curvature at a part of the edge.

[0307] Next, referring to FIG. 38B, the oxide semiconductor of the transistor 190B shown in FIG. 38A is The conceptual diagram in the film thickness direction when an impurity element is added to the film 166 is explained below. Reveal.

[0308] In FIG. 38B, the oxide semiconductor film 166 includes a region 166x and a region 166y. When the oxide semiconductor film 166 is a crystalline oxide semiconductor film, for example, the region 166y is The crystallinity is higher than that of region 166x. The difference in crystallinity is due to the addition of impurity elements. This is because the 166x is damaged and its crystallinity is reduced.

[0309] <Method 3 for manufacturing semiconductor device> Next, a manufacturing method of the transistor 190 shown in FIG. 12 will be described with reference to FIGS. 18 to 20. I will explain.

[0310] As shown in FIG. 18(A), an insulating film 164 is formed on a substrate 162.

[0311] The insulating film 164 can be formed by the formation method of the insulating film 104 described in Embodiment 1 as appropriate. do.

[0312] Next, as shown in FIG. 18B, an oxide semiconductor film 166 is formed over the insulating film 164. Next, an insulating film 168 is formed over the insulating film 164 and the oxide semiconductor film 166. The conductive film 166 and the insulating film 168 are the same as those of the oxide semiconductor film 106 and the insulating film 168 described in Embodiment 1, respectively. The method for forming the insulating film 108 can be appropriately used.

[0313] Next, as shown in FIG. 19(A), a mask is formed on the insulating film 168 by a lithography process. After the formation, part of the insulating film 168 is etched to expose part of the oxide semiconductor film 166. The openings 180a and 180b are formed.

[0314] Next, as shown in FIG. 19B, a conductive film Form 169.

[0315] The conductive film 169 can be formed by the method for forming the conductive film 109 described in Embodiment 1 as appropriate. do.

[0316] Next, as shown in FIG. 19(C), a mask is formed on the conductive film 169 by a lithography process. After forming the conductive film 169 111 , the conductive film 169 is immersed in an etching solution and / or etching gas 167 . The conductive film 170, the conductive film 172, and the conductive film 174 are formed by exposing the conductive film 170 to light.

[0317] The conductive film 169 is etched by wet etching or / and dry etching. The chiming method can be used as appropriate.

[0318] The conductive films 170, 172, and 174 may be formed by the following method instead of the above method. It may also be formed by electrolytic plating, printing, ink jetting, or the like.

[0319] Next, as shown in FIG. 19(D), the oxide semiconductor film 166 is removed while the mask 111 is left. A rare gas is added as the impurity element 177 to the oxide semiconductor film. The impurity element 177 is doped into the region not covered with 111. As a result, oxygen vacancies are formed in the oxide semiconductor film.

[0320] The impurity element 177 can be added by the same method as that of adding the impurity element 117 described in Embodiment 1. The method can be used as appropriate.

[0321] Here, when the impurity element 177 is added to the oxide semiconductor film 166, 21 shows a conceptual diagram of a region to which an impurity element is added. This is an enlarged view of the vicinity.

[0322] As shown in FIG. 21(A), the region where the impurity element 177 is added is covered with the insulating film 164, the oxide semiconductor, and the like. The oxide semiconductor film 166 may be formed on the conductive film 166 and the insulating film 168. In the depth direction of the region where the doped region is exposed, the end 195 of the doped region is located in the insulating film 164. do.

[0323] Alternatively, as shown in FIG. 21B, the region to which the impurity element 177 is added is formed in the oxide semiconductor film. In some cases, the insulating film 166 and the insulating film 168 are formed on the oxide semiconductor film 166. In the depth direction of the doped region, an end 196 of the doped region is formed between the insulating film 164 and the oxide semiconductor film Located at the interface of 166.

[0324] Alternatively, as shown in FIG. 21C, the region to which the impurity element 177 is added is formed in the oxide semiconductor film. In some cases, the insulating film 166 and the insulating film 168 are formed on the oxide semiconductor film 166. In the depth direction of the doped region, an end portion 197 of the doped region is located in the oxide semiconductor film 166. do.

[0325] After that, the mask 111 is removed as shown in FIG.

[0326] Note that here, the impurity element 177 is added to the oxide semiconductor film 166 using the mask 111. After removing the mask 111, the conductive film 170, the conductive film 172, and the conductive film 17 The impurity element 177 may be added to the oxide semiconductor film 166 using the mask 4.

[0327] In addition, the step of forming the conductive film 169, the step of etching the conductive film 169, or the subsequent step of forming the insulating film 1 In the formation process of the oxide semiconductor film 166, damage occurs and oxygen vacancies are formed. In this case, the impurity element 177 does not need to be added.

[0328] Next, as shown in FIG. 20B, the oxide semiconductor film 166, the insulating film 168, and the conductive film 17 0, an insulating film 176 is formed on the conductive film 172 and the conductive film 174, and an insulating film 176 is formed on the insulating film 176. A velum 178 may be formed.

[0329] The insulating film 176 can be formed by a sputtering method, a CVD method, a vacuum deposition method, a pulse deposition method, or the like. Laser deposition (PLD) method, etc. Silane and ammonia, or silane and nitrogen A silicon nitride film containing hydrogen is formed by the plasma CVD method using the above as a raw material gas. In addition, by using the plasma CVD method, the oxide semiconductor film 166 is not damaged. As a result, oxygen vacancies can be formed in the oxide semiconductor film 166.

[0330] Since the insulating film 176 contains hydrogen, the impurity element When the region to which oxygen is added comes into contact with the insulating film 176, the hydrogen contained in the insulating film 176 is converted into oxygen. The impurity element is added to the region of the nitride semiconductor film. The oxygen vacancies in the region are used to form low-resistance regions in the oxide semiconductor film 166. Specifically, the regions 166b and 166c shown in FIG. Note that the region 166c is formed by adding an element to the oxide semiconductor film 166 through the insulating film 168. Therefore, the concentration of the impurity element is lower than that of the region 166b.

[0331] Note that by forming the insulating film 176 under heating, hydrogen contained in the oxide semiconductor film is However, when hydrogen migrates to the oxygen vacancy, the hydrogen becomes energetically stable. This makes it difficult for hydrogen to be released from the oxygen vacancies. In addition, due to the interaction between oxygen vacancies and hydrogen, Electrons, which are carriers, are generated. For this reason, the insulating film 176 is formed while heating. This makes it possible to form a low resistance region with little fluctuation in conductivity.

[0332] After that, heat treatment is performed to further increase the conductivity of the region where the impurity element 177 is added. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate strain point, or 250° C. ℃ or more and 450℃ or less, or 300℃ or more and 450℃ or less. It is possible to increase the conductivity and reduce the fluctuation of the conductivity in the low resistance region. Cut.

[0333] The insulating film 178 can be formed by appropriately using the method for forming the insulating film 164 and the insulating film 168. can.

[0334] In addition, the substrate placed in the evacuated processing chamber of the plasma CVD device is heated to 180°C or higher. The temperature is kept at 280°C or below, or between 200°C and 240°C, and the raw material gas is introduced into the processing chamber. The pressure in the processing chamber should be between 100 Pa and 250 Pa, or between 100 Pa and 200 Pa. a or less, and the electrode installed in the processing chamber is 0.17 W / cm 2 More than 0.5W / cm 2 below , or 0.25 W / cm 2 More than 0.35W / cm 2The following high frequency power supply conditions are met: Therefore, a silicon oxide film or a silicon oxynitride film capable of releasing oxygen by heat treatment is used. The insulating film 178 can be formed of a silicon film.

[0335] Through the above steps, a transistor can be manufactured.

[0336] <Method 4 for manufacturing semiconductor device> A method for manufacturing the transistor 191 shown in FIG. 14 will be described. The conductive film 170c included in the conductive film 170, the conductive film 172, and the conductive film 174 of the capacitor 191; Steps for forming the conductive films 172c and 174c and adding an impurity element to the oxide semiconductor film 166 The process of adding 177 will be described.

[0337] 18 and 19(A) to 19(C), an insulating film 164 is formed on a substrate 162. , an oxide semiconductor film 166, an insulating film 168, a conductive film 170, a conductive film 172, a conductive film 174, and forming a mask 111.

[0338] Next, as shown in FIG. 19D, an impurity element 177 is added to the oxide semiconductor film 166. do.

[0339] Next, the mask 111 is removed.

[0340] Next, the conductive film 170 included in each of the conductive film 170, the conductive film 172, and the conductive film 174 b, the conductive film 172b and the conductive film 174b are exposed to plasma generated in a reducing atmosphere, and the conductive film 172b and the conductive film 174b are The oxides on the surfaces of the film 170b, the conductive film 172b, and the conductive film 174b are reduced. The conductive film 170b, the conductive film 172b, and the conductive film 172a are heated at a temperature of 00° C. or higher and 400° C. or lower. Next, the conductive film 170b, the conductive film 172b, and the conductive film 174b are exposed to silane. By exposing the conductive material to plasma generated in an atmosphere containing nitrogen, such as ammonia or nitrogen, The conductive film 170c, the conductive film 172c, and the conductive film 174c are made of CuSi x N y (x>0, y>0).

[0341] In addition, when exposed to plasma generated in an atmosphere containing nitrogen such as ammonia or nitrogen, In this case, the oxide semiconductor film 166 is formed in an atmosphere containing nitrogen such as ammonia or nitrogen. Nitrogen and / or hydrogen are added to the oxide semiconductor film 166 due to the exposure to plasma. is possible.

[0342] Note that the mask 111 is removed before the impurity element 177 is added to the oxide semiconductor film 166. The conductive film 170c and the conductive film 170c included in the conductive film 170, the conductive film 172, and the conductive film 174 are 172c and a conductive film 174c may be formed.

[0343] After that, the transistor 191 can be manufactured through the process of FIG.

[0344] <Method 5 for manufacturing semiconductor device> Another method for manufacturing the transistor 190 shown in FIG. 12 will be described. The step of adding elements and the step of forming the insulating film 176 will be described with reference to FIG.

[0345] 18 and 19(A) to 19(C), an insulating film 164 is formed on a substrate 162. , an oxide semiconductor film 166, an insulating film 168, a conductive film 170, a conductive film 172, a conductive film 174, and a mask 111 is formed. After that, as shown in FIG. 22(A), the mask 111 is removed. Remove.

[0346] Next, as shown in FIG. 22(B), the oxide semiconductor film 166, the insulating film 168, and the conductive film 17 0, an insulating film 176 is formed over the conductive film 172 and the conductive film 174, and then the conductive film 170, The oxide semiconductor film 172 is formed on the insulating film 176 by using the conductive films 172 and 174 as masks. An impurity element 177 is added to 166 .

[0347] Next, as shown in FIG. 22(C), an insulating film 178 may be formed. , transistor 190 can be fabricated.

[0348] The transistor described in this embodiment includes the conductive films 170, 172, and 174. Since there is no overlap, it is possible to reduce the parasitic capacitance and the on-current is large. The transistor described in this embodiment can stably form a low-resistance region; Compared to conventional devices, the on-state current is improved and the variation in the electrical characteristics of the transistor is reduced.

[0349] As described above, the structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiments. They can be used in combination.

[0350] (Embodiment 3) In this embodiment mode, one mode of a semiconductor device and a manufacturing method of the semiconductor device will be described with reference to FIGS. 4 will be used to explain.

