JP2018157167A - Field-effect transistor, display element, display device, and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a field-effect transistor capable of improving reliability in electric characteristics.SOLUTION: Provided is a field-effect transistor having: a gate electrode; source and drain electrodes; a semiconductor layer; and a gate insulating layer provided between the gate electrode and the semiconductor layer. In a temperature rising desorption gas analysis method, an emission amount of carbon dioxide molecules is equal to or less than 6×10molecules/cm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a field effect transistor, a display element, a display device, and a system.

In recent years, liquid crystal displays, electronic paper, and the like have been put into practical use as flat panel displays (FPD). These FPDs are driven by a drive circuit including a field effect transistor using, for example, amorphous silicon, polycrystalline silicon or the like as a semiconductor layer. A field effect transistor using an oxide semiconductor such as zinc oxide (ZnO), In ₂ O ₃ , In—Ga—Zn—O as a semiconductor layer has also been proposed.

  By the way, it is known that when a specific component remains in the field effect transistor, the reliability of the electric characteristics of the field effect transistor is lowered. Therefore, in field effect transistors, it has been proposed to define the peak of desorbed components derived from moisture, or to define the release amount of hydrogen molecules and ammonia molecules (see, for example, Patent Documents 1 and 2). ). However, further improvement in the reliability of the electric characteristics of the field effect transistor is required.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a field effect transistor with improved reliability of electrical characteristics.

The field effect transistor is a field effect transistor having a gate electrode, a source electrode and a drain electrode, a semiconductor layer, and a gate insulating layer provided between the gate electrode and the semiconductor layer. In the temperature-programmed desorption gas analysis method, it is a requirement that the amount of carbon dioxide molecules released is 6 × 10 ²¹ molecules / cm ³ or less.

  According to the disclosed technology, a field-effect transistor with improved electrical property reliability can be provided.

1 is a cross-sectional view illustrating a field effect transistor according to a first embodiment. It is a figure which illustrates the manufacturing process of the field effect transistor which concerns on 1st Embodiment. It is sectional drawing which illustrates the field effect transistor which concerns on the modification of 1st Embodiment. It is a figure which shows the TDS analysis result of Example 1. FIG. It is a figure which shows the TDS analysis result of Example 2. It is a figure which shows the TDS analysis result of the comparative example 1. It is a figure which shows the TDS analysis result of the comparative example 2. It is a figure which shows the TDS analysis result and transistor performance evaluation result of an Example and a comparative example. It is a block diagram which shows the structure of the television apparatus which concerns on 2nd Embodiment. It is explanatory drawing (the 1) of the television apparatus which concerns on 2nd Embodiment. It is explanatory drawing (the 2) of the television apparatus which concerns on 2nd Embodiment. It is explanatory drawing (the 3) of the television apparatus which concerns on 2nd Embodiment. It is explanatory drawing of the display element which concerns on 2nd Embodiment. It is explanatory drawing of organic EL which concerns on 2nd Embodiment. Explanatory drawing of the television apparatus which concerns on 2nd Embodiment (the 4) It is explanatory drawing (the 1) of the other display element which concerns on 2nd Embodiment. It is explanatory drawing (the 2) of the other display element which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<First Embodiment>
[Structure of field effect transistor]
FIG. 1 is a cross-sectional view illustrating a field effect transistor according to the first embodiment. Referring to FIG. 1, a field effect transistor 10 includes a base 11, a semiconductor layer 12, a source electrode 13, a drain electrode 14, a gate insulating layer 15, and a gate electrode 16. This is a contact-type field effect transistor.

  In this embodiment, for convenience, the gate electrode 16 side is the upper side or one side, and the base material 11 side is the lower side or the other side. In addition, the surface on the gate electrode 16 side of each part is the upper surface or one surface, and the surface on the substrate 11 side is the lower surface or the other surface. However, the field effect transistor 10 can be used upside down, or can be arranged at an arbitrary angle. Further, the plan view refers to viewing the object from the normal direction (Z direction) of the upper surface of the substrate 11, and the planar shape refers to the object from the normal direction (Z direction) of the upper surface of the substrate 11. It shall refer to the shape as viewed. Further, a cross section cut in the stacking direction of each part on the base material 11 is a longitudinal cross section, and a cross section cut in a direction perpendicular to the stacking direction of each part on the base material 11 (a direction parallel to the upper surface of the base material 11). A cross section.

  In the field effect transistor 10, the source electrode 13 and the drain electrode 14 are formed on the semiconductor layer 12 so that the semiconductor layer 12 is formed in a predetermined region on the insulating base material 11 and a channel is formed in the semiconductor layer 12. Is formed. Further, a gate insulating layer 15 is formed so as to cover at least part of the semiconductor layer 12, the source electrode 13, and the drain electrode 14, and a gate electrode 16 is formed on the gate insulating layer 15. Hereinafter, each component of the field effect transistor 10 will be described in detail.

  The base material 11 is an insulating member on which the semiconductor layer 12 and the like are formed. There is no restriction | limiting in particular as a material of the base material 11, Although it can select suitably according to the objective, For example, a glass base material, a plastic base material, etc. can be used. There is no restriction | limiting in particular as a glass base material, Although it can select suitably according to the objective, For example, an alkali free glass, a silica glass, etc. are mentioned.

  Moreover, there is no restriction | limiting in particular as a plastic base material, Although it can select suitably according to the objective, For example, a polycarbonate (PC), a polyimide (PI), a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN) etc. Is mentioned.

  The semiconductor layer 12 is formed in a predetermined region on the base material 11. The semiconductor layer 12 located between the source electrode 13 and the drain electrode 14 becomes a channel region. There is no restriction | limiting in particular as an average film thickness of the semiconductor layer 12, Although it can select suitably according to the objective, 5 nm-1 micrometer are preferable and 10 nm-0.5 micrometer are more preferable.

  There is no restriction | limiting in particular as a material of the semiconductor layer 12, Although it can select suitably according to the objective, For example, a polycrystalline silicon (p-Si), an amorphous silicon (a-Si), an oxide semiconductor, etc. are mentioned. It is done. Among these, it is preferable to use an oxide semiconductor from the viewpoint of stability of the interface with the gate insulating layer 15.

  As the oxide semiconductor that forms the semiconductor layer 12, for example, an n-type oxide semiconductor can be used. The n-type oxide semiconductor is not particularly limited and may be appropriately selected depending on the purpose. However, at least one of indium (In), Zn, tin (Sn), and Ti, an alkaline earth element, or It preferably contains a rare earth element, and more preferably contains In and an alkaline earth element or a rare earth element.

