JP6904444B2 - Field effect transistors, display elements, image display devices and systems - Google Patents

Description

The present invention relates to a field effect transistor, a display element, an image display device and a system, and more specifically, a field effect transistor having an active layer made of an oxide semiconductor, a display element having the field effect transistor and an image display. The present invention relates to an apparatus and a system including the image display apparatus.

A field effect transistor (FET) controls the current between the source electrode and the drain electrode based on the principle that a voltage is applied to the gate electrode and a gate is provided for the flow of electrons or holes by the electric field of the channel. It is a transistor to do.

FETs are used as switching elements and amplification elements because of their characteristics. In addition to having a low gate current, the FET has a flat structure, so that it is easier to manufacture and integrate as compared with a bipolar transistor. Therefore, it is an indispensable element in integrated circuits used in current electronic devices.

The FET is applied as a thin film transistor (TFT) to an active matrix type display or the like.

In recent years, liquid crystal displays (Liquid Crystal Display: LCD), organic EL (electroluminescence) displays (OLED), electronic papers, and the like have been put into practical use as flat panel displays (FPDs).

These FPDs are driven by a drive circuit including a TFT using amorphous silicon or polycrystalline silicon as an active layer. Further, FPDs are required to have higher size, higher definition, and higher speed driveability, and accordingly, TFTs having high carrier mobility, small changes in characteristics with time, and small variations between elements are required. There is.

However, TFTs using amorphous silicon (a-Si) or polycrystalline silicon (particularly low-temperature polysilicon: LTPS) as active layers have advantages and disadvantages, and it is difficult to satisfy all the requirements at the same time. ..

For example, the a-Si TFT has the drawbacks that the mobility is insufficient to drive a large-screen LCD (Liquid Crystal Display) at high speed, and the threshold voltage shift during continuous driving is large. Although the LTPS-TFT has high mobility, there is a problem that the size of the mother glass in the mass production line cannot be increased due to the large variation in the threshold voltage due to the process of crystallizing the active layer by excimer laser annealing.

Therefore, a new TFT technology that combines the advantages of a-Si TFT and the advantages of LTPS-TFT is required. In order to meet this demand, in recent years, TFTs using oxide semiconductors, which can be expected to have carrier mobility exceeding a-Si, have been actively developed.

_{In particular, InGaZnO 4} (a-IGZO), which can form a film at room temperature and exhibits a mobility of a-Si or higher in an amorphous state, has been proposed (see Non-Patent Document 1). Semiconductors have been energetically studied.

However, in these oxide semiconductors, since carrier electrons are generated by oxygen vacancies, it is necessary to strictly control the oxygen concentration in the film forming process. When trying to achieve high mobility, it tends to be in a depressive state, and the process window for achieving normal off is very narrow. Further, there is a problem that the oxygen concentration in the film changes in the patterning step or the passivation step after the film formation, and the characteristics tend to deteriorate.

In order to solve such a problem, countermeasures have been conventionally considered from two viewpoints. One of them is a measure of compensating for carriers generated by oxygen vacancies by introducing a p-type dopant (for example, ^{replacing In 3+} with Zn ^{2+) in order to keep the carrier concentration low (Patent Document 1 and).} 2). For this measure, a small amount of counter cation is further added to stabilize the p-type dopant (for example, In ³⁺ is ^{replaced with Zn 2+} , and a trace amount of Sn ⁴⁺ is added. [Zn 2 ⁺ ]> [Sn ⁴⁺ ]) (see Patent Document 3). The other is a method of suppressing carrier formation by introducing a certain amount of a metal element (Al, Zr, Hf, etc.) having a high affinity for oxygen (see Non-Patent Document 2).
However, both methods still have problems such as insufficient stability and reduced mobility.

An object of the present invention is to solve the above-mentioned problems in the past and to achieve the following object. That is, in the present invention, carriers are generated by performing n-type substitution doping on the oxide semiconductor of the active layer of the field-effect transistor, and a sufficient amount of oxygen is introduced at the time of film formation to strictly control the oxygen concentration. The purpose is to make it unnecessary, reduce oxygen vacancies, improve the stability of the lattice, and realize the characteristic stability in the subsequent process.

The means for solving the above-mentioned problems are as follows. That is,
The field effect transistor of the present invention
A gate electrode for applying a gate voltage and
Source and drain electrodes for extracting current,
An active layer provided adjacent to the source electrode and the drain electrode and made of an n-type oxide semiconductor, and
A gate insulating layer provided between the gate electrode and the active layer,
It is a field effect transistor equipped with
A triclinic composition compound in which the n-type oxide semiconductor is substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. , A monoclinic composition compound, and a trigonal composition compound.
The valence of the dopant is higher than the valence of the metal ions (excluding the dopant) constituting the n-type oxide semiconductor.

According to the present invention, the above-mentioned problems in the prior art can be solved, and electron carriers are generated by performing n-type substitution doping on the n-type oxide semiconductor which is the active layer of the field-effect transistor to generate electron carriers during film formation. By introducing a sufficient amount of oxygen into the membrane, strict control of oxygen concentration becomes unnecessary, the process margin is expanded, oxygen vacancies are reduced to improve the stability of the transistor, and the characteristics are stabilized in the subsequent process. Can be realized. Therefore, it is possible to reduce the variation between the elements, and it is possible to provide a high-definition, high-quality field-effect transistor having a large area.

FIG. 1 is a schematic configuration diagram showing an example of a top contact / bottom gate type field effect transistor. FIG. 2 is a schematic configuration diagram showing an example of a bottom contact / bottom gate type field effect transistor. FIG. 3 is a schematic configuration diagram showing an example of a top contact / top gate type field effect transistor. FIG. 4 is a schematic configuration diagram showing an example of a bottom contact top gate type field effect transistor. FIG. 5 is a schematic configuration diagram showing an example of a television device as the system of the present invention. FIG. 6 is a diagram (No. 1) for explaining the image display device in FIG. FIG. 7 is a diagram (No. 2) for explaining the image display device in FIG. FIG. 8 is a diagram (No. 3) for explaining the image display device in FIG. FIG. 9 is a diagram for explaining an example of the display element of the present invention. FIG. 10 is a schematic configuration diagram showing an example of the positional relationship between the organic EL element and the field effect transistor in the display element. FIG. 11 is a schematic configuration diagram showing another example of the positional relationship between the organic EL element and the field effect transistor in the display element. FIG. 12 is a schematic configuration diagram showing an example of an organic EL element. FIG. 13 is a diagram for explaining a display control device. FIG. 14 is a diagram for explaining a liquid crystal display. FIG. 15 is a diagram for explaining the display element in FIG. FIG. 16 is a diagram for explaining the characteristics of the field effect transistors of Example 1 and Comparative Example 1. FIG. 17 is a diagram for explaining the relationship between the oxygen concentration during film formation and the field effect mobility of the characteristics of the field effect transistors of Example 1 and Comparative Example 1.