[0351] <Configuration 11 of Semiconductor Device> FIG. 23 shows a transistor 150 included in the semiconductor device and a circuit connected to the transistor 150. 1 shows the structure of a capacitance element 159.

[0352] 23A and 23B show a transistor 150 and a capacitor included in a semiconductor device. 23A shows a top view and a cross-sectional view of the transistor 150 and the capacitor 159. 23(B) is a cross-sectional view taken along the dashed line X1-X2 in FIG. 23(A); 23A is a cross-sectional view of the cross section taken along the dashed line X3-X4. Therefore, the substrate 102, the insulating film 104, the insulating film 108, the insulating film 116, the insulating film 118, and the insulating film Numbers such as 122 are omitted.

[0353] The transistor 150 shown in FIG. 23 is the same as the transistor 150 described in the first embodiment. It has a structure.

[0354] The capacitor 159 includes an oxide semiconductor film 156 over the insulating film 104 and an oxide semiconductor film The insulating film 118 is in contact with the insulating film 156 , and the conductive film 124 is on the insulating film 118 .

[0355] An insulating film 122 is formed on the insulating film 118. The insulating film 116, the insulating film 118, and the insulating film 122 are In the opening 142a of the insulating film 122, the conductive film 124 contacts the conductive film 112. 08, the insulating film 116, the insulating film 118, and the opening 142b of the insulating film 122, The film 124 contacts the insulating film 118 .

[0356] The insulating film 122 may be made of a material such as polyimide, acrylic, polyamide, or epoxy. The insulating film 122 has a thickness of 500 nm or more and 10 μm or less. It is preferable that there is.

[0357] The conductive film 124 may be formed of indium tin oxide or indium oxide containing tungsten oxide. Indium zinc oxide containing tungsten oxide, Indium oxide containing titanium oxide Indium tin oxide containing titanium oxide, indium zinc oxide, indium oxide containing silicon oxide The light-transmitting conductive material such as indium tin oxide can be used.

[0358] The conductive film 124 may be made of silver, aluminum, chromium, copper, tantalum, titanium, molybdenum, or the like. It can be formed using a metal element that reflects light, such as iridium or tungsten. Furthermore, a film formed using a metal element that reflects light and a light-transmitting conductive material Alternatively, the film may be formed by laminating films formed using the above.

[0359] The oxide semiconductor film 156 has a light-transmitting property because it is formed at the same time as the oxide semiconductor film 106. In addition, the impurity element is added to the region 106b in the oxide semiconductor film 106. Therefore, the oxide semiconductor film 156 has conductivity.

[0360] When the conductive film 124 is formed using a light-transmitting conductive material, the capacitor 15 Therefore, by providing the capacitor element 159 in the pixel of the display device, It is possible to increase the aperture ratio in the

[0361] <Configuration 12 of Semiconductor Device> FIG. 24 shows a transistor 190 included in the semiconductor device and a 1 shows the structure of a capacitance element 199.

[0362] 24A and 24B show a transistor 190 and a capacitor included in a semiconductor device. 24A shows a top view and a cross-sectional view of the transistor 190 and the capacitor 199. 24(B) is a cross-sectional view taken along the dashed line X1-X2 in FIG. 24(A); 24(A) is a cross-sectional view of the cross section taken along the dashed line X3-X4. Therefore, the substrate 162, the insulating film 164, the insulating film 168, the insulating film 176, the insulating film 178, the insulating film 182 and others are omitted.

[0363] The transistor 190 shown in FIG. 24 is the same as the transistor 190 described in the second embodiment. It has a structure.

[0364] The capacitor 199 includes an oxide semiconductor film 198 over the insulating film 164 and an oxide semiconductor film The insulating film 176 is in contact with the insulating film 198 , and the conductive film 184 is on the insulating film 176 .

[0365] An insulating film 182 is formed on the insulating film 178. The insulating film 176, the insulating film 178, and the insulating film 182 are In the opening 182a of the insulating film 182, the conductive film 184 contacts the conductive film 172. 68, the insulating film 176, the insulating film 178, and the opening 182b of the insulating film 182. The film 184 contacts the insulating film 176 .

[0366] The insulating film 182 can be formed using the same material as the insulating film 122 shown in FIG.

[0367] The conductive film 184 can be formed using the material of the conductive film 124 shown in FIG. 23B as appropriate.

[0368] The oxide semiconductor film 198 is formed through the same process as the oxide semiconductor film 166. In addition, like the region 166b included in the oxide semiconductor film 166, Therefore, the oxide semiconductor film 198 has conductivity.

[0369] When the conductive film 184 is formed using a light-transmitting conductive material, the capacitor 19 Therefore, by providing the capacitor element 199 in the pixel of the display device, It is possible to increase the aperture ratio in the

[0370] In addition, one electrode of the capacitor and a gate electrode of the capacitor are formed in the same process as the oxide semiconductor film included in the transistor. Therefore, the number of masks can be increased. In addition, the transistor and the capacitor can be formed at the same time.

[0371] As described above, the structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiments. They can be used in combination.

[0372] (Fourth embodiment) In this embodiment, a structure of an oxide semiconductor film included in a semiconductor device of one embodiment of the present invention will be described. This will be explained in detail below.

[0373] First, possible structures of the oxide semiconductor film will be described below.

[0374] <Structure of oxide semiconductors> Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include CAAC-OS, polycrystalline oxide semiconductors, and microcrystalline oxide semiconductors. Examples include amorphous oxide semiconductors and amorphous oxide semiconductors.

[0375] From another point of view, oxide semiconductors are classified into amorphous oxide semiconductors and other crystalline oxides. Crystalline oxide semiconductors are divided into single-crystal oxide semiconductors, CAAC- Examples of such oxide semiconductors include OS, polycrystalline oxide semiconductors, and microcrystalline oxide semiconductors.

[0376] <caac-os> First, let me explain about CAAC-OS. Axis-Aligned Nanocrystals It can also be done as follows.

[0377] CAAC-OS is an oxide having multiple crystal parts (also called pellets) aligned along the c-axis. It is a type of semiconductor.

[0378] Transmission Electron Microscope (TEM) A combined analysis image (high resolution) of the bright-field image and diffraction pattern of CAAC-OS was obtained by using a microscope. When observing a high-resolution TEM image, multiple pellets can be confirmed. On the other hand, high-resolution TEM images reveal the boundaries between pellets, i.e., grain boundaries. Therefore, the CAAC-OS is not clearly characterized by the grain boundaries. It can be said that the resulting decrease in electron mobility is unlikely to occur.

[0379] Below, we will explain the CAAC-OS observed by TEM. 1 shows a high-resolution TEM image of a cross section of CAAC-OS observed from a direction approximately parallel to the sample surface. For high-resolution TEM imaging, spherical aberration correction is required. The spherical aberration correction function was used to obtain high-resolution TEM images. , specifically referred to as a Cs-corrected high-resolution TEM image. Cs-corrected high-resolution TEM images can be obtained, for example, This is performed using an atomic resolution analytical electron microscope such as the JEM-ARM200F manufactured by JEOL Ltd. It is possible.

[0380] An enlarged Cs-corrected high-resolution TEM image of region (1) in Figure 34(A) is shown in Figure 34(B). From Figure 34(B), it can be seen that the metal atoms are arranged in layers in the pellet. The arrangement of each metal atom layer is determined by the surface on which the CAAC-OS film is to be formed (also referred to as the surface on which the film is to be formed). Or it reflects the unevenness of the top surface and is parallel to the surface on which the CAAC-OS is formed or the top surface.

[0381] As shown in Figure 34(B), CAAC-OS has a characteristic atomic arrangement. ) shows the characteristic atomic arrangement with auxiliary lines. ) the size of each pellet is about 1 nm to 3 nm, and the size of each pellet is about 1 nm to 3 nm. It can be seen that the size of the gap caused by the tilt is about 0.8 nm. The pellets may also be referred to as nanocrystals (nc).

[0382] Here, based on the Cs-corrected high-resolution TEM image, the pellets of CAAC-OS on the substrate 5120 were The layout of the 5100 is shown diagrammatically as a stack of bricks or blocks. (See FIG. 34(D)). Between the pellets observed in FIG. 34(C), The portion where the tilt occurs corresponds to the area 5161 shown in FIG.

[0383] FIG. 35(A) shows the C of the plane of the CAAC-OS observed from a direction approximately perpendicular to the sample surface. s-corrected high-resolution TEM images are shown. Regions (1), (2), and (3) in Figure 35(A). ) are enlarged Cs-corrected high-resolution TEM images shown in Figure 35(B), Figure 35(C), and As shown in Figure 35(D), Figure 35(B), Figure 35(C) and Figure 35(D) show that the pellet It can be seen that the metal atoms are arranged in a triangular, quadrangular or hexagonal shape. However, no regularity is observed in the arrangement of metal atoms among different pellets.

[0384] Next, C analyzed by X-ray diffraction (XRD) For example, CAAC-O with InGaZnO4 crystals When S is subjected to structural analysis using the out-of-plane method, the results are as shown in Figure 36(A). As shown in the figure, a peak may appear at a diffraction angle (2θ) of around 31°. Since this is attributed to the (009) plane of the ZnO4 crystal, it is believed that the CAAC-OS crystal is c-axis oriented. It can be seen that the c-axis is oriented in a direction substantially perpendicular to the surface on which the film is formed or the upper surface.

[0385] In addition, in the structural analysis of CAAC-OS using the out-of-plane method, 2θ is 31 In addition to the peak around 2θ of 36°, a peak may also appear around 2θ of 36°. The peaks in the vicinity indicate that some of the CAAC-OS crystals do not have a c-axis orientation. The more preferable CAAC-OS is a structure produced by the out-of-plane method. The analysis shows a peak at 2θ around 31°, but no peak at 2θ around 36°.

[0386] On the other hand, in-pla, X-rays are incident on the CAAC-OS from a direction almost perpendicular to the c-axis. When structural analysis is performed using the NE method, a peak appears at 2θ around 56°. This peak is due to I It is attributed to the (110) plane of the nGaZnO4 crystal. In the case of CAAC-OS, 2θ is set to 5 The sample is fixed at approximately 6° and analyzed while rotating around the normal vector of the sample surface (φ axis). Even if a (φ scan) is performed, no clear peak appears as shown in Figure 36(B). On the other hand, in the case of a single crystal oxide semiconductor such as InGaZnO4, 2θ is fixed at around 56° and φ When scanned, it is assigned to a crystal plane equivalent to the (110) plane as shown in Figure 36(C). Six peaks are observed. Therefore, from the structural analysis using XRD, CAAC-OS It can be seen that the orientation of the a-axis and b-axis is irregular.

[0387] Next, we will explain the CAAC-OS analyzed by electron diffraction. For CAAC-OS with ZnO4 crystals, the probe diameter is 300 nm parallel to the sample surface. When an electron beam is incident on the sample, a diffraction pattern (selected area transmission electron diffraction) as shown in FIG. This diffraction pattern may appear due to the presence of InGaZnO4 This includes spots due to the (009) plane of the crystal. The pellets contained in the CAAC-OS have a c-axis orientation, and the c-axis faces the surface to be formed or the upper surface. On the other hand, when the probe was applied to the same sample perpendicular to the sample surface, The diffraction pattern when an electron beam with a diameter of 300 nm was incident is shown in Figure 42(B). 2(B) shows a ring-shaped diffraction pattern. It can be seen that the a-axis and b-axis of the pellets contained in CAAC-OS do not have any orientation. The first ring in FIG. 42(B) is the (010) plane of the InGaZnO4 crystal. This is thought to be due to the (100) plane and the like. This is thought to be due to the (110) surface.

