Display device

Abstract

To provide a novel semiconductor device using an oxide semiconductor, in particular, to provide a planar type semiconductor device using an oxide semiconductor, or to provide a semiconductor device using an oxide semiconductor and that has a large on-state current.SOLUTION: A display device comprises: an oxide insulating film; an oxide semiconductor film on the oxide insulating film; a source electrode and a drain electrode contacted with the oxide semiconductor film; a gate insulating film between the source electrode and the drain electrode; and a gate electrode overlapped with the oxide semiconductor film via the gate insulating film. The oxide semiconductor film has: a first region overlapped with the gate electrode; and a second region not overlapped with the gate electrode, nor the source electrode, nor the drain electrode. Impurity element concentrations of the first region and the second region are different from each other. The gate electrode, the source electrode, and the drain electrode contain the same metal element.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

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

[0003] In this specification and the like, a semiconductor device is a device that can function by utilizing semiconductor characteristics. Refers to devices in general. Semiconductor elements such as transistors, semiconductor circuits, computing devices, 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] JP 2006-165529 A 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 effective than a planar type transistor. 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 the device (for example, 4k x 2k (horizontal pixel count = 3840 pixels, vertical pixel count = 3840 pixels) Prime number = 2048 pixels) or 8k x 4k (horizontal pixels = 7680 pixels, vertical pixels As the development of high-resolution display devices (represented by displays with 4320 pixels) progresses, the use of 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. There is a problem in that signal delays and the like increase depending on the capacitance, deteriorating the image quality of the display device. In addition, in the case of an inverted staggered transistor, the transistor Therefore, a transistor using an oxide semiconductor film is used. The structure of the Renner-type transistor 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 and having a large on-state current, or to provide an off-state current using an oxide semiconductor To provide a semiconductor device with a small current, or to provide a semiconductor device with a small occupancy area using an oxide semiconductor To provide a semiconductor device using an oxide semiconductor and having stable electrical characteristics. 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 to provide 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 may be solved by the specification. The above problems are obvious from the description of the specification, etc., and 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 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. A source electrode and a drain electrode in contact with the body membrane, and a gate insulator between the source electrode and the drain electrode. 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, and a second region overlapping the gate electrode, the source electrode, and the 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 of Unlike the above, the gate electrode, the source electrode, and the drain electrode each 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, and A source electrode and a drain electrode in contact with the oxide semiconductor film, and a layer 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 includes a first region overlapping with the gate electrode, a second region overlapping with the gate electrode, a source electrode, and a drain 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 concentration of silicon is different, and a nitride insulating film is provided in contact with the second region. The semiconductor device is 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 second region has a higher impurity element concentration than 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 is 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, and A source electrode and a drain electrode in contact with the oxide semiconductor film, and a layer 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 includes a first region overlapping with the gate electrode, a second region overlapping with the gate electrode, a source electrode, and a drain electrode. and a second region that does not overlap with the rain 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, and A source electrode and a drain electrode in contact with the oxide semiconductor film, and a layer 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 includes a first region overlapping with the gate electrode, a second region overlapping with the gate electrode, a source electrode, and a drain 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 each contain the same metal element. This is a semiconductor device having the following characteristics.

[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, It is preferable that the metal oxide is selected from the group consisting of Al, Ti, Ga, Y, Zr, La, Ce, Nd, and Hf. In each of the above structures, the oxide semiconductor film includes a crystal part, and the c-axis of the crystal part is an oxide It is preferable that the direction be parallel to the normal vector of the surface on which the semiconductor film is formed.

[0018] Another embodiment of the present invention is a semiconductor device using any one of the above structures. It is a display device. Effect 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 which uses an oxide semiconductor and has a large on-state current can be provided. A semiconductor device including an oxide semiconductor and having a low off-state current can be provided. It is possible to provide a semiconductor device which uses an oxide semiconductor and occupies a small area. It is possible to provide a semiconductor device using an oxide semiconductor and having stable electrical characteristics. In addition, 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 become apparent from the description in the specification, drawings, claims, etc. It is possible to extract other effects from the descriptions in the claims, etc. [Brief description 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. [Diagram 2] FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Diagram 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. [Diagram 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 embodiment 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. [Diagram 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 showing one embodiment of a display device. [Figure 29] FIG. 1 is a cross-sectional view showing one embodiment of a display device. [Diagram 30] FIG. 1 is a cross-sectional view showing one embodiment of a display device. [Diagram 31] 1A and 1B are a block diagram and a circuit diagram illustrating a display device. [Diagram 32] FIG. 2 is a diagram illustrating a display module. [Diagram 33] 1A to 1C are diagrams illustrating electronic devices. [Diagram 34] Cs-corrected high-resolution TEM image of a cross section of CAAC-OS, and a schematic cross-sectional diagram of CAAC-OS. [Diagram 35] Cs-corrected high-resolution TEM image of the CAAC-OS in the plane. [Diagram 36] 13A to 13C show 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. [Diagram 40] 1A and 1B are a top view and a cross-sectional view showing an example of a connection portion. [Diagram 41] FIG. 4 is a diagram illustrating the temperature dependence of resistivity. [Diagram 42] Electron diffraction pattern of CAAC-OS. [Diagram 43] FIG. 1 shows the change in the crystal part of an In-Ga-Zn oxide due to electron irradiation. [Diagram 44] Schematic diagram explaining the film formation model of CAAC-OS and nc-OS. [Diagram 45] A diagram explaining InGaZnO4 crystals and pellets. [Figure 46] Schematic diagram explaining a film formation model of CAAC-OS. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments will be described with reference to the drawings. It is possible to carry out the present invention in various forms without departing from the spirit and scope of the present invention. It will be readily understood by 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, layer thickness, or area are exaggerated for clarity. Therefore, the scale is not necessarily limited to that shown in the drawings. 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 components of the It should be noted that this is added to avoid confusion and is not intended to limit the numbers.

[0025] In addition, in this specification, the words "above" and "below" indicating the position of the components are used. The positional relationship is used for convenience in describing the drawings. The relationship changes depending on the direction in which each component is depicted. The above words and phrases 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. The drain terminal is a diode that has at least three terminals. Between the drain region or drain electrode and the source (source terminal, source region or source electrode) A current flows through the drain, the channel region, and the source. In this specification and the like, the channel region refers to a region through which a current mainly flows. The flow area.

[0027] In addition, the functions of the source and drain may differ depending on whether transistors of different polarities are used or the circuit In operation, when the direction of the current changes, the positions may be reversed. 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 "device having some electrical function." "of" is not subject to any particular restrictions as long as it enables the transmission and reception of electrical signals between connected objects. For example, "something that has an electrical effect" includes electrodes, wiring, and transistors. These devices have various functions such as switching elements, resistor elements, 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 the dial.

[0031] 1A to 1C are top views and cross-sectional views of a transistor 150 included in a semiconductor device. FIG. 1A is a top view of transistor 150, and FIG. 1B is a side view of transistor 150. 1(C) is a cross-sectional view taken along dashed line X1-Y2 in FIG. 1(A). 1A is a cross-sectional view taken along line X2. For clarity, in FIG. 1A, 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 as transistor 150 in the following figures. In some cases, some parts may be omitted. The direction of the dashed 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 a 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. In the following, the elements that form oxygen vacancies are referred to as Representative examples of impurity elements are 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 oxide semiconductor film, and oxygen vacancies are formed. The carrier density increases and the conductivity becomes higher.

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

[0036] Here, the resistance of 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 prepared. The oxide conductor film (OC_SiN x ) In the doping apparatus, argon is added to the oxide semiconductor film, and the silicon nitride film is The oxide conductor film (OC_Ar dope+SiN x ), or In the plasma processing apparatus, 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 conductive film (OC_SiN x The method for preparing the sample containing the ZnO film is as follows. A silicon oxynitride film with a thickness of 400 nm was formed on the substrate by plasma CVD, and then oxygen was pumped. 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 the sputtering method used. After heat treatment in a nitrogen atmosphere at 450°C, it was annealed in a mixed gas atmosphere of nitrogen and oxygen 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 method for preparing the sample containing A 400 nm thick silicon oxynitride film is formed on a glass substrate by plasma CVD. After the formation of the silicon oxynitride film, it is exposed to oxygen plasma to add oxygen ions to the silicon oxynitride 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 was deposited by sputtering using a 100 nm thick target. After forming a nitride film, it was heat-treated in a nitrogen atmosphere at 450°C, and then heated in a mixture of nitrogen and oxygen at 450°C. The substrate was then heat-treated in a mixed gas atmosphere. Next, a doping device was used to dope the In-Ga-Zn oxide The film was irradiated with 5×10 ions at an acceleration voltage of 10 kV. 14 / cm 2 of argon was added. Next, oxygen vacancies were formed in the In-Ga-Zn oxide film by plasma CVD. A silicon nitride film of 00 nm was formed. Next, a nitrogen and oxygen mixed gas atmosphere at 350° C. was used. It was heat treated.

[0040] Oxide conductive film (OC_Ar plasma + SiN x The preparation method of the sample 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 produce a silicon oxynitride film that releases 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 the above method, and then 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 ionized into In The oxygen vacancies were created by colliding the Zn-Ga oxide film with the Zn-Ga oxide film. A silicon nitride film with a thickness of 100 nm was formed by evaporating the nitrogen and oxygen mixture at 350° C. The heat treatment was carried out in a gas atmosphere.

[0041] Next, the results of measuring the resistivity of each sample are shown in Figure 41. The resistivity was measured using a four-terminal In FIG. 41, the horizontal axis indicates the measurement temperature, and the vertical axis indicates indicates resistivity. Also, the oxide conductor film (OC_SiN x ) measurement results are indicated by square marks, Oxide conductor film (OC_Ar doped + SiN x The measurement results of oxide conductors are shown with circles. Electrical film (OC_Ar plasma+SiN x ) The 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 was difficult to measure the resistivity of an oxide conductor film, which has a higher resistivity than an 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 at temperatures between 80K and 290K. The resistivity variation is less than ±20% between 150K and 250K. The rate is less than ±10%. In other words, oxide conductors are degenerate semiconductors, and the conduction band edge and the ferroelectric It is estimated that the luminescence level of the oxide conductor film is equal to or approximately equal to the luminescence level of the oxide conductor film. 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 functioning as the source electrode and the drain electrode can be reduced. In addition, since the resistivity of the oxide conductor has low temperature dependence, the oxide conductor film and the source electrode and drain electrode can be easily formed. The variation 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] FIG. 2 shows an enlarged view of the oxide semiconductor film 106 and its vicinity. 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 may be 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 materials contained in the conductive film 110 and the conductive film 112. In addition, oxygen vacancies are formed in the oxide semiconductor film. In some cases, the conductive film 112 may be mixed with the conductive material. As a result, the region 106a in contact with the conductive film 110 and the conductive film 112 becomes more conductive, and the They function as source and drain regions.

[0046] The regions 106b and 106c function as low resistance regions. The region 106c contains an impurity element. 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. In this case, 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 gas is added. Region 106a and region 106d may be doped with a different rare gas element.

[0048] Impurity elements are boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, or In the case of chlorine, the impurity element is present only in the regions 106b and 106c. Compared with the regions 106a and 106d, the regions 106b and 106c have a higher impurity content. In the regions 106b and 106c, the concentration of oxygen is high. (SIMS: Secondary Ion Mass Spectrometry) The resulting impurity element concentration 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 5×10 19 atoms / cm 3 5×10 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 5×10 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, regions 106b and 106c become more conductive and have a lower 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 Due to interaction with one or more of the elements, regions 106b and 106c become more conductive. There may be cases where this occurs.

