Field effect transistor
First Claim
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1. A field-effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, whereinthe channel layer comprises an amorphous oxide of a compound having(a) a composition when in crystalline state represented by In2-xM3xO3(Zn1-yM2yO)m, wherein M2 is Mg or Ca;
- M3 is B, Al, Ga or Y;
0≦
x≦
2;
0≦
y≦
1; and
m is zero or a natural number less than 6, or a mixture of said compounds;
(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and
(c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and
at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
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Abstract
A novel field-effect transistor is provided which employs an amorphous oxide. In an embodiment of the present invention, the transistor comprises an amorphous oxide layer containing electron carrier at a concentration less than 1×10−18/cm3, and the gate-insulating layer is comprised of a first layer being in contact with the amorphous oxide and a second layer different from the first layer.
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Citations
24 Claims
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1. A field-effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition when in crystalline state represented by In2-xM3xO3(Zn1-yM2yO)m, wherein M2 is Mg or Ca; - M3 is B, Al, Ga or Y;
0≦
x≦
2;
0≦
y≦
1; and
m is zero or a natural number less than 6, or a mixture of said compounds;(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes. - View Dependent Claims (2, 3, 4, 5, 23, 24)
- M3 is B, Al, Ga or Y;
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6. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition when in crystalline state represented by In2-xM3xO3(Zn1-yM2yO)m, wherein M2 is Mg or Ca; - M3 is B, Al, Ga or Y;
0≦
x≦
2;
0≦
y≦
1; and
m is zero or a natural number less than 6, or a mixture of said compounds;(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and the field-effect transistor has a lamination structure comprised of a first layer in which at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, and a second layer composed of a metal, or the field-effect transistor has a lamination structure comprised of a first layer in which a wiring connected to at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, and a second layer composed of a metal, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
- M3 is B, Al, Ga or Y;
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7. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition when in crystalline state represented by In2-xM3xO3(Zn1-yM2yO)m, wherein M2 is Mg or Ca; - M3 is B, Al, Ga or Y;
0≦
x≦
2;
0≦
y≦
1; and
m is zero or a natural number less than 6, or a mixture of said compounds;(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and the gate insulator is comprised of a first layer being in contact with the amorphous oxide and a second layer different from the first layer and is laminated on the first layer, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes. - View Dependent Claims (8, 9, 10, 11)
- M3 is B, Al, Ga or Y;
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12. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition when in crystalline state represented by In2-xM3xO3(Zn1-yM2yO)m, wherein M2 is Mg or Ca; - M3 is B, Al, Ga or Y;
0≦
x≦
2;
0≦
y≦
1; and
m is zero or a natural number less than 6, or a mixture of said compounds;(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and a passivation layer is provided between the channel layer and the gate insulator, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes. - View Dependent Claims (13, 14)
- M3 is B, Al, Ga or Y;
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15. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer on a substrate, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition when in crystalline state represented by In2-xM3xO3(Zn1-yM2yO)m, wherein M2 is Mg or Ca; - M3 is B, Al, Ga or Y;
0≦
x≦
2;
0≦
y≦
1; and
m is zero or a natural number less than 6, or a mixture of said compounds;(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and a surface-coating layer being provided between the channel layer and the substrate, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes. - View Dependent Claims (16, 17)
- M3 is B, Al, Ga or Y;
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18. A field-effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition selected from an oxide containing In, Ga and Zn, an oxide containing In, Zn and Sn, an oxide containing In and Zn, an oxide containing In and Sn, or an oxide containing In; -
(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
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19. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition selected from an oxide containing In, Ga and Zn, an oxide containing In, Zn and Sn, an oxide containing In and Zn, an oxide containing In and Sn, or an oxide containing In; -
(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and the field-effect transistor has a lamination structure comprised of a first layer in which at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, and a second layer composed of a metal, or the field-effect transistor has a lamination structure comprised of a first layer in which a wiring connected to at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, and a second layer composed of a metal, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
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20. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition selected from an oxide containing In, Ga and Zn, an oxide containing In, Zn and Sn, an oxide containing In and Zn, an oxide containing In and Sn, or an oxide containing In; -
(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and the gate insulator is comprised of a first layer being in contact with the amorphous oxide and a second layer different from the first layer and is laminated on the first layer, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
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21. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition selected from an oxide containing In, Ga and Zn, an oxide containing In, Zn and Sn, an oxide containing In and Zn, an oxide containing In and Sn, or an oxide containing In; -
(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and a passivation layer is provided between the channel layer and the gate insulator, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
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22. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and a transparent channel layer on a substrate, wherein
the channel layer comprises an amorphous oxide of a compound having (a) a composition selected from an oxide containing In, Ga and Zn, an oxide containing In, Zn and Sn, an oxide containing In and Zn, an oxide containing In and Sn, or an oxide containing In; -
(b) an electron carrier concentration of 1012/cm3 or more and less than 1018/cm3, wherein an electron mobility of the channel layer tends to increase with increase of the electron carrier concentration; and (c) an oxygen defect density decreased by treatment in an atmosphere containing oxygen at a predetermined pressure during or after formation of the amorphous oxide; and a surface-coating layer is provided between the channel layer and the substrate, wherein current between the drain electrode and the source electrode when no gate voltage is applied is less than 10 microamperes.
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Specification