Transistor

Abstract

To provide a novel material.SOLUTION: A composite oxide semiconductor comprises a first region and a plurality of second regions which are mixed therein. The first region contains at least indium, an element M (the element M is at least one of Al, Ga, Y and Sn) and zinc, and the second region contains indium and zinc. The indium is present in the second region at a higher concentration in comparison to that in the first region and therefore, the second region has a conductivity higher than that of the first region. An end of one of the plurality of second regions overlaps with another end of the plurality of second regions, and the first region envelopes the plurality of second regions sterically.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine , a manufacture, or a composition of matter. In particular , one aspect of the present invention relates to an oxide semiconductor or a method for manufacturing the oxide semiconductor. Also , one aspect of the present invention relates to a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a power storage device, a memory device, a driving method thereof, or a manufacturing method thereof.

[0002] Note that, in this specification and the like, the semiconductor device refers to all devices that can function by utilizing semiconductor characteristics. Semiconductor elements such as transistors, semiconductor circuits, arithmetic units, and memory devices are one aspect of semiconductor devices. Imaging devices, display devices, liquid crystal display devices, light-emitting devices, electro-optical devices, power generation devices (including thin-film solar cells, organic thin-film solar cells, etc.), and electronic devices may have a semiconductor device.

Background Art

[0003] In Non-Patent Document 1, it is described that a homologous phase represented by In 1-x Ga 1+x O3(ZnO) m (where x is a number satisfying -1 ≦ x ≦ 1 and m is a natural number) exists. Also , Non-Patent Document 1 describes the solid solution range of the homologous phase. For example, it is described that the solid solution range of the homologous phase when m = 1 is in the range where x is from -0 .33 to 0.08, and it is described that the solid solution range of the homologous phase when m = 2 is in the range where x is from -0.68 to 0.32. .33 to 0.08, and it is described that the solid solution range of the homologous phase when m = 2 is in the range where x is from -0.68 to 0.32.

[0004] Also, a technique for fabricating a transistor using an In-Ga-Zn-based oxide semiconductor has been disclosed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Non-Patent Document 1, examples of In x Zn y Ga z O w are shown, and when x, y, and z are compositions near ZnGa 2O4, that is, when x, y, and z have values close to (x, y, z) = (0, 1, 2) it is described that a spinel-type crystal structure is likely to form or coexist. As a compound having a spinel-type crystal structure, a compound represented by AB2O4 (A and B are metals) is known. However, when a spinel-type crystal structure forms in an In-Ga-Zn-based oxide semiconductor

[0008] or If they are mixed, it may have an adverse effect on the electrical characteristics or reliability of a semiconductor device (e.g., a transistor) having the In-Ga-Zn-based oxide semiconductor.

[0009] In view of the above problems, one aspect of the present invention is to provide a novel oxide semiconductor as one of the problems. Or, one aspect of the present invention is to impart good electrical characteristics to a semiconductor device as one of the problems. Or, one aspect of the present invention is to provide a highly reliable semiconductor device as one of the problems. Or, One aspect of the present invention is to provide a semiconductor device having a novel configuration as one of the problems. Or, one aspect of the present invention is to provide a display device having a novel configuration as one of the problems.

[0010] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not need to solve all of these problems. Note that other problems will be naturally apparent from the description of the specification, drawings, claims, etc., and it is possible to extract these other problems from the description of the specification, drawings, claims, etc.

Means for Solving the Problems

[0011] One aspect of the present invention is a composite oxide semiconductor in which a first region and a plurality of second regions are mixed. In the first region, it contains at least indium, element M (element M is any one or more of Al, Ga, Y, or Sn), and zinc. The second region contains indium and zinc. The indium in the second region is present at a higher concentration than in the first region. The second region has higher conductivity than the first region. One end of a plurality of second regions and the other end of a plurality of second regions overlap. The first region three-dimensionally surrounds the plurality of second regions. ​

[0012] In the composite oxide semiconductor having the above structure, the atomic ratio of indium, element M, and zinc is In:M :Zn = 5:1:6, or a value in the vicinity thereof.

[0013] In the first region having the above structure, the atomic ratio of indium, element M, and zinc is In:M: Zn = 4:2:3, or a value in the vicinity thereof.

[0014] In the second region having the above structure, the atomic ratio of indium, element M, and zinc is In:M: Zn = 2:0:3, or a value in the vicinity thereof.

[0015] In the composite oxide semiconductor having the above structure, the atomic ratio of indium, element M, and zinc is In:M :Zn = 4:2:3, or a value in the vicinity thereof.

[0016] In the first region having the above structure, the atomic ratio of indium, element M, and zinc is In:M: Zn = 1:1:1, or a value in the vicinity thereof.

[0017] In the second region having the above structure, the atomic ratio of indium, element M, and zinc is In:M: Zn = 2:0:1, or a value in the vicinity thereof.

[0018] The thickness of the second region having the above structure in the c-axis direction is 0.1 nm or more and less than 1 nm.

[0019] The first region having the above structure is non-single crystal.

[0020] The first region having the above structure includes a crystal part, and the c-axis of the crystal part has a portion parallel to the normal vector of the surface on which the composite oxide semiconductor film is formed. of the normal vector.

[0021] The second region having the above structure is non-single crystal.

[0022] Also, another aspect of the present invention is a transistor characterized by having a composite oxide semiconductor having the above configuration.

[0023] Also, another aspect of the present invention is a display device having any one of the above oxide semiconductors and a display element. Also, another aspect of the present invention is a display module having the display device and a touch sensor. Also, another aspect of the present invention is an electronic device having any one of the above oxide semiconductors, the above semiconductor device, the above display device, or the above display module and an operation key or a battery.

Advantages of the Invention

[0024] According to one aspect of the present invention, a novel oxide semiconductor can be provided. Or, according to one aspect of the present invention, good electrical characteristics can be imparted to a semiconductor device. Or, a highly reliable semiconductor device can be provided. Or, a semiconductor device having a novel configuration can be provided. Or, a display device having a novel configuration can be provided.

[0025] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that other effects will be apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0026]

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Mode for Carrying Out the Invention

[0027] Hereinafter, embodiments will be described with reference to the drawings. However, there are many different embodiments It can be implemented in the described manner, and it is easily understood by those skilled in the art that the form and details can be variously changed without departing from the spirit and scope thereof. Therefore, the present invention is not construed as being limited to the description of the following embodiments.

[0028] In addition, in the drawings, there are cases where the size, layer thickness, or area is exaggerated for clarity. Therefore, it is not necessarily limited to that scale. The drawings are schematic illustrations of ideal examples and are not limited to the shapes or values shown in the drawings.

[0029] In addition, it should be noted that the ordinal numbers "first", "second", "third", etc. used in this specification are attached to avoid confusion of components and are not numerically limiting.

[0030] In addition, in this specification, terms indicating arrangements such as "above" and "below" are used for convenience to explain the positional relationship between components with reference to the drawings. Also, the positional relationship between components appropriately changes according to the direction in which each component is depicted. Therefore, it is not limited to the terms described in the specification and can be appropriately rephrased according to the situation.

[0031] In addition, in this specification and the like, a transistor is an element having at least three terminals including a gate, a drain, and a source. And there is a channel region between the drain (drain terminal, drain region, or drain electrode) and the source (source terminal, source region, or source electrode), and a current can flow between the source and the drain through the channel region. Note that in this specification and the like, the channel region refers to the region through which current mainly flows. ​

[0032] In addition, the source and drain functions may differ depending on whether transistors with different polarities are used or the circuit operation. In some cases, such as when the direction of the current changes during operation, the positions may be reversed. In the text, the terms source and drain may be used interchangeably. .

[0033] In addition, in this specification, "electrically connected" means "something that has some electrical effect" " includes cases where the device is connected via "anything that has some electrical effect." " is not subject to any particular restriction as long as it enables the transmission and reception of electrical signals between the connection objects. For example, "things that have some kind of electrical function" include electrodes, wiring, and transistors. These include switching elements, resistor elements, inductors, capacitors, and other various functions. This includes elements such as

[0034] In this specification and the like, a silicon oxynitride film is a film having a composition containing more oxygen than nitrogen. A silicon nitride oxide film is a film that contains more nitrogen than oxygen. This refers to a film with a high content.

[0035] In addition, in this specification and the like, when explaining the configuration of the invention using drawings, the same The reference symbols may be commonly used even among different drawings.

[0036] In addition, in this specification, "parallel" means that two straight lines are at an angle of -10° or more and 10° or less. Therefore, it includes the case where the angle is between -5° and 5°. "Approximately parallel" refers to a state in which two straight lines are arranged at an angle of -30° or more and 30° or less. That is. Also, "vertical" means a state where two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, the case of 85° or more and 95° or less is also included. Also, "substantially vertical" means a state where two straight lines are arranged at an angle of 60° or more and 120° or less.

[0037] In addition, in this specification and the like, the term "film" and the term "layer" may, in some cases, be interchangeable with each other. For example, the term "conductive layer" may be changed to the term "conductive film" in some cases. Or, for example, the term "insulating film" may be changed to the term "insulating layer" in some cases.

[0038] Note that even when expressed as "semiconductor", for example, when the conductivity is sufficiently low, it may have the characteristics of an "insulator". Also, the boundary between "semiconductor" and "insulator" is ambiguous and may not be strictly distinguishable. Therefore, the "semiconductor" described in this specification may be paraphrased as "insulator" in some cases. Similarly, the "insulator" described in this specification may be paraphrased as "semiconductor" in some cases.

[0039] (Embodiment 1) In this embodiment, an oxide semiconductor which is one aspect of the present invention will be described.

[0040] The oxide semiconductor preferably contains at least indium. In particular, it preferably contains indium and zinc. In addition to these, it is preferable that aluminum, gallium, yttrium or tin, etc. are contained. Also, boron, silicon, titanium, iron nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium ​​, one or more selected from hafnium, tantalum, tungsten, magnesium, etc. may be included. Or multiple types may be included.

[0041] Here, consider the case where the oxide semiconductor has indium, element M, and zinc. Note that element M is aluminum, gallium, yttrium, tin, etc. Other elements applicable to element M include boron, silicon, titanium, iron, nickel, germanium , zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. However, as element M, there may be cases where a plurality of the aforementioned elements are combined. Note that the respective terms of the atomic ratios of indium, element M, and zinc in the oxide semiconductor are denoted as [In], [M], and [Zn].

[0042] <Structure of Oxide Semiconductor> Conceptual diagrams of the oxide semiconductor in the present invention are shown in FIGS. 1 to 4.

[0043] Conceptual diagrams of the oxide semiconductor of the present invention are shown in FIGS. 1 to 4. Note that FIGS. 1(A), 2(A), 3(A), and 4(A) are conceptual diagrams of the upper surface of the oxide semiconductor (herein referred to as the a-b plane direction), and FIGS. 1(B), 2(B), 3(B), and 4(B) are conceptual diagrams of a cross section (herein referred to as the c-axis direction) in which the oxide semiconductor is formed on the substrate Sub . . It is a conceptual diagram of the cross section (herein referred to as the c-axis direction) in which the oxide semiconductor is formed on the substrate Sub.

[0044] Note that in FIGS. 1 to 4, the case where the oxide semiconductor is formed on the substrate is illustrated However, it is not limited thereto, and an insulating film such as an underlayer film or an interlayer film , or another semiconductor film such as an oxide semiconductor may be formed between the substrate and the oxide semiconductor.

[0045] As shown in FIGS. 1(A) and 1(B), the oxide semiconductor of the present invention is a composite oxide semiconductor having a structure in which region A1 and region B1 are mixed. Region A1 is a region rich in In where [In]:[M]:[Zn]=x:y:z (x>0, y≧0, z≧0). On the other hand, region B1 is a region poor in In where [In]:[M]:[Zn]=a:b:c (a>0, b>0, c >0).

[0046] In this specification, it is considered that the atomic ratio of In to element M in region A1 is larger than the atomic ratio of In to element M in region B1. Therefore, in this specification, region A1 is referred to as an In-rich region, and region B1 is referred to as an In-poor region.

[0047] For example, the concentration of In in region A1 is 1.1 times or more, preferably 2 times or more and 10 times or less than that in region B1. Region A1 may be an oxide containing at least In, and elements M and Zn do not necessarily have to be included.

[0048] <Atomic ratio> Here, the atomic ratio of the elements of the composite oxide semiconductor according to one aspect of the present invention will be described.

[0049] In the oxide semiconductor of the present invention, for example, when region A1 contains In, element M, and Zn, the atomic ratio of each element can be shown using the phase diagram shown in FIG. 5. The atomic ratio of In, element M, and Zn is represented as x:y:z using x, y, and z. Here, the atomic ratio can be represented in the figure as coordinates (x:y:z). Note that FIG. 5 does not show the atomic ratio of oxygen. ​​​​​​​​​

[0050] In Fig. 5, the dashed lines represent the lines with the atomic number ratios of [In]:[M]:[Zn] = (1+α):(1-α):1 (-1≤α≤1), the lines with the atomic number ratios of [In]:[M]:[Zn] = (1+α):(1-α):2, the lines with the atomic number ratios of [In]:[M]:[Zn] = (1+α):(1-α):3, the lines with the atomic number ratios of [In]:[M]:[Zn] = (1+α):(1-α):4, and the lines with the atomic number ratios of [In]:[M]:[Zn] = (1+α):(1-α):5. Also, the dotted lines represent the lines with the atomic number ratios of [In]:[M]:[Zn] = 1:1:β (β≥0), the lines with the atomic number ratios of [In]:[M]:[Zn] = 1:2:β, the lines with the atomic number ratios of [In]:[M]:[Zn] = 1:3:β, the lines with the atomic number ratios of [In]:[M]:[Zn] = 1:4:β, the lines with the atomic number ratios of [In]:[M]:[Zn] = 1:7:β, the lines with the atomic number ratios of [In]:[M]:[Zn] = 2:1:β, and the lines with the atomic number ratios of [In]:[M]:[Zn] = 5:1:β. Moreover, the oxide semiconductor with the atomic number ratio of [In]:[M]:[Zn] = 0:2:1 or values in the vicinity thereof shown in Fig. 5 tends to have a spinel-type crystal structure. The region A2 shown in Fig. 5 shows an example of the preferable range of the atomic number ratios of indium, element M, and zinc that the region A1 has. Note that the region A2 also includes the lines with the atomic number ratios of [In]:[M]:[Zn] = (1+γ):0:(1-γ) (-1≤γ≤1).

[0051]

[0052]

[0053] ​​​​​​​​​​​​​​

[0054] Region B2 shown in FIG. 5 shows an example of a preferable range of the atomic number ratios of indium, element M, and zinc that region B1 has. Note that region B2 includes [In]:[M]:[Zn] = 4:2:3 to 4.1, and values in the vicinity thereof. The values in the vicinity include, for example, an atomic number ratio of In]:[M]:[Zn] = 5:3:4. Also, region B2 includes [In]:[M :[Zn] = 5:1:6, and values in the vicinity thereof.

[0055] Since the concentration of In in region A2 is high, its conductivity is higher than that of region B2, and it has a function of increasing the carrier mobility (field-effect mobility). Therefore, the on-current and carrier mobility of a transistor using an oxide semiconductor having region A1 can be increased.

[0056] On the other hand, since the concentration of In in region B2 is low, its conductivity is lower than that of region A2, and it has a function of reducing the leakage current. Therefore, the off-current of a transistor using an oxide semiconductor having region B1 can be reduced.

[0057] In the oxide semiconductor of the present invention, region A1 and region B1 form a composite. That is, in region A1, carrier movement easily occurs, and in region B1, carrier movement hardly occurs. Therefore, the oxide semiconductor of the present invention can be used as a material having high carrier mobility and high switching characteristics and good semiconductor characteristics.

[0058] As an example, as shown in FIG. 1(A), region A1 is basically formed in a shape close to a circle in the a-b plane direction. Also, as shown in FIG. 1(B), region A1 is in the c-axis direction ​​​​​​​​Basically, it is formed in a shape close to an ellipse. Therefore, region A1 is island-shaped and can exist in a state of being three-dimensionally surrounded by region B1. That is, region A1 has a structure that is enclosed by region B1.

[0059] Also, as shown in FIGS. 1(A) and 1(B), region A1 is irregularly distributed in region B1. Therefore, a plurality of regions A1 may be connected and exist. That is, a plurality of regions A1 may have a shape in which circles are superimposed in the a-b plane direction, or a shape in which ellipses are connected at their ends in the c-axis direction. However, if all regions A1 are connected in the a-b plane direction, the switching characteristics of the transistor, for example, the off-current of the transistor will increase. Therefore, as shown in FIGS. 1(A) and 1(B), it is preferable that region A1 is scattered within region B1.

[0060] Note that the ratio of the scattered regions A1 can be adjusted according to the production conditions or composition of the complex oxide semiconductor. For example, as shown in FIG. 2, a complex oxide semiconductor with a small ratio of region A1, or, as shown in FIG. 3, a complex oxide semiconductor with a large ratio of region A1 can be formed. Also, in the complex oxide semiconductor of the present invention, the ratio of region A1 to region B1 is not necessarily small. In a complex oxide semiconductor with a very large ratio of region A1, region B1 may be formed within region A1 depending on the observation range.

[0061] Also, for example, the size of the island shape formed by region A1 can be appropriately adjusted according to the production conditions or composition of the complex oxide semiconductor. In FIGS. 1 to 3, various sizes Although a conceptual diagram showing an island-shaped region of the oxide has been shown, as shown in FIG. 4, regions A1 of the same size may be scattered. There may be cases where regions A1 of the same size are scattered.

[0062] In addition, there may be cases where a clear boundary cannot be observed between region A1 and region B1. Note that the sizes of region A1 and region B1 can be evaluated by EDX mapping. For example, in the EDX mapping of a cross-sectional photograph, the thickness (also referred to as the diameter) of region A1 may be observed to be 0.1 nm or more and 5 nm or less, or 0.3 nm or more and 3 nm or less for region A1. Preferably, the thickness of region A1 is 0.1 nm or more and 1 nm or less. In addition, there may be cases where a clear boundary cannot be observed between region A1 and region B1. Note that the sizes of region A1 and region B1 can be evaluated by EDX mapping. For example, in the EDX mapping of a cross-sectional photograph, the thickness (also referred to as the diameter) of region A1 may be observed to be 0.1 nm or more and 5 nm or less, or 0.3 nm or more and 3 nm or less for region A1. Preferably, the thickness of region A1 is 0.1 nm or more and 1 nm or less. In addition, there may be cases where a clear boundary cannot be observed between region A1 and region B1. Note that the sizes of region A1 and region B1 can be evaluated by EDX mapping. For example, in the EDX mapping of a cross-sectional photograph, the thickness (also referred to as the diameter) of region A1 may be observed to be 0.1 nm or more and 5 nm or less, or 0.3 nm or more and 3 nm or less for region A1. Preferably, the thickness of region A1 is 0.1 nm or more and 1 nm or less. In addition, there may be cases where a clear boundary cannot be observed between region A1 and region B1. Note that the sizes of region A1 and region B1 can be evaluated by EDX mapping. For example, in the EDX mapping of a cross-sectional photograph, the thickness (also referred to as the diameter) of region A1 may be observed to be 0.1 nm or more and 5 nm or less, or 0.3 nm or more and 3 nm or less for region A1. Preferably, the thickness of region A1 is 0.1 nm or more and 1 nm or less. In addition, there may be cases where a clear boundary cannot be observed between region A1 and region B1. Note that the sizes of region A1 and region B1 can be evaluated by EDX mapping. For example, in the EDX mapping of a cross-sectional photograph, the thickness (also referred to as the diameter) of region A1 may be observed to be 0.1 nm or more and 5 nm or less, or 0.3 nm or more and 3 nm or less for region A1. Preferably, the thickness of region A1 is 0.1 nm or more and 1 nm or less.

[0063] Thus, the oxide semiconductor according to one aspect of the present invention is a composite oxide semiconductor in which region A1 and region B1 are mixed, and the functions of region A1 and region B1 are different from each other, and region A1 and region B1 function complementarily. For example, in the case of an In-Ga-Zn oxide (hereinafter referred to as IGZO) with element M being Ga, the oxide semiconductor according to one aspect of the present invention can be referred to as Complementary IGZO (abbreviation: C / IGZO). Thus, the oxide semiconductor according to one aspect of the present invention is a composite oxide semiconductor in which region A1 and region B1 are mixed, and the functions of region A1 and region B1 are different from each other, and region A1 and region B1 function complementarily. For example, in the case of an In-Ga-Zn oxide (hereinafter referred to as IGZO) with element M being Ga, the oxide semiconductor according to one aspect of the present invention can be referred to as Complementary IGZO (abbreviation: C / IGZO). Thus, the oxide semiconductor according to one aspect of the present invention is a composite oxide semiconductor in which region A1 and region B1 are mixed, and the functions of region A1 and region B1 are different from each other, and region A1 and region B1 function complementarily. For example, in the case of an In-Ga-Zn oxide (hereinafter referred to as IGZO) with element M being Ga, the oxide semiconductor according to one aspect of the present invention can be referred to as Complementary IGZO (abbreviation: C / IGZO). Thus, the oxide semiconductor according to one aspect of the present invention is a composite oxide semiconductor in which region A1 and region B1 are mixed, and the functions of region A1 and region B1 are different from each other, and region A1 and region B1 function complementarily. For example, in the case of an In-Ga-Zn oxide (hereinafter referred to as IGZO) with element M being Ga, the oxide semiconductor according to one aspect of the present invention can be referred to as Complementary IGZO (abbreviation: C / IGZO). Thus, the oxide semiconductor according to one aspect of the present invention is a composite oxide semiconductor in which region A1 and region B1 are mixed, and the functions of region A1 and region B1 are different from each other, and region A1 and region B1 function complementarily. For example, in the case of an In-Ga-Zn oxide (hereinafter referred to as IGZO) with element M being Ga, the oxide semiconductor according to one aspect of the present invention can be referred to as Complementary IGZO (abbreviation: C / IGZO).

[0064] On the other hand, for example, in the case of a configuration in which region A1 and region B1 are laminated in layers, there is no interaction or the interaction is unlikely to occur between region A1 and region B1, so the functions of region A1 and region B1 may function independently of each other. In this case, even if the carrier mobility can be increased by region A1, there may be cases where the off-current of the transistor becomes high. Therefore, by using the above-described composite oxide semiconductor or C / IGZO, it is possible to simultaneously have a function of high carrier mobility and a function of good switching characteristics. On the other hand, for example, in the case of a configuration in which region A1 and region B1 are laminated in layers, there is no interaction or the interaction is unlikely to occur between region A1 and region B1, so the functions of region A1 and region B1 may function independently of each other. In this case, even if the carrier mobility can be increased by region A1, there may be cases where the off-current of the transistor becomes high. Therefore, by using the above-described composite oxide semiconductor or C / IGZO, it is possible to simultaneously have a function of high carrier mobility and a function of good switching characteristics. On the other hand, for example, in the case of a configuration in which region A1 and region B1 are laminated in layers, there is no interaction or the interaction is unlikely to occur between region A1 and region B1, so the functions of region A1 and region B1 may function independently of each other. In this case, even if the carrier mobility can be increased by region A1, there may be cases where the off-current of the transistor becomes high. Therefore, by using the above-described composite oxide semiconductor or C / IGZO, it is possible to simultaneously have a function of high carrier mobility and a function of good switching characteristics. On the other hand, for example, in the case of a configuration in which region A1 and region B1 are laminated in layers, there is no interaction or the interaction is unlikely to occur between region A1 and region B1, so the functions of region A1 and region B1 may function independently of each other. In this case, even if the carrier mobility can be increased by region A1, there may be cases where the off-current of the transistor becomes high. Therefore, by using the above-described composite oxide semiconductor or C / IGZO, it is possible to simultaneously have a function of high carrier mobility and a function of good switching characteristics. On the other hand, for example, in the case of a configuration in which region A1 and region B1 are laminated in layers, there is no interaction or the interaction is unlikely to occur between region A1 and region B1, so the functions of region A1 and region B1 may function independently of each other. In this case, even if the carrier mobility can be increased by region A1, there may be cases where the off-current of the transistor becomes high. Therefore, by using the above-described composite oxide semiconductor or C / IGZO, it is possible to simultaneously have a function of high carrier mobility and a function of good switching characteristics. On the other hand, for example, in the case of a configuration in which region A1 and region B1 are laminated in layers, there is no interaction or the interaction is unlikely to occur between region A1 and region B1, so the functions of region A1 and region B1 may function independently of each other. In this case, even if the carrier mobility can be increased by region A1, there may be cases where the off-current of the transistor becomes high. Therefore, by using the above-described composite oxide semiconductor or C / IGZO, it is possible to simultaneously have a function of high carrier mobility and a function of good switching characteristics. This is an excellent effect that can be obtained with the complex oxide semiconductor of the present invention.