[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 film 110 and the conductive film 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 functioning as a channel and Between the region 106a functioning as the source region and the drain region, The channel, source and drain regions are formed in a region 106b and a region 106c, which function as a gate. The resistance between the transistor 150 and the on-state current is large. High field effect mobility.

[0056] In addition, in the manufacturing process of the transistor 150, the conductive film 11 functioning as a gate electrode 4, and a conductive film 110 and a conductive film 112 which function as a source electrode and a drain electrode are formed at the same time. 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 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 so.

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

[0058] Other configurations shown in FIG. 1 will be described in detail below.

[0059] Various substrates can be used as the substrate 102 and are not limited to a specific one. Examples of the substrate include a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), a SO I substrate, glass substrate, quartz substrate, plastic substrate, metal substrate, stainless steel substrate , Substrate with Stainless Steel Foil, 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 substrates, lamination films Examples of the materials and base films are as follows: Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulf For example, there are plastics such as polyether ether sulphate (PES). Synthetic resins, etc. Examples include polypropylene, polyester, and polyfluorine. Examples of such materials include polyvinyl chloride, polyvinyl chloride, and polyamide. Imide, aramid, epoxy, inorganic deposition film, paper, etc. In particular, semiconductor By manufacturing transistors using substrates, single crystal substrates, or SOI substrates, etc. , small variation in characteristics, size, or shape, high current capability, small size It is possible to manufacture transistors. Circuits are constructed using such transistors. As a result, it is possible to reduce the power consumption of the circuit or to increase the degree of integration 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 a semiconductor device is partially or entirely completed on the substrate, the semiconductor device is separated from the substrate 102 and another In this case, the transistors are transferred to a substrate with poor heat resistance or a flexible substrate. The transfer can also be performed on a flexible substrate. The above-mentioned release layer may be, for example, a tungsten film and a silicon oxide film. The laminated structure of the inorganic film with the silicon film, or the organic resin film such as polyimide is 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, Rubber substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, hemp), synthetic fibers (nylon) , polyurethane, polyester) or regenerated fibers (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 is possible to form, manufacture devices that are less likely to break, are heat resistant, or are lighter or thinner. .

[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 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 can prevent the insulating film 104 and the oxide semiconductor from The interface state at the interface with the conductive 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 nitrogen. 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 multilayer.

[0065] The oxide semiconductor film 106 is typically made of In-Ga oxide, In-Zn oxide, or 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] In addition, 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 % or more 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 3 nm or more and 200 nm or less, or 3 nm or more and 100 The thickness can be 3 nm or less, or 3 nm to 50 nm.

[0069] In the case where the oxide semiconductor film 106 is an In-M-Zn oxide, the In-M-Zn oxide is formed. 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 The atomic ratio of n:M:Zn to Zn is preferably 3:1:2. The atomic ratios are calculated based on the atomic ratio of the metal elements contained in the sputtering target. This includes a fluctuation 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. When the oxide semiconductor film 106 is filled with oxygen, oxygen vacancies are increased in the oxide semiconductor film 106, and the oxide semiconductor film 106 becomes n-type. Therefore, the oxide semiconductor film 106 has a high concentration of silicon and carbon, particularly in the region 106d. The concentration (obtained by secondary ion mass spectrometry) was calculated as 2×10 18 atoms / cm 3 Below Down, or 2×10 17 atoms / cm 3 As a result, the following can be achieved: A 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 2×10 16 atoms / cm 3 The following can be done: When alkaline metals and alkaline earth metals combine with oxide semiconductors, they generate carriers. Therefore, the off-state current of the transistor may increase. It is preferable to reduce the concentration of alkali metals or alkaline earth metals in the A transistor has electrical characteristics in which the threshold voltage is positive (also called normally-off characteristics). has.

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

[0073] The impurity elements in the oxide semiconductor film 106, particularly in the region 106d, are reduced. 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 The following also is 1×10 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 such a material, a transistor having better electrical characteristics can be manufactured. Here, a high-purity pure silicon has a low impurity concentration and a low defect level density (few oxygen vacancies). High-purity intrinsic or substantially high-purity intrinsic oxides Semiconductors have few carrier generation sources, so it is sometimes possible to reduce the carrier density. Therefore, a transistor in which a channel region is formed in the oxide semiconductor film has a threshold voltage 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 intrinsic has a low density of defect states; The trap density may also be lower. A certain oxide semiconductor film has a remarkably small off-state current and a voltage between the source and drain electrodes ( In the drain voltage range of 1V to 10V, the off-state current is Below the measurement limit of 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 low fluctuation in electrical characteristics. In some cases, this can result in a transistor with low resistance and high reliability.

[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), 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. A mixed film having two or more of the following regions may be used: a region of a CAAC-OS structure, a region of a single crystal structure, and a region of a crystalline structure. 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 of either AC-OS or single crystal structure In addition, 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.

[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 is caused to 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. Note that 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 insulating layer 11 may be formed of a single layer or a multilayer structure, such as a -Zn oxide.

[0079] In addition, an insulating film having a blocking effect against oxygen, hydrogen, water, etc. is provided as the insulating film 108. By this, oxygen can be diffused from the oxide semiconductor film 106 to the outside, and oxygen can be absorbed 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 having such properties 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 of 100K or less 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 .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 set to X-band. The ESR measurement of the ZnO-based ... 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 is 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 in the ESR spectrum below 100K is 2.037 to 2.039. The first signal has a g value of 2.001 to 2.003, and the second signal has a g value of 1 The third signal, between .964 and 1.966, is nitrogen oxide (NO x , x is 0 to 2 This corresponds to signals caused by g values ​​of 2.037 or more and 2.038 or less. a first signal with a g value of 0.39 or less, a second signal with a g value of 2.001 to 2.003 or less, And 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 concentration of nitrogen oxide in the silicon oxynitride film, the smaller the content of nitrogen oxide 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 having few defects. By using a silicon nitride film, nitrogen oxide is less likely to be generated, and the oxide semiconductor film 1 It is possible to reduce carrier traps at the interface between the gate insulating film and the semiconductor substrate. It is possible to reduce the shift in the threshold voltage of a transistor included in a semiconductor device. Therefore, the fluctuation in the electrical characteristics of the transistor can be reduced.

[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 may be 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, It can be formed by using an alloy of a combination of metal elements. Alternatively, the conductive film 1 may be made of a metal element selected from one or more of the following: 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, A two-layer structure with a titanium film laminated on an aluminum film, and a titanium film laminated on a titanium nitride film A two-layer structure with a tungsten film on a titanium nitride film, a two-layer structure with a tantalum nitride film or a two-layer structure in which a tungsten film is laminated on a tungsten nitride film; 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 is formed by forming a titanium film on top of the titanium film, laminating a copper film on a copper film containing manganese, and There are three-layer structures, such as a copper film containing manganese on top of the 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 (ITO). 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. In addition, a laminate structure of the conductive material having light transmitting properties and the metal element may be used. It can also be written as:

[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 from 100 nm to 400 nm.

[0089] The insulating film 116 is formed by using a single layer or a stacked layer 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, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitrogen. 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 multilayer.

[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 oxynitride, or aluminum oxide. The above may be used, and the layer may be formed as a single layer or a multilayer.

[0092] The thickness of the insulating film 116 and the insulating film 118 are each 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. 3(A) is a cross-sectional view taken along dashed line X1-Y2 of FIG. Cross-sectional view of section X2.

[0095] The transistor 151 illustrated in FIG. 3 includes a conductive film 110, a conductive film 112, and a conductive film 114. The insulating film 104 is a nitride insulating film 10. The insulating film 104a and the oxide insulating film 104b are stacked on top of each other. It is similar to the transistor 150 and has the same effect.

[0096] First, the conductive film 110, the conductive film 112, and the conductive film 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] Like the conductive film 110, the conductive film 112 includes a conductive film 112a, a conductive film 112b, and a conductive 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 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 alloys thereof, or titanium nitride The insulating layer 11 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 in contact with the insulating film by heat treatment. The coating film may be formed of a compound containing X. An example of the compound containing X is The oxides are X oxide, In-X oxide, Ga-X oxide, In-Ga-X oxide, 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 blocking film 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 functioning 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 oxide semiconductor film 107 can be reduced. As a result, a transistor with an excellent subthreshold swing value (S value) can be fabricated. 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 film 110b, the conductive film 112b, and the conductive film 114b are formed of copper, aluminum, or the like. It can be formed using a single metal such as gold or silver, or an alloy thereof, 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 element contained in the conductive film 114b is passivated. The metal elements contained in the conductive film 110b, the conductive film 112b, and the conductive film 114b are In this way, the conductive film 6 can be prevented from moving to the oxide semiconductor film 106 in the formation process of the conductive film 6. The conductive film 110c, the conductive film 112c, and the conductive film 114c may be made of a metal silicide or a 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 film 110b, the conductive film 112b, and the conductive film 114b are formed using copper. The conductive film 110c, the conductive film 112c, and the conductive film 114c are made of CuSi x N y (x>0, y>0).

[0106] The conductive film 110b, the conductive film 112b, and the conductive film 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. And the oxide on the surface of the conductive film 114b is reduced.

[0107] Next, the conductive film 110b, the conductive film 112b, 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 to decompose the silane into Si and H2. In addition, CuSi was 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 film 110b, the conductive film 112b, and the conductive film 114b are immersed in ammonia or nitrogen. By exposing the conductive film 110b and the conductive film 110c to plasma generated in an atmosphere containing nitrogen such as 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. S 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 annealed. After exposure to plasma generated in an atmosphere containing ammonia or nitrogen, etc., the specimen is heated to 200°C or higher. While heating at 400° C. or less, the conductive film 110b, the conductive film 112b, and the conductive film 114b are 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 I will explain it below.

[0111] For example, the nitride insulating film 104a may be made of silicon nitride, silicon oxynitride, or aluminum nitride. The oxide insulating film 10 can be formed using aluminum, aluminum nitride oxide, or the like. The layer 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, hydrogen, water, etc. from the outside can be prevented. 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. FIG. 4A is a top view of the transistor 152, and FIG. 4B is a side view of the transistor 152. 4(C) is a cross-sectional view taken along 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 dividing the oxide semiconductor film 1 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 a similar effect.

[0115] The oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 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 film 107a and the oxide semiconductor film 107c are typically made of In-G a oxide, In-Zn oxide, In-Mg oxide, Zn-Mg oxide, In-M-Zn oxide (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 and the energy difference between the conduction band minimum of the oxide semiconductor film 107b and the energy difference between the conduction band minimum of the oxide semiconductor film 107b and the Above, 0.07 eV or more, 0.1 eV or more, or 0.2 eV or more and 2 eV or less, 1e 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. The atomic ratio of the metal elements in the target used for this purpose 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; It is preferable that z1 / y1 is 1 / 3 or more and 6 or less, and more preferably 1 or more and 6 or less. When z1 / y1 is 1 or more and 6 or less, 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. There are cases such as 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 film 107a and the oxide semiconductor film 107c are In-M-Zn oxides (M represents Mg, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf), for the targets used to form the oxide semiconductor film 107a and the oxide semiconductor film 107c, if the atomic ratio of the metal elements is In:M:Zn = x2:y2:z2, then x2 / y2 、 is < x1 / y1, and z2 / y2 is preferably 1 / 3 or more and 6 or less, more 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 film 107 a and the oxide semiconductor film 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, In: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. Also, when the oxide semiconductor film 107a and the oxide semiconductor film 107c are In-Ga oxides For example, it can be formed by a sputtering method using an In-Ga metal oxide target (In:Ga = 7:93). Also, the oxide semiconductor film 107a and the oxide semiconductor

[0119] film 107c can be formed by a sputtering method using an In-Ga metal oxide target (In:Ga = 7:93). Also, the oxide semiconductor film 107a and the oxide semiconductor The In-Ga oxide film 107c is formed by a sputtering method using DC discharge. The target is In:Ga=x:y [atomic ratio], 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 according to the required semiconductor characteristics. Just use what you have.