[0388] In addition, the CAAC-OS is an oxide semiconductor with a low density of defect states. Defects include, for example, defects caused by impurities and oxygen vacancies. AC-OS can also be considered an oxide semiconductor with a low impurity concentration. S can also be said to be an oxide semiconductor with few oxygen vacancies.

[0389] Impurities contained in oxide semiconductors can act as carrier traps or as carrier generation sources. In addition, oxygen vacancies in an oxide semiconductor may become carrier traps or By capturing hydrogen, it may become a carrier generation source.

[0390] The impurities are elements other than the main components of the oxide semiconductor, such as hydrogen, carbon, silicon, and transition metals. For example, metal elements such as silicon are more oxidative than metal elements that constitute oxide semiconductors. Elements with strong bonding strength with the oxide semiconductor remove oxygen from the oxide semiconductor, which changes the atomic arrangement of the oxide semiconductor. In addition, heavy metals such as iron and nickel, argon, Carbon dioxide and other molecules have a large atomic radius (or molecular radius), so the atomic arrangement of oxide semiconductors This disrupts the structure and reduces the crystallinity.

[0391] In addition, oxide semiconductors with low defect state density (few oxygen vacancies) have low carrier density. Such an oxide semiconductor can be a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. CAAC-OS has a low impurity concentration and a low density of defect states. Therefore, the oxide semiconductor is likely to be a highly pure intrinsic or substantially highly pure intrinsic oxide semiconductor. A transistor using AC-OS has electrical characteristics in which the threshold voltage is negative (normal It is also called "on." It is rare for it to become a high-purity intrinsic or substantially high-purity intrinsic Oxide semiconductors have few carrier traps. The charge that is trapped takes a long time to be released and behaves like a fixed charge. Therefore, transistors using oxide semiconductors with high impurity concentrations and high defect state densities are being developed. On the other hand, transistors using CAAC-OS can have unstable electrical characteristics. The resulting transistor has little fluctuation in electrical characteristics and is highly reliable.

[0392] In addition, CAAC-OS has a low defect level density, so it is possible to generate Therefore, the carriers are less likely to be captured by the defect level. The electrical characteristics of a transistor are less susceptible to change when irradiated with visible light or ultraviolet light.

[0393] <Microcrystalline oxide semiconductor> Next, a microcrystalline oxide semiconductor will be described.

[0394] Microcrystalline oxide semiconductors have regions where crystals can be confirmed in high-resolution TEM images. The microcrystalline oxide semiconductor has a crystal structure including a region where a crystal part is clearly visible and a region where a crystal part is not clearly visible. The crystal part contained is between 1 nm and 100 nm, or between 1 nm and 10 nm in size. In particular, fine crystals of 1 nm to 10 nm or 1 nm to 3 nm are often The oxide semiconductor with nanocrystalline structure is called nc-OS (nanocrystalline silicon). nc-OS is called NC-Oxide Semiconductor. In some cases, the grain boundaries cannot be clearly identified in the TEM images. It is possible that the origin of the pellets in C-OS is the same as that of the pellets in C-OS. The crystalline part of the OS is sometimes called a pellet.

[0395] nc-OS is a material that can be used in microscopic areas (e.g., areas between 1 nm and 10 nm, especially areas between 1 nm and 10 nm). The atomic arrangement is periodic in the region of 3 nm or less. There is no regularity in the crystal orientation between the layers. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis method, nc-OS may be indistinguishable from amorphous oxide semiconductors. For example, an XRD apparatus using an X-ray beam with a diameter larger than that of the pellet is used for nc-OS. When structural analysis is performed using the out-of-plane method, the crystal plane is shown. In addition, the probe diameter ( For example, electron diffraction (also called selected area electron diffraction) is performed using an electron beam of 50 nm or more. On the other hand, for nc-OS, a halo-like diffraction pattern is observed. Nanobeam electron circuits use electron beams with a probe diameter close to the pellet size or smaller than the pellet. When the nc-OS is subjected to nanobeam electron diffraction, spots are observed. When the light is too bright, a circular (ring-shaped) area of ​​high brightness may be observed. Multiple spots may be observed within a ring-like region.

[0396] In this way, the crystal orientation between the pellets (nanocrystals) is not regular, so nc -OS with RANC (Random Aligned nanocrystals) oxide semiconductors, or NANCs (Non-Aligned Nanocrystals) The semiconductor may also be referred to as an oxide semiconductor having a structure (s).

[0397] The nc-OS is an oxide semiconductor with higher order than an amorphous oxide semiconductor. However, the density of defect states in nc-OS is lower than that in amorphous oxide semiconductors. There is no regularity in the crystal orientation between different pellets in S. Therefore, nc-OS is The defect density is higher than that of AAC-OS.

[0398] <Amorphous oxide semiconductor> Next, the amorphous oxide semiconductor will be described.

[0399] Amorphous oxide semiconductors are oxides in which the atomic arrangement within the film is irregular and does not have crystalline parts. An example is an oxide semiconductor that has an amorphous state, such as quartz.

[0400] In amorphous oxide semiconductors, no crystalline parts can be observed in high-resolution TEM images.

[0401] When structural analysis is performed on amorphous oxide semiconductors using an XRD device, out-of-p In the analysis by the Lane method, no peaks indicating crystal planes were detected. When electron diffraction is performed on a conductor, a halo pattern is observed. When nanobeam electron diffraction is performed on the sample, no spots are observed, and only a halo pattern is observed. Observed.

[0402] There are various views on amorphous structures. For example, A structure that does not have this property is called a completely amorphous structure. The distance between the nearest neighboring atoms or the second nearest neighboring atoms is also called the structure. A structure that has order at the interface but does not have long-range order is sometimes called an amorphous structure. Therefore, according to the strictest definition, an oxide semiconductor that has even a slight degree of order in its atomic arrangement is called a non-metallic oxide semiconductor. Furthermore, it cannot be called an crystalline oxide semiconductor. Therefore, since the semiconductor has crystalline parts, it cannot be called an amorphous oxide semiconductor. For example, CAAC-OS and nc-OS are used as amorphous oxide semiconductors or completely amorphous It cannot be called an oxide semiconductor.

[0403] <Amorphous-like oxide semiconductor> Note that an oxide semiconductor may have a structure between an nc-OS and an amorphous oxide semiconductor. An oxide semiconductor having such a structure is particularly called an amorphous-like oxide semiconductor (aluminum oxide). ike OS:amorphous-like Oxide Semiconducto It is called r).

[0404] In a-like OS, voids (also called voids) are observed in high-resolution TEM images. In addition, crystals can be clearly seen in high-resolution TEM images. and regions where no crystalline portions can be identified.

[0405] Because of the porosity, the a-like OS has an unstable structure. e OS has an unstable structure compared with CAAC-OS and nc-OS. This shows the structural changes caused by electron irradiation.

[0406] The samples to be irradiated with electrons were a-like OS (referred to as sample A), nc-OS (hereinafter referred to as Sample B) and CAAC-OS (hereinafter referred to as Sample C) are prepared. Both samples are In-Ga-Zn oxides.

[0407] First, high-resolution cross-sectional TEM images of each sample are acquired. It can be seen that all the materials have crystalline parts.

[0408] The determination of which part is to be regarded as one crystal part can be made as follows. For example, The unit cell of the InGaZnO4 crystal has three In-O layers and one Ga-Zn-O layer. It is known that the structure has a total of nine layers, six of which are stacked in layers in the c-axis direction. The spacing between these adjacent layers is approximately the same as the lattice spacing (also called the d value) of the (009) plane. The value is calculated to be 0.29 nm from crystal structure analysis. The areas where the spacing is 0.28 nm or more and 0.30 nm or less are considered to be InGaZnO4 crystal parts. The lattice fringes correspond to the ab plane of the InGaZnO4 crystal.

[0409] Figure 43 shows an example of investigating the average size of the crystal parts (22 to 45 locations) of each sample. However, the length of the lattice fringes mentioned above is the size of the crystal part. It can be seen that the crystalline part of ke OS grows in size according to the cumulative amount of electron irradiation. Specifically, as shown by (1) in Figure 43, the initial TEM observation showed a size of about 1.2 nm. The crystal part (also called the initial nucleus) was 4.2 × 10 8 e - / n m 2 On the other hand, in the nc-O For S and CAAC-OS, the cumulative electron irradiation dose from the start of electron irradiation was 4.2 × 10 8 e - / nm 2 It can be seen that there is no change in the size of the crystal part within the range of As shown in (2) and (3) in Figure 43, regardless of the cumulative electron dose, the nc-OS and The sizes of the crystal parts of the CAAC-OS and CAAC-OS are approximately 1.4 nm and 2.1 nm, respectively. It can be seen that...

[0410] In this way, the growth of crystalline parts can be observed in a-like OS due to electron irradiation. On the other hand, in nc-OS and CAAC-OS, the growth of the crystals by electron irradiation is almost nonexistent. In other words, a-like OS is not as good as nc-OS and CAAC- It is clear that it has an unstable structure compared to the OS.

[0411] In addition, due to its porosity, a-like OS is more flexible than nc-OS and CAAC-OS. Specifically, the density of a-like OS is lower than that of a single crystal of the same composition. The density of the nc-OS is 78.6% or more and less than 92.3% of that of the normal crystal. The density of C-OS is 92.3% or more but less than 100% of the density of a single crystal of the same composition. It is difficult to form a film of an oxide semiconductor having a crystal density of less than 78%.

[0412] For example, in an oxide semiconductor having an atomic ratio of In:Ga:Zn=1:1:1, The density of single-crystal InGaZnO4 with a rhombohedral crystal structure is 6.357 g / cm 3 It becomes. For example, in an oxide semiconductor that satisfies the atomic ratio of In:Ga:Zn=1:1:1, The density of a-like OS is 5.0 g / cm 3 More than 5.9g / cm 3 It will be less than For example, in an oxide semiconductor having an atomic ratio of In:Ga:Zn=1:1:1, , the density of nc-OS and the density of CAAC-OS are 5.9 g / cm 3 More than 6.3g / cm 3 It will be less than.

[0413] In some cases, single crystals with the same composition do not exist. In such cases, crystals with different compositions may be used in any proportion. By combining single crystals with the desired composition, the density equivalent to that of a single crystal can be estimated. The density corresponding to a single crystal of a desired composition can be obtained by combining single crystals of different compositions. The density should be as low as possible. It is preferable to estimate by combining different types of single crystals.

[0414] As described above, oxide semiconductors have various structures, each of which has various characteristics. The oxide semiconductor may be, for example, an amorphous oxide semiconductor, an a-like OS, or a microcrystalline oxide semiconductor. The layer may be a laminated film containing two or more of a compound semiconductor and a CAAC-OS.

[0415] <Film formation model> An example of a film formation model for CAAC-OS and nc-OS will be described below.

[0416] FIG. 44(A) shows a process of forming a CAAC-OS film by sputtering. Schematic diagram of the inside of the membrane chamber.