(Field effect transistor)
The field-effect transistor of the present invention has at least a gate electrode, a source electrode, a drain electrode, an active layer, and a gate insulating layer, and further has other members, if necessary.

<Gate electrode>
The gate electrode is not particularly limited as long as it is an electrode for applying a gate voltage, and can be appropriately selected depending on the intended purpose.
The material of the gate electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, metals or alloys such as Mo, Al, Ag and Cu, transparent conductive oxides such as ITO and ATO, and the like. Examples thereof include organic conductors such as polyethylene dioxythiophene (PEDOT) and polyaniline (PANI).

The method for forming the gate electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, (i) a method of forming a film by a sputtering method, a dip coating method or the like, and then patterning by photolithography. ii) Examples thereof include a method of directly forming a desired shape by a printing process such as inkjet, nanoimprint, and gravure.

The average thickness of the gate electrode is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 nm to 1 μm, more preferably 50 nm to 300 nm.

<Source electrode and drain electrode>
The source electrode and the drain electrode are not particularly limited as long as they are electrodes for extracting an electric current, and can be appropriately selected depending on the intended purpose.
The material of the source electrode and the drain electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the same material as the material described in the description of the gate electrode can be mentioned.

The method for forming the source electrode and the drain electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the same method as the forming method described in the description of the gate electrode can be mentioned.

The average thickness of the source electrode and the drain electrode is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 nm to 1 μm, more preferably 50 nm to 300 nm.

<Active layer>
The active layer is a layer provided adjacent to the source electrode and the drain electrode.

Previous studies by the present inventors have shown that electron carriers are generated by n-type doping in highly symmetric oxide semiconductors (see JP2011-192971), but symmetry as described later. It was not always clear that n-type doping works effectively in low-symmetry oxide semiconductors. However, this time, the present inventors have found a combination of an n-type dopant and an oxide semiconductor which is useful even with low symmetry as shown below.

According to the present invention, the material of the active layer was substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. It is an n-type oxide semiconductor which is one of a triclinic composition compound, a monoclinic composition compound, and a trigonal composition compound.
Here, the valence of the dopant is higher than the valence of the metal ions (however, excluding the dopant) constituting the n-type oxide semiconductor.
The substitution doping is also referred to as n-type doping.

<< Triclinic composition compound >>
According to the present invention, the first candidate for the active layer is an n-type oxide semiconductor, which is a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. It is a triclinic composition compound substituted and doped with at least one of the dopants of.

The triclinic composition compound preferably belongs to one of the points C ₁ and C _i.

The triclinic composition compound is a space group No. It preferably belongs to any of 1 and 2.

The triclinic composition compounds include Li, Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, La, Ga, In, Tl, Ge, Sn, Pb, Ti, As, Sb, It preferably contains at least one cation of Bi, V, Nb, Ta, Te, Mo, and W.

The substitution doping is Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Ti, Zr, Hf, Ce, V, Nb, Ta, As, Sb. , Bi, Mo, W, and Te, preferably by introduction of at least one cation.

As examples of these, Cu ₂ WO ₄ , Cd ₂ Ge ₃ O ₈ , HgTeO _{3, and the} like are suitable. Alternatively, these solid solutions may be used. Although the composition is shown here as an integer, unexpected non-stoikiometry and trace impurities are acceptable as long as they do not interfere with the doping described below. In particular, oxygen vacancies are likely to occur, and the composition of oxygen is usually smaller than the value of the demonstrative formula.

The substitution doping, which is n-type doping, includes, for example, a dopant having a higher valence for ^{Cu + , which is a monovalent cation, that is, divalent Mg 2+} , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ^2+. , Cd ²⁺ , Hg ²⁺ , trivalent Al ³⁺ , Ga ³⁺ , In ³⁺ , Tl ³⁺ , Y ³⁺ , La ³⁺ , tetravalent Ge ⁴⁺ , Sn ⁴⁺ , Pb ⁴⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Hf ^{4+ 4+} , pentavalent V ⁵⁺ , Nb ⁵⁺ , Ta ⁵⁺ , As ⁵⁺ , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.
Further, as the substitution doping which is n-type doping, for example, for the divalent cations Cd ²⁺ and Hg ²⁺ , a dopant having a higher valence, that is, trivalent Al ³⁺ , Ga ³⁺ , In ³⁺ , ^{Tl 3+, Y 3+, La 3+} , 4 -valent ^{Ge 4+, Sn 4+, Pb 4+} , Ti 4+, Zr 4+, Hf 4+, Ce 4+, 5 ^{-valent V 5+, Nb 5+, Ta 5+} , As 5+, Sb 5+ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.
The substitution doping, which is an n-type doping, includes, for example, a dopant having a higher valence than the tetravalent ^{cations Ge 4+} and Te ^{4+, that is, pentavalent V 5+} , Nb ⁵⁺ , Ta ⁵⁺ , and As. ⁵⁺ , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , and Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.