[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 Alternatively, an In-Ga-Zn oxide having the above ratio may 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 more than 3nm or more than 100nm or less, or more than 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 so.

[0125] The oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107c Each interface is a scanning transmission electron microscope (STEM). In some cases, 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 surface and the lower surface of the oxide semiconductor film 107b. In this way, oxygen vacancies in the oxide semiconductor film 107b can be reduced. The oxide semiconductor film 107b includes 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. 7a and the oxide semiconductor film 107b, and the interface between the oxide semiconductor film 107b and the oxide semiconductor film 10 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 layer contacts an insulating film containing the insulating film, an interface state is formed, and the interface state forms a channel. In such a case, 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, This makes it possible to 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, which reduces the field effect mobility of the transistor. The oxide semiconductor film 107b is made of an oxide semiconductor film 107c containing one or more metal elements. Since the oxide semiconductor film 107b is provided in contact with the oxide semiconductor film 107b, At the interface with the film 107c, carrier scattering is unlikely to occur, and the field effect mobility of the transistor is can be increased.

[0130] The oxide semiconductor film 107a and the oxide semiconductor film 107c are formed by the insulating film 104 and the insulating The constituent elements of the film 108 or 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 into the oxide semiconductor film 107a and the oxide semiconductor film 107c. Impurities such as silicon and carbon may enter the oxide film from the interface to a depth of a few nm. When the impurity enters the semiconductor film 107b, it forms an impurity level, which becomes a donor and generates electrons. This can sometimes result in n-type doping.

[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 nm, impurities such as silicon and carbon may reach the oxide semiconductor film 107b. Since the impurity level does not reach the threshold, the influence of the impurity level is reduced.

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

[0134] FIG. 5 shows a transistor having 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. 5(A) is a cross-sectional view taken along dashed line X1-Y2 of FIG. 5(A), and FIG. 5(C) is a cross-sectional view taken along dashed line X1-Y2 of FIG. Cross-sectional view of section X2.

[0136] In a transistor 153 illustrated in FIG. 5, the oxide semiconductor film 106 is in contact with the insulating film 104. The oxide semiconductor film 107b is 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. 1(A) is a band structure of the transistor 153 shown in FIG. , the insulating film 104, the oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 1 11(B) and the energy (Ec) of the conduction band minimum of the insulating film 108. ) is the band structure of the transistor 154 shown in FIG. Conduction of the film 104, the oxide semiconductor film 107b, the oxide semiconductor film 107c, and the insulating film 108 The energy (Ec) of the lower 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. The oxide semiconductor film 107a, the oxide semiconductor film 107b, and the oxide semiconductor film 107c are formed. This can also be understood from the fact that oxygen easily diffuses between the two materials due to the common elements that make them up. 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 laminated with a common main component, is not simply laminated, but is formed continuously. Junction (here, specifically, a U-shaped well in which the energy of the conduction band edge changes continuously between layers) The U-shape well structure is formed at the boundary between the layers. In the oxide semiconductor, defect states such as trap centers and recombination centers, or carrier The laminated structure is formed so that there are no impurities that can impede the flow of oxygen. When impurities are present between the 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 of the oxide semiconductor film 107a and the Ec of the oxide semiconductor film 107c are Although similar cases are shown, they may be different.

[0141] As shown in FIG. 11A, the oxide semiconductor film 107b serves as a well, and the transistor 1 In FIG. 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 are in a conduction band. Since the energy at the bottom changes continuously, a U-shaped well structure channel is buried in the It can also be called Nell.

[0142] As shown in FIG. 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 transistor 1 In FIG. 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 including one kind of metal element. Since the oxide semiconductor film 107a and the oxide semiconductor film 107c each include the above, , 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 unlikely to be formed at the interface between the oxide semiconductor film 107c and the oxide semiconductor film 107b. By providing the organic 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 including one kind of metal element. Since the oxide semiconductor film 107c contains the above-mentioned oxide semiconductor film, Therefore, the interface state is unlikely to be formed at the interface with the oxide semiconductor film 107b. By providing 107c, the variation of 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. FIG. 6A is a top view of the transistor 154, and FIG. 6B and FIG. 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. 1 is a cross-sectional view taken along dashed 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 the same effects are achieved.

[0149] The conductive film 114 and the conductive film 120 are not connected, and different potentials are applied to each of them. The threshold voltage of the transistor 154 can be controlled. An example of a cross-sectional view in this case is shown in FIG. In addition, when the conductive film 114 and the conductive film 120 are not connected, 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 variation is reduced, and -GBT (-Gate Bias -Temperature) stress test degradation suppression and at different drain voltages In addition, the oxide semiconductor film 106 can suppress a change in the on-state current rising voltage. In the SiO2 film, the area through which the 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 channel length of the transistor is set to less than 2.5 μm or 1.45 μm or more. By making the thickness 0.2μm 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 the conductive film 120.

[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 such a case is shown in FIG. 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 deposition method, pulsed laser deposition (PLD) method Alternatively, the film can be formed by a coating method or a printing method. Representative 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 set to atmospheric pressure or reduced pressure, and the source gas and the oxidizing agent are simultaneously 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 set at atmospheric pressure or reduced pressure, and the source gas for the reaction is The gases are introduced into the chamber in sequence, and the film is formed by repeating the gas introduction sequence. For example, By switching each switching valve (also called high-speed valve), two or more types of raw materials can be The source gases are sequentially supplied to the chamber, and the first source gas is supplied to the chamber so that multiple source gases do not mix. Simultaneously with or after the second gas, an inert gas (such as argon or nitrogen) is introduced. Introduce the raw material 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. Also, instead of introducing an inert gas, the first source gas is discharged by 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 controlled and repeated several times 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. This allows precise film thickness control, making it possible to fabricate minute transistors. It is suitable for fabrication.

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

[0158] The insulating film 104 is formed by a method such as sputtering, CVD, vapor deposition, or pulsed laser deposition (PLD). The insulating film 102 may be formed by using a suitable method such as a printing method or a coating method. After the film is formed, 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. In addition, a film that suppresses oxygen desorption is formed on the insulating film, and then 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 lower, or at 200°C to 240°C, and the raw material gas is introduced into the treatment chamber. The pressure in the treatment chamber is set to 100 Pa or more and 250 Pa or less, or 100 Pa or more and 200 Pa or less. The electrode in the treatment chamber is set at 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 membrane 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 described with reference to FIG. 7(A) and FIG. 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. 7B, 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 is made of aluminum, chromium, tantalum, titanium, molybdenum, etc. A metal element selected from the group consisting of arborene, nickel, iron, cobalt, and tungsten, and the above-mentioned metals. Alloys containing the above elements, alloys combining the above metal elements, alloys having the above metal elements a metal nitride having the above-mentioned metal element; a metal oxide having the above-mentioned metal element; The insulating film is formed using a conductive material such as an oxide.

[0164] The thickness of the film 119 for suppressing 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 method of adding oxygen 121 to the insulating film 103 through the film 119 is 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 processing, the oxygen is excited by microwaves to produce high-density oxygen. By generating atomic 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). In addition, the insulating film 104 can be formed by adding sufficient oxygen after the film formation. In the case where the insulating film 104 having the above-mentioned structure can be formed, the process of adding oxygen shown in FIG. This does not have to be done.

[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 the mask is formed, part of the oxide semiconductor film is etched using the mask. As shown in FIG. 1D, the oxide semiconductor film 106 can be formed. After that, the mask is 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, an oxide semiconductor film having element separation can be formed. 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 The device may be an RF power supply device, an AC power supply device, a DC power supply device, or the like. CAAC-OS films can be formed by using an AC or DC power supply. It is also possible to form an oxide semiconductor film by sputtering using an RF power supply. In contrast, an oxide semiconductor film is formed by a sputtering method using an AC power supply or a DC power supply. It is preferable to form the film having a uniform thickness, composition, or crystallinity. stomach.

[0172] The sputtering gas is a rare gas (typically argon), oxygen, or a mixture of a rare gas and oxygen. In the case of a mixture of rare gas and oxygen, the amount of oxygen gas is appropriately adjusted relative to the amount of rare gas. 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, Temperature: 150℃ to 750℃, 150℃ to 450℃, or 200℃ An oxide semiconductor film is formed at a temperature of 350° C. or lower to form a CAAC-OS film. In addition, by setting the substrate temperature at 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 order to form a CAAC-OS film, which will be described later, it is preferable to apply the following conditions: It is 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 may 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 is reduced. The oxygen ratio in the deposition gas is preferably 30% by volume or more, or 100% by volume or more. %.

[0178] In addition, 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. Or, 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 The heating is performed in an inert gas atmosphere containing nitrogen, or after heating in an inert gas atmosphere, the heating is performed in an oxygen atmosphere. The inert atmosphere and oxygen atmosphere may contain hydrogen, water, etc. The treatment time is preferably from 3 minutes to 24 hours.

[0180] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, heat treatment can be performed at a temperature above the distortion 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 5×10 17 atoms / cm 3 or less, or 1×10 16 atoms / cm 3 It can be as follows:

[0182] The deposition equipment using ALD can be used to form oxide semiconductor films, such as InGaZnO 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 gas 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 InZnO2 layer, GaInO layer, ZnInO layer, GaZnO layer, etc. Alternatively, instead of O3 gas, H2O gas bubbled with an inert gas such as Ar may be used. However, it is preferable to use O3 gas that does not contain H. In(CH3) Instead of the gas In(C2H5)3, gas Ga(CH3)3 may be used. Alternatively, Ga(C2H5)3 gas may be used. Zn(CH3)2 gas may also be used. This is also 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 manner, the oxide semiconductor film 106 is formed.

[0184] The heat treatment should be performed at a temperature between 350℃ and 650℃, or between 450℃ and 600℃. By doing this, the CAAC conversion rate described below can be reduced to 60% or more but less than 100%, or 80% or more but less than 100%. 00%, or between 90% and 100%, or between 95% and 98%. In addition, an oxide semiconductor film in which the content of hydrogen, water, and the like is reduced 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 using the method for forming the insulating film 104 as appropriate.

[0186] As the insulating film 108, a silicon oxide film or a silicon oxynitride film is formed 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. Representative examples of deposition gases containing silicon include silane, diphenyl ether, and dimethyl ether. Examples of oxidizing gases include oxygen, ozone, monooxygen, and silane. 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 less. times, or between 40 and 80, and the pressure in the treatment chamber is less than 100 Pa, or 50 Pa By using a CVD method with a thickness of 0.1 to 1.0 mm, a silicon oxynitride film with fewer defects can be formed. This can be done.

[0188] In addition, 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 a source gas is introduced into the processing chamber. The pressure in the chamber is set to 20 Pa or more and 250 Pa or less, and 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 the case of the electron beam, 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. Therefore, the insulating film 108 is formed with less defects due to less plasma damage to the deposition surface and deposits. It is possible.

[0190] The insulating film 108 can be formed by a CVD method using an organic silane gas. The organic silane gas is 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 may be formed.