[0065] When an oxide semiconductor film is formed using a sputtering apparatus, the atomic ratio of the target is In particular, depending on the substrate temperature during film formation, the ratio of the number of atoms in [Zn] may change. As a result, the atomic ratio of the film may become smaller than that of the target.

[0066] In addition, the characteristics of the complex oxide semiconductor according to one embodiment of the present invention are uniquely determined by the atomic ratio. Therefore, the illustrated region is a region A1 and a region B1 of the complex oxide semiconductor. The boundary is not strict.

[0067] Here, the oxide semiconductor includes a single-crystal oxide semiconductor and a non-single-crystal oxide semiconductor other than the single-crystal oxide semiconductor. As non-single-crystal oxide semiconductors, CAAC-OS (c-axis axially aligned oxide semiconductors) gned crystalline oxide semiconductor), polycrystalline Nanocrystalline oxide semiconductor, nc-OS conductor), pseudo-amorphous oxide semiconductor (a-like OS) us-like oxide semiconductor) and amorphous oxide semiconductor etc.

[0068] CAAC-OS has a c-axis orientation and multiple nanocrystals are connected in the ab-plane direction. The crystal structure is distorted.

[0069] The nc-OS is a nano-sized area (e.g., an area of ​​1 nm to 10 nm, especially 1 nm to 3 nm). The nc-OS has periodic atomic arrangement in the nanometer range. There is no regularity in the crystal orientation between crystals. Therefore, no orientation is observed in the entire film. Thus, depending on the analysis method, nc-OS may not be distinguishable from a-like OS or an amorphous oxide semiconductor.

[0070] a-like OS is an oxide semiconductor having a structure between nc-OS and an amorphous oxide semiconductor. a-like OS has a loose or low-density region. That is, a-like OS has an unstable structure compared with nc-OS and CAAC-OS.

[0071] Oxide semiconductors take various structures, and each has various characteristics. The oxide semiconductor of the present invention may be a composite oxide semiconductor having two or more of an amorphous oxide semiconductor, a-like OS, nc-OS, and CAAC-OS.

[0072] For example, region A1 is preferably non-single crystal. On the other hand, region B1 preferably has at least one of regions such as CAAC-OS, a polycrystalline oxide semiconductor, and nc-OS. Further, region A1 and region B1 may have different crystals.

[0073] <Transistor having an oxide semiconductor> Subsequently, the case where the above oxide semiconductor is used for a transistor will be described.

[0074] Note that by using the above composite oxide semiconductor for a transistor, a transistor with high carrier mobility and high switching characteristics can be realized. Further, a highly reliable transistor can be realized.

[0075] Also, it is preferable to use an oxide semiconductor with a low carrier density. For example, for example, the oxide semiconductor has a carrier density of 8 × 10 11 / cm 3 less than, preferably 1 × 10 11 / cm 3 less than, more preferably 1 × 10 10 / cm 3 less than, and 1 × 10 -9 / cm 3 or more is sufficient.

[0076] Note that an oxide semiconductor that is highly pure intrinsic or substantially highly pure intrinsic has few carrier generation sources, so the carrier density can be lowered. Also, an oxide semiconductor that is highly pure intrinsic or substantially highly pure intrinsic has a low density of defect levels, so there are cases where the trap level density is also low.

[0077] Also, the charge trapped in the trap levels of the oxide semiconductor takes a long time to disappear and may behave as if it were a fixed charge. Therefore, a transistor in which a channel region is formed in an oxide semiconductor with a high trap level density may have unstable electrical characteristics.

[0078] Therefore, in order to stabilize the electrical characteristics of the transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Also, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to reduce the impurity concentration in the adjacent film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, etc.

[0079] Here, the effects of various impurities in the oxide semiconductor will be described.

[0080] In an oxide semiconductor, when silicon or carbon, which is one of the Group 14 elements, is contained, defects levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (the concentration obtained by secondary ion mass spectrometry ( SIMS: Secondary Ion Mass Spectrometry)) are set to 2×10 atoms / cm or less, preferably 2×10 18 atoms / cm 3 or less. 17 at oms / cm 3

[0081] In addition, when an alkali metal or an alkaline earth metal is contained in the oxide semiconductor, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal tends to have normally-on characteristics. For this reason, it is preferable to reduce the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor. Specifically, the concentration of the alkali metal or the alkaline earth metal in the oxide semiconductor obtained by SIMS is set to 1×10 atoms / cm or less, preferably 2×10 atoms / cm or less. 18 atoms / cm 3 1 6 atoms / cm 3

[0082] In addition, in the oxide semiconductor, when nitrogen is contained, electrons as carriers are generated, the carrier density increases, and it tends to be n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Therefore, in the oxide semiconductor, ​​​​​It is preferable that the nitrogen content is as low as possible. For example, the nitrogen concentration in the oxide semiconductor is The degree is 5×10 in SIMS. 19 atoms / cm 3 Less than 5 x 10 1 8 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 The following is further Preferably 5 x 10 17 atoms / cm 3 The following applies.

[0083] In addition, hydrogen contained in the oxide semiconductor reacts with oxygen that bonds with metal atoms to form water. , oxygen deficiency (V o ) may be formed. o ) hydrogen enters the In some cases, electrons that are carriers are generated. In other cases, some of the hydrogen atoms are bonded to the metal atoms. It can combine with hydrogen to produce electrons, which act as carriers. Transistors using oxide semiconductors tend to be normally-on. It is preferable that the amount of hydrogen in the semiconductor is reduced as much as possible. Specifically, the amount of hydrogen in the oxide semiconductor is reduced as much as possible. The hydrogen concentration obtained by SIMS is 1×10 20 atoms / cm 3 less than, Preferably 1 x 10 19 atoms / cm 3 less than 5×10 18 atom s / cm 3 less than 1×10 18 atoms / cm 3 Less than.

[0084] In addition, oxygen vacancies (V o ) is a method to introduce oxygen into an oxide semiconductor, It can be reduced. That is, oxygen fills the oxygen vacancies (V o ) in the oxide semiconductor so that the oxygen vacancies (V o ) disappear. Therefore, by diffusing oxygen into the oxide semiconductor , the oxygen vacancies (V o ) of the transistor can be reduced and the reliability can be improved.

[0085] As a method of introducing oxygen into the oxide semiconductor, for example, an oxide containing more oxygen than oxygen satisfying the stoichiometric composition can be provided in contact with the oxide semiconductor. That is, in the oxide, it is preferable that a region where oxygen is present in excess of the stoichiometric composition (hereinafter also referred to as the excess oxygen region) is formed. In particular, when an oxide semiconductor is used in a transistor , by providing an oxide having an excess oxygen region in the underlying film or the interlayer film near the transistor , the oxygen vacancies of the transistor can be reduced and the reliability can be improved. By using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of the transistor

[0086] , stable electrical characteristics can be imparted.

[0087] <Fabrication method of oxide semiconductor> Hereinafter, an example of a method for forming an oxide semiconductor by a sputtering method will be described.

[0088] When forming the oxide semiconductor, the temperature is preferably set to be equal to or higher than room temperature and lower than 140°C . Note that room temperature includes not only the case where temperature control is not performed but also the case where temperature control is performed .

[0089] Also, the sputtering gas is a noble gas (typically argon), oxygen, a noble gas, and oxygen A mixed gas is used as appropriate. In the case of a mixed gas, the gas ratio of oxygen to the rare gas is 5% or more and 30 % or less, preferably 7% or more and 20% or less.

[0090] Note that when oxygen is included in the sputtering gas, oxygen can be added to the underlying film simultaneously with the formation of the oxide semiconductor film, and an oxygen-excess region can be provided. Also, high-purity purification of the sputtering gas is necessary. For example, the oxygen gas and argon gas used as the sputtering gas should have a dew point of -40°C or lower, preferably -80°C or lower, more preferably -100°C or lower, and most preferably -120°C or lower. By using a highly purified gas, the incorporation of moisture and the like into the oxide semiconductor can be prevented as much as possible.

[0091] Also, when forming an oxide semiconductor film by sputtering, the chamber in the sputtering apparatus should be evacuated to a high vacuum (from 5×10 Pa to about 1×10 Pa) using an adsorption-type vacuum exhaust pump such as a cryopump to remove water and other impurities that can become impurities for the oxide semiconductor as much as possible. Alternatively, it is preferable to combine a turbo molecular pump and a cold trap to prevent the backflow of gas, especially gas containing carbon or hydrogen, from the exhaust system into the chamber. -7 - 4

[0092] Also, as the target, an In-Ga-Zn metal oxide target can be used. For example, [In]:[Ga]:[Zn]=4:2:4.1 [atomic ratio], or [In :[Ga]:[Zn]=5:1:6 [atomic ratio], or a metal oxide target with an atomic ratio close to these values is preferably used. ​​​​​​​​​​

[0093] Also, in the sputtering apparatus, the target may be rotated or moved. For example by oscillating the magnet unit vertically or / and horizontally during film formation, the composite oxide semiconductor of the present invention can be formed. For example, the target is set to 0.1 Hz or more and 1 kHz or less beats (which may also be referred to as rhythm, pulse, frequency, period or cycle, etc.). It may be rotated or moved. Or, the magnet unit may be oscillated at a beat of 0 .1 Hz or more and 1 kHz or less. Details of the sputtering apparatus will be described in the following embodiments.

[0094] For example, as the sputtering gas, a rare gas with an oxygen gas ratio of about 10%, and a mixed gas of oxygen are used, the substrate temperature is set to 130 °C, and [In]:[Ga]:[Zn]=4:2:4 .1 [atomic ratio] In-Ga-Zn metal oxide target is oscillated while film formation is performed to form the oxide semiconductor of the present invention.

[0095] First, the rare gas or oxygen gas is ionized in the film formation chamber and separated into cations and electrons to form plasma . The cations in the plasma are accelerated toward the target by the potential applied to the target holder . When the cations collide with the In-Ga-Zn metal oxide target , sputtered particles are generated and the sputtered particles are deposited on the substrate.

[0096] First, when the cations collide with the In-Ga-Zn metal oxide target, relative atomic mass Ga and Zn, which are lighter than In, are preferentially ejected from the target. Ejected ​The emitted In, Ga, and Zn combine with oxygen and deposit on the substrate, forming region B1 is formed. At this time, In segregates on the surface of the target.

[0097] Subsequently, the In segregated on the surface of the target forms a structure like a plurality of particles and is ejected from the target. The segregated In with a structure like a plurality of particles combines with oxygen, collides with the previously formed region B1, and spreads in a shape close to a circle, depositing the island-shaped region A1. Since the segregated In is ejected, In, Ga, and Zn exist on the surface of the target in a state close to the original atomic ratio.

[0098] Here, further, when cations collide with the target, Ga and Zn, whose relative atomic mass is lighter than that of In, are preferentially ejected from the target. At this time, In segregates on the surface of the target. Again, region B1 deposits on the previously formed region B 1 and region A1, and region B1 is formed so as to sandwich region A1.

[0099] In segregates in one region of the target surface, and in another region of the target surface, the segregated In is ejected. That is, the mechanism by which In segregates and the mechanism by which the segregated In is ejected occur simultaneously, so that region A1 is sandwiched by region B1 and has an irregularly distributed structure.

[0100] By going through the film formation model as described above, it is considered that a composite oxide semiconductor in which region A1 and region B1 are mixed, as shown in FIGS. 1 to 4, is formed.

[0101] ​​​​​​The oxide semiconductor of the present invention has a region A1 with a large amount of In composed of the atomic ratio shown in region A2 and a region B1 with a small amount of In composed of the atomic ratio shown in region B2 are mixed and combined to form an oxide semiconductor. That is, carrier movement is likely to occur in region A1, and in region B 1, carrier movement is unlikely to occur. Therefore, the oxide semiconductor of the present invention has a high carrier movement degree and high switching characteristics, and can be used as a material with good semiconductor characteristics can.

[0102] As described above, the configuration shown in the present embodiment can be appropriately combined with the configurations shown in other embodiments or other examples and used.

[0103] (Embodiment 2) In the present embodiment, a sputtering apparatus and a film forming apparatus capable of forming an oxide of one aspect of the present invention will be described with reference to FIGS. 6 to 11. Note that in the sputtering apparatus shown below, for ease of understanding or for explaining the operation during film formation , it is shown in a state where a substrate and a target are arranged. However, since the substrate and the target are installed by the user, the sputtering apparatus according to one aspect of the present invention may not have a substrate and a target. a target.

[0104] <Sputtering apparatus> As the sputtering apparatus, for example, a parallel plate type sputtering apparatus and a facing target type sputtering apparatus can be used. Note that the film forming method using a parallel plate type sputtering apparatus is called PESP (parallel electrode SP) can also. Further, the film forming method using a facing target type sputtering apparatus is called VDSP (v can also. It can also be called physical vapor deposition (PVD).

[0105] [Parallel plate type sputtering apparatus (PESP)] First, the parallel plate type sputtering apparatus will be described. FIG. 6(A) is a cross-sectional view of a film formation chamber 601 which is a parallel plate type sputtering apparatus. The film formation chamber 601 shown in FIG. 6(A) has a target holder 620, a backing plate 610, a target 600, and a magnet unit 630, and a substrate holder 670. Note that the target 600 is arranged on the backing plate 610. Also, the backing plate 610 is arranged on the tar get holder 620. Further, the magnet unit 630 is arranged under the target 600 via the backing plate 610. Also, the substrate holder 670 is arranged facing the tar get 600. In this specification, a combination of a plurality of magnets (magnetic stones) is called a magnet unit. The magnet unit can also be referred to as a cathode , a cathode magnet, a magnetic member, a magnetic component, etc. The magnet unit 630 has a magnet 630N, a magnet 630S, and a magnet holder 6 32. Note that in the magnet unit 630, the magnet 630N and the magnet 630S are arranged on the magnet holder 632. Also, the magnet 6 30N is arranged at an interval from the magnet 630S. When the substrate 6 60 is carried into the film formation chamber 601, the substrate 660 is arranged on the substrate holder 670.

[0106] The target holder 620 and the backing plate 610 are connected using screws (bolts, etc). It is fixed and at an equipotential. Further, the target holder 620 has a function of supporting the target 600 via the backing plate 610.

[0107] Also, the target 600 is fixed to the backing plate 610. For example, the backing plate 610 and the target 600 can be fixed by a bonding material containing a low melting point metal such as indium.

[0108] Fig. 6(A) shows magnetic field lines 680a and magnetic field lines 680b formed by the magnet unit 630.

[0109] The magnetic field line 680a is one of the magnetic field lines that form a horizontal magnetic field near the upper surface of the target 600. The vicinity of the upper surface of the target 600 is, for example, a region where the vertical distance from the target 600 is 0 mm or more and 10 mm or less, particularly 0 mm or more and 5 mm or less.

[0110] The magnetic field line 680b is one of the magnetic field lines that form a horizontal magnetic field at a vertical distance d from the upper surface of the magnet unit 630. The vertical distance d is, for example, 0 mm or more and 20 mm or less or 5 mm or more and 15 mm or less.

[0111] At this time, by using the strong magnet 630N and the strong magnet 630S, a strong magnetic field can also be generated near the upper surface of the substrate 660. Specifically, the magnetic flux density of the horizontal magnetic field on the upper surface of the substrate 660 can be set to 10 G or more and 100 G or less, preferably 15 G or more and 60 G or less, and more preferably 20 G or more and 40 G or less.

[0112] Note that the magnetic flux density of the horizontal magnetic field can be measured by measuring the value when the magnetic flux density of the vertical magnetic field is 0 G. Good.

[0113] By setting the magnetic flux density of the magnetic field in the film formation chamber 601 within the above-described range, a high-density, highly crystalline oxide can be formed. Further, the obtained oxide contains a plurality of crystal phases and has few defects and becomes an oxide containing almost a single crystal phase.

[0114] Fig. 6(B) shows a top view of the magnet unit 630. The magnet unit 630 includes a circular or substantially circular magnet 630N and a circular or substantially circular magnet 630S which are fixed to the magnet holder 632. Then, the magnet unit 630 can be rotated with the normal vector at the center or substantially at the center on the upper surface of the magnet unit 630 as the rotation axis. For example, the magnet unit 630 can be rotated at a beat (which can also be described as rhythm, tempo, pulse, frequency, period or cycle, etc.) of 0.1 Hz or more and 1 kHz or less.

[0115] Therefore, the region with a strong magnetic field on the target 600 changes as the magnet unit 630 rotates. Since the region with a strong magnetic field becomes a high-density plasma region, sputtering of the target 600 is likely to occur in its vicinity. For example, when the region with a strong magnetic field becomes a specific location, only a specific region of the target 600 will be used. On the other hand, as shown in Fig. 6(B), by rotating the magnet unit 630, plasma 640 is generated between the target 60 0 and the substrate 660, so that the target 600 can be used uniformly. Also, by rotating the magnet unit 630, a film having a uniform thickness and a uniform quality can be formed. ​

[0116] Also, by rotating the magnet unit 630, the direction of the magnetic force lines on the upper surface of the substrate 660 can also be changed. The direction of the magnetic force lines on the upper surface of the substrate 660 can also be changed.

[0117] Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined. Here, an example of rotating the magnet unit 630 is shown, but one aspect of the present invention is not limited thereto. For example, the magnet unit 630 may be swung up and down or / and left and right. For example, the magnet unit 630 may be swung at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the direction of the magnetic force lines on the upper surface of the substrate 660 may be relatively changed. Alternatively, these may be combined.

[0118] The film forming chamber 601 may have a water channel inside or below the backing plate 610. By flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, it is possible to suppress discharge abnormalities due to an increase in the temperature of the target 600 during sputtering and damage to the film forming chamber 601 due to deformation of the members. At this time, it is preferable to closely adhere the backing plate 610 and the target 600 via a bonding material because the cooling performance is enhanced. The film forming chamber 601 may have a water channel inside or below the backing plate 610. By flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, it is possible to suppress discharge abnormalities due to an increase in the temperature of the target 600 during sputtering and damage to the film forming chamber 601 due to deformation of the members. At this time, it is preferable to closely adhere the backing plate 610 and the target 600 via a bonding material because the cooling performance is enhanced. The film forming chamber 601 may have a water channel inside or below the backing plate 610. By flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, it is possible to suppress discharge abnormalities due to an increase in the temperature of the target 600 during sputtering and damage to the film forming chamber 601 due to deformation of the members. At this time, it is preferable to closely adhere the backing plate 610 and the target 600 via a bonding material because the cooling performance is enhanced. The film forming chamber 601 may have a water channel inside or below the backing plate 610. By flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, it is possible to suppress discharge abnormalities due to an increase in the temperature of the target 600 during sputtering and damage to the film forming chamber 601 due to deformation of the members. At this time, it is preferable to closely adhere the backing plate 610 and the target 600 via a bonding material because the cooling performance is enhanced. The film forming chamber 601 may have a water channel inside or below the backing plate 610. By flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, it is possible to suppress discharge abnormalities due to an increase in the temperature of the target 600 during sputtering and damage to the film forming chamber 601 due to deformation of the members. At this time, it is preferable to closely adhere the backing plate 610 and the target 600 via a bonding material because the cooling performance is enhanced.

[0119] In addition, it is preferable to have a gasket between the target holder 620 and the backing plate 610 because it is difficult for impurities to enter the film forming chamber 601 from the outside or the water channel. In addition, it is preferable to have a gasket between the target holder 620 and the backing plate 610 because it is difficult for impurities to enter the film forming chamber 601 from the outside or the water channel.

[0120] In the magnet unit 630, the magnet 630N and the magnet 630S are arranged such that they face different poles toward the target 600 side. Here, a case will be described in which the magnet 630N is arranged such that the target 600 side becomes the N pole, and the magnet 630S is arranged such that the target 600 side becomes the S pole. However, the arrangement of the magnets and poles in the magnet unit 630 is not limited to this arrangement. Moreover, it is not limited to the arrangement in Fig. 6(A). Also, it is not limited to the arrangement in Fig. 6(A). During film formation, the potential V1 applied to the terminal V1 connected to the target holder 620 is, for example, lower than the potential V2 applied to the terminal V2 connected to the substrate holder 670. Also, the potential V2 applied to the terminal V2 connected to the substrate holder 670 is, for example, the ground potential. Also, the potential V3 applied to the terminal V3 connected to the magnet holder 632 is, for example, the ground potential. Note that the potentials applied to the terminal V1, the terminal V2, and the terminal V3 are not limited to the above potentials. Also, potentials do not have to be applied to all of the target holder 620, the substrate holder 670, and the magnet holder 632. For example, the substrate holder 670 may be electrically

[0121] floating. In Fig. 6(A), an example of the so-called DC sputtering method in which the potential V1 is applied to the terminal V1 connected to the target holder 620 is shown, but one aspect of the present invention is not limited to this. For example, a so-called RF sputtering ring method in which a high-frequency power source having a frequency of 13.56 MHz or 27.12 MHz is connected to the target holder 620 may be used. Moreover, it is not limited to the arrangement in Fig. 6(A). Also, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A). Moreover, it is not limited to the arrangement in Fig. 6(A).

[0122] In addition, in FIG. 6(A), an example is shown where the backing plate 610 and the target holder 620 are not electrically connected to the magnet unit 630 and the magnet holder 632, but the present invention is not limited to this. For example, the backing plate 610 and the target holder 620 may be electrically connected to the magnet unit 630 and the magnet holder 632 to be at the same electric potential. Also, the example where the backing plate 610 and the target holder 620 are not electrically connected to the magnet unit 630 and the magnet holder 632 is shown, but the present invention is not limited to this. For example, the backing plate 610 and the target holder 620 may be electrically connected to the magnet unit 630 and the magnet holder 632 to be at the same electric potential. In addition, in order to further enhance the crystallinity of the obtained oxide, the temperature of the substrate 660 may be increased. Increasing the temperature of the substrate 660 can promote the migration of sputtered particles on the upper surface of the substrate 660.

[0123] Thus, an oxide with higher density and higher crystallinity can be formed. The temperature of the substrate 660 may be, for example, 100 °C or higher and 450 °C or lower, preferably 150 °C or higher and 400 °C or lower, and more preferably 170 °C or higher and 350 °C or lower. In addition, if the oxygen partial pressure in the film-forming gas is too high, an oxide containing a plurality of crystal phases is likely to be formed. Therefore, it is preferable to use a mixed gas of a noble gas such as argon (helium, neon, krypton, xenon, etc.) and oxygen as the film-forming gas. For example, the proportion of oxygen in the whole may be less than 50% by volume, preferably 33% by volume or less, more preferably 20% by volume or less, and even more preferably 15% by volume or less. Also, the vertical distance between the target 600 and the substrate 660 is 10 mm or more and 600 mm or less, preferably 20 mm or more and 400 mm or less, and more preferably 30 mm or more and 200 mm or less.

[0124] In addition, if the oxygen partial pressure in the film-forming gas is too high, an oxide containing a plurality of crystal phases is likely to be formed. Therefore, it is preferable to use a mixed gas of a noble gas such as argon (helium, neon, krypton, xenon, etc.) and oxygen as the film-forming gas. For example, the proportion of oxygen in the whole may be less than 50% by volume, preferably 33% by volume or less, more preferably 20% by volume or less, and even more preferably 15% by volume or less. In addition, if the oxygen partial pressure in the film-forming gas is too high, an oxide containing a plurality of crystal phases is likely to be formed. Therefore, it is preferable to use a mixed gas of a noble gas such as argon (helium, neon, krypton, xenon, etc.) and oxygen as the film-forming gas.

[0125] In addition, the vertical distance between the target 600 and the substrate 660 is 10 mm or more and 600 mm or less, preferably 20 mm or more and 400 mm or less, and more preferably 30 mm or more and 200 mm or less. Preferably, it is 20 mm or more and 400 mm or less, and more preferably 30 mm or more and 200 mm or less. More preferably, it is set to 40 mm or more and 100 mm or less. By making the vertical distance between the target 600 and the substrate 660 close to the above range, the energy decrease of the sputter particles until they reach the substrate 660 can be suppressed in some cases. Also, by making the vertical distance between the target 600 and the substrate 660 far from the above range, the incident direction of the sputter particles to the substrate 660 can be made closer to perpendicular, so that the damage to the substrate 660 due to the collision of the sputter particles can be reduced in some cases. By making the vertical distance between the target 600 and the substrate 660 close to the above range, the energy decrease of the sputter particles until they reach the substrate 660 can be suppressed in some cases. Also, by making the vertical distance between the target 600 and the substrate 660 far from the above range, the incident direction of the sputter particles to the substrate 660 can be made closer to perpendicular, so that the damage to the substrate 660 due to the collision of the sputter particles can be reduced in some cases. By making the vertical distance between the target 600 and the substrate 660 far from the above range, the incident direction of the sputter particles to the substrate 660 can be made closer to perpendicular, so that the damage to the substrate 660 due to the collision of the sputter particles can be reduced in some cases. Figure 7(A) shows an example of a film deposition chamber different from that in Figure 6(A).

[0126] Figure 7(A) shows an example of a film deposition chamber different from that in Figure 6(A).

