Device and method for producing the same

Abstract

To provide a semiconductor device including an inorganic light-emitting element.SOLUTION: A semiconductor device includes an inorganic light-emitting element, a transistor, and a capacitor. The inorganic light-emitting element includes a first film and a second film. The first film contains indium, oxygen, and nitrogen, and the second film contains gallium and nitrogen. The first film has a wurtzite structure or a cubic crystal structure, and the second film has a wurtzite structure and grows on the first film. The first film functions as a cathode electrode of the inorganic light-emitting element. One electrode of the capacitor is formed above the second film included in the inorganic light-emitting element, and a transistor including a metal oxide in a semiconductor layer is formed above the other electrode of the capacitor. The one electrode of the capacitor has a function of reflecting light emitted from the inorganic light-emitting element. The inorganic light-emitting element emits light through the first film.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One aspect of the present invention relates to a semiconductor device using a metal nitride film and a metal nitride film formed on a metal oxynitride film. Further, one aspect of the present invention relates to an inorganic light-emitting element, a lighting device, a display device, an electronic device, and a semiconductor device using the metal nitride film.

[0002] 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 storage devices are one aspect of semiconductor devices. Display devices (such as liquid crystal display devices and light-emitting display devices), projection devices, lighting devices, electro-optical devices, power storage devices, storage devices, semiconductor circuits, imaging devices, communication devices, and electronic devices may be said to have semiconductor devices.

[0003] Note that one aspect of the present invention is not limited to the above technical field. One aspect of the invention disclosed in this specification and the like relates to an article, a method, or a manufacturing method. Further, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter.

Background Art

[0004] Nitride semiconductors containing group 13 elements (such as gallium) are known as constituent materials for inorganic light-emitting elements, power semiconductor elements, or communication devices. Patent Document 1 discloses a method for manufacturing a nitride semiconductor.

[0005] Metal oxynitrides having metal, oxygen, and nitrogen are known as pigments and photocatalyst materials. Further, metal oxynitrides have also attracted attention as semiconductor materials and insulating materials used in semiconductor devices and the like. Patent Document 2 discloses a semiconductor material having a metal oxynitride containing indium, gallium, and zinc.

[0006] Also, as one of the methods for forming a thin film with in-plane orientation (also referred to as a single-crystalline thin film), an epitaxial growth method is known. Here, in-plane orientation refers to the regularity of the crystal orientation in the horizontal direction with respect to the substrate. In Patent Document 3, a method for forming a single-crystalline InGaO3(ZnO)5 thin film by a reactive solid-phase epitaxial method is disclosed.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] In the method for producing a nitride semiconductor disclosed in Patent Document 1, it is produced using the pulsed laser deposition (PLD) method. The PLD method is a film-forming method that utilizes laser ablation and requires a laser and an optical system. Also, there is a problem that a large difference occurs in the film deposition rate between the front surface of the plasma (plume) induced in the target by laser irradiation and other parts. Therefore, it is difficult to produce a large amount of thin film using the PLD method.

[0009] Moreover, the state of the metal oxynitride disclosed in Patent Document 2 is an amorphous state in which the interatomic bonds are disordered. Since the amorphous metal oxynitride has a loose or low-density region, there is a problem that the stability of the metal oxynitride is low. The metal oxynitride used in semiconductor devices and the like preferably has high crystallinity. In particular, the metal oxynitride preferably has in-plane orientation.

[0010] In the reactive solid-phase epitaxial method disclosed in Patent Document 3, before forming the InGaO3(ZnO)5 thin film, a process of heating the substrate to 1000 °C or higher is performed. After forming the thin film, a heat diffusion process is performed at a temperature of 1300 °C or higher. There is a problem that such high-temperature processes are required. In addition, in order to form a single-crystalline InGaO3(ZnO)5 thin film, it is necessary to provide an epitaxially grown ZnO thin film on the substrate. Thus, there are various restrictions on forming a thin film epitaxially grown using the prior art. In this specification, high temperature refers to, for example, a temperature of 700 °C or higher, and low temperature refers to, for example, a temperature of 600 °C or lower.

[0011] Therefore, one aspect of the present invention is to provide an inorganic light-emitting device using a metal nitride film epitaxially grown and formed on a metal oxynitride film, etc. Another aspect of the present invention is to improve the productivity of an inorganic light-emitting device using a metal nitride film, etc. Another aspect of the present invention is to provide a method for epitaxially growing and forming a metal oxynitride film at a low temperature. Another aspect of the present invention is to provide a method for epitaxially growing and forming the metal oxynitride film without performing a high-temperature process before and after forming the metal oxynitride film. Another aspect of the present invention is to provide a method for epitaxially growing and forming a metal nitride film on a metal oxynitride film without performing a high-temperature process.

[0012] 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. Other problems will naturally become clear from the description in the specification, drawings, claims, etc., and it is possible to extract these other problems from the description in the specification, drawings, claims, etc.

Means for Solving the Problems

[0013] An inorganic light-emitting device according to one aspect of the present invention includes a first film (metal oxynitride film) and a second film (metal nitride film). The first film contains indium and oxygen, and the second film contains gallium and nitrogen. The second film has a wurtzite structure. The first film can function as a cathode electrode of the inorganic light-emitting device. Preferably, the first film further contains gallium, zinc, and nitrogen.

[0014] A semiconductor device according to another aspect of the present invention includes an inorganic light-emitting device, a transistor, and a capacitor. The inorganic light-emitting device includes a first film (metal oxynitride film) and a second film (metal nitride film). The first film contains indium and oxygen, and the second film contains gallium and nitrogen. The second film has a wurtzite structure. One electrode of the capacitor is formed above the second film of the inorganic light-emitting device, and a transistor is formed above the other electrode of the capacitor. One electrode of the capacitor has a function of reflecting light emitted by the inorganic light-emitting device, and the inorganic light-emitting device can emit light through the first film. Further, the transistor has a metal oxide in the semiconductor layer, and preferably, the semiconductor layer of the transistor contains indium, gallium, zinc, and oxygen.

[0015] Another aspect of the present invention is a method for manufacturing the first film. The first film can be epitaxially grown on a substrate by a sputtering method using an oxide target while introducing a gas containing nitrogen gas. Preferably, the first film is a film with in-plane orientation. The oxide target contains zinc and has conductivity. The temperature of the substrate during the film formation of the first film is 80°C or higher and 500°C or lower, and the flow rate of nitrogen gas is 50% or higher and 100% or lower in the total flow rate of the gas. Preferably, the oxide target further contains indium and gallium.

[0016] In the above, the substrate is a single-crystalline yttria-stabilized zirconia (YSZ) substrate, and preferably, the plane orientation of the substrate is (111). Alternatively, the substrate is a single-crystalline a-plane sapphire substrate, and preferably, the plane orientation of the substrate is (110).

[0017] Another aspect of the present invention is a method for forming a second film. The second film can be epitaxially grown on the first film by a sputtering method using a nitride target by introducing a gas containing nitrogen gas. Note that the second film is preferably a film with in-plane orientation. The nitride target contains gallium and nitrogen and has conductivity. The substrate during the formation of the metal nitride film is 80°C or higher and 500°C or lower, and the flow rate of nitrogen gas is 80% or higher and 100% or lower in the total flow rate of the gas.

[0018] In the above, when performing a φ scan in X-ray analysis with respect to the (101) plane of the crystals of the first film and the second film, it is preferable that diffraction peaks showing six-fold symmetry are observed for the first film and the second film. Also, regarding the in-plane orientation, it is considered that the smaller the full width at half maximum (sometimes referred to as Δφ) of the φ scan in X-ray diffraction, the better the in-plane orientation.

Advantages of the Invention

[0019] According to one aspect of the present invention, it is possible to provide an inorganic light-emitting element or the like using a metal nitride film formed by epitaxial growth on a metal oxynitride film. Further, according to one aspect of the present invention, the productivity of an inorganic light-emitting element or the like using a metal nitride film can be increased. Further, according to one aspect of the present invention, it is possible to provide a method for forming a metal oxynitride film by epitaxial growth at a low temperature. Further, according to one aspect of the present invention, it is possible to provide a method for epitaxially growing and forming the metal oxynitride film without performing a high-temperature treatment before and after the formation of the metal oxynitride film. Further, one aspect of the present invention can provide a method for epitaxially growing and forming a metal nitride film on a metal oxynitride film without performing a high-temperature treatment.

[0020] Note that the description of these effects does not preclude 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 become 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

[0021]

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[0022] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different modes, and it is easily understood by those skilled in the art that the forms and details can be variously changed without departing from the spirit and its scope. Therefore, the present invention is not construed as being limited to the description of the following embodiments.

[0023] Also, in the drawings, the size, layer thickness, or region may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale. Note that the drawings schematically show ideal examples and are not limited to the shapes or values shown in the drawings. For example, in an actual manufacturing process, layers, resist masks, etc. may be unintentionally thinned by processes such as etching, but may not be reflected in the drawings for ease of understanding. Also, in the drawings, the same reference numerals are commonly used between different drawings for the same part or parts having the same function, and repeated description thereof may be omitted. Also, when referring to the same function, the hatch pattern may be the same and may not be particularly labeled.

[0024] Also, especially in a top view (also referred to as a "plan view") or a perspective view, etc., for ease of understanding of the invention, the description of some components may be omitted. Also, the description of some hidden lines, etc. may be omitted.

[0025] In addition, in this specification and the like, terms indicating arrangements such as "above" and "below" are used for convenience in explaining the positional relationship between components with reference to the drawings. Also, the positional relationship between components changes appropriately according to the direction in which each component is depicted. Therefore, it is not limited to the terms described in the specification, and can be appropriately rephrased according to the situation.

[0026] For example, in this specification and the like, when it is explicitly described that X and Y are connected, it is assumed that what is disclosed in this specification and the like includes the case where X and Y are electrically connected, the case where X and Y are functionally connected, and the case where X and Y are directly connected. Therefore, it is not limited to a predetermined connection relationship, for example, the connection relationship shown in the figure or the text, and those other than the connection relationship shown in the figure or the text are also assumed to be disclosed in the figure or the text. Here, it is assumed that X and Y are objects (for example, devices, elements, circuits, wirings, electrodes, terminals, conductive films, layers, etc.).

[0027] 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 it has a region (hereinafter also referred to as a channel formation region) in which a channel is formed between the drain (drain terminal, drain region, or drain electrode) and the source (source terminal, source region, or source electrode), and current can flow between the source and the drain through the channel formation region. Note that in this specification and the like, the channel formation region refers to the region where current mainly flows.

[0028] Also, the functions of the source and the drain may be interchanged when transistors of different polarities are adopted or when the direction of current changes in the circuit operation. For this reason, in this specification and the like, the terms of the source and the drain may be used interchangeably.

[0029] In addition, in this specification and the like, the term "insulator" can be replaced with "insulating film". Also, the term "conductor" can be replaced with "conductive film". Further, the term "semiconductor" can be replaced with "semiconductor film" or "semiconductor layer".

[0030] In addition, in this specification, "parallel" means a state in which two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, the case of -5° or more and 5° or less is also included. Also, "substantially parallel" means a state in which two straight lines are arranged at an angle of -30° or more and 30° or less. Further, "perpendicular" means a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, the case of 85° or more and 95° or less is also included. Also, "substantially perpendicular" means a state in which two straight lines are arranged at an angle of 60° or more and 120° or less.

[0031] In this specification, crystal planes are represented using Miller indices. Miller indices are indicated by three integers within parentheses. Also, the direction of the arrangement of crystal planes (the direction perpendicular to the crystal planes) is called the crystal orientation. The crystal orientation is indicated by three integers within angle brackets. For example, when representing a crystal plane, it is shown as (111), and when representing a crystal orientation, it is shown as

[0111] . Note that in the hexagonal crystal system, a notation called the Miller - Bravais index may be used. Specifically, the plane indices of a hexagonal lattice are represented as (hkil) using four integers (h, k, i, l). Here, i = -(h + k). Since the index i can be calculated from the values of the indices h and k, in this specification, even for crystal planes in the hexagonal crystal system, they are represented using Miller indices (hkl) with three integers. Also, in crystallography, the notations for crystal planes, directions, and space groups have a bar above the numbers, but in this specification and the like, due to the constraints of the application notation, instead of putting a bar above the numbers, a - (minus sign) may be attached before the numbers for expression.

[0032] In this specification, the crystal plane that appears on the surface of a single - crystal substrate may be referred to as the plane orientation of the single - crystal substrate.

[0033] In this specification, lattice points (also referred to as reciprocal lattice points) in the reciprocal lattice corresponding to crystal planes are represented by indices without parentheses.

[0034] (Embodiment 1) In this embodiment, a method for manufacturing a metal nitride film used for an inorganic light-emitting element, which is one aspect of the present invention, will be described.

[0035] Metal nitrides containing metal and nitrogen have attracted attention as semiconductor materials and insulating materials used in semiconductor devices. It is preferable that the metal nitride used in the semiconductor device has few impurities and defects and high stability. Note that the fact that the metal nitride has few impurities and defects can be rephrased as the metal nitride having high crystallinity. Further, the high stability of the metal nitride means that it is difficult to react with the material in contact with the metal nitride due to heat generation or the like accompanying the operation of the semiconductor device, the crystallinity of the metal nitride does not change, or defects are less likely to occur in the metal nitride, etc. By using a metal nitride having few impurities and defects and high stability in a semiconductor device, the reliability of the semiconductor device can be improved.

[0036] In one aspect of the present invention, in order to produce a highly crystalline metal nitride film with few impurities and defects, a metal oxynitride film can be provided as a buffer layer between the substrate and the metal nitride. In order to produce a highly crystalline metal nitride film, it is preferable to provide a metal oxynitride film with few impurities and defects.

[0037] Impurities in the metal oxynitride refer to, for example, components other than the main components constituting the metal oxynitride. For example, in a metal oxynitride, an element with a concentration of less than 0.1 atomic% can be said to be an impurity. Examples of such elements include hydrogen, silicon, boron, phosphorus, carbon, and transition metals other than the main components constituting the metal oxynitride. Further, defects in the metal oxynitride refer to lattice defects, and examples of lattice defects include point defects such as oxygen deficiency and nitrogen deficiency, line defects such as dislocations, and plane defects such as grain boundaries. In addition, defects in the metal oxynitride include void defects such as porosity.

[0038] In addition, from the perspective of crystallinity, thin films include in-plane oriented thin films, oriented thin films, non-oriented thin films (polycrystalline thin films), amorphous thin films (amorphous thin films), and the like. An oriented thin film is a thin film in which at least one crystal axis is aligned in a specific direction in the crystals contained in the thin film. An in-plane oriented thin film is a thin film in which three crystal axes are aligned in specific directions in the crystals contained in the thin film.

[0039] The thin film of metal oxynitride used in semiconductor devices and the like preferably has orientation, and more preferably is an in-plane oriented thin film of metal oxynitride. The in-plane oriented thin film of metal oxynitride has few impurities and defects and has a dense structure. Therefore, by using the in-plane oriented thin film of metal oxynitride in semiconductor devices and the like, the reliability of the semiconductor devices and the like can be improved.

[0040] Epitaxial growth is known as a method for forming an in-plane oriented thin film. Epitaxial growth means that crystals constituting a thin film grow on a single crystal substrate with a certain crystal orientation relationship. Note that growing a crystal on a single crystal substrate using the same material as the substrate and having the same lattice constant as the crystal of the substrate is called homoepitaxial growth. Also, growing a crystal on a single crystal substrate using a material different from the substrate or a material having a lattice constant different from the lattice constant of the crystal of the substrate is called heteroepitaxial growth. Heteroepitaxial growth can be achieved by selecting a material with a small lattice mismatch with respect to the crystal of the substrate, or by providing a layer (also called a buffer layer) that relaxes the lattice strain between the substrate and the thin film.

[0041] Methods of epitaxial growth include solid phase epitaxial growth (SPE: Solid Phase Epitaxy) method, liquid phase epitaxial growth (LPE: Liquid Phase Epitaxy) method, and vapor phase epitaxial growth (VPE: Vapor Phase Epitaxy) method.

[0042] The SPE method is a method of heating the material deposited on the substrate surface by electron beam irradiation or the like to change the material into the same crystal structure as that of the crystal possessed by the substrate. The LPE method is a method of precipitating crystal parts on the substrate surface from a supersaturated solution. The VPE method is a method of depositing components in the gas phase on the substrate surface. The VPE method includes a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, a molecular beam epitaxy (MBE) method, and the like. The MBE method is a method of heating and evaporating the elements constituting the target crystal or the material containing the elements in an ultra-high vacuum and depositing the crystal on the heated substrate.

[0043] In the prior art, there are various restrictions for epitaxially growing a thin film. Examples of such restrictions include forming the thin film at a high temperature, performing heat treatment at a high temperature (for example, 1000 °C or higher) after forming the thin film, performing a planarization treatment on the substrate surface before forming the thin film, providing one or more buffer layers on the substrate, or selecting a substrate having a lattice constant or a thermal expansion coefficient close to that of the thin film. Examples of the planarization treatment of the substrate surface include performing heat treatment on the substrate at a high temperature.

[0044] Therefore, in the method for producing a metal oxynitride film according to one aspect of the present invention, the metal oxynitride film is epitaxially grown at a low temperature. In this production method, a gas is introduced into a reaction chamber on a single crystal substrate, and a metal oxynitride film is epitaxially grown by a sputtering method. In one aspect of the present invention, a film with in-plane orientation can be formed by epitaxial growth.