[0417] The target 5130 is glued to a backing plate. A plurality of magnets are arranged at positions facing the target 5130 through the magnets. The magnetic field is generated by a number of magnets. The sputtering method used is called magnetron sputtering.

[0418] The substrate 5120 is disposed so as to face the target 5130, and the distance therebetween is d( The target-substrate distance (also called the TS distance) is preferably 0.01 m or more and 1 m or less. The thickness of the film deposition chamber is 0.02m or more and 0.5m or less. oxygen, argon, or a gas mixture containing 5% or more by volume of oxygen) and The pressure is controlled to 1 Pa or more and 100 Pa or less, preferably 0.1 Pa or more and 10 Pa or less. By applying a voltage above a certain level to the target 5130, a discharge begins and plasma is generated. It is confirmed that a high density plasma region is generated near the target 5130 by the magnetic field. In the high density plasma region, the deposition gas is ionized, and ions 5101 The ions 5101 are, for example, positive ions of oxygen (O + ) and argon cations ( Ar + ) etc.

[0419] Here, the target 5130 has a polycrystalline structure having a plurality of crystal grains, and The crystal grains include cleavage planes. The crystal structure of InGaZnO4 is shown in Fig. 45(A). This is the structure of InGaZnO4 crystals observed from the outside. In the two Ga-Zn-O layers, the oxygen atoms in each layer are arranged in close proximity. The negative charge of the oxygen atom makes it possible to separate two adjacent atoms. Repulsion occurs between the Ga-Zn-O layers. As a result, the InGaZnO4 crystals are The cleavage plane is located between the two Ga-Zn-O layers.

[0420] Ions 5101 generated in the high-density plasma region are applied to the target 5130 side by the electric field. The cleavage plane is accelerated and eventually collides with the target 5130. At this time, flat or pellet-like particles are formed from the cleavage plane. Pellets 5100a and 5100b, which are pellet-shaped sputtered particles, are peeled off and struck. The pellets 5100a and 5100b are the particles of the ions 5101. The impact of a collision can cause distortion in the structure.

[0421] The pellet 5100a is a flat plate or pellet having a triangular, for example, equilateral triangular, plane. The pellet 5100b is a sputtered particle having a hexagonal shape, for example, a regular hexagonal plane. The pellets 5100a and 5100b are sputtered particles in the form of plates or pellets. Sputter particles in the form of flat or pellets, such as pellets 5100b, are collectively called pellets. The planar shape of the pellet 5100 is not limited to a triangle or a hexagon, for example. For example, there are cases where the shape is made up of multiple triangles. In some cases, two squares (or polygons) may join together to form a quadrilateral (for example, a rhombus).

[0422] The thickness of the pellet 5100 is determined depending on the type of deposition gas, etc. The reason for this will be explained later. It is preferable that the thickness of the pellet 5100 is uniform. Thin pellets are preferable to thick cubes. The thickness of the PET 5100 is 0.4 nm or more and 1 nm or less, preferably 0.6 nm or more and 0.8 nm or less. For example, the pellet 5100 has a width of 1 nm or more and 3 nm or less, preferably The pellet 5100 is the one shown in FIG. ) corresponds to the initial nucleus described in (1). For example, the target 5 having In-Ga-Zn oxide When ions 5101 are bombarded onto the Ga-Zn-O layer 130, as shown in FIG. 45(B), A pellet 5100 having three layers, an In-O layer, and a Ga-Zn-O layer, is exfoliated. Figure 5(C) shows the structure of the exfoliated pellet 5100 observed from a direction parallel to the c-axis. The ret 5100 has two Ga-Zn-O layers (pan) and an In-O layer (filler). It can also be called a nano-sized sandwich structure.

[0423] As the pellet 5100 passes through the plasma, the sides may become negatively or positively charged. The pellet 5100 may have negatively charged oxygen atoms located on its sides, for example. The sides have charges of the same polarity, which causes repulsion between the charges, resulting in a flat or penetrating shape. It is possible to maintain the shape of the In-Ga-Z In the case of n-oxide, the oxygen atom bonded to the indium atom may be negatively charged. Or, an oxygen atom bonded to an indium atom, a gallium atom, or a zinc atom is negatively charged. In addition, when the pellet 5100 passes through the plasma, it may The area where it grows by bonding with indium atoms, gallium atoms, zinc atoms, oxygen atoms, etc. The difference in size between (2) and (1) in Figure 43 above is due to the growth in the plasma. Here, when the substrate 5120 is at room temperature, the pellets on the substrate 5120 The growth of 5100 is difficult to occur, resulting in nc-OS (see Figure 44(B)). Since the film can be formed at a low temperature, nc-OS can be formed even on a large substrate (5120). In order to grow the pellet 5100 in plasma, the sputtering method is used. Increasing the film formation power in the pellet 5 is effective. 100 structures can be stabilized.

[0424] As shown in FIG. 44(A) and FIG. 44(B), for example, the pellet 5100 is a plasma It flies like a kite through the air and flutters up to the top of the board 5120. Since the pellet 100 is electrically charged, it will be attracted to an area where other pellets 5100 are already deposited. Here, on the upper surface of the substrate 5120, a repulsive force is generated in a direction parallel to the upper surface of the substrate 5120. A horizontal magnetic field (also called a horizontal magnetic field) is generated between the substrate 5120 and the target 5120. Since a potential difference is applied between the substrate 5120 and the target 5130, Therefore, the pellet 5100 is disposed on the upper surface of the substrate 5120 in the following direction: The magnetic field and the electric current act on the object, creating a force (Lorentz force). This can be understood by the left-hand rule.

[0425] The pellet 5100 has a larger mass than an atom. In order to move the surface, it is important to apply some kind of force from the outside. One of these forces is It is possible that the force is generated by the action of a magnetic field and an electric current. To provide sufficient force to move the top surface of 5120, the top surface of substrate 5120 must: The magnetic field parallel to the upper surface of the substrate 5120 is 10 G or more, preferably 20 G or more, and more preferably It is preferable to provide a region where the resistance is 30 G or more, and more preferably 50 G or more. On the upper surface of the plate 5120, a magnetic field parallel to the upper surface of the substrate 5120 The magnetic field is 1.5 times or more, preferably 2 times or more, and more preferably 3 times or more than the magnetic field perpendicular to the upper surface. It is preferable to provide an area where the thickness is 5 times or more, more preferably 5 times or more.

[0426] At this time, the magnet and the substrate 5120 move or rotate relative to each other. The direction of the horizontal magnetic field on the upper surface of the substrate 5120 continues to change. On the upper surface of the plate 5120, the pellet 5100 is subjected to forces from various directions. You can move to.

[0427] Also, when the substrate 5120 is heated as shown in FIG. 44(A), the pellet 510 0 and the substrate 5120, the resistance due to friction etc. is small. The pellet 5100 glides over the top surface of the substrate 5120. The transfer occurs with the flat surface facing the substrate 5120. When the particles reach the side of the pellet 5100, the sides are joined together. The oxygen atom on the side of 00 is released. The released oxygen atom causes the Since oxygen vacancies may be filled, a CAAC-OS with a low density of defect states is obtained. The temperature of the upper surface of the plate 5120 is, for example, 100°C or higher and lower than 500°C, or 150°C or higher and 450°C. or 170° C. or higher and lower than 400° C. Even in such a case, it is possible to form a CAAC-OS film.

[0428] In addition, the pellet 5100 is heated on the substrate 5120, whereby the atoms are rearranged. The distortion of the structure caused by the collision of the ions 5101 is relaxed. 100 is almost a single crystal. Pellet 5100 is almost a single crystal. Even if the pellets 5100 are heated after being bonded together, the pellets 5100 themselves do not expand. Therefore, the gaps between the pellets 5100 widen, and the crystallization Defects such as grain boundaries do not form, and crevasses do not form.

[0429] In addition, the CAAC-OS is not made of a single-crystal oxide semiconductor. The aggregates of pellets 5100 (nanocrystals) resemble bricks or blocks stacked on top of each other. In addition, there are no grain boundaries between the pellets 5100. Heating during film formation, heating after film formation, or bending can cause deformation such as shrinkage in CAAC-OS. Even in such a case, it is possible to relieve local stress or release strain. This structure is suitable for use in flexible semiconductor devices. The resulting arrangement is like a disorderly stack of Red 5100 (nanocrystals).

[0430] When the target 5130 is sputtered by the ions 5101, not only the pellet 5100 but also Zinc oxide is lighter than pellet 5100. Therefore, it reaches the upper surface of the substrate 5120 first. A zinc oxide layer 5102 having a thickness of 2 nm or more and 5 nm or less, or 0.5 nm or more and 2 nm or less, is formed. Figure 46 shows a schematic cross-sectional view.

[0431] As shown in FIG. 46(A), a pellet 5105a and a pellet Here, the pellets 5105a and 5105b are deposited. The pellets 5105c are arranged so that their sides are in contact with each other. After being deposited on pellet 5105b, the pellet 510 slides on pellet 5105b. In another aspect of FIG. 5a, a plurality of particles 510 detached from the target along with zinc oxide. 3 is crystallized by heating from the substrate 5120 to form a region 5105a1. The number of particles 5103 may include oxygen, zinc, indium, and gallium, among others.

[0432] As shown in FIG. 46(B), the region 5105a1 is integral with the pellet 5105a. The pellet 5105c is formed by the side surface of the pellet 5105a. Place it so that it is in contact with another side of 5105b.

[0433] Next, as shown in FIG. 46(C), a pellet 5105d is further added to the pellet 5105a2. After being deposited on pellet 5105a2 and pellet 5105b, It slides on the other side of the pellet 5105c. The pellet 5105e slides on the zinc oxide layer 5102.

[0434] As shown in FIG. 46(D), the pellet 5105d has a side surface similar to that of the pellet 51. The pellet 5105e is placed so that its side faces the pellet 5105a2. Also, the other side of the pellet 5105d is placed in contact with the other side of the pellet 5105c. On the surface, a plurality of particles 5103 peeled off from the target 5130 together with zinc oxide are formed. Heat from plate 5120 causes crystallization, forming region 5105d1.

[0435] As described above, the piled pellets are arranged so that they come into contact with each other, and the side surfaces of the pellets are The growth occurs to form a CAAC-OS on the substrate 5120. The individual pellets of AC-OS are larger than those of nc-OS. The difference in size between (3) and (2) corresponds to the growth after deposition.

[0436] In addition, the gaps between the pellets become extremely small, forming one large pellet. One large pellet may have a single crystal structure. The size is 10 nm or more and 200 nm or less, 15 nm or more and 100 nm or less when viewed from the top surface, or In this case, the size of the transistors used can be between 20 nm and 50 nm. In an oxide semiconductor, a channel formation region may be contained in one large pellet. That is, a region having a single crystal structure can be used as a channel forming region. As the size of the lattice increases, the region with a single crystal structure becomes the channel formation region of the transistor. , may be used as source and drain regions.

[0437] In this way, the channel formation region of the transistor and the like are formed in a region having a single crystal structure. By doing so, it may be possible to improve the frequency characteristics of the transistor.