[0191] In addition, 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 (e.g., Hafnium alkoxide solution, typically tetrakisdimethylamidohafnium (TDMA) Two types of gases are used: vaporized nitrogen oxide (NO3) as a raw material gas and ozone (O3) as an oxidant. 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 The raw gas is vaporized (e.g., trimethylaluminum (TMA)) and H2O is used as an oxidizer. Two types of gas are used. The chemical formula for trimethylaluminum is Al(CH3)3. Other liquid materials include tris(dimethylamido)aluminum and triisobutyrate. Aluminum tris(2,2,6,6-tetramethyl-3,5-hepta) By forming the film using the ALD method, the coating rate is high and the film thickness is thin. 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 It removes the chlorine contained in the water and supplies radicals of oxidizing gases (O2, nitrous oxide) to adsorb the substances. and react with.

[0195] Here, a silicon oxynitride film is formed as the insulating film 108 by the plasma CVD method. 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 so that part of the oxide semiconductor film 106 is exposed. An opening 140a and an opening 140b are formed.

[0197] The method for etching the insulating film 108 is a wet etching method or / and a dry etching method. The Ching method can be used as appropriate.

[0198] Next, as shown in FIG. 8B, a conductive film 1 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 inserted, the electrical characteristics of the transistor may be deteriorated. By forming the insulating film 108 before forming the insulating film 109, the channel of the oxide semiconductor film 106 is 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. The amount can be reduced.

[0200] The conductive film 109 can be formed by a sputtering method, a vacuum deposition method, a pulsed laser deposition (PLD) method, or the like. 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 by a film forming apparatus using ALD. In this case, WF6 gas and B2H6 gas are repeatedly introduced in sequence to obtain the initial temperature. 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. 8C, 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 an 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 structure contains the same metal, in other words, the same metal element.

[0203] The conductive film 109 is etched by a wet etching method or / and a dry etching method. 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 the Therefore, leakage current between the conductive film 114 functioning as a conductive film 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 be formed by electrolytic plating, printing, inkjet printing, or the like.

[0205] Next, as shown in FIG. 8D, the oxide semiconductor film 106 is treated with the mask 111. 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 formed. 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. Impurity elements can be added by generating a plasma and performing a plasma treatment. 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 gas for the impurity element 117 is B2H6, PH3, CH4, N2, 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, 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 H and and hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, and chlorine. One or more of the above can be added to the oxide semiconductor film 106 at the same time.

[0208] Alternatively, a rare gas is added to the oxide semiconductor film 106, and then 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 doping of the impurity element 117 is controlled by appropriately setting implantation conditions such as acceleration voltage and dose amount. For example, when argon is added by ion implantation, the acceleration voltage is 10 kV and the doping The amount of deviation is 1×10 13 ions / cm 2 More than 1×10 16 ions / cm 2 Let's say the following: For example, 1×10 14 ions / cm 2 In addition, phosphorus can be implanted by ion implantation. When doping with 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 diagram of the region where the impurity element is added is shown in Figure 10(A), (B), and (C). 1B and 1C are enlarged views of the oxide semiconductor film 106 and its vicinity.

[0212] As shown in FIG. 10A, the region where the impurity element 117 is added is formed by the insulating film 104, the oxide semiconductor In some cases, the oxide semiconductor film 106 is formed on the conductive film 106 and the insulating film 108. In the depth direction of the region where the doped region is exposed, an end portion 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 107. This is the direction proceeding from 108 toward the insulating film 104.

[0213] Alternatively, as shown in FIG. 10B, the region to which the impurity element 117 is added is an oxide semiconductor film. Note that, when the oxide semiconductor film 106 is exposed, In the depth direction of the doped region, an end 136 of the doped region is adjacent to the insulating film 104 and the oxide semiconductor film It is located at the interface of 106.

[0214] Alternatively, as shown in FIG. 10C, the region to which the impurity element 117 is added is an oxide semiconductor film. Note that, when the oxide semiconductor film 106 is exposed, 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. 2 can be formed. is added to the oxide semiconductor film 106 through the insulating film 108, compared with the region 106b. As a result, the concentration of the impurity element is low. 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 film 4 as a mask.

[0217] After that, a heat treatment is performed to further increase the conductivity of the region to which the impurity element 117 is added. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate distortion point, or 250° C. or lower. ℃ 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 are 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 film 116 and the insulating film 118 are formed by appropriately using the method for forming the insulating film 104 and the insulating film 108. There can be.

[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 treatment 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 treatment 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 formed. A silicon film can be formed as the insulating film 116 .

[0221] Alternatively, over the oxide semiconductor film 106, the conductive film 110, the conductive film 112, and the conductive film 114, After forming an aluminum film or an aluminum oxide film, a heat treatment is performed to form the aluminum film. In the region 106b, oxygen contained in the oxide semiconductor film 106 is oxidized to an 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 to which the impurity element 117 is added. The temperature of the heat treatment is typically 150° C. or higher and lower than the substrate distortion point, or 250° C. or lower. ℃ 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. The conductive film 110, the conductive film 112, and the conductive film 110c included in the conductive film 114 of 151, and forming the conductive film 112c and the conductive film 114c, and adding an impurity element 1 to the oxide semiconductor film 106. The step of adding 17 will now be described.

[0225] 7 and 8(A) to 8(C), an insulating film 104 and an oxide film 105 are formed on a substrate 102. The 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] The mask 111 is then 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 to form a conductive film. The oxides on the surfaces of the film 110b, the conductive film 112b, and the conductive film 114b are reduced. While heating at a temperature of 00° C. or more and 400° C. or less, the conductive film 110b, the conductive film 112b, and the conductive film Next, the conductive film 110b, the conductive film 112b, and the conductive film 114b are exposed to silane. The conductive material is exposed 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 ammonia or nitrogen. Nitrogen and / or hydrogen are added to the oxide semiconductor film 106 due to the exposure to plasma. 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 a conductive film 110, a conductive film 112, and a conductive film 114. Since there is no overlap, it is possible to reduce 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 transistors 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 thereto. For example, a channel or 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 having, for example, GaAs (gallium arsenide).

[0234] The structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiment modes. They can be used in combination.

[0235] (Embodiment 2) In this embodiment mode, one mode of a semiconductor device and a manufacturing method thereof will be described with reference to FIGS. In this embodiment, the low resistance region is formed in a semiconductor device in a semiconductor device according to 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 12A is a top view of a transistor 190, and FIG. 12(A) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 12(A), and FIG. 12(C) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 1 is a cross-sectional view taken along dashed 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. A semiconductor film 166, an insulating film 168 in contact with the semiconductor film 166, and an opening of the insulating film 168. 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 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 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. In the following, the elements that form oxygen vacancies are referred to as Representative examples of impurity elements include hydrogen and rare gas elements. Representative examples of rare gas elements are helium, neon, argon, krypton and xenon. In addition, impurity elements such as boron, carbon, nitrogen, fluorine, aluminum, and silicon The oxide semiconductor film 166 may contain elements such as nitrogen, 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 converted into 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 electrical conductivity of the oxide semiconductor film is increased by the interaction between oxygen vacancies and hydrogen. When hydrogen enters the oxygen vacancies in the semiconductor film, electrons are generated as carriers. This results in a high electrical conductivity.

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

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

[0244] The regions 166b and 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 the case where the region 166c has a rectangular shape, a 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 the rare gas element. 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 not included in the oxide semiconductor film 166. 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 vacancies in the regions 166b and 166c can be controlled. When the amount of hydrogen is relatively large, the amount of oxygen vacancies in the regions 166b and 16 The carrier density of the region 166b and the region 166c can be controlled. Carrier density 5×10 18 pieces / cm 3 More than 1×10 19 pieces / cm 3 That's all. More preferably, 1×10 20 pieces / cm 3 By setting the above, the channel, source region, and drain It is possible to fabricate transistors with small resistance between the drain region and the gate, and large on-state current. It is.

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

[0248] In the regions 166b and 166c, hydrogen is obtained by secondary ion mass spectrometry. The concentration is 8 x 10 19 atoms / cm 3 or more, or 1×10 20 atoms / cm 3 or more, or 5×10 20 atoms / cm 3 In addition, the area 16 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 5×10 18 atoms / cm 3 or less, or 1×10 18 atoms / cm3 Less than or equal to 5x 10 17 atoms / cm 3 or less, or 1×10 16 atoms / cm 3 The following This can be done.

[0249] In addition, impurity elements include boron, carbon, nitrogen, fluorine, aluminum, silicon, and lithium. 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, only 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 5×10 19 a toms / cm 3 5×10 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 channel region 166d. As a result, a transistor having normally-off characteristics can be manufactured.

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

[0255] The transistor 190 in this embodiment has a region 166d functioning as a channel and Between the region 166a functioning as the source region and the drain region, The channel, source and drain regions are formed in a region 166b and a region 166c, which function as a gate. The resistance between the transistor 190 and the on-state current is large. 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 are formed at the same time. 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. In this case, the signal delay in the conductive film 170, the conductive film 172, and the conductive film 174 is reduced. It is possible.

[0257] In the transistor 190, the conductive film 170, the conductive film 172, and the conductive film 174 A rare gas element is added to the oxide semiconductor film 166 using the mask, whereby 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 regions 166b and 166c. By adding hydrogen, oxygen vacancies are formed and hydrogen is added. It is possible to increase the conductivity in the regions 166b and 166c, and to 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 for the insulating film 104 in Embodiment 1. can be done.

[0262] The oxide semiconductor film 166 can be formed using the material shown in the oxide semiconductor film 106 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 in Embodiment 1. can be done.

[0264] The conductive films 170, 172, and 174 can 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 in Embodiment 1. 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 14A is a top view of a transistor 191, and FIG. 14(A) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 14(A), and FIG. 14(C) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 1 is a cross-sectional view taken along dashed line X1-X2.

[0269] A transistor 191 illustrated in FIG. 14 includes a conductive film 170, a conductive film 172, and a conductive film 174. Each of the insulating films 164 is characterized by having a three-layer structure. The insulating film 164a and the oxide insulating film 164b are stacked on top of each other. It is similar to transistor 190 and provides the same effect.

[0270] First, the conductive film 170, the conductive film 172, and the conductive film 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 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 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 can be formed by the same method as 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 Metal elements contained in the conductive film 172b and the conductive film 174b diffuse into the oxide semiconductor film 166. Materials that prevent this can be used appropriately.

[0275] The conductive films 170b, 172b, and 174b can be formed by the same method as described in Embodiment 1. Similar to the conductive film 110b, the conductive film 112b, and the conductive film 114b, a low-resistance material is appropriately used. It is possible.

[0276] The conductive films 170c, 172c, and 174c can be formed by the same method as 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 the following from happening:

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

[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 15A is a top view of a transistor 192, and FIG. 15(A) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 15(A), and FIG. 15(C) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 1 is a cross-sectional view taken along dashed 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 in contact with the insulating film 164. 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 similar to those of the transistor 190. It has a similar 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, which are described in Embodiment 1, 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 surface and the lower surface of the oxide semiconductor film 167b. By this, oxygen vacancies in the oxide semiconductor film 167b can be reduced. The oxide semiconductor film 167b includes one or more metal elements constituting the oxide semiconductor film 167b. Since 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] In addition, by providing the oxide semiconductor film 167a, the threshold voltage of the transistor and the like can be reduced. It is possible to reduce the variation in electrical characteristics.

[0285] In addition, the oxide semiconductor film 167b includes 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 At the interface with the semiconductor film 167c, carrier scattering is unlikely to occur, and the field effect of the transistor is The resultant mobility can be increased.

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

[0287] From the above, the transistor described in this embodiment has the following electrical characteristics, such as a 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 16A is a top view of a transistor 193, and FIG. 16(A) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 16(A), and FIG. 16(C) is a cross-sectional view taken along dashed line Y1-Y2 in FIG. 1 is a cross-sectional view taken along dashed line X1-X2.