[0045] The crystal structure of the metal oxynitride film to be epitaxially grown is preferably a hexagonal crystal structure. Among the hexagonal crystal structures, in particular, a wurtzite structure is preferable. The wurtzite structure has a crystal orientation relationship that enables epitaxial growth with respect to a cubic crystal system (for example, diamond structure, fluorite structure, zinc blende structure, etc.). For example, the

[0111] direction of the cubic crystal and the

[0001] direction of the wurtzite structure have a crystal orientation relationship that enables epitaxial growth. Therefore, it is possible to facilitate the epitaxial growth of a metal oxynitride film having a hexagonal crystal structure on a single crystal substrate having a crystal structure such as a cubic crystal system or a hexagonal crystal system. Also, it is possible to facilitate the epitaxial growth of a material having a crystal structure such as a cubic crystal system or a hexagonal crystal system on the metal oxynitride film.

[0046] In addition to the above-described hexagonal crystal structure, the crystal structure of the metal oxide thin film to be epitaxially grown is preferably a cubic crystal structure. Among the cubic crystal structures, in particular, a bixbyite (C-type rare earth type) structure is preferable. The cubic crystal system has a crystal orientation relationship that enables epitaxial growth with respect to the hexagonal crystal system. As described above, since the

[0111] direction of the cubic crystal and the

[0001] direction of the wurtzite structure have a crystal orientation relationship that enables epitaxial growth, it is possible to facilitate the epitaxial growth of a metal nitride film having a hexagonal crystal structure on the metal oxide thin film having a cubic crystal structure.

[0047] As the single crystal substrate, insulator substrates such as sapphire substrates and stabilized zirconia substrates (such as yttria-stabilized zirconia (YSZ) substrates) can be used. When the crystal structure of the metal oxynitride is the wurtzite structure, as the above substrate, for example, a YSZ substrate with a plane orientation of (111) or an a-plane sapphire substrate with a plane orientation of (110) is preferably used. By using a YSZ substrate or an a-plane sapphire substrate for the above substrate, it becomes easier to form a thin film of metal oxynitride having a wurtzite structure crystal and in-plane orientation. In addition, substrates such as silicon, germanium, silicon carbide, gallium nitride, gallium arsenide, indium phosphide, and zinc oxide may be used.

[0048] The difference (also referred to as lattice mismatch) between the lattice constant of the crystal of the epitaxially grown thin film and the lattice constant of the crystal of the substrate is preferably small. By reducing the lattice mismatch, it becomes possible to easily epitaxially grow a thin film on a single crystal substrate.

[0049] As one method for evaluating the degree of lattice mismatch, there is the lattice mismatch degree. The lattice mismatch degree Δa is the lattice constant a of the crystal of the epitaxially grown thin film e and the lattice constant a of the crystal of the substrate s and is calculated from the following formula (1).

[0050]

Equation

[0051] The lattice mismatch degree between the metal oxynitride film to be epitaxially grown and the single crystal substrate is preferably 15% or less, more preferably 10% or less. Thereby, it becomes possible to easily epitaxially grow a metal oxynitride film on a single crystal substrate.

[0052] In addition, when epitaxially growing a metal oxynitride film having a wurtzite structure crystal on a cubic single crystal substrate, for example, the substrate is in the

[0111] direction and the metal oxynitride film is in the

[0001] direction, and the crystal orientations are different. Therefore, as By setting the value to \(\frac{\sqrt{2}}{2}\) times the lattice constant of the crystal of the substrate, the lattice mismatch can be calculated. Specifically, when using a YSZ substrate with a lattice constant in the a-axis direction of about 0.51 nm as the single-crystal substrate, the nearest-neighbor interatomic distance as viewed from the

[0111] direction is about 0.36 nm at the minimum. Therefore, in view of the preferable range of the lattice mismatch described above, the lattice constant in the a-axis direction of the crystal of the metal oxynitride film is preferably 0.31 nm or more and 0.41 nm or less, and more preferably 0.32 nm or more and 0.40 nm or less.

[0053] Furthermore, in the method for producing a metal nitride film according to one aspect of the present invention, a metal nitride film is epitaxially grown at a low temperature on a metal oxynitride film or a metal oxide film. As an example, when epitaxially growing a metal nitride film at a low temperature on a metal oxynitride film, a gas is introduced into the reaction chamber on the above-described metal oxynitride film, and a metal nitride film is epitaxially grown by a sputtering method. In one aspect of the present invention, a film with in-plane orientation can be formed by epitaxial growth.

[0054] The crystal structure of the metal nitride film to be epitaxially grown is preferably a hexagonal crystal structure. Among the hexagonal crystal structures, in particular, a wurtzite structure is preferable. Since the epitaxially grown metal oxynitride film has a wurtzite structure, it is easy to grow a metal nitride film having a wurtzite structure on the metal oxynitride film.

[0055] For example, a metal nitride film epitaxially grown on a metal oxynitride film epitaxially grown on a YSZ substrate with a plane orientation of (111) or an a-plane sapphire substrate with a plane orientation of (110) has higher crystallinity than a metal nitride film epitaxially grown on a YSZ substrate with a plane orientation of (111) or an a-plane sapphire substrate with a plane orientation of (110). While generally high-temperature conditions are required for epitaxial growth, in this method, high-temperature conditions are not required for epitaxial growth. Also, the metal oxynitride film can be easily formed using a sputtering method.

[0056] Since the epitaxially grown metal oxynitride film has a wurtzite structure, the metal oxynitride film functions as a good buffer layer that relaxes the lattice mismatch between the substrate and the metal nitride film. When the metal oxynitride film and the metal nitride film are used as semiconductor devices, it is preferable that the crystallinity of the metal nitride film is high.

[0057] As an example, when an inorganic light-emitting element is formed using a metal nitride, the metal nitride film has at least an n-type clad layer, an active layer, and a p-type clad layer. Therefore, in order to stack the metal nitride films, it is preferable that the metal nitride film on the buffer layer has higher crystallinity than the buffer layer. By increasing the crystallinity, the uniformity such as the carrier concentration in the metal nitride film is improved, and the electrical characteristics are improved. Furthermore, by increasing the crystallinity, the withstand voltage and the reliability against current of the inorganic light-emitting element can be improved. In Embodiment 2, an example of manufacturing an inorganic light-emitting element or a display device using a metal oxynitride film and a metal nitride film will be described in detail.

[0058] Note that the semiconductor device using the metal oxynitride film and the metal nitride film is not limited to a display element and a display device. The semiconductor device can be applied to a projection device, a lighting device, an electro-optical device, a power storage device, a storage device, a semiconductor circuit, an imaging device, a communication device, or an electronic device.

[0059] A schematic diagram of a structure including a metal oxynitride film epitaxially grown on a single-crystalline substrate is shown in FIG. 1A. FIG. 1A is a schematic diagram of a structure in which a metal oxynitride film 20 is formed on a single-crystalline substrate 10. FIG. 1A illustrates a case where the metal oxynitride film 20 has a crystal 20a with a wurtzite structure. By the manufacturing method of one aspect of the present invention, the metal oxynitride film 20 epitaxially grows so that the c-axis (

[0001] direction) of the crystal 20a with a wurtzite structure coincides with the normal direction of the surface of the single-crystalline substrate 10. Here, since the film epitaxially grown by the manufacturing method of one aspect of the present invention has the c-axis (

[0001] direction) of the crystal contained in the film coinciding with the normal direction of the surface of the single-crystalline substrate, the film epitaxially grown by the manufacturing method of one aspect of the present invention may be referred to as a c-axis epitaxial film. Note that the normal direction may be referred to as the vertical direction.

[0060] The crystal planes of the wurtzite structure will be described with reference to FIG. 1B. FIG. 1B shows typical crystal planes ((001) plane, (101) plane) of the wurtzite structure. The (001) plane of the wurtzite structure shown in FIG. 1B is a plane parallel to the surface of the single-crystalline substrate 10.

[0061] FIG. 1C shows the atomic arrangement in the wurtzite structure. Arrangement X1 in FIG. 1C is the arrangement of metal atoms, and arrangement X2 is the arrangement of oxygen atoms or nitrogen atoms. Note that arrangement X1 may be the arrangement of oxygen atoms or nitrogen atoms, and arrangement X2 may be the arrangement of metal atoms.

[0062] The sputtering target used in the above sputtering method is preferably an oxide target containing zinc, and more preferably an oxide target containing at least one of indium and gallium and zinc. As the oxide target, for example, a zinc oxide target, an indium zinc oxide (In-Zn oxide) target, a gallium zinc oxide (Ga-Zn oxide) target, an indium gallium zinc oxide (In-Ga-Zn oxide) target, etc. can be used. In particular, it is preferable to use an indium gallium zinc oxide target as the oxide target. The crystal structures of indium nitride, gallium nitride, and zinc oxide are all wurtzite-type structures. Therefore, by forming a film using the oxide target, it becomes easy to form a thin film of a metal oxynitride having a wurtzite-type crystal and in-plane orientation. Even when an oxide target that is not of the wurtzite type is used, the formed thin film may have a wurtzite-type structure.

[0063] Also, as a different example, the sputtering target used in the sputtering method is preferably an oxide target containing indium, and more preferably an oxide target containing indium and tin. As the oxide target, for example, an indium oxide target, an indium tin oxide (ITO) target can be used. Usually, the crystal structures of indium oxide and indium tin oxide are both bixbyite (C-type rare earth type) structures. Therefore, by forming a film using the oxide target, it becomes easy to form a thin film of a metal oxide having a bixbyite-type crystal and in-plane orientation.

[0064] FIG. 2 shows a schematic diagram of a structure including a metal nitride film 30 epitaxially grown on a metal oxynitride film 20 having a wurtzite structure. The metal nitride film 30 has crystals 30a having a wurtzite-type structure. Note that the (001) plane of the wurtzite-type structure of the metal oxynitride film 20 is a plane parallel to the crystal plane on which the metal nitride film 30 epitaxially grows, so that the crystallinity of the metal nitride film 30 is improved. Note that the metal nitride film 30 preferably contains at least elements of Group 13 and Group 15 elements.

[0065] Using FIG. 3, the preferable range of the atomic ratio of the metals constituting the oxide target containing zinc will be described. FIG. 3 is a diagram showing the atomic ratios of indium, gallium, and zinc included in the oxide target. Note that the atomic ratio of oxygen is not described in FIG. 3. Also, the terms of the atomic ratios of indium, gallium, and zinc included in the oxide target are denoted as [In], [Ga], and [Zn], respectively.

[0066] In FIG. 3, the broken lines represent the lines with the atomic ratios of [In]:[Ga]:[Zn] = (1 + α):(1 - α):1 (α is a real number of -1 or more and 1 or less), [In]:[Ga]:[Zn] = (1 + α):(1 - α):2, [In]:[Ga]:[Zn] = (1 + α):(1 - α):3, and [In]:[Ga]:[Zn] = (1 + α):(1 - α):4.

[0067] Also, the dashed-dotted lines represent the lines with the atomic ratios of [In]:[Ga]:[Zn] = 4:1:β (β is a real number of 0 or more), [In]:[Ga]:[Zn] = 2:1:β, [In]:[Ga]:[Zn] = 1:1:β, [In]:[Ga]:[Zn] = 1:2:β, and [In]:[Ga]:[Zn] = 1:4:β.

[0068] Region A shown in FIG. 3 shows an example of a preferable range of the atomic number ratios of indium, gallium, and zinc in the above oxide target. Region A includes In-Ga-Zn oxide targets with [In]:[Ga]:[Zn]=4:2:4.1 and [In]:[Ga]:[Zn]=1:1:1, an In-Zn oxide target with [In]:[Ga]:[Zn]=2:0:1 ([In]:[Zn]=2:1), and a zinc oxide target with [In]:[Ga]:[Zn]=0:0:1.

[0069] Note that the sputtering target used in the above sputtering method is not limited to an oxide target, and a oxynitride target may also be used. As the oxynitride target, for example, an indium gallium zinc oxynitride (In-Ga-Zn oxynitride) target, an indium gallium oxynitride (In-Ga oxynitride) target, etc. can be used.

[0070] The substrate temperature during the formation of the above metal oxynitride film is preferably room temperature (25°C) or higher and 500°C or lower, more preferably 80°C or higher and 400°C or lower, and even more preferably 150°C or higher and 350°C or lower. Since the film can be formed with the substrate temperature at 500°C or lower, the productivity of semiconductor devices etc. using the metal oxynitride film can be increased.

[0071] As the gas introduced into the reaction chamber during the formation of the metal oxynitride film, a gas containing nitrogen gas is preferably used. For example, as the gas, nitrogen gas, a mixed gas of nitrogen gas and oxygen gas, a mixed gas of nitrogen gas and a noble gas (argon, helium, etc.) etc. are preferably used. Here, the flow rate of nitrogen gas is preferably 50% or more and 100% or less in the total flow rate of the gas, more preferably 70% or more and 100% or less, and even more preferably 85% or more and 100% or less. Note that the composition of the obtained metal oxynitride film can be adjusted by adjusting the flow rate ratio of nitrogen gas to the flow rate of the gas.

[0072] <Sputtering apparatus> Next, with reference to FIG. 4, a sputtering apparatus according to a method for manufacturing a metal oxynitride film, which is one aspect of the present invention, will be described. FIG. 4 is a cross-sectional view for explaining a film formation chamber 201 included in the sputtering apparatus 200.

[0073] The film formation chamber 201 shown in FIG. 4 includes a substrate holder 202, a sputtering target 204, a backing plate 205, and a magnet unit 206. The magnet unit 206 can be provided with one or more (for example, magnet unit 206a and magnet unit 206b). Further, the magnet unit 206 can be fixed or can have a swing mechanism. The sputtering target 204 is disposed and fixed on the backing plate 205. The magnet unit 206 is disposed under the sputtering target 204 via the backing plate 205. When the substrate 203 is carried into the film formation chamber 201, the substrate 203 is disposed in contact with the substrate holder 202. The film formation chamber 201 has an air inlet 210a and an exhaust port 210b for supplying a gas (also referred to as a film formation gas). A film formation gas is supplied to the film formation chamber 201 through the air inlet 210a, and the film formation gas is exhausted through the exhaust port 210b.

[0074] FIG. 4 shows an example in which the magnet units 206a and 206b are provided. The magnet units 206a and 206b have a swing mechanism. The magnet unit 206a has a swing range 207a, and the magnet unit 206b has a swing range 207b. By swinging the magnet units 206a and 206b within the range where the sputtering target 204 is disposed, a uniform film can be formed. For example, the magnet unit 206a or the magnet unit 206b may be swung at a beat (which may be expressed in other words such as rhythm, pulse, frequency, cycle, etc.) of 0.1 Hz or more and 1 kHz or less.

[0075] The magnetic field received by the sputtering target 204 is determined by the voltage V2 applied to the substrate holder 202 and the voltage V1 applied to the backing plate 205. Also, the magnetic field received by the sputtering target 204 changes with the oscillation of the magnet unit 206. Since the region with a strong magnetic field becomes a high-density plasma region, the sputtering phenomenon of the sputtering target 204 is likely to occur in the vicinity thereof. When the sputtering target 204 contains multiple elements, the magnetic field intensity applied from the magnet unit 206a to the sputtering target 204 can be made different from the magnetic field intensity applied from the magnet unit 206b to the sputtering target 204. Elements corresponding to the magnetic field intensity are deposited on the substrate 203.

[0076] In addition, in FIG. 4, an example using a parallel plate type sputtering apparatus has been shown, but the method for forming a metal oxynitride film according to the present embodiment is not limited thereto. For example, a metal oxynitride film may be formed using a facing target type sputtering apparatus.

[0077] Since the sputtering method enables film formation at a low temperature, the productivity of semiconductor devices and the like using the metal oxynitride film can be increased.

[0078] According to one aspect of the present invention, a method for epitaxially growing and forming a metal oxynitride film at a low temperature can be provided. Also, according to one aspect of the present invention, a method for epitaxially growing and forming a metal oxynitride film without performing a high-temperature treatment before and after film formation of the metal oxynitride film can be provided. Also, one aspect of the present invention can provide a method for epitaxially growing and forming a metal nitride film on a metal oxynitride film without performing a high-temperature treatment. Also, according to one aspect of the present invention, a semiconductor device or the like using a metal nitride film epitaxially grown and formed on a metal oxynitride film can be provided. Also, according to one aspect of the present invention, the productivity of semiconductor devices or the like using a metal nitride film can be increased.

[0079] <Method for evaluating crystallinity and orientation of thin film> The evaluation of epitaxial growth can be carried out during or after the formation of the thin film, depending on the evaluation method.

[0080] Examples of evaluation methods for epitaxial growth during the formation of a thin film include, for example, Reflection High Energy Electron Diffraction (RHEED) and Surface Photoabsorption (SPA).

[0081] In addition, the epitaxial growth (crystallinity and orientation) of the formed thin film can be evaluated by combining measurements such as Transmission Electron Microscope (TEM), Reciprocal Space Mapping, pole figure measurement (φ scan), Out-of-Plane measurement, and In-Plane measurement in X-ray Diffraction (XRD).

[0082] Hereinafter, the measurement methods that can be used to evaluate the crystallinity and orientation of a thin film will be described.

[0083] <Reciprocal Space Mapping> Reciprocal Space Mapping will be described.

[0084] The reciprocal space is a space constituted by the basic vectors of the reciprocal space (also referred to as reciprocal lattice vectors), and the periodicity of the real space is reflected. Here, the reciprocal lattice vector b j is in the relationship of the following mathematical formula (1) with the basic vector a of the real space lattice. That is, the plane defined in the crystal of the real space is treated as a lattice point in the reciprocal lattice. i Specifically, the reciprocal lattice vector b is related to the real space lattice vector a by the following formula (1). That is, the plane defined in the real space crystal is regarded as a lattice point in the reciprocal lattice.