  Examples of alkaline earth elements include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

  Examples of rare earth elements include scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), Examples include gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

Indium oxide has an electron carrier concentration of about 10 ¹⁸ cm ⁻³ to 10 ²⁰ cm ⁻³ depending on the oxygen deficiency. However, indium oxide has a property that oxygen vacancies are easily generated, and there is a case where unintended oxygen vacancies may be generated in a subsequent process after forming a semiconductor layer made of an oxide. The formation of oxides mainly from two metals, indium and alkaline earth elements and rare earth elements that are more likely to bond with oxygen than indium, prevents unintentional oxygen vacancies and facilitates control of the composition. This is particularly preferable in terms of easy control of the concentration.

  The n-type oxide semiconductor constituting the semiconductor layer 12 is a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, a hexavalent cation, a hexavalent cation, and an octavalent cation. It is preferable that substitution doping is performed with at least one of the dopants, and the valence of the dopant is larger than the valence of the metal ion (excluding the dopant) constituting the n-type oxide semiconductor. Substitution doping is also referred to as n-type doping.

  The source electrode 13 and the drain electrode 14 are formed on the base material 11. The source electrode 13 and the drain electrode 14 cover a part of the semiconductor layer 12 and are formed with a predetermined interval as a channel region. The source electrode 13 and the drain electrode 14 are electrodes for taking out a current in response to application of a gate voltage to the gate electrode 16. Note that the wiring connected to the source electrode 13 and the drain electrode 14 may be formed in the same layer together with the source electrode 13 and the drain electrode 14.

  The material for the source electrode 13 and the drain electrode 14 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, aluminum (Al), platinum (Pt), palladium (Pd), gold (Au) , Silver (Ag), Copper (Cu), Zinc (Zn), Nickel (Ni), Chromium (Cr), Tantalum (Ta), Molybdenum (Mo), Titanium (Ti), etc., alloys thereof, these metals A mixture of the above can be used. In addition, conductive oxides such as indium oxide, zinc oxide, tin oxide, gallium oxide, and niobium oxide, composite compounds thereof, mixtures thereof, and the like may be used.

  There is no restriction | limiting in particular as an average film thickness of the source electrode 13 and the drain electrode 14, Although it can select suitably according to the objective, 40 nm-2 micrometers are preferable, and 70 nm-1 micrometer are more preferable.

  The gate insulating layer 15 is formed on the substrate 11 so as to cover the semiconductor layer 12 and at least a part of the source electrode 13 and the drain electrode 14. The gate insulating layer 15 is a layer for insulating the source electrode 13 and the drain electrode 14 from the gate electrode 16. There is no restriction | limiting in particular as an average film thickness of the gate insulating layer 15, Although it can select suitably according to the objective, 50 nm-1000 nm are preferable and 100 nm-500 nm are more preferable.

  The gate insulating layer 15 is, for example, an oxide film. The oxide film contains at least an element A that is an alkaline earth metal and an element B that is at least one of gallium (Ga), scandium (Sc), yttrium (Y), and preferably a lanthanoid, , Zr (zirconium) and Hf (hafnium) are contained at least one element C, and further contains other components as required. The alkaline earth metal contained in the oxide film may be one type or two or more types.

  Lanthanoids include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium. (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

  The oxide film preferably contains a paraelectric amorphous oxide or is formed of the paraelectric amorphous oxide itself. The paraelectric amorphous oxide is stable in the atmosphere and can stably form an amorphous structure in a wide composition range. However, crystals may be included in part of the oxide film.

  Alkaline earth oxides easily react with moisture and carbon dioxide in the atmosphere and easily change to hydroxides and carbonates, and are not suitable for application to electronic devices alone. In addition, simple oxides such as lanthanoids excluding Ga, Sc, Y, and Ce are easily crystallized, and leakage current becomes a problem. However, an oxide system of an alkaline earth metal and a lanthanoid other than Ga, Sc, Y, and Ce is stable in the atmosphere and can form an amorphous film in a wide composition range. Ce is specifically tetravalent among lanthanoids and forms crystals with a perovskite structure with an alkaline earth metal. Therefore, in order to obtain an amorphous phase, lanthanoids other than Ce are preferable.

  A crystal phase such as a spinel structure exists between the alkaline earth metal and the Ga oxide, but these crystals do not precipitate unless the temperature is very high (generally 1000 ° C. or higher) as compared with the perovskite structure crystal. . In addition, the existence of a stable crystal phase has not been reported between alkaline earth metal oxides and oxides composed of lanthanoids excluding Sc, Y, and Ce. Crystal precipitation is rare. Further, when an oxide of an alkaline earth metal and a lanthanoid excluding Ga, Sc, Y, and Ce is composed of three or more kinds of metal elements, the amorphous phase is further stabilized.

  The content of each element contained in the oxide film is not particularly limited, but it is preferable that a metal element selected from each element group is contained so as to obtain a composition that can take a stable amorphous state.

  From the viewpoint of producing a high dielectric constant film, it is preferable to increase the composition ratio of elements such as Ba, Sr, Lu, and La.

Since the oxide film according to this embodiment can form an amorphous film in a wide composition range, the physical properties can also be controlled widely. For example, although the relative dielectric constant is about 6 to 20 and is sufficiently higher than that of SiO ₂ , it can be adjusted to an appropriate value according to the application by selecting the composition.

Further, the thermal expansion coefficient is equivalent to that of general wiring materials and semiconductor materials having 10 ⁻⁶ to 10 ⁻⁵ , and even if the heating process is repeated as compared with SiO ₂ having a thermal expansion coefficient of 10 ⁻⁷ units, the film There are few troubles such as peeling. In particular, a favorable interface is formed with an oxide semiconductor such as a-IGZO.

  Therefore, a high-performance semiconductor device can be obtained by using the oxide film according to this embodiment for the gate insulating layer 15.

However, the gate insulating layer 15 contains at least an A element and a B element, and is preferably not limited to an oxide film containing a C element. The gate insulating layer 15 may be, for example, an oxide film containing Si and an alkaline earth metal. The gate insulating layer 15 may be a film made of, for example, SiO ₂ , Si ₃ N ₄ , SiON, Al ₂ O ₃ or the like.

  The gate electrode 16 is formed on the gate insulating layer 15. The gate electrode 16 is an electrode for applying a gate voltage. The gate electrode 16 faces the semiconductor layer 12 with the gate insulating layer 15 interposed therebetween. Note that the gate electrode 16 and the wiring connected to the gate electrode 16 may be formed in the same layer.