It is preferable to select the dopant in consideration of the ionic radius, the coordination number, the orbital energy, and the like. The doping concentration can be appropriately selected depending on the material of the matrix, the type of dopant, the site to be replaced, the film forming process, the desired TFT characteristics, and the like. For example, when a Cu ₂ WO ₄ film doped with Zn is produced by a sputtering method, a target doped with about 1% Zn may be prepared. Since Zn substituting the Cu site forms a donor, the oxygen concentration of the sputter gas can be made higher and the oxygen vacancies can be reduced as compared with the case of producing the _{non-doped Cu 2} WO _4. Further, even in that case, the carrier concentration can be maintained and the contact resistance with the source / drain electrode can be kept low, so that the decrease in mobility can be suppressed. Further, since the sputtering process goes through a highly excited state, carriers can be generated without heating the substrate.
Even when no diffraction line is observed by X-ray diffraction (XRD) or the like and long-range order does not exist (generally called an amorphous state), in the case of an oxide having a rigid structure, oxygen Since the coordination polyhedron (for example, CdO ₆ octahedron) and its connection mode (for example, CdO _6- ridge shared chain) are maintained, the substitution doping works effectively. In such a structure, since the density of states of the tail states peculiar to the amorphous state is small, the sub-gap absorption is small and the photodegradation characteristics are superior to those of the highly amorphous material. On the other hand, in the crystalline state, of course, doping is effective, and the influence of grain boundaries on the conduction band composed of the 4s, 5s, and 6s bands of heavy metal ions is small. However, when the doping amount is excessive and the dopant segregates at the grain boundaries, it is preferable to reduce the dopant concentration. It is also preferable to post-anneal at 200 ° C. to 300 ° C. in order to improve the adhesion and electrical contact between the source / drain electrode and the active layer. Further, it may be annealed at a higher temperature to increase the crystallinity.

<< Monoclinic composition compound >>
According to the present invention, the second candidate for the active layer is an n-type oxide semiconductor, which is a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. It is a monoclinic composition compound substituted-doped with at least one of the dopants of.

The monoclinic composition compound preferably belongs to any of the point groups C ₂ , C _s , and C _{2 h.}

The monoclinic composition compound is a space group No. It preferably belongs to any of 3 to 15.

The monoclinic composition compounds include Li, Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, La, Ga, In, Tl, Ge, Sn, Pb, Ti, As, Sb, It preferably contains at least one cation of Bi, V, Nb, Ta, Te, Mo, and W.

The substitution doping is Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Ti, Zr, Hf, Ce, V, Nb, Ta, As, Sb. , Bi, Mo, W, and Te, preferably by introduction of at least one cation.

As examples of these, SrGa ₂ O ₄ , BaIn ₂ O ₄ , Zn ₂ Ge ₂ O ₆ , Cd ₂ Ge ₂ O _{6, and the} like are suitable. Alternatively, these solid solutions may be used. Although the composition is shown here as an integer, unexpected non-stoikiometry and trace impurities are acceptable as long as they do not interfere with the doping described below. In particular, oxygen vacancies are likely to occur, and the composition of oxygen is usually smaller than the value of the demonstrative formula.

The substitution doping, which is an n-type doping, includes, for example, a dopant having a higher valence for the ^{divalent cations Sr 2+} , Ba ²⁺ , Zn ²⁺ , and Cd ^{2+, that is, trivalent Al 3+} and Ga ^3+. , In ³⁺ , Tl ³⁺ , Y ³⁺ , La ³⁺ , 4-valent Ge ⁴⁺ , Sn ⁴⁺ , Pb ⁴⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Hf ⁴⁺ , Ce ⁴⁺ , 5-valent V ⁵⁺ , Nb ⁵⁺ , Ta ^{5 5+} , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , and Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.
Further, as the substitution doping which is n-type doping, for example, for Ga ³⁺ and In ³⁺ which are trivalent cations, a dopant having a higher valence, that is, tetravalent Ge ⁴⁺ , Sn ⁴⁺ , Pb ⁴⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Hf ⁴⁺ , Ce ⁴⁺ , pentavalent V ⁵⁺ , Nb ⁵⁺ , Ta ⁵⁺ , As ⁵⁺ , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.
Further, as the substitution doping which is n-type doping, for example, ^{for Ge 4+} which is a tetravalent cation, a dopant having a higher valence, that is, pentavalent V ⁵⁺ , Nb ⁵⁺ , Ta ⁵⁺ , As ⁵⁺ , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , and Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.

It is preferable to select the dopant in consideration of the ionic radius, the coordination number, the orbital energy, and the like. The doping concentration can be appropriately selected depending on the material of the matrix, the type of dopant, the site to be replaced, the film forming process, the desired TFT characteristics, and the like. For example, when a W-doped BaIn ₂ O ₄ film is produced by a sputtering method, a target doped with about 0.5% W may be prepared. Since W that replaces the In site forms a donor, the oxygen concentration of the sputter gas can be made higher than that when _{the non-doped BaIn 2} O _{4 is produced, and the oxygen vacancies can be reduced.} Further, even in that case, the carrier concentration can be maintained and the contact resistance with the source / drain electrode can be kept low, so that the decrease in mobility can be suppressed. Further, since the sputtering process goes through a highly excited state, carriers can be generated without heating the substrate. Even when no diffraction line is observed by X-ray diffraction (XRD) or the like and long-range order does not exist (generally called an amorphous state), in the case of an oxide having a rigid structure, oxygen Since the coordination polyhedron (for example, GaO ₆ or InO ₆ octahedron) and its connection mode (for example, InO ₆ ridge covalent chain or surface covalent chain) are maintained, substitution doping works effectively. In such a structure, since the density of states of the tail states peculiar to the amorphous state is small, the sub-gap absorption is small and the photodegradation characteristics are superior to those of the highly amorphous material. On the other hand, in the crystalline state, of course, doping is effective, and the influence of grain boundaries on the conduction band composed of the 4s, 5s, and 6s bands of heavy metal ions is small. However, when the doping amount is excessive and the dopant segregates at the grain boundaries, it is preferable to reduce the dopant concentration. It is also preferable to post-anneal at 200 ° C. to 300 ° C. in order to improve the adhesion and electrical contact between the source / drain electrode and the active layer. Further, it may be annealed at a higher temperature to increase the crystallinity.

<< Trigonal composition compound >>
According to the present invention, the third candidate for the active layer is an n-type oxide semiconductor, which is a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. It is a trigonal composition compound substituted-doped with at least one of the dopants of.

The trigonal composition compound preferably belongs to any of the point groups C _3, C _3i, D _3, C _3v and D _3d.

The trigonal composition compound has a space group No. It preferably belongs to any of 143 to 167.

The trigonal composition compounds include Li, Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, La, Ga, In, Tl, Ge, Sn, Pb, Ti, As, Sb, Bi. , V, Nb, Ta, Te, Mo, and W preferably contain at least one cation.

The substitution doping is Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Ti, Zr, Hf, Ce, V, Nb, Ta, As, Sb. , Bi, Mo, W, and Te, preferably by introduction of at least one cation.