[0438] Based on the above model, it is assumed that the pellet 5100 is deposited on the substrate 5120. CAAC-OS can be deposited even when the surface does not have a crystalline structure. This indicates that the growth mechanism is different from epitaxial growth. AC-OS does not require laser crystallization and can be grown uniformly even on large glass substrates. For example, if the structure of the upper surface (surface to be formed) of the substrate 5120 is an amorphous structure (e.g., It is possible to form a CAAC-OS film even on amorphous silicon oxide.

[0439] In addition, even if the upper surface of the substrate 5120 on which the formation is performed is uneven, the CAAC-OS It can be seen that the pellets 5100 are arranged along the shape of the substrate 5120. If the surface is atomically flat, the pellet 5100 will have a flat surface that is parallel to the ab plane. If the thickness of the pellet 5100 is uniform, it is flat and has a uniform thickness. A layer with high crystallinity is formed. Then, the layer is stacked in n layers (n is a natural number). By doing so, CAAC-OS can be obtained.

[0440] On the other hand, even if the upper surface of the substrate 5120 has irregularities, the CAAC-OS can be easily formed by the pellet 51 The structure is made up of n layers (n is a natural number) of layers in which 00 are arranged along the unevenness. Because the surface of the CAAC-OS is uneven, gaps tend to form between the pellets. However, even in this case, intermolecular forces act between the pellets 5100, and unevenness may occur. Even if the pellets are uneven, they are arranged so that the gaps between them are as small as possible. Furthermore, a CAAC-OS having high crystallinity can be obtained.

[0441] Since the CAAC-OS film is formed using this model, the sputtered particles are distributed evenly across the film thickness. It is preferable that the sputtered particles are in the form of thick dices. In this case, the surface facing the substrate 5120 is not uniform, and the thickness and crystal orientation cannot be made uniform. There is.

[0442] The film formation model shown above allows for highly crystalline films to be formed even on a surface with an amorphous structure. Therefore, a CAAC-OS having the desired properties can be obtained.

[0443] A semiconductor device according to one embodiment of the present invention is formed using an oxide semiconductor film having any of the above structures. The device can be configured.

[0444] As described above, the structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiments. They can be used in combination.

[0445] (Embodiment 5) In this embodiment, a display function is realized by using the transistor described in the above embodiment. An example of a display device having such a configuration will be described below with reference to FIGS.

[0446] 27(A) is a top view showing an example of a display device. 0 is a pixel portion 702 provided on the first substrate 701 and a The source driver circuit section 704 and the gate driver circuit section 706, the pixel section 702, the source A seal disposed to surround the driver circuit section 704 and the gate driver circuit section 706 and a second substrate 705 provided so as to face the first substrate 701. The first substrate 701 and the second substrate 705 are sealed with a sealant 712. That is, the pixel section 702, the source driver circuit section 704, and the gate driver circuit The portion 706 is sealed by the first substrate 701, the sealant 712, and the second substrate 705. Although not shown in FIG. 27A, there is a gap between the first substrate 701 and the second substrate 705. A display element is provided.

[0447] The display device 700 is surrounded by a sealant 712 on the first substrate 701. The pixel section 702, the source driver circuit section 704, and the gate driver circuit section 706 are arranged in a region different from the region. The flexible printed circuit (FPC) terminal 708 is electrically connected to the flexible printed circuit (FPC) circuit 706. In addition, the FPC terminal section 708 is provided with an FP The pixel section 702 and the source driver circuit section 704 are connected by the FPC 716. Various signals are supplied to the pixel portion 702, the gate driver circuit portion 706, and the like. The base driver circuit section 704, the gate driver circuit section 706, and the FPC terminal section 708 are , and signal lines 710 are connected to the FPC 716. The pixel section 702, the source driver circuit section 704, the gate driver circuit section 706, and the like are connected via a line 710. 706 and an FPC terminal portion 708.

[0448] 27(B) is a top view showing an example of a display device. 27A. 00 is a display device in which the pixel section 80 is used instead of the pixel section 702 of the display device 700 shown in FIG. Use 2.

[0449] Furthermore, the display devices 700 and 800 may be provided with a plurality of gate driver circuit units 706. In addition, the display devices 700 and 800 include a source driver circuit section 704 and a gate driver circuit section 705. 7 shows an example in which the buffer circuit section 706 is formed on the same first substrate 701 as the pixel sections 702 and 802. However, the present invention is not limited to this configuration. For example, the gate driver circuit section 706 alone may be connected to the first The source driver circuit section 704 may be formed on the first substrate 701, or only the source driver circuit section 704 may be formed on the first substrate 701. In this case, a source driver circuit or a gate driver A substrate on which a circuit or the like is formed (for example, a driving circuit formed of a single crystal semiconductor film or a polycrystalline semiconductor film) The first substrate 701 may be mounted on the second substrate 702.

[0450] The method of connecting the separately formed drive circuit board is not particularly limited, and may be any of the following: (Chip On Glass) method, wire bonding method, etc. can be used. In this specification, the term "display device" refers to an image display device or a light source (illumination device). Also refers to connectors such as FPC and TCP (Tape Carrier) The module has a printed wiring board at the end of the TCP. The module or display element is connected to a drive circuit board or IC ( The display device also includes all modules on which a display device (integrated circuit) is directly mounted.

[0451] The display devices 700 and 800 include pixel sections 702 and 802, source driver circuit sections The gate driver circuit section 704 and the gate driver circuit section 706 have a plurality of transistors. A transistor which is one embodiment of the semiconductor device can be used.

[0452] The display device 700 is configured to use a liquid crystal element as a display element, and the display device 80 No. 0 is a configuration in which a light-emitting element is used as a display element.

[0453] Note that a display element, a display device which is a device having a display element, a light-emitting element, and a light-emitting element A light-emitting device, which is a device for emitting light, can take various forms or have various elements. The display element, display device, light-emitting element or light-emitting device is, for example, an EL (electroluminescent luminescence) elements (EL elements containing organic and inorganic materials, organic EL elements, inorganic EL elements), L ED (white LED, red LED, green LED, blue LED, etc.), transistor (current transistors that emit light in response to light), electron-emitting devices, liquid crystal devices, electronic ink, electrophoretic devices, Grating light valves (GLV), plasma displays (PDP), MEMS ( Display elements using microelectromechanical systems, digital micro Digital Micro Shutter (DMD), Digital Micro Shutter (DMS), MIRASOL (registered trademark), IMOD (Interference Modulation) element, shutter MEMS display element using the optical interference method, MEMS display element using the electrowetting method display elements using carbon nanotubes, piezoelectric ceramic displays, etc. In addition to these, there are also other types of contrast that can be achieved by electrical or magnetic effects. The display medium may have a variable luminance, reflectance, transmittance, etc. An example of a display device is an EL display. Examples of such displays include field emission displays (FEDs) and flat-panel SEDs. Display (SED: Surface-conduction Electron-e Examples of display devices using liquid crystal elements include LCDs. , LCD display (transmissive LCD, semi-transmissive LCD, reflective LCD LCD displays, direct-view LCD displays, and projection LCD displays. An example of a display device using ink or electrophoretic elements is electronic paper. In order to realize a semi-transmissive or reflective liquid crystal display, the pixel electrode A part or all of the pixel electrodes may be made to function as a reflective electrode. A part or all of the electrodes may be made of aluminum, silver, or the like. In this case, it is also possible to provide a memory circuit such as an SRAM below the reflective electrode. This further reduces power consumption.

[0454] First, the common parts of the display device 700 and the display device 800 will be explained, and then the differences will be explained. Regarding the display device 700 and the display device 800, the details thereof will be described with reference to FIGS. 28 and 29. I will explain.

[0455] <Explanation of common parts of display devices> FIG. 28 is a cross-sectional view corresponding to the cut surface taken along the dashed line QR shown in FIG. 27(A). FIG. 29 is a cross-sectional view corresponding to the cross section taken along the dashed line VW shown in FIG. 27(B). .

[0456] The display devices 700 and 800 shown in FIGS. 28 and 29 include a wiring section 711 and a pixel section 702 and 802 , a source driver circuit section 704 , and an FPC terminal section 708 . The lead wiring portion 711 includes a signal line 710 .

[0457] The signal line 710 of the wiring portion 711 is connected to the transistors 750 and 752. It is formed in the same process as the conductive film that functions as the gate electrode, source electrode, and drain electrode. The signal line 710 is connected to the gate electrodes, source electrodes, and drain electrodes of the transistors 750 and 752. A conductive film formed in a process different from that of the rain electrode, for example, a conductive film used as a lead wiring, It may be used.

[0458] The FPC terminal portion 708 includes a connection electrode 760, an anisotropic conductive film 780, and an FPC 71. The connection electrode 760 is connected to the source electrode layer and the drain electrode layer of the transistor 750. The connection electrode 760 is formed in the same process as the conductive film that functions as the electrode layer. The terminal of the electrode 716 is electrically connected to the electrode 716 via an anisotropic conductive film 780 .

[0459] In the display devices 700 and 800 shown in FIGS. 28 and 29, the pixel sections 702 and 8 02 includes a transistor 750, and the source driver circuit portion 704 includes a transistor 752. The transistor 750 and the transistor 752 are shown as examples. The transistor 750 and the transistor 150 shown in FIG. The configuration of the transistor 752 is not limited to the configuration of the transistor 150, and may be, for example, , transistors 151 to 154, transistors 190 to 194, transistor 150 A transistor 190A and a transistor 190B are used. That's fine.

[0460] The transistor used in this embodiment is made of a highly purified oxide in which the formation of oxygen vacancies is suppressed. The semiconductor film can reduce the current value in the off state (off current value). This allows the retention time of electrical signals such as image signals to be extended, and writing is possible when the power is on. The interval can also be set longer, so the frequency of refresh operations can be reduced. This has the effect of reducing power consumption.

[0461] In addition, the transistor used in this embodiment is highly purified and the formation of oxygen vacancies is suppressed. The oxide semiconductor film provides relatively high field-effect mobility, enabling high-speed operation. For example, by using such a transistor capable of high-speed driving in a liquid crystal display device, The switching transistor in the pixel section and the driver transistor used in the drive circuit section are the same. In other words, it can be formed on a single substrate, such as a silicon wafer, as a separate driving circuit. Therefore, it is not necessary to use a semiconductor device formed by a semiconductor device, and the number of parts of the semiconductor device can be reduced. In addition, by using a transistor that can be driven at high speed in the pixel portion, High quality images can be provided.

[0462] In addition, a signal connected to a transistor in a pixel portion and a transistor used in a driver circuit portion A wiring containing copper can be used as the wiring. The device has little signal delay caused by wiring resistance, making it possible to display on a large screen.

[0463] In this embodiment, the transistor 750 included in the pixel portion 702 and 802 The transistor 752 included in the source driver circuit section 704 has the same size. However, the present invention is not limited to this. The size (L / W) or the number of transistors used can be changed as needed. 28 and 29, the gate driver circuit section 706 can Although not shown, it can have the same configuration as the source driver circuit section 704 .

[0464] 28 and 29, the transistors 750 and 752 have A planarization insulating film 770 is provided on the insulating films 764 and 766 .

[0465] The insulating films 764 and 766 may be the insulating films 116 and 118 shown in the previous embodiment and the insulating films 116 and 118 shown in the previous embodiment. They can be formed using similar materials and manufacturing methods.