[0127] The film deposition chamber 601 shown in Figure 7(A) includes a target holder 620a, a target holder 62 0b, a backing plate 610a, a backing plate 610b, a target 6 00a, a target 600b, a magnet unit 630a, a magnet unit 630b, a member 642, and a substrate holder 670. Note that the target 600a is disposed on the backing plate 610a. Also, the backing plate 610a is disposed on the target holder 620a. Also, the magnet unit 630a is disposed under the target 600a via the backing plate 610a. Also, the target 600b is disposed on the backing plate 610b. Also, the backing plate 610b is disposed on the target holder 620b. Also, the magnet unit 63 0b is disposed under the target 600b via the backing plate 610b. The magnet unit 630a includes a magnet 630N1, a magnet 630N2, and a magnet 630N3.

[0128] The magnet unit 630a includes a magnet 630N1, a magnet 630N2, and a magnet 630N3. It has a magnet 630S and a magnet holder 632. Note that in the magnet unit 630a, the magnet 630N1, the magnet 630N2, and the magnet 63 0S are arranged on the magnet holder 632. Also, the magnet 630N1 and the ma gnet 630N2 are arranged at intervals from the magnet 630S. Note that the magnet unit 630b has the same structure as the magnet unit 630a. Note that when the substrate 660 is carried into the film formation chamber 601, the substrate 660 is arranged on the substrate holder 670.

[0129] The target 600a, the backing plate 610a, and the target holder 620a, and the target 600b, the backing plate 610b, and the target holder 620b, are separated by the member 642. Note that the member 642 is preferably an insulator . However, the member 642 may be a conductor or a semiconductor. Also, the member 642 may be a conductor or a semiconductor with its surface covered with an insulator.

[0130] The target holder 620a and the backing plate 610a are fixed using screws (such as bolts) and are at the same electric potential. Also, the target holder 620a has the function of supporting the target 600a via the backing plate 610a. Also, the target holder 620b and the backing plate 610b are fixed using screws (such as bolts) and are at the same electric potential. Also, the target holder 620b has the function of supporting the target 600b via the backing plate 61 0b.

[0131] The backing plate 610a has the function of fixing the target 600a. Also, the ba The mounting plate 610b has a function of fixing the target 600b.

[0132] FIG. 7A shows magnetic field lines 680a and magnetic Field lines 680b are shown.

[0133] The magnetic field lines 680a are the magnetic field lines that form a horizontal magnetic field near the top surface of the target 600a. The vicinity of the upper surface of the target 600a is, for example, a vertical distance from the target 600a. The distance is in the range of 0 mm to 10 mm, particularly in the range of 0 mm to 5 mm.

[0134] The magnetic field lines 680b extend from the top surface of the magnet unit 630a to the horizontal magnetic field at a vertical distance d. The vertical distance d is, for example, 0 mm to 20 mm or is between 5mm and 15mm.

[0135] At this time, the strong magnet 630N1, the strong magnet 630N2 and the strong magnet By using the net 630S, a strong magnetic field is generated even in the vicinity of the upper surface of the substrate 660. Specifically, the magnetic flux density of the horizontal magnetic field on the upper surface of the substrate 660 can be set to 10 G or more. 100G or less, preferably 15G to 60G or less, more preferably 20G to 40G or less It can be below.

[0136] By setting the magnetic flux density of the magnetic field in the film formation chamber 601 within the above range, a film having high density and good crystallinity can be obtained. In addition, the oxide obtained contains multiple crystal phases. The oxide has little crystal structure and is almost entirely made up of a single crystal phase.

[0137] The magnet unit 630b also generates magnetic lines of force similar to those of the magnet unit 630a. is performed.

[0138] Fig. 7(B) shows a top view of the magnet unit 630a and the magnet unit 630b. The magnet unit 630a includes a rectangular or substantially rectangular magnet 630N1, a rectangular or substantially rectangular magnet 630N2, and a rectangular or substantially rectangular magnet 630S, which are fixed to the magnet holder 632. It can be seen that the magnet unit 630a can be swung left and right as shown in Fig. 7(B). For example, the magnet unit 630a can be swung at a beat of 0.1 Hz or more and 1 kHz or less. That is sufficient.

[0139] Therefore, the region with a strong magnetic field on the target 600a changes with the swing of the magnet unit 630a. Since the region with a strong magnetic field becomes a high-density plasma region, sputtering of the target 600a is likely to occur in the vicinity thereof. For example, when the region with a strong magnetic field becomes a specific location, only a specific region of the target 600a will be used. On the other hand, by swinging the magnet unit 630a as shown in Fig. 7(B), plasma 640 is generated between the target 600a and the substrate 660, so that the target 600a can be used uniformly. Also, by swinging the magnet unit 630a, a film having a uniform thickness and quality can be formed.

[0140] Also, by swinging the magnet unit 630a, the state of the magnetic field lines on the upper surface of the substrate 660 can also be changed. This is the same for the magnet unit 630b.

[0141] Here, an example of oscillating the magnet units 630a and 630b has been shown, but one aspect of the present invention is not limited to this. For example, the magnet units 630a and 630b may be rotated. For example, the magnet units 630a and 630b may be rotated at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, the target 600 may be rotated or moved. For example, the target 600 may be rotated or moved at a beat of 0.1 Hz or more and 1 kHz or less. Alternatively, by rotating the substrate 660, the state of the magnetic field lines on the upper surface of the substrate 6 60 can be changed relatively. Or, these may be combined. The film formation chamber 601 may have a water channel inside or below the backing plates 610a and 610b. Then, by flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, abnormal discharges due to the temperature rise of the targets 600a and 600b during sputtering, damage to the film formation chamber 601 due to deformation of the members, etc. can be suppressed. At this time, it is preferable to closely adhere the backing plate 610a and the target 600a via a bonding material because the cooling performance is enhanced. Also, it is preferable to closely adhere the backing plate 610b and the target 600b via a bonding material because the cooling performance is enhanced. In addition, it is preferable to have a gasket between the target holder 620a and the backing plate 610a because it becomes difficult for impurities to enter the film formation chamber 601 from the outside, water channels, etc.

[0142] The film formation chamber 601 may have a water channel inside or below the backing plates 610a and 610b. Then, by flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, abnormal discharges due to the temperature rise of the targets 600a and 600b during sputtering, damage to the film formation chamber 601 due to deformation of the members, etc. can be suppressed. At this time, it is preferable to closely adhere the backing plate 610a and the target 600a via a bonding material because the cooling performance is enhanced. Also, it is preferable to closely adhere the backing plate 610b and the target 600b via a bonding material because the cooling performance is enhanced. The film formation chamber 601 may have a water channel inside or below the backing plates 610a and 610b. Then, by flowing a fluid (such as air, nitrogen, rare gas, water, oil, etc.) through the water channel, abnormal discharges due to the temperature rise of the targets 600a and 600b during sputtering, damage to the film formation chamber 601 due to deformation of the members, etc. can be suppressed. At this time, it is preferable to closely adhere the backing plate 610a and the target 600a via a bonding material because the cooling performance is enhanced. Also, it is preferable to closely adhere the backing plate 610b and the target 600b via a bonding material because the cooling performance is enhanced. When the backing plate 610b and the target 600b are closely adhered via a bonding material, the cooling performance is enhanced, which is preferable.

[0143] In addition, if there is a gasket between the target holder 620a and the backing plate 610a, it is preferable because it becomes difficult for impurities to enter the film formation chamber 601 from the outside, water channels, etc. When there is a gasket between the target holder 620a and the backing plate 610a, it is difficult for impurities to enter the film formation chamber 601 from the outside, water channels, etc., which is preferable. In addition, it is preferable to have a gasket between the target holder 620b and the backing plate 610b. This is because it becomes difficult for impurities to enter the film formation chamber 601 from the outside, water channels, etc.

[0144] In the magnet unit 630a, the magnet 630N1, the magnet 630N 2, and the magnet 630S are arranged with different poles facing the target 600a side, respectively. Here, the magnet 630N1 and the magnet 630N2 are arranged such that the target 60 0a side becomes the N pole, and the case where the magnet 630S is arranged such that the target 600a side becomes the S pole will be described. However, the arrangement of the magnets and poles in the magnet unit 630a is not limited to this arrangement. Also, it is not limited to the arrangement in Fig. 7(A). The same applies to the magnet unit 630b. This is also the case.

[0145] During film formation, the potential applied to the terminal V1 connected to the target holder 620a and the potential applied to the terminal V4 connected to the target holder 620b may alternately change between high and low. Also, the potential applied to the terminal V2 connected to the substrate holder 670 is, for example, the ground potential. Also, the potential applied to the terminal V3 connected to the magnet holder 632 is, for example, the ground potential. Note that the potentials applied to the terminals V1, V2, V3, and V4 are not limited to the above potentials. Also, the potentials do not have to be applied to all of the target holder 620a, the target holder 6 20b, the substrate holder 670, and the magnet holder 632. For example, the substrate holder 670 may be electrically floating. Note that Fig. 7(A) ​​Then, the potential applied to the terminal V1 connected to the target holder 620a and the potential of the target holder The potential applied to the terminal V4 connected to the lead 620b alternates between high and low. However, one embodiment of the present invention is not limited to this.

[0146] In addition, in FIG. 7(A), a backing plate 610a and a target holder 620a are The magnet unit 630a and the magnet holder 632 are not electrically connected. However, the present invention is not limited to the above examples. For example, the backing plate 610a and the tar A get holder 620a, a magnet unit 630a and a magnet holder 632 , may be electrically connected and have the same potential. The magnet unit 630b and the target holder 620b are connected to the magnet 630b. Although an example in which the net holder 632 is not electrically connected has been shown, this is not limiting. For example, a backing plate 610b and a target holder 620b, and a magnet unit The magnet holder 632 is electrically connected to the base 630b and the magnet holder 632, and is at the same potential. It's okay if you are.

[0147] In order to further improve the crystallinity of the resulting oxide, the temperature of the substrate 660 may be increased. By increasing the temperature of the substrate 660, the amount of sputtered particles on the upper surface of the substrate 660 can be reduced. This can promote migration, resulting in a denser, more crystalline structure. The temperature of the substrate 660 is, for example, 100° C. or higher. 450°C or less, preferably 150°C to 400°C, and more preferably 170°C or more The temperature should be 350°C or lower.

[0148] Also, if the oxygen partial pressure in the film-forming gas is too high, an oxide containing a plurality of crystal phases is likely to be formed. Therefore, it is preferable to use a mixed gas of a noble gas such as argon (helium, neon, krypton, xenon, etc.) and oxygen. For example, the proportion of oxygen in the whole is less than 50% by volume, preferably 33% by volume or less, more preferably 20% by volume or less, still more preferably 15% by volume or less.

[0149] Also, the vertical distance between the target 600a and the substrate 660 is set to be 10 mm or more and 600 mm or less, preferably 20 mm or more and 400 mm or less, more preferably 30 mm or more and 200 mm or less , still more preferably 40 mm or more and 100 mm or less. By bringing the vertical distance between the target 600a and the substrate 660 closer to the above range, the energy decrease of the sputtered particles until they reach the substrate 660 can be suppressed in some cases. Also, by increasing the vertical distance between the target 600a and the substrate 660 to the above range, the incident direction of the sputtered particles on the substrate 660 can be made closer to perpendicular, so that the damage to the substrate 660 due to the collision of the sputtered particles can be reduced in some cases.

[0150] Also, the vertical distance between the target 600b and the substrate 660 is set to be 10 mm or more and 600 mm or less, preferably 20 mm or more and 400 mm or less, more preferably 30 mm or more and 200 mm or less , still more preferably 40 mm or more and 100 mm or less. By bringing the vertical distance between the target 600b and the substrate 660 closer to the above range, the energy decrease of the sputtered particles until they reach the substrate 660 can be suppressed in some cases. Also, by increasing the vertical distance between the target 600b and the substrate 660 to the above range, the incident direction of the sputtered particles on the substrate 660 can be made closer to perpendicular, so that the damage to the substrate 660 due to the collision of the sputtered particles By increasing the perpendicular distance from the substrate 660 to the above-mentioned range, the incident direction of the sputter particles on the substrate 660 can be made closer to perpendicular, so that the damage to the substrate 660 caused by the collision of the sputter particles may be reduced.

[0151] [Opposed Target Type Sputtering Apparatus (VDSP)] Next, an opposed target type sputtering apparatus will be described. FIG. 8(A) is a cross-sectional view of a film-forming chamber in an opposed target type sputtering apparatus. The film-forming chamber shown in FIG. 8(A) includes a target 600a and a target 600b, backing plates 610a and 610b for holding the target 600a and the target 600b respectively, and magnet units 630a and 630b disposed on the back surfaces of the target 600a and the target 600b via the backing plates 610a and 610b. Further, a substrate holder 670 is disposed between the target 600a and the target 600b. The substrate holder 670 is disposed above the region where the target 600a and the target 600b face each other (also referred to as the inter-target region). After the substrate 660 is carried into the film-forming chamber, the substrate 660 is fixed to the substrate holder 670.

[0152] Also, as shown in FIG. 8(A), the substrate holder 670 is disposed above the inter-target region, but it may be disposed below. Also, it may be disposed both below and above. By disposing the substrate holder 670 both below and above, two or more substrates can be simultaneously film-formed so that the productivity can be increased.

[0153] Also, as shown in Fig. 8(A), a power source 690 and a power source 691 for applying a potential are connected to the backing plate 610a and the backing plate 610b. It is preferable to use a so-called AC power source in which the level of the potential applied to the backing plate 610a and the level of the potential applied to the backing plate 610b are alternately switched. Also, the power sources 690 and 691 shown in Fig. 8(A) show an example using an AC power source, but it is not limited to this. For example, an RF power source, a DC power source, etc. may be used as the power sources 690 and 691. Or, different types of power sources may be used for the power source 690 and the power source 691. Also, as shown in Fig. 8(A), although the power sources 690 and 691 shown are an example using an AC power source, it is not limited to this. For example, an RF power source, a DC power source, etc. may be used as the power sources 690 and 691. Or, different types of power sources may be used for the power source 690 and the power source 691. For example, an RF power source, a DC power source, etc. may be used as the power sources 690 and 691. Or, different types of power sources may be used for the power source 690 and the power source 691. Or, different types of power sources may be used for the power source 690 and the power source 691.

[0154] Also, the substrate holder 670 is preferably connected to GND. Also, the substrate holder 6 70 may be in a floating state.

[0155] Figs. 8(B) and 8(C) show the potential distribution of the plasma 640 between the dashed-dotted line A - B in Fig. 8(A). The potential distribution shown in Fig. 8(B) shows a state in which a high potential is applied to the backing plate 610a and a low potential is applied to the backing plate 610b. That is, cations are accelerated toward the target 600b. The potential distribution shown in Fig. 8(C) shows a state in which a low potential is applied to the backing plate 610a and a high potential is applied to the backing plate 610b. That is, cations are accelerated toward the target 600a. Film formation can be performed by alternately switching the states of Fig. 8(B) and Fig. 8(C). That is, cations are accelerated toward the target 600b. The potential distribution shown in Fig. 8(C) shows a state in which a low potential is applied to the backing plate 610a and a high potential is applied to the backing plate 610b. That is, cations are accelerated toward the target 600a. Film formation can be performed by alternately switching the states of Fig. 8(B) and Fig. 8(C). That is, cations are accelerated toward the target 600a. Film formation can be performed by alternately switching the states of Fig. 8(B) and Fig. 8(C). That is, cations are accelerated toward the target 600a. Film formation can be performed by alternately switching the states of Fig. 8(B) and Fig. 8(C).

[0156] The configuration shown in Fig. 8(A) is such that the target 600a and the target 600b face each other in parallel. is arranged. Further, the magnet unit 630a and the magnet unit 630b are arranged so that different poles of the magnets face each other. At this time, the magnetic field lines go from the magnet unit 630b to the magnet unit 630a. Therefore, during film formation, the plasma 640 is confined by the magnetic field formed by the magnet unit 630a and the magnet unit 630b. Thus, the substrate holder 670 and the substrate 660 are located outside the plasma 640. Since the substrate 660 is not exposed to the high electric field region of the plasma 640 , damage caused by the plasma 640 can be reduced.

[0157] The opposed target type sputtering apparatus can stably generate plasma even in a high vacuum . For example, film formation is possible even at 0.005 Pa or more and 0.09 Pa or less. Therefore, the concentration of impurities mixed during film formation can be reduced.

[0158] By using the opposed target type sputtering apparatus, film formation in a high vacuum becomes possible . Also, since film formation with less damage by plasma becomes possible, even when the temperature of the substrate 660 is low , a film with high crystallinity can be formed. For example, even when the temperature of the substrate 660 is 10 °C or more and less than 100°C, a film with high crystallinity can be formed.

[0159] The configuration shown in FIG. 9(A) is different from the configuration shown in FIG. 8(A) in that the targets 600a and 600b are not parallel but are arranged facing each other in an inclined state (in a V shape). Therefore, for the description other than the target arrangement, refer to the description of FIG. 8(A). Also, the different poles of the magnet unit 630a and the magnet unit 630b face each other ​​ They are arranged in a sea urchin shape. The substrate holder 670 and the substrate 660 are arranged above the target-to-target region. By arranging the targets 600a and 600b as shown in FIG. 9(A), the ratio of sputtering particles reaching the substrate 660 increases, so the deposition rate can be increased.

[0160] FIG. 9(B) shows another example of a facing target type sputtering apparatus.

[0161] FIG. 9(B) is a schematic cross-sectional view of a film forming chamber in a facing target type sputtering apparatus. Unlike the film forming chamber shown in FIG. 8(A), target shields 622 and target shields 623 are provided. Also, it has a power supply 691 connected to the backing plates 610a and backing plates 610b. The substrate holder 670 is arranged above the target-to-target region. As a result, since the substrate 660 is not exposed to the high electric field region of the plasma 640, damage by the plasma 640 can be reduced.

[0162] Also, as shown in FIG. 9(B), the substrate holder 670 is arranged above the target-to-target region, but it may also be arranged below. Also, it may be arranged both below and above. By arranging the substrate holder 670 both below and above, two or more substrates can be film-formed simultaneously, so the productivity can be increased.

[0163] Also, as shown in FIG. 9(B), the target shields 622 and the target shields 6 23 are connected to GND. That is, the backing plates 610a and backing plates 610b to which the potential of the power supply 691 is applied, and the target shields to which GND is applied A plasma 640 is formed by the potential difference applied between the cathode 622 and the target shield 623.

[0164] In the opposed target type sputtering apparatus described above, since the plasma is confined in the magnetic field between the targets, plasma damage to the substrate can be reduced. Further, due to the inclination of the target, the incident angle of the sputtered particles on the substrate can be made shallow, so that the step coverage of the deposited film can be enhanced. Also, since film formation can be performed in a high vacuum, the concentration of impurities mixed into the film can be reduced.

[0165] Note that a parallel plate type sputtering apparatus or an ion beam sputtering apparatus may be applied to the film formation chamber.

[0166] <Film Forming Apparatus> Hereinafter, a film forming apparatus having a film formation chamber in which a sputtering target according to an aspect of the present invention can be installed will be described.

[0167] First, the configuration of a film forming apparatus with less impurity incorporation into the film during film formation or the like will be described with reference to FIGS. 10 and 11.

[0168] FIG. 10 schematically shows a top view of a single wafer type multi-chamber film forming apparatus 2700. The film forming apparatus 2700 includes an atmospheric side substrate supply chamber 2701 having a cassette port 2761 for accommodating a substrate and an alignment port 2762 for aligning the substrate, an atmospheric side substrate transfer chamber 2702 for transferring the substrate from the atmospheric side substrate supply chamber 2701, and a load lock chamber 2 for loading the substrate and switching the pressure inside the chamber from atmospheric pressure to reduced pressure or from reduced pressure to atmospheric pressure. 703a unloads the substrate and switches the pressure in the chamber from a reduced pressure to atmospheric pressure or from atmospheric pressure to a reduced pressure, and an unloading lock chamber 2703b, a transfer chamber 2704 that transfers the substrate in a vacuum, a substrate heating chamber 2705 that heats the substrate, and a film forming chamber 2706a, a film forming chamber 2706b, and a film forming chamber 2706c in which a target is disposed for film formation. Note that the film forming chambers 2706a, 2706b, and 2706c can refer to the configuration of the film forming chamber described above. Further, the atmospheric-side substrate transfer chamber 2702 is connected to the load lock chamber 2703a and the unloading lock chamber 2703b. The load lock chamber 2703a and the unloading lock chamber 2703b are connected to the transfer chamber 2704. The transfer chamber 2704 is connected to the substrate heating chamber 2705, the film forming chamber 2706a, the film forming chamber 2706b, and the film forming chamber 2706c. A gate valve 2764 is provided at the connection portion of each chamber. Except for the atmospheric-side substrate supply chamber 2701 and the atmospheric-side substrate transfer chamber 2702, each chamber can be independently maintained in a vacuum state. Further, the atmospheric-side substrate transfer chamber 2702 and the transfer chamber 2704 have a transfer robot 2763 and can transfer the substrate. In addition, it is preferable that the substrate heating chamber 2705 also serves as a plasma processing chamber. Since the film forming apparatus 2700 can transfer the substrate without exposing it to the atmosphere between processes, it is possible to suppress the adsorption of impurities to the substrate. Also, the order of film formation, heat treatment, etc. can be freely constructed. Note that the transfer chamber, the film forming chamber, the load lock chamber, the unloading lock chamber, and the substrate heating chamber

[0169]

[0170]

[0171] ​​​​​​​​​​​​​​is not limited to the above numbers, and an appropriate optimal number can be set according to the installation space and process conditions. It can be set.

[0172] Next, cross-sections corresponding to the dashed lines X1-X2, Y1-Y2, and Y2-Y3 of the film-forming apparatus 2700 shown in FIG. 10 are shown in FIG. 11. It is shown in FIG. 11.

[0173] FIG. 11(A) shows cross-sections of the substrate heating chamber 2705 and the transfer chamber 2704. The substrate heating chamber 2705 has a plurality of heating stages 2765 capable of accommodating substrates. Note that the substrate heating chamber 2705 is connected to a vacuum pump 2770 via a valve. As the vacuum pump 2770, for example, a dry pump and a mechanical booster pump can be used. Note that the substrate heating chamber 2705 is connected to a vacuum pump 2770 via a valve. As the vacuum pump 2770, for example, a dry pump and a mechanical booster pump can be used. As the vacuum pump 2770, for example, a dry pump and a mechanical booster pump can be used. etc. can be used.

[0174] In addition, as a heating mechanism that can be used in the substrate heating chamber 2705, for example, a heating mechanism that heats using a resistance heating element or the like may be used. Or, it may be a heating mechanism that heats by heat conduction or heat radiation from a medium such as a heated gas. For example, RTA (Rapid Thermal Anneal) such as GRTA (Ga s Rapid Thermal Anneal) and LRTA (Lamp Rapid Thermal Anneal) can be used. LRTA heats the object to be processed by radiation of light (electromagnetic wave) emitted from any lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp. GRTA performs heat treatment using a high-temperature gas. As the gas, an inert gas is used. In addition, as a heating mechanism that can be used in the substrate heating chamber 2705, for example, a heating mechanism that heats using a resistance heating element or the like may be used. Or, it may be a heating mechanism that heats by heat conduction or heat radiation from a medium such as a heated gas. For example, RTA (Rapid Thermal Anneal) such as GRTA (Ga s Rapid Thermal Anneal) and LRTA (Lamp Rapid Thermal Anneal) can be used. LRTA heats the object to be processed by radiation of light (electromagnetic wave) emitted from any lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp. GRTA performs heat treatment using a high-temperature gas. As the gas, an inert gas is used. thermal conduction or heat radiation from a medium such as a heated gas may also be used. For example, RTA (Rapid Thermal Anneal) such as GRTA (Ga s Rapid Thermal Anneal) and LRTA (Lamp Rapid Thermal Anneal) can be used. LRTA heats the object to be processed by radiation of light (electromagnetic wave) emitted from any lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp. GRTA performs heat treatment using a high-temperature gas. As the gas, an inert gas is used. Thermal Anneal) etc. Thermal Anneal) al) can be used. LRTA heats the object to be processed by radiation of light (electromagnetic wave) emitted from any lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp. GRTA performs heat treatment using a high-temperature gas. As the gas, an inert gas is used. from any lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp. GRTA performs heat treatment using a high-temperature gas. As the gas, an inert gas is used. GRTA performs heat treatment using a high-temperature gas. As the gas, an inert gas is used. As the gas, an inert gas is used.