[0290] In a transistor 193 illustrated in FIG. 16 , an oxide semiconductor film 166 is The oxide semiconductor film 167b is in contact with the insulating film 168. 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 17A is a top view of a transistor 194, and FIG. FIG. 17(C) 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. 1 is a cross-sectional view taken along dashed line X1-X2.

[0293] A transistor 194 illustrated in FIG. 17 includes an oxide semiconductor film 166 overlapped with an insulating film 164 interposed therebetween. That is, the conductive film 181 is a gate electrode. The transistor 194 is a transistor having 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 each of 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 to the conductive film 174 and the conductive film 181. This reduces the initial characteristic variation, suppresses deterioration during -GBT stress testing, and It is possible to suppress the fluctuation of the on-current rising voltage in the drain voltage. In the semiconductor film 166, the area in which carriers flow becomes larger in the film thickness direction. As a result, the on-current of the transistor 194 increases and , high field effect mobility. 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 The resultant mobility can be increased.

[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. FIG. 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. 26(A) to 26(C) are cross-sectional views taken along dashed line X1-X2 of the semiconductor device. 26A and 26B are 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 dashed line Y1-Y2 in FIG. FIG. 26(C) is a cross-sectional view taken along 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 in the transistor 150 is different from that in the transistor 150 shown in FIG. In the case of the capacitor 150A, the insulating film 108 is separated into islands. It is similar to the transistor 150 and provides 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 in the transistor 190 is different from that in the transistor 190 shown in FIG. In the case of the first electrode 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 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 transistor 190 shown in FIG. 12, the insulating film 108 or the insulating film 168 In the case of using a structure in which the oxide semiconductor film is not separated into islands, the oxide semiconductor film 106 or the oxide semiconductor film 16 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 above 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 conductive film 110 functioning as a source electrode and a drain electrode; The conductive film 112 that functions as a conductive layer is structured so that at least a portion 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 conductive film 170 functioning as a source electrode and the conductive film 172 functioning as a drain electrode are , at least a portion of which 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. In FIG. 38(B), the oxide semiconductor film 166 is doped with an impurity element. 38A is a schematic diagram of a transistor 190B. The cross-sectional views in the direction are shown in FIG. 12(A) and FIG. 12(B). Since this is similar to 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 film 170, the conductive film 172, and the conductive film 174 of the transistor 190 are The structure of the transistor 190B shown in FIG. 90 has insulating films 168, 176, and 178. In the transistor 190B illustrated 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 The edge of the insulating film 178 has a curvature. 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 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 closer to the conductive film 172e than the conductive film 172d. The end of the conductive film 174 is protruding outward. The conductive film 170 and the conductive film 174d have an end portion that protrudes outward. The conductive film 172 and the conductive film 174 have a two-layer structure, and the conductive film in the lower layer protrudes. By forming the lower conductive film into a protruding shape, it is possible to In some cases, the underlying conductive film can suppress the passage of impurities.

[0306] The conductive film 170, the conductive film 172, and the conductive film 174 can be processed, for example, by A dry etching method is used. The conductive film 170 and the conductive When the insulating film 168 and the conductive film 174 are processed, 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. In the case where 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 part of the edge.

[0307] Next, referring to FIG. 38B, the oxide semiconductor of the transistor 190B shown in FIG. The following is a conceptual diagram of the film thickness direction when an impurity element is added to the film 166. 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, for example, a crystalline oxide semiconductor film, the region 166y is The crystallinity is higher than that of region 166x. The difference in crystallinity is due to the fact that when an impurity element is added, This is because the 166x will be damaged and its crystallinity will decrease.

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

[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 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. An opening 180a and an opening 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. 19C, a mask is formed on the conductive film 169 by a lithography process. After forming 111, the conductive film 169 is immersed in an etching solution and / or etching gas 167. 3, and then the conductive film 170, the conductive film 172, and the conductive film 174 are formed.

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

[0318] Note that the conductive films 170, 172, and 174 can be formed by the following method instead of the above method. It may be formed by electrolytic plating, printing, inkjet printing, or the like.

[0319] Next, as shown in FIG. 19D, 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 is doped in the region not covered by 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 shown in Embodiment 1. The method can be appropriately used.

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

[0322] As shown in FIG. 21A, the region where the impurity element 177 is added is formed by the insulating film 164, the oxide semiconductor In some cases, the oxide semiconductor film 166 is formed on the conductive film 166 and the insulating film 168. In the depth direction of the region where the doped region is exposed, an 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 an oxide semiconductor film Note that when the oxide semiconductor film 166 is exposed, In the depth direction of the doped region, an end 196 of the doped region is adjacent to the insulating film 164 and the oxide semiconductor film It is located at the interface of 166.

[0324] Alternatively, as shown in FIG. 21C, the region to which the impurity element 177 is added is an oxide semiconductor film. Note that when the oxide semiconductor film 166 is exposed, 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 An impurity element 177 may be added to the oxide semiconductor film 166 using the film 4 as a mask.

[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 76, the oxide semiconductor film 166 is damaged 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, 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 is formed on the insulating film 176. A border membrane 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) and other methods are also available. 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 semiconductor film. Since the oxygen vacancies are included in the region, a low-resistance region is formed in the oxide semiconductor film 166. Specifically, the region 166b and the region 166c shown in FIG. Note that the region 166c is formed by adding an element added 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 variation in conductivity.

[0332] After that, a 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 distortion point, or 250° C. or lower. ℃ or more and 450℃ or less, or 300℃ or more and 450℃ or less. As a result, It is possible to increase the electrical conductivity and reduce the fluctuation in the electrical conductivity of 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 treatment 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 treatment 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 formed. A silicon film can be formed as the insulating film 178.

[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. The conductive film 170c included in the conductive film 170, the conductive film 172, and the conductive film 174 of the capacitor 191; The steps of forming the conductive films 172c and 174c and adding an impurity element to the oxide semiconductor film 166 The process for adding 177 will now 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 a mask 111 is formed.

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

[0339] The mask 111 is then 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 to form a conductive film. The oxides on the surfaces of the film 170b, the conductive film 172b, and the conductive film 174b are reduced. While heating at a temperature of 00° C. or more and 400° C. or less, the conductive film 170b, the conductive film 172b, and the conductive film Next, the conductive film 170b, the conductive film 172b, and the conductive film 174b are exposed to silane. The conductive material is exposed 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 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. The step of adding the element 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, Then, as shown in FIG. 22(A), the mask 111 is removed. Remove.

[0346] Next, as shown in FIG. 22B, the oxide semiconductor film 166, the insulating film 168, the conductive film 17 1, an insulating film 176 is formed over the conductive film 172 and the conductive film 174, and then the conductive film 170 and the The oxide semiconductor film is 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 a conductive film 170, a conductive film 172, and a conductive film 174. Since there is no overlap, it is possible to reduce 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 transistors is reduced.

[0349] The structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiment modes. 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 a semiconductor device and a 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 dashed line X1-X2 in FIG. 23(A); 23A is a cross-sectional view taken along 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 has the same structure as the transistor 150 shown 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. 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 are provided with a conductive film. The film 124 contacts the insulating film 118 .

[0356] The insulating film 122 is made of a material such as polyimide, acrylic, polyamide, or epoxy. The insulating film 122 may be a resin film having 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 insulating film 11 can be formed using a light-transmitting conductive material such as indium tin oxide.

[0358] The conductive film 124 may be made of silver, aluminum, chromium, copper, tantalum, titanium, molybdenum, or the like. It can be formed by using a metal element that reflects light, such as rhodium or tungsten. Further, a film formed using a metal element that reflects light and a conductive material having the above-mentioned light-transmitting property are used. 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. For this reason, the oxide semiconductor film 156 has conductivity.

[0360] When the conductive film 124 is formed using a light-transmitting conductive material, 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 a 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 dashed line X1-X2 in FIG. 24(A); 24(A) is a cross-sectional view taken along 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 Numbers such as 182 are omitted.

[0363] The transistor 190 shown in FIG. 24 is the same as the transistor 190 shown 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. 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.

[0368] The oxide semiconductor film 198 is formed through the same process as the oxide semiconductor film 166. In addition, the impurity element is not contained in the oxide semiconductor film 166 like the region 166b. Therefore, the oxide semiconductor film 198 has conductivity.

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

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

[0371] The structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiment modes. They can be used in combination.

[0372] (Embodiment 4) 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, a possible structure of an oxide semiconductor film will be described below.

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

[0375] From another point of view, the oxide semiconductor is classified into an amorphous oxide semiconductor and a crystalline oxide semiconductor. Crystalline oxide semiconductors are classified into single crystal oxide semiconductors, CAAC- These include OS, polycrystalline oxide semiconductors, and microcrystalline oxide semiconductors.

[0376] <caac-os> First, let me explain about CAAC-OS. The oxide semiconductor has axially aligned nanocrystals. It is also possible.

[0377] CAAC-OS is an oxide that has 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, in high-resolution TEM images, the boundaries between pellets, i.e., grain boundaries, are clearly visible. Therefore, it is difficult to clearly confirm the presence of the CAAC-OS at the grain boundaries. It can be said that the decrease in electron mobility caused by the above phenomenon is unlikely to occur.

[0379] The following describes 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 corrector function was used. , specifically called a Cs-corrected high-resolution TEM image. Cs-corrected high-resolution TEM images are 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] A Cs-corrected high-resolution TEM image of the enlarged area (1) in Figure 34(A) is shown in Figure 34(B). From Figure 34(B), it can be confirmed 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 called 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 FIG. 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 inclination 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 inclination occurs corresponds to an area 5161 shown in FIG.

[0383] FIG. 35(A) shows the C 35(A) shows the s-corrected high-resolution TEM images of regions (1), (2) and (3) in FIG. ) are enlarged Cs-corrected high-resolution TEM images shown in Fig. 35(B), Fig. 35(C) and Fig. 35(D), respectively. As shown in Figure 35(D), from Figure 35(B), Figure 35(C) and Figure 35(D), 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 was analyzed by X-ray diffraction (XRD). We will explain AAC-OS. For example, CAAC-O with InGaZnO4 crystals When the out-of-plane structural analysis is performed on S, the result is 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 has a c-axis orientation. It can be seen that the crystal has a c-axis oriented in a direction substantially perpendicular to the surface on which the crystal is formed or to the upper surface.

[0385] In addition, in the out-of-plane structural analysis of CAAC-OS, 2θ is 31 In addition to the peaks 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 contains crystals that do not have the c-axis orientation. The more preferable CAAC-OS is a structure obtained by the out-of-plane method. The analysis shows a peak at 2θ around 31° and no peak at 2θ around 36°.

[0386] On the other hand, in-pla, X-rays are incident on CAAC-OS from a direction nearly perpendicular to the c-axis. When the structure is analyzed by the NE method, a peak appears at 2θ of about 56°. This peak is I It is attributed to the (110) plane of the crystal of nGaZnO4. In the case of CAAC-OS, 2θ is set to 5 The sample was 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 FIG. 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 the b-axis is irregular.

[0387] Next, we will explain the CAAC-OS analyzed by electron diffraction. For CAAC-OS with ZnO4 crystals, a probe diameter of 300 nm was used 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 InGaZnO4 The spots due to the (009) plane of the crystal are included. Therefore, even by electron diffraction, 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 perpendicular to the sample surface, The diffraction pattern when an electron beam with a diameter of 300 nm was incident is shown in FIG. 2(B) shows a ring-shaped diffraction pattern. Therefore, electron diffraction also It can be seen that the a-axis and b-axis of the pellets contained in CAAC-OS do not have any orientation. In addition, 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, etc.