As examples of these, ZnTiO ₃ , Zn ₂ GeO ₄ , In ₂ Zn ₃ O ₆ , Ba ₃ W ₂ O ₉ , Tl ₂ TeO _{6, and the} like are suitable. Alternatively, these solid solutions may be used. Although the composition is shown here as an integer, unexpected non-stoikiometry and trace impurities are acceptable as long as they do not interfere with the doping described below. In particular, oxygen vacancies are likely to occur, and the composition of oxygen is usually smaller than the value of the demonstrative formula.

The substitution doping, which is an n-type doping, includes, for example, a dopant having a higher valence for the ^{divalent cations Ba 2+} and Zn ^{2+, that is, trivalent Al 3+} , Ga ³⁺ , In ³⁺ , and Tl ^3+. , ^{Y 3+, La} 3+, 4-valent ^{Ge 4+, Sn 4+, Pb 4+} , Ti 4+, Zr 4+, Hf 4+, Ce 4+, 5 ^{-valent V 5+, Nb 5+, Ta 5+} , As 5+, Sb 5+, Bi ⁵⁺ and hexavalent Mo ⁶⁺ , W ⁶⁺ , and Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.
The substitution doping, which is an n-type doping, includes, for example, dopants having a higher valence than trivalent ^{cations In 3+} and Tl ^{3+, that is, tetravalent Ge 4+} , Sn ⁴⁺ , Pb ⁴⁺ , and Ti. ⁴⁺ , Zr ⁴⁺ , Hf ⁴⁺ , Ce ⁴⁺ , pentavalent V ⁵⁺ , Nb ⁵⁺ , Ta ⁵⁺ , As ⁵⁺ , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.
Further, as the substitution doping which is an n-type doping, for example, for Ge ⁴⁺ and Ti ⁴⁺ which are tetravalent cations, a dopant having a higher valence, that is, pentavalent V ⁵⁺ , Nb ⁵⁺ , Ta ⁵⁺ , As ⁵⁺ , Sb ⁵⁺ , Bi ⁵⁺ , and hexavalent Mo ⁶⁺ , W ⁶⁺ , Te ⁶⁺ are available. Alternatively, a plurality of these species may be doped.

It is preferable to select the dopant in consideration of the ionic radius, the coordination number, the orbital energy, and the like. The doping concentration can be appropriately selected depending on the material of the matrix, the type of dopant, the site to be replaced, the film forming process, the desired TFT characteristics, and the like. For example, when a Nb-doped ZnTIO ₃ film is produced by a sputtering method, a target doped with about 1% Nb may be prepared. Since the Nb that replaces the Ti site forms a donor, the oxygen concentration of the sputter gas can be made higher than that when the _{non-doped ZnTiO 3 is produced, and the oxygen vacancies can be reduced.} Further, even in that case, the carrier concentration can be maintained and the contact resistance with the source / drain electrode can be kept low, so that the decrease in mobility can be suppressed. Further, since the sputtering process goes through a highly excited state, carriers can be generated without heating the substrate. Even when no diffraction line is observed by X-ray diffraction (XRD) or the like and long-range order does not exist (generally called an amorphous state), in the case of an oxide having a rigid structure, oxygen Since the coordination polyhedron (for example, InO ₆ or TiO ₆ octahedron) and its connection mode (for example, InO ₆ ridge shared chain or face shared chain) are maintained, substitution doping works effectively. In such a structure, since the density of states of the tail states peculiar to the amorphous state is small, the sub-gap absorption is small and the photodegradation characteristics are superior to those of the highly amorphous material. On the other hand, in the crystalline state, of course, doping is effective, and the influence of grain boundaries on the conduction band composed of the 4s, 5s, and 6s bands of heavy metal ions is small. However, when the doping amount is excessive and the dopant segregates at the grain boundaries, it is preferable to reduce the dopant concentration. It is also preferable to post-anneal at 200 ° C. to 300 ° C. in order to improve the adhesion and electrical contact between the source / drain electrode and the active layer. Further, it may be annealed at a higher temperature to increase the crystallinity.

The average thickness of the active layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 nm to 1 μm, more preferably 10 nm to 0.5 μm.

<Gate insulating layer>
The gate insulating layer is not particularly limited as long as it is an insulating layer provided between the gate electrode and the active layer, and can be appropriately selected depending on the intended purpose.
The material of the gate insulating layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, materials already widely used for mass production such as _{SiO 2} and SiN _{x , La 2} O ₃ and the like. Examples _{thereof include high dielectric constant materials such as HfO 2} and organic materials such as polyimide (PI) and fluororesins.

The method for forming the gate insulating layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a vacuum film forming method such as sputtering, chemical vapor deposition (CVD), or atomic layer deposition (ALD). , Spin coating, die coating, printing methods such as inkjet, and the like.

The average thickness of the gate insulating layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 nm to 3 μm, more preferably 100 nm to 1 μm.

The structure of the field-effect transistor is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a top contact / bottom gate type (FIG. 1), a bottom contact / bottom gate type (FIG. 2), and the like. Examples include a top contact / top gate type (FIG. 3) and a bottom contact / top gate type (FIG. 4).
In FIGS. 1 to 4, 21 represents a base material, 22 represents an active layer, 23 represents a source electrode, 24 represents a drain electrode, 25 represents a gate insulating layer, and 26 represents a gate electrode.

The field-effect transistor can be suitably used for a display element described later, but is not limited to this, and can be used, for example, for an IC card, an ID tag, or the like.

<Manufacturing method of field effect transistor>
An example of the method for manufacturing the field effect transistor will be described.

First, a gate electrode is formed on the base material.
The shape, structure, and size of the base material are not particularly limited and may be appropriately selected depending on the intended purpose.
The material of the base material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a glass base material and a plastic base material.
The glass base material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include non-alkali glass and silica glass.
The plastic base material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). Be done.
The base material is preferably subjected to pretreatment such as oxygen plasma, UV ozone, and UV irradiation cleaning from the viewpoint of cleaning the surface and improving the adhesion.

Subsequently, a gate insulating layer is formed on the gate electrode.
Subsequently, an active layer made of an n-type oxide semiconductor is formed on the gate insulating layer in the channel region.
Subsequently, the source electrode and the drain electrode are formed on the gate insulating layer so as to straddle the active layer.
As described above, the field effect transistor is manufactured. In this manufacturing method, for example, a top contact / bottom gate type field effect transistor as shown in FIG. 1 is manufactured.