  The material of the gate electrode 16 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), silver (Ag) ), Copper (Cu), zinc (Zn), nickel (Ni), chromium (Cr), tantalum (Ta), molybdenum (Mo), titanium (Ti) and other metals, alloys thereof, mixtures of these metals, etc. Can be used.

  As the material of the gate electrode 16, conductive oxides such as indium oxide, zinc oxide, tin oxide, gallium oxide, niobium oxide, a composite compound thereof, a mixture thereof, or the like may be used. Further, an organic conductor such as polyethylene dioxythiophene (PEDOT) or polyaniline (PANI) may be used. There is no restriction | limiting in particular as an average film thickness of the gate electrode 16, Although it can select suitably according to the objective, 10 nm-1 micrometer are preferable and 50 nm-300 nm are more preferable.

[Method for Manufacturing Field Effect Transistor]
Next, a method for manufacturing the field effect transistor shown in FIG. 1 will be described. FIG. 2 is a diagram illustrating a manufacturing process of the field effect transistor according to the first embodiment.

  First, in the process shown in FIG. 2A, a base material 11 made of a glass base material or the like is prepared, and a semiconductor layer 12 is formed on the base material 11. The material and thickness of the base material 11 can be appropriately selected as described above. Further, from the viewpoint of cleaning the surface of the substrate 11 and improving adhesion, it is preferable to perform a pretreatment such as oxygen plasma, UV ozone, UV irradiation cleaning.

  A method for forming the semiconductor layer 12 is not particularly limited and may be appropriately selected depending on the purpose. For example, a sputtering method, a pulse laser deposition (PLD) method, a chemical vapor deposition (CVD) method, an atom Examples include a method of patterning by photolithography and etching after film formation by a vacuum process such as layer deposition (ALD) or a solution process such as dip coating, spin coating, or die coating. The material and thickness of the semiconductor layer 12 can be appropriately selected as described above.

  Next, in the step shown in FIG. 2B, the source electrode 13 and the drain electrode 14 are formed on the semiconductor layer 12. There is no restriction | limiting in particular as a method of forming the source electrode 13 and the drain electrode 14, According to the objective, it can select suitably, For example, a sputtering method, a vacuum evaporation method, a dip coating method, a spin coat method, a die coat method etc. There is a method of patterning by photolithography and etching after the film formation. The material and thickness of the source electrode 13 and the drain electrode 14 can be appropriately selected as described above.

  Next, in the step illustrated in FIG. 2C, the gate insulating layer 15 that covers the semiconductor layer 12, the source electrode 13, and the drain electrode 14 is formed on the base material 11. There is no restriction | limiting in particular as a method of forming the gate insulating layer 15, According to the objective, it can select suitably, For example, a sputtering method, a pulse laser deposition (PLD) method, a chemical vapor deposition (CVD) method, Examples include a method of patterning by photolithography and etching after film formation by a solution process such as a vacuum process such as an atomic layer deposition (ALD) method, a dip coating method, a spin coating method, or a die coating method. The material and thickness of the gate insulating layer 15 can be appropriately selected as described above.

As an example, the case where the gate insulating layer 15 is formed from an oxide film containing an alkaline earth metal and a rare earth element will be described. In this case, by preparing a coating liquid (coating liquid for forming the gate insulating layer 15) containing the precursor of the oxide film, applying or printing it on the object to be coated, and firing it under appropriate conditions A film can be formed. This method will be described in detail below.
--- Coating liquid for forming gate insulating layer 15-
The coating liquid for forming the gate insulating layer 15 contains at least an alkaline earth metal-containing compound (A-element-containing compound), a B-element-containing compound, and a solvent, and preferably at least any of the C-element-containing compounds. In addition, other components are contained as necessary.

--- Alkaline earth metal-containing compound (element A-containing compound) ---
Examples of the alkaline earth metal-containing compound include inorganic alkaline earth metal compounds and organic alkaline earth metal compounds.

  Examples of the inorganic alkaline earth metal compound include alkaline earth metal nitrates, alkaline earth metal sulfates, alkaline earth metal chlorides, alkaline earth metal fluorides, alkaline earth metal bromides, alkaline earth metal salts, and the like. And the like.

  The organic alkaline earth metal compound is not particularly limited as long as it is a compound having an alkaline earth metal and an organic group, and can be appropriately selected according to the purpose. The alkaline earth metal and the organic group are bonded by, for example, an ionic bond, a covalent bond, or a coordinate bond.

  The organic group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. And an acyloxy group which may have a substituent, an acetylacetonate group which may have a substituent, a cyclopentadienyl group which may have a substituent, and the like. As said alkyl group, a C1-C6 alkyl group etc. are mentioned, for example. As said alkoxy group, a C1-C6 alkoxy group etc. are mentioned, for example. As said acyloxy group, a C1-C10 acyloxy group etc. are mentioned, for example.

--- B element-containing compound ---
Examples of the B element-containing compound include inorganic B element compounds and organic B element compounds.

  Examples of the inorganic B element compound include nitrate of B element, sulfate of B element, fluoride of B element, chloride of B element, bromide of B element, iodide of B element Etc.

  The organic B element compound is not particularly limited as long as it is a compound having the B element and an organic group, and can be appropriately selected according to the purpose. The element B and the organic group are bonded by, for example, an ionic bond, a covalent bond, or a coordinate bond.

  The organic group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. And an acyloxy group which may have a substituent, an acetylacetonate group which may have a substituent, a cyclopentadienyl group which may have a substituent, and the like. As said alkyl group, a C1-C6 alkyl group etc. are mentioned, for example. As said alkoxy group, a C1-C6 alkoxy group etc. are mentioned, for example. As said acyloxy group, a C1-C10 acyloxy group etc. are mentioned, for example.

--- Element C-containing compound ---
Examples of the C element-containing compound include an inorganic compound of the C element and an organic compound of the C element.

Examples of the inorganic compound of the C element include nitrate of the C element, sulfate of the C element, fluoride of the C element, chloride of the C element, bromide of the C element, iodine of the C element. And the like.

  The organic compound of the C element is not particularly limited as long as it is a compound having the C element and an organic group, and can be appropriately selected according to the purpose. The C element and the organic group are bonded by, for example, an ionic bond, a covalent bond, or a coordinate bond.

  The organic group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. And an acyloxy group which may have a substituent, an acetylacetonate group which may have a substituent, a cyclopentadienyl group which may have a substituent, and the like. As said alkyl group, a C1-C6 alkyl group etc. are mentioned, for example. As said alkoxy group, a C1-C6 alkoxy group etc. are mentioned, for example. As said acyloxy group, a C1-C10 acyloxy group etc. are mentioned, for example.