[0388] In addition, the CAAC-OS is an oxide semiconductor with a low density of defect states. The 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 can 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 have a higher acidity than metal elements that constitute oxide semiconductors. Elements with strong bonds to oxygen 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, an oxide semiconductor with a low density of defect states (few oxygen vacancies) has a low carrier density. Such an oxide semiconductor can be a highly pure intrinsic or substantially highly pure intrinsic oxide semiconductor. CAAC-OS is called an oxide semiconductor. It 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 Also, it is rare for the product to be pure or substantially pure. Oxide semiconductors have few carrier traps. The charge that is stored in the material takes a long time to be released and behaves like a fixed charge. Therefore, a transistor using an oxide semiconductor with a high impurity concentration and a high density of defect states is required. On the other hand, transistors using CAAC-OS can have unstable electrical characteristics. The resulting transistor has small fluctuations in electrical characteristics and is highly reliable.

[0392] In addition, because the density of defect states in CAAC-OS is low, the defects generated by light irradiation can be easily removed. Therefore, the carriers are less likely to be captured by the defect states. The electrical characteristics of a transistor vary little 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 in which a crystal part is not clearly observed and a region in which a crystal part is not clearly observed. The crystal part contained is 1 nm to 100 nm or 1 nm to 10 nm in size. In particular, fine crystals with sizes between 1 nm and 10 nm or between 1 nm and 3 nm are often The oxide semiconductor with nanocrystals is called nc-OS (nanocrystallin The nc-OS is called NC-Oxide Semiconductor. In some cases, the grain boundaries cannot be clearly seen 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 is used in microscopic regions (e.g., regions between 1 nm and 10 nm, especially regions between 1 nm and The atomic arrangement has periodicity 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 that uses X-rays with a diameter larger than that of the pellet for nc-OS may be used. When the structure was analyzed using the out-of-plane method, the crystal plane was not 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 are used that use an electron beam with a probe diameter close to the size of the pellet or smaller than the pellet. When the nc-OS is folded, spots are observed. In some cases, a bright area with a circular (ring-like) appearance 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) The oxide semiconductor or NANC (Non-Aligned Nanocrystal The semiconductor may also be referred to as an oxide semiconductor having a structure including a metal oxide layer.

[0397] The nc-OS is an oxide semiconductor with higher order than an amorphous oxide semiconductor. However, the density of defect states in the nc-OS is lower than that in the amorphous oxide semiconductor. In the case of S, there is no regularity in the crystal orientation between different pellets. Therefore, the 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 in the film is irregular and there are no crystalline parts. An example is an oxide semiconductor that has an amorphous state, such as quartz.

[0400] In the case of an amorphous oxide semiconductor, no crystalline parts can be confirmed in a high-resolution TEM image.

[0401] When the structure of amorphous oxide semiconductors is analyzed using an XRD device, out-of-p In the lane analysis, no peaks indicating crystal planes were detected. When electron diffraction is performed on a conductor, a halo pattern is observed. When nanobeam electron diffraction was performed on the specimen, no spots were observed, only a halo pattern was 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. In addition, the distance between the nearest neighbors or the second nearest neighbors is called the structure. A structure that has order at the interface and no 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-crystalline oxide semiconductor. In addition, it cannot be called an crystalline oxide semiconductor. Amorphous oxide semiconductors cannot be called amorphous oxide semiconductors. For example, CAAC-OS and nc-OS can be 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 (alumina-like oxide semiconductor). ike OS:amorphous-like Oxide Semiconductor It is called r).

[0404] In a-like OS, voids are observed in high-resolution TEM images. In addition, crystals may be clearly visible in high-resolution TEM images. and regions where no crystalline portion can be confirmed.

[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 change in structure due to 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 obtained. It can be seen that all the materials have crystalline parts.

[0408] The determination of which part is 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 layered 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 between the crystals is 0.28 nm or more and 0.30 nm or less are considered to be crystal parts of InGaZnO4. The lattice fringes correspond to the ab plane of the InGaZnO4 crystal.

[0409] Figure 43 shows an example of the average size of the crystal parts (22 to 45 places) of each sample. However, the length of the lattice fringes is the size of the crystal part. It can be seen that the crystalline part of the ke OS grows in size according to the cumulative dose 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), which 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 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 crystals within the range of As shown in (2) and (3) in Fig. 43, 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] Thus, in a-like OS, the growth of crystals can be observed by electron irradiation. On the other hand, in the case of nc-OS and CAAC-OS, the growth of the crystals due to electron irradiation is almost nonexistent. In other words, a-like OS is not seen as a nc-OS or CAAC-OS. It is clear that it has an unstable structure compared to the OS.

[0411] In addition, because of the porosity, a-like OS is more difficult to treat than nc-OS and CAAC-OS. Specifically, the density of the a-like OS is The density of the nc-OS and the CAA 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 5.0g / 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 of the same composition do not exist. In such cases, crystals of different compositions may be used in any ratio. By combining single crystals of the desired composition, the density equivalent to that of a single crystal of the desired composition 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 weighted average of the proportion of It is preferable to estimate the size of the single crystal by combining different types of single crystals.

[0414] As described above, oxide semiconductors have various structures and each structure 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 having 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. 44A shows a process of forming a CAAC-OS film by a sputtering method. FIG. 1 is a schematic diagram of the inside of a membrane chamber.

[0417] The target 5130 is attached to a backing plate. A plurality of magnets are disposed at positions facing the target 5130 through the magnets. The magnetic field is generated by a number of magnets. The magnetic field of the magnets is used to increase the deposition speed. 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 (TS distance) is preferably 0.01 m or more and 1 m or less. The deposition chamber is mostly filled with deposition gas (e.g., oxygen, argon, or a mixture containing 5% or more by volume of oxygen) and The pressure is controlled to be 1 Pa or more and 100 Pa or less, preferably 0.1 Pa or more and 10 Pa or less. By applying a certain voltage to the target 5130, a discharge starts and a 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 ion 5101 is, for example, an oxygen cation (O + ) and argon cations ( Ar + ) etc.

[0419] Here, the target 5130 has a polycrystalline structure having multiple crystal grains, The crystal grains include cleavage planes. FIG. 45(A) shows an example of a crystal grain included in a target 5130. The crystal structure of InGaZnO4 is shown in Fig. 45(A). This is the structure of InGaZnO4 crystals observed from the outside. In the Ga-Zn-O layers, the oxygen atoms in each layer are arranged in close proximity. The negative charge of the oxygen atom causes the two adjacent Repulsion occurs between the Ga-Zn-O layers. As a result, the InGaZnO4 crystals are The cleavage plane is 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 generated from the cleavage plane. Pellet 5100a and pellet 5100b, which are pellet-shaped sputtered particles, are peeled off and struck. The pellets 5100a and 5100b are the same as the pellets 5101. The impact of a collision can cause distortion of the structure.

[0421] The pellet 5100a is a flat plate or pellet having a triangular, for example equilateral, 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 having a plate-like or pellet-like shape. The term pellets refers to flat or pellet-shaped sputter particles such as pellet 5100b. The planar shape of the pellet 5100 is not limited to a triangle or a hexagon, but may be any shape, e.g. For example, a shape may be formed by combining multiple triangles. In some cases, the shape may be a quadrilateral (for example, a rhombus) made up of two joined sides.

[0422] The thickness of the pellet 5100 is determined according to the type of deposition gas. The reason will be explained later. It is preferable that the thickness of the pellet 5100 is uniform. A pellet shape with no lumps is preferable to a thick cube shape. The thickness of the 5100 is 0.4 nm to 1 nm, preferably 0.6 nm to 0.8 nm. For example, the pellet 5100 has a width of 1 nm or more and 3 nm or less. The diameter of the pellet 5100 is 1.2 nm or more and 2.5 nm or less. For example, the target 5 having In-Ga-Zn oxide corresponds to the initial nucleus described in . When ions 5101 are bombarded with the Ga-Zn-O layer 130, as shown in FIG. A pellet 5100 having three layers, an In-O layer and a Ga-Zn-O layer, is peeled off. FIG. 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 (fixing). 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, for example, have negatively charged oxygen atoms located on its sides. The sides of the particles have the same polarity of charge, so the charges repel each other, forming a flat or pentamorphic 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 be possible that the pellet 5100 may be irradiated with the plasma. The area where the atoms grow by bonding with indium, gallium, zinc, and oxygen atoms. 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 Since the growth of 5100 does not occur easily, the OS becomes nc-OS (see Figure 44(B)). Since the film can be formed at a high speed, nc-OS can be formed even on a large substrate (5120). In order to grow the pellet 5100 in plasma, a sputtering method is used. It is effective to increase the film formation power in the pellet 5. 100 structures can be stabilized.

[0424] As shown in FIG. 44(A) and FIG. 44(B), for example, a 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 the 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. In addition, a vertical 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 electrodes 130, the electric field from the substrate 5120 to the target 5130 Therefore, the pellet 5100 is disposed on the upper surface of the substrate 5120 in the following manner: The magnetic field and the electric current act on the object, resulting in a force (Lorentz force). This is what Fleming This can be understood by the left-hand rule.

[0425] The pellet 5100 has a large mass compared to a single 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 the substrate 5120 must be 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. At the top surface of the plate 5120, a magnetic field parallel to the top surface of the substrate 5120 At least 1.5 times, preferably at least 2 times, more preferably at least 3 times the magnetic field perpendicular to the top surface. It is preferable to provide an area where the thickness is 5 times or more.

[0426] At this time, the magnet and the substrate 5120 move or rotate relatively. 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. 0 and the substrate 5120, the resistance due to friction 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 pellet 5100 reaches its side surface, the sides of the pellet 5100 are joined together. The oxygen atom on the side of 00 is removed. The removed oxygen atom causes the Since oxygen vacancies may be filled, the CAAC-OS has a low density of defect states. The temperature of the upper surface of the plate 5120 is, for example, 100° C. or more and less than 500° C., 150° C. or more and 450° C. The temperature may be set to 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 relieved. Pellet 5100 is almost single crystal. Even if the pellets 5100 are heated after being bonded to each other, the pellets 5100 themselves do not expand. Therefore, the gaps between the pellets 5100 widen, and the crystals 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 pellets are made of nano-crystals, and the aggregates resemble bricks or blocks stacked together. In addition, there are no grain boundaries between the pellets 5100. Heating during and after film formation, or bending, can cause deformation such as shrinkage in CAAC-OS. Even if the deformation occurs, it is possible to relieve the local stress or release the strain. This structure is suitable for use in flexible semiconductor devices. The result is an arrangement in which Ret 5100 (nanocrystals) are randomly stacked.

[0430] When the target 5130 is sputtered by ions 5101, not only the pellet 5100 but also Zinc oxide may peel off. 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. A schematic cross-sectional view is shown in Figure 46.

[0431] As shown in FIG. 46(A), a pellet 5105a and a pellet Here, the pellets 5105a and 5105b are piled up. The pellets 5105c and 5105c are arranged so that their sides are in contact with each other. After being deposited on the pellet 5105b, the pellet 510 slides on the pellet 5105b. In another aspect of FIG. 05a, 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 condensing the pellet 5105a2. 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 pellet 5105b. It also slides toward the other side of the pellet 5105c. The pellet 5105 e 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 is in contact with 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 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 that occurred after deposition.