(Display element)
The display element of the present invention has at least an optical control element and a drive circuit for driving the optical control element, and further includes other members, if necessary.

<Optical control element>
The optical control element is not particularly limited as long as it is an element that controls the optical output according to the drive signal, and can be appropriately selected depending on the intended purpose. For example, an electroluminescence (EL) element or an electrochromic (EL) element. EC) elements, liquid crystal elements, electrophoresis elements, electrowetting elements and the like can be mentioned.

<Drive circuit>
The drive circuit is not particularly limited as long as it has the field-effect transistor of the present invention, and can be appropriately selected depending on the intended purpose.

<Other parts>
The other members are not particularly limited and may be appropriately selected depending on the intended purpose.

Since the display element has the field-effect transistor of the present invention, it is possible to drive at high speed, have a long life, and reduce variations between the elements. Further, the drive transistor can be operated at a constant gate voltage even if the display element changes with time.

(Image display device)
The image display device of the present invention has at least a plurality of display elements, a plurality of wirings, a display control device, and, if necessary, other members.

<Multiple display elements>
The plurality of display elements are not particularly limited as long as they are a plurality of the display elements of the present invention arranged in a matrix, and can be appropriately selected depending on the intended purpose.

<Multiple wiring>
The plurality of wirings are not particularly limited 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, and can be appropriately selected depending on the intended purpose.

<Display control device>
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 the plurality of wirings according to the image data, and is not particularly limited, depending on the purpose. It can be selected as appropriate.

<Other parts>
The other members are not particularly limited and may be appropriately selected depending on the intended purpose.

Since the image display device has the display element of the present invention, it is possible to reduce variations between the elements and display a high-quality image on a large screen.

(system)
The system of the present invention has at least the image display device of the present invention 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 image display device.

Since the system includes the image display device of the present invention, it is possible to display image information in high definition.

Hereinafter, the display element, the image display device, and the system of the present invention will be described with reference to the drawings.
First, the television apparatus as the system of the present invention will be described with reference to FIG.

In FIG. 5, the television apparatus 100 includes a main controller 101, a tuner 103, an AD converter (ADC) 104, a demodulation circuit 105, a TS (Transport Stream) decoder 106, an audio decoder 111, a DA converter (DAC) 112, and an audio output. Circuit 113, speaker 114, video decoder 121, video / OSD synthesis circuit 122, video output circuit 123, image display device 124, OSD drawing circuit 125, memory 131, operating device 132, drive interface (drive IF) 141, hard disk device 142 , An optical disk device 143, an IR receiver 151, and a communication control device 152.
The video decoder 121, the video / OSD synthesis circuit 122, the video output circuit 123, and the OSD drawing circuit 125 constitute an image data creation device.

The main control device 101 is composed of a CPU, a flash ROM, a RAM, and the like, and controls the entire television device 100.
The flash ROM stores a program written in a code that can be deciphered by the CPU, various data used for processing by the CPU, and the like.
The RAM is a working memory.

The tuner 103 selects a preset channel broadcast from the broadcast waves received by the antenna 210.

The ADC 104 converts the output signal (analog information) of the tuner 103 into digital information.

The demodulation circuit 105 demodulates the digital information from the ADC 104.

The TS decoder 106 TS decodes the output signal of the demodulation circuit 105 and separates the audio information and the video information.

The audio decoder 111 decodes the audio information from the TS decoder 106.

The DA converter (DAC) 112 converts the output signal of the audio decoder 111 into an analog signal.

The audio output circuit 113 outputs the output signal of the DA converter (DAC) 112 to the speaker 114.

The video decoder 121 decodes the video information from the TS decoder 106.

The video / OSD synthesis circuit 122 synthesizes the output signal of the video decoder 121 and the output signal of the OSD drawing circuit 125.

The video output circuit 123 outputs the output signal of the video / OSD synthesis circuit 122 to the image display device 124.

The OSD drawing circuit 125 includes a character generator for displaying characters and figures on the screen of the image display device 124, and outputs a signal including display information in response to instructions from the operating device 132 and the IR receiver 151. Generate.

AV (Audio-Visual) data and the like are temporarily stored in the memory 131.

The operation device 132 includes, for example, an input medium (not shown) such as a control panel, and notifies the main control device 101 of various information input by the user.

The drive IF 141 is a bidirectional communication interface, and conforms to ATAPI (AT Attachment Packet Interface) as an example.

The hard disk device 142 is composed of a hard disk, a drive device for driving the hard disk, and the like. The drive device records the data on the hard disk and reproduces the data recorded on the hard disk.

The optical disk device 143 records data on an optical disk (for example, a DVD) and reproduces the data recorded on the optical disk.

The IR receiver 151 receives the optical signal from the remote controller transmitter 220 and notifies the main control device 101.

The communication control device 152 controls communication with the Internet. Various information can be obtained via the Internet.

FIG. 6 is a schematic configuration diagram showing an example of the image display device of the present invention.
In FIG. 6, the image display device 124 has a display device 300 and a display control device 400.
As shown in FIG. 7, the display 300 has a display 310 in which a plurality of (here, n × m) display elements 302 are arranged in a matrix.
Further, as shown in FIG. 8, the display 310 has n scanning lines (X0, X1, X2, X3, ..., Xn-2, Xn) arranged at equal intervals along the X-axis direction. -1) and m data lines (Y0, Y1, Y2, Y3, ..., Ym-1) arranged at equal intervals along the Y-axis direction, at equal intervals along the Y-axis direction. It has m arranged current supply lines (Y0i, Y1i, Y2i, Y3i, ..., Ym-1i).
Therefore, the display element can be specified by the scanning line and the data line.

Hereinafter, the display element of the present invention will be described with reference to FIG.
FIG. 9 is a schematic configuration diagram showing an example of the display element of the present invention.
As shown in FIG. 9 as an example, the display element includes an organic EL (electroluminescence) element 350 and a drive circuit 320 for causing the organic EL element 350 to emit light. That is, the display 310 is a so-called active matrix type organic EL display. Further, the display 310 is a color-compatible 32-inch display. The size is not limited to this.

FIG. 10 shows an example of the positional relationship between the organic EL element 350 in the display element 302 and the field effect transistor 20 as a drive circuit. Here, the organic EL element 350 is arranged next to the field effect transistor 20. The field effect transistor 10 and the capacitor (not shown) are also formed on the same base material.