[0466] The planarization insulating film 770 may be made of polyimide resin, acrylic resin, or polyimide ammonia. Resin with heat resistance such as benzocyclobutene resin, polyamide resin, epoxy resin, etc. In addition, a plurality of insulating films made of these materials can be stacked. In this way, the planarization insulating film 770 may be formed. It may also be composed.

[0467] In addition, a conductive film serving as a source electrode and a drain electrode of the transistor 750 The conductive film 772 or the conductive film 844 is connected to one of the electrodes. A pixel electrode, which is formed on the planarization insulating film 770 and functions as one electrode of the display element, is formed on the planarization insulating film 770. The conductive film 772 is preferably a conductive film that transmits visible light. The conductive film may be made of a material selected from the group consisting of indium (In), zinc (Zn), and tin (Sn). In addition, the conductive film 844 may be a reflective conductive film. It is preferable to use

[0468] <Configuration Example 1 of a Display Device Using Liquid Crystal Elements as Display Elements> The display device 700 shown in FIG. 28 includes a liquid crystal element 775. The liquid crystal element 775 includes a conductive film The conductive film 774 is formed on the second substrate 705. The display device 700 shown in FIG. The alignment state of the liquid crystal layer 776 changes depending on the voltage applied to the conductive film 772 and the conductive film 774. This controls whether light is transmitted or not, allowing images to be displayed.

[0469] Although not shown in FIG. 28, the conductive films 772 and 774 are in contact with the liquid crystal layer 776. Although not shown in FIG. Color filters (colored films), black matrices (light-shielding films), polarizing components, phase difference components, reflection Optical members (optical substrates) such as a polarizing substrate and a positioning member may be provided as appropriate. Circularly polarized light produced by a retardation substrate may also be used. Either may be used.

[0470] The first substrate 701 and the second substrate 705 may be, for example, a glass substrate. In addition, flexible substrates are used as the first substrate 701 and the second substrate 705. The flexible substrate may be, for example, a plastic substrate.

[0471] In addition, a spacer 778 is provided between the first substrate 701 and the second substrate 705 . The spacers 778 are columnar spacers obtained by selectively etching the insulating film. The spacers are provided to control the film thickness (cell gap) of the liquid crystal layer 776. A spherical spacer may be used as 778.

[0472] When liquid crystal elements are used as display elements, thermotropic liquid crystals, low molecular weight liquid crystals, polymer liquid crystals, The liquid crystals that can be used include polymer dispersed liquid crystals, ferroelectric liquid crystals, and antiferroelectric liquid crystals. Depending on the conditions, the liquid crystal material can be in a cholesteric phase, a smectic phase, a cubic phase, or a chiral phase. It shows nematic phase, isotropic phase, etc.

[0473] In addition, when the in-plane switching method is adopted, a liquid crystal that exhibits a blue phase without using an alignment film may be used. The blue phase is one of the liquid crystal phases, and when the temperature of cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the black phase to the isotropic phase. Therefore, in order to improve the temperature range, a liquid crystal composition containing a chiral agent of several weight percent or more is used. The liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent is used in a liquid crystal layer. It has a short response time and is optically isotropic, so alignment treatment is not required. It also exhibits a blue phase. By using a liquid crystal composition containing a liquid crystal and a chiral agent, the viewing angle dependency can be reduced. Furthermore, when a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent is used, it is possible to form an alignment film. Since there is no need to polish the surface, rubbing is not required. This can prevent electrostatic breakdown caused by the electrostatic discharge, thereby reducing defects and damage to the liquid crystal display device during the manufacturing process. This can be done.

[0474] When a liquid crystal element is used as a display element, a TN (Twisted Nematic) ) mode, IPS (In-Plane-Switching) mode, FFS (Frin ge Field Switching) mode, ASM (Axially Symme tric aligned Micro-cell) mode, OCB(Optical Compensated Birefringence mode, FLC (Ferrero) lectric Liquid Crystal) mode, AFLC (AntiFerr It can be used in dielectric liquid crystal mode. .

[0475] In addition, normally black type liquid crystal display devices, for example, those employing vertical alignment (VA) mode The liquid crystal display device may be a transmission type. For example, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode , ASV mode, etc. can be used.

[0476] The display method in the pixel section 702 may be a progressive method, an interlace method, or the like. In addition, RG can be used as a color element controlled by pixels when displaying colors. For example, the R pixel and the G pixel are not limited to the three colors R, G, and B (R represents red, G represents green, and B represents blue). It may be composed of four pixels: a blue pixel, a blue pixel, and a white pixel. As shown above, two colors of RGB compose one color element, and two different colors are created by the color element. Alternatively, you can add one or more colors such as yellow, cyan, magenta, etc. to RGB. The size of the display area may be different for each dot of the color element. However, the disclosed invention is not limited to color display devices, but also includes monochrome display devices. The present invention can also be applied to display devices such as:

[0477] <Display device using light-emitting elements as display elements> The display device 800 shown in FIG. 29 includes a light-emitting element 880. The light-emitting element 880 includes a conductive film The display device 800 includes a light-emitting element 880. The EL layer 846 of the display panel emits light, thereby displaying an image.

[0478] 29. In addition, the display device 800 shown in FIG. 29 includes a planarization insulating film 770 and a conductive film 844. An insulating film 830 is provided. The insulating film 830 covers part of the conductive film 844. The element 880 has a top-emission structure. Therefore, the conductive film 848 has a light-transmitting property. It transmits light emitted by the EL layer 846. In this embodiment, For example, a light emitting structure for emitting light to the conductive film 844 side is shown, but the present invention is not limited to this. a bottom emission structure in which light is emitted to both the conductive film 844 and the conductive film 848; It can also be applied to dual emission structures.

[0479] A colored film 836 is provided at a position overlapping the light emitting element 880, and a colored film 836 is provided at a position overlapping the insulating film 830. A light-shielding film 838 is provided in the position where the light-shielding film 838 is to be drawn, the wiring portion 711, and the source driver circuit portion 704. The colored film 836 and the light-shielding film 838 are covered with an insulating film 834. Light-emitting element The space between the insulating film 834 and the insulating film 834 is filled with a sealing film 832. Although the configuration in which the colored film 836 is provided has been exemplified, the present invention is not limited to this. For example, When the EL layer 846 is formed by coloring, the colored film 836 is not provided. You may do so.

[0480] Next, a display device 700A, which is a modification of the display device 700 shown in FIG. 28, will be described with reference to FIG. This will be explained using:

[0481] <Configuration Example 2 of a Display Device Using Liquid Crystal Elements as Display Elements> The display device 700A shown in FIG. 30 includes a liquid crystal element 775. The liquid crystal element 775 is a conductive The conductive film 773 is formed on the first substrate 70. 30. The planarization insulating film 770 on the substrate 1 functions as a reflective electrode. The display device 700A utilizes external light, reflects the light on the conductive film 773, and displays the light through the colored film 836. This is a so-called reflective color liquid crystal display device.

[0482] In the display device 700A shown in FIG. 30, the planarization insulating film 770 of the pixel section 702 The unevenness is formed by, for example, forming the planarization insulating film 770 with an organic resin film or the like. The reflecting layer can be formed by forming a surface of the organic resin film with irregularities. The conductive film 773 functioning as an electrode is formed along the unevenness. When light is incident on the conductive film 773, it can be diffused and reflected by the surface of the conductive film 773. This makes it possible to improve visibility.

[0483] The display device 700A also includes a light-shielding film 838, an insulating film 834, and a The light-shielding film 838, the insulating film 834, and the coloring film 836 are included in the display device 8. 00. Also, the display device 70 The conductive film 773 included in the transistor 750 functions as a source electrode or a drain electrode of the transistor 750. The conductive film 773 is electrically connected to a conductive film having the same function as the conductive film 844. and methods can be used to form the same.

[0484] The display device 700A also includes a capacitor 790. The capacitor 790 has a pair of electrodes More specifically, the capacitor 790 is connected to the gate of the transistor 750. A conductive film formed in the same process as a conductive film that functions as an electrode, a source electrode, and a drain electrode as one electrode, and a conductive film which functions as a lead wiring of the transistor 750. A conductive film 792 formed in one step is used as the other electrode, and an insulating film is formed between the conductive films. It has 764.

[0485] 28, the display device 700A has a wiring section 7 11 has a signal line 710a instead of the signal line 710. Also, the display device 700A has Unlike the display device 700 shown in FIG. 28, the FPC terminal portion 708 has a contact hole 760 instead of the connection electrode 760. Instead, the signal line 710a has a connection electrode 760a. For example, the signal line 710a, the connection electrode 760a, and the conductive film 2 are formed in the same process. 792 can be formed in the same process by processing one conductive film.

[0486] A transistor that is a semiconductor device of one embodiment of the present invention includes a conductive film that functions as a gate electrode. and a conductive film functioning as a source electrode and a drain electrode are formed in the same process. That is, a conductive film functioning as a gate electrode and a conductive film functioning as a source electrode and a drain electrode are formed. Therefore, the conductive film that functions as the gate electrode, Alternatively, either or both of the conductive films functioning as a source electrode and a drain electrode may be formed of different materials. In some cases, the wiring is routed via a conductive film.

[0487] Here, a conductive film functioning as a gate electrode and a conductive film functioning as a source electrode and a drain electrode are formed. An example of a connecting portion for connecting the conductive films will be described with reference to FIG.

[0488] FIG. 37(A) is a top view of the connection part 900, and FIG. 37(B) is a view of a point on FIG. 37(A). 37B is a cross-sectional view taken along the dashed line Z1-Z2. For clarity, insulating films and the like are not shown in FIG. Some of the components are omitted.

[0489] The connection portion 900 includes an insulating film 904 on a substrate 902, an insulating film 908 on the insulating film 904, and Conductive films 910, 912, and 914 on the insulating film 908, and 12, 914 and an insulating film 916, and openings 930a and 930b provided in the insulating film 916. A conductive film 945 connected to the conductive film 910 and the conductive film 912 via an insulating film 916 and and an insulating film 918 over the conductive film 945 .

[0490] The substrate 902 can be made of a material similar to that of the substrate 102 described in Embodiment 1. The insulating films 904, 908, and 916 are the same as the insulating film 104 shown in Embodiment 1. , 108, and 116 can be used. The conductive films 14 and 945 may be made of the same materials as the conductive films 110, 112, and 114 described in Embodiment 1. can be used.

[0491] The conductive film 910 may be a film connected to a source electrode or a drain electrode of a transistor. The conductive film 912 is a film that is connected to a source electrode or a drain electrode of a transistor. The conductive film 945 is connected to the conductive film 910 through the openings 930a and 930b. The conductive film 912 is electrically connected.

[0492] Next, a conductive film functioning as a gate electrode and a conductive film functioning as a source electrode and a drain electrode are formed. Another example of a connecting portion for connecting conductive films will be described with reference to FIG.

[0493] FIG. 40(A) is a top view of the connection part 900, and FIG. 40(B) is a view of a point on FIG. 40(A). 40(B) is a cross-sectional view taken along the dashed line Z1-Z2. For clarity, insulating films and the like are not shown in FIG. Some of the components are omitted.

[0494] The conductive film 910 and the conductive film 912 are connected via the conductive film 120a. The conductive film 120a is a conductive film that is formed and etched simultaneously with the conductive film 120. Therefore, they have the same material.