[0085]

Equation

[0086] The epitaxially grown thin film has a small variation in the crystal orientation of the crystals constituting the thin film, that is, a high degree of orientation. Therefore, when obtaining an inverse lattice space map for the epitaxially grown thin film, the intensity of the observed spot is high, and the full width at half maximum (FWHM) of the spot is small. On the other hand, when obtaining an inverse lattice space map for a thin film with a large variation in the crystal orientation of the crystals, that is, a low degree of orientation, the intensity of the observed spot is low, and the full width at half maximum of the spot is large. From the above, by obtaining an inverse lattice space map, the crystallinity and orientation of the thin film can be evaluated.

[0087] Using FIG. 5, an apparatus that can be used for X-ray analysis will be described. Here, as shown in FIG. 5, when viewing the X-ray analyzer from above, the direction in which the X-ray source source, the sample sample, and the detector detector are arranged in a row is defined as the ψ axis. Also, when viewing the X-ray analyzer from above, the direction perpendicular to the ψ axis is defined as the θ axis. Further, the direction perpendicular to the ψ axis and the θ axis is defined as the φ axis. That is, the φ axis is parallel to the direction when viewing the X-ray analyzer from above. Note that the axis defined as the ψ axis in this specification may be defined as the χ axis depending on the apparatus. Therefore, the ψ axis can also be referred to as the χ axis. Similarly, the axis defined as the θ axis in this specification may be defined as the ω axis depending on the apparatus. Therefore, the θ axis can also be referred to as the ω axis.

[0088] Note that a two-dimensional detector may be used as the detector. The two-dimensional detector has position information in the 2θ and χ directions on the detection surface. Note that the detector detector shown in FIG. 5 is shown by imitating a two-dimensional detector. Note that unless otherwise specified, in this specification, a value using CuKα rays (wavelength: 0.15418 nm) as the X-ray source is used.

[0089] <Pole figure measurement> Pole figure measurement is a method of measuring the distribution of diffraction intensity by rotating the sample in all directions while keeping the positions (angles) of the X-ray source and the detector constant.

[0090] In addition, an analysis that scans in the φ direction with respect to a predetermined crystal plane of a sample is called a φ scan, and a φ scan with a small full width at half maximum (sometimes referred to as Δφ) is considered to have good in-plane orientation. In addition, this in-plane orientation may sometimes be referred to as crystallinity in the specification.

[0091] The diffraction intensity obtained by pole figure measurement will be described with reference to FIG. 6. The diffraction intensity obtained by pole figure measurement is represented by a pole figure. FIG. 6A shows the pole figure. As shown in FIG. 6A, the center P0 of the pole figure has an angle ψ of 0°, and the outer periphery P1 of the pole figure has an angle ψ of 90°. Also, a straight line extending vertically upward from the center P0 of the pole figure toward the outer periphery P1 of the pole figure (the straight line indicated by the dashed line P0-P2 in FIG. 6A) has an angle φ of 0°, and the angle formed by this straight line and a straight line extending from the center P0 of the pole figure toward the outer periphery P1 of the pole figure (the straight line indicated by the dashed line P0-P3 in FIG. 6A) is the angle φ. In FIG. 6A, it is illustrated such that the angle φ increases when rotated counterclockwise, but it is not limited to this. Depending on the apparatus, etc., the angle φ may increase when rotated clockwise. Also, depending on the range of the ψ scan, the angle of the pole figure obtained by pole figure measurement may not be acquired in the range of 0° or more and 90° or less. In pole figure measurement, the axis referred to as ψ in this specification may be referred to as α depending on the apparatus. Therefore, ψ can also be referred to as α. Similarly, the axis referred to as φ in this specification may be referred to as β depending on the apparatus. Therefore, θ can also be referred to as β.

[0092] FIGS. 6B and 6C show schematic diagrams of the diffraction intensity obtained by pole figure measurement. FIG. 6B is a schematic diagram of the diffraction intensity when a spot-like intensity distribution is observed on a concentric circle of the angle ψ (the circle indicated by the dashed line in the figure), and FIG. 6C is a schematic diagram of the diffraction intensity when a ring-like intensity distribution is observed.

[0093] For example, the (101) plane of the wurtzite-type structure has six-fold symmetry. That is, when performing pole figure measurement on a c-axis epitaxial thin film having a wurtzite-type structure crystal, as shown in Fig. 6B, six spot-like intensity distributions (diffraction peaks) are observed on a concentric circle at a certain angle ψ. Therefore, when a thin film having a wurtzite-type structure crystal grows epitaxially on the c-axis, a diffraction peak showing six-fold symmetry is observed in the pole figure measurement or φ scan of the (101) plane of the crystal of the thin film. Specifically, diffraction peaks are observed at about 60° intervals on a concentric circle where the angle ψ is about 62°.

[0094] On the other hand, when performing pole figure measurement on a non-epitaxially grown thin film, a ring-like intensity distribution as shown in Fig. 6C is observed, or no diffraction peak is observed. Therefore, by analyzing the intensity distribution observed in the pole figure measurement, it is possible to evaluate whether the thin film is epitaxially grown.

[0095] In addition, in the pole figure measurement or φ scan of the (220) plane of a single crystal YSZ substrate, a diffraction peak showing three-fold symmetry is observed. Specifically, diffraction peaks are observed at about 120° intervals on a concentric circle where the angle ψ is about 35°. Also, in the pole figure measurement or φ scan of the (300) plane of a single crystal a-plane sapphire substrate, a diffraction peak showing two-fold symmetry is observed. Specifically, diffraction peaks are observed at about 180° intervals on a concentric circle where the angle ψ is about 30°.

[0096] <Out-of-plane measurement and In-plane measurement> Measurements using the XRD method include Out-of-plane measurement and In-plane measurement. Out-of-plane measurement is a method for evaluating crystal planes parallel to the surface of the thin film, and In-plane measurement is a method for evaluating crystal planes perpendicular to the surface of the thin film. In Out-of-plane measurement and In-plane measurement, a zero-dimensional detector may be used as the detector.

[0097] As described above, the configurations, methods, etc. shown in the present embodiment can be used in appropriate combination with those shown in other embodiments and examples.

[0098] (Embodiment 2) In the present embodiment, the use of the epitaxially grown metal oxynitride film shown in the previous embodiment will be described.

[0099] Examples of the uses of the metal oxynitride film include inorganic light-emitting elements, light-receiving elements, power semiconductor elements, semiconductor devices, etc. In particular, it is preferably used for inorganic light-emitting elements. Note that the inorganic light-emitting elements include LEDs (Light Emitting Diodes) and micro LEDs.

[0100] Using FIG. 7, a configuration example of an inorganic light-emitting element using the metal oxynitride film will be described. In the present embodiment, an inorganic light-emitting element having a double heterojunction will be described. However, one aspect of the present invention is not limited to this, and an inorganic light-emitting element having a quantum well junction may also be used.

[0101] FIG. 7 shows an inorganic light-emitting element 100 using a metal nitride film formed on a metal oxynitride film according to one aspect of the present invention. As shown in FIG. 7, the inorganic light-emitting element 100 includes a substrate 10, a buffer layer formed of a metal oxynitride film 20, an n-type clad layer 31, an active layer 32, a p-type clad layer 33, an electrode 35, and an electrode 36. The n-type clad layer 31, the active layer 32, and the p-type clad layer 33 can be formed of a metal nitride film. Note that a conductor 34 may be provided between the p-type clad layer 33 and the electrode 36. The metal oxynitride film 20 has conductivity and functions as an electrode of the inorganic light-emitting element 100. As an example, in the inorganic light-emitting element 100, the metal oxynitride film 20 is used as a cathode electrode, and the conductor 34 is used as an anode electrode.

[0102] Note that the n-type clad layer 31, which is a metal nitride film, can achieve ohmic contact with the electrode 35 through the metal oxynitride film 20. Also, the p-type clad layer 33, which is a metal nitride film, can achieve ohmic contact with the electrode 36 through the conductor 34.

[0103] The active layer 32 is sandwiched between the n-type clad layer 31 and the p-type clad layer 33. In the active layer 32, electrons and holes combine to emit light. That is, the active layer 32 can be called a light-emitting layer. For example, the n-type clad layer 31 preferably contains silicon, germanium, or tin as an n-type dopant. Also, the p-type clad layer 33 preferably contains magnesium as a p-type dopant. The active layer 32 preferably contains indium, zinc, or silicon.

[0104] By appropriately selecting the atomic ratio of the metal constituting the metal oxynitride film 20 according to one aspect of the present invention, the dopant added to the metal nitride film, the flow rate of nitrogen gas introduced into the reaction chamber during film formation, etc., the conductivity (or insulating property), bandgap, light transmittance, etc. of the metal oxynitride film 20 and the metal nitride film can be adjusted. For example, the higher the flow rate of the nitrogen gas, the higher the crystallinity and conductivity of the film tend to be.

[0105] Furthermore, the metal oxynitride film 20 can function as a buffer layer for epitaxially growing a thin film of metal nitride on the film. Therefore, the crystallinity of the n-type clad layer 31, active layer 32, and p-type clad layer 33 formed on the metal oxynitride film 20 can be enhanced. Note that the crystal structure of the metal nitride film is the same hexagonal system as that of the metal oxynitride film 20, and in particular, it is a wurtzite-type crystal structure. Therefore, for the n-type clad layer 31 or active layer 32 formed on the metal oxynitride film 20, it is preferable to use a material that forms a wurtzite-type crystal structure such as gallium nitride or an indium-gallium nitride compound.

[0106] As described above, the metal oxynitride film 20 has a function as a buffer layer for hexagonal crystal growth and also has a function as an electrode. By using the metal oxynitride film 20 as the buffer layer, it becomes easier to epitaxially grow the n-type clad layer 31 or the active layer 32, and the crystallinity of the n-type clad layer 31 or the active layer 32 is increased. Therefore, the characteristics of the inorganic light-emitting element such as luminous efficiency and durability can be improved.

[0107] FIG. 8 is a diagram showing a configuration example of a semiconductor device. The semiconductor device has an inorganic light-emitting element, a transistor, and a capacitor. Therefore, in one aspect of the present invention, a configuration example in which the semiconductor device is applied to a pixel of a display device will be described. Note that the display device described with reference to FIG. 8 can be applied to an illumination device. By using the inorganic light-emitting element which is one aspect of the present invention, a display device with good luminous efficiency and high reliability can be manufactured.

[0108] The pixel has an inorganic light-emitting element 100, a transistor 92, and a capacitor 95. The inorganic light-emitting element 100 is formed on the substrate 10 via the metal oxynitride film 20. The inorganic light-emitting element 100 is configured by sequentially forming an n-type clad layer 31, an active layer 32, a p-type clad layer 33, and a conductor 34 on the metal oxynitride film 20.

[0109] A capacitor 95 is formed on the conductor 34, and a transistor 92 is formed on the capacitor 95. A substrate 11 is provided on the back surface side of the surface of the substrate 10 where the inorganic light-emitting element 100 is formed via a functional layer 12. Note that the functional layer 12 preferably has one or both of a coloring layer and a color conversion layer that are different for each pixel. Note that the functional layer 12 is preferably disposed at a position overlapping the pixel. The functional layer 12 has functional layers 12a to 12c, and the regions of the functional layers 12a to 12c that overlap the pixel are determined by a light-shielding layer 13.

[0110] In FIG. 8, an example in which a pixel has one transistor is shown for simplicity of explaining the figure, but the number of transistors is not limited to one. A plurality of transistors can be arranged at positions overlapping with the capacitor. Note that the transistors can also be arranged at positions overlapping with the inorganic light-emitting element and the capacitor. For example, a pixel may have a configuration including a plurality of transistors.

[0111] The insulator 41 is formed so as to cover the inorganic light-emitting element 100. Therefore, the insulator 41 preferably contacts the conductor 34 and the metal oxynitride film 20. The conductor 52 is formed on the insulator 41. The conductor 52 functions as one of the electrodes of the capacitor 95. Note that the conductor 52 is electrically connected to the conductor 34 through the opening of the insulator 41 formed on the inorganic light-emitting element 100. Further, the conductor 52 functions as a reflective film that reflects the light emitted from the inorganic light-emitting element 100.

[0112] The insulator 43 is formed on the conductor 52. The insulator 43 preferably contacts the insulator 41 and the metal oxynitride film 20. The conductor 54 is formed on the insulator 43. Note that the conductor 54 functions as the other electrode of the capacitor 95. Therefore, the capacitor 95 is formed in a region where the conductor 54 overlaps the conductor 52 with the insulator 43 interposed therebetween.

[0113] The insulator 47 is formed on the conductor 54. Note that the insulator 47 preferably contacts the insulator 43. Further, the insulator 47 is preferably a colored layer. The colored layer preferably reduces the transmission of the light emitted from the inorganic light-emitting element 100.

[0114] For the conductors 52 and 54, a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, silver, copper, chromium, neodymium, and scandium, or a metal nitride film (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film) composed of the above-described elements can be used. Alternatively, 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 can also be applied. Note that for the conductor 52, it is preferable to use a metal film with high reflectivity (such as aluminum, an alloy containing aluminum, or silver).

[0115] As an example, the inorganic light-emitting element 100 emits lights L1 to L5. When the substrate 11 serves as the display surface of the display device, the light L1 emitted by the inorganic light-emitting element 100 can contribute to the display. The lights L2 to L5 are lights emitted in the direction of the capacitor 95. The light L2 is emitted from the display surface with one of the electrodes of the capacitor 95 serving as a reflective film. However, the light L3 reflected by the reflective film is reduced in the light emitted to the display surface by the light-shielding layer 13. By having the light-shielding layer 13, it is possible to prevent the light L3 reflected by the reflective film from being emitted through the functional layer 12b of the adjacent pixel. Also, the lights L4 and L5 reflected by the reflective film can prevent the light emitted to the adjacent pixel from being mixed in. Therefore, the insulator 47 can maintain the purity and luminance of the light emitted by the pixel and reduce the influence of the light emitted by other pixels.

[0116] Note that the upper surface of the insulator 47 is preferably planarized by a planarization process using a chemical mechanical polishing (CMP) method or the like to enhance flatness. A transistor 92 is formed above the insulator 47.

[0117] An insulator 49 and an insulator 61 are sequentially stacked on an insulator 47. Further, a transistor 92 is provided above the insulator 49. An insulator 81 is provided above the transistor 92. A BEOL (Back end of line) region for forming wiring of the semiconductor device is provided above the transistor 92. For example, it has a conductor 59 (conductor 59a to conductor 59d) that connects the transistor 92 and a capacitor. Also, the terminal 58 can be connected to the conductor 59. Note that an insulator 83 is provided above the insulator 81. A conductor 58 that functions as wiring is provided above the insulator 83. An insulator 85 is provided above the conductor 58, and a conductor 59 that functions as wiring is provided above the insulator 85. An insulator 87 is provided above the conductor 59, and conductors 72 (conductor 72a, conductor 72b) that function as terminals are provided above the insulator 87. Note that a part of the transistor 92 may be arranged to be embedded in a part of the insulator 49 and the insulator 61.

[0118] In this embodiment, the conductor 58 and the conductor 59 are shown in a single-layer configuration, but the present invention is not limited to this configuration, and a laminated configuration of two or more layers may be used. For example, a conductor having barrier properties, and a conductor having high adhesiveness to a conductor having high conductivity may be formed between a conductor having barrier properties and a conductor having high conductivity.

[0119] Note that the conductor 58 and the conductor 59 can use a conductive material such as a metal material, an alloy material, or a metal oxide material. It is preferable to use a high melting point material such as tungsten or molybdenum that achieves both heat resistance and conductivity, and it is particularly preferable to use tungsten. Also, when forming in the same process as other components such as conductors, Cu (copper), Al (aluminum), or the like, which are low-resistance metal materials, may be used.

[0120] In addition, in the insulator 47, insulator 49, insulator 61, insulator 81, insulator 83, insulator 85, or insulator 87, conductors such as the conductor 56 (conductor 56a to conductor 56d), conductor 71 (conductor 71a, conductor 71b), or the conductor (for example, conductor 503) constituting the transistor 92 are arranged to be embedded. Note that the conductor 56 has a function as a plug connected to the capacitor 95 and the transistor 92, or as a wiring. Also, the conductor 71 has a function as a plug connected to the metal oxynitride film 20 that functions as the cathode electrode of the inorganic light-emitting element 100, or as a wiring. Note that the metal oxynitride film 20 functions as a common electrode. Therefore, it is preferable to provide one or more conductors 71 in the display device having a plurality of pixels. As an example, FIG. 8 shows an example in which the conductor 71a and the conductor 71b are provided for one pixel, but the present invention is not limited thereto.

[0121] As materials for the conductor 56 and the conductor 71, conductive materials such as metal materials, alloy materials, metal nitride materials, or metal oxide materials can be used alone or in a stacked manner. It is preferable to use high melting point materials such as tungsten and molybdenum that achieve both heat resistance and conductivity, and it is more preferable to use tungsten. Alternatively, it is preferable to form the conductor with a low resistance conductive material such as aluminum or copper. By using a low resistance conductive material, the wiring resistance can be reduced.

[0122] Note that the insulator 63, insulator 65, insulator 67, and insulator 69 will be described in detail with reference to FIG. 9.