Although not shown in FIG. 10, it is also preferable to provide a protective film on the upper part of the active layer 22. As the material of the protective film, SiO ₂ , SiN _x , Al ₂ O ₃ , a fluorine-based polymer and the like can be appropriately used.

Further, for example, as shown in FIG. 11, the organic EL element 350 may be arranged on the field effect transistor 20. In this case, since the gate electrode 26 is required to be transparent, the gate electrode 26 is provided with ITO, In ₂ O ₃ , SnO ₂ , ZnO, Ga-added ZnO, and Al-added ZnO, Sb. A conductive transparent oxide such as _{SnO 2} to which is added is used. Reference numeral 360 is an interlayer insulating film (flattening film). Polyimide, acrylic resin, or the like can be used for this interlayer insulating film.

FIG. 12 is a schematic configuration diagram showing an example of an organic EL element.
In FIG. 12, the organic EL element 350 has a cathode 312, an anode 314, and an organic EL thin film layer 340.

The material of the cathode 312 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, aluminum (Al), magnesium (Mg) -silver (Ag) alloy, aluminum (Al) -lithium (Li). Examples thereof include alloys and ITO (Indium Tin Oxide). The magnesium (Mg) -silver (Ag) alloy becomes a high reflectance electrode if it is sufficiently thick, and becomes a translucent electrode if it is an ultrathin film (less than about 20 nm). In FIG. 12, light is extracted from the anode side, but light can be extracted from the cathode side by using a transparent or translucent electrode as the cathode.

The material of the anode 314 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), silver (Ag) -neodymium (Nd) alloy and the like can be selected. Can be mentioned. When a silver alloy is used, it becomes a high reflectance electrode and is suitable for extracting light from the cathode side.

The organic EL thin film layer 340 has an electron transport layer 342, a light emitting layer 344, and a hole transport layer 346. The electron transport layer 342 is connected to the cathode 312, and the hole transport layer 346 is connected to the anode 314. When a predetermined voltage is applied between the anode 314 and the cathode 312, the light emitting layer 344 emits light.

Here, the electron transport layer 342 and the light emitting layer 344 may form one layer, an electron injection layer may be provided between the electron transport layer 342 and the cathode 312, and further, hole transport may be provided. A hole injection layer may be provided between the layer 346 and the anode 314.

Further, although the case of so-called "bottom emission" in which light is extracted from the base material side has been described, it may be "top emission" in which light is extracted from the side opposite to the base material.

The drive circuit 320 in FIG. 9 will be described.
The drive circuit 320 has two field effect transistors 10 and 20 and a capacitor 30.

The field effect transistor 10 operates as a switch element. The gate electrode G of the field-effect transistor 10 is connected to a predetermined scanning line, and the source electrode S of the field-effect transistor 10 is connected to a predetermined data line. Further, the drain electrode D of the field effect transistor 10 is connected to one terminal of the capacitor 30.

The field effect transistor 20 supplies a current to the organic EL element 350. The gate electrode G of the field effect transistor 20 is connected to the drain electrode D of the field effect transistor 10. The drain electrode D of the field effect transistor 20 is connected to the anode 314 of the organic EL element 350, and the source electrode S of the field effect transistor 20 is connected to a predetermined current supply line.

The capacitor 30 stores the state of the field effect transistor 10, that is, data. The other terminal of the capacitor 30 is connected to a predetermined current supply line.

Therefore, when the field-effect transistor 10 is in the "on" state, image data is stored in the capacitor 30 via the signal line Y2, and even after the field-effect transistor 10 is in the "off" state, the field-effect transistor 10 is stored. The organic EL element 350 is driven by holding 20 in the "on" state corresponding to the image data.

FIG. 13 is a schematic configuration diagram showing another example of the image display device of the present invention.
In FIG. 13, the image display device includes a display element 302, wiring (scanning line, data line, current supply line), and a display control device 400.
The display control device 400 includes an image data processing circuit 402, a scanning line drive circuit 404, and a data line drive circuit 406.
The image data processing circuit 402 determines the brightness of the plurality of display elements 302 in the display based on the output signal of the video output circuit 123.
The scanning line drive circuit 404 individually applies a voltage to the n scanning lines according to the instruction of the image data processing circuit 402.
The data line drive circuit 406 individually applies a voltage to m data lines in response to an instruction from the image data processing circuit 402.

Further, in the above embodiment, the case where the optical control element is an organic EL element has been described, but the present invention is not limited to this, and for example, the optical control element may be an electrochromic element. In this case, the display becomes an electrochromic display.

Further, the optical control element may be a liquid crystal element, in which case the display becomes a liquid crystal display, and as shown in FIG. 14, a current supply line for the display element 302'is unnecessary. Further, as shown in FIG. 15, the drive circuit 320'can be composed of one field effect transistor 40 similar to the field effect transistors 10 and 20. In the field effect transistor 40, the gate electrode G is connected to a predetermined scanning line, and the source electrode S is connected to a predetermined data line. Further, the drain electrode D is connected to the pixel electrode of the capacitor 361 and the liquid crystal element 370.

Further, the optical control element may be an electrophoresis element, an inorganic EL element, or an electrowetting element.

The case where the system of the present invention is a television device has been described above, but the present invention is not limited to this, and an image display device 124 may be provided as a device for displaying images and information. For example, it may be a computer system in which a computer (including a personal computer) and an image display device 124 are connected.

In addition, the image display device 124 is used as a display means in mobile information devices such as mobile phones, portable music playback devices, portable video playback devices, electronic books, PDAs (Personal Digital Assistants), and imaging devices such as still cameras and video cameras. Can be used. Further, the image display device 124 can be used as a display means for displaying various information in a mobile system such as a car, an aircraft, a train, or a ship. Further, the image display device 124 can be used as a display means for displaying various information in the measuring device, the analyzer, the medical device, and the advertising medium.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples.