[0175] Also, the substrate heating chamber 2705 is connected to the purifier 2781 via the mass flow controller 2780. Note that the mass flow controller 2780 and the purifier 2781 are provided in the number corresponding to the number of gas species, but only one is shown for ease of understanding. The gas introduced into the substrate heating chamber 2705 can be a gas with a dew point of -80°C or lower, preferably -100°C or lower. For example, oxygen gas, nitrogen gas, and noble gas (such as argon gas) can be used. The mass flow controller 2780 and the purifier 2781 are provided in the number corresponding to the number of gas species, but only one is shown for ease of understanding. The gas introduced into the substrate heating chamber 2705 can be a gas with a dew point of -80°C or lower, preferably -100°C or lower. For example, oxygen gas, nitrogen gas, and noble gas (such as argon gas) can be used. The mass flow controller 2780 and the purifier 2781 are provided in the number corresponding to the number of gas species, but only one is shown for ease of understanding. The gas introduced into the substrate heating chamber 2705 can be a gas with a dew point of -80°C or lower, preferably -100°C or lower. For example, oxygen gas, nitrogen gas, and noble gas (such as argon gas) can be used. The gas introduced into the substrate heating chamber 2705 can be a gas with a dew point of -80°C or lower, preferably -100°C or lower. For example, oxygen gas, nitrogen gas, and noble gas (such as argon gas) can be used. The gas introduced into the substrate heating chamber 2705 can be a gas with a dew point of -80°C or lower, preferably -100°C or lower. For example, oxygen gas, nitrogen gas, and noble gas (such as argon gas) can be used.

[0176] The transfer chamber 2704 has a transfer robot 2763. The transfer robot 2763 can transfer the substrate to each chamber. Also, the transfer chamber 2704 is connected to the vacuum pump 2770 and the cryopump 2771 via valves. With such a configuration, the transfer chamber 2704 is evacuated using the vacuum pump 2770 from atmospheric pressure to low vacuum or medium vacuum (about 0.1 to several hundred Pa), and the valves are switched to evacuate from medium vacuum to high vacuum or ultra-high vacuum The transfer chamber 2704 has a transfer robot 2763. The transfer robot 2763 can transfer the substrate to each chamber. Also, the transfer chamber 2704 is connected to the vacuum pump 2770 and the cryopump 2771 via valves. With such a configuration, the transfer chamber 2704 is evacuated using the vacuum pump 2770 from atmospheric pressure to low vacuum or medium vacuum (about 0.1 to several hundred Pa), and the valves are switched to evacuate from medium vacuum to high vacuum or ultra-high vacuum (0.1 Pa to 1×10 Pa) using the cryopump 2771. The transfer chamber 2704 has a transfer robot 2763. The transfer robot 2763 can transfer the substrate to each chamber. Also, the transfer chamber 2704 is connected to the vacuum pump 2770 and the cryopump 2771 via valves. With such a configuration, the transfer chamber 2704 is evacuated using the vacuum pump 2770 from atmospheric pressure to low vacuum or medium vacuum (about 0.1 to several hundred Pa), and the valves are switched to evacuate from medium vacuum to high vacuum or ultra-high vacuum (0.1 Pa to 1×10 -7 Pa) using the cryopump 2771.

[0177] Also, for example, two or more cryopumps 2771 may be connected in parallel to the transfer chamber 2704. With such a configuration, even if one cryopump is in regeneration, it is possible to evacuate using the remaining cryopumps. Note that the above-mentioned regeneration refers to a process of releasing the molecules (or atoms) trapped in the cryopump. Since the cryopump's evacuation ability decreases when too many molecules (or atoms) are trapped, regeneration is performed periodically. Also, for example, two or more cryopumps 2771 may be connected in parallel to the transfer chamber 2704. With such a configuration, even if one cryopump is in regeneration, it is possible to evacuate using the remaining cryopumps. Note that the above-mentioned regeneration refers to a process of releasing the molecules (or atoms) trapped in the cryopump. Since the cryopump's evacuation ability decreases when too many molecules (or atoms) are trapped, regeneration is performed periodically. Also, for example, two or more cryopumps 2771 may be connected in parallel to the transfer chamber 2704. With such a configuration, even if one cryopump is in regeneration, it is possible to evacuate using the remaining cryopumps. Note that the above-mentioned regeneration refers to a process of releasing the molecules (or atoms) trapped in the cryopump. Since the cryopump's evacuation ability decreases when too many molecules (or atoms) are trapped, regeneration is performed periodically. Also, for example, two or more cryopumps 2771 may be connected in parallel to the transfer chamber 2704. With such a configuration, even if one cryopump is in regeneration, it is possible to evacuate using the remaining cryopumps. Note that the above-mentioned regeneration refers to a process of releasing the molecules (or atoms) trapped in the cryopump. Since the cryopump's evacuation ability decreases when too many molecules (or atoms) are trapped, regeneration is performed periodically. Also, for example, two or more cryopumps 2771 may be connected in parallel to the transfer chamber 2704. With such a configuration, even if one cryopump is in regeneration, it is possible to evacuate using the remaining cryopumps. Note that the above-mentioned regeneration refers to a process of releasing the molecules (or atoms) trapped in the cryopump. Since the cryopump's evacuation ability decreases when too many molecules (or atoms) are trapped, regeneration is performed periodically. Also, for example, two or more cryopumps 2771 may be connected in parallel to the transfer chamber 2704. With such a configuration, even if one cryopump is in regeneration, it is possible to evacuate using the remaining cryopumps. Note that the above-mentioned regeneration refers to a process of releasing the molecules (or atoms) trapped in the cryopump. Since the cryopump's evacuation ability decreases when too many molecules (or atoms) are trapped, regeneration is performed periodically.

[0178] ​​FIG. 11(B) shows the cross-section of the film forming chamber 2706b, the transfer chamber 2704, and the load lock chamber 2703a. It shows a cross-section.

[0179] Here, the details of the film forming chamber (sputtering chamber) will be described with reference to FIG. 11(B). The film forming chamber 2706b shown in FIG. 11(B) includes a target 2766a, a target 2766 b, a target shield 2767a, a target shield 2767b, a magnet unit 2790a, a magnet unit 2790b, a substrate holder 2768, and a power supply 2791. Although not shown, the targets 2766a and 2766 b are fixed to the target holders via backing plates respectively. Also, the power supply 2791 is electrically connected to the targets 2766a and 2766 b. The magnet units 2790a and 2790b are respectively arranged at the back of the targets 2766a and 2766 b. The target shields 2767a and 2767b are arranged to surround the ends of the targets 2766a and 2766 b respectively. Here, a substrate 2769 is supported by the substrate holder 2768. The substrate holder 2768 is fixed to the film forming chamber 2706b via a variable member 278 4. The substrate holder 27 68 can be moved by the variable member 2784. The substrate holder 2768 is arranged above the region between the targets 2766a and 2766 b (also referred to as the inter-target region). For example, by arranging the substrate holder 2768 supporting the substrate 2769 above the inter-target region, the damage by plasma can be reduced. Also, the substrate holder 2768 is arranged above the region between the targets 2766a and 2766 b. For example, by arranging the substrate holder 2768 supporting the substrate 2769 above the inter-target region, the damage by plasma can be reduced. Also, the substrate holder 2768 is arranged above the region between the targets 2766a and 2766 (also referred to as the inter-target region). For example, by arranging the substrate holder 2768 supporting the substrate 2769 above the inter-target region, the damage by plasma can be reduced. Also, the substrate holder 2768 supporting the substrate 2769 is arranged above the inter-target region, so that the damage by plasma can be reduced. Also, the substrate holder 2768 can reduce the damage caused by plasma. Also, the substrate holder 2768 Although not shown, it may include a substrate holding mechanism for holding the substrate 2769, a heater for heating the substrate 2769 from the back surface, etc. It may be provided with a heater or the like that heats from the back surface.

[0180] Also, as shown in Fig. 11(B), the substrate holder 2768 is disposed above the target - to - target region, but it may be disposed below. Further, it may be disposed both below and above. By disposing the substrate holder 2768 both below and above, two or more substrates can be film - formed simultaneously, so that productivity can be improved. By arranging the substrate holder 2768 on the lower side and the upper side, two or more substrates can be simultaneously film - formed, so that productivity can be enhanced.

[0181] Also, the target shield 2767 can suppress the deposition of particles sputtered from the target 2766 in an unnecessary region. The target shield 2767 is preferably processed so that the deposited sputter particles do not peel off. For example, a blasting process for increasing the surface roughness, or providing irregularities on the surface of the target shield 2767 may be employed. It is desirable to process the target shield 2767 so that the accumulated sputter particles do not peel off. For example, a blasting process that increases the surface roughness, or providing irregularities on the surface of the target shield 2767 may be acceptable. good.

[0182] Also, the film - forming chamber 2706b is connected to the mass - flow controller 27 80 via the gas heating mechanism 2782, and the gas heating mechanism 2782 is connected to the purification machine 2781 via the mass - flow controller 2780. The gas heating mechanism 2782 can heat the gas introduced into the film - forming chamber 2706b to 40°C or higher and 400°C or lower. Note that the gas heating mechanism 2782, the mass - flow controller 2780, and the purification machine 2781 are provided in the number corresponding to the number of gas species, but only one is shown for ease of understanding. The gas introduced into the film - forming chamber 2706b can be a gas having a dew point of - 80°C or lower, preferably - 100°C or lower. For example, oxygen gas, nitrogen gas, and rare gas (such as argon gas) can be used. is - 80°C or lower, preferably - 100°C or lower, and for example, oxygen gas, nitrogen gas, and rare gas (such as argon gas) can be used. gas, nitrogen gas, and rare gas (such as argon gas) are used.

[0183] In addition, when a refiner is provided immediately before the gas inlet, the arrangement from the refiner to the deposition chamber 2706b is The length of the pipe is 10m or less, preferably 5m or less, and more preferably 1m or less. By limiting the length to 10m or less, 5m or less, or 1m or less, the effects of gas released from the piping can be reduced. The reduction can be achieved depending on the length. In addition, the gas piping is It is recommended to use metal piping with the inside coated with chrome or the like. The above piping is made of, for example, SUS3 Compared to 16L-EP piping, the amount of gas containing impurities released is smaller, and the amount of impurities that enter the gas is reduced. In addition, the pipe joints are equipped with high-performance ultra-small metal gasket joints (UPG joints). In addition, by constructing the piping entirely from metal, it is possible to reduce the cost compared to using resin, etc. This is preferable because it can reduce the effects of released gas and external leakage.

[0184] The deposition chamber 2706b is connected to a turbo molecular pump 2772 and a vacuum pump 2773 via a valve. It is connected to 2770.

[0185] Further, the film formation chamber 2706b is provided with a cryotrap 2751.

[0186] Cryotrap 2751 adsorbs molecules (or atoms) with relatively high melting points, such as water. The turbomolecular pump 2772 is a mechanism that can pump large molecules (or atoms). ) and requires little maintenance, making it highly productive. The pumping capacity for water is low. Therefore, in order to increase the pumping capacity for water, etc., a cryotrap is used. The cryotrap 2751 is connected to the deposition chamber 2706b. The temperature of the refrigerator is set to 100 K or less, preferably 80 K or less. If the 751 has multiple refrigerators, changing the temperature of each refrigerator will allow for more efficient exhaust. For example, the temperature of the first stage refrigerator is set to 100K or less, and the second stage refrigerator is set to 100K or less. The temperature of the first refrigerator should be set to 20K or less. In some cases, a higher vacuum can be achieved by using a sublimation pump. In addition, by using an ion pump instead of a cryopump or turbomolecular pump, In some cases, a high vacuum can be achieved.

[0187] The method of exhausting the film forming chamber 2706b is not limited to this, and may be the same as that of the transport chamber 2704. The same configuration as the evacuation method (the evacuation method of a cryopump and a vacuum pump) may be used. The exhaust method for the transfer chamber 2704 is the same as that for the film forming chamber 2706b (a turbo molecular pump and a It is also possible to use an empty pump as an exhaust method.

[0188] In addition, the back pressure ( It is preferable that the total pressure and the partial pressure of each gas molecule (atom) are as follows. Since there is a possibility that impurities may be mixed into the film being formed, the back pressure of the film forming chamber 2706b, etc. It is also necessary to pay attention to the partial pressure of each gas molecule (atom).

[0189] The back pressure (total pressure) of each of the above mentioned chambers is 1×10 -4 Pa or less, preferably 3×10 -5 Pa or less, and more preferably 1×10 -5 The mass-to-charge ratio (m / z The partial pressure of a gas molecule (atom) with a mass of 18 is 3 × 10 -5 Pa or less, preferably 1×10 -5Below Pa, more preferably 3×10 -6 Below Pa. Also, the m / z of the gas molecule (atom) with 28 is 3×10 -5 Below Pa, preferably 1×1 0 -5 Below Pa, more preferably 3×10 -6 Below Pa. Also, the m / z of the gas molecule (atom) with 44 is 3×10 -5 Below Pa, preferably 1× 10 -5 Below Pa, more preferably 3×10 -6 Below Pa.

[0190] Note that the total pressure and partial pressure in the vacuum chamber can be measured using a mass spectrometer . For example, the quadrupole mass spectrometer (also referred to as Q-mass) Qul ee CGM-051 manufactured by ULVAC, Inc. may be used.

[0191] Also, the above-described transfer chamber 2704, substrate heating chamber 2705, and film formation chamber 2706b are desirably configured to have little external leakage or internal leakage.

[0192] For example, the leak rates of the above-described transfer chamber 2704, substrate heating chamber 2705, and film formation chamber 2706b are 3×10 -6 Pa·m 3 / s or less, preferably 1×10 -6 Pa·m 3 / s or less. Also, the leak rate of the gas molecule (atom) with m / z of 18 is 1×10 -7 Pa·m 3 / s or less, preferably 3×10 -8 Pa·m 3 / s or less. Also, the leak rate of the gas molecule (atom) with m / z of 28 is 1×10 -5 Pa·m 3 / s or less, preferred Or 1×10 -6 Pa·m 3 / s or less. Also, gas molecules with m / z of 44 (atomic child) leak rate is 3×10 -6 Pa·m 3 / s or less, preferably 1×10 -6 Pa. m 3 / s or less.

[0193] The leak rate was calculated from the total and partial pressures measured using the mass spectrometer mentioned above. It can be derived.

[0194] The leak rate depends on external and internal leaks. External leaks occur due to tiny holes or seals. An internal leak is when gas flows into the vacuum system from outside due to a valve failure or other reasons. This is caused by leakage from partitions such as valves and gas released from internal components. In order to keep the above values ​​or less, measures must be taken to prevent both external and internal leaks. There is.

[0195] For example, the opening and closing part of the deposition chamber 2706b may be sealed with a metal gasket. Sketches are metals coated with iron fluoride, aluminum oxide, or chromium oxide. It is recommended to use a metal gasket. Metal gaskets have a higher adhesion than O-rings and reduce external leakage. Also, metals coated with iron fluoride, aluminum oxide, chromium oxide, etc. By using a passivation material, gas emissions containing impurities released from the metal gasket are suppressed. This makes it possible to reduce internal leakage.

[0196] In addition, the film forming apparatus 2700 is made of aluminum, which emits less gas containing impurities. Use um, chromium, titanium, zirconium, nickel or vanadium. Also, the aforementioned member may be coated with an alloy containing iron, chromium and nickel and used. Alloys containing iron, chromium and nickel are rigid, heat-resistant and suitable for processing. Here if the surface unevenness of the member is reduced by polishing or the like to reduce the surface area, the released gas can be reduced.

[0197] Or, the member of the aforementioned film forming apparatus 2700 may be coated with iron fluoride, aluminum oxide, chromium oxide, etc.

[0198] The members of the film forming apparatus 2700 are preferably composed of only metal as much as possible. For example, even when installing a viewing window composed of quartz or the like, the surface is thinly coated with iron fluoride, acid aluminum oxide, chromium oxide, etc. to suppress the released gas.

[0199] The adsorbates present in the film forming chamber do not affect the pressure in the film forming chamber because they are adsorbed on the inner wall or the like, but they cause gas release when the film forming chamber is evacuated. Therefore, although there is no relation between the leak rate and the evacuation speed, it is important to use a pump with a high evacuation ability to desorb the adsorbates present in the film forming chamber as much as possible and evacuate in advance. In addition, in order to promote the desorption of the adsorbates, the film forming chamber may be baked. By baking, the desorption rate of the adsorbates can be increased by about 10 times . Baking may be performed at 100 °C or higher and 450 °C or lower. At this time , when removing the adsorbates while introducing an inert gas into the film forming chamber, the desorption rate of substances such as water that are difficult to desorb by simply evacuating can be further increased. In addition, by heating the introduced inert gas to about the same temperature as the baking temperature, the desorption rate of the adsorbates can be further increased . . It is preferable to use a noble gas as the inert gas here. Also, depending on the type of film to be formed, oxygen or the like may be used instead of the inert gas. For example, when forming an oxide film, it may be preferable to use oxygen as the main component. Note that baking is preferably performed using a lamp.

[0200] Alternatively, it is preferable to increase the pressure in the film formation chamber by introducing an inert gas such as heated noble gas or oxygen, etc., and then perform a process of evacuating the film formation chamber again after a certain period of time. By introducing the heated gas, the adsorbed substances in the film formation chamber can be desorbed, and the impurities present in the film formation chamber can be reduced. Note that this process is effectively repeated in the range of 2 to 30 times, preferably 5 to 15 times. Specifically, by introducing an inert gas or oxygen etc. whose temperature is 40°C or higher and 400°C or lower, preferably 50°C or higher and 200°C or lower, the pressure in the film formation chamber is set to 0.1 Pa or higher and 10 kPa or lower, preferably 1 Pa or higher and 1 kPa or lower, more preferably 5 Pa or higher and 100 Pa or lower, and the period for maintaining the pressure is 1 minute or longer and 300 minutes or shorter, preferably 5 minutes or longer and 120 minutes or shorter. Then, the film formation chamber is evacuated for a period of 5 minutes or longer and 300 minutes or shorter, preferably 10 minutes or longer and 120 minutes or shorter.

[0201] Also, the desorption rate of the adsorbed substances can be further increased by performing dummy film formation. Dummy film formation refers to depositing a film on a dummy substrate and the inner wall of the film formation chamber by a sputtering method or the like for the dummy substrate, and confining the impurities in the film formation chamber and the adsorbed substances on the inner wall of the film formation chamber in the film. The dummy substrate is preferably a substrate with little outgassing. Dummy film formation ​​​​By performing this, the impurity concentration in the film to be formed later can be reduced. Note that dummy The film formation may be performed simultaneously with the baking.

[0202] Next, the details of the transfer chamber 2704 shown in FIG. 11(B), and the load lock chamber 2703a, and FIG. 11 (C) will be described below for the details of the atmospheric-side substrate transfer chamber 2702 and the atmospheric-side substrate supply chamber 2701. Note that FIG. 11(C) shows a cross-section of the atmospheric-side substrate transfer chamber 2702 and the atmospheric-side substrate supply chamber 2701. For the transfer chamber 2704 shown in FIG. 11(B), refer to the description of the transfer chamber 2704 shown in FIG. 11(A).

[0203] Regarding the transfer chamber 2704 shown in FIG. 11(B), refer to the description of the transfer chamber 2704 shown in FIG. 11(A). for reference.

[0204] The load lock chamber 2703a has a substrate transfer stage 2752. The load lock chamber 2703a raises the pressure from a reduced pressure state to the atmosphere, and when the pressure in the load lock chamber 2703a reaches atmospheric pressure, the transfer robot 276 3 provided in the atmospheric-side substrate transfer chamber 2702 receives the substrate on the substrate transfer stage 2752. Then, the load lock chamber 270 3a is evacuated and brought into a reduced pressure state, and then the transfer robot 2763 provided in the transfer chamber 2704 receives the substrate from the substrate transfer stage 2752.

[0205] Also, the load lock chamber 2703a is connected to a vacuum pump 2770 and a cryo pump 2771 via a valve. The connection method of the exhaust systems of the vacuum pump 2770 and the cryopump 277 1 can be connected by referring to the connection method of the transfer chamber 2704, so the description here is omitted. Note that the unload lock chamber 2703b shown in FIG. 10 can have the same configuration as the load lock chamber 2703a. ​​​

[0206] The atmospheric-side substrate transfer chamber 2702 has a transfer robot 2763. The transfer robot 2763 can transfer substrates between the cassette port 2761 and the load lock chamber 2703a. Also, above the atmospheric-side substrate transfer chamber 2702 and the atmospheric-side substrate supply chamber 2701 a mechanism for cleaning dust or particles such as a HEPA filter (High Efficiency Particulate Air r Filter) may be provided. .

[0207] The atmospheric-side substrate supply chamber 2701 has a plurality of cassette ports 2761. The cassette ports 2761 can accommodate a plurality of substrates.

[0208] The target should have a surface temperature of 100°C or lower, preferably 50°C or lower, and more preferably room temperature level (typically 25°C). In a sputtering apparatus for a large-area substrate, a large-area target is often used. However, it is difficult to fabricate a target of a size corresponding to a large area without joints. In reality, a plurality of targets are arranged as closely as possible to form a large shape, but inevitably a slight gap is generated. From such a slight gap, when the surface temperature of the target increases, zinc or the like volatilizes, and the gap may gradually widen. When the gap widens, the backing plate or the metal of the bonding material used for bonding the backing plate and the target may be sputtered which becomes a factor increasing the impurity concentration. Therefore, it is preferable that the target is sufficiently cooled. .

[0209] ​​​​​​​Specifically, a metal having high electrical conductivity and high heat dissipation properties (e.g., In addition, a water channel is formed in the backing plate, and a sufficient amount of By flowing cooling water, the target can be cooled efficiently.

[0210] In addition, when the target contains zinc, the plasma damage is reduced by forming the film in an oxygen gas atmosphere. This reduces the image and makes it possible to obtain an oxide in which zinc is less likely to volatilize.

[0211] By using the above-mentioned film formation apparatus, the hydrogen concentration can be measured by secondary ion mass spectrometry (SIMS:Se In condary ion mass spectrometry, 2 0 atoms / cm 3 Less than or equal to 5×10 19 atoms / cm 3 The following is more preferred: Or 1×10 19 atoms / cm 3 Less than 5×10, more preferably 18 atoms / cm 3 An oxide semiconductor film can be formed as follows.

[0212] In addition, the nitrogen concentration was 5×10 19 atoms / cm 3 Less than, preferably is 1×10 19 atoms / cm 3 Less than or equal to 5×10 18 atoms / cm 3 Less than 1×10, more preferably 18 atoms / cm 3 The oxide semiconductor It is possible to form a membrane.

[0213] In addition, an oxide semiconductor can be formed into a film when the carbon concentration is less than 5×10 19 atoms / cm 3 , preferably less than 5×10 18 atoms / cm 3 , more preferably less than 1×10 18 atoms / cm 3 , even more preferably less than 5×10 17 atoms / cm 3 .

[0214] An oxide with few impurities and oxygen deficiencies is an oxide with a low carrier density. Specifically, the carrier density is less than 8×10 11 / cm 3 , preferably less than 1×10 11 / cm 3 , and even more preferably less than 1×10 10 / cm 3 , and can be -9 1×10 3 / cm or more. Such an oxide semiconductor is called a high-purity intrinsic or substantially high-purity intrinsic oxide semiconductor. CAAC-OS has a low impurity concentration and a low defect level density. That is, it can be said that it is an oxide having stable properties.

[0215] In addition, an oxide semiconductor can be formed into a film when the emission amounts of gas molecules (atoms) with m / z of 2 (such as hydrogen molecules), gas molecules (atoms) with m / z of 18, gas molecules (atoms) with m / z of 28, and gas molecules (atoms) with m / z of 44 measured by TDS are each less than 1×10 , preferably less than 1×1 0 19 individuals / cm 3 , and more preferably less than 1×1 0 18 individuals / cm 3 .

[0216] ​​​By using the above-described film forming apparatus, it is possible to suppress the incorporation of impurities into the oxide. Furthermore, by forming a film in contact with the oxide using the above film forming apparatus, it is possible to suppress the incorporation of impurities from the film in contact with the oxide into the oxide .

[0217] As described above, the configuration shown in this embodiment can be appropriately combined with the configurations shown in other embodiments or other examples and used.

[0218] (Embodiment 3) In this embodiment, one form of the semiconductor device will be described with reference to FIGS. 12 to 22

[0219] <Transistor Structure 1> Hereinafter, an example of a transistor according to one aspect of the present invention will be described. FIGS. 12(A), FIG. 12(B), and FIG. 12(C) are top views and cross-sectional views of a transistor according to one aspect of the present invention . FIG. 12(A) is a top view, FIG. 12(B) is a cross-sectional view corresponding to the dashed line X1-X2 shown in FIG. 12(A), and FIG. 12(C) is a cross-sectional view corresponding to the dashed line Y1-Y2 . Note that in the top view of FIG. 12(A), some elements are omitted for clarity of the drawing .

