Thin film transistor

A thin film transistor mounted on an insulator substrate, comprising a semiconductor thin film, a gate insulation film formed in contact with the semiconductor thin film and a gate electrode, wherein the semiconductor thin film includes a first impurity region and a second impurity region opposed to each other and a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is minimum or maximum near an interface between the insulator substrate and the semiconductor thin film.

A thin film transistor mounted on an insulator substrate, comprising at least one insulation layer between the insulator substrate and the thin film transistor, a semiconductor thin film, a gate insulation film formed in contact with the semiconductor thin film, and a gate electrode, wherein the semiconductor thin film includes a first impurity region and a second impurity region opposed to each other and a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is minimum or maximum near an interface between the gate insulation film and the semiconductor thin film.

A thin film transistor mounted on an insulator substrate, comprising at least one insulation layer between the insulator substrate and the thin film transistor, a semiconductor thin film, a gate insulation film formed in contact with the semiconductor thin film, and a gate electrode, wherein the semiconductor thin film includes a first impurity region and a second impurity region opposed to each other and a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is minimum or maximum near an interface between the insulation layer and the semiconductor thin film.

A thin film transistor mounted on an insulator substrate, comprising a semiconductor thin film formed in contact with the insulator substrate, a gate insulation film formed in contact with the semiconductor thin film, and a gate electrode, wherein the semiconductor thin film includes a first impurity region and a second impurity region opposed to each other and a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is minimum near an interface between the gate insulation film and the semiconductor thin film and is maximum near an interface between the insulator substrate and the semiconductor thin film.

A thin film transistor mounted on an insulator substrate, comprising a semiconductor thin film formed in contact with the insulator substrate, a gate insulation film formed in contact with the semiconductor thin film, and a gate electrode, wherein the semiconductor thin film includes a first impurity region and a second impurity region opposed to each other and a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is maximum near an interface between the gate insulation film and the semiconductor thin film and is minimum near an interface between the insulator substrate and the semiconductor thin film.

A thin film transistor mounted on an insulator substrate, comprising at least one insulation layer formed between the insulator substrate and the thin film transistor, a semiconductor thin film formed in contact with the insulation layer, a gate insulation film formed in contact with the semiconductor thin film and a gate electrode, wherein the semiconductor thin film has a first impurity region and a second impurity region opposed to each other and has a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is minimum near an interface between the gate insulation film and the semiconductor thin film and is maximum near an interface between the insulation layer and the semiconductor thin film.

A thin film transistor mounted on an insulator substrate, comprising at least one insulation layer formed between the insulator substrate and the thin film transistor, a semiconductor thin film formed in contact with the insulation layer, a gate insulation film formed in contact with the semiconductor thin film and a gate electrode, wherein the semiconductor thin film has a first impurity region and a second impurity region opposed to each other and has a third impurity region disposed adjacent to at least one of the first impurity region and the second impurity region, and an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and wherein a concentration distribution of the impurity concentration in the third impurity region in a direction crossing the insulator substrate is maximum near an interface between the gate insulation film and the semiconductor thin film and is minimum near an interface between the insulation layer and the semiconductor thin film.

A thin film transistor as defined in claim 14, wherein a portion of projection of the gate electrode overlaps the third impurity region.

A thin film transistor device comprising a thin film transistor mounted on an insulator substrate, the thin film transistor comprising a semiconductor thin film, a gate insulation film overlying the semiconductor thin film, and a gate electrode, wherein the semiconductor thin film includes a first impurity region and a second impurity region opposed to each other and a third impurity region disposed adjacent to at least one of the first and second impurity regions, an impurity concentration in the third impurity region is lower than an impurity concentration in the first impurity region or the second impurity region, and an impurity concentration distribution of the third impurity region in a thickness direction of the semiconductor thin film has a peak shifted substantially from a center of the third impurity region in the thickness direction.