--- Solvent ---
The solvent is not particularly limited as long as it is a solvent that can stably dissolve or disperse the various compounds, and can be appropriately selected according to the purpose. For example, toluene, xylene, mesitylene, cymene, pentylbenzene, dodecylbenzene , Bicyclohexyl, cyclohexylbenzene, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, tetralin, decalin, isopropanol, ethyl benzoate, N, N-dimethylformamide, propylene carbonate, 2-ethylhexanoic acid, mineral spirits, dimethylpropylene Examples include urea, 4-butyrolactone, 2-methoxyethanol, and water.

  There is no restriction | limiting in particular as content of the solvent in the coating liquid for gate insulating layer 15 formation, According to the objective, it can select suitably.

--- Method of forming gate insulating layer 15 ---
An example of a method for forming the gate insulating layer 15 using the coating liquid for forming the gate insulating layer 15 will be described. The method for forming the gate insulating layer 15 includes a coating process and a heat treatment process, and further includes other processes as necessary.

  The application step is not particularly limited as long as it is a step of applying a coating liquid for forming the gate insulating layer 15 to an object to be coated, and can be appropriately selected according to the purpose. The application method is not particularly limited and can be appropriately selected depending on the purpose. For example, a desired method can be selected by a method of patterning by photolithography after film formation by a solution process, a printing method such as inkjet, nanoimprint, or gravure. And a method of directly forming the film shape. Examples of the solution process include dip coating, spin coating, die coating, and nozzle printing.

  The heat treatment step is not particularly limited as long as it is a step of heat-treating the coating liquid for forming the gate insulating layer 15 applied to the object to be coated, and can be appropriately selected according to the purpose. Note that when the heat treatment is performed, the coating liquid for forming the gate insulating layer 15 applied to the object to be coated may be dried by natural drying or the like. By the heat treatment, drying of the solvent, generation of the first oxide, and the like are performed.

  In the heat treatment step, it is preferable that the solvent is dried (hereinafter referred to as “drying process”) and the paraelectric amorphous oxide is formed (hereinafter referred to as “generation process”) at different temperatures. That is, it is preferable to generate a paraelectric amorphous oxide by raising the temperature after drying the solvent. When the paraelectric amorphous oxide is generated, for example, decomposition of at least one of an alkaline earth metal-containing compound (A-element-containing compound), a B-element-containing compound, and a C-element-containing compound occurs.

  There is no restriction | limiting in particular as temperature of a drying process, According to the solvent to contain, it can select suitably, For example, 80 to 180 degreeC is mentioned. In drying, it is effective to use a vacuum oven or the like for lowering the temperature. There is no restriction | limiting in particular as time of a drying process, According to the objective, it can select suitably, For example, 1 minute-1 hour are mentioned.

  There is no restriction | limiting in particular as temperature of a production | generation process, Although it can select suitably according to the objective, 100 degreeC or more and less than 550 degreeC are preferable, and 200 to 500 degreeC is more preferable. There is no restriction | limiting in particular as time of a production | generation process, According to the objective, it can select suitably, For example, 1 hour-5 hours are mentioned.

  In the heat treatment step, the drying process and the generation process may be performed continuously, or may be divided into a plurality of processes.

  There is no restriction | limiting in particular as the method of heat processing, According to the objective, it can select suitably, For example, the method etc. which heat a to-be-coated article are mentioned. There is no restriction | limiting in particular as atmosphere in heat processing, Although it can select suitably according to the objective, Oxygen atmosphere is preferable. By performing the heat treatment in an oxygen atmosphere, the decomposition product can be quickly discharged out of the system, and the generation of the first oxide can be promoted.

  In the heat treatment, it is effective to irradiate the material after the drying treatment with ultraviolet light having a wavelength of 400 nm or less in order to accelerate the reaction of the generation treatment.

  By irradiating ultraviolet light with a wavelength of 400 nm or less, chemical bonds such as organic substances contained in the material after drying treatment can be broken and the organic substances can be decomposed, so that a paraelectric amorphous oxide can be efficiently formed. Can do.

  The ultraviolet light having a wavelength of 400 nm or less is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ultraviolet light having a wavelength of 222 nm using an excimer lamp. It is also preferable to apply ozone in place of or in combination with ultraviolet light irradiation. By applying ozone to the substance after the drying treatment, generation of oxide is promoted.

  Next, in the step shown in FIG. 2D, the gate electrode 16 is formed on the gate insulating layer 15. The method for forming the gate electrode 16 is not particularly limited and may be appropriately selected depending on the purpose. For example, sputtering, pulse laser deposition (PLD), chemical vapor deposition (CVD), atomic Examples include a method of patterning by photolithography and etching after film formation by a solution process such as a vacuum process such as a layer deposition (ALD) method, a dip coating method, a spin coating method, or a die coating method. The material and thickness of the gate electrode 16 can be appropriately selected as described above.

  Through the above steps, the top gate / top contact field effect transistor 10 shown in FIG. 1 can be manufactured.

  The field effect transistor 10 preferably does not contain an organic component (carbon). For example, if an organic component remains in the semiconductor layer 12, formation of a dense film is hindered, which may cause a decrease in on-current. In addition, when an organic component remains in the gate insulating layer 15, formation of a dense film is hindered, which may cause a decrease in insulating performance (an increase in leakage current and a decrease in breakdown voltage), a threshold voltage variation of the transistor, and the like.

  However, an organic component may remain in the field effect transistor 10. There are various reasons why the organic component remains in the field effect transistor 10. For example, when the semiconductor layer 12 or the gate insulating layer 15 is formed by a solution process (coating method), the semiconductor layer 12 or the gate insulating layer 15 is formed. The constituent metals and oxides are dissolved and dispersed in the coating solution as organometallic compounds.

  An organic solvent is mainly used as a solvent for the coating solution. These organometallic compounds and organic solvents often contain carbon. A coating solution is applied by a coating method, and an oxide film to be the semiconductor layer 12 and the gate insulating layer 15 is formed through drying and baking. In this step, most of the organic components are released out of the system, but some may remain in the semiconductor layer 12 and the gate insulating layer 15.

  As described above, it is preferable that no organic component remains in the semiconductor layer 12 or the gate insulating layer 15, but it is preferable to define the remaining amount of the organic component because there is a possibility that the organic component may remain. In the present embodiment, the reliability of the electrical characteristics is ensured by setting the amount of the organic component remaining in the field effect transistor to a predetermined value or less.

Specifically, in the field effect transistor 10, the temperature desorption gas analysis (TDS analysis: Thermal Desorption Spectroscopy analysis) sets the emission amount of carbon dioxide molecules to 6 × 10 ²¹ molecules / cm ³ or less.