[0220] The transistor 200 includes conductors 205 (conductor 205a and conductor 205b) that function as gate electrodes, and conductor 260, insulators 220 that function as a gate insulating layer, insulators 222, insulators 224, and insulator 250, an oxide 230 (oxide 230a, oxide 230b, and oxide 230c) in which a channel is formed, a conductor 240a that functions as one of a source or a drain, a conductor 240b that functions as the other of the source or the drain, an insulator 280 having excess oxygen, and a barrier property . One of the conductors 240a functions as either a source or a drain, and the other conductor 240b functions as the other of the source or the drain . It has an insulator 282.

[0221] Also, the oxide 230 has an oxide 230a, an oxide 230b on the oxide 230a, and an oxide 230c on the oxide 230b. When the transistor 200 is turned on, current mainly flows through the oxide 230b (a channel is formed). On the other hand, although current may flow in the vicinity of the interface between the oxide 230a and the oxide 230c (there are cases where it becomes a mixed region), other regions may function as insulators.

[0222] Also, as shown in FIG. 12, the oxide 230c is preferably provided so as to cover the side surfaces of the oxide 230a and the oxide 230b. By interposing the oxide 230c between the insulator 280 and the oxide 230b having a region where a channel is formed, impurities such as hydrogen, water, and halogen can be suppressed from diffusing from the insulator 280 to the oxide 230b.

[0223] The conductor 205 is a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, scandium, or a metal nitride film having the above-mentioned elements as components (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film), etc. In particular, metal nitride films such as tantalum nitride film have barrier properties against hydrogen or oxygen and are difficult to oxidize (have high oxidation resistance), so they are preferred. Or, Conductive materials such as um tin oxide, indium zinc oxide, and indium tin oxide added with silicon oxide can also be applied. It is also possible to apply a conductive material.

[0224] For example, as the conductor 205a, a conductor having a barrier property against hydrogen, such as tantalum nitride, etc. can be used, and as the conductor 205b, highly conductive tungsten can be laminated. By using this combination, diffusion of oxygen into the oxide 230 can be suppressed while maintaining the conductivity as a wiring. In FIG. 12, a two-layer structure of the conductor 205a and the conductor 2 05b is shown, but it is not limited to this configuration, and it may be a single layer or a laminated structure of three or more layers. For example, between a conductor having a barrier property and a highly conductive conductor, a conductor having a barrier property, and a conductor having high adhesion to the highly conductive conductor may be formed.

[0225] The insulator 224 is preferably an oxygen-containing insulator such as a silicon oxide film or a silicon oxynitride film. In particular, as the insulator 224, it is preferable to use an insulator containing excess oxygen (containing more oxygen than the stoichiometric composition). By providing such an insulator containing excess oxygen in contact with the oxide 230 constituting the transistor 200, oxygen vacancies in the oxide 230 can be compensated.

[0226] Further, when the insulator 224 has an excess oxygen region, the insulator 222 preferably has a barrier property against oxygen, hydrogen, and water. Since the insulator 222 has a barrier property against oxygen, oxygen in the excess oxygen region can be efficiently supplied to the oxide 230 without diffusing to the transistor 300 side. Also, when the conductor 205 has what the insulator 224 has It is possible to suppress the reaction with oxygen in the excessive oxygen region formed.

[0227] The insulator 222 is preferably a single layer or a laminate of insulators such as silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3) or (Ba,Sr)TiO3 ( BST), etc. In particular, it is preferable to use an insulating film that is barrier against oxygen and hydrogen, such as aluminum oxide and hafnium oxide. When formed using such materials, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside.

[0228] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide may be added to these insulators. Or these insulators may be nitrided. The above insulators may be used by laminating silicon oxide, silicon oxynitride or silicon nitride thereon.

[0229] Note that the insulator 220, the insulator 222, and the insulator 224 may have a laminated structure of two or more layers. In that case, it is not limited to a laminated structure made of the same material, and a laminated structure made of different materials may also be used.

[0230] Also, by having the insulator 222 containing a high-k material between the insulator 220 and the insulator 224, the insulator 222 can capture electrons under specific conditions and increase the threshold voltage. That is, the insulator 222 may be negatively charged.

[0231] For example, silicon oxide is used for the insulators 220 and 224, and for the insulator 222, a material with many electron trapping levels such as hafnium oxide, aluminum oxide, or tantalum oxide is used. When the temperature is higher than the operating temperature or storage temperature of the semiconductor device (for example, 125°C or higher and 450°C or lower, typically 150°C or higher and 300°C or lower), the potential of the conductor 205 is maintained at a level higher than the potential of the source electrode or drain electrode for 10 milliseconds or more, typically 1 minute or more. In this way, electrons move from the oxide constituting the transistor 200 towards the conductor 205. At this time, some of the moving electrons are trapped at the electron trapping levels of the insulator 222.

[0232] For the transistor in which the necessary amount of electrons is trapped at the electron trapping levels of the insulator 222, the threshold voltage shifts to the positive side. Note that the amount of electrons trapped can be controlled by controlling the voltage of the conductor 205, and accordingly, the threshold voltage can be controlled. With this configuration, the transistor 200 becomes a normally-off type transistor that is in a non-conductive state (also referred to as an off state) even when the gate voltage is 0V.

[0233] Also, the process of trapping electrons can be performed during the manufacturing process of the transistor. For example, it can be performed at any stage before factory shipment, such as after forming the conductor connected to the source conductor or drain conductor of the transistor, or after the completion of the previous process (wafer processing), or after the wafer dicing process, or after packaging.

[0234] Also, by appropriately adjusting the film thicknesses of the insulators 220, 222, and 224, The threshold voltage can be controlled. For example, since the total film thickness of insulator 220, insulator 222, and insulator 224 is reduced, the voltage from conductor 205 is efficiently applied, so that a transistor with low power consumption can be provided. The total film thickness of insulator 220, insulator 222, and insulator 224 is preferably 65 nm or less, more preferably 20 nm or less. Accordingly, a transistor with a small leakage current in the non-conducting state can be provided. Also, a transistor with stable electrical characteristics can be provided. Or, a transistor with a large on-current can be provided. Or, a transistor with a small subthreshold swing value can be provided. Or, a highly reliable transistor can be provided. Oxide 230a, oxide 230b, and oxide 230c are formed of a metal oxide such as In-M-Zn oxide (M is Al, Ga, Y, or Sn). Also, as oxide 230, In-Ga oxide or In-Zn oxide may be used. Note that, as the oxide used for oxide 230b, the oxide semiconductor described in the previous embodiment can be used.

[0235]

[0236]

[0237]

[0238] Also, since oxide 230a and oxide 230b, and oxide 230b and oxide 230c have (as the main component) an element common to each other other than oxygen, a mixed layer with a low defect level density can be formed. For example, when oxide 230b is In-Ga-Zn oxide, as oxide 230a and oxide 230c, In-Ga-Zn oxide, Ga-Zn oxide, gallium oxide, etc. ​It may be used.

[0239] At this time, the main path of the carrier becomes the oxide 230b. The defect level density at the interface between the oxide 230a and the oxide 23 0b, and at the interface between the oxide 230b and the oxide 230c can be lowered. Therefore, the influence of interface scattering on carrier conduction is small, and a high on-current can be obtained.

[0240] When electrons are trapped in the trap level, the trapped electrons behave like fixed charges, so the threshold voltage of the transistor shifts in the positive direction. By providing the oxide 230a and the acid oxide 230c, the trap level can be moved farther away from the oxide 230b. With this configuration, it is possible to prevent the threshold voltage of the transistor from shifting in the positive direction.

[0241] The oxide 230a and the oxide 230c use a material with a sufficiently low conductivity compared to the oxide 230b. At this time, the oxide 230b, the interface between the oxide 230b and the oxide 230a, and the interface between the oxide 230b and the oxide 230c mainly function as the channel region.

[0242] For example, when using an oxide in which the region A2 and the region B2 in FIG. 5 form a composite in the oxide 230b, for the oxide 230a and the oxide 230c, it is preferable to use an oxide in which [M] / [In] is 1 or more, preferably 2 or more. Also, as the oxide 230c, it is suitable to use an oxide in which [M] / ([Zn]+[In]) is 1 or more so that sufficiently high insulation can be obtained.

[0243] The insulator 250 can be used in a single layer or in a laminate of insulators such as, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3) or (Ba,Sr)TiO3 ( (BST). Alternatively, these insulators can be added with, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide , titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide. Alternatively, these insulators can be nitrided. Silicon oxide, silicon oxynitride or silicon nitride may be laminated on the above insulators for use. For example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide , titanium oxide, tungsten oxide, yttrium oxide, zirconium oxide may be added. Or these insulators may be nitrided. Silicon oxide, silicon oxynitride or silicon nitride may be laminated on the above insulators for use. Also, it is preferable to use an oxide insulator containing more oxygen than the stoichiometric composition for the insulator 250, similar to the insulator 224. By providing such an insulator containing excess oxygen in contact with the oxide 230, it is possible to reduce the oxygen deficiency in the oxide 230. Also, the insulator 250 can use an insulating film that is barrier to oxygen and hydrogen, such as aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride, silicon nitride. When formed using such a material, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside.

[0244] In addition, the insulator 250 can have a lamination similar to that of the insulator 220, the insulator 222, and the insulator 224. By using an oxide insulator containing more oxygen than the stoichiometric composition for the insulator 250, similar to the insulator 224, it is possible to reduce the oxygen deficiency in the oxide 230 by providing such an insulator containing excess oxygen in contact with the oxide 230. Also, the insulator 250 can use an insulating film that is barrier to oxygen and hydrogen, such as aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride, silicon nitride. When formed using such a material, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside. Note that the insulator 250 can have a lamination similar to that of the insulator 220, the insulator 222, and the insulator 224.

[0245] In addition, the insulator 250 can use an insulating film that is barrier to oxygen and hydrogen, such as aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride, silicon nitride. When formed using such a material, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside. For the insulator 250, an insulating film that is barrier to oxygen and hydrogen, such as aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, yttrium oxide, yttrium oxynitride, hafnium oxide, hafnium oxynitride, silicon nitride, can be used. When formed using such a material, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside. In addition, the insulator 250 can have a lamination similar to that of the insulator 220, the insulator 222, and the insulator 224.

[0246] Note that the insulator 250 can have a lamination similar to that of the insulator 220, the insulator 222, and the insulator 224. It may have a structure. The insulator 250 has captured the amount of electrons necessary for the electron trapping level. By having an insulator, the transistor 200 can shift the threshold voltage to the positive side. By having such a configuration, the transistor 200 becomes a normally-off type transistor that is in a non-conducting state (also referred to as an off state) even when the gate voltage is 0V.

[0247] Also, in the transistor shown in FIG. 12, a barrier film may be provided between the oxide 230 and the conductor 260 in addition to the insulator 250. Alternatively, an oxide 230c having barrier properties may be used.

[0248] For example, by providing an insulating film containing excess oxygen in contact with the oxide 230 and further wrapping it with a barrier film, the oxide can be brought into a state that substantially matches the stoichiometric composition, or a supersaturated state with more oxygen than the stoichiometric composition. Also, the intrusion of impurities such as hydrogen into the oxide 230 can be prevented.

[0249] One of the conductor 240a and the conductor 240b functions as a source electrode, and the other functions as a drain electrode.

[0250] The conductor 240a and the conductor 240b can be made of a metal such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or an alloy having this as a main component. In particular, a metal nitride film such as a tantalum nitride film has barrier properties against hydrogen or oxygen and high oxidation resistance, so it is preferable.

[0251] In addition, although a single-layer structure is shown in the figure, a laminated structure of two or more layers may also be used. For example, a titanium nitride film and a tungsten film may be laminated. Also, a titanium film and an aluminum film may be laminated. In addition, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, or a two-layer structure in which a copper film is laminated on a tungsten film may also be used. In addition, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, or a two-layer structure in which a copper film is laminated on a tungsten film may also be used. In addition, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, or a two-layer structure in which a copper film is laminated on a tungsten film may also be used. In addition, a two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, or a two-layer structure in which a copper film is laminated on a tungsten film may also be used.

[0252] In addition, a titanium film or a titanium nitride film, an aluminum film or a copper film is laminated on the titanium film or the titanium nitride film, and a titanium film or a titanium nitride film is further formed thereon. In addition, a titanium film or a titanium nitride film, an aluminum film or a copper film is laminated on the titanium film or the titanium nitride film, and a titanium film or a titanium nitride film is further formed thereon. In addition, a three-layer structure in which a molybdenum film or a molybdenum nitride film, an aluminum film or a copper film is laminated on the molybdenum film or the molybdenum nitride film, and a molybdenum film or a molybdenum nitride film is further formed thereon. In addition, a three-layer structure in which a molybdenum film or a molybdenum nitride film, an aluminum film or a copper film is laminated on the molybdenum film or the molybdenum nitride film, and a molybdenum film or a molybdenum nitride film is further formed thereon. In addition, a three-layer structure in which a molybdenum film or a molybdenum nitride film, an aluminum film or a copper film is laminated on the molybdenum film or the molybdenum nitride film, and a molybdenum film or a molybdenum nitride film is further formed thereon. A transparent conductive material containing indium oxide, tin oxide, or zinc oxide may also be used. In addition, a three-layer structure in which a molybdenum film or a molybdenum nitride film, an aluminum film or a copper film is laminated on the molybdenum film or the molybdenum nitride film, and a molybdenum film or a molybdenum nitride film is further formed thereon. A transparent conductive material containing indium oxide, tin oxide, or zinc oxide may also be used.

[0253] In addition, the conductor 260 having a function as a gate electrode may be formed using, for example, a metal selected from aluminum, chromium, copper, tantalum, titanium, molybdenum, tungsten, or an alloy containing the above-described metals as components, or an alloy combining the above-described metals. In addition, the conductor 260 having a function as a gate electrode may be formed using, for example, a metal selected from aluminum, chromium, copper, tantalum, titanium, molybdenum, tungsten, or an alloy containing the above-described metals as components, or an alloy combining the above-described metals. In addition, the conductor 260 having a function as a gate electrode may be formed using, for example, a metal selected from aluminum, chromium, copper, tantalum, titanium, molybdenum, tungsten, or an alloy containing the above-described metals as components, or an alloy combining the above-described metals. In particular, a metal nitride film such as a tantalum nitride film has a barrier property against hydrogen or oxygen and high oxidation resistance, so it is preferable. Also, a metal selected from either one or a plurality of manganese and zirconium may be used. In addition, a semiconductor typified by polycrystalline silicon doped with an impurity element such as phosphorus, or a silicide such as nickel silicide may also be used. In particular, a metal nitride film such as a tantalum nitride film has a barrier property against hydrogen or oxygen and high oxidation resistance, so it is preferable. Also, a metal selected from either one or a plurality of manganese and zirconium may be used. In addition, a semiconductor typified by polycrystalline silicon doped with an impurity element such as phosphorus, or a silicide such as nickel silicide may also be used. In particular, a metal nitride film such as a tantalum nitride film has a barrier property against hydrogen or oxygen and high oxidation resistance, so it is preferable. Also, a metal selected from either one or a plurality of manganese and zirconium may be used. In addition, a semiconductor typified by polycrystalline silicon doped with an impurity element such as phosphorus, or a silicide such as nickel silicide may also be used. In particular, a metal nitride film such as a tantalum nitride film has a barrier property against hydrogen or oxygen and high oxidation resistance, so it is preferable. Also, a metal selected from either one or a plurality of manganese and zirconium may be used. In addition, a semiconductor typified by polycrystalline silicon doped with an impurity element such as phosphorus, or a silicide such as nickel silicide may also be used. Yes. Also, although a single-layer structure is shown in the figure, a laminated structure of two or more layers may also be used.

[0254] For example, a two-layer structure in which a titanium film is laminated on aluminum may be used. Also, a two-layer structure in which a titanium film is laminated on a titanium nitride film, a two-layer structure in which a tungsten film is laminated on a titanium nitride film, a two-layer structure in which a tungsten film is laminated on a tantalum nitride film or a tungsten nitride film may be used. Yes.

[0255] Also, there is a three-layer structure in which a titanium film, an aluminum film is laminated on the titanium film, and a titanium film is further formed thereon. Also, an alloy film or a nitride film in which aluminum is combined with one or more metals selected from titanium, tantalum, tungsten, molybdenum, chromium, neodymium, and scandium may be used. Yes. Yes.

[0256] Also, the conductor 260 may be an indium tin oxide, an indium oxide containing tungsten oxide, an indium zinc oxide containing tungsten oxide, an indium oxide containing titanium oxide, an indium tin oxide containing titanium oxide, an indium zinc oxide, or a conductive material having translucency such as indium tin oxide added with silicon oxide. Also, a laminated structure of the above translucent conductive material and the above metal may be used. Yes. Yes.

[0257] Subsequently, an insulator 280 and an insulator 282 are provided above the transistor 200.

[0258] For the insulator 280, it is preferable to use an oxide containing more oxygen than oxygen satisfying the stoichiometric composition. That is, in the insulator 280, oxygen is present in excess of the stoichiometric composition. Yes. It is preferable that a region where oxygen is excessive (hereinafter also referred to as an excessive oxygen region) is formed. In particular, when an oxide semiconductor is used for the transistor 200, by providing an insulator having an excessive oxygen region in an interlayer film or the like near the transistor 200, oxygen deficiency of the transistor 200 can be reduced, and reliability can be improved. When an oxide semiconductor is used for the transistor 200, by providing an insulator having an excessive oxygen region in an interlayer film or the like near the transistor 200, oxygen deficiency of the transistor 200 can be reduced, and reliability can be improved. When an oxide semiconductor is used for the transistor 200, by providing an insulator having an excessive oxygen region in an interlayer film or the like near the transistor 200, oxygen deficiency of the transistor 200 can be reduced, and reliability can be improved. When an oxide semiconductor is used for the transistor 200, by providing an insulator having an excessive oxygen region in an interlayer film or the like near the transistor 200, oxygen deficiency of the transistor 200 can be reduced, and reliability can be improved.

[0259] Specifically, as the insulator having an excessive oxygen region, it is preferable to use an oxide material in which a part of oxygen is desorbed by heating. The oxide that desorbs oxygen by heating is an oxide film in which the desorption amount of oxygen in terms of oxygen atoms is 1.0×10 atoms / cm or more, preferably 18 atoms / cm 3 or more, preferably 3.0×10 20 atoms / cm 3 or more. The surface temperature of the film during the above TDS analysis is preferably in the range of 100°C or higher and 700°C or lower, or 100°C or higher and 500°C or lower. and 500°C or lower.

[0260] For example, as such a material, it is preferable to use a material containing silicon oxide or silicon oxynitride. Alternatively, a metal oxide can also be used. In this specification, silicon oxynitride refers to a material having a higher oxygen content than nitrogen in its composition, and silicon oxynitride refers to a material having a higher nitrogen content than oxygen in its composition. For example, as such a material, it is preferable to use a material containing silicon oxide or silicon oxynitride. Alternatively, a metal oxide can also be used. In this specification, silicon oxynitride refers to a material having a higher oxygen content than nitrogen in its composition, and silicon oxynitride refers to a material having a higher nitrogen content than oxygen in its composition. For example, as such a material, it is preferable to use a material containing silicon oxide or silicon oxynitride. Alternatively, a metal oxide can also be used. In this specification, silicon oxynitride refers to a material having a higher oxygen content than nitrogen in its composition, and silicon oxynitride refers to a material having a higher nitrogen content than oxygen in its composition. For example, as such a material, it is preferable to use a material containing silicon oxide or silicon oxynitride. Alternatively, a metal oxide can also be used. In this specification, silicon oxynitride refers to a material having a higher oxygen content than nitrogen in its composition, and silicon oxynitride refers to a material having a higher nitrogen content than oxygen in its composition.

[0261] Further, the insulator 280 covering the transistor 200 may function as a planarization film covering the uneven shape below it. Further, the insulator 280 covering the transistor 200 may function as a planarization film covering the uneven shape below it.

[0262] The insulator 282 is, for example, aluminum oxide, hafnium oxide, etc., which are oxygen or water It is preferable to use an insulating film that is barrier - resistant to the element. When formed using such a material, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside. When formed using such a material, it functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside. functions as a layer that prevents the release of oxygen from the oxide 230 and the incorporation of impurities such as hydrogen from the outside.

[0263] By having the above - described configuration, a transistor having an oxide semiconductor with a large on - current can be provided. Or, a transistor having an oxide semiconductor with a small off - current can be provided. Or, by using a transistor having the above - described configuration in a semiconductor device, the variation in the electrical characteristics of the semiconductor device can be suppressed and the reliability can be improved. Also, a semiconductor device with reduced power consumption can be provided. By having the above - described configuration, a transistor having an oxide semiconductor with a large on - current can be provided. Or, a transistor having an oxide semiconductor with a small off - current can be provided. Or, by using a transistor having the above - described configuration in a semiconductor device, the variation in the electrical characteristics of the semiconductor device can be suppressed and the reliability can be improved. Also, a semiconductor device with reduced power consumption can be provided. By having the above - described configuration, a transistor having an oxide semiconductor with a large on - current can be provided. Or, a transistor having an oxide semiconductor with a small off - current can be provided. Or, by using a transistor having the above - described configuration in a semiconductor device, the variation in the electrical characteristics of the semiconductor device can be suppressed and the reliability can be improved. Also, a semiconductor device with reduced power consumption can be provided. By having the above - described configuration, a transistor having an oxide semiconductor with a large on - current can be provided. Or, a transistor having an oxide semiconductor with a small off - current can be provided. Or, by using a transistor having the above - described configuration in a semiconductor device, the variation in the electrical characteristics of the semiconductor device can be suppressed and the reliability can be improved. Also, a semiconductor device with reduced power consumption can be provided. By having the above - described configuration, a transistor having an oxide semiconductor with a large on - current can be provided. Or, a transistor having an oxide semiconductor with a small off - current can be provided. Or, by using a transistor having the above - described configuration in a semiconductor device, the variation in the electrical characteristics of the semiconductor device can be suppressed and the reliability can be improved. Also, a semiconductor device with reduced power consumption can be provided.

[0264] <Transistor Structure 2> FIG. 13 shows an example of a structure applicable to the transistor 200. FIG. 13(A) shows the top surface of the transistor 200. For clarity of the figure, some films are omitted in FIG. 13(A). Also, FIG. 13(B) is a cross - sectional view corresponding to the dashed - dotted line X1 - X2 shown in FIG. 13(A), and FIG. 13(C) is a cross - sectional view corresponding to Y1 - Y2. FIG. 13 shows an example of a structure applicable to the transistor 200. FIG. 13(A) shows the top surface of the transistor 200. For clarity of the figure, some films are omitted in FIG. 13(A). Also, FIG. 13(B) is a cross - sectional view corresponding to the dashed - dotted line X1 - X2 shown in FIG. 13(A), and FIG. 13(C) is a cross - sectional view corresponding to Y1 - Y2. In the transistor 200 shown in FIG. 13, the same reference numerals are assigned to the structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12. In the transistor 200 shown in FIG. 13, the same reference numerals are assigned to the structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12.

[0265] In the transistor 200 shown in FIG. 13, the same reference numerals are assigned to the structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12. In the transistor 200 shown in FIG. 13, the same reference numerals are assigned to the structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12.

[0266] The structure shown in FIG. 13 provides the conductor 260 in a two - layer structure. For example, an oxide typified by In - Ga - Zn oxide can be used as the conductor 260a. The oxide semiconductor typified by In - Ga - Zn oxide becomes conductive when nitrogen or hydrogen is supplied. For example, an oxide typified by In - Ga - Zn oxide can be used as the conductor 260a. The oxide semiconductor typified by In - Ga - Zn oxide becomes conductive when nitrogen or hydrogen is supplied. The oxide semiconductor typified by In - Ga - Zn oxide becomes conductive when nitrogen or hydrogen is supplied. The carrier density increases. In other words, it functions as an oxide conductor (OC). Therefore, by providing a metal nitride as the conductor 260b, since the oxide semiconductor has a high carrier density, the conductor 260a functions as a gate electrode.

[0267] As the conductor 260a, an oxide semiconductor typified by In-Ga-Zn oxide can be used. In addition, as the conductor 260a, a conductive material having translucency such as indium tin oxide (ITO), 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 tin oxide containing silicon (also referred to as In-Sn-Si oxide: ITSO), etc. can also be applied.

[0268] By using a metal nitride as the conductor 260b, the constituent elements in the metal nitride (particularly nitrogen) diffuse into the conductor 260a to reduce the resistance, and the resistance can also be reduced by the damage during the film formation of the conductor 260b (for example, sputtering damage, etc.). Note that the conductor 260b may have a laminated structure of two or more layers. For example, by laminating a low-resistance metal film on the metal nitride, a transistor with a small drive voltage can be provided.

[0269] In addition, as a method for forming the conductor 260a, a sputtering method is preferably used, and it is preferably formed in an atmosphere containing oxygen gas during the formation. By forming the conductor 260a in an atmosphere containing oxygen gas during the formation, an excess oxygen region can be formed in the insulator 250. Note that ​​​​​​​​​​​​The method for forming the conductor 260a is not limited to the sputtering method, and other methods, for example the ALD method may be used.