(Example 1)
The non-alkali glass substrate was ultrasonically cleaned with a neutral detergent, pure water, and isopropyl alcohol. After the substrate was dried, UV-ozone treatment was further performed at 90 ° C. for 10 minutes.
Mo was formed into a 100 nm film on the substrate by a DC magnetron sputtering method and patterned by a photolithography method to form a gate electrode. _{Next, SiO 2} was formed into a 200 nm film by the RF magnetron sputtering method to form a gate insulating layer. Next, using a BaIn _1.98 Sn _0.02 O ₄ sintered body target, a Sn-doped BaIn ₂ O ₄ film was formed at 50 nm by an RF magnetron sputtering method. Argon gas and oxygen gas were introduced as the sputtering gas. The total pressure was fixed at 1.1 Pa, and the oxygen concentration was changed in the range of 4% to 60% as a parameter to prepare an active layer. The patterning was performed by forming a film through a metal mask. Next, as a source / drain electrode, 100 nm of Al was vapor-deposited via a metal mask. The channel length was 50 μm and the channel width was 400 μm. Finally, an electric field effect transistor was manufactured by annealing in the air at 300 ° C. for 1 hour. _{In addition, BaIn 2} O ₄ doped with Sn, which is an active layer, has a point group C _2h and a space group No. It has 14 symmetries.

(Comparative Example 1)
In the above-mentioned field-effect transistor manufacturing procedure of Example 1, the active layer was formed by changing the _{sintered body target at the time of manufacturing the active layer to BaIn 2} O _{4 as shown in Table 1 below.} A field effect transistor was manufactured in the same manner as in 1.

(Examples 2-36)
In the above-mentioned field-effect transistor manufacturing procedure of Example 1, the active layer is formed by changing the sintered body target of the active layer manufacturing process as shown in Tables 2 and 3 below. In the same manner, a field effect transistor was manufactured.

<Evaluation result>
Table 1 shows the evaluation results of the mobility of the field-effect transistor when the oxygen concentrations at the time of forming the active layer in Example 1 and Comparative Example 1 were 4% and 40%.
The mobility was calculated based on the transfer characteristics.

FIG. 16 shows the transfer characteristics (Vds = 20V) of the field-effect transistor of the sample having an oxygen concentration of 40% at the time of forming the active layer in Example 1 and Comparative Example 1. In Example 1 in which the active layer was doped with Sn, the rising on-voltage (Von) was 0 V, the mobility was 4.5 cm ² / Vs, and the on-off ratio was 8 digits, showing good characteristics of normally off. On the other hand, in Comparative Example 1 in which the active layer was not doped, the on-voltage (Von) was 1.5 V, the mobility was 0.2 cm ² / Vs, and the on-off ratio was 7 digits. It shifted to the plus side and the mobility decreased.
In FIG. 16, "E" represents "a power of 10". For example, "E-04" is "0.0001".

Further, FIG. 17 shows the relationship between the oxygen concentration during film formation and the field effect mobility of the field effect transistors of Example 1 and Comparative Example 1. In Example 1, the mobility was about 4.7 ± 0.4 cm ² / Vs and was almost constant from the oxygen concentration of 4% to 60%, and there was no oxygen concentration dependence. On the other hand, in Comparative Example 1, the mobility was equivalent to that of Example 1 at an oxygen concentration of 4%, but the mobility decreased substantially monotonously as the oxygen concentration increased, and decreased to 1/10 or less at an oxygen concentration of 40%. The reason for these is that in Example 1, by introducing Sn and n-type doping, carriers are generated from Sn in which Ba sites are replaced, so that the oxygen concentration is kept substantially constant even if the oxygen concentration is increased. On the other hand, in Comparative Example 1 without doping, the oxygen vacancies in the active layer decreased as the oxygen concentration increased, so that the carrier concentration decreased, the contact resistance with the source / drain electrode increased, and the mobility increased. It is probable that the decrease in degree was observed.

Next, Tables 2 and 3 show the evaluation results of the mobility of the field-effect transistor when the oxygen concentration at the time of forming the active layer in Examples 2 to 36 was 4% and 40%. Similar to Example 1, it was found that there was no change in mobility at oxygen concentrations of 4% and 40%. That is, it is considered that the substituted cations acted as n-type dopants to generate electron carriers and exhibited constant characteristics regardless of the amount of oxygen.

表２及び３中、結晶系における「Ｔ」は、「三斜晶」を表し、「Ｍ」は「単斜晶」を表し、「Ｒ」は、「菱面体（三方晶）」を表す。

In Tables 2 and 3, "T" in the crystal system represents "triclinic crystal", "M" represents "monoclinic crystal", and "R" represents "rhombohedral (trigonal crystal)".

That is, a field-effect transistor having an n-type oxide semiconductor in which cations are substituted-doped to generate electron carriers as an active layer includes an oxide semiconductor in which carriers are generated by controlling only the amount of oxygen as an active layer. Compared with field-effect transistors, it showed stable and high mobility over a wide process range, and it was shown that good normal-off characteristics can be obtained.

As described above, the field effect transistor of the present invention is suitable for expanding the process margin and stabilizing the TFT characteristics at a high level. Further, according to the display element of the present invention, it is possible to drive at high speed, and it is suitable for reducing the variation between the elements and improving the reliability. Further, according to the image display device of the present invention, it is suitable for displaying a high quality image on a large screen. In addition, the system of the present invention can display image information in high definition, and can be suitably used for television devices, computer systems, and the like.