  In TDS analysis, a sample is heated in a high vacuum, and molecules (carbon dioxide, hydrogen, water, oxygen, etc.) desorbed from the sample (in each layer constituting the sample) by heating are subjected to quadrupole mass spectrometry. This is a method of detecting with a meter (Q-MS: Quadrupole Mass Spectrometer).

  Specifically, for example, for the field-effect transistor 10 that is the obtained sample, the base material 11 is divided into a desired shape, and a temperature programmed desorption analyzer (for example, TDS1200II, manufactured by Electronic Science Co., Ltd.) is used. TDS analysis can be performed. At this time, it is preferable to heat the sample temperature at 50 ° C. or more and 500 ° C. or less.

By defining the emission amount of carbon dioxide molecules from the entire field effect transistor 10 to 6 × 10 ²¹ molecules / cm ³ or less, the residual amount of organic components in the semiconductor layer 12 and the gate insulating layer 15 also becomes a predetermined value or less. . Therefore, the residual amount of the organic component in the semiconductor layer 12 may increase, leading to a decrease in on-current, or the residual amount of the organic component in the gate insulating layer 15 may increase, resulting in a decrease in insulation performance and fluctuations in the threshold voltage of the transistor. Etc. can be reduced.

  In the field effect transistor 10, the amount of organic components remaining in the entire field effect transistor is suppressed to a predetermined value or less by adjusting the manufacturing process.

  For example, when the semiconductor layer 12 or the gate insulating layer 15 is manufactured by a solution process, by adjusting the baking conditions (for example, baking atmosphere, baking temperature, baking time, etc.) of the semiconductor layer 12 and the gate insulating layer 15, The residual amount of organic components in the semiconductor layer 12 and the gate insulating layer 15 (that is, the amount of released carbon dioxide molecules detected by TDS analysis) can be suppressed to a predetermined value or less.

The adjustment of the firing conditions of the semiconductor layer 12 and the gate insulating layer 15 is an example of a technique for suppressing the residual amount of organic components in the semiconductor layer 12 and the gate insulating layer 15, and is not limited to this. In short, the inventor said that the reliability of the electrical characteristics of the field-effect transistor 10 is improved by setting the emission amount of carbon dioxide molecules in the TDS analysis of the field-effect transistor 10 to 6 × 10 ²¹ molecules / cm ³ or less. Knowledge is important, and any specific manufacturing process to achieve this is irrelevant.

<Modification of First Embodiment>
The modification of the first embodiment shows an example of a field effect transistor having a layer structure different from that of the first embodiment. In the modification of the first embodiment, the description of the same components as those of the already described embodiments may be omitted.

  FIG. 3 is a cross-sectional view illustrating a field effect transistor according to a modification of the first embodiment.

  A field effect transistor 10A shown in FIG. 3A is a top gate / bottom contact field effect transistor. A field effect transistor 10B shown in FIG. 3B is a bottom gate / top contact field effect transistor. A field effect transistor 10C shown in FIG. 3C is a bottom gate / bottom contact field effect transistor. The field effect transistors 10A, 10B, and 10C are typical examples of the semiconductor device according to the present invention.

In the field effect transistors 10A, 10B, and 10C, similarly to the field effect transistor 10, the emission amount of carbon dioxide molecules is set to 6 × 10 ²¹ molecules / cm ³ or less in the TDS analysis method. Therefore, the residual amount of the organic component in the semiconductor layer 12 may increase, leading to a decrease in on-current, or the residual amount of the organic component in the gate insulating layer 15 may increase, resulting in a decrease in insulation performance and fluctuations in the threshold voltage of the transistor. Etc. can be reduced. As a result, a field effect transistor with improved electrical property reliability can be realized.

<Example 1>
In Example 1, the top gate type field effect transistor shown in FIG. 1 was manufactured by the manufacturing process shown in FIG.

-Fabrication of semiconductor layer 12-
First, an In—Mg-based oxide thin film to be the semiconductor layer 12 was formed on the substrate 11 made of glass by a high-frequency sputtering method. Specifically, a polycrystalline fired body having a composition of In ₂ MgO ₄ was used as the target. The ultimate vacuum in the sputtering chamber was 2 × 10 ⁻⁵ Pa. The flow rates of argon gas and oxygen gas flowing during sputtering were adjusted, and the total pressure was 0.3 Pa. By adjusting the oxygen flow rate ratio, the amount of oxygen in the oxide semiconductor film was controlled, and the electron carrier concentration was controlled. The thickness of the obtained oxide semiconductor film (semiconductor layer) was 50 nm. Next, the oxide semiconductor film was etched into a desired shape using a photolithography method.

-Production of source electrode 13 and drain electrode 14-
Next, an Au film having a thickness of 100 nm was formed as a source electrode 13 and a drain electrode 14 on the base material 11 including the semiconductor layer 12 by a vacuum deposition method. Au was used as the evaporation source. Next, the Au film was etched into a desired shape by using a photolithography method to form a channel region having a channel width of 30 μm and a channel length of 10 μm.

-Production of gate insulating layer 15-
Next, the gate insulating layer 15 was formed on the base material 11 including the semiconductor layer 12, the source electrode 13, and the drain electrode 14. Specifically, lanthanum toluene solution of ethyl 2-ethylhexanoate (La content 7%, Wako 122-03371, manufactured by Wako Chemical Co., Ltd.) 1.95 mL of cyclohexylbenzene and strontium 2-ethylhexanoate toluene solution (Sr content 2%, Wako 195-09561, manufactured by Wako Chemical Co., Ltd.) 0.57 mL, 2-ethylhexanoic acid zirconium oxide mineral spirit solution (Zr content 12%, Wako 269-01116, manufactured by Wako Chemical Co., Ltd.) 0 0.09 mL was mixed to prepare a gate insulating layer precursor coating solution.

  And the produced gate insulating layer precursor coating liquid was dripped on the base material 11, and it spin-coated on the predetermined conditions. The substrate 11 after spin coating was heated in an oven at 120 ° C. for 1 hour to form a gate insulating layer precursor. Next, the gate insulating layer precursor was converted into a gate insulating layer by heating the base material 11 at 360 ° C. for 3 hours in an oxygen atmosphere, thereby forming the gate insulating layer 15 (baking process of the gate insulating layer). The average thickness of the gate insulating layer 15 was 170 nm. Next, the gate insulating layer 15 was etched into a desired shape by using a photolithography method.