[0123] Next, transistor 92 will be described. The semiconductor layer of transistor 92 preferably contains oxygen and further contains any one or more of In, Ga, Sn, or Zn. Therefore, the semiconductor layer of transistor 92 can be said to have an oxide semiconductor. Note that a transistor in which the semiconductor layer where the channel of the transistor is formed contains an oxide semiconductor (Oxide Semiconductor: OS), which is a type of metal oxide, is called an "OS transistor" or "OS-FET". Note that it is known that the electrical characteristics of an OS transistor vary little with temperature changes. In addition, since the energy gap of the semiconductor layer of an OS transistor is large, it can exhibit an extremely low off-current characteristic of several yA / μm (current value per 1-μm channel width). Therefore, an OS transistor is preferably applied to a memory device. The structure of the OS transistor will be described in detail with reference to FIG. 9.

[0124] Here, a pixel using an OS transistor will be described. A pixel using an OS transistor can suppress deterioration of data held in the pixel even when power supply is stopped. Therefore, since the pixel can reduce the capacity for holding data, a display device suitable for high density can be provided. In addition, the pixel can reduce the number of times of image rewriting in a still image by utilizing an extremely low off-current characteristic, enabling intermittent driving (IDS driving) that leads to low power consumption.

[0125] Note that IDS drive is an idling stop drive that operates at a frame frequency lower than normal. In IDS drive, after executing the writing process of image data, the rewriting of the image data is stopped. By once writing the image data and then extending the interval until the writing of the next image data, it is possible to reduce the power consumption required for the writing of the image data during that period. The frame frequency of IDS drive can be, for example, 1 / 100 or more and 1 / 10 or less of the normal operation (typically 60 Hz or more and 240 Hz or less). For a still image, the video signal is the same between consecutive frames. Therefore, the IDS drive mode is particularly effective when displaying a still image.

[0126] Also, the off-current of the OS transistor hardly increases even in a high-temperature environment. Specifically, the off-current hardly increases even in an environmental temperature of room temperature or higher and 200°C or lower. Also, the on-current hardly decreases even in a high-temperature environment. Also, the OS transistor has a high breakdown voltage between the source and the drain. Even when the inorganic light-emitting element becomes high temperature, by using the OS transistor for the transistors constituting a display device, a lighting device, etc., an operation-stable and highly reliable display device, a lighting device, etc. can be realized even in a high-temperature environment.

[0127] Also, the OS transistor can be formed by using a sputtering method during the BEOL process for forming the wiring of the semiconductor device. Therefore, one semiconductor device can be formed by using transistors with different transistor characteristics. In other words, by using the OS transistor, a system on chip (SOC) can be easily formed.

[0128] Note that the OS transistor can have a back gate. The back gate is arranged so as to sandwich the channel formation region of the semiconductor layer between the gate and the back gate. The back gate can function in the same manner as the gate. Also, by changing the voltage of the back gate, the threshold voltage of the transistor can be changed. The voltage of the back gate may be the same voltage as the gate, or may be GND or an arbitrary voltage.

[0129] Also, generally, since the gate and the back gate are formed of a conductive layer, they have a function (particularly an electrostatic shielding function against static electricity) of preventing an electric field generated outside the transistor from acting on the semiconductor layer where the channel is formed. That is, it is possible to prevent fluctuations in the electrical characteristics of the transistor due to the influence of an external electric field such as static electricity.

[0130] Next, the insulators 41, 43, 47, 49, 61, 85, and 87 will be described. It is preferable to use a material having a barrier property against oxygen and hydrogen for any of the above-described insulators.

[0131] In particular, for the insulators 49 and 61, it is preferable to use a film having a barrier property such that hydrogen and impurities do not diffuse from the region where the inorganic light-emitting element 100 is provided to the region where the transistor 92 is provided. Also, for the insulator 83, it is preferable to use a film having a barrier property such that hydrogen and impurities do not diffuse from the outside to the region where the transistor 92 is provided.

[0132] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 92, 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 92 and the inorganic light-emitting element. Specifically, the film that suppresses the diffusion of hydrogen is a film having a small amount of hydrogen desorption.

[0133] The amount of hydrogen desorption can be analyzed using, for example, temperature-programmed desorption gas analysis (TDS). For example, the amount of hydrogen desorption of the insulator 49 is, in TDS analysis, in the range where the surface temperature of the film is from 50°C to 500°C, and the desorption amount converted to hydrogen atoms, when converted per unit area of the insulator 49, is 10×10 15 atoms / cm 2 Hereinafter, preferably 5×10 15 atoms / cm 2The following may be sufficient.

[0134] As an example of a 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 92, 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 92 and the inorganic light-emitting element 100. Specifically, the film that suppresses the diffusion of hydrogen is a film with a small amount of hydrogen desorption.

[0135] In particular, silicon nitride has a high blocking effect of not allowing the film to permeate both oxygen and impurities such as hydrogen and moisture that are factors causing fluctuations in the electrical characteristics of the transistor. Therefore, silicon nitride can prevent the incorporation of impurities such as hydrogen and moisture into the transistor 92 during and after the manufacturing process of the transistor. In addition, it is possible to suppress the release of oxygen from the oxide constituting the transistor 92. Therefore, it is suitable to be used as a protective film for the transistor 92.

[0136] Further, for example, it is preferable that the insulator 61 has a lower dielectric constant than the insulator 49. For example, the relative dielectric constant of the insulator 61 is preferably less than 4, more preferably less than 3. Also, for example, the relative dielectric constant of the insulator 61 is preferably 0.7 times or less, more preferably 0.6 times or less, of the relative dielectric constant of the insulator 49. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between the wirings can be reduced. For example, as the insulator 61, a silicon oxide film, a silicon oxynitride film, or the like can be used.

[0137] Further, the conductors 56 and 71 in the region in contact with the insulator 49 are preferably conductors having a barrier property against oxygen, hydrogen, and water. With this configuration, the inorganic light-emitting element 100 can be separated from the transistor 92 by a layer having a barrier property against oxygen, hydrogen, and water, and the diffusion of hydrogen from the inorganic light-emitting element 100 to the transistor 92 can be suppressed.

[0138] Next, the substrate will be described. Since the substrate 10 is located on the side where light from the light-emitting diode is extracted, it is preferable to use a material with high transparency to visible light. Examples of materials that can be used for the substrate 10 and the substrate 11 include sapphire, yttria-stabilized zirconia, glass, quartz, resin, and the like. Note that a film such as a resin film may be used for the substrate 10 and the substrate 11. This enables the display device to be lighter and thinner.

[0139] As the color conversion layer, it is preferable to use a phosphor or quantum dots (QD: Quantum Dot). In particular, quantum dots have a narrow peak width of the emission spectrum and can obtain light emission with good color purity. Thereby, the display quality of the display device can be improved.

[0140] The color conversion layer can be formed using a droplet discharge method (e.g., inkjet method), coating method, imprint method, various printing methods (screen printing, offset printing), etc. Also, a color conversion film such as a quantum dot film may be used.

[0141] When processing the film to be the color conversion layer, it is preferable to use a photolithography method. As the photolithography method, there are a method of forming a resist mask on the thin film to be processed, processing the thin film by etching or the like, and removing the resist mask, and a method of forming a photosensitive thin film and then performing exposure and development to process the thin film into a desired shape. For example, an island-shaped color conversion layer can be formed by forming a thin film using a material in which quantum dots are mixed in a photoresist and processing the thin film using a photolithography method.

[0142] The materials constituting the quantum dots are not particularly limited, and examples thereof include group 14 elements, group 15 elements, group 16 elements, compounds composed of a plurality of group 14 elements, compounds of elements belonging to groups 4 to 14 and group 16 elements, compounds of group 2 elements and group 16 elements, compounds of group 13 elements and group 15 elements, compounds of group 13 elements and group 17 elements, compounds of group 14 elements and group 15 elements, compounds of group 11 elements and group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, various semiconductor clusters, and the like.

[0143] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, a compound of selenium, zinc, and cadmium, a compound of indium, arsenic, and phosphorus, a compound of cadmium, selenium, and sulfur, a compound of cadmium, selenium, and tellurium, a compound of indium, gallium, and arsenic, a compound of indium, gallium, and selenium, a compound of indium, selenium, and sulfur, a compound of copper, indium, and sulfur, and combinations thereof, etc. may be mentioned. Further, so-called alloy-type quantum dots in which the composition is represented by an arbitrary ratio may also be used.

[0144] Examples of the structure of quantum dots include core type, core-shell type, core-multi-shell type, etc. Further, since the proportion of surface atoms in quantum dots is high, they have high reactivity and tend to aggregate. Therefore, it is preferable that a protective agent is attached to or a protecting group is provided on the surface of the quantum dots. By attaching the protective agent or providing the protecting group, aggregation can be prevented and the solubility in a solvent can be increased. It is also possible to reduce the reactivity and improve the electrical stability.

[0145] Since the bandgap of quantum dots increases as their size decreases, the size of the quantum dots is appropriately adjusted so as to obtain light of a desired wavelength. As the size of the crystal decreases, the emission of the quantum dots shifts toward the blue side, that is, toward the high-energy side. Therefore, by changing the size of the quantum dots, the emission wavelength can be adjusted over the wavelength regions of the spectra in the ultraviolet region, visible region, and infrared region. The size (diameter) of the quantum dots is, for example, 0.5 nm or more and 20 nm or less, preferably 1 nm or more and 10 nm or less. The narrower the size distribution of the quantum dots, the narrower the emission spectrum and the better the color purity of the emission can be obtained. Further, the shape of the quantum dots is not particularly limited, and may be spherical, rod-shaped, disk-shaped, or other shapes. A quantum rod, which is a rod-shaped quantum dot, has a function of exhibiting light with directivity.

[0146] The colored layer is a colored layer that transmits light in a specific wavelength range. For example, a color filter that transmits light in the wavelength range of red, green, blue, or yellow can be used. Examples of materials that can be used for the colored layer include metal materials, resin materials, and resin materials containing pigments or dyes.

[0147] As shown in FIGS. 9A and 9B, the transistor 92 includes a conductor 503 disposed to be embedded in the insulator 49 and the insulator 61, an insulator 63 disposed on the insulator 61 and the conductor 503, an insulator 65 disposed on the insulator 63, an insulator 67 disposed on the insulator 65, an oxide 530a disposed on the insulator 67, an oxide 530b disposed on the oxide 530a, conductors 542a and 542b disposed apart from each other on the oxide 530b, an insulator 81 disposed on the conductors 542a and 542b and having an opening formed by overlapping between the conductor 542a and the conductor 542b, an insulator 545 disposed on the bottom surface and the side surface of the opening, and a conductor 560 disposed on the formation surface of the insulator 545.

[0148] Also, as shown in FIGS. 9A and 9B, it is preferable that an insulator 69 is disposed between the oxide 530a, the oxide 530b, the conductor 542a, and the conductor 542b and the insulator 81. Also, as shown in FIGS. 9A and 9B, the conductor 560 preferably includes a conductor 560a provided inside the insulator 545 and a conductor 560b provided to be embedded inside the conductor 560a. Also, as shown in FIGS. 9A and 9B, it is preferable that an insulator 83 is disposed on the insulator 81, the conductor 560, and the insulator 545.

[0149] In this specification and the like, the oxide 530a and the oxide 530b may be collectively referred to as the oxide 530.

[0150] Note that in the transistor 92, a configuration in which two layers of the oxide 530a and the oxide 530b are laminated in a region where a channel is formed and in its vicinity is shown, but the present invention is not limited to this. For example, a configuration may be provided in which a single layer of the oxide 530b or a laminated configuration of three or more layers is provided.

[0151] In addition, in the transistor 92, the conductor 560 is shown in a two-layer stacked structure, but the present invention is not limited to this. For example, the conductor 560 may have a single-layer structure or a stacked structure of three or more layers. Also, the transistor 92 shown in FIGS. 8 and 12 is an example, and the present invention is not limited to its configuration. An appropriate transistor may be used according to the circuit configuration, driving method, etc.

[0152] Here, the conductor 560 functions as the gate electrode of the transistor, and the conductors 542a and 542b function as the source electrode and the drain electrode, respectively. As described above, the conductor 560 is formed so as to be embedded in the opening of the insulator 81 and the region sandwiched between the conductors 542a and 542b. The arrangement of the conductor 560, the conductor 542a, and the conductor 542b is self-aligned with respect to the opening of the insulator 81. That is, in the transistor 92, the gate electrode can be self-alignedly arranged between the source electrode and the drain electrode. Therefore, the conductor 560 can be formed without providing an alignment margin, and the occupied area of the transistor 92 can be reduced. Thereby, miniaturization and high integration of the semiconductor device can be achieved.

[0153] Furthermore, since the conductor 560 is self-alignedly formed in the region between the conductors 542a and 542b, the conductor 560 does not have a region overlapping with the conductor 542a or the conductor 542b. Thereby, the parasitic capacitance formed between the conductor 560, the conductor 542a, and the conductor 542b can be reduced. Therefore, the switching speed of the transistor 92 can be improved, and high frequency characteristics can be achieved.

[0154] Conductor 560 may function as a first gate (also referred to as a top gate) electrode. Also, conductor 503 may function as a second gate (also referred to as a bottom gate) electrode. In that case, the threshold voltage of transistor 92 can be controlled by changing the voltage applied to conductor 503 independently without linking it to the voltage applied to conductor 560. In particular, by applying a negative voltage to conductor 503, the threshold voltage of transistor 92 can be made greater than 0V, and the off-current can be reduced. Therefore, applying a negative voltage to conductor 503 can make the drain current smaller when the voltage applied to conductor 560 is 0V than when no negative voltage is applied.

[0155] Conductor 503 is arranged to overlap with oxide 530 and conductor 560. Thereby, when voltages are applied to conductor 560 and conductor 503, the electric field generated from conductor 560 and the electric field generated from conductor 503 are connected and can cover the channel formation region formed in oxide 530.

[0156] In this specification and the like, a configuration of a transistor in which a channel formation region is electrically surrounded by an electric field of a pair of gate electrodes (a first gate electrode and a second gate electrode) is referred to as a surrounded channel (S-channel) configuration. Further, in this specification and the like, the surrounded channel (S-channel) configuration has a feature that the side surfaces and the periphery of the oxide 530 in contact with the conductors 542a and 542b that function as a source electrode and a drain electrode are of the same type I as the channel formation region. Also, since the side surfaces and the periphery of the oxide 530 in contact with the conductors 542a and 542b are in contact with the insulator 69, they can be of type I similar to the channel formation region. Note that, in this specification and the like, type I can be treated in the same manner as high-purity intrinsic described later. Further, the S-channel configuration disclosed in this specification and the like is different from the Fin type configuration and the planar type configuration. By adopting the S-channel configuration, it is possible to enhance the resistance to the short-channel effect, in other words, to obtain a transistor in which the short-channel effect is less likely to occur.

[0157] Further, the conductor 503 has the same configuration as the conductor 56. The conductor 503a is formed in contact with the inner walls of the openings of the insulator 49 and the insulator 61, and the conductor 503b is further formed inside. Note that, in the transistor 92, a configuration in which the conductor 503a and the conductor 503b are stacked is shown, but the present invention is not limited thereto. For example, the conductor 503 may be provided in a single-layer or a stacked configuration of three or more layers. In FIG. 8, an example in which the conductor 56 is a single layer is shown, and in FIG. 9, an example in which the conductor 503 has two layers is shown.

[0158] Here, it is preferable to use a conductive material for the conductor 503a that has a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms (it is difficult for the above impurities to permeate). Or, it is preferable to use a conductive material that has a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.) (it is difficult for the above oxygen to permeate). Note that in this specification, the function of suppressing the diffusion of impurities or oxygen means the function of suppressing the diffusion of any one or all of the above impurities or the above oxygen.

[0159] For example, since the conductor 503a has a function of suppressing the diffusion of oxygen, it is possible to suppress the conductor 503b from being oxidized and the conductivity from decreasing.

[0160] Also, when the conductor 503 also serves as a wiring function, it is preferable to use a highly conductive material mainly composed of tungsten, copper, or aluminum for the conductor 503b. Note that in this embodiment, the conductor 503 is illustrated as a laminate of the conductor 503a and the conductor 503b, but the conductor 503 may have a single-layer structure.

[0161] The insulators 63, 65, and 67 have a function as a second gate insulating film.

[0162] Here, as the insulator 67 in contact with the oxide 530, it is preferable to use an insulator containing more oxygen than the stoichiometric composition. Such oxygen is likely to be released from the film by heating. In this specification and the like, the oxygen released by heating may be referred to as "excess oxygen". That is, it is preferable that a region containing excess oxygen (also referred to as an "excess oxygen region") is formed in the insulator 67. By providing such an insulator containing excess oxygen in contact with the oxide 530, the oxygen vacancies (also referred to as Vo: oxygen vacancy) in the oxide 530 can be reduced, and the reliability of the transistor 92 can be improved. When hydrogen enters the oxygen vacancies in the oxide 530, such defects (hereinafter sometimes referred to as VoH) may function as donors and generate electrons as carriers. Also, a part of the hydrogen may combine with oxygen bonded to metal atoms to generate electrons as carriers. Therefore, a transistor using an oxide semiconductor containing a large amount of hydrogen is likely to have normally-on characteristics. Also, since hydrogen in the oxide semiconductor is likely to move due to stress such as heat and an electric field, if the oxide semiconductor contains a large amount of hydrogen, the reliability of the transistor may deteriorate. In one aspect of the present invention, it is preferable to reduce VoH in the oxide 530 as much as possible to make it highly pure intrinsic or substantially highly pure intrinsic. Thus, in order to obtain an oxide semiconductor in which VoH is sufficiently reduced, it is important to remove impurities such as moisture and hydrogen in the oxide semiconductor (also referred to as "dehydration" or "dehydrogenation treatment"), and to supply oxygen to the oxide semiconductor to compensate for oxygen vacancies (also referred to as "oxygen addition treatment"). By using an oxide semiconductor in which impurities such as VoH are sufficiently reduced in the channel formation region of the transistor, stable electrical characteristics can be imparted.