[0495] As described above, the transistor which is a semiconductor device of one embodiment of the present invention can be used in various display devices. It is possible to apply

[0496] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0497] (Embodiment 6) In this embodiment, a display device in which a semiconductor device of one embodiment of the present invention can be used will be described. This will be explained with reference to FIG.

[0498] The display device shown in FIG. 31(A) has a region having pixels of a display element (hereinafter referred to as a pixel portion 502). ) and a circuit section ( hereinafter referred to as a drive circuit section 504), and a circuit having a function of protecting the element (hereinafter referred to as a protection circuit 50 6) and a terminal portion 507. Note that the protection circuit 506 is not provided. That's fine.

[0499] A part or the whole of the driver circuit portion 504 is formed on the same substrate as the pixel portion 502. This makes it possible to reduce the number of parts and terminals. When a part or all of the pixel portion 502 is not formed on the same substrate, the driving circuit A part or the whole of the path portion 504 is COG or TAB (Tape Automated Bearing). It can be implemented by

[0500] The pixel section 502 is arranged in X rows (X is a natural number of 2 or more) and Y columns (Y is a natural number of 2 or more). The display device has a circuit for driving a plurality of display elements (hereinafter referred to as pixel circuit 501), The path section 504 is a circuit (hereinafter referred to as a gate driver) that outputs a signal (scanning signal) for selecting a pixel. 504a), for supplying signals (data signals) for driving the display elements of the pixels. The source driver 504b includes a driving circuit such as the circuit (hereinafter referred to as a source driver 504b).

[0501] The gate driver 504a includes a shift register and the like. A signal for driving the shift register is inputted through the terminal section 507, and a signal for outputting the shift register is outputted. For example, the gate driver 504a receives a start pulse signal, a clock signal, etc. The gate driver 504a receives a scanning signal and outputs a pulse signal. The gate has a function of controlling the potential of the scanning lines GL_1 to GL_X. A plurality of drivers 504a are provided, and the plurality of gate drivers 504a drive the scanning lines GL_1 to Alternatively, the gate driver 504a may control the GL_X by dividing it into the initialization signal However, the gate driver 50 has a function of supplying 4a may also provide other signals.

[0502] The source driver 504b includes a shift register and the like. Through the terminal section 507, signals for driving the shift register as well as the source of the data signal are transmitted. The source driver 504b receives a signal (image signal) that is to be output from the pixel circuit The source driver 504b has a function of generating a data signal to be written to the source driver 501. A data signal is generated in accordance with a pulse signal obtained by inputting a start pulse, a clock signal, etc. The source driver 504b has a function of controlling the output of a data signal. The signal lines DL_1 to DL_Y are connected to the power supply 101. Alternatively, the source driver 504b may have a function to supply an initialization signal. However, the present invention is not limited to this, and the source driver 504b may supply other signals. It is Noh.

[0503] The source driver 504b is configured using, for example, a plurality of analog switches. The source driver 504b sequentially turns on a plurality of analog switches, The image signal can be time-divided and output as a data signal. The source driver 504b may be configured using the same.

[0504] Each of the plurality of pixel circuits 501 is connected to one of the plurality of scanning lines GL to which a scanning signal is applied. A pulse signal is input via the signal line DL, and a data signal is given via one of the signal lines DL. A data signal is input to each of the pixel circuits 501. For example, the pixel in the mth row and nth column The circuit 501 outputs a signal to a gate driver 504a via a scanning line GL_m (m is a natural number equal to or less than X). A pulse signal is input from the signal line DL_n (n is Y or less) according to the potential of the scanning line GL_m. A data signal is input from the source driver 504b via the line 504c (a natural number).

[0505] The protection circuit 506 shown in FIG. 31(A) is, for example, a gate driver 504a and a pixel circuit 5 01. Alternatively, the protection circuit 506 is connected to the scanning line GL, which is the wiring between the source driver The signal line DL is connected between the driver 504b and the pixel circuit 501. The circuit 506 can be connected to a wiring between the gate driver 504a and the terminal section 507. Alternatively, the protection circuit 506 may be provided on the wiring between the source driver 504b and the terminal section 507. The terminal section 507 can be connected to the display device via an external circuit. This refers to the part where terminals for inputting control signals and image signals are provided.

[0506] When a potential outside a certain range is applied to the wiring to which the protection circuit 506 is connected, the protection circuit 506 This is a circuit that brings one wire into electrical continuity with another wire.

[0507] As shown in FIG. 31(A), a pixel section 502 and a driver circuit section 504 are provided with a protection circuit 50. 6, ESD (Electro Static Discharge: This can improve the resistance of the display device to overcurrents caused by electrostatic discharges and the like. However, the configuration of the protection circuit 506 is not limited to this. For example, A configuration in which a protection circuit 506 is connected, or a configuration in which the protection circuit 506 is connected to the source driver 504b Alternatively, a configuration in which a protection circuit 506 is connected to the terminal portion 507 may be used. It can also be done as follows.

[0508] In FIG. 31(A), the gate driver 504a and the source driver 504b Therefore, although an example in which the driver circuit portion 504 is formed is shown, the present invention is not limited to this configuration. For example, only the gate driver 504a is formed, and a separately prepared source driver circuit is formed. A substrate (for example, a drive circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is implemented. It may also be configured to be equipped with

[0509] Furthermore, the plurality of pixel circuits 501 shown in FIG. 31(A) may be, for example, a configuration shown in FIG. 31(B). It can be said that:

[0510] The pixel circuit 501 shown in FIG. 31B includes a liquid crystal element 570, a transistor 550, and a capacitor. and a capacitance element 560.

[0511] The semiconductor device of one embodiment of the present invention can be used as the transistor 550, for example. The transistor 550 can be any of the transistors 150 to 155 shown in the above embodiments. 4, transistors 190 to 194, transistor 150A, transistor 190A, and and transistor 190B, etc. can be applied.

[0512] The potential of one of the pair of electrodes of the liquid crystal element 570 is set appropriately according to the specifications of the pixel circuit 501. The orientation state of the liquid crystal element 570 is set by the written data. A common potential is applied to one of a pair of electrodes of the liquid crystal element 570 included in each of the pixel circuits 501. A common potential may be applied to the pair of liquid crystal elements 570 of the pixel circuits 501 in each row. One of the electrodes may be given a different potential.

[0513] For example, the display device including the liquid crystal element 570 can be driven in a TN mode, an STN mode, or the like. Mode, VA mode, ASM (Axially Symmetric Aligned Mode) Micro-cell mode, OCB (Optically Compensated Birefringence mode, FLC (Ferroelectric Liquid Crystal id Crystal) mode, AFLC (AntiFerroelectric Li Quid Crystal) mode, MVA mode, PVA (Patterned Ve Vertical Alignment mode, IPS mode, FFS mode, or TBA (Transverse Bend Alignment) mode may also be used. In addition to the above-mentioned driving method, the display device can also be driven by an ECB (Electric Carrier Board) or the like. Ally Controlled Birefringence mode, PDLC (P Polymer Dispersed Liquid Crystal (PNLC) mode (Polymer Network Liquid Crystal) mode, guest However, there are various types of liquid crystal elements and their driving methods, and they are not limited to these. A variety of materials can be used.

[0514] In the pixel circuit 501 in the mth row and the nth column, the source electrode or the drain electrode of the transistor 550 One of the electrodes is electrically connected to the signal line DL_n, and the other is a pair of electrodes of the liquid crystal element 570. The gate electrode of the transistor 550 is electrically connected to the other of the scan lines GL _m. The transistor 550 can be turned on or off. This has the function of controlling the writing of data of the data signal.

[0515] One of the pair of electrodes of the capacitor 560 is connected to a wiring to which a potential is supplied (hereinafter, a potential supply line VL ) and the other is electrically connected to the other of the pair of electrodes of the liquid crystal element 570. The value of the potential of the potential supply line VL is set appropriately according to the specifications of the pixel circuit 501. The capacitor 560 functions as a storage capacitor for storing written data.

[0516] For example, in a display device having the pixel circuit 501 of FIG. 31(B), The pixel circuits 501 in each row are sequentially selected by the gate driver 504a shown in FIG. 550 is turned on and data of the data signal is written.

[0517] The pixel circuit 501 in which data has been written is turned off by turning off the transistor 550. By repeating this process for each row, an image can be displayed.

[0518] Furthermore, the plurality of pixel circuits 501 shown in FIG. 31(A) may be, for example, a configuration shown in FIG. 31(C). It can be said that:

[0519] The pixel circuit 501 shown in FIG. 31C includes transistors 552 and 554 and a capacitor. The transistor 552 and the light-emitting element 572 are connected to each other. One or both of the transistors 150 to 155 shown in the previous embodiment may be used as the transistors 554. 4, transistors 190 to 194, transistor 150A, transistor 190A, and and transistor 190B, etc. can be applied.

[0520] One of the source and drain electrodes of the transistor 552 is supplied with a data signal. The gate voltage of the transistor 552 is electrically connected to the wiring (signal line DL_n). The electrodes are electrically connected to wiring (scanning lines GL_m) to which gate signals are applied.

[0521] Transistor 552 is turned on or off to transfer the data of the data signal. It has the function of controlling the writing of data.

[0522] One of the pair of electrodes of the capacitor 562 is connected to a wiring to which a potential is applied (hereinafter, a potential supply line VL _a), and the other is electrically connected to the source electrode and drain electrode of the transistor 552. The second electrode is electrically connected to the other of the first and second electrodes.

[0523] The capacitor 562 functions as a storage capacitor for holding written data.

[0524] One of the source electrode and the drain electrode of the transistor 554 is connected to the potential supply line VL_a. Furthermore, the gate electrode of transistor 554 is electrically connected to the It is electrically connected to the other of the source electrode and the drain electrode.

[0525] One of the anode and cathode of the light emitting element 572 is electrically connected to the potential supply line VL_b. The other is electrically connected to the other of the source electrode and drain electrode of the transistor 554. will be done.

[0526] The light emitting element 572 may be, for example, an organic electroluminescence element (also known as an organic EL element). However, the light emitting element 572 is not limited to this. Alternatively, an inorganic EL element made of an inorganic material may be used.

[0527] A high power supply potential VDD is applied to one of the potential supply lines VL_a and VL_b. and the other is supplied with a low power supply potential VSS.

[0528] In a display device having the pixel circuit 501 of FIG. 31(C), for example, The pixel circuits 501 in each row are sequentially selected by the gate driver 504a, and the transistors 552 are turned on. The data signal is written by turning it on.

[0529] The pixel circuit 501 to which the data has been written is turned off by turning off the transistor 552. Furthermore, the transistor 554 is held in a holding state in response to the potential of the written data signal. The amount of current flowing between the source electrode and the drain electrode is controlled, and the light emitting element 572 The light is emitted at a brightness that corresponds to the flow rate. By repeating this process row by row, an image can be displayed.

[0530] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done.

[0531] (Embodiment 7) In this embodiment, a display module in which the semiconductor device of one embodiment of the present invention can be used is described. The electronic device will be described with reference to FIGS. 32 and 33.

[0532] The display module 8000 shown in FIG. 32 includes an upper cover 8001 and a lower cover 8002. Between them, touch panel 8004 connected to FPC8003 and Display panel 8006, backlight 8007, frame 8009, printed circuit board 801 0, has battery 8011.

[0533] The semiconductor device of one embodiment of the present invention can be used for the display panel 8006, for example.