-Fabrication of gate electrode 16-
Next, an Al alloy film having a thickness of 100 nm was formed on the base material 11 including the semiconductor layer 12, the source electrode 13, the drain electrode 14, and the gate insulating layer 15 by sputtering. Next, the Al alloy film was etched into a desired shape by a photolithography method to form a gate electrode 16. In this way, a top gate / top contact field effect transistor 10 was fabricated.

-Temperature desorption gas analysis-
Next, for the obtained field effect transistor 10, the base material 11 is divided into a desired shape and heated so that the sample temperature is 50 ° C. or higher and 500 ° C. or lower. TDS analysis was performed using TDS1200II). The results are shown in FIG. FIG. 4 is a graph showing the amount of gas and carbon dioxide released with M / z = 44. The number of carbon dioxide molecules calculated from the integrated value of the graph was 6.0 × 10 ²¹ molecules / cm ³ .

-Transistor performance evaluation-
About the obtained field effect transistor 10, transistor performance evaluation was implemented using the semiconductor parameter analyzer apparatus (Agilent Technology company make, semiconductor parameter analyzer B1500A). The current / voltage characteristics (transfer characteristics) were evaluated by changing the source / drain voltage Vds to 10 V and changing the gate voltage from Vg = −15 V to +15 V. When the gate current when Vg = −15 V was extracted, it was 8.9 × 10 ⁻¹⁵ A.

<Example 2>
A field effect transistor was fabricated in the same manner as in Example 1 except that the gate insulating layer 15 was formed by baking the gate insulating layer in Example 1 at 400 ° C. for 3 hours in an oxygen atmosphere.

-Temperature desorption gas analysis-
Next, the obtained field effect transistor was subjected to TDS analysis in the same manner as in Example 1. The results are shown in FIG. FIG. 5 is a graph showing the amount of gas and carbon dioxide released with M / z = 44. The number of carbon dioxide molecules calculated from the integrated value of the graph was 4.3 × 10 ²¹ molecules / cm ³ .

-Transistor performance evaluation-
The obtained field effect transistor was evaluated for transistor performance in the same manner as in Example 1. The current / voltage characteristics (transfer characteristics) were evaluated by changing the source / drain voltage Vds to 10 V and changing the gate voltage from Vg = −15 V to +15 V. When extracting the gate current when Vg = −15 V, it was 6.0 × 10 ⁻¹⁵ A.

<Comparative example 1>
A field effect transistor was fabricated in the same manner as in Example 1 except that the gate insulating layer 15 was formed by firing the gate insulating layer in Example 1 at 360 ° C. for 1 hour in the atmosphere.

-Temperature desorption gas analysis-
Next, the obtained field effect transistor was subjected to TDS analysis in the same manner as in Example 1. The results are shown in FIG. FIG. 6 is a graph showing the amount of gas and carbon dioxide released with M / z = 44. The number of carbon dioxide molecules calculated from the integrated value of the graph was 7.8 × 10 ²¹ molecules / cm ³ .

-Transistor performance evaluation-
The obtained field effect transistor was evaluated for transistor performance in the same manner as in Example 1. The current / voltage characteristics (transfer characteristics) were evaluated by changing the source / drain voltage Vds to 10 V and changing the gate voltage from Vg = −15 V to +15 V. When the gate current when Vg = −15 V was extracted, it was 1.3 × 10 ⁻¹³ A.

<Comparative example 2>
A field effect transistor was fabricated in the same manner as in Example 1 except that the gate insulating layer 15 was formed by baking the gate insulating layer in Example 1 at 340 ° C. for 3 hours in an oxygen atmosphere.

-Temperature desorption gas analysis-
Next, the obtained field effect transistor was subjected to TDS analysis in the same manner as in Example 1. The results are shown in FIG. FIG. 7 is a graph showing the amount of gas and carbon dioxide released with M / z = 44. The number of carbon dioxide molecules calculated from the integrated value of the graph was 9.6 × 10 ²¹ molecules / cm ³ .

-Transistor performance evaluation-
The obtained field effect transistor was evaluated for transistor performance in the same manner as in Example 1. The current / voltage characteristics (transfer characteristics) were evaluated by changing the source / drain voltage Vds to 10 V and changing the gate voltage from Vg = −15 V to +15 V. When the gate current at the time of Vg = -15V was extracted, it was 2.4 × 10 ⁻¹³ A.

実施例１及び２、並びに比較例１及び２のＴＤＳ分析結果及びトランジスタ性能評価結果を表１及び図８に示した。表１及び図８より、実施例１及び２で作製した電界効果型トランジスタは、ＴＤＳ分析により算出される二酸化炭素分子数が６．０×１０^２１分子／ｃｍ^３以下であり、電界効果型トランジスタに残留する炭素数が少ない。

The TDS analysis results and transistor performance evaluation results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 and FIG. From Table 1 and FIG. 8, the field effect transistors produced in Examples 1 and 2 have a carbon dioxide molecule number calculated by TDS analysis of 6.0 × 10 ²¹ molecules / cm ³ or less, and the field effect transistors The carbon number remaining in

Therefore, mainly, a dense film made of a metal oxide is formed in the gate insulating layer, and leakage current flowing in the gate insulating layer can be suppressed to a low level. Specifically, in Example 1, the gate leakage current is 8.9 × 10 ⁻¹⁵ A, and in Example 2, the gate leakage current is 6.0 × 10 ⁻¹⁵ A. Thus, a field effect transistor with improved electrical property reliability can be realized.

On the other hand, the field effect transistor manufactured in Comparative Example 1 has a gate leakage current of 1.3 × 10 ⁻¹³ A, which is higher than those in Examples 1 and 2. In this field effect transistor, the number of carbon dioxide molecules calculated by TDS analysis is 7.8 × 10 ²¹ molecules / cm ³ , which is larger than those in Examples 1 and 2.

  In the field effect transistor fabricated in Comparative Example 1, the formation of a dense film by the metal oxide was hindered mainly because a large amount of carbon derived from the gate insulating layer precursor coating solution remained in the gate insulating layer. It is considered that the leakage current flowing in the gate insulating layer is increased. In the field effect transistor fabricated in Comparative Example 1, the gate leakage current is not kept low, so the reliability of the electrical characteristics is lowered.

Similarly, in the field effect transistor manufactured in Comparative Example 2, the gate leakage current is 2.4 × 10 ⁻¹³ A, which is higher than those in Examples 1 and 2. In this field effect transistor, the number of carbon dioxide molecules calculated by TDS analysis is 9.6 × 10 ²¹ molecules / cm ³ , which is larger than those in Examples 1 and 2.