[0270] Furthermore, an insulator 270 is provided so as to cover the conductor 260 in the structure shown in FIG. 13. When an oxide material from which oxygen desorbs is used for the insulator 280, the insulator 270 uses a material having a barrier property against oxygen. With this configuration, the oxygen deficiency of the conductor 260a is compensated, whereby a decrease in the carrier density can be suppressed, and the conductor 260b can be prevented from being oxidized by the diffused oxygen. For example, a metal oxide such as aluminum oxide can be used for the insulator 270. Also, the insulator 270 may be provided with a film thickness sufficient to prevent oxidation of the conductor 260.

[0271] For example, a metal oxide such as aluminum oxide can be used for the insulator 270. Also, the insulator 270 may be provided with a film thickness sufficient to prevent oxidation of the conductor 260.

[0272] Also, as shown in the figure, the conductor 205c may be provided using a conductor having a barrier property without providing the insulator 220 and the insulator 222. With this configuration, even when the insulator 224 has an excess oxygen region, the conductor 205b can be prevented from reacting with the oxygen in the excess oxygen region and generating an oxide.

[0273] Also, insulators 243a and 243b may be provided on the conductors 240a and 240b. The insulators 243a and 243b use a material having a barrier property against oxygen. With this configuration, when forming the oxide 230c on the conductors 240a and 240b, oxidation can be suppressed. Also, the oxygen in the excess oxygen region of the insulator 280 reacts with the conductors 240a and 240b to form an acid ​ It can be prevented from changing.

[0274] For the insulators 243a and 243b, for example, metal oxides can be used. In particular, it is preferable to use an insulating film that is barrier against oxygen and hydrogen, such as aluminum oxide, hafnium oxide, and gallium oxide. Also, silicon nitride formed by CVD method may be used.

[0275] Therefore, with this configuration, the range of material selection for the conductors 240a, 240b, 205, and also the conductor 260 can be widened. For example, for the conductor 205b and the conductor 260b, a material with low oxidation resistance but high conductivity, such as aluminum, can be used. Also, for example, a conductor that is easy to form a film or process can be used.

[0276] Also, oxidation of the conductors 205 and 260 can be suppressed, and oxygen desorbed from the insulators 224 and 280 can be efficiently supplied to the oxide 230. Also, by using a conductor with high conductivity for the conductors 205 and 260, a transistor 200 with low power consumption can be provided.

[0277] <Transistor Structure 3> FIG. 14 shows an example of a structure applicable to the transistor 200. FIG. 14(A) shows the top surface of the transistor 200. For clarity of the figure, some films are omitted in FIG. 14(A). Also, FIG. 14(B) is a cross-sectional view corresponding to the dashed line X1-X2 shown in FIG. 14(A), and FIG. 14(C) is a cross-sectional view corresponding to Y1-Y2.

[0278] In the transistor 200 shown in FIG. 14, the same reference numerals are given to the structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12. The structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12 are given the same reference numerals.

[0279] The structure shown in FIG. 14 provides the conductor 260 in a two-layer structure. As the two-layer structure, the same materials may be laminated. For example, the conductor 260a is formed using thermal CVD, MOCVD, or ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. Therefore, a highly reliable transistor 200 can be provided. Subsequently, the conductor 260b is formed using a sputtering method. At this time, by having the conductor 260a on the insulator 250, it is possible to suppress the damage during film formation of the conductor 260b from affecting the insulator 25

[0280] 0. Also, compared to the ALD method, the sputtering method has a high film formation rate, so the yield is high and the productivity can be improved. Furthermore, the structure shown in FIG. 14 provides an insulator 270 so as to cover the conductor 260. When using an oxide material in which oxygen desorbs from the insulator 280, the insulator 270 uses a material having basicity with respect to oxygen. With this configuration, the oxygen deficiency of the conductor 260a is compensated, suppressing a decrease in carrier density, and also preventing the conductor 260b from being oxidized by the diffused oxygen.

[0281]

[0282] ​​​​​For example, as the insulator 270, metal oxides such as aluminum oxide can be used. Also, the insulator 270 may be provided with a film thickness sufficient to prevent oxidation of the conductor 260. .

[0283] <Transistor Structure 4> FIG. 15 shows an example of a structure applicable to the transistor 200. FIG. 15(A) shows the top surface of the transistor 200. For clarity of the drawing, some films are omitted in FIG. 15(A). Further, FIG. 15(B) is a cross-sectional view corresponding to the dashed line X1-X2 shown in FIG. 15(A), and FIG. 15(C) is a cross-sectional view corresponding to Y1-Y2. In the transistor 200 shown in FIG. 15, structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12 are denoted by the same reference numerals. In the structure shown in FIG. 15, the conductor 260 that functions as a gate electrode includes the conductor 260a, the conductor 260b, and the conductor 260c. Also, the oxide 230c may cover the side surface of the oxide 230b and may be cut on the insulator 224. The structure shown in FIG. 15 provides the conductor 260 in a three-layer structure. It may also be a single-layer, two-layer structure, or a laminated structure of four or more layers. When it is a two-layer structure, the same material may be laminated and provided. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed.

[0284] In the transistor 200 shown in FIG. 15, structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12 are denoted by the same reference numerals. In the structure shown in FIG. 15, the conductor 260 that functions as a gate electrode includes the conductor 260a, the conductor 260b, and the conductor 260c. Also, the oxide 230c may cover the side surface of the oxide 230b and may be cut on the insulator 224.

[0285] The structure shown in FIG. 15 provides the conductor 260 in a three-layer structure. It may also be a single-layer, two-layer structure, or a laminated structure of four or more layers. When it is a two-layer structure, the same material may be laminated and provided. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. In the structure shown in FIG. 15, the conductor 260 that functions as a gate electrode includes the conductor 260a, the conductor 260b, and the conductor 260c. Also, the oxide 230c may cover the side surface of the oxide 230b and may be cut on the insulator 224. The structure shown in FIG. 15 provides the conductor 260 in a three-layer structure. It may also be a single-layer, two-layer structure, or a laminated structure of four or more layers. When it is a two-layer structure, the same material may be laminated and provided. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed.

[0286] The structure shown in FIG. 15 provides the conductor 260 in a three-layer structure. It may also be a single-layer, two-layer structure, or a laminated structure of four or more layers. When it is a two-layer structure, the same material may be laminated and provided. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. It may also be a single-layer, two-layer structure, or a laminated structure of four or more layers. When it is a two-layer structure, the same material may be laminated and provided. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. It may also be a single-layer, two-layer structure, or a laminated structure of four or more layers. When it is a two-layer structure, the same material may be laminated and provided. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. For example, the conductor 260a is formed using a thermal CVD method, an MOCVD method, or an ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. By forming using the ALD method or the like, damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductor 260a with high coating properties can be formed. Thus, a highly reliable transistor 200 can be provided.

[0287] Subsequently, the conductor 260b is formed using a sputtering method. At this time, by having the conductor 260a on the insulator 250, it is possible to suppress the damage during the film formation of the conductor 260b from affecting the insulator 250. Also, compared with the ALD method, since the sputtering method has a high film formation rate, the yield is high and the productivity can be improved. on the insulator 250, it is possible to suppress the damage during the film formation of the conductor 260b from affecting the insulator 250. Also, compared with the ALD method, since the sputtering method has a high film formation rate, the yield is high and the productivity can be improved. on the insulator 250, it is possible to suppress the damage during the film formation of the conductor 260b from affecting the insulator 250. Also, compared with the ALD method, since the sputtering method has a high film formation rate, the yield is high and the productivity can be improved. on the insulator 250, it is possible to suppress the damage during the film formation of the conductor 260b from affecting the insulator 250. Also, compared with the ALD method, since the sputtering method has a high film formation rate, the yield is high and the productivity can be improved.

[0288] Also, the conductor 260b is formed using a highly conductive material such as tantalum, tungsten, copper, or aluminum. Further, the conductor 260c formed on the conductor 260b is preferably formed using a conductor with high oxidation resistance such as tungsten nitride. Also, the conductor 260b is formed using a highly conductive material such as tantalum, tungsten, copper, or aluminum. Further, the conductor 260c formed on the conductor 260b is preferably formed using a conductor with high oxidation resistance such as tungsten nitride. Also, the conductor 260b is formed using a highly conductive material such as tantalum, tungsten, copper, or aluminum. Further, the conductor 260c formed on the conductor 260b is preferably formed using a conductor with high oxidation resistance such as tungsten nitride.

[0289] For example, when an oxide material from which oxygen desorbs is used for the insulator 280, a conductor with high oxidation resistance is used for the conductor 260c having a large contact area with the insulator 280 having an excess oxygen region, so that oxygen desorbed from the excess oxygen region can be prevented from being absorbed by the conductor 260. Also, oxidation of the conductor 260 can be suppressed, and oxygen desorbed from the insulator 280 can be efficiently supplied to the oxide 230. Also, by using a highly conductive conductor for the conductor 260b, a transistor 200 with low power consumption can be provided. For example, when an oxide material from which oxygen desorbs is used for the insulator 280, a conductor with high oxidation resistance is used for the conductor 260c having a large contact area with the insulator 280 having an excess oxygen region, so that oxygen desorbed from the excess oxygen region can be prevented from being absorbed by the conductor 260. Also, oxidation of the conductor 260 can be suppressed, and oxygen desorbed from the insulator 280 can be efficiently supplied to the oxide 230. Also, by using a highly conductive conductor for the conductor 260b, a transistor 200 with low power consumption can be provided. For example, when an oxide material from which oxygen desorbs is used for the insulator 280, a conductor with high oxidation resistance is used for the conductor 260c having a large contact area with the insulator 280 having an excess oxygen region, so that oxygen desorbed from the excess oxygen region can be prevented from being absorbed by the conductor 260. Also, oxidation of the conductor 260 can be suppressed, and oxygen desorbed from the insulator 280 can be efficiently supplied to the oxide 230. Also, by using a highly conductive conductor for the conductor 260b, a transistor 200 with low power consumption can be provided. For example, when an oxide material from which oxygen desorbs is used for the insulator 280, a conductor with high oxidation resistance is used for the conductor 260c having a large contact area with the insulator 280 having an excess oxygen region, so that oxygen desorbed from the excess oxygen region can be prevented from being absorbed by the conductor 260. Also, oxidation of the conductor 260 can be suppressed, and oxygen desorbed from the insulator 280 can be efficiently supplied to the oxide 230. Also, by using a highly conductive conductor for the conductor 260b, a transistor 200 with low power consumption can be provided. For example, when an oxide material from which oxygen desorbs is used for the insulator 280, a conductor with high oxidation resistance is used for the conductor 260c having a large contact area with the insulator 280 having an excess oxygen region, so that oxygen desorbed from the excess oxygen region can be prevented from being absorbed by the conductor 260. Also, oxidation of the conductor 260 can be suppressed, and oxygen desorbed from the insulator 280 can be efficiently supplied to the oxide 230. Also, by using a highly conductive conductor for the conductor 260b, a transistor 200 with low power consumption can be provided. For example, when an oxide material from which oxygen desorbs is used for the insulator 280, a conductor with high oxidation resistance is used for the conductor 260c having a large contact area with the insulator 280 having an excess oxygen region, so that oxygen desorbed from the excess oxygen region can be prevented from being absorbed by the conductor 260. Also, oxidation of the conductor 260 can be suppressed, and oxygen desorbed from the insulator 280 can be efficiently supplied to the oxide 230. Also, by using a highly conductive conductor for the conductor 260b, a transistor 200 with low power consumption can be provided.

[0290] Also, as shown in FIG. 15(C), in the channel width direction of the transistor 200, the oxide 230b is covered by the conductor 260. Also, since the insulator 224 has a convex portion, the side surface of the oxide 230b can also be covered by the conductor 260. For example, the insulator 224 Also, as shown in FIG. 15(C), in the channel width direction of the transistor 200, the oxide 230b is covered by the conductor 260. Also, since the insulator 224 has a convex portion, the side surface of the oxide 230b can also be covered by the conductor 260. For example, the insulator 224 Also, as shown in FIG. 15(C), in the channel width direction of the transistor 200, the oxide 230b is covered by the conductor 260. Also, since the insulator 224 has a convex portion, the side surface of the oxide 230b can also be covered by the conductor 260. For example, the insulator 224 By adjusting the shape of the convex portion, in the region where the insulator 224 and the oxide 230c are in contact, it is preferable that the bottom surface of the conductor 260 is on the substrate side rather than the bottom surface of the oxide 230b. That is, the transistor 200 has a structure capable of electrically surrounding the oxide 230b by the electric field of the conductor 260. In this way, the structure of the transistor that electrically surrounds the oxide 230b by the electric field of the conductor is called a surrounded channel (s-channel) structure. The transistor 2 00 of the s-channel structure can also form a channel in the entire oxide 230b (bulk). In the s-channel structure, the drain current of the transistor can be increased, and a larger on-current (the current flowing between the source and the drain when the transistor is in the on state) can be obtained. Also, the entire region of the channel formation region formed in the oxide 230b can be depleted by the electric field of the conductor 260. Therefore, in the s-channel structure, the off-current of the transistor can be further reduced. By reducing the channel width, the effect of increasing the on-current and the effect of reducing the off-current due to the s-channel structure can be enhanced.

[0291] <Transistor Structure 5> FIG. 16 shows an example of a structure applicable to the transistor 200. FIG. 16(A) shows the top surface of the transistor 200. For clarity of the figure, some films are omitted in FIG. 16(A). Also, FIG. 16(B) is a cross-sectional view corresponding to the dashed line X1-X2 shown in FIG. 16(A), and FIG. 16(C) is a cross-sectional view corresponding to Y1-Y2.

[0292] In the transistor 200 shown in FIG. 16, the same reference numerals are assigned to the structures having the same functions as the structure constituting the transistor 200 shown in FIG. 12. The structures having the same functions as the structure constituting are assigned the same reference numerals.

[0293] In the structure shown in FIG. 16, the conductor functioning as a source or a drain has a laminated structure. As the conductors 240a and 240b, conductors having high adhesion with the oxide 230b are used. For the conductors 241a and 241b, it is preferable to use materials having high conductivity. Also, the conductors 240a and 240b are preferably formed using the ALD method. By forming using the ALD method or the like, the coating property can be improved.

[0294] For example, when a metal oxide having indium is used for the oxide 230b, titanium nitride or the like may be used for the conductors 240 a and 240b. Also, for the conductors 241a and 241b, by using materials having high conductivity such as tantalum, tungsten, copper, and aluminum, a transistor 200 with high reliability and low power consumption can be provided.

[0295] Also, as shown in FIG. 16(C), in the channel width direction of the transistor 200, the oxide 230b is covered with the conductor 260. Also, since the insulator 222 has a convex portion, the side surface of the oxide 230b can also be covered with the conductor 260.

[0296] Here, when a high-k material such as hafnium oxide is used for the insulator 222, since the relative permittivity of the insulator 222 is large, the equivalent oxide thickness (EOT: Equivalent Oxide Thickness) can be made small. Therefore, for the oxide 230, Without weakening the influence of the electric field from the conductor 205, the physical thickness of the insulator 222 allows the distance between the conductor 205 and the oxide 230 to be increased. Therefore, the distance between the conductor 205 and the oxide 230 can be adjusted according to the film thickness of the insulator 222. possible.

[0297] For example, by adjusting the shape of the convex portion of the insulator 222, in the region where the insulator 222 and the oxide 230c are in contact, it is preferable that the bottom surface of the conductor 260 is closer to the substrate side than the bottom surface of the oxide 230b. That is, the transistor 200 has a structure in which the oxide 230b can be electrically surrounded by the electric field of the conductor 260. In this way, the structure of the transistor in which the oxide 230b is electrically surrounded by the electric field of the conductor is called a surrounded channel (s-channel) structure. The transistor 200 having an s-channel structure can also form a channel in the entire oxide 230b (bulk). In the s-channel structure, the drain current of the transistor can be increased, and a larger on-current (the current flowing between the source and the drain when the transistor is in the on state) can be obtained. Also, the entire channel formation region formed in the oxide 230b can be depleted by the electric field of the conductor 260. Therefore, in the s-channel structure, the off-current of the transistor can be further reduced. In addition, by reducing the channel width, the effects of increasing the on-current and reducing the off-current due to the s-channel structure can be enhanced. ounded channel(s-channel) structure and called. s-channel

[0298] <Transistor Structure 6> ​​​​​​​​​​​​FIG. 17 shows an example of a structure adaptable to the transistor 200. FIG. 17(A) shows the top surface of the transistor 200. For clarity of the drawing, some films are omitted in FIG. 17(A). FIG. 17(B) is a cross-sectional view corresponding to the dashed line X1-X2 shown in FIG. 17(A), and FIG. 17(C) is a cross-sectional view corresponding to Y1-Y2. In the transistor 200 shown in FIG. 17, in the structure having the same function as the structure constituting the transistor 200 shown in FIG. 12, the same reference numerals are added. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. Also, the conductor 240a, the conductor 240b, and the oxide 230b are in contact with the insulator 280 having an excess oxygen region via the oxide 230d. Therefore, the oxide 230d is interposed between the insulator 280 and the oxide 230b having a region where a channel is formed, so that impurities such as hydrogen, water, and halogen can be prevented from diffusing from the insulator 280 to the oxide 230b.

[0299] Note that in the transistor 200 shown in FIG. 17, in the structure having the same function as the structure constituting the transistor 200 shown in FIG. 12, the same reference numerals are added. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved.

[0300] In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved.

[0301] Also, the conductor 240a, the conductor 240b, and the oxide 230b are in contact with the insulator 280 having an excess oxygen region via the oxide 230d. Therefore, the oxide 230d is interposed between the insulator 280 and the oxide 230b having a region where a channel is formed, so that impurities such as hydrogen, water, and halogen can be prevented from diffusing from the insulator 280 to the oxide 230b. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved. In the transistor 200 shown in FIG. 17, an opening is formed in the insulator 280, and an oxide 230c, an insulator 250, and a conductor 260 are formed. One end of either the conductor 240a or the conductor 240b coincides with the end of the opening formed in the insulator 280. Further, three ends of the conductor 240a and the conductor 240b coincide with a part of the ends of the oxide 230a and the oxide 230b. Therefore, the conductor 240a and the conductor 240b can be shaped simultaneously with the opening of the oxide 230 or the insulator 280. Thus, the mask and the process can be reduced. Also, the yield and productivity can be improved.

[0302] Furthermore, the transistor 200 shown in FIG. 17 includes a conductor 240a and a conductor 240b. Since the conductor 260 and the conductor 240 have a structure in which they hardly overlap each other, the conductor 260 and the conductor 240 The parasitic capacitance between 240a and 240b can be reduced. It is possible to provide a transistor 200 with high

[0303] <Transistor structure 8> FIG. 18 shows an example of a structure applicable to a transistor 200. 18(A) shows the top surface of the transistor 200. For clarity of the drawing, some of the films are not shown in FIG. In addition, FIG. 18B corresponds to the dashed line X1-X2 shown in FIG. 18(C) is a cross-sectional view taken along line Y1-Y2.

[0304] In the transistor 200 shown in FIG. 18, the transistor 200 shown in FIG. The same reference numerals are used to designate structures having the same functions as the structures they constitute.

[0305] The transistor 200 shown in FIG. 18 does not have an oxide 230d. When a highly oxidation-resistant conductor is used for the conductor 240a and the conductor 240b, the oxide 23 0d is not necessarily required. Therefore, the number of masks and processes can be reduced. In addition, the yield and productivity can be improved.

[0306] The insulator 224 is provided only in the area overlapping the oxide 230a and the oxide 230b. In this case, the insulator 222 may be used as an etching stopper, and the oxide 230a, The oxide 230b and the insulator 224 can be processed. Therefore, the yield and production efficiency can be improved.

[0307] Furthermore, since the transistor 200 shown in FIG. 18 has a structure in which the conductor 240a and the conductor 240b and the conductor 260 hardly overlap, the parasitic capacitance generated between the conductor 260 and the conductors 240 a and 240b can be reduced. That is, a transistor 200 with a high operating frequency can be provided.

[0308] <Method for manufacturing a transistor> An example of the method for manufacturing the transistor shown in FIG. 12 will be described below with reference to FIGS. 19 to 22. Explain.

[0309] First, a substrate is prepared (not shown). There is no major limitation on the substrate, but it is preferably at least heat-resistant enough to withstand the subsequent heat treatment. For example, glass substrates such as barium borosilicate glass and aluminosilicate glass, ceramic substrates, quartz substrates, sapphire substrates, etc. can be used. Also, single crystal semiconductor substrates made of silicon or silicon carbide, polycrystalline semiconductor substrates, silicon germanium, gallium arsenide, indium arsenide, compound semiconductor substrates made of indium gallium arsenide, SOI (Silicon On Insulator) substrates, GOI (Germanium on Insulator ) substrates, etc. can also be applied, and those with semiconductor elements provided on these substrates can be used as the substrate. It may be used as a substrate.

[0310] Also, as the substrate, a flexible substrate may be used to fabricate a semiconductor device. A semi-flexible To fabricate a conductor device, transistors may be directly fabricated on a flexible substrate, or transistors may be fabricated on another fabrication substrate and then peeled and transferred onto the flexible substrate. In addition, in order to peel and transfer from the fabrication substrate to the flexible substrate, a release layer may be provided between the fabrication substrate and the transistor including an oxide semiconductor.

[0311] Next, insulators 214 and 216 are formed. Subsequently, a resist mask 290 is formed on the insulator 216 using a lithography method or the like, and unnecessary portions of the insulator 214 and the insulator 216 are removed (FIG. 19(A)). Then, by removing the resist mask 290, an opening can be formed.

[0312] Here, a method for processing a film to be processed will be described. When the film to be processed is finely processed, various fine processing techniques can be used. For example, a method of performing a slimming process on a resist mask formed by a lithography method or the like may be used. Also, a dummy pattern is formed by a lithography method or the like, sidewalls are formed on the dummy pattern, and then the dummy pattern is removed. The remaining sidewalls are used as a resist mask to etch the film to be processed. In addition, as the etching of the film to be processed, anisotropic dry etching is preferably used in order to achieve a high aspect ratio. Also, a hard mask made of an inorganic film or a metal film may be used.

[0313] As the light used for forming the resist mask, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light obtained by mixing these can be used. In addition, ultraviolet rays, KrF laser light, ArF laser light, or the like can also be used. Also, exposure may be performed by immersion lithography technology. Further, as the light used for exposure, extreme ultraviolet light (EUV: Extreme Ultra-violet) or X-rays may be used. Also, instead of the light used for exposure, an electron beam can also be used. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because extremely fine processing becomes possible. When performing exposure by scanning any of these electron beams, a photomask is unnecessary.

[0314] Before forming the resist film that serves as a resist mask, an organic resin film having a function of improving the adhesion between the film to be processed and the resist film may be formed. The organic resin film can be formed, for example, by spin coating or the like so as to cover the step below it and flatten the surface, and the variation in the thickness of the resist mask provided above the organic resin film can be reduced. Also, when performing particularly fine processing, as the organic resin film, it is preferable to use a material that functions as an antireflection film for the light used for exposure. Examples of such an organic resin film having such a function include a BARC (Bottom Anti-Reflection Coating) film. The organic resin film may be removed simultaneously with the removal of the resist mask or after removing the resist mask. Subsequently, conductor 205A and conductor 205B are formed on insulator 214 and insulator 216. Conductor 205A and

[0315] conductor 205B are formed by a sputtering method, an evaporation method, a CVD method (including a thermal CVD method, a MOCVD method, a PECVD method, etc.). ​This can be achieved. Also, to reduce damage caused by plasma, thermal CVD method, MOCVD method or ALD method is preferred (Fig. 19(B)).

[0316] Subsequently, unnecessary portions of conductor 205A and conductor 205B are removed. For example, by etch back treatment, or by chemical mechanical polishing (CMP) treatment, etc., until insulator 216 is exposed, a part of conductor 205A and conductor 205B is removed to form conductor 205 (Fig. 19(C)). At this time, insulator 216 can also be used as a stopper layer, and insulator 2 16 may become thinner.

[0317] Here, CMP treatment is a method of planarizing the surface of the workpiece by a combined chemical and mechanical action. More specifically, an abrasive cloth is attached to the polishing stage, and while supplying slurry (abrasive) between the workpiece and the abrasive cloth, the polishing stage and the workpiece are rotated or oscillated respectively, and by the chemical reaction between the slurry and the workpiece surface and the mechanical polishing action between the abrasive cloth and the workpiece, the surface of the workpiece is polished.

[0318] Note that CMP treatment may be performed only once or multiple times. When performing CMP treatment in multiple steps, it is preferable to perform primary polishing with a high polishing rate first, and then finish polishing with a low polishing rate. Thus, polishing with different polishing rates may be combined.