[0534] The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel The shape and dimensions can be changed as needed to fit the size of the 8006.

[0535] The touch panel 8004 is a resistive or capacitive touch panel. The display panel 8006 can be used by overlapping it with the opposing substrate (sealing substrate). It is also possible to provide the display panel 8 with a touch panel function. It is also possible to provide an optical sensor in each pixel of 006 to make it an optical touch panel.

[0536] The backlight 8007 has a light source 8008. In FIG. Although the configuration in which the light source 8008 is disposed on the base 8007 has been illustrated, the present invention is not limited to this. For example, a light source 8008 is arranged at the end of a backlight 8007, and a light diffusion plate is further used. In addition, when a self-luminous light emitting element such as an organic EL element is used, or when a reflective In the case of a flat panel or the like, the backlight 8007 may not be provided.

[0537] The frame 8009 has a function of protecting the display panel 8006 and also a function of preventing the movement of the printed circuit board 8010. It also functions as an electromagnetic shield to block electromagnetic waves generated by the operation of the The frame 8009 may also function as a heat sink.

[0538] The printed circuit board 8010 includes a power supply circuit, a signal circuit for outputting a video signal and a clock signal. The power supply circuit is provided with a signal processing circuit. Alternatively, the power source may be a battery 8011 provided separately. 1 can be omitted if commercial power is used.

[0539] In addition, the display module 8000 includes components such as a polarizing plate, a retardation plate, and a prism sheet. It may also be provided in addition.

[0540] 33(A) to 33(H) are diagrams showing electronic devices. These electronic devices are Body 5000, display unit 5001, speaker 5003, LED lamp 5004, operation key 50 05 (including a power switch or an operation switch), a connection terminal 5006, a sensor 5007 ( Force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances , sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, 5008, a microphone 5009, etc. can.

[0541] FIG. 33(A) shows a mobile computer, which includes, in addition to the above, a switch 5009 , an infrared port 5010, etc. FIG. 33(B) shows a portable terminal equipped with a recording medium. A portable image reproducing device (for example, a DVD reproducing device) is also included. It can have a display unit 5002, a recording medium reading unit 5011, etc. It is a group-type display, and in addition to the above, it has a second display unit 5002, a support unit 5012 , earphones 5013, etc. FIG. 33(D) shows a portable gaming machine. In addition to the above, it may have a recording medium reading unit 5011, etc. It is a digital camera with a TV receiving function, and in addition to the above, it also has an antenna 5014, The mobile phone may have a shutter button 5015, an image receiving unit 5016, etc. It is a belt-type gaming machine, and in addition to the above, it has a second display unit 5002, a recording medium reading unit 5011, , etc. FIG. 33(G) shows a television receiver, which, in addition to the above, has It can have a tuner, an image processor, etc. FIG. 33(H) shows a portable television receiver. In addition to the above, it has a charger 5017 capable of transmitting and receiving signals, etc. can be done.

[0542] The electronic devices shown in FIGS. 33A to 33H can have various functions. For example, functions to display various information (still images, videos, text images, etc.) on the display, Panel function, calendar, date or time display function, various software ( It has a function to control processing by a program, a wireless communication function, and various controls using the wireless communication function. Functions for connecting to computer networks, transmitting various data using wireless communication functions, The function of receiving, reading out the program or data recorded on the recording medium and displaying it on the display Furthermore, in an electronic device having multiple display units, In this case, one display section is used mainly to display image information, and another display section is used mainly to display text information. or a function to display images that take parallax into account on multiple displays to create a three-dimensional effect. Furthermore, in electronic devices having an image receiving unit, The camera has the functions to take still images, record videos, and automatically or manually correct captured images. function to correct the image, to save the captured image to a recording medium (external or built-in to the camera), 33(A) to 33(B) can have a function of displaying the image on the display unit. The functions that the electronic device shown in 3(H) can have are not limited to these, and various functions can be It can have.

[0543] The electronic device described in this embodiment has a display unit for displaying some information. Note that the semiconductor device of one embodiment of the present invention is not limited to an electronic device that does not have a display portion. It can also be applied to

[0544] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. can be done. [Explanation of symbols]

[0545] 102 Circuit Board 103 insulating film 104 insulating film 104a Nitride insulating film 104b Oxide insulating film 106 Oxide semiconductor film 106a area 106b area 106c area 106d area 107a Oxide semiconductor film 107b Oxide semiconductor film 107c Oxide semiconductor film 108 insulating film 109 Conductive film 110 Conductive film 110a Conductive film 110b Conductive film 110c conductive film 111 Mask 112 Conductive film 112a Conductive film 112b Conductive film 112c conductive film 114 Conductive film 114a Conductive film 114b Conductive film 114c conductive film 116 Insulating film 117 Impurity elements 118 insulating film 119 Membrane 120 Conductive film 120a Conductive film 121 Oxygen 122 insulating film 123 Etching gas 124 Conductive Film 135 End 136 End 137 End 140a opening 140b opening 142a opening 142b opening 150 transistors 150A transistor 151 transistors 152 transistors 153 Transistor 154 transistors 156 Oxide semiconductor film 159 Capacitive element 162 PCB 164 insulating film 164a Nitride insulating film 164b Oxide insulating film 166 Oxide semiconductor film 166a area 166b area 166c area 166d area 166x area 166y area 167 Etching gas 167a Oxide semiconductor film 167b Oxide semiconductor film 167c Oxide semiconductor film 168 insulating film 169 Conductive Film 170 Conductive film 170a Conductive film 170b Conductive film 170c conductive film 170d conductive film 170e Conductive film 172 Conductive film 172a Conductive film 172b Conductive film 172c conductive film 172d Conductive film 172e Conductive film 174 Conductive Film 174a Conductive film 174b Conductive film 174c conductive film 174d Conductive film 174e Conductive film 176 insulating film 177 Impurity elements 178 insulating film 180a opening 180b opening 181 Conductive film 182 insulating film 182a opening 182b opening 183 Opening 184 Conductive Film 190 transistors 190A transistor 190B transistor 191 transistors 192 transistors 193 transistors 194 transistors 195 End 196 End 197 End 198 Oxide semiconductor film 199 Capacitive element 501 pixel circuit 502 pixel section 504 Drive circuit section 504a Gate Driver 504b source driver 506 Protection circuit 507 Terminal section 550 transistors 552 transistor 554 Transistor 560 Capacitor 562 Capacitor 570 Liquid Crystal Devices 572 Light-emitting element 700 Display device 700A display device 701 PCB 702 pixel section 704 Source driver circuit section 705 PCB 706 Gate driver circuit section 708 FPC terminal section 710 Signal Line 710a signal line 711 Wiring section 712 Sealing material 716 FPC 750 transistors 752 transistors 760 connecting electrode 760a Connecting electrode 764 insulating film 766 Insulating Film 770 Planarization insulating film 772 Conductive film 773 Conductive Film 774 Conductive film 775 Liquid Crystal Elements 776 Liquid Crystal Layer 777 Conductive Film 778 Spacer 780 Anisotropic Conductive Film 790 Capacitor 792 Conductive film 800 display device 802 pixel section 830 insulating film 832 Sealing film 834 insulating film 836 Colored film 838 Light-shielding film 844 Conductive film 846 EL layer 848 Conductive film 880 Light-emitting element 900 Connection 902 PCB 904 Insulating film 908 Insulating film 910 Conductive film 912 Conductive film 914 Conductive film 916 Insulating film 918 Insulating film 930a opening 930b opening 945 Conductive film 5000 cabinets 5001 Display section 5002 Display section 5003 Speaker 5004 LED lamp 5005 Operation key 5006 Connection terminal 5007 Sensor 5008 Microphone 5009 Switch 5010 Infrared port 5011 Recording medium reading unit 5012 Support part 5013 Earphones 5014 Antenna 5015 Shutter button 5016 Image receiving unit 5017 charger 5100 pellets 5100a pellets 5100b pellets 5101 AEON 5102 Zinc oxide layer 5103 particles 5105a Pellets 5105a1 area 5105a2 pellets 5105b Pellets 5105c Pellets 5105d Pellets 5105d1 area 5105e Pellets 5120 board 5130 Target 5161 area 8000 Display Module 8001 Top cover 8002 Lower cover 8003 FPC 8004 Touch Panel 8005 FPC 8006 Display Panel 8007 Backlight 8008 light source 8009 Frame 8010 Printed Circuit Board 8011 Battery

Claims

1. A display device having a plurality of pixels each having a transistor, a first conductive film having a region in contact with an upper surface of the substrate and functioning as a first gate electrode of the transistor; a first insulating film having a region located above the first conductive film; an oxide semiconductor film having a region in contact with a top surface of the first insulating film and including a channel formation region of the transistor; a second conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as one of a source electrode and a drain electrode of the transistor; a third conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as the other of the source electrode and the drain electrode of the transistor; a second insulating film having a region in contact with an upper surface of the oxide semiconductor film; a fourth conductive film having a region overlapping with the oxide semiconductor film with the second insulating film interposed therebetween and functioning as a second gate electrode of the transistor; and a third insulating film having a region in contact with an upper surface of the second conductive film, a region in contact with an upper surface of the third conductive film, a region in contact with an upper surface of the fourth conductive film, and a region in contact with an upper surface of the oxide semiconductor film; a fifth conductive film having a region in contact with the upper surface of the substrate and made of the same material as the first conductive film; a sixth conductive film having a region in contact with an upper surface of the fifth conductive film and a region in contact with a lower surface of the third insulating film; the third conductive film is electrically connected to the sixth conductive film via the fifth conductive film; The second conductive film, the third conductive film, the fourth conductive film, and the sixth conductive film are made of the same material.

2. A display device having a plurality of pixels each having a transistor, a first conductive film having a region in contact with an upper surface of the substrate and functioning as a first gate electrode of the transistor; a first insulating film having a region located above the first conductive film; an oxide semiconductor film having a region in contact with a top surface of the first insulating film and including a channel formation region of the transistor; a second conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as one of a source electrode and a drain electrode of the transistor; a third conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as the other of the source electrode and the drain electrode of the transistor; a second insulating film having a region in contact with an upper surface of the oxide semiconductor film; a fourth conductive film having a region overlapping with the oxide semiconductor film with the second insulating film interposed therebetween and functioning as a second gate electrode of the transistor; and a third insulating film having a region in contact with an upper surface of the second conductive film, a region in contact with an upper surface of the third conductive film, a region in contact with an upper surface of the fourth conductive film, and a region in contact with an upper surface of the oxide semiconductor film; a fifth conductive film having a region in contact with the upper surface of the substrate and made of the same material as the first conductive film; a sixth conductive film having a region in contact with an upper surface of the fifth conductive film and a region in contact with a lower surface of the third insulating film; the third conductive film is electrically connected to the sixth conductive film via the fifth conductive film; the second conductive film, the third conductive film, the fourth conductive film, and the sixth conductive film have the same material; the first insulating film has a laminated structure of a first film containing nitrogen and silicon and a second film located on the first film and containing oxygen and silicon; the second insulating film contains oxygen and silicon, The display device, wherein the third insulating film contains oxygen and silicon.

3. In claim 1 or 2, the second insulating film and the third insulating film each have a single-layer structure or a multilayer structure, The display device, wherein the second conductive film and the third conductive film have a single-layer structure or a stacked-layer structure.

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