  In the field effect transistor fabricated in Comparative Example 2, as with the field effect transistor fabricated in Comparative Example 1, a large amount of carbon derived mainly from the gate insulating layer precursor coating solution remained in the gate insulating layer. It is considered that the formation of a dense film by the metal oxide was hindered and the leakage current flowing in the gate insulating layer was increased. In the field effect transistor manufactured in Comparative Example 2, the reliability of the electrical characteristics is lowered because the gate leakage current is not kept low.

Thus, by adjusting the manufacturing process of the field effect transistor, the amount of carbon dioxide molecules emitted from the entire field effect transistor 10 can be reduced to 6 × 10 ²¹ molecules / cm ³ or less. As a result, an effect such as a reduction in gate leakage current can be obtained, and a field effect transistor with improved electrical characteristics can be realized.

<Second Embodiment>
In the second embodiment, an example of a display element, a display device, and a system using the field effect transistor according to the first embodiment is shown. In the second embodiment, description of the same components as those of the already described embodiments may be omitted.

(Display element)
The display element according to the second embodiment includes at least a light control element and a drive circuit that drives the light control element, and further includes other members as necessary. The light control element is not particularly limited as long as it is an element that controls the light output according to the drive signal, and can be appropriately selected according to the purpose. For example, an electroluminescence (EL) element, an electrochromic (EC) ) Elements, liquid crystal elements, electrophoretic elements, electrowetting elements and the like.

  The drive circuit is not particularly limited as long as it has the field effect transistor according to the first embodiment, and can be appropriately selected according to the purpose. There is no restriction | limiting in particular as another member, According to the objective, it can select suitably.

  The display element according to the second embodiment includes the field effect transistor according to the first embodiment in which reliability of electrical characteristics is improved by an effect such as reduction of gate leakage current. Therefore, a highly reliable display device with high quality can be realized.

(Display device)
The display device according to the second embodiment includes at least a plurality of display elements according to the second embodiment, a plurality of wirings, and a display control device, and other members as necessary. Have The plurality of display elements are not particularly limited as long as they are the display elements according to the plurality of second embodiments arranged in a matrix, and can be appropriately selected according to the purpose.

  The plurality of wirings are not particularly limited and can be appropriately selected depending on the purpose as long as the gate voltage and the image data signal can be individually applied to each field effect transistor in the plurality of display elements.

  The display control device is not particularly limited as long as the gate voltage and signal voltage of each field effect transistor can be individually controlled via a plurality of wirings according to image data, and is appropriately selected according to the purpose. can do. There is no restriction | limiting in particular as another member, According to the objective, it can select suitably.

  Since the display device according to the second embodiment includes the display element including the field effect transistor according to the first embodiment, it is possible to display a high-quality image.

(system)
The system according to the second embodiment includes at least a display device according to the second embodiment and an image data creation device. The image data creation device creates image data based on the image information to be displayed, and outputs the image data to the display device.

  Since the system includes the display device according to the second embodiment, the image information can be displayed with high definition.

  The display element, display device, and system according to the second embodiment will be specifically described below.

  FIG. 9 shows a schematic configuration of a television apparatus 500 as a system according to the second embodiment. In addition, the connection line in FIG. 9 shows the flow of a typical signal and information, and does not show all the connection relations of each block.

  A television apparatus 500 according to the second embodiment includes a main controller 501, a tuner 503, an AD converter (ADC) 504, a demodulation circuit 505, a TS (Transport Stream) decoder 506, an audio decoder 511, and a DA converter (DAC). 512, an audio output circuit 513, a speaker 514, a video decoder 521, a video / OSD synthesis circuit 522, a video output circuit 523, a display device 524, an OSD drawing circuit 525, a memory 531, an operation device 532, a drive interface (drive IF) 541, A hard disk device 542, an optical disk device 543, an IR light receiver 551, a communication control device 552, and the like are provided.

  The main control device 501 controls the entire television device 500 and includes a CPU, a flash ROM, a RAM, and the like. The flash ROM stores a program written in a code readable by the CPU, various data used for processing by the CPU, and the like. The RAM is a working memory.

  The tuner 503 selects a preset channel broadcast from the broadcast waves received by the antenna 610. The ADC 504 converts the output signal (analog information) of the tuner 503 into digital information. The demodulation circuit 505 demodulates the digital information from the ADC 504.

  The TS decoder 506 performs TS decoding on the output signal of the demodulation circuit 505 and separates audio information and video information. The audio decoder 511 decodes the audio information from the TS decoder 506. The DA converter (DAC) 512 converts the output signal of the audio decoder 511 into an analog signal.

  The audio output circuit 513 outputs the output signal of the DA converter (DAC) 512 to the speaker 514. The video decoder 521 decodes the video information from the TS decoder 506. The video / OSD synthesis circuit 522 synthesizes the output signal of the video decoder 521 and the output signal of the OSD drawing circuit 525.

  The video output circuit 523 outputs the output signal of the video / OSD synthesis circuit 522 to the display device 524. The OSD drawing circuit 525 includes a character generator for displaying characters and figures on the screen of the display device 524, and generates a signal including display information in response to an instruction from the operation device 532 or the IR light receiver 551. To do.

  The memory 531 temporarily stores AV (Audio-Visual) data and the like. The operating device 532 includes an input medium (not shown) such as a control panel, for example, and notifies the main controller 501 of various information input by the user. The drive IF 541 is a bi-directional communication interface, and is compliant with ATAPI (AT Attachment Packet Interface) as an example.

  The hard disk device 542 includes a hard disk and a drive device for driving the hard disk. The drive device records data on the hard disk and reproduces data recorded on the hard disk. The optical disk device 543 records data on an optical disk (for example, DVD) and reproduces data recorded on the optical disk.

  The IR light receiver 551 receives the optical signal from the remote control transmitter 620 and notifies the main controller 501 of it. The communication control device 552 controls communication with the Internet. Various information can be acquired via the Internet.

  As an example, the display device 524 includes a display 700 and a display control device 780, as shown in FIG. As shown in FIG. 11 as an example, the display 700 includes a display 710 in which a plurality of (here, n × m) display elements 702 are arranged in a matrix.

  In addition, as shown in FIG. 12 as an example, the display 710 includes n scanning lines (X0, X1, X2, X3,..., Xn) arranged at equal intervals along the X-axis direction. -2, Xn-1), m data lines (Y0, Y1, Y2, Y3, ..., Ym-1) arranged at equal intervals along the Y-axis direction, in the Y-axis direction M current supply lines (Y0i, Y1i, Y2i, Y3i,..., Ym-1i) arranged at equal intervals along the line. The display element 702 can be specified by the scan line and the data line.

