THIN-FILM TRANSISTOR, METHOD OF PRODUCING THE SAME, AND DEVICES PROVIDED WITH THE SAME
First Claim
1. A thin-film transistor comprising an oxide semiconductor layer, a source electrode, a drain electrode, a gate insulating film and a gate electrode formed on a substrate,wherein the oxide semiconductor layer comprises a first area, a second area and a third area forming a well-type potential in a film-thickness direction, the first area forming a well of the well-type potential and having a first electron affinity, the second area being disposed nearer to the gate electrode than the first area and having a second electron affinity smaller than the first electron affinity, and the third area being disposed farther from the gate electrode than the first area and having a third electron affinity smaller than the first electron affinity, andwherein at least an oxygen concentration at the third area is lower than an oxygen concentration at the first area.
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Accused Products
Abstract
A thin-film transistor including an oxide semiconductor layer is disclosed. The oxide semiconductor layer includes a first area, a second area and a third area forming a well-type potential in the film-thickness direction. The first area forms a well of the well-type potential and has a first electron affinity. The second area is disposed nearer to the gate electrode than the first area and has a second electron affinity smaller than the first electron affinity. The third area is disposed farther from the gate electrode than the first area and has a third electron affinity smaller than the first electron affinity. At least an oxygen concentration at the third area is lower than an oxygen concentration at the first area.
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Citations
26 Claims
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1. A thin-film transistor comprising an oxide semiconductor layer, a source electrode, a drain electrode, a gate insulating film and a gate electrode formed on a substrate,
wherein the oxide semiconductor layer comprises a first area, a second area and a third area forming a well-type potential in a film-thickness direction, the first area forming a well of the well-type potential and having a first electron affinity, the second area being disposed nearer to the gate electrode than the first area and having a second electron affinity smaller than the first electron affinity, and the third area being disposed farther from the gate electrode than the first area and having a third electron affinity smaller than the first electron affinity, and wherein at least an oxygen concentration at the third area is lower than an oxygen concentration at the first area.
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15. A method of producing a thin-film transistor including an oxide semiconductor layer, a source electrode, a drain electrode, a gate insulating film and a gate electrode formed on a substrate, the method comprising:
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a film formation step of forming the oxide semiconductor layer through sputtering, wherein the oxide semiconductor layer comprises a first area, a second area and a third area forming a well-type potential in a film-thickness direction, the first area forming a well of the well-type potential and having a first electron affinity, the second area being disposed nearer to the gate electrode than the first area and having a second electron affinity smaller than the first electron affinity, and the third area being disposed farther from the gate electrode than the first area and having a third electron affinity smaller than the first electron affinity, wherein the film formation step comprises forming the first area under a first value of oxygen partial pressure/argon partial pressure in a film formation chamber, forming the second area under a second value of oxygen partial pressure/argon partial pressure in the film formation chamber, and forming the third area under a third value of oxygen partial pressure/argon partial pressure in the film formation chamber lower than the first value of oxygen partial pressure/argon partial pressure. - View Dependent Claims (16, 19)
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17. A method of producing a thin-film transistor including an oxide semiconductor layer, a source electrode, a drain electrode, a gate insulating film and a gate electrode formed on a substrate, the method comprising:
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a film formation step of forming the oxide semiconductor layer through sputtering, wherein the oxide semiconductor layer comprises a first area, a second area and a third area forming a well-type potential in a film-thickness direction, the first area forming a well of the well-type potential and having a first electron affinity, the second area being disposed nearer to the gate electrode than the first area and having a second electron affinity smaller than the first electron affinity, and the third area being disposed farther from the gate electrode than the first area and having a third electron affinity smaller than the first electron affinity, wherein the film formation process comprises applying oxygen-containing radicals to a surface on which the first area is formed during and/or after formation of the first area. - View Dependent Claims (20)
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18. A method of producing a thin-film transistor including an oxide semiconductor layer, a source electrode, a drain electrode, a gate insulating film and a gate electrode formed on a substrate, the method comprising:
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a film formation step of forming the oxide semiconductor layer through sputtering, wherein the oxide semiconductor layer comprises a first area, a second area and a third area forming a well-type potential in a film-thickness direction, the first area forming a well of the well-type potential and having a first electron affinity, the second area being disposed nearer to the gate electrode than the first area and having a second electron affinity smaller than the first electron affinity, and the third area being disposed farther from the gate electrode than the first area and having a third electron affinity smaller than the first electron affinity, wherein the film formation process comprises applying ultraviolet light in an ozone atmosphere to a surface on which the first area is formed during and/or after formation of the first area. - View Dependent Claims (21)
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Specification