[0163] As the insulator having an excess oxygen region, specifically, it is preferable to use an oxide material in which a part of the oxygen is desorbed by heating. An oxide that desorbs oxygen by heating means that, in TDS (Thermal Desorption Spectroscopy) analysis, the desorption amount of oxygen in terms of oxygen atoms is 1.0×10 18 atoms / cm 3Preferably, it is 1.0×10 19 atoms / cm 3 or more, more preferably 2.0×10 19 atoms / cm 3 or more, or 3.0×10 20 atoms / cm 3 or more. The oxide film is as described above. Note that the surface temperature of the film during the above TDS analysis is preferably in the range of 100°C or more and 700°C or less, or 100°C or more and 400°C or less.

[0164] In addition, the insulator having the above excess oxygen region and the oxide 530 may be brought into contact with each other and subjected to any one or more of heat treatment, microwave treatment, or RF treatment. By performing this treatment, water or hydrogen in the oxide 530 can be removed. For example, in the oxide 530, a reaction occurs in which the bond of VoH is broken, in other words, a reaction of "VoH→Vo+H" occurs, and dehydrogenation can be achieved. Part of the hydrogen generated at this time may combine with oxygen to form H2O and be removed from the oxide 530 or the insulator near the oxide 530. Also, part of the hydrogen may be gettered by the conductor 542.

[0165] In addition, the above microwave treatment is preferably performed using, for example, a device having a power source for generating high-density plasma or a device having a power source for applying RF to the substrate side. For example, by using a gas containing oxygen and high-density plasma, high-density oxygen radicals can be generated, and by applying RF to the substrate side, the oxygen radicals generated by the high-density plasma can be efficiently introduced into the oxide 530 or the insulator near the oxide 530. Also, the above microwave treatment may be performed at a pressure of 133 Pa or more, preferably 200 Pa or more, and more preferably 400 Pa or more. Also, as the gas introduced into the device for performing the microwave treatment, for example, oxygen and argon are used, and the oxygen flow ratio (O2 / (O2+Ar)) is 50% or less, preferably 10% or more and 30% or less.

[0166] Also, during the manufacturing process of the transistor 92, it is preferable to perform a heat treatment in a state where the surface of the oxide 530 is exposed. The heat treatment may be performed, for example, at 100°C or higher and 450°C or lower, more preferably at 350°C or higher and 400°C or lower. The heat treatment is performed in an atmosphere of nitrogen gas or an inert gas, or an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas. For example, the heat treatment is preferably performed in an oxygen atmosphere. Thereby, oxygen can be supplied to the oxide 530 to reduce oxygen vacancies (Vo). Also, the heat treatment may be performed under reduced pressure. Or, after performing the heat treatment in an atmosphere of nitrogen gas or an inert gas, in order to supplement the desorbed oxygen, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas. Or, after performing the heat treatment in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas, the heat treatment may be continuously performed in an atmosphere of nitrogen gas or an inert gas.

[0167] Note that by performing an oxygen addition treatment on the oxide 530, the oxygen vacancies in the oxide 530 can be repaired with the supplied oxygen, in other words, the reaction of "Vo + O → null" can be promoted. Further, by reacting the supplied oxygen with the hydrogen remaining in the oxide 530, the hydrogen can be removed (dehydrated) as H2O. Thereby, it is possible to suppress the recombination of the hydrogen remaining in the oxide 530 with oxygen vacancies to form VH. O H can be suppressed.

[0168] Also, when the insulator 67 has an excess oxygen region, it is preferable that the insulator 65 has a function of suppressing the diffusion of oxygen (for example, oxygen atoms, oxygen molecules, etc.) (the oxygen is difficult to permeate).

[0169] Since the insulator 65 has a function of suppressing the diffusion of oxygen and impurities, the oxygen possessed by the oxide 530 does not diffuse to the insulator 63 side, which is preferable. Also, the conductor 503 can be suppressed from reacting with the oxygen possessed by the insulator 67 and the oxide 530.

[0170] The insulator 65 is preferably a single layer or a laminate of an insulator containing a so-called high-k material such as aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba,Sr)TiO3 (BST). As the miniaturization and high integration of transistors progress, problems such as leakage current may occur due to the thinning of the gate insulating film. By using a high-k material for the insulator functioning as the gate insulating film, it becomes possible to reduce the gate voltage during transistor operation while maintaining the physical film thickness.

[0171] In particular, it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium, which is an insulating material having a function of suppressing the diffusion of impurities and oxygen (oxygen is difficult to permeate). As the insulator containing an oxide of one or both of aluminum and hafnium, it is preferable to use aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc. When the insulator 65 is formed using such a material, the insulator 65 functions as a layer that suppresses the release of oxygen from the oxide 530 and the incorporation of impurities such as hydrogen from the peripheral portion of the transistor 92 into the oxide 530.

[0172] 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 laminated with silicon oxide, silicon oxynitride, or silicon nitride and used.

[0173] Also, the insulator 63 is preferably thermally stable. For example, silicon oxide and silicon oxynitride are suitable because they are thermally stable. Further, by combining a high-k material insulator with silicon oxide or silicon oxynitride, an insulator 63 having a laminated structure that is thermally stable and has a high relative permittivity can be obtained.

[0174] In transistors 92 in FIGS. 9A and 9B, insulator 63, insulator 65, and insulator 67 are shown as a second gate insulating film having a three-layer stacked structure. However, the second gate insulating film may have a single-layer, two-layer, or four-layer or more stacked structure. In that case, it is not limited to a stacked structure made of the same material, and a stacked structure made of different materials may also be used.

[0175] For transistor 92, a metal oxide that functions as an oxide semiconductor is used for oxide 530 including a channel formation region. Note that the oxide semiconductor preferably contains at least one of In and Zn. For example, as oxide 530, a metal oxide such as an In-M-Zn oxide (element M is one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used.

[0176] The formation of the metal oxide that functions as an oxide semiconductor may be performed by a sputtering method or an ALD (Atomic Layer Deposition) method. Note that the metal oxide that functions as an oxide semiconductor will be described in detail in other embodiments.

[0177] In addition, for the metal oxide that functions as a channel formation region in oxide 530, it is preferable to use one having a band gap of 2 eV or more, preferably 2.5 eV or more. By using a metal oxide with a large band gap in this way, the off-current of the transistor can be reduced.

[0178] Oxide 530 has oxide 530a under oxide 530b, so that the diffusion of impurities from the constituent formed below oxide 530a to oxide 530b can be suppressed.

[0179] Note that the oxide 530 preferably has a laminated structure of a plurality of oxide layers with different atomic ratios of each metal atom. Specifically, in the metal oxide used for the oxide 530a, the atomic ratio of the element M in the constituent elements is preferably larger than the atomic ratio of the element M in the constituent elements in the metal oxide used for the oxide 530b. Further, in the metal oxide used for the oxide 530a, the atomic ratio of the element M to In is preferably larger than the atomic ratio of the element M to In in the metal oxide used for the oxide 530b. Further, in the metal oxide used for the oxide 530b, the atomic ratio of In to the element M is preferably larger than the atomic ratio of In to the element M in the metal oxide used for the oxide 530a.

[0180] Further, it is preferable that the energy of the lower end of the conduction band of the oxide 530a is higher than the energy of the lower end of the conduction band of the oxide 530b. In other words, it is preferable that the electron affinity of the oxide 530a is smaller than the electron affinity of the oxide 530b.

[0181] Here, at the junction of the oxide 530a and the oxide 530b, the energy level of the lower end of the conduction band changes smoothly. In other words, it can also be said that the energy level of the lower end of the conduction band at the junction of the oxide 530a and the oxide 530b changes continuously or is continuously joined. To do this, it is preferable to lower the density of defect energy levels in the mixed layer formed at the interface between the oxide 530a and the oxide 530b.

[0182] Specifically, by having a common element (as the main component) other than oxygen, the oxide 530a and the oxide 530b can form a mixed layer with a low density of defect energy levels. For example, when the oxide 530b is an In-Ga-Zn oxide, an In-Ga-Zn oxide, a Ga-Zn oxide, gallium oxide, etc. may be used as the oxide 530a.

[0183] At this time, the main path of the carrier becomes the oxide 530b. By configuring the oxide 530a as described above, the density of defect levels at the interface between the oxide 530a and the oxide 530b can be reduced. Therefore, the influence of interface scattering on carrier conduction becomes small, and the transistor 92 can obtain a high on-current.

[0184] On the oxide 530b, a conductor 542a and a conductor 542b that function as a source electrode and a drain electrode are provided. As the conductor 542a and the conductor 542b, a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, lanthanum, or an alloy containing the above-described metal element as a component, or an alloy combining the above-described metal elements, etc. are preferably used. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, an oxide containing lanthanum and nickel, etc. Further, tantalum nitride, titanium nitride, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, an oxide containing lanthanum and nickel are preferable because they are conductive materials that are difficult to oxidize or materials that maintain conductivity even when absorbing oxygen. Furthermore, a metal nitride film such as tantalum nitride is preferable because it has a barrier property against hydrogen or oxygen.

[0185] Also, in FIGS. 9A and 9B, although the conductors 542a and 542b are shown as a single-layer structure, they may be a laminated structure of two or more layers. For example, a tantalum nitride film and a tungsten film may be laminated. Also, a titanium film and an aluminum film may be laminated. Further, 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, and a two-layer structure in which a copper film is laminated on a tungsten film may be used.

[0186] Also, a three-layer structure in which a titanium film or a titanium nitride film is provided, 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, a three-layer structure in which a molybdenum film or a molybdenum nitride film is provided, 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, and the like exist. Note that a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may be used.

[0187] Also, as shown in FIG. 9A, regions 543a and 543b may be formed as low-resistance regions at the interface between the oxide 530 and the conductor 542a (conductor 542b) and in the vicinity thereof. At this time, region 543a functions as one of the source region or the drain region, and region 543b functions as the other of the source region or the drain region. Also, a channel formation region is formed in the region sandwiched between region 543a and region 543b.

[0188] By providing the conductor 542a (conductor 542b) in contact with the oxide 530, the oxygen concentration in region 543a (region 543b) may be reduced. Also, a metal compound layer containing the metal contained in the conductor 542a (conductor 542b) and the components of the oxide 530 may be formed in region 543a (region 543b). In such a case, the carrier density in region 543a (region 543b) increases, and region 543a (region 543b) becomes a low-resistance region.

[0189] The insulator 69 is provided to cover the conductor 542a and the conductor 542b, and suppresses the oxidation of the conductor 542a and the conductor 542b. At this time, the insulator 69 may be provided to cover the side surface of the oxide 530 and contact the insulator 67.

[0190] As the insulator 69, a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, magnesium, etc. can be used. Further, as the insulator 69, silicon oxynitride or silicon nitride can also be used.

[0191] In particular, as the insulator 69, it is preferable to use aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc., which are insulators containing one or both oxides of aluminum or hafnium. In particular, hafnium aluminate has higher heat resistance than a hafnium oxide film. Therefore, it is preferable because it is difficult to crystallize in the heat treatment in a later process. Note that when the conductor 542a and the conductor 542b are made of a material having oxidation resistance or the conductivity does not significantly decrease even when oxygen is absorbed, the insulator 69 is not an essential component. It may be appropriately designed according to the required transistor characteristics.

[0192] By having the insulator 69, it is possible to suppress impurities such as water and hydrogen contained in the insulator 81 from diffusing to the oxide 530b through the insulator 545. Further, oxidation of the conductor 560 can be suppressed by the excess oxygen contained in the insulator 81.

[0193] The insulator 545 functions as a first gate insulating film. The insulator 545 is preferably formed using an insulator that contains an excessive amount of oxygen and releases oxygen by heating, similar to the insulator 67 described above.

[0194] Specifically, silicon oxide with excess oxygen, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, and silicon oxide with pores can be used. In particular, silicon oxide and silicon oxynitride are preferable because they are stable against heat.

[0195] By providing an insulator containing excess oxygen as insulator 545, oxygen can be effectively supplied from insulator 545 to the channel formation region of oxide 530b. Also, similar to insulator 67, it is preferable that the impurity concentration such as water or hydrogen in insulator 545 is reduced. The film thickness of insulator 545 is preferably 1 nm or more and 20 nm or less.

[0196] Further, in order to efficiently supply the excess oxygen possessed by insulator 545 to oxide 530, a metal oxide may be provided between insulator 545 and conductor 560. It is preferable that the metal oxide suppresses the diffusion of oxygen from insulator 545 to conductor 560. By providing a metal oxide that suppresses the diffusion of oxygen, the diffusion of excess oxygen from insulator 545 to conductor 560 is suppressed. That is, it is possible to suppress a decrease in the amount of excess oxygen supplied to oxide 530. Also, oxidation of conductor 560 by excess oxygen can be suppressed. As the metal oxide, a material that can be used for insulator 69 may be used.

[0197] Note that insulator 545 may have a stacked structure, similar to the second gate insulating film. As the miniaturization and high integration of transistors progress, problems such as leakage current may occur due to the thinning of the gate insulating film. Therefore, by forming an insulator that functions as a gate insulating film into a stacked structure of a high-k material and a thermally stable material, it is possible to reduce the gate voltage during transistor operation while maintaining the physical film thickness. Also, a stacked structure that is thermally stable and has a high relative dielectric constant can be achieved.

[0198] The conductor 560 that functions as the first gate electrode is shown as a two-layer structure in FIGS. 9A and 9B, but it may be a single-layer structure or a laminated structure of three or more layers.

[0199] For the conductor 560a, it is preferable to use a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (such as N2O, NO, NO2), and copper atoms. Alternatively, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.). Since the conductor 560a has a function of suppressing the diffusion of oxygen, it is possible to suppress the oxidation of the conductor 560b by oxygen contained in the insulator 545 and the decrease in conductivity. As the conductive material having a function of suppressing the diffusion of oxygen, for example, it is preferable to use tantalum, tantalum nitride, ruthenium, or ruthenium oxide. Further, as the conductor 560a, an oxide semiconductor applicable to the oxide 530 can be used. In that case, by forming the conductor 560b by sputtering, the electrical resistance value of the conductor 560a can be reduced to make it a conductor. This can be called an OC (Oxide Conductor) electrode.

[0200] Also, for the conductor 560b, it is preferable to use a conductive material mainly composed of tungsten, copper, or aluminum. Further, since the conductor 560b also functions as a wiring, it is preferable to use a conductor having high conductivity. For example, a conductive material mainly composed of tungsten, copper, or aluminum can be used. Also, the conductor 560b may have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the above conductive material.

[0201] Insulator 81 is provided on conductor 542a and conductor 542b via insulator 69. Insulator 81 preferably has an excess oxygen region. For example, as insulator 81, it is preferable to have silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, silicon oxide having pores, or resin, etc. In particular, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In particular, silicon oxide and silicon oxide having pores are preferable because an excess oxygen region can be easily formed in a later process.

[0202] Insulator 81 preferably has an excess oxygen region. By providing insulator 81 that releases oxygen upon heating, oxygen in insulator 81 can be efficiently supplied to oxide 530. Note that it is preferable that the concentration of impurities such as water or hydrogen in insulator 81 is reduced.

[0203] The opening of insulator 81 is formed to overlap the region between conductor 542a and conductor 542b. Thereby, conductor 560 is formed so as to be embedded in the opening of insulator 81 and the region sandwiched between conductor 542a and conductor 542b.

[0204] When miniaturizing a semiconductor device, it is required to shorten the gate length, but it is necessary to prevent the conductivity of conductor 560 from decreasing. Therefore, if the film thickness of conductor 560 is increased, conductor 560 can have a high aspect ratio shape. In the present embodiment, since conductor 560 is provided so as to be embedded in the opening of insulator 81, even if conductor 560 has a high aspect ratio shape, it can be formed without collapsing conductor 560 during the process.

[0205] The insulator 83 is preferably provided in contact with the upper surface of the insulator 81, the upper surface of the conductor 560, and the upper surface of the insulator 545. By forming the insulator 83 by sputtering, an excess oxygen region can be provided in the insulator 545 and the insulator 81. Thereby, oxygen can be supplied from the excess oxygen region into the oxide 530.

[0206] For example, as the insulator 83, a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, or magnesium can be used.

[0207] In particular, aluminum oxide has high barrier properties and can suppress the diffusion of hydrogen and nitrogen even in a thin film of 0.5 nm or more and 3.0 nm or less. Therefore, aluminum oxide formed by sputtering can function as an oxygen supply source and also as a barrier film for impurities such as hydrogen.

[0208] Also, it is preferable to provide an insulator 85 that functions as an interlayer film on the insulator 83. Similar to the insulator 67, etc., the insulator 85 preferably has a reduced concentration of impurities such as water or hydrogen in the film.

[0209] Also, conductors 540a and 540b are disposed in openings formed in the insulator 85, the insulator 83, the insulator 81, and the insulator 69. The conductors 540a and 540b are provided to face each other with the conductor 560 interposed therebetween.

[0210] An insulator 87 is provided on the insulator 85. It is preferable to use a material that is barrier against oxygen and hydrogen for the insulator 87. Therefore, the same material as the insulator 49 can be used for the insulator 87.