[0319] Next, insulator 220, insulator 222, and insulator 224 are formed (Fig. 19(D)). Note that insulator 220 and insulator 222 are not necessarily provided. For example, insulator ​When 224 has an excess oxygen region, a conductor having a barrier property may be formed on the conductor 205. By forming a conductor having a barrier property, it is possible to suppress the reaction of the conductor 205 with the oxygen in the excess oxygen region and the generation of an oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. The insulators 220, 222, and 224 can be formed, for example, by sputtering, chemical vapor deposition (CVD: Chemical Vapor Deposition) methods (thermal CVD method, metal organic CVD (MOCVD: Metal Organic Chemical Vapor Deposition) method, plasma enhanced CVD (PECVD: Plasma Enhanced Chemical Vapor Deposition) method, etc.), molecular beam epitaxy (MBE: Molecular Beam Epitaxy) method, atomic layer deposition (ALD: Atomic Layer Deposition) method, or pulsed laser deposition (PLD: Pulsed Laser Deposition) method. In particular, when the insulator is formed by a CVD method, preferably an ALD method or the like, it is preferable because the coating property can be improved. Also, to reduce damage by plasma, a thermal CVD method, MOCVD method, or ALD method is preferable.

[0320] For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide.

[0321] For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. For the insulators 220, 222, and 224, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, aluminum nitride, etc. may be used. In particular, for the insulator 222, it is preferable to use a high-k material such as hafnium oxide. , TEOS (Tetra-Ethyl-Ortho-Silicate) or silane and the like are reacted with oxygen or nitrous oxide or the like to form silicon oxide with good step coverage The film can also be used.

[0322] Note that the insulator 220, the insulator 222, and the insulator 224 are preferably formed by continuous film formation. By continuously forming the film, an insulator with high reliability can be formed without impurities adhering to the interface between the insulator 220 and the insulator 222 and the interface between the insulator 222 and the insulator 224. This can be achieved.

[0323] Subsequently, the oxide 230A that becomes the oxide 230a and the oxide 230B that becomes the oxide 230b are formed in order. It is preferable to continuously form the film without exposing it to the atmosphere.

[0324] Thereafter, a conductive film 240A that becomes the conductor 240a and the conductor 240b is formed on the oxide 230A. The conductive film 240A has a barrier property against hydrogen or oxygen, and it is preferable to use a material with high oxidation resistance. Also, although it is shown as a single layer in the figure, a laminated structure of two or more layers may be used. Subsequently, a resist mask 292 is formed in the same manner as described above (Fig. 19(E)). Using the resist mask 292, unnecessary portions of the conductive film 240A are removed by etching to form an island-shaped conductive layer 240B (Fig. 20(A)). Thereafter, using the conductive layer 240B as a mask, unnecessary portions of the oxide 230A and the oxide 230B are removed by etching.

[0325]

[0326] ​​​​​​​​​​At this time, the insulator 224 may also be processed into an island shape. For example, by using the barrier insulator 222 as an etching stopper film, even in a structure where the total film thickness of the insulator 220, the insulator 222, and the insulator 224 is thin, over-etching to the underlying wiring layer can be prevented. Also, by reducing the total film thickness of the insulator 220, the insulator 222, and the insulator 224, voltage from the conductor 205 can be efficiently applied, thus providing a transistor with low power consumption. By using the barrier insulator 222 as an etching stopper film, even in a structure where the total film thickness of the insulator 220, the insulator 222, and the insulator 224 is thin, over-etching to the underlying wiring layer can be prevented. Also, by reducing the total film thickness of the insulator 220, the insulator 222, and the insulator 224, voltage from the conductor 205 can be efficiently applied, thus providing a transistor with low power consumption. After that, by removing the resist mask, a stacked structure of the island-shaped oxide 230a, the island-shaped oxide 230b, and the island-shaped conductive layer 240B can be formed (Fig. 20(B)). By using the barrier insulator 222 as an etching stopper film, even in a structure where the total film thickness of the insulator 220, the insulator 222, and the insulator 224 is thin, over-etching to the underlying wiring layer can be prevented. Also, by reducing the total film thickness of the insulator 220, the insulator 222, and the insulator 224, voltage from the conductor 205 can be efficiently applied, thus providing a transistor with low power consumption.

[0327] Subsequently, by removing the resist mask, a stacked structure of the island-shaped oxide 230a, the island-shaped oxide 230b, and the island-shaped conductive layer 240B can be formed (Fig. 20(B)). After that, by removing the resist mask, a stacked structure of the island-shaped oxide 230a, the island-shaped oxide 230b, and the island-shaped conductive layer 240B can be formed (Fig. 20(B)). .

[0328] Subsequently, heat treatment is preferably performed (Fig. 20(C), the arrow in the figure represents heat treatment). . The heat treatment can be carried out at a temperature of 250°C or higher and 400°C or lower, preferably 320°C or higher and 380°C or lower, in an inert gas atmosphere, an atmosphere containing 10 ppm or more of an oxidizing gas, or in a reduced pressure state. Also, the heat treatment atmosphere may be an atmosphere containing 10 ppm or more of an oxidizing gas to supplement the desorbed oxygen after heat treatment in an inert gas atmosphere. By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 230b, can be removed. . The heat treatment can be carried out at a temperature of 250°C or higher and 400°C or lower, preferably 320°C or higher and 380°C or lower, in an inert gas atmosphere, an atmosphere containing 10 ppm or more of an oxidizing gas, or in a reduced pressure state. Also, the heat treatment atmosphere may be an atmosphere containing 10 ppm or more of an oxidizing gas to supplement the desorbed oxygen after heat treatment in an inert gas atmosphere. By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 230b, can be removed. . The heat treatment can be carried out at a temperature of 250°C or higher and 400°C or lower, preferably 320°C or higher and 380°C or lower, in an inert gas atmosphere, an atmosphere containing 10 ppm or more of an oxidizing gas, or in a reduced pressure state. Also, the heat treatment atmosphere may be an atmosphere containing 10 ppm or more of an oxidizing gas to supplement the desorbed oxygen after heat treatment in an inert gas atmosphere. By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 230b, can be removed. . The heat treatment can be carried out at a temperature of 250°C or higher and 400°C or lower, preferably 320°C or higher and 380°C or lower, in an inert gas atmosphere, an atmosphere containing 10 ppm or more of an oxidizing gas, or in a reduced pressure state. Also, the heat treatment atmosphere may be an atmosphere containing 10 ppm or more of an oxidizing gas to supplement the desorbed oxygen after heat treatment in an inert gas atmosphere. By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 230b, can be removed. . The heat treatment can be carried out at a temperature of 250°C or higher and 400°C or lower, preferably 320°C or higher and 380°C or lower, in an inert gas atmosphere, an atmosphere containing 10 ppm or more of an oxidizing gas, or in a reduced pressure state. Also, the heat treatment atmosphere may be an atmosphere containing 10 ppm or more of an oxidizing gas to supplement the desorbed oxygen after heat treatment in an inert gas atmosphere. By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 230b, can be removed. . Also, oxygen can be supplied from the insulator formed under the oxide 230a to the oxide 230a and the oxide 230b, reducing the oxygen deficiency in the oxide. . Also, oxygen can be supplied from the insulator formed under the oxide 230a to the oxide 230a and the oxide 230b, reducing the oxygen deficiency in the oxide.

[0329] Next, a resist mask 294 is formed on the island-shaped conductive layer 240B by the same method as above. It is removed (Fig. 20(D)). Subsequently, unnecessary portions of the conductive layer 240B are removed by etching. After that, by removing the resist mask 294, the conductor 240a and the conductor 240 b are formed (Fig. 21(A)). At this time, a part of the insulator 222 or the insulator 224 may be etched and thinned to form an s-channel structure.

[0330] Here, heat treatment may be performed. The conditions for the heat treatment may be the same as those described in Fig. 20(C). By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 2 30b, can be removed. Also, oxygen is supplied from the insulator formed below the oxide 230a to the oxide 230a and the oxide 230b, and the oxygen deficiency in the oxide can be reduced. Furthermore, when heat treatment is performed with an oxidizing gas, the oxidizing gas directly contacts the region where the channel is formed, so that the oxygen deficiency in the region where the channel is efficiently formed can be reduced.

[0331] Subsequently, the oxide 230c is formed. Here, heat treatment may also be performed (Fig. 21 (B), the arrow in the figure indicates heat treatment.). The conditions for the heat treatment may be the same as those described in Fig. 21(C). By the heat treatment, hydrogen, which is an impurity in the oxide 230a and the oxide 23 0b, can be removed. Also, oxygen is supplied from the insulator formed below the oxide 230a to the oxide 230a and the oxide 230b, and the oxygen deficiency in the oxide can be reduced. Furthermore, when heat treatment is performed with an oxidizing gas, the oxidizing gas directly contacts the region where the channel is formed, so that the oxygen deficiency in the region where the channel is efficiently formed can be reduced. ​​​​

[0332] The insulator 250 and the conductive film 260A serving as the conductor 260 are formed in sequence. Also, the conductive film 260A preferably has a barrier property against hydrogen or oxygen and a high oxidation resistance material is used for it. Also, although it is shown as a single layer in the figure, it may have a laminated structure of two or more layers as well.

[0333] For example, in the two-layer structure, the same material may be laminated and provided. The first conductive film is formed using the thermal CVD method, the MOCVD method or the ALD method. In particular, it is preferably formed using the ALD method. By forming using the ALD method or the like, the damage during film formation on the insulator 250 can be reduced. Also, by forming using the ALD method or the like, a conductive film 26 with high covering property 0A can be formed. Therefore, a highly reliable transistor 200 can be provided

[0334] Subsequently, the second conductive film is formed using the sputtering method. At this time, by having the first conductive film on the insulator 250, it is possible to suppress the damage during film formation of the second conductive film from affecting the insulator 250 Also, compared with the ALD method, since the sputtering method has a high film formation rate, the yield is high and the productivity can be improved. When forming the conductive film 260A, it is preferable to form it using a film formation gas that does not contain chlorine.

[0335] Next, a resist mask 296 is formed on the conductive film 260A by the same method as above ( FIG. 21(C)). Subsequently, unnecessary portions of the conductive film 260A are removed by etching to form the conductor 260, and then the resist mask 296 is removed (FIG. 22(A)). ​​​​​

[0336] Subsequently, an insulator 280 is formed on the conductor 260. The insulator 280 is an oxygen-containing insulator such as a silicon oxide film or a silicon oxynitride film. As a method of forming an insulator containing excess oxygen, the film formation conditions in the CVD method or the sputtering method are appropriately set to form a silicon oxide film or a silicon oxynitride film containing a large amount of oxygen in the film It is possible. Further, after forming a silicon oxide film or a silicon oxynitride film, oxygen may be added by ion implantation, ion doping method or plasma treatment. In particular, it is preferable to perform oxygen plasma treatment (Fig. 22(B), the arrow in the figure represents plasma treatment .). A typical oxygen plasma treatment is to treat the surface of an oxide semiconductor with radicals generated by glow discharge plasma of oxygen gas, but the gas for generating plasma

[0337] is not limited to oxygen only, but may be a mixed gas of oxygen gas and a rare gas. For example, in an atmosphere containing an oxidizing gas at a temperature of 250°C or higher 400°C or lower, preferably 300°C or higher and 400°C or lower, or it may be performed in a reduced pressure state. The oxygen plasma treatment dehydrates or dehydrogenates the insulator 280 and the oxide 230, and introduces excess oxygen into the insulator 280 to form an excess oxygen region It is possible. Further, oxygen deficiency occurs in the dehydrated or dehydrogenated oxide 230, resulting in a lower resistance. On the other hand, the oxygen deficiency of the oxide 230 is compensated by the excess oxygen in the insulator 280. Therefore, by the oxygen plasma treatment, the insulator 280 forms an excess oxygen region At the same time, impurities such as hydrogen and water can be removed. Also, in the oxide 2

[0338] The insulator 280 and the oxide 230 are dehydrated or dehydrogenated, and an excess oxygen region can be formed by introducing excess oxygen into the insulator 280. Also, oxygen deficiency occurs in the dehydrated or dehydrogenated oxide 230, resulting in a lower resistance. On the other hand, the oxygen deficiency of the oxide 230 is compensated by the excess oxygen in the insulator 280. Therefore, by the oxygen plasma treatment, the insulator 280 forms an excess oxygen region At the same time, impurities such as hydrogen and water can be removed. Also, in the oxide 2 resulting in a lower resistance. On the other hand, the oxygen deficiency of the oxide 230 is compensated by the excess oxygen in the insulator 280. Therefore, by the oxygen plasma treatment, the insulator 280 forms an excess oxygen region At the same time, impurities such as hydrogen and water can be removed. Also, in the oxide 2 30, the insulator 280 can remove hydrogen and water, which are impurities, while forming an excess oxygen region. Also, in the oxide 2 30 can remove hydrogen or water, which are impurities, while compensating for oxygen deficiency. Therefore, the electrical characteristics of the transistor 200 can be improved, and the variation in the electrical characteristics can be reduced.

[0339] Subsequently, an insulator 282 is formed on the insulator 280 (FIG. 22(C)). The insulator 282 is preferably formed by a sputtering apparatus. By using the sputtering method, an excess oxygen region can be easily formed in the insulator 280, which is the lower layer of the insulator 282.

[0340] During film formation by the sputtering method, ions and sputtered particles exist between the target and the substrate. For example, the target is connected to a power supply and a potential E0 is applied. The substrate is applied with a potential E1 such as a ground potential. However, the substrate may be electrically floating. Also, a region with a potential E2 exists between the target and the substrate. The magnitude relationship of each potential is E2 > E1 > E0.

[0341] Ions in the plasma are accelerated by the potential difference E2 - E0 and collide with the target, whereby particles sputtered from the target are ejected. These sputtered particles adhere to and deposit on the film formation surface, thereby forming a film. Also, some ions are rebounded by the target and may be incorporated into the insulator 280 below the formed film through the film formed as rebounded ions. In addition, ions in the plasma are accelerated by the potential difference E2 - E1 and impact the film formation surface. At this time, some of the ions reach inside the insulator 280. When ions are incorporated into the insulator 280, the ions ​​​​​​​The captured region is formed in the insulator 280. That is, when the ions are ions containing oxygen, an excess oxygen region is formed in the insulator 280. When the ions contain oxygen, an excess oxygen region is formed in the insulator 280.

[0342] An excess oxygen region can be formed by introducing excess oxygen into the insulator 280. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced. The excess oxygen in the insulator 280 is supplied to the oxide 230, and the oxygen deficiency in the oxide 230 can be compensated. Here, when conductors 260, 240a, and 240b having high oxidation resistance are used for the conductors in contact with the insulator 280, the excess oxygen in the insulator 280 can be efficiently supplied to the oxide 230 without being absorbed by the conductors 260, 240a, and 240b. Therefore, the electrical characteristics of the transistor 200 can be improved and the variation in the electrical characteristics can be reduced.

[0343] The transistor 200 according to one aspect of the present invention can be manufactured by the above steps.

[0344] As described above, the configurations, methods, etc. shown in the present embodiment can be used in appropriate combination with the configurations, methods, etc. shown in other embodiments and other examples. As described above, the configurations, methods, etc. shown in the present embodiment can be used in appropriate combination with the configurations, methods, etc. shown in other embodiments and other examples.

[0345] (Embodiment 4) In the present embodiment, one form of the semiconductor device will be described with reference to FIGS. 23 to 33.

[0346] [Configuration Example] An example of a semiconductor device (memory device) according to one aspect of the present invention is shown in FIGS. 23 to 30. Note that FIG. 30(A) shows FIGS. 23 to 26 in a circuit diagram. FIG. 29 shows an end portion of the region where the semiconductor device shown in FIGS. 23 to 26 is formed. An example of a semiconductor device (memory device) according to one aspect of the present invention is shown in FIGS. 23 to 30. Note that FIG. 30(A) shows FIGS. 23 to 26 in a circuit diagram. FIG. 29 shows an end portion of the region where the semiconductor device shown in FIGS. 23 to 26 is formed. An example of a semiconductor device (memory device) according to one aspect of the present invention is shown in FIGS. 23 to 30. Note that FIG. 30(A) shows FIGS. 23 to 26 in a circuit diagram. FIG. 29 shows an end portion of the region where the semiconductor device shown in FIGS. 23 to 26 is formed.

[0347] [Circuit Configuration of Semiconductor Device] The semiconductor devices shown in FIG. 30(A) and FIGS. 23 to 28 include a transistor 300, a transistor 200, and a capacitor element 100.

[0348] The transistor 200 is a transistor in which a channel is formed in a semiconductor layer having an oxide semiconductor. Since the transistor 200 has a small off-current, by using this in a semiconductor device (memory device), it is possible to hold the stored content for a long time. That is, since a refresh operation is not required or the frequency of the refresh operation is extremely low, the power consumption of

[0349] the semiconductor device (memory device) can be sufficiently reduced. In FIG. 30(A), a wiring 3001 is electrically connected to the source of the transistor 300, and a wiring 3002 is electrically connected to the drain of the transistor 300. Also, a wiring 3003 is electrically connected to one of the source and drain of the transistor 200, and a wiring 3004 is electrically connected to the gate of the transistor 200. Then, the gate of the transistor 300 and the other of the source and drain of the transistor 200 are electrically connected to one of

[0350] the electrodes of the capacitor element 100, and a wiring 3005 is electrically connected to the other electrode of the capacitor element 100. 。

[0351] The writing and holding of information will be described. First, the potential of the This sets the transistor 200 to a potential at which it is conductive, thereby making the transistor 200 conductive. The potential of the wiring 3003 is applied to the gate of the transistor 300 and the electrode of the capacitor 100. That is, the gate of the transistor 300 is electrically connected to a node FG. A certain charge is applied to the memory cell (write). Here, two different potential levels are applied. Either the low-level charge or the high-level charge is given. After that, the potential of the wiring 3004 is set to a potential at which the transistor 200 is turned off. By setting the transistor 200 in a non-conductive state, a charge is held at the node FG. will be held (retained).

[0352] When the off-state current of the transistor 200 is small, the charge of the node FG is held for a long period of time. will be done.

[0353] Next, reading of information will be described. When a predetermined potential (constant potential) is applied to the wiring 3001, In this state, when an appropriate potential (read potential) is applied to the wiring 3005, the wiring 3002 becomes a node The potential depends on the amount of charge held in the FG. This is because the transistor 300 is an n-channel When a high-level charge is applied to the gate of the transistor 300, Apparent threshold voltage V th_H A low-level charge is applied to the gate of the transistor 300. The apparent threshold voltage V th_L This is because the Here, the apparent threshold voltage is the voltage required to make the transistor 300 "conductive". Therefore, the potential of the wiring 3005 is V th_ H and V th_LBy setting the potential between them to V0, the charge applied to node FG can be discriminated. For example, in writing, when a high-level charge is applied to node FG, if the potential of wiring 3005 becomes V0 (> V th_H ), transistor 300 will be in the "conducting state". On the other hand, when a low-level charge is applied to node FG, even if the potential of wiring 3005 becomes V0 (< V ), transistor 300 remains in the "non-conducting state". Therefore, by discriminating the potential of wiring 3002, the information held in node FG can be read out. th_L

[0354] Also, by arranging the semiconductor devices shown in Fig. 30(A) in a matrix, a memory device (memory cell array) can be configured.

[0355] When arranging the memory cells in an array, during reading, the information of the desired memory cell must be read out. For example, when transistor 300 is of p-channel type, the memory cell has a NOR-type configuration. Therefore, in memory cells from which information is not read, a potential such that transistor 300 becomes in the "non-conducting state" regardless of the charge applied to node FG, that is, a potential lower than V is applied to wiring 3005 to read only the information of the desired memory cell. Or, when transistor 300 is of n-channel type, the memory cell has a NAND-type configuration. Therefore, in memory cells from which information is not read, th_H a potential such that transistor 300 becomes in the "conducting state" regardless of the charge applied to node FG, that is, a potential higher than V is applied to wiring 3005 to read only the information of the desired memory cell. th_L Only the information of the memory cell can be read out.

[0356] <Circuit configuration 2 of semiconductor device> The semiconductor device shown in FIG. 30(B) is different from the semiconductor device shown in FIG. 30(A) in that it does not have the transistor 300. Also in this case, the writing and holding operations of information are possible by the same operation as the semiconductor device shown in FIG. 30(A). The writing and holding operations of information are possible by the same operation as the semiconductor device shown in FIG. 30(A). The writing and holding operations of information are possible by the same operation as the semiconductor device shown in FIG. 30(A).

[0357] The information reading in the semiconductor device shown in FIG. 30(B) will be described. When the transistor 200 becomes conductive, the floating wiring 3003 and the capacitor element 100 become conductive, and the charge is redistributed between the wiring 3003 and the capacitor element 100. As a result, the potential of the wiring 3003 changes. The amount of change in the potential of the wiring 3003 takes different values depending on the potential of one of the electrodes of the capacitor element 100 (or the charge stored in the capacitor element 100). When the transistor 200 becomes conductive, the floating wiring 3003 and the capacitor element 100 become conductive, and the charge is redistributed between the wiring 3003 and the capacitor element 100. As a result, the potential of the wiring 3003 changes. The amount of change in the potential of the wiring 3003 takes different values depending on the potential of one of the electrodes of the capacitor element 100 (or the charge stored in the capacitor element 100). When the transistor 200 becomes conductive, the floating wiring 3003 and the capacitor element 100 become conductive, and the charge is redistributed between the wiring 3003 and the capacitor element 100. As a result, the potential of the wiring 3003 changes. The amount of change in the potential of the wiring 3003 takes different values depending on the potential of one of the electrodes of the capacitor element 100 (or the charge stored in the capacitor element 100). The amount of change in the potential of the wiring 3003 takes different values depending on the potential of one of the electrodes of the capacitor element 100 (or the charge stored in the capacitor element 100). The amount of change in the potential of the wiring 3003 takes different values depending on the potential of one of the electrodes of the capacitor element 100 (or the charge stored in the capacitor element 100).

[0358] For example, assuming that one of the electrodes of the capacitor element 100 has a potential of V, the capacitance of the capacitor element 100 is C, the capacitance component of the wiring 3003 is CB, and the potential of the wiring 3003 before the charge redistribution is VB0, the potential of the wiring 3003 after the charge redistribution is (CB×VB0 + CV) / (CB + C). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). For example, assuming that one of the electrodes of the capacitor element 100 has a potential of V, the capacitance of the capacitor element 100 is C, the capacitance component of the wiring 3003 is CB, and the potential of the wiring 3003 before the charge redistribution is VB0, the potential of the wiring 3003 after the charge redistribution is (CB×VB0 + CV) / (CB + C). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). For example, assuming that one of the electrodes of the capacitor element 100 has a potential of V, the capacitance of the capacitor element 100 is C, the capacitance component of the wiring 3003 is CB, and the potential of the wiring 3003 before the charge redistribution is VB0, the potential of the wiring 3003 after the charge redistribution is (CB×VB0 + CV) / (CB + C). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)). Therefore, assuming that the state of the memory cell takes two states where the potential of one of the electrodes of the capacitor element 100 is V1 and V0 (V1 > V0), the potential of the wiring 3003 when holding the potential V1 (=(CB×VB0 + CV1) / (CB + C)) is higher than the potential of the wiring 3003 when holding the potential V0 (=(CB×VB0 + CV0) / (CB + C)).

[0359] And by comparing the potential of the wiring 3003 with a predetermined potential, the information can be read out. It is.

[0360] In the case of this configuration, for example, a transistor to which silicon is applied in a drive circuit for driving a memory cell is used, and as the transistor 200, a transistor to which an oxide semiconductor is applied is stacked and arranged on the drive circuit. It is sufficient to use a transistor to which silicon is applied in a drive circuit for driving a memory cell, and as the transistor 200, a transistor to which an oxide semiconductor is applied is stacked and arranged on the drive circuit. It is sufficient to use a transistor to which silicon is applied in a drive circuit for driving a memory cell, and as the transistor 200, a transistor to which an oxide semiconductor is applied is stacked and arranged on the drive circuit.