[0436] In addition, the gaps between the pellets become extremely small, so that one large pellet is formed. One large pellet may have a single crystal structure. For example, The size is 10 nm or more and 200 nm or less, 15 nm or more and 100 nm or less, as viewed from the top. In some cases, the size of the transistors used is between 20nm and 50nm. In an oxide semiconductor, a channel formation region may be contained within one large pellet. That is, a region having a single crystal structure can be used as a channel forming region. As the gap grows, 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 considered that the pellet 5100 is deposited on the substrate 5120. CAAC-OS can be deposited even on a surface that 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 achieve uniform growth even on large glass substrates. For example, 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 CAAC-OS is to be formed is uneven, 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 pellet 5100 has a uniform thickness, it is flat and has a uniform thickness. A layer with high crystallinity is formed. Then, the layer is stacked in n steps (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 unevenness, 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. Since the surface of the pellet 5100 is uneven, gaps tend to form between the pellets 5100 in the CAAC-OS. However, even in this case, intermolecular forces act between the pellets 5100, causing unevenness. Even if the pellets are arranged in a way that the gaps between them are as small as possible. It is possible to obtain a CAAC-OS having high crystallinity.

[0441] Since the CAAC-OS film is formed by such a model, the sputtered particles are distributed evenly throughout the film. It is preferable that the sputtered particles are in the form of thick pellets. 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 shows that a highly crystalline film can be formed even on a substrate surface having an amorphous structure. Thus, a CAAC-OS having the above properties can be obtained.

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

[0444] The structures and methods described in this embodiment mode may be appropriately combined with the structures and methods described in other embodiment modes. 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 the above configuration will be described below with reference to FIGS.

[0446] FIG. 27A is a top view showing an example of a display device. 0 is a pixel portion 702 provided on a first substrate 701 and a A source driver circuit portion 704 and a gate driver circuit portion 706, a pixel portion 702, a source A seal disposed to surround the driver circuit section 704 and the gate driver circuit section 706. The semiconductor device has a first substrate 712 and a second substrate 705 disposed opposite the first substrate 701. The first substrate 701 and the second substrate 705 are sealed with a sealant 712. That is, a pixel section 702, a source driver circuit section 704, and a 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, a gap between the first substrate 701 and the second substrate 705 A display element is provided on the display panel.

[0447] The display device 700 is surrounded by a sealant 712 on the first substrate 701. A pixel section 702, a source driver circuit section 704, and a gate driver circuit section 705 are arranged in a region different from the region. The flexible printed circuit (FPC) terminal section 708 is electrically connected to the flexible printed circuit (FPC) circuit section 706. In addition, the FPC terminal portion 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 switch portion 703, and the gate driver circuit portion 706. The base driver circuit section 704, the gate driver circuit section 706, and the FPC terminal section 708 are Various signals supplied by the FPC 716 are A pixel section 702, a source driver circuit section 704, a gate driver circuit section 705, and a portion 706, and an FPC terminal portion 708.

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

[0449] Furthermore, the display devices 700 and 800 may each include a plurality of gate driver circuits 706. In addition, the display devices 700 and 800 include a source driver circuit section 704 and a gate driver In this example, 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, only the gate driver circuit section 706 may be 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 circuits and the like are formed (for example, a driving circuit formed of a single crystal semiconductor film or a polycrystalline semiconductor film) A configuration in which a first substrate (a circuit board) is mounted on the first substrate 701 may be used.

[0450] The method of connecting the separately formed drive circuit board is not particularly limited, and may be any method such as COG. Chip On Glass method, wire bonding method, etc. can be used. In this specification, the 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 attached to the end of the TCP. The module or display element is fitted with a drive circuit board or IC ( The display device also includes all modules on which a display device (integrated circuit) is directly mounted.

[0451] In addition, the pixel units 702 and 802 and the source driver circuit units The gate driver circuit section 704 and the gate driver circuit section 706 have a plurality of transistors. A transistor which is a semiconductor device of one embodiment can be used.

[0452] The display device 700 uses liquid crystal elements as display elements, 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 A light-emitting device, which is a device for displaying light, can have various forms or elements. The display element, the display device, the light-emitting element, or the light-emitting device is, for example, an EL (electroluminescent EL 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 emitted from a light source), electron emission elements, liquid crystal elements, electronic ink, electrophoretic elements, Grating light valve (GLV), plasma display (PDP), MEMS ( Display elements using microelectromechanical systems, digital microcomputers 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 optical interference method, electrowetting element display elements using carbon nanotubes, piezoelectric ceramic displays, etc. In addition to these, contrast can also be achieved by electrical or magnetic effects. The display medium may have a variable brightness, reflectance, transmittance, etc. An example of a display device is an EL display. One example is a field emission display (FED) or SED type flat panel display. Display (SED: Surface-conduction Electron-e Examples of display devices using liquid crystal elements include the LCD (Light Emitting Diode) and the LCD (Light Emitting Diode). , LCD (transmissive LCD, semi-transmissive LCD, reflective LCD) LCDs include LCDs, direct-view LCDs, and projection LCDs. An example of a display device using ink or electrophoretic elements is electronic paper. In order to realize a semi-transmissive liquid crystal display or a reflective liquid crystal display, the pixel electrodes A part or the whole of the pixel may function as a reflective electrode. A part or the whole 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 under the reflective electrode. This makes it possible to further reduce power consumption.

[0454] First, the common parts of the display device 700 and the display device 800 will be described, and then the differences will be described. The display device 700 and the display device 800 will be described in detail with reference to FIGS. 28 and 29. He explains.

[0455] <Explanation of common parts of display device> 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 cut surface taken along the dashed line VW shown in FIG. 27(B). .

[0456] The display devices 700 and 800 shown in FIGS. 28 and 29 each 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. The conductive film is formed in the same process as the gate electrode, the source electrode, and the 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 a source electrode layer and a 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 anisotropic conductive film 716 is electrically connected to the terminal of the anisotropic conductive film 780 .

[0459] In the display devices 700 and 800 shown in FIGS. 28 and 29, pixel units 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 provided as an example. The transistor 750 and the transistor 760 have the same structure as 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 having the configuration shown in FIG. 19 is used. That's fine.

[0460] The transistor used in this embodiment is made of a highly purified oxide film in which the formation of oxygen vacancies is suppressed. By using the semiconductor film, the current value in the off state (off current value) can be reduced. This allows the retention time of electrical signals such as image signals to be extended, and writing is possible while 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 to suppress the formation of oxygen vacancies. Since the device has an oxide semiconductor film and has a relatively high field-effect mobility, it can be driven at high speed. For example, by using such a transistor capable of high speed operation 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 is possible to form the driver circuit on a single substrate, such as a silicon wafer. Since it is not necessary to use a semiconductor device formed by a method for manufacturing a semiconductor device, the number of components of the semiconductor device can be reduced. In addition, by using a transistor capable of high speed operation in the pixel portion, It is possible to provide high quality images.

[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 wire. This 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 appropriate. 28 and 29, the gate driver circuit section 706 can Although not shown, it can have the same configuration as the source driver circuit portion 704 .

[0464] In addition, in FIG. 28 and FIG. 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 are the insulating films 116 and 118 shown in the previous embodiment and the insulating films 764 and 766 are the same as those shown in the previous embodiment. They can be formed from similar materials and by similar manufacturing methods.

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

[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 is formed on the planarization insulating film 770, which functions as one electrode of the display element. The conductive film 772 is preferably a conductive film that transmits visible light. The conductive film is made of, for example, indium (In), zinc (Zn), or tin (Sn). In addition, the conductive film 844 may be a conductive film having a reflectivity. 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 a 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. By controlling the light transmission or non-transmission, an image can be displayed.

[0469] Although not shown in FIG. 28, the conductive films 772 and 774 on the side in contact with the liquid crystal layer 776 An alignment film may be provided on each of the electrodes. 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 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. An example of the flexible substrate is a plastic substrate.

[0471] In addition, a spacer 778 is provided between the first substrate 701 and the second substrate 705 . The spacer 778 is a columnar spacer obtained by selectively etching an insulating film. The spacer 776 is provided to control the 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 crystal, low molecular weight liquid crystal, high molecular weight liquid crystal, Liquid crystals, polymer-dispersed liquid crystals, ferroelectric liquid crystals, antiferroelectric liquid crystals, etc. can be used. Depending on the conditions, the liquid crystal material can have 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, 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. When the temperature of a cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the black phase to the isotropic phase. 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 the 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 liquid crystal and a chiral agent, the viewing angle dependency can be reduced. In addition, when a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent is used, an alignment film can be provided. Since it is not necessary to apply a rubbing treatment, the damage caused by the rubbing treatment is eliminated. It is possible to prevent electrostatic damage 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] In addition, when liquid crystal elements are used as display elements, 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 Electrochemical Liquid Crystal (ECC) mode can be used. .

[0475] In addition, normally black type liquid crystal display devices, for example, those using a vertical alignment (VA) mode The liquid crystal display device may be a transmission type liquid crystal display device. There are several types of vertical alignment modes, including: 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, etc. In addition, the color elements controlled by pixels when displaying colors are RG B (R stands for red, G stands for green, B stands for blue) are not limited to the three colors. For example, It may be composed of four pixels: a blue pixel, a blue pixel, and a white pixel. Or, it may be arranged in a Pentile array. As shown above, two colors of RGB are used to make one color element, and two different colors are created by using the color element. Alternatively, you can add one or more colors such as yellow, cyan, or magenta 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, and may be used for monochrome display devices. The present invention can also be applied to display devices such as those shown in FIG.

[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] In addition, in the display device 800 shown in FIG. 29, a planarization insulating film 770 and a conductive film 844 are An insulating film 830 is provided. The insulating film 830 covers a part of the conductive film 844. The conductive film 848 has a light-transmitting property. It transmits light emitted by the EL layer 846. In this embodiment, the top emission For example, a light emitting structure for emitting light to the conductive film 844 side is shown. A bottom emission structure in which light is emitted to both the conductive film 844 and the conductive film 848 is also available. 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 at the position where the light-shielding film 838 is to be formed, 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. The space between the insulating film 834 and the insulating film 834 is filled with a sealing film 832. In the above embodiment, the colored film 836 is provided, but 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. 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. It is provided on the planarization insulating film 770 on the first electrode 710 and functions as a reflective electrode. The display device 700A uses 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, for example, by forming the planarization insulating film 770 with an organic resin film or the like. The reflecting surface can be formed by forming the organic resin film with unevenness. The conductive film 773 functioning as an electrode is formed along the unevenness. When light enters the conductive film 773, it can be diffusely reflected on the surface of the conductive film 773. As a result, visibility can be improved.

[0483] In addition, the display device 700A 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. The display device 70 can be formed by using the materials and methods described in the above. The conductive film 773 in FIG. 1 functions as a source electrode or a drain electrode of the transistor 750. The conductive film 773 is electrically connected to the 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 includes a pair of electrodes More specifically, the capacitor 790 is a gate of the transistor 750. A conductive film formed in the same process as a conductive film functioning as an electrode, a source electrode, and a drain electrode as one electrode, and the conductive film that functions as a wiring of the transistor 750 A conductive film 792 formed in one step is used as the other electrode, and an insulating film is provided 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 connecting electrode 760 instead of a The signal line 710a, the connection electrode 760a, and the conductive film 79 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 which is a semiconductor device of one embodiment of the present invention includes a conductive film which 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. The conductive film that functions as the gate electrode is formed on the same plane. Either or both of the conductive films functioning as a source electrode and a drain electrode may be formed of a different material. 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 An example of a connection portion for connecting the conductive films will be described with reference to FIG.

[0488] FIG. 37(A) is a top view of the connection portion 900, and FIG. 37(B) is a cross-sectional view of a portion of FIG. 37(A). 37B is a cross-sectional view taken along dashed line Z1-Z2. Note that, 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, Conductive films 910, 912, and 914 on the insulating film 908; 12, an insulating film 916 on 914, 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 through 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 the embodiment mode 1. The insulating films 904, 908, and 916 are the same as the insulating film 104 shown in Embodiment 1. The conductive films 910, 912, and 916 may be made of the same material. The conductive films 14 and 945 are made of the same material as the conductive films 110, 112, and 114 described in the first embodiment. can be used.