Aspects of the present invention are, for example, as follows.
<1> A gate electrode for applying a gate voltage and
Source and drain electrodes for extracting current,
An active layer provided adjacent to the source electrode and the drain electrode and made of an n-type oxide semiconductor, and
A gate insulating layer provided between the gate electrode and the active layer,
It is a field effect transistor equipped with
A triclinic composition compound in which the n-type oxide semiconductor is substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. , A monoclinic composition compound, and a trigonal composition compound.
The field-effect transistor is characterized in that the valence of the dopant is larger than the valence of the metal ions (however, excluding the dopant) constituting the n-type oxide semiconductor.
<2> Triclinic crystal in which the n-type oxide semiconductor is substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. The electric field effect transistor according to <1>, which is a composition compound.
<3> the triclinic composition compounds, belongs to one of the points _{C 1} and _{C i,}
The substitution doping is Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Ti, Zr, Hf, Ce, V, Nb, Ta, As, Sb. , Bi, Mo, W, and Te. The field effect transistor according to <2>, which is introduced by introducing at least one cation.
<4> The triclinic composition compound is the space group No. It belongs to any of 1 and 2, and Li, Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, La, Ga, In, Tl, Ge, Sn, Pb, Ti, As, Sb. , Bi, V, Nb, Ta, Te, Mo, and W. The field effect transistor according to <3>, which contains at least one of the cations.
<5> A monoclinic crystal in which the n-type oxide semiconductor is substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. The electric field effect transistor according to <1>, which is a composition compound.
<6> The monoclinic composition compound belongs to any of _{the point groups C 2} , C _s , and C _{2 h.}
The substitution doping is Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Ti, Zr, Hf, Ce, V, Nb, Ta, As, Sb. , Bi, Mo, W, and Te. The field effect transistor according to <5>, which is introduced by introducing at least one cation.
<7> The monoclinic composition compound is the space group No. It belongs to any of 3 to 15, and Li, Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, La, Ga, In, Tl, Ge, Sn, Pb, Ti, As, Sb. , Bi, V, Nb, Ta, Te, Mo, and W. The field effect transistor according to <6>, which contains at least one of the cations.
<8> A trigonal composition in which the n-type oxide semiconductor is substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation. The electric field effect transistor according to <1>, which is a compound.
<9> The trigonal composition compound belongs to any of _{the point groups C 3,} C _3i, D _3, C _3v and D _3d.
The substitution doping is Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Ti, Zr, Hf, Ce, V, Nb, Ta, As, Sb. , Bi, Mo, W, and Te. The field effect transistor according to the above <8> by introducing at least one cation.
<10> The trigonal composition compound is the space group No. It belongs to any of 143 to 167, and belongs to Li, Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, La, Ga, In, Tl, Ge, Sn, Pb, Ti, As, Sb. , Bi, V, Nb, Ta, Te, Mo, and W. The field effect transistor according to <9>, which contains at least one of the cations.
<11> An optical control element whose optical output is controlled according to a drive signal, and
A drive circuit including the field-effect transistor according to any one of <1> to <10> and driving the optical control element, and
It is a display element characterized by being provided with.
<12> The display element according to <11>, wherein the optical control element includes either an electroluminescence element or an electrochromic element.
<13> The display element according to <11>, wherein the optical control element includes either a liquid crystal element or an electrophoresis element.
<14> An image display device that displays an image according to image data.
The display element according to any one of <11> to <13> arranged in a matrix.
A plurality of wirings for individually applying a gate voltage to each field effect transistor in the plurality of display elements, and
A display control device that individually controls the gate voltage of each field effect transistor according to the image data via the plurality of wirings.
It is an image display device characterized by being provided with.
<15> The image display device according to <14> and
An image data creation device that creates image data based on the image information to be displayed and outputs the image data to the image display device.
It is a system characterized by being provided with.

10 Field-effect transistor 20 Field-effect transistor 21 Base material 22 Active layer 23 Source electrode 24 Drain electrode 25 Gate insulation layer 26 Gate electrode 30 Capacitor 40 Field-effect transistor 100 Television device 101 Main controller 103 Tuner 104 AD converter ( ADC)
105 Demodulation circuit 106 TS (Transport Stream) decoder 111 Audio decoder 112 DA converter (DAC)
113 Audio output circuit 114 Speaker 121 Video decoder 122 Video / OSD synthesis circuit 123 Video output circuit 124 Image display device 125 OSD drawing circuit 131 Memory 132 Operation device 141 Drive interface (drive IF)
142 Hard disk device 143 Optical disk device 151 IR receiver 152 Communication control device 210 Antenna 220 Remote control transmitter 300 Display 302, 302'Display element 310 Display 312 Cathode 314 Anode 320, 320' Drive circuit (drive circuit)
340 Organic EL thin film layer 342 Electron transport layer 344 Light emitting layer 346 Hole transport layer 350 Organic EL element 360 Interlayer insulating film 361 Capsule 370 Liquid crystal element 400 Display control device 402 Image data processing circuit 404 Scanning line drive circuit 406 Data line drive circuit

Japanese Unexamined Patent Publication No. 2002-76356 Japanese Unexamined Patent Publication No. 2006-165529 International Publication WO2008-096768 Pamphlet

K. Nomura, 5 others, "Room-temperature fabrication of semiconductor flexible thin-film transistors" 25, NOVEMBER, 2004, p. 488-492 J. S. Park, 5 others, "Novell ZrInZnO Thin-film Transistor with Excellent Stability", Advanced Materials, VOL21, No. 3, 2009, p. 329-333

Claims (8)

A compound substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation.
The valence of the dopant is greater than the valence of the substituted metal cations (excluding the dopant) that make up the compound.
The combination of the substituted metal cation and the dopant cation (substituted metal: dopant) is (Cu: Zn), (Ge: Sb), (Hg: Tl), (Ga: Zr), (Pb: Bi), (Nb: Mo), (Bi: Te), (Li: Mg) , ( V: Mo) , ( As: Mo), (La: Hf), (Tl: Pb), (Ta: W) , (Sb: W), (Ge: As), (Ag: Cd), and (Ba: La).
An oxide semiconductor compound film characterized by the above. A compound substituted-doped with at least one dopant of a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, and a hexavalent cation.
The valence of the dopant is greater than the valence of the substituted metal cations (excluding the dopant) that make up the compound.
The combination of the substituted metal cation and the dopant cation (substituted metal: dopant) is (In: Sn), (Sn: Sb), (Cd: In), (Hg: Tl), (V: An oxide semiconductor compound film characterized by being either Mo) or (Zn: Ge) and further containing at least one of Li, Te, and Ba. A field effect transistor comprising the oxide semiconductor compound film according to claim 1 or 2. An optical control element whose optical output is controlled according to a drive signal,
A display element including the field effect transistor according to claim 3, further comprising a drive circuit for driving the optical control element. The display element according to claim 4, wherein the optical control element includes either an electroluminescence element or an electrochromic element. The display element according to claim 4, wherein the optical control element includes either a liquid crystal element or an electrophoresis element. An image display device that displays an image according to the image data.
The display element according to any one of claims 4 to 6, which is arranged in a matrix.
A plurality of wirings for individually applying a gate voltage to each field effect transistor in the plurality of display elements, and
A display control device that individually controls the gate voltage of each field effect transistor according to the image data via the plurality of wirings.
An image display device comprising. The image display device according to claim 7 and
An image data creation device that creates image data based on the image information to be displayed and outputs the image data to the image display device.
A system characterized by being equipped with.

Images