  As shown in FIG. 13 as an example, each display element 702 includes an organic EL (electroluminescence) element 750 and a drive circuit 720 for causing the organic EL element 750 to emit light. That is, the display 710 is a so-called active matrix type organic EL display. The display 710 is a color-compatible 32-inch display. The size is not limited to this.

  As shown in FIG. 14 as an example, the organic EL element 750 includes an organic EL thin film layer 740, a cathode 712, and an anode 714.

The organic EL element 750 can be disposed beside a field effect transistor, for example. In this case, the organic EL element 750 and the field effect transistor can be formed on the same substrate. However, it is not limited to this, For example, the organic EL element 750 may be arrange | positioned on a field effect transistor. In this case, since transparency is required for the gate electrode, ITO, In ₂ O ₃ , SnO ₂ , ZnO, ZnO to which Ga is added, ZnO to which Al is added, and Sb are added to the gate electrode. A transparent oxide having conductivity such as SnO ₂ is used.

In the organic EL element 750, aluminum (Al) is used for the cathode 712. A magnesium (Mg) -silver (Ag) alloy, an aluminum (Al) -lithium (Li) alloy, ITO (Indium Tin Oxide), or the like may be used. ITO is used for the anode 714. Note that a conductive oxide such as In ₂ O ₃ , SnO ₂ , or ZnO, a silver (Ag) -neodymium (Nd) alloy, or the like may be used.

  The organic EL thin film layer 740 includes an electron transport layer 742, a light emitting layer 744, and a hole transport layer 746. A cathode 712 is connected to the electron transport layer 742, and an anode 714 is connected to the hole transport layer 746. When a predetermined voltage is applied between the anode 714 and the cathode 712, the light emitting layer 744 emits light.

  As shown in FIG. 13, the drive circuit 720 includes two field effect transistors 810 and 820 and a capacitor 830. The field effect transistor 810 operates as a switch element. The gate electrode G is connected to a predetermined scanning line, and the source electrode S is connected to a predetermined data line. The drain electrode D is connected to one terminal of the capacitor 830.

  The capacitor 830 is for storing the state of the field effect transistor 810, that is, data. The other terminal of the capacitor 830 is connected to a predetermined current supply line.

  The field effect transistor 820 is for supplying a large current to the organic EL element 750. The gate electrode G is connected to the drain electrode D of the field effect transistor 810. The drain electrode D is connected to the anode 714 of the organic EL element 750, and the source electrode S is connected to a predetermined current supply line.

  Therefore, when the field effect transistor 810 is turned on, the organic EL element 750 is driven by the field effect transistor 820.

  As an example, the display control device 780 includes an image data processing circuit 782, a scanning line driving circuit 784, and a data line driving circuit 786, as shown in FIG.

  The image data processing circuit 782 determines the brightness of the plurality of display elements 702 in the display 710 based on the output signal of the video output circuit 523. The scanning line driving circuit 784 individually applies voltages to the n scanning lines in accordance with an instruction from the image data processing circuit 782. The data line driving circuit 786 individually applies voltages to the m data lines in accordance with an instruction from the image data processing circuit 782.

  As is clear from the above description, in the television apparatus 500 according to the present embodiment, the video decoder 521, the video / OSD synthesis circuit 522, the video output circuit 523, and the OSD drawing circuit 525 constitute an image data creation apparatus. ing.

  In the above description, the light control element is an organic EL element. However, the present invention is not limited to this, and a liquid crystal element, an electrochromic element, an electrophoretic element, or an electrowetting element may be used.

  For example, when the light control element is a liquid crystal element, a liquid crystal display is used as the display 710. In this case, as shown in FIG. 16, the current supply line in the display element 703 is not necessary.

  In this case, as shown in FIG. 17 as an example, the drive circuit 730 is configured by only one field effect transistor 840 similar to the field effect transistor (810, 820) shown in FIG. Can do. In the field effect transistor 840, the gate electrode G is connected to a predetermined scanning line, and the source electrode S is connected to a predetermined data line. The drain electrode D is connected to the pixel electrode of the liquid crystal element 770 and the capacitor 760. Note that reference numerals 762 and 772 in FIG. 17 denote counter electrodes (common electrodes) of the capacitor 760 and the liquid crystal element 770, respectively.

  Further, the drive circuit may include a field effect transistor according to a modification of the first embodiment, instead of the field effect transistor according to the first embodiment.

  In the above embodiment, the case where the system is a television apparatus has been described. However, the present invention is not limited to this. In short, the display device 524 may be provided as a device for displaying images and information. For example, a computer system in which a computer (including a personal computer) and a display device 524 are connected may be used.

  In addition, the display device 524 is used as a display unit in a portable information device such as a mobile phone, a portable music player, a portable video player, an electronic BOOK, a PDA (Personal Digital Assistant), or an imaging device such as a still camera or a video camera. be able to. Further, the display device 524 can be used as a display unit for various information in a mobile system such as a car, an aircraft, a train, and a ship. Further, the display device 524 can be used as a display unit for various information in a measurement device, an analysis device, a medical device, and an advertising medium.

  The preferred embodiments and the like have been described in detail above, but the present invention is not limited to the above-described embodiments and the like, and various modifications can be made to the above-described embodiments and the like without departing from the scope described in the claims. Variations and substitutions can be added.

DESCRIPTION OF SYMBOLS 10, 10A, 10B, 10C Field effect transistor 11 Base material 12 Semiconductor layer 13 Source electrode 14 Drain electrode 15 Gate insulating layer 16 Gate electrode

JP 2014-30002 A Patent No. 5965461

Claims (6)

A gate electrode;
A source electrode and a drain electrode;
A semiconductor layer;
A field effect transistor having a gate insulating layer provided between the gate electrode and the semiconductor layer,
A field-effect transistor characterized in that, in a temperature programmed desorption gas analysis method, a release amount of carbon dioxide molecules is 6 × 10 ²¹ molecules / cm ³ or less.   2. The field effect transistor according to claim 1, wherein the gate insulating layer is an oxide film containing an alkaline earth metal and a rare earth element. A drive circuit;
A light control element whose light output is controlled according to a drive signal from the drive circuit,
The display device according to claim 1, wherein the drive circuit drives the light control element by the field effect transistor according to claim 1.   The display element according to claim 3, wherein the light control element is an electroluminescence element, an electrochromic element, a liquid crystal element, an electrophoretic element, or an electrowetting element. A display device in which a plurality of display elements according to claim 3 or 4 are arranged;
A display control device for individually controlling each of the display elements. A display device according to claim 5;
And an image data creation device for supplying image data to the display device.

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