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US 6,784,456 B2Granted
Field effect transistor as well as liquid crystal display using the same
AssigneeNEC Corporation
InventorKenji Sera
Life of this patent
Estimating the term…
Abstract
A gate-overlap-drain structure is obtained by a single pair of a single impurity implantation process and a single laser anneal process, wherein the improved gate-overlap-drain structure includes lightly activated high impurity concentration regions exhibiting substantially the same function as the lightly doped drain regions, wherein the lightly activated high impurity concentration regions are bounded with high impurity concentration regions serving as source and drain regions. The boundaries are self-aligned to edges of a gate electrode. Side regions of the gate electrode overlap the lightly activated high impurity concentration regions.
Claims30
A semiconductor structure in a field effect transistor, said structure comprising:
- a semiconductor layer;
- an insulating layer overlying said semiconductor layer;
- and
- a gate electrode for controlling an electric field applied to at least a part of said semiconductor layer;
- wherein said semiconductor layer further includes:
- at least a lightly activated high impurity concentration layer having a first implanted-impurity concentration value, and a first effectively-activated-impurity concentration range which is lower than said first implanted-impurity concentration value;
- and
- at least a sufficiently activated high impurity concentration layer being bounded with said at least a lightly activated high impurity concentration layer, and said at least a sufficiently activated high impurity concentration layer having a second implanted-impurity concentration value which is substantially the same as said first implanted-impurity concentration value, and a second effectively-activated-impurity concentration value which is higher than said first effectively-activated-impurity concentration range.
5 more elements
A semiconductor structure in a field effect transistor, said structure comprising:
- a semiconductor layer;
- an insulating layer overlying said semiconductor layer;
- and
- a gate electrode for controlling an electric field applied to at least a part of said semiconductor layer;
- wherein said semiconductor layer further includes:
- at least a sufficiently activated high impurity concentration layer being sufficiently activated by a laser beam irradiation, and
- at least a lightly activated high impurity concentration layer being bounded with said at least a sufficiently activated high impurity concentration layer, and said at least a lightly activated high impurity concentration layer being insufficiently activated by a thermal diffusion from said at least a sufficiently activated high impurity concentration layer.
4 more elements
A field effect transistor including:
- a substrate;
- a gate insulating film over said substrate;
- a gate electrode over said gate insulating film;
- and
- source/drain regions over said substrate and under said gate insulating film,
- wherein said drain region further includes:
- at least a lightly activated high impurity concentration layer having a first implanted-impurity concentration value, and a first effectively-activated-impurity concentration range which is lower than said first implanted-impurity concentration value;
- and
- at least a sufficiently activated high impurity concentration layer being bounded with said at least a lightly activated high impurity concentration layer, and said at least a sufficiently activated high impurity concentration layer having a second implanted-impurity concentration value which is substantially the same as said first implanted-impurity concentration value, and a second effectively-activated-impurity concentration value which is higher than said first effectively-activated-impurity concentration range.
6 more elements
A field effect transistor including:
- a substrate;
- a gate insulating film over said substrate;
- a gate electrode over said gate insulating film;
- and
- source/drain regions over said substrate and under said gate insulating film,
- wherein said drain region further includes:
- at least