[0491] The conductive film 910 may be a conductive 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 connection portion for connecting conductive films will be described with reference to FIG.

[0493] FIG. 40(A) is a top view of the connection portion 900, and FIG. 40(B) is a cross-sectional view of a portion of FIG. 40(A). 40B is a cross-sectional view taken along dashed line Z1-Z2. Note that, 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 to each other 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 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 according to 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. 31A 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. This is also 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 the whole 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 Band). It can be implemented by using the onding.

[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, a gate driver) that outputs a signal (scanning signal) for selecting a pixel. 504a) to provide a signal (data signal) for driving the display element of the pixel. The pixel circuit 504 includes a driver circuit such as a 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 input via a terminal unit 507, and a signal is output. For example, a start pulse signal, a clock signal, etc. are input to the gate driver 504a. The gate driver 504a 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 scanning lines GL_1 to Alternatively, the gate driver 504a may control the GL_X by dividing it. However, the gate driver 50 has a function of supplying 4a may also provide another signal.

[0502] The source driver 504b includes a shift register and the like. Through the terminal section 507, a signal for driving the shift register as well as a source of a data signal are input. The source driver 504b receives a signal (image signal) that is to be displayed on the pixel circuit based on the image signal. The source driver 504b has a function of generating a data signal to be written to the pixel 501. A data signal is generated according to 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 same wiring. Alternatively, the source driver 504b may have a function of supplying 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 number of analog switches, The image signal can be time-division-divided and output as a data signal. Also, a shift register, etc. This may be used to configure the source driver 504b.

[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 through the line DL, and a data signal is provided through 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 smaller 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 a line (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 unit 507. Alternatively, the protection circuit 506 may be a wiring between the source driver 504b and the terminal unit 507. The terminal unit 507 can be connected to the display device from an external circuit. This refers to the part provided with terminals for inputting control signals and image signals.

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

[0507] As shown in FIG. 31A, 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 overcurrent caused by electrostatic discharge (ESD) 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 protection circuit 506 is connected to the source driver 504b Alternatively, a protection circuit 506 may be connected to the terminal portion 507. It can also be written as:

[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 source driver circuit is formed separately. A substrate (for example, a drive circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is It may also be configured to be equipped with

[0509] In addition, the pixel circuits 501 shown in FIG. 31(A) may have a configuration shown in FIG. 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 150 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 appropriately set according to the specifications of the pixel circuit 501. The alignment 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 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. A different potential may be applied to one of the electrodes.

[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 M icro-cell mode, OCB (Optically Compensated Birefringence mode, FLC (Ferroelectric Liquid 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, etc. may also be used. In addition to the above-mentioned driving method, the display device can be driven by an ECB (Electric Carrier Bipolar Transistor) or the like. Ally Controlled Birefringence mode, PDLC(P Oligomeric Dispersed Liquid Crystal (PNLC) mode (Polymer Network Liquid Crystal) mode, guest hole However, there are various types of liquid crystal elements and their driving methods, and they are not limited to these. A variety of different types of sensors can be used.

[0514] In the pixel circuit 501 in the mth row and the nth column, 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 scanning lines GL _m. The transistor 550 is electrically connected to the on-state or the off-state. This has the function of controlling the writing of data of the data signal.

[0515] One of a 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 shown in FIG. The pixel circuits 501 in each row are sequentially selected by a gate driver 504a shown in FIG. 550 is turned on to write data of the data signal.

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

[0518] In addition, the pixel circuits 501 shown in FIG. 31(A) may have a configuration shown in FIG. It can be said that:

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

[0520] A data signal is applied to one of the source and drain electrodes of the transistor 552. 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 a 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 storing 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. In addition, the gate electrode of the 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 the cathode of the light-emitting element 572 is electrically connected to the potential supply line VL_b. The other one 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 called 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 shown in FIG. 31C, 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] In the pixel circuit 501 to which the data has been written, the transistor 552 is turned off. Furthermore, the transistor 554 is 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 with a brightness that corresponds to the flow rate. By performing this process row by row, an image can be displayed.

[0530] The structure described in this embodiment 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 The electronic device will be described with reference to FIGS. 32 and 33. FIG.

[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, A display panel 8006, a backlight 8007, a frame 8009, and a 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 appropriate to match the size of 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 the display panel 006 to make it into an optical touch panel.

[0536] The backlight 8007 has a light source 8008. In FIG. In the above embodiment, the light source 8008 is disposed on the light source 8007, but 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 need not be provided.

[0537] The frame 8009 protects the display panel 8006 and also supports 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 frame. 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 be added.

[0540] 33(A) to 33(H) are diagrams showing electronic devices. These electronic devices are A body 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, and an 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 in addition to the above includes a switch 5009 , an infrared port 5010, etc. FIG. 33(B) shows a mobile phone equipped with a recording medium. A portable image reproducing device (e.g., a DVD reproducing device) and, in addition to the above, the following devices are also included: The display unit 5002, the recording medium reading unit 5011, etc. In addition to the above, the display includes a second display unit 5002 and a support unit 5012. , earphones 5013, etc. FIG. 33(D) shows a portable game machine. In addition to the above, the recording medium reading unit 5011 and the like can be included. This is a digital camera with a television 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. This is a slot 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, The portable television receiver may include a tuner, an image processor, etc. In addition to the above, the device includes a charger 5017 capable of transmitting and receiving signals. can be done.

[0542] The electronic devices shown in FIGS. 33(A) to 33(H) can have various functions. For example, the function to display various information (still images, videos, text images, etc.) on the display, Panel function, calendar, date or time display function, various software (platform A function to control processing by a program, a wireless communication function, and a function to control various Functions for connecting to computer networks, wireless communication functions for transmitting various data, 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 the other display section is used mainly to display text information. A function to display images with parallax taken into account on multiple displays to create a stereoscopic effect. Furthermore, in electronic devices having an image receiving unit, These include functions for taking still images, taking videos, and automatically or manually correcting the images. The camera has a function to correct the captured image, a function to save the captured image on a recording medium (external or built-in to the camera), The image displayed on the display unit can have a function of displaying the image. The functions that the electronic device shown in 3(H) can have are not limited to these, and various functions may be included. It is possible to 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 having a display portion. can also be applied to

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

[0545] 102 Substrate 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 Transistor 152 Transistor 153 Transistor 154 Transistor 156 Oxide Semiconductor Film 159 Capacitive element 162 Substrate 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 Transistor 192 Transistors 193 Transistor 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 Transistor 552 Transistor 554 Transistor 560 Capacitive element 562 Capacitive element 570 Liquid crystal element 572 Light emitting element 700 Display device 700A display device 701 Substrate 702 Pixel section 704 Source driver circuit section 705 Substrate 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 Transistor 760 Connection electrode 760a Connection electrode 764 Insulating film 766 Insulating Film 770 Planarizing 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 Capacitive element 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 Substrate 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 cabinet 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 Pellet 5100b Pellets 5101 AEON 5102 Zinc oxide layer 5103 particles 5105a Pellet 5105a1 area 5105a2 Pellet 5105b Pellet 5105c Pellet 5105d Pellet 5105d1 area 5105e Pellet 5120 Circuit 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 liquid crystal display device having a plurality of pixels, a display device including a transistor and a capacitor electrically connected to the 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; a first oxide semiconductor film having a region in contact with an upper surface of the first insulating film and having a channel formation region of the transistor; a second conductive film having a region in contact with a top surface of the first 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 first 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 first oxide semiconductor film; a fourth conductive film having a region overlapping with the first oxide semiconductor film with the second insulating film interposed therebetween and functioning as a second gate electrode of the transistor; 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 first oxide semiconductor film; a fifth conductive film having a region in contact with the second conductive film through an opening in the third insulating film and functioning as a pixel electrode; a sixth 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 seventh conductive film having a region in contact with an upper surface of the sixth conductive film and a region in contact with a lower surface of the third insulating film; a second oxide semiconductor film having a region in contact with an upper surface of the first insulating film and functioning as an electrode of the capacitor; the third conductive film is electrically connected to the seventh conductive film via the sixth conductive film; the second conductive film, the third conductive film, the fourth conductive film, and the seventh conductive film have the same material; The display device, wherein the first oxide semiconductor film is made of the same material as the second oxide semiconductor film.

2. A liquid crystal display device having a plurality of pixels, a display device including a transistor and a capacitor electrically connected to the 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; a first oxide semiconductor film having a region in contact with an upper surface of the first insulating film and having a channel formation region of the transistor; a second conductive film having a region in contact with a top surface of the first 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 first 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 first oxide semiconductor film; a fourth conductive film having a region overlapping with the first oxide semiconductor film with the second insulating film interposed therebetween and functioning as a second gate electrode of the transistor; 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 first oxide semiconductor film; a fifth conductive film having a region in contact with the second conductive film through an opening in the third insulating film and functioning as a pixel electrode; a sixth 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 seventh conductive film having a region in contact with an upper surface of the sixth conductive film and a region in contact with a lower surface of the third insulating film; a second oxide semiconductor film having a region in contact with an upper surface of the first insulating film and functioning as an electrode of the capacitor; the third conductive film is electrically connected to the seventh conductive film via the sixth conductive film; the second conductive film, the third conductive film, the fourth conductive film, and the seventh conductive film have the same material; the first oxide semiconductor film has a same material as the second oxide semiconductor film; the first insulating film has a laminated structure of a first film having nitrogen and silicon and a second film located on the first film and having oxygen and silicon; the second insulating film includes oxygen and silicon; The display device, wherein the third insulating film contains oxygen and silicon.

3. A pixel having a plurality of pixels, a display device including a transistor and a capacitor electrically connected to the 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; a first oxide semiconductor film having a region in contact with an upper surface of the first insulating film and having a channel formation region of the transistor; a second conductive film having a region in contact with a top surface of the first 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 first 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 first oxide semiconductor film; a fourth conductive film having a region overlapping with the first oxide semiconductor film with the second insulating film interposed therebetween and functioning as a second gate electrode of the transistor; 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 first oxide semiconductor film; a fifth conductive film having a region in contact with the second conductive film through an opening in the third insulating film and functioning as a pixel electrode; a sixth 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 seventh conductive film having a region in contact with an upper surface of the sixth conductive film and a region in contact with a lower surface of the third insulating film; a second oxide semiconductor film having a region in contact with an upper surface of the first insulating film and functioning as an electrode of the capacitor; the third conductive film is electrically connected to the seventh conductive film via the sixth conductive film; the second conductive film, the third conductive film, the fourth conductive film, and the seventh conductive film have the same material; the first oxide semiconductor film has a same material as the second oxide semiconductor film; the first oxide semiconductor film has a first region overlapping with the fourth conductive film via the second insulating film, a second region in contact with the second insulating film and not overlapping with the fourth conductive film, and a third region in contact with the third insulating film; the first region has a resistivity different from a resistivity of the second region; the first region has a resistivity different from a resistivity of the third region; the first insulating film has a laminated structure of a first film having nitrogen and silicon and a second film located on the first film and having oxygen and silicon; the second insulating film includes oxygen and silicon; The display device, wherein the third insulating film contains oxygen and silicon.

4. In claim 3, the second oxide semiconductor film has a resistivity different from a resistivity of the first region and a resistivity different from a resistivity of the second region.

5. In any one of claims 1 to 4, each of the second insulating film and the third insulating film has a single layer structure or a multilayer structure; the second conductive film and the third conductive film have a single layer structure or a stacked layer structure, The display device, wherein the first oxide semiconductor film and the second oxide semiconductor film have a single-layer structure or a stacked-layer structure.

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