[0211] In particular, silicon nitride has a high blocking effect of not allowing the film to permeate both oxygen and impurities such as hydrogen and moisture that are factors causing fluctuations in the electrical characteristics of transistors. Therefore, silicon nitride can prevent the incorporation of impurities such as hydrogen and moisture into the transistor 92 during and after the manufacturing process of the transistor. In addition, the release of oxygen from the oxide constituting the transistor 92 can be suppressed. Therefore, it is suitable to be used as a protective film for the transistor 92.

[0212] Also, after the formation of the transistor 92, an opening may be formed so as to surround the transistor 92, and an insulator having a high barrier property against hydrogen or water may be formed so as to cover the opening. By wrapping the transistor 92 with the above-described insulator having a high barrier property, the intrusion of moisture and hydrogen from the outside can be prevented. Alternatively, a plurality of transistors 92 may be collectively wrapped with an insulator having a high barrier property against hydrogen or water. When forming an opening so as to surround the transistor 92, for example, when an opening reaching the insulator 65 or the insulator 49 is formed and the above-described insulator having a high barrier property is formed in contact with the insulator 65 or the insulator 49, a part of the manufacturing process of the transistor 92 can be also served, which is preferable. Therefore, although not shown in FIG. 8, it is preferable to form the above-described insulator having a high barrier property so as to wrap the side wall of the conductor 56 or the conductor 71. Note that, as the insulator having a high barrier property against hydrogen or water, for example, the same material as that of the insulator 65 or the insulator 49 may be used.

[0213] By using this configuration, in a semiconductor device using a transistor having an oxide semiconductor, miniaturization or high integration can be achieved.

[0214] As substrates that can be used in the semiconductor device according to one aspect of the present invention, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, a metal substrate (for example, a stainless steel substrate, a substrate having a stainless steel foil, a tungsten substrate, a substrate having a tungsten foil, etc.), a semiconductor substrate (for example, a single crystal semiconductor substrate, a polycrystalline semiconductor substrate, or a compound semiconductor substrate, etc.), an SOI (SOI: Silicon on Insulator) substrate, etc. can be used. Further, a plastic substrate having heat resistance capable of withstanding the processing temperature of the present embodiment may be used. As an example of the glass substrate, there are barium borosilicate glass, aluminosilicate glass, or aluminoborosilicate glass, or soda lime glass, etc. In addition, crystallized glass, etc. can be used.

[0215] Alternatively, as the substrate, a flexible substrate, a laminated film, paper containing a fibrous material, or a base film, etc. can be used. Examples of the flexible substrate, the laminated film, the base film, etc. include the following. For example, plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Alternatively, as an example, there is a synthetic resin such as acrylic. Alternatively, as an example, there are polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride, etc. Alternatively, as an example, there are polyamide, polyimide, aramid resin, epoxy resin, inorganic vapor deposition film, or papers, etc. In particular, by manufacturing a transistor using a semiconductor substrate, a single crystal substrate, or an SOI substrate, etc., a transistor with little variation in characteristics, size, or shape, high current capacity, and small size can be manufactured. When a circuit is configured with such a transistor, power consumption reduction of the circuit or high integration of the circuit can be achieved.

[0216] Further, a flexible substrate may be used as the substrate, and transistors, resistors, and / or capacitors may be formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate and transistors, resistors, and / or capacitors. After partially or fully completing a semiconductor device on the release layer, the release layer can be separated from the substrate and used for transfer to another substrate. At this time, transistors, resistors, and / or capacitors can be transferred onto a substrate with poor heat resistance or a flexible substrate. Note that, for the above-described release layer, for example, a stacked structure of inorganic films such as a tungsten film and a silicon oxide film, a structure in which an organic resin film such as polyimide is formed on a substrate, a silicon film containing hydrogen, or the like can be used.

[0217] That is, a semiconductor device may be formed on a certain substrate and then transferred to another substrate. As an example of the substrate to which the semiconductor device is transferred, in addition to the substrate on which the above-described transistors can be formed, a paper substrate, a cellophane substrate, an aramid film substrate, a polyimide film substrate, a stone substrate, a wood substrate, a cloth substrate (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester), or regenerated fibers (acetate, cupra, rayon, regenerated polyester), etc.), a leather substrate, or a rubber substrate. By using these substrates, it is possible to manufacture a flexible semiconductor device, manufacture a semiconductor device that is difficult to break, impart heat resistance, reduce weight, or reduce thickness.

[0218] By providing a semiconductor device on a flexible substrate, it is possible to suppress an increase in weight and provide a semiconductor device that is difficult to break.

[0219] <Modification Example 1 of Transistor> The transistor 92A shown in FIGS. 10A to 10C is a modification of the transistor 92 having the configuration shown in FIGS. 9A and 9B. FIG. 10B is a cross-sectional view of the transistor 92A in the channel length direction, and FIG. 10C is a cross-sectional view of the transistor 92A in the channel width direction.

[0220] The transistor 92A having the structure shown in FIGS. 10A to 10C is different from the transistor 92 having the structure shown in FIGS. 9A and 9B in that it has the insulator 552, the insulator 48, and the insulator 51. Also, the transistor 92A is different from the transistor 92 having the structure shown in FIGS. 9A and 9B in that the insulator 552 is provided in contact with the side surface of the conductor 540a and the insulator 552 is provided in contact with the side surface of the conductor 540b. Further, the transistor 92A is different from the transistor 92 having the structure shown in FIGS. 9A and 9B in that it does not have the insulator 63.

[0221] In the transistor 92A having the structure shown in FIGS. 10A to 10C, the insulator 48 is provided on the insulator 47. Also, the insulator 51 is provided on the insulator 83 and on the insulator 48.

[0222] In the transistor 92A having the structure shown in FIGS. 10A to 10C, the insulators 49, 61, 65, 67, 69, 81, and 83 are patterned, and the insulator 51 is configured to cover these. That is, the insulator 51 is in contact with the upper surface of the insulator 83, the side surface of the insulator 83, the side surface of the insulator 81, the side surface of the insulator 69, the side surface of the insulator 67, the side surface of the insulator 65, the side surface of the insulator 61, the side surface of the insulator 49, and the upper surface of the insulator 48, respectively. Thereby, the oxide 530 etc. are isolated from the outside by the insulator 51 and the insulator 48.

[0223] The insulators 48 and 51 preferably have a high function of suppressing the diffusion of hydrogen (for example, at least one of hydrogen atoms, hydrogen molecules, etc.) or water molecules. For example, it is preferable to use silicon nitride or silicon oxynitride, which are materials having high hydrogen barrier properties, as the insulators 48 and 51. Thereby, it is possible to suppress the diffusion of hydrogen etc. into the oxide 530, so that the deterioration of the characteristics of the transistor 92A can be suppressed. Therefore, the reliability of the semiconductor device according to one aspect of the present invention can be enhanced.

[0224] The insulator 552 is provided in contact with the insulators 85, 51, 83, 81, and 69. The insulator 552 preferably has a function of suppressing the diffusion of hydrogen or water molecules. For example, as the insulator 552, it is preferable to use an insulator such as silicon nitride, aluminum oxide, or silicon oxynitride, which is a material having high hydrogen barrier properties. In particular, since silicon nitride is a material having high hydrogen barrier properties, it is suitable for use as the insulator 552. By using a material having high hydrogen barrier properties as the insulator 552, it is possible to suppress the diffusion of impurities such as water or hydrogen from the insulator 81 or the like through the conductors 540a and 540b to the oxide 530. In addition, it is possible to suppress the absorption of oxygen contained in the insulator 81 by the conductors 540a and 540b. As described above, the reliability of the semiconductor device according to one aspect of the present invention can be enhanced.

[0225] <Modification Example 2 of Transistor> A configuration example of the transistor 92B will be described with reference to FIGS. 11A, 11B, and 11C. FIG. 11A is a top view of the transistor 92B. FIG. 11B is a cross-sectional view of the L1-L2 portion indicated by the dashed line in FIG. 11A. FIG. 11C is a cross-sectional view of the W1-W2 portion indicated by the dashed line in FIG. 11A. In the top view of FIG. 11A, the description of some elements is omitted for clarity of the drawing.

[0226] The transistor 92B is a modification of the transistor 92 and is a transistor that can be replaced with the transistor 92. Therefore, in order to prevent repetition of the description, mainly the differences from the transistor 92 of the transistor 92B will be described.

[0227] The conductor 560 that functions as the first gate electrode has the conductor 560a and the conductor 560b on the conductor 560a. As the conductor 560a, it is preferable to use a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. Alternatively, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.).

[0228] Since the conductor 560a has the function of suppressing the diffusion of oxygen, the material selectivity of the conductor 560b can be improved. That is, by having the conductor 560a, the oxidation of the conductor 560b can be suppressed, and it is possible to prevent the conductivity from decreasing.

[0229] Also, it is preferable to provide an insulator 69 so as to cover the upper surface and the side surface of the conductor 560 and the side surface of the insulator 545. The insulator 69 may be made of an insulating material having a function of suppressing the diffusion of impurities such as water or hydrogen and oxygen. For example, it is preferable to use silicon nitride or the like. In addition, other materials such as magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, or tantalum oxide, or silicon oxynitride can also be used.

[0230] By providing the insulator 69, the oxidation of the conductor 560 can be suppressed. Also, by having the insulator 69, it is possible to suppress the diffusion of impurities such as water and hydrogen that the insulator 81 has to the transistor 92B.

[0231] Since the transistor 92B has the conductor 560 overlapping a part of the conductor 542a and a part of the conductor 542b, the parasitic capacitance is more likely to be larger than that of the transistor 92. Therefore, the operating frequency tends to be lower than that of the transistor 92. However, since the process of providing an opening in the insulator 81 or the like and embedding the conductor 560, the insulator 545, etc. is unnecessary, the productivity is high compared to the transistor 92.

[0232] FIG. 12 is a diagram for explaining a configuration example of a display device different from FIG. 8. In the configuration of the invention described below, the same reference numerals are commonly used among different drawings for the same part or parts having the same function, and the repeated description thereof is omitted. Also, when referring to the same function, the hatch pattern may be the same, and in some cases, no reference numeral may be attached.

[0233] FIG. 12 is different in that a conductor 54 functioning as the other electrode of the capacitor 95 further covers a part of the side surface of the inorganic light-emitting element 100 via an insulator 41. Therefore, both the one and the other of the electrodes of the capacitor 95 function as reflective electrodes. As an example, when the insulator 47a has translucency, the light L4 emitted from the inorganic light-emitting element 100 can contribute to display through the substrate 11 because the other of the electrodes of the capacitor 95 covering a part of the side surface of the inorganic light-emitting element 100 functions as a reflective electrode. Further, the light L5 emitted from the inorganic light-emitting element 100 can contribute to display through the substrate 11 because the other of the electrodes of the capacitor 95 covering a part of the side surface of the inorganic light-emitting element 100 of an adjacent pixel functions as a reflective electrode.

[0234] When the facing sides of the one and the other of the electrodes of the capacitor 95 are defined as the inner sides of the one and the other of the electrodes of the capacitor 95, the non-facing surfaces of the one and the other of the electrodes of the capacitor 95 can be defined as the outer sides.

[0235] The light L2 emitted from the inorganic light-emitting element 100 can be reflected by the one of the electrodes of the capacitor 95 and contribute to display. The light L4 emitted from the inorganic light-emitting element 100 can be reflected by the inner side of the other of the electrodes of the capacitor 95 and contribute to display. The light L5 emitted from the inorganic light-emitting element 100 can be reflected by the outer side of the other of the electrodes of the capacitor 95 of an adjacent pixel and contribute to display. Therefore, the light emitted from the inorganic light-emitting element 100 can be effectively utilized. Further, since the lights L4 and L5 are reflected by the capacitor 95 functioning as a reflective electrode and emitted from the display surface of the display device, they have the effect of widening the viewing angle.

[0236] Also, as another example, the conductor 54 may cover all of the inorganic light-emitting element 100 except for the display surface from which the light of the inorganic light-emitting element 100 is emitted. By covering all of the inorganic light-emitting element 100 except for the display surface from which the light of the inorganic light-emitting element 100 is emitted, the light emitted by the inorganic light-emitting element 100 is emitted from the display surface. Therefore, the light extraction efficiency of the inorganic light-emitting element 100 is improved, and the light reflected by the side surface is effective in improving the viewing angle. Furthermore, it is possible to reduce fluctuations in the electrical characteristics of the transistor that occur when the transistor is irradiated with light.

[0237] Note that in FIG. 8, the insulator 47a may have translucency or may be a colored layer. Also, a part of the conductor 54 preferably has a region that overlaps with the insulator 41 and the metal oxynitride film 20.

[0238] This embodiment can be appropriately combined with other embodiments and examples.

[0239] (Embodiment 3) In this embodiment, a configuration example of a display device using the inorganic light-emitting element described in the above embodiment will be described.

[0240] The display device of this embodiment has a function of displaying an image using an inorganic light-emitting element. In this embodiment, in particular, an example in which a micro light-emitting diode (hereinafter also referred to as a micro LED) is used as the inorganic light-emitting element will be described.

[0241] By using a micro LED as the display element, the power consumption of the display device can be reduced. Also, the display device can be made thinner and lighter. Also, a display device using a micro LED as the display element can enhance the display quality because it has high contrast and a wide viewing angle.

[0242] The area of the region that emits the light of the micro LED is preferably 1 mm 2 or less, more preferably 10000 μm 2 or less, and still more preferably 3000 μm 2 or less, and still more preferably 700 μm 2The following is more preferable.

[0243] FIG. 13A shows a configuration example of a display device 400 using an inorganic light-emitting element. The display device 400 includes a pixel portion 401, a driving circuit 402, and a driving circuit 403.

[0244] The pixel portion 401 is composed of a plurality of pixels pix. Each pixel pix is connected to a wiring SL and a wiring GL. Further, each wiring GL is connected to the driving circuit 402, and each wiring SL is connected to the driving circuit 403. A selection signal is supplied to the wiring GL, and a video signal is supplied to the wiring SL.

[0245] The driving circuit 402 has a function of supplying a selection signal to the pixel pix. Specifically, the driving circuit 402 has a function of supplying a selection signal to the wiring GL, and the wiring GL has a function of transmitting the selection signal output from the driving circuit 402 to the pixel pix. Note that the driving circuit 402 can be called a gate-side driving circuit or a gate driver, and the wiring GL can also be called a selection signal line, a gate line, or the like.

[0246] The driving circuit 403 has a function of supplying a video signal to the pixel pix. Specifically, the driving circuit 403 has a function of supplying a video signal to the wiring SL, and the wiring SL has a function of transmitting the video signal output from the driving circuit 403 to the pixel pix. Note that the driving circuit 403 can be called a source-side driving circuit or a source driver, and the wiring SL can also be called a video signal line, a source line, or the like.

[0247] FIG. 13B shows a configuration example of a pixel pix using an inorganic light-emitting element as a display element. The pixel pix shown in FIG. 13B includes a transistor 91, a transistor 92, a capacitor 95, and an inorganic light-emitting element 100. Here, the transistors 91 and 92 are of n-channel type, but the polarities of the transistors can be changed as appropriate. The inorganic light-emitting element described in the above embodiment can be used for the inorganic light-emitting element 100.

[0248] The gate of transistor 91 is connected to wiring GL, one of the source or drain is connected to the gate of transistor 92 and one electrode of capacitor 95, and the other of the source or drain is connected to wiring SL. One of the source or drain of transistor 92 is connected to the other electrode of capacitor 95 and one electrode of inorganic light-emitting element 100, and the other of the source or drain is connected to the wiring to which potential Va is supplied. The other electrode of inorganic light-emitting element 100 is connected to the wiring to which potential Vc is supplied. A node connected to one of the source or drain of transistor 91, the gate of transistor 92, and one electrode of capacitor 95 is defined as node N96. Also, a node connected to one of the source or drain of transistor 92, the other electrode of capacitor 95, and one electrode of inorganic light-emitting element 100 is defined as node N97.

[0249] Here, the case where potential Va is the high power supply potential and potential Vc is the low power supply potential will be described. Potentials Va and Vc can each be a common potential for a plurality of pixels pix. Also, capacitor 95 has a function as a holding capacitor for holding the potential of node N96.

[0250] Transistor 91 has a function of controlling the supply of the potential of wiring SL to node N97. Specifically, by controlling the potential of wiring GL to turn on transistor 91, the potential of wiring SL corresponding to the video signal is supplied to node N96, and writing to pixel pix is performed. Thereafter, by controlling the potential of wiring GL to turn off transistor 91, the potential of node N96 is held.

[0251] Then, the amount of current flowing between the source and drain of transistor 92 is controlled according to the voltage between nodes N96 and N97, and inorganic light-emitting element 100 emits light with a luminance corresponding to the amount of current. Thereby, the gradation of pixel pix can be controlled. Note that transistor 92 is preferably operated in the saturation region.

[0252] Here, the transistor 91 and the transistor 92 may be provided in the same layer or may be provided in a stacked manner. By providing the transistor 91 and the transistor 92 in the same layer, the transistor 91 and the transistor 92 can be fabricated simultaneously, and the manufacturing process of the display device can be shortened. Alternatively, by stacking and providing the transistor 91 and the transistor 92, the integration degree of the display device can be increased.

[0253] Also, as shown in FIG. 13B, a configuration having two transistors (91 and 92) in the pixel pix is preferable. However, one aspect of the present invention is not limited to this, and a configuration having three or more transistors in the pixel pix may be employed.

[0254] FIG. 13C is a configuration example of a pixel pix using an inorganic light-emitting element as a display element, which is different from FIG. 13B. The pixel pix shown in FIG. 13C includes a transistor 91, a transistor 92, a transistor 93, a capacitor 95, and an inorganic light-emitting element 100. That is, the pixel pix shown in FIG. 13C is a pixel in which a transistor 93 for monitoring the amount of current flowing through the transistor 92 is added to the pixel pix shown in FIG. 13B.