[0361] The semiconductor device shown above can retain the stored content over a long period of time by applying a transistor with a small off-current using an oxide semiconductor. That is, the refresh operation becomes unnecessary or the frequency of the refresh operation can be made extremely low, so that a semiconductor device with low power consumption can be realized. Also, even in the case where there is no power supply (however, it is preferable that the potential is fixed), the stored content can be retained over a long period of time. The semiconductor device shown above can retain the stored content over a long period of time by applying a transistor with a small off-current using an oxide semiconductor. That is, the refresh operation becomes unnecessary or the frequency of the refresh operation can be made extremely low, so that a semiconductor device with low power consumption can be realized. Also, even in the case where there is no power supply (however, it is preferable that the potential is fixed), the stored content can be retained over a long period of time. The semiconductor device shown above can retain the stored content over a long period of time by applying a transistor with a small off-current using an oxide semiconductor. That is, the refresh operation becomes unnecessary or the frequency of the refresh operation can be made extremely low, so that a semiconductor device with low power consumption can be realized. Also, even in the case where there is no power supply (however, it is preferable that the potential is fixed), the stored content can be retained over a long period of time. The semiconductor device shown above can retain the stored content over a long period of time by applying a transistor with a small off-current using an oxide semiconductor. That is, the refresh operation becomes unnecessary or the frequency of the refresh operation can be made extremely low, so that a semiconductor device with low power consumption can be realized. Also, even in the case where there is no power supply (however, it is preferable that the potential is fixed), the stored content can be retained over a long period of time. The semiconductor device shown above can retain the stored content over a long period of time by applying a transistor with a small off-current using an oxide semiconductor. That is, the refresh operation becomes unnecessary or the frequency of the refresh operation can be made extremely low, so that a semiconductor device with low power consumption can be realized. Also, even in the case where there is no power supply (however, it is preferable that the potential is fixed), the stored content can be retained over a long period of time. The semiconductor device shown above can retain the stored content over a long period of time by applying a transistor with a small off-current using an oxide semiconductor. That is, the refresh operation becomes unnecessary or the frequency of the refresh operation can be made extremely low, so that a semiconductor device with low power consumption can be realized. Also, even in the case where there is no power supply (however, it is preferable that the potential is fixed), the stored content can be retained over a long period of time.

[0362] Also, since a high voltage is not required for writing information in the semiconductor device, element degradation is less likely to occur. For example, unlike a conventional non-volatile memory, since electrons are not injected into or extracted from the floating gate, problems such as degradation of the insulator do not occur. That is, the semiconductor device according to one aspect of the present invention is a semiconductor device with no limit on the number of rewritable times and a dramatically improved reliability, which is different from a conventional non-volatile memory. Also, since a high voltage is not required for writing information in the semiconductor device, element degradation is less likely to occur. For example, unlike a conventional non-volatile memory, since electrons are not injected into or extracted from the floating gate, problems such as degradation of the insulator do not occur. That is, the semiconductor device according to one aspect of the present invention is a semiconductor device with no limit on the number of rewritable times and a dramatically improved reliability, which is different from a conventional non-volatile memory. Also, since a high voltage is not required for writing information in the semiconductor device, element degradation is less likely to occur. For example, unlike a conventional non-volatile memory, since electrons are not injected into or extracted from the floating gate, problems such as degradation of the insulator do not occur. That is, the semiconductor device according to one aspect of the present invention is a semiconductor device with no limit on the number of rewritable times and a dramatically improved reliability, which is different from a conventional non-volatile memory. Also, since a high voltage is not required for writing information in the semiconductor device, element degradation is less likely to occur. For example, unlike a conventional non-volatile memory, since electrons are not injected into or extracted from the floating gate, problems such as degradation of the insulator do not occur. That is, the semiconductor device according to one aspect of the present invention is a semiconductor device with no limit on the number of rewritable times and a dramatically improved reliability, which is different from a conventional non-volatile memory. Also, since a high voltage is not required for writing information in the semiconductor device, element degradation is less likely to occur. For example, unlike a conventional non-volatile memory, since electrons are not injected into or extracted from the floating gate, problems such as degradation of the insulator do not occur. That is, the semiconductor device according to one aspect of the present invention is a semiconductor device with no limit on the number of rewritable times and a dramatically improved reliability, which is different from a conventional non-volatile memory. Furthermore, since information is written depending on the conductive state and non-conductive state of the transistor, high-speed operation is possible. Furthermore, since information is written depending on the conductive state and non-conductive state of the transistor, high-speed operation is possible.

[0363] <Structure 1 of Semiconductor Device> As shown in FIG. 23, the semiconductor device according to one aspect of the present invention includes a transistor 300, a transistor It has a capacitor element 100. The transistor 200 is provided above the transistor 300, and the capacitor element 100 is provided above the transistor 300 and the transistor 200. The transistor 300 is provided on a substrate 311 and has a semiconductor region 312 formed of a part of a conductor 316, an insulator 314, and the substrate 311, and low-resistance regions 318a and 318b that function as a source region or a drain region.

[0364] The transistor 300 may be either p-channel type or n-channel type. In a region where a channel of the semiconductor region 312 is formed, a region in the vicinity thereof, a source region, or a low-resistance region 318a or 318b that becomes a drain region, it is preferable to include a semiconductor such as a silicon-based semiconductor, and it is preferable to include single-crystalline silicon. Or, it may be formed of a material having Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), etc. A configuration using silicon in which the effective mass is controlled by applying stress to the crystal lattice and changing the lattice spacing may also be used. Or, by using GaAs and GaAlAs, etc., the transistor 300 may be a HEMT (High Electron Mobility Transistor).

[0365]

[0366] The low-resistance regions 318a and 318b include, in addition to the semiconductor material applied to the semiconductor region 312, an element that imparts n-type conductivity such as arsenic or phosphorus, or an element that imparts p-type conductivity such as boron.

[0367] ​

[0368] The conductor 316 that functions as a gate electrode is a semiconductor material such as silicon containing an element that imparts n-type conductivity such as arsenic or phosphorus, or an element that imparts p-type conductivity such as boron. , A conductive material such as a metal material, an alloy material, or a metal oxide material can be used.

[0369] Note that the threshold voltage can be adjusted by determining the work function according to the material of the conductor. Specifically, it is preferable to use a material such as titanium nitride or tantalum nitride for the conductor. Furthermore, in order to achieve both conductivity and embedding properties, it is preferable to use a metal material such as tungsten or aluminum as a laminate for the conductor, and it is particularly preferable to use tungsten from the viewpoint of heat resistance.

[0370] Note that the transistor 300 shown in FIG. 23 is an example, and the present invention is not limited to its structure, and an appropriate transistor may be used according to the circuit configuration and driving method. Further, when the circuit configuration shown in FIG. 30(B) is adopted, the transistor 300 may not be provided.

[0371] Over the transistor 300, an insulator 320, an insulator 322, an insulator 324, and an insulator 326 are sequentially laminated and provided.

[0372] As the insulator 320, the insulator 322, the insulator 324, and the insulator 326, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, aluminum nitride, etc. may be used.

[0373] The insulator 322 flattens the step generated by the transistor 300 provided below it. It may function as a planarized film for planarization. For example, the upper surface of the insulator 322 may be planarized by a planarization process using a chemical mechanical polishing (CMP) method or the like to enhance flatness. It may be planarized by a planarization process using a chemical mechanical polishing (CMP) method or the like to enhance flatness. It may be planarized by a planarization process using a chemical mechanical polishing (CMP) method or the like to enhance flatness.

[0374] Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less. Also, for the insulator 324, a film having a barrier property that prevents impurities such as hydrogen from diffusing into the region where the transistor 200 is provided from the substrate 311 or the transistor 300 etc. is preferably used. Here, the barrier property means a high oxidation resistance and a function of suppressing the diffusion of impurities typified by oxygen, hydrogen, and water. For example, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property may be 50 nm or less. Preferably, in an atmosphere of 350 °C or 400 °C, the diffusion distance of oxygen or hydrogen per hour in the film having a barrier property is 30 nm or less, and more preferably 20 nm or less.

[0375] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption. As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption. As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption. As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption. As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption. As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption.

[0376] The amount of hydrogen desorption is, for example, measured by thermal desorption spectroscopy (TDS). It can be analyzed using, for example, In the TDS analysis, the amount of hydrogen desorbed from the insulator 324 is in the range of 50°C to 500°C, and the desorbed amount converted to hydrogen atoms, 1 5 per unit area of the insulator 324, is preferably 10×10 2 or less, and more preferably 5×10 15 or less 2 in terms of atoms / cm .

[0377] Note that the insulator 326 preferably has a lower dielectric constant than the insulator 324. For example, the relative dielectric constant of the insulator 324 is preferably less than 4, and more preferably less than 3. Also, for example, the relative dielectric constant of the insulator 326 is preferably 0.7 times or less, and more preferably 0.6 times or less of the relative dielectric constant of the insulator 324. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between the wirings can be reduced .

[0378] In addition, the insulators 320, 322, 324, and 326 have a capacitor element 1 00, or conductors 328 and 330 electrically connected to the transistor 200 embedded therein. Note that the conductors 328 and 330 function as plugs or wirings . Also, as will be described later, conductors that function as plugs or wirings may be given the same reference numeral when a plurality of structures are grouped together. In this specification, etc., a wiring and a plug electrically connected to the wiring may be an integral body. That is, in some cases, a part of the conductor functions as a wiring, and in some cases, a part of the conductor functions as a plug .

[0379] The materials for each plug and wiring (the conductor 328, the conductor 330, etc.) are metal materials. Conductive materials such as metal alloys, metal nitrides, or metal oxides are applied as single layers or They can be used in layers. Materials such as tungsten and molybdenum that are both heat-resistant and conductive are used. It is preferable to use a high melting point material such as tungsten. It is preferable to form the conductive layer from a low-resistance conductive material such as aluminum or copper. By using this, the wiring resistance can be reduced.

[0380] A wiring layer may be provided on the insulator 326 and the conductor 330. For example, in FIG. An insulator 350, an insulator 352, and an insulator 354 are stacked in this order. In addition, a conductor 356 is formed on the insulators 350, 352, and 354. The conductor 356 functions as a plug or a wiring. The conductive material 328 and the conductive material 330 can be formed using similar materials.

[0381] For example, the insulator 350 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator. In addition, the conductor 356 has a barrier property against hydrogen. In particular, the insulator 350 has a barrier property against hydrogen. A conductor having a barrier property against hydrogen is formed in the opening. The transistor 300 and the transistor 200 can be separated by a barrier layer. This makes it possible to suppress the diffusion of hydrogen from the resistor 300 to the transistor 200.

[0382] As a conductor having a barrier property against hydrogen, for example, tantalum nitride or the like is used. is preferable. Further, by laminating tantalum nitride and highly conductive tungsten, it is possible to suppress the diffusion of hydrogen from the transistor 300 while maintaining the conductivity of the wiring. In this case, it is preferable that the tantalum nitride layer having a barrier property against hydrogen is in contact with the insulator 350 having a barrier property against hydrogen. On the insulator 354, an insulator 358, an insulator 210, an insulator 212, an insulator 213, an insulator 214, and an insulator 216 are laminated in this order. Any of the insulator 358, the insulator

[0383] 210, the insulator 212, the insulator 213, the insulator 214, and the insulator 216 is preferably made of a material having a barrier property against oxygen and hydrogen. For example, for the insulator 358 and the insulator 212, for example, from the region where the substrate 311 or the transistor 300 is provided, a film having a barrier property such that impurities such as hydrogen do not diffuse into the region where the transistor 200 is provided is preferably used. Therefore, the same material as that of the insulator 32 4 can be used.

[0384] As an example of the film having a barrier property against hydrogen, silicon nitride formed by CVD can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 200, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 200 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption.

[0385]

[0386] ​​​​​​​Also, as the film having barrier properties against hydrogen, for example, for the insulator 213 and the insulator 2 14, metal oxides such as aluminum oxide, hafnium oxide, and tantalum oxide are preferably used. This is preferable.

[0387] In particular, aluminum oxide has a high blocking effect of preventing the film from permeating both oxygen and impurities such as hydrogen and moisture, which are factors causing fluctuations in the electrical characteristics of transistors. Therefore, aluminum oxide can prevent the entry of impurities such as hydrogen and moisture into the transistor 200 during and after the manufacturing process of the transistor. Also, it can suppress the release of oxygen from the oxides constituting the transistor 200. Therefore, it is suitable for use as a protective film for the transistor 200.

[0388] Also, for example, the insulator 210 and the insulator 216 can use the same materials as the insulator 320. Also, by using a material with a relatively low dielectric constant as the interlayer film, the parasitic capacitance generated between the wirings can be reduced. For example, as the insulator 216, a silicon oxide film, a silicon oxynitride film, etc. can be used.

[0389] Also, in the insulator 358, the insulator 210, the insulator 212, the insulator 213, the insulator 214, and the insulator 216, conductors such as the conductor 218 and the conductors (conductors 205) constituting the transistor 200 are embedded. Note that the conductor 218 has a function as a plug electrically connected to the capacitor element 100 or the transistor 300, or as a wiring. The conductor 21 8 can be provided using the same materials as the conductor 328 and the conductor 330.

[0390] In particular, in the regions in contact with insulator 358, insulator 212, insulator 213, and insulator 214 conductor 218 is preferably a conductor having barrier properties against oxygen, hydrogen, and water. With this configuration, transistor 300 and transistor 200 can be completely separated by a layer having barrier properties against oxygen, hydrogen, and water, and diffusion of hydrogen from transistor 300 to transistor 200 can be suppressed.

[0391] For example, when insulator 224 has an excess oxygen region, a conductor with high oxidation resistance may be used for conductors in contact with insulator 224, such as conductor 218. Also, as shown in the figure, a conductor 219 having barrier properties may be provided on conductor 218 and the conductor (conductor 205) constituting transistor 200. With this configuration, it is possible to suppress conductor 218 and the conductor (conductor 205) constituting transistor 200 from reacting with oxygen in the excess oxygen region to generate oxides.

[0392] Transistor 200 is provided above insulator 224. Note that the structure of transistor 200 may be the transistor described in the above embodiment. Also, the transistor 200 shown in FIG. 23 is an example, and the structure is not limited thereto; an appropriate transistor may be used according to the circuit configuration and driving method.

[0393] Insulator 280 is provided above transistor 200. It is preferable that an excess oxygen region is formed in insulator 280. In particular, when an oxide semiconductor is used for transistor 200, an insulator having an excess oxygen region may be provided in an interlayer film or the like near transistor 200. As a result, the oxygen vacancies in the transistor 200 can be reduced, thereby improving the reliability. do.

[0394] As an insulator having an excess oxygen region, specifically, an oxide film in which some oxygen is released by heating is used. It is preferable to use materials that release oxygen when heated. , the amount of oxygen released in terms of oxygen atoms is 1.0 × 10 18 atoms / cm 3 Above, I like Or 3.0×10 20 atoms / cm 3 The oxide film is as above. The surface temperature of the membrane during the S analysis is 100°C or higher and 700°C or lower, or 100°C or higher. A range of 500° C. or less is preferred.

[0395] For example, such a material may include silicon oxide or silicon oxynitride. It is preferable to use a metal oxide. Silicon oxynitride refers to a material that contains more oxygen than nitrogen in its composition. Silicon oxide refers to a material whose composition contains more nitrogen than oxygen.

[0396] The insulator 280 covering the transistor 200 is a planarizing layer that covers the uneven surface underneath. The insulator 280 may function as a membrane. The insulator 280 may also have conductors 244 and the like embedded therein. .

[0397] The conductor 244 is connected to the capacitor 100, the transistor 200, or the transistor 300. The conductor 244 functions as a plug or wiring for electrically connecting. , and may be formed using a material similar to that of the conductor 330.

[0398] For example, when the conductor 244 is provided in a laminated structure, it preferably includes a conductor that is difficult to oxidize (has high oxidation resistance). In particular, it is preferable to provide a conductor with high oxidation resistance in a region in contact with the insulator 280 having an excess oxygen region. With this configuration, it is possible to suppress the absorption of excess oxygen from the insulator 280 by the conductor 244. Further, the conductor 244 preferably includes a conductor having a barrier property against hydrogen. In particular, by providing a conductor having a barrier property against impurities such as hydrogen in a region in contact with the insulator 280 having an excess oxygen region, it is possible to suppress impurities in the conductor 244, diffusion of a part of the conductor 244, and the formation of a diffusion path for external impurities. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. The conductor 246, the conductor 124, the conductor 112a, and the conductor 112b include a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above-described elements as components (titanium nitride film). For example, when the conductor 244 is provided in a laminated structure, it preferably includes a conductor that is difficult to oxidize (has high oxidation resistance). In particular, it is preferable to provide a conductor with high oxidation resistance in a region in contact with the insulator 280 having an excess oxygen region. With this configuration, it is possible to suppress the absorption of excess oxygen from the insulator 280 by the conductor 244. Further, the conductor 244 preferably includes a conductor having a barrier property against hydrogen. In particular, by providing a conductor having a barrier property against impurities such as hydrogen in a region in contact with the insulator 280 having an excess oxygen region, it is possible to suppress impurities in the conductor 244, diffusion of a part of the conductor 244, and the formation of a diffusion path for external impurities. For example, when the conductor 244 is provided in a laminated structure, it preferably includes a conductor that is difficult to oxidize (has high oxidation resistance). In particular, it is preferable to provide a conductor with high oxidation resistance in a region in contact with the insulator 280 having an excess oxygen region. With this configuration, it is possible to suppress the absorption of excess oxygen from the insulator 280 by the conductor 244. Further, the conductor 244 preferably includes a conductor having a barrier property against hydrogen. In particular, by providing a conductor having a barrier property against impurities such as hydrogen in a region in contact with the insulator 280 having an excess oxygen region, it is possible to suppress impurities in the conductor 244, diffusion of a part of the conductor 244, and the formation of a diffusion path for external impurities. For example, when the conductor 244 is provided in a laminated structure, it preferably includes a conductor that is difficult to oxidize (has high oxidation resistance). In particular, it is preferable to provide a conductor with high oxidation resistance in a region in contact with the insulator 280 having an excess oxygen region. With this configuration, it is possible to suppress the absorption of excess oxygen from the insulator 280 by the conductor 244. Further, the conductor 244 preferably includes a conductor having a barrier property against hydrogen. In particular, by providing a conductor having a barrier property against impurities such as hydrogen in a region in contact with the insulator 280 having an excess oxygen region, it is possible to suppress impurities in the conductor 244, diffusion of a part of the conductor 244, and the formation of a diffusion path for external impurities. For example, when the conductor 244 is provided in a laminated structure, it preferably includes a conductor that is difficult to oxidize (has high oxidation resistance). In particular, it is preferable to provide a conductor with high oxidation resistance in a region in contact with the insulator 280 having an excess oxygen region. With this configuration, it is possible to suppress the absorption of excess oxygen from the insulator 280 by the conductor 244. Further, the conductor 244 preferably includes a conductor having a barrier property against hydrogen. In particular, by providing a conductor having a barrier property against impurities such as hydrogen in a region in contact with the insulator 280 having an excess oxygen region, it is possible to suppress impurities in the conductor 244, diffusion of a part of the conductor 244, and the formation of a diffusion path for external impurities. For example, when the conductor 244 is provided in a laminated structure, it preferably includes a conductor that is difficult to oxidize (has high oxidation resistance). In particular, it is preferable to provide a conductor with high oxidation resistance in a region in contact with the insulator 280 having an excess oxygen region. With this configuration, it is possible to suppress the absorption of excess oxygen from the insulator 280 by the conductor 244. Further, the conductor 244 preferably includes a conductor having a barrier property against hydrogen. In particular, by providing a conductor having a barrier property against impurities such as hydrogen in a region in contact with the insulator 280 having an excess oxygen region, it is possible to suppress impurities in the conductor 244, diffusion of a part of the conductor 244, and the formation of a diffusion path for external impurities.

[0399] Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously. Further, a conductor 246, a conductor 124, a conductor 112a, and a conductor 112b may be provided on the conductor 244. The conductor 246 and the conductor 124 function as a plug or wiring electrically connected to the capacitor element 100, the transistor 200, or the transistor 300. Further, the conductor 112a and the conductor 112b function as electrodes of the capacitor element 100. Note that the conductor 246 and the conductor 112a can be formed simultaneously. Also, the conductor 124 and the conductor 112b can be formed simultaneously.

[0400] The conductor 246, the conductor 124, the conductor 112a, and the conductor 112b include a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above-described elements as components (titanium nitride film). The conductor 246, the conductor 124, the conductor 112a, and the conductor 112b include a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above-described elements as components (titanium nitride film). The conductor 246, the conductor 124, the conductor 112a, and the conductor 112b include a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above-described elements as components (titanium nitride film). It is possible to use an interlayer film, a titanium nitride film, a molybdenum nitride film, a tungsten nitride film, etc. Or, it is also possible to apply a conductive material such as indium tin oxide, 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, or indium tin oxide added with silicon oxide. In particular, the conductor 246 and the conductor 112a preferably have a barrier property against hydrogen or oxygen and are difficult to oxidize (high oxidation resistance). On the other hand, for the conductor 124 and the conductor 112b, for example, a material having high conductivity such as tungsten may be laminated. By using such a combination, it is possible to suppress the diffusion of hydrogen to the insulator 280 and the transistor 200 while maintaining the conductivity as a wiring. In FIG. 23, a two-layer structure of the conductor 246 and the conductor 124 is shown, but the present invention is not limited to this configuration, and a single layer or a laminated structure of three or more layers may be used. For example, a conductor having a barrier property, and a conductor having high adhesion to a conductor having high conductivity may be formed between a conductor having a barrier property and a conductor having high conductivity. Also, a barrier layer 281 may be provided on the conductor 124. By having the barrier layer 281, it is possible to suppress the oxidation of the conductor 124 in a subsequent process. Further, it is possible to suppress the diffusion of impurities contained in the conductor 124 and a part of the conductor 124. Further, it is possible to suppress the diffusion of impurities to the insulator 280 through the conductor 124, the conductor 246, and the conductor 244. It is possible to use an interlayer film, a titanium nitride film, a molybdenum nitride film, a tungsten nitride film, etc. Or, it is also possible to apply a conductive material such as indium tin oxide, 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, or indium tin oxide added with silicon oxide. It is possible to use an interlayer film, a titanium nitride film, a molybdenum nitride film, a tungsten nitride film, etc. Or, it is also possible to apply a conductive material such as indium tin oxide, 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, or indium tin oxide added with silicon oxide.

[0401] In particular, the conductor 246 and the conductor 112a preferably have a barrier property against hydrogen or oxygen and are difficult to oxidize (high oxidation resistance). On the other hand, for the conductor 124 and the conductor 112b, for example, a material having high conductivity such as tungsten may be laminated. By using such a combination, it is possible to suppress the diffusion of hydrogen to the insulator 280 and the transistor 200 while maintaining the conductivity as a wiring. In FIG. 23, a two-layer structure of the conductor 246 and the conductor 124 is shown, but the present invention is not limited to this configuration, and a single layer or a laminated structure of three or more layers may be used. For example, a conductor having a barrier property, and a conductor having high adhesion to a conductor having high conductivity may be formed between a conductor having a barrier property and a conductor having high conductivity. In particular, the conductor 246 and the conductor 112a preferably have a barrier property against hydrogen or oxygen and are difficult to oxidize (high oxidation resistance). On the other hand, for the conductor 124 and the conductor 112b, for example, a material having high conductivity such as tungsten may be laminated. By using such a combination, it is possible to suppress the diffusion of hydrogen to the insulator 280 and the transistor 200 while maintaining the conductivity as a wiring. In FIG. 23, a two-layer structure of the conductor 246 and the conductor 124 is shown, but the present invention is not limited to this configuration, and a single layer or a laminated structure of three or more layers may be used. For example, a conductor having a barrier property, and a conductor having high adhesion to a conductor having high conductivity may be formed between a conductor having a barrier property and a conductor having high conductivity. In particular, the conductor 246 and the conductor 112a preferably have a barrier property against hydrogen or oxygen and are difficult to oxidize (high oxidation resistance). On the other hand, for the conductor 124 and the conductor 112b, for example, a material having high conductivity such as tungsten may be laminated. By using such a combination, it is possible to suppress the diffusion of hydrogen to the insulator 280 and the transistor 200 while maintaining the conductivity as a wiring. In FIG. 23, a two-layer structure of the conductor 246 and the conductor 124 is shown, but the present invention is not limited to this configuration, and a single layer or a laminated structure of three or more layers may be used. For example, a conductor having ...

Claims

1. A gate electrode; A gate insulating film; an oxide semiconductor containing indium, an element M, and zinc; The element M has one or more of Al, Ga, Y, or Sn, the oxide semiconductor has a first region and a second region in which indium is present at a higher concentration than in the first region; The second region is interspersed within the first region.

2. A gate electrode; A gate insulating film; an oxide semiconductor containing indium, an element M, and zinc; The element M has one or more of Al, Ga, Y, or Sn, the oxide semiconductor has a first region and a second region in which indium is present at a concentration that is 1.1 times or more and 10 times or less than that of the first region; The second region is interspersed within the first region.

3. A gate electrode; A gate insulating film; an oxide semiconductor containing indium, an element M, and zinc; The element M has one or more of Al, Ga, Y, or Sn, the oxide semiconductor has a first region and a second region in which indium is present at a higher concentration than in the first region; The second region is contained within the first region.

4. A gate electrode; A gate insulating film; an oxide semiconductor containing indium, an element M, and zinc; The element M has one or more of Al, Ga, Y, or Sn, the oxide semiconductor has a first region and a second region in which indium is present at a concentration that is 1.1 times or more and 10 times or less than that of the first region; The second region is contained within the first region.

5. In any one of claims 1 to 4, The first region has a different crystal structure than the second region.

6. In any one of claims 1 to 5, The second region is non-single crystalline.

7. In any one of claims 1 to 6, The first region is polycrystalline.

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