[0255] The gate of transistor 91 is connected to wiring GL, one of the source or drain is connected to the gate of transistor 92 and one electrode of capacitor 95, and the other of the source or drain is connected to wiring SL. One of the source or drain of transistor 92 is connected to the other electrode of capacitor 95, one electrode of inorganic light-emitting element 100, and one of the source or drain of transistor 93, and the other of the source or drain is connected to the wiring to which potential Va is supplied. The other electrode of inorganic light-emitting element 100 is connected to the wiring to which potential Vc is supplied. The gate of transistor 93 is connected to wiring GL, and the other of the source or drain is connected to monitor line ML. The node connected to one of the source or drain of transistor 91, the gate of transistor 92, and one electrode of capacitor 95 is defined as node N96. Also, the node connected to one of the source or drain of transistor 92, the other electrode of capacitor 95, one electrode of inorganic light-emitting element LE, and one of the source or drain of transistor 93 is defined as node N97.

[0256] By sequentially performing the above operations for each wiring GL, an image for the first frame can be displayed.

[0257] Note that for the selection of wiring GL, either the progressive method or the interlace method may be used. Also, for the supply of the video signal to wiring SL, it may be performed using dot sequential driving in which the video signal is sequentially supplied to wiring SL, or line sequential driving in which the video signal is supplied to all wiring SL at once. Also, the video signal may be supplied in order for each of a plurality of wiring SL.

[0258] Thereafter, in the second frame period, the image is displayed by the same operation as in the first frame period. As a result, the image displayed on pixel section 401 is rewritten.

[0259] As the semiconductor used for the transistor included in pixel pix, elements of Group 14 such as silicon and germanium, compound semiconductors such as gallium arsenide, organic semiconductors, metal oxides, etc. can be used. Further, the semiconductor may be an amorphous semiconductor (such as an amorphous semiconductor, a microcrystalline semiconductor, a polycrystalline semiconductor, etc.), or may be a single crystal semiconductor.

[0260] The transistor included in pixel pix preferably includes an amorphous semiconductor, particularly hydrogenated amorphous silicon (a-Si:H), in the channel formation region. Since a transistor using an amorphous semiconductor can easily cope with a larger area of the substrate, for example, when manufacturing a large-screen display device capable of supporting 4K2K broadcast, 8K4K broadcast, etc., the manufacturing process can be simplified.

[0261] Further, for the transistor included in pixel pix, a transistor (OS transistor) including a metal oxide in the channel formation region can also be used. The OS transistor has a higher field-effect mobility compared to a transistor using hydrogenated amorphous silicon. Also, a crystallization process that was necessary for a transistor using polycrystalline silicon, etc. is not required.

[0262] Further, since the off-current of the OS transistor is extremely small, when using the OS transistor as transistor 91, the video signal can be held in pixel pix for an extremely long period. Thereby, during a period when there is no change in the video displayed in pixel section 401, or during a period when the change is below a certain level, the update frequency of the video signal can be set extremely low. The update frequency of the video signal can be set, for example, to once or less per 0.1 second, once or less per second, once or less per 10 seconds, etc. In particular, when a large number of pixels pix are provided corresponding to 4K2K broadcast, 8K4K broadcast, etc., it is effective to reduce power consumption by omitting the update of the video signal.

[0263] FIG. 14 is a diagram for explaining a display device. The display device includes a substrate 10, a substrate 11, a functional layer 12, a metal oxynitride film 20, a pixel portion 401, a plurality of terminals Vp, and a plurality of terminals Vc. The pixel portion 401 includes a plurality of pixels Pix. The metal oxynitride film 20 functions as a common electrode, and a plurality of pixels Pix are formed on the common electrode. It is preferable that a cathode potential is applied to the common electrode.

[0264] The plurality of terminals Vp are terminals for applying signals to the respective pixels Pix. Some of the terminals Vp are connected to the wiring SL, and the remaining terminals VP are connected to the wiring GL. The plurality of terminals Vc are connected to the metal oxynitride film 20 that functions as a common electrode. The cathode potential of the inorganic light-emitting element 100 included in each pixel Pix can be prevented from floating due to the influence of the resistance component of the metal oxynitride film 20 by having a plurality of terminals Vc.

[0265] The display device further includes an inorganic light-emitting element formation layer 100L where the inorganic light-emitting element 100 is formed, a capacitor formation layer 95L where a capacitor 95 is formed, and a transistor formation layer 92L where a transistor 92 is formed. Each pixel Pix includes an inorganic light-emitting element 100 formed in the inorganic light-emitting element formation layer 100L, a capacitor 95 formed in the capacitor formation layer 95L, and a transistor 92 formed in the transistor formation layer 92L. The terminal Vp is electrically connected to the wiring in the transistor formation layer.

[0266] Bumps can be provided on the terminals Vp and Vc. Although not shown in FIG. 14, it is preferable to bond the drive circuits 402 and 403. Therefore, a small and high-definition display device can be fabricated. Also, by bonding the drive circuits 402 and 403 via bumps, the number of components can be reduced. The above-described display device can be used in a head-mounted display (HMD). As an example, it is preferably used in a goggle-type display device or a glasses-type display device.

[0267] FIG. 15A shows a perspective view of the glasses-type information terminal 900. The information terminal 900 includes a pair of display panels 901, a pair of housings (housing 902a, housing 902b), a pair of optical members 903, a pair of mounting parts 904, and the like.

[0268] The information terminal 900 can project the image displayed on the display panel 901 onto the display area 906 of the optical member 903. Further, since the optical member 903 has translucency, the user can view the image displayed in the display area 906 superimposed on the transmitted image viewed through the optical member 903. Therefore, the information terminal 900 is an information terminal capable of AR display or VR display. Note that the display unit 14 described in the previous embodiment may include not only the display panel 901 but also the optical member 903 including the display area 906, and an optical system having a lens 911, a reflector 912, and a reflecting surface 913, which will be described later. As the display panel 901, it is preferable to use a micro LED display. Note that the display panel 901 can use an organic EL display, an inorganic EL display, a liquid crystal display, or the like. When the display panel 901 uses a liquid crystal display, the inorganic light-emitting element 100 can be used as a light source functioning as a backlight.

[0269] In addition, the information terminal 900 is provided with a pair of cameras 905 capable of imaging the front and a pair of cameras 909 capable of imaging the user side. The camera 905 is a part of the components of the camera module, and the camera 909 is a part of the components of the camera module. It is preferable to provide a plurality of cameras 905 in the information terminal 900 because materials and cooking utensils can be three-dimensionally imaged. However, the camera 905 in this embodiment is not limited to this. The number of cameras 905 provided in the information terminal 900 may be one. In this case, the camera 905 may be provided at the center of the front surface of the information terminal 900, or may be provided on the front surface of one of the housings 902a and 902b. Also, two cameras 905 can be provided on the front surfaces of the housings 902a and 902b, respectively.

[0270] The camera 909 can detect the user's line of sight. Therefore, it is preferable to provide two cameras 909, one for the right eye and one for the left eye. However, if one camera can detect the line of sight of both eyes, only one camera 909 may be sufficient. Also, the camera 909 may be an infrared camera that can detect infrared rays.

[0271] In addition, the housing 902a has a wireless communication device 907 and can supply a video signal or the like to the housing 902. Also, the wireless communication device 907 preferably has a communication module and communicates with a database. Instead of or in addition to the wireless communication device 907, a connector may be provided that can connect a cable 910 to which a video signal or a power potential is supplied. Further, the housing 902 may be provided with an acceleration sensor, a gyro sensor, etc., to detect the orientation of the user's head and display an image corresponding to the orientation in the display area 906. Also, it is preferable that the housing 902 is provided with a battery and can be charged wirelessly or by wire. The battery is preferably incorporated in the pair of mounting parts 904.

[0272] Also, an integrated circuit 908 is provided in the housing 902b. Although not shown in FIG. 15, the integrated circuit 908 has a controller, a processor, a memory, an audio controller, etc., and has a camera 905, a wireless communication device 907, a pair of display panels 901, a microphone, a speaker, etc. The information terminal 900 preferably has functions such as controlling various components and generating images. The integrated circuit 908 preferably has a function of generating a composite image for AR display or VR display.

[0273] The wireless communication device 907 can communicate data with external devices. For example, data transmitted from the outside can be output to the integrated circuit 908, and the integrated circuit 908 can also generate image data for AR display or VR display based on the data. Examples of data transmitted from the outside include images acquired by the camera 905 being transmitted to a database and data analyzed by the database.

[0274] Subsequently, with reference to FIG. 15B, a method for projecting an image onto the display area 906 of the information terminal 900 will be described. Inside the housing 902, a display panel 901, a lens 911, and a reflector 912 are provided. Also, a reflecting surface 913 that functions as a half mirror is provided at a portion of the optical member 903 corresponding to the display area 906.

[0275] Light 915 emitted from the display panel 901 passes through the lens 911 and is reflected by the reflector 912 toward the optical member 903. Inside the optical member 903, the light 915 repeatedly undergoes total reflection at the end face of the optical member 903 and reaches the reflecting surface 913, where an image is projected onto the reflecting surface 913. As a result, the user can visually recognize both the light 915 reflected by the reflecting surface 913 and the transmitted light 916 that has passed through the optical member 903 (including the reflecting surface 913).

[0276] FIG. 15B shows an example in which the reflector 912 and the reflecting surface 913 each have a curved surface. This can increase the degree of freedom in optical design and reduce the thickness of the optical member 903 compared to the case where they are flat. Note that the reflector 912 and the reflecting surface 913 may be flat.

[0277] For the reflector 912, a member having a mirror surface can be used, and it is preferably highly reflective. Also, as the reflecting surface 913, a half mirror utilizing the reflection of a metal film may be used, but using a prism or the like that utilizes total reflection can increase the transmittance of the transmitted light 916.

[0278] Here, it is preferable that the housing 902 has a mechanism for adjusting the distance between the lens 911 and the display panel 901 and their angles. Thereby, it becomes possible to perform fine adjustment, image enlargement, reduction, etc. For example, one or both of the lens 911 and the display panel 901 may be configured to be movable in the optical axis direction.

[0279] Also, it is preferable that the housing 902 has a mechanism for adjusting the angle of the reflector 912. By changing the angle of the reflector 912, it becomes possible to change the position of the display area 906 where the image is displayed. Thereby, it becomes possible to arrange the display area 906 at an optimal position according to the position of the user's eyes.

[0280] The display device according to one aspect of the present invention can be applied to the display panel 901. Therefore, an information terminal 900 capable of extremely high-precision display can be obtained.

[0281] This embodiment can be appropriately combined with the descriptions of other embodiments and examples.

[0282] (Embodiment 4) In this embodiment, an electronic device according to one aspect of the present invention using the display device shown in the previous embodiment will be described with reference to the drawings.

[0283] Examples of the electronic device include relatively large-screen electronic devices such as television sets, desktop or notebook personal computers, monitors for computers, digital signage, and large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, portable information terminals, and audio playback devices.

[0284] An electronic device according to an aspect of the present invention may have an antenna. By receiving a signal with the antenna, the display unit can display images, information, etc. Note that since the display unit can be configured by a display device, the display unit can also be referred to as a display device. Further, when the electronic device has an antenna and a secondary battery, the antenna may be used for wireless power transmission.

[0285] An electronic device according to an aspect of the present invention may have a sensor (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, voice, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays).

[0286] An electronic device according to an aspect of the present invention can have various functions. For example, it can have a function of displaying various information (such as still images, moving images, text images, etc.) on the display unit, a touch panel function, a function of displaying a calendar, date or time, etc., a function of executing various software (programs), a wireless communication function, a function of reading a program or data recorded on a recording medium, etc.

[0287] An example of a television device is shown in FIG. 16A. In the television device 7100, a display unit 7000 is incorporated in a housing 7101. Here, a configuration in which the housing 7101 is supported by a stand 7103 is shown.

[0288] The display device according to an aspect of the present invention can be applied to the display unit 7000.

[0289] The operation of the television apparatus 7100 shown in FIG. 16A can be performed by operation switches provided in the housing 7101 or by a separate remote control operation unit 7111. Alternatively, the display unit 7000 may be provided with a touch sensor, and the operation may be performed by touching the display unit 7000 with a finger, a slider, or the like. The remote control operation unit 7111 may have a display unit for displaying information output from the remote control operation unit 7111. Channel and volume operations can be performed by operation keys or a touch panel provided in the remote control operation unit 7111, and the video displayed on the display unit 7000 can be operated.

[0290] Note that the television apparatus 7100 has a configuration including a receiver and a modem. General television broadcasts can be received by the receiver. Also, by connecting to a wired or wireless communication network via the modem, one-way (from sender to receiver) or two-way (between sender and receiver, between receivers, etc.) information communication can be performed.

[0291] FIG. 16B shows a notebook personal computer 7200. The notebook personal computer 7200 has a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. The display unit 7000 is incorporated in the housing 7211.

[0292] The display device according to one aspect of the present invention can be applied to the display unit 7000.

[0293] FIGS. 16C and 16D show an example of digital signage.

[0294] The digital signage 7300 shown in FIG. 16C has a housing 7301, a display unit 7000, a speaker 7303, and the like. Furthermore, it can have an LED lamp, operation keys (including a power switch or an operation switch), connection terminals, various sensors, a microphone, and the like.

[0295] In addition, FIG. 16D shows a digital signage 7400 attached to a cylindrical column 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the column 7401.

[0296] In FIGS. 16C and 16D, the display device according to one aspect of the present invention can be applied to the display unit 7000.

[0297] The larger the display unit 7000 is, the more information can be provided at one time. Also, the larger the display unit 7000 is, the more easily it catches people's eyes, and for example, the advertising effect can be enhanced.

[0298] By applying a touch panel to the display unit 7000, not only can an image or video be displayed on the display unit 7000, but also the user can operate it intuitively, which is preferable. Also, when used for applications such as providing route information and traffic information, the usability can be improved by intuitive operation.

[0299] Also, as shown in FIGS. 16C and 16D, it is preferable that the digital signage 7300 or the digital signage 7400 can be linked with an information terminal 7311 or an information terminal 7411 such as a smartphone held by the user by wireless communication. For example, the information of the advertisement displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. Also, by operating the information terminal 7311 or the information terminal 7411, the display of the display unit 7000 can be switched.

[0300] Also, a game can be executed on the digital signage 7300 or the digital signage 7400 using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller). Thereby, an unspecified number of users can participate in the game and enjoy it at the same time.

[0301] In addition, the display device according to one aspect of the present invention can be incorporated along the inner wall or outer wall of a house or building, or the curved surface of the interior or exterior of a vehicle. FIG. 16E shows an example of mounting the display device according to one aspect of the present invention on a vehicle.

[0302] FIG. 16E shows a configuration example of a vehicle equipped with a display unit 5001. As the display unit 5001, the display device according to one aspect of the present invention can be used. Although FIG. 16E shows an example in which the display unit 5001 is mounted on a vehicle with a right-hand steering wheel, it is not particularly limited and can also be mounted on a vehicle with a left-hand steering wheel. In this case, the left-right arrangement of the configuration shown in FIG. 16E is changed.

[0303] FIG. 16E shows a dashboard 5002, a steering wheel 5003, a windshield 5004, etc. arranged around the driver's seat and the passenger seat. The display unit 5001 is arranged at a predetermined position on the dashboard 5002, specifically around the driver, and has a substantially T shape. FIG. 16E shows an example in which one display unit 5001 formed using a plurality of display panels 5007 (display panels 5007a, 5007b, 5007c, 5007d) is provided along the dashboard 5002, but the display unit 5001 may be arranged separately at a plurality of locations.

[0304] Note that the plurality of display panels 5007 may have flexibility. In this case, the display unit 5001 can be processed into a complex shape, and configurations such as providing the display unit 5001 along the curved surface of the dashboard 5002 or the like, and configurations in which the display area of the display unit 5001 is not provided at the connection part of the steering wheel, the display part of the instrument, the air outlet 5006, etc. can be easily realized.

[0305] In addition, a plurality of cameras 5005 for photographing the rear side situation may be provided outside the vehicle. FIG. 16E shows an example in which the camera 5005 is installed instead of the side mirror, but both the side mirror and the camera may be installed.

[0306] As the camera 5005, a CCD camera, a CMOS camera, etc. can be used. In addition to these cameras, an infrared camera may be combined and used. Since the output level of the infrared camera becomes higher as the temperature of the subject is higher, a living body such as a person or an animal can be detected or extracted.

[0307] The image captured by the camera 5005 can be output to any one or more of the display panels 5007. The display unit 5001 is mainly used to assist in driving the vehicle. By photographing the rear side situation with a wide angle of view by the camera 5005 and displaying the image on the display panel 5007, the driver's blind spot area can be visually recognized, and the occurrence of an accident can be prevented.

[0308] In addition, a distance image sensor may be provided on the roof of the vehicle or the like, and the image obtained by the distance image sensor may be displayed on the display unit 5001. As the distance image sensor, an image sensor, a lidar (Light Detection and Ranging), etc. can be used. By displaying the image obtained by the image sensor and the image obtained by the distance image sensor on the display unit 5001, more information can be provided to the driver, and driving can be assisted.

[0309] In addition, the display unit 5001 may have a function of displaying map information, traffic information, TV video, DVD video, etc. For example, the display panels 5007a, 5007b, 5007c, 5007d can be used as one display screen to display the map information largely. Note that the number of the display panels 5007 can be increased according to the video to be displayed.

[0310] In addition, the images displayed on the display panels 5007a, 5007b, 5007c, and 5007d can be freely set according to the driver's preferences. For example, TV images and DVD images can be displayed on the left display panel 5007d, map information can be displayed on the central display panel 5007b, instruments can be displayed on the right display panel 5007c, and audio can be displayed on the display panel 5007a near the transmission gear (between the driver's seat and the passenger seat). Also, by combining the plurality of display panels 5007, a fail-safe function can be added to the display unit 5001. For example, even if a certain display panel 5007 fails for some reason, the display area can be changed and display can be performed using other display panels 5007.

[0311] This embodiment can be appropriately combined with the descriptions of other embodiments and examples.

Example

[0312] In this example, the results of evaluating the crystallinity and orientation of the metal nitride film formed on the metal oxynitride film using the method shown in the above embodiment will be described. Specifically, a plurality of samples (Sample 1 to Sample 5) in which a metal oxynitride film was formed on a substrate by the method shown in the above embodiment were prepared, and out-of-plane measurement and φ scan using X-rays were performed on each sample. For Sample 1 and Sample 2, a metal oxynitride film was formed on the substrate, and a metal nitride film was formed on the metal oxynitride film. For Sample 3, a metal oxide film was formed on the substrate, and a metal nitride film was formed on the metal oxide film. For Sample 4 and Sample 5, a metal nitride film was formed on the substrate as a comparison target for Samples 1 to 3.

[0313] <Method for preparing samples> First, the manufacturing methods of Samples 1 to 3 will be described. Note that Samples 4 and 5 were prepared as comparison targets for Samples 1 to 3.

[0314] Samples 1 to 3 were fabricated using the method for fabricating a metal oxynitride film exemplified in Embodiment 1. Specifically, a single-crystalline substrate was prepared, and a metal oxynitride film was formed on the substrate by a sputtering method using an oxide target by introducing a gas into a reaction chamber. Note that no pretreatment such as atmospheric annealing or vacuum annealing at a high temperature was performed on the substrate before forming the metal oxynitride film thereon. Further, no heat treatment was performed on the formed metal oxynitride film.

[0315] As the film formation conditions of the metal oxynitride film common to Samples 1 to 3, the film formation pressure was 0.4 Pa, the film formation power was 200 W, and the distance between the oxide target and the substrate was 130 mm.

[0316] The single-crystalline substrate used for fabricating each sample will be described. As the single-crystalline substrate, an a-plane sapphire substrate was prepared for Sample 1. For Samples 2 and 3, a yttria-stabilized zirconia (YSZ) substrate was prepared. The plane orientation of the a-plane sapphire substrate is (110), and the plane orientation of the YSZ substrate is (111). Note that in this example, it was confirmed that the metal oxynitride film and indium tin oxide function as a buffer layer even when substrates with different plane orientations are used.

[0317] Next, the oxide target used for fabricating each sample will be described. As the oxide target, an In-Ga-Zn oxide target with an atomic ratio of In:Ga:Zn = 4:2:4.1 was used for Samples 1 and 2. Therefore, the metal oxynitride films of Samples 1 and 2 are In-Ga-Zn oxynitride films (denoted as IGZON). Further, as the oxide target, indium tin oxide was used for Sample 3.

[0318] Next, the gas introduced into the reaction chamber (also referred to as a film formation gas) will be described. As the film formation gas, 45 sccm of nitrogen gas (N2) was used for Samples 1 and 2. Further, as the film formation gas, a mixed gas of 5 sccm of oxygen gas (O2) and 40 sccm of argon gas (Ar) was used for Sample 3.

[0319] Subsequently, as the film formation conditions for the metal nitride films common to Sample 1 to Sample 3, the film formation pressure was set to 0.4 Pa, the film formation power was set to 200 W, and the distance between the nitride target and the substrate was set to 130 mm. Note that a metal oxynitride film was formed on the substrates of Sample 1 and Sample 2, and the metal oxynitride film is an In-Ga-Zn oxynitride film. Also, a metal oxide film was formed on the substrate of Sample 3, and the metal oxide film is an indium tin oxide film.

[0320] Next, the nitride targets used in the production of each sample will be described. As the nitride target, a sintered body target of GaN was used for Samples 1 to 3.

[0321] Next, the gas introduced into the reaction chamber (also referred to as the film formation gas) will be described. As the film formation gas, 45 sccm of nitrogen gas (N2) was used for Samples 1 to 3.

[0322] Note that pretreatment and heat treatment after film formation were not performed on Samples 1 to 3.

[0323] Next, the substrate temperature during the formation of the metal oxynitride film will be described. The substrate temperatures of Samples 1 to 3 were set to 200°C.

[0324] Next, the substrate temperature during the formation of the metal nitride film will be described. The substrate temperatures of Samples 1 to 3 were set to 300°C.

[0325] Thus, Samples 1 to 3 were produced. Table 1 and Table 2 show a summary of the processing conditions for each sample. Table 1 shows the processing conditions for producing the metal oxynitride film, and Table 2 shows the processing conditions for producing the metal nitride film. Note that for Sample 4, a metal nitride film was formed on an a-plane sapphire substrate, and for Sample 5, a metal nitride film was formed on a yttria-stabilized zirconia (YSZ) substrate.

[0326]

Table 1

[0327]

Table 2

[0328] For each of the prepared Samples 1 to 5, out-of-plane measurement using X-rays and φ scan were performed. As the apparatus for X-ray measurement, an X-ray diffractometer D8 DISCOVER manufactured by Bruker Japan was used, and as the detector, a 0-dimensional detector was used. In this example, the results of out-of-plane measurement and φ scan are illustrated.

[0329] In each figure showing the results of φ scan, the horizontal axis is the angle φ [°] (denoted as phi(deg.)), and the vertical axis is the peak intensity (denoted as Intensity(a.u.)). Also, in order to evaluate the in-plane orientation, the full width at half maximum of the measured peak was evaluated.

[0330] As a result of performing φ scan on each sample, in this example, six diffraction peaks were measured in each sample. Therefore, it was confirmed that the crystal structure of the metal nitride formed on the metal oxynitride in Samples 1 to 3 is the wurtzite structure.

[0331] Also, in this example, the results of out-of-plane measurement, the results of φ scan (denoted as phi scan(GaN)), and the results of φ scan of the substrate used to prepare the sample (denoted as phi scan(substrate)) are shown in Fig. 17. Also, Table 3 shows the results of measuring the full width at half maximum (FWHM) from the results of φ scan of Samples 1 to 5. Note that the explanation of the results of out-of-plane measurement and the results of φ scan of the substrate used to prepare the sample is omitted.

[0332]

Table 3

[0333] Subsequently, the evaluation results of Samples 1 to 3 will be described in detail.

[0334] <Evaluation of Sample 1> The measurement results of Sample 1 are shown in Fig. 17. Sample 1 was fabricated by depositing an In-Ga-Zn oxynitride film on an a-plane sapphire (denoted as a-plane sapphire) substrate, and then depositing a metal nitride film (GaN) on the In-Ga-Zn oxynitride film.

[0335] As a result of the φ scan of Sample 1, six diffraction peaks were observed. For comparison, Sample 4 was fabricated. Sample 4 was fabricated by depositing a metal nitride film (GaN) on an a-plane sapphire substrate. It can be seen that both Sample 1 and Sample 4 have six diffraction peaks and both have six-fold symmetry.

[0336] That is, it can be seen that the (101) plane of the metal nitride film (GaN) of Sample 1 has six-fold symmetry and the metal nitride film (GaN) of Sample 1 is in-plane oriented. Also, since the angle between the (002) plane and the (101) plane of the wurtzite structure is about 62°, it can be seen from the peaks showing six-fold symmetry obtained by performing a φ scan at this angle that the crystal of the metal nitride film (GaN) of Sample 1 has a wurtzite structure. Therefore, it can be seen that the metal nitride film (GaN) of Sample 1 is a c-axis epitaxial film.

[0337] From the above, it can be seen that the metal nitride film of Sample 1 has a wurtzite structure and is epitaxially grown. The full width at half maximum (FWHM) of the diffraction peaks of Sample 1 measured by φ scan was 5.25. Therefore, the In-Ga-Zn oxynitride film is preferable as a buffer layer for growing the metal nitride film (GaN).

[0338] <Evaluation of Sample 2> The measurement results of Sample 2 are shown in Fig. 17. Sample 2 was fabricated by depositing an In-Ga-Zn oxynitride film on a yttria-stabilized zirconia (YSZ) substrate, and then depositing a metal nitride film (GaN) on the In-Ga-Zn oxynitride film.

[0339] As a result of the φ scan of Sample 2, six diffraction peaks were observed. For comparison, Sample 5 was prepared. Sample 5 was fabricated by depositing a metal nitride film (GaN) on a yttria-stabilized zirconia (YSZ) substrate. Six diffraction peaks were confirmed for both Sample 2 and Sample 5, indicating that both have a wurtzite structure.

[0340] That is, it can be seen that the (101) plane of the metal nitride film (GaN) of Sample 2 has six-fold symmetry and the metal nitride film (GaN) of Sample 2 is in-plane oriented. Also, since the angle between the (002) plane and the (101) plane of the wurtzite structure is approximately 62°, it can be seen that the crystal of the metal nitride film (GaN) of Sample 2 has a wurtz structure from the peaks showing six-fold symmetry obtained by performing a φ scan at this angle. Therefore, it can be seen that the metal nitride film (GaN) of Sample 2 is a c-axis epitaxial film.

[0341] From the above, it can be seen that the metal nitride film of Sample 2 has a wurtzite structure and is epitaxially grown. The full width at half maximum of the diffraction peak of Sample 2 measured by φ scan was 2.96. Therefore, the In-Ga-Zn oxynitride film is preferable as a buffer layer for growing the metal nitride film (GaN).

[0342] <Evaluation of Sample 3> The measurement results of Sample 3 are shown in Fig. 17. Sample 3 was fabricated by depositing an indium tin oxide (ITO) film on a yttria-stabilized zirconia (YSZ) substrate and then depositing a metal nitride film (GaN) on the indium tin oxide (ITO) film.

[0343] As a result of the φ scan of Sample 3, six diffraction peaks were observed, indicating that it has a wurtzite structure.

[0344] That is, it can be seen that the (101) plane of the metal nitride film (GaN) of Sample 3 has six-fold symmetry and the metal nitride film (GaN) of Sample 3 is in-plane oriented. Also, since the angle between the (002) plane and the (101) plane in the wurtzite structure is about 62°, it can be seen that the crystal of the metal nitride film (GaN) of Sample 3 has a wurtzite structure from the peak showing six-fold symmetry obtained by performing a φ scan at that angle. Therefore, it can be seen that the metal nitride film (GaN) of Sample 3 is a c-axis epitaxial film.

[0345] From the above, it can be seen that the metal nitride film (GaN) of Sample 3 has a wurtzite structure and is epitaxially grown. The full width at half maximum of the diffraction peak of Sample 3 measured by φ scan was 3.36. Therefore, the In-Ga-Zn oxynitride film is preferable as a buffer layer for growing the metal nitride film (GaN).

[0346] Hall effect measurements were performed on the carrier concentrations of the metal oxynitride films and metal oxide films used in Samples 1 to 3. The evaluation results of the Hall effect measurements are shown in Table 4. As an example of a Hall effect measuring instrument, a resistivity / Hall measurement system ResiTest8310 (manufactured by Toyo Technica) can be mentioned. The resistivity / Hall measurement system ResiTest8310 can perform AC (alternating current) Hall measurements that change the direction and magnitude of the magnetic field at a constant period and detect only the Hall electromotive force that appears in the sample in synchronization therewith, and can detect the Hall electromotive force even for materials with low mobility and high resistivity.

[0347] The evaluation sample was prepared by forming a metal oxynitride film on a yttria-stabilized zirconia (YSZ) substrate using the conditions shown in Table 1. Table 3 shows the results of Hall effect measurements of the evaluation sample. As a comparison target, an indium tin oxide (ITO) film and an In-Ga-Zn oxynitride film formed on a yttria-stabilized zirconia (YSZ) substrate were measured. The indium tin oxide (ITO) film is often used as a transparent conductive film in display devices and lighting devices.

[0348]

Table 4

[0349] From the results of the Hall effect measurement, it was confirmed that the In-Ga-Zn oxynitride film functions as a conductive film equivalent to an indium tin oxide (ITO) film. Also, in Sample 2, it was confirmed that by forming a metal nitride film (GaN) on the In-Ga-Zn oxynitride film, a metal nitride film (GaN) with higher crystallinity than Sample 5 can be produced. That is, the In-Ga-Zn oxynitride film is shown to function as a buffer layer for producing a metal nitride film (GaN). Further, since the In-Ga-Zn oxynitride film has conductivity equivalent to that of indium tin oxide (ITO), it can function as an electrode of an inorganic light-emitting element.

[0350] Note that the In-Ga-Zn oxynitride film can be formed by sputtering, and further, a metal nitride film (GaN) can be produced on the In-Ga-Zn oxynitride film by a sputtering method. If it is a sputtering apparatus having a plurality of sputtering targets, the In-Ga-Zn oxynitride film and the metal nitride film (GaN) can be continuously produced. Also, the In-Ga-Zn oxynitride film and the metal nitride film (GaN) can be produced at a low temperature.

[0351] The configurations, methods, etc. shown in this embodiment can be implemented in appropriate combination with at least a part of the other embodiments described in this specification.

Explanation of Reference Numerals

[0352] :10: Substrate, 11: Substrate, 12: Functional layer, 12a: Functional layer, 12b: Functional layer, 12c: Functional layer, 13: Light-shielding layer, 14: Display section, 20: Metal oxynitride film, 20a: Crystal, 30: Metal nitride film, 30a: Crystal, 31: Clad layer, 32: Active layer, 33: Clad layer, 34: Conductor, 35: Electrode, 36: Electrode, 41: Insulator, 43: Insulator, 47: Insulator, 47a: Insulator, 48: Insulator, 49: Insulator, 51: Insulator, 52: Conductor, 54: Conductor, 54a: Magnet unit, 56: Conductor, 56a: Conductor, 56d: Conductor, 58: Terminal, 59: Conductor, 59a: Conductor, 59d: Conductor, 61: Insulator, 63: Insulator, 65: Insulator, 67: Insulator, 69: Insulator, 71: Conductor, 71a: Conductor, 71b: Conductor, 72: Conductor, 72a: Conductor, 72b: Conductor, 81: Insulator, 83: Insulator, 85: Insulator, 87: Insulator, 91: Transistor, 92: Transistor, 92A: Transistor, 92B: Transistor, 92L: Transistor formation layer, 93: Transistor, 95: Capacitor, 95L: Capacitor formation layer, 100: Inorganic light-emitting element, 100L: Inorganic light-emitting element formation layer, 101: Reciprocal lattice point, 111: Reciprocal lattice point, 200: Sputtering apparatus, 201: Film formation chamber, 202: Substrate holder, 203: Substrate, 204: Sputtering target, 205: Backing plate, 206: Magnet unit, 206a: Magnet unit, 206b: Magnet unit, 207a: Swing range, 207b: Swing range, 400: Display device, 401: Pixel section, 402: Driving circuit, 403: Driving circuit, 503: Conductor, 503a: Conductor, 503b: Conductor, 518: Conductor, 530: Oxide, 530a: Oxide, 530b: Oxide, 540a: Conductor, 540b: Conductor, 542: Conductor, 542a: Conductor, 542b: Conductor, 543a: Region, 543b: Region, 545: Insulator, 552: Insulator, 560: Conductor, 560a: Conductor, 560b: Conductor, 900: Information terminal, 901: Display panel, 902: Housing, 902a: Housing, 902b: Housing, 903: Optical member, 904: Mounting section, 905: Camera, 906: Display area, 907: Wireless communication device, 908: Integrated circuit, 909: Camera, 910: Cable, 911: Lens, 912: Reflector, 913: Reflecting surface, 915: Light, 916: Transmitted light, 5001: Display section,5002: Dashboard, 5003: Steering wheel, 5004: Windshield, 5005: Camera, 5006: Air vent, 5007: Display panel, 5007a: Display panel, 5007b: Display panel, 5007c: Display panel, 5007d: Display panel, 7000: Display unit, 7100: Television device, 7101: Housing, 7103: Stand, 7111: Remote control unit, 7200: Notebook personal computer, 7211: Housing, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Housing, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Column, 7411: Information terminal

Claims

1. A method for manufacturing a device, comprising forming a first film and a second film on a substrate, the method comprising: a first step of forming the first film by a sputtering method using an oxide target containing zinc and having electrical conductivity; a second step of forming the second film on the first film by a sputtering method using a nitride target that contains gallium and nitrogen and has conductivity.

2. In claim 1, a first gas supplying a first film to the substrate, the first gas supplying a first gas to the substrate, the first gas supplying a first gas to the substrate, the first gas supplying a first gas to the substrate, the first gas supplying a first gas to the substrate, the first gas supplying a first gas to the substrate, the first gas supplying a first gas to the substrate,

3. In claim 1 or 2, a second gas supplying a second gas to the substrate, the second gas supplying a second gas to the substrate, the second gas supplying a second gas to the substrate, the second gas supplying a second gas to the substrate, the second gas supplying a second gas to the substrate, the second gas supplying a second gas to the substrate, the second gas supplying a second gas to the substrate,

4. A first film and a second film on the first film, the first film comprises indium, zinc, oxygen, and nitrogen; the second film comprises gallium and nitrogen; the second film has a wurtzite structure; The device, wherein the first membrane functions as one of the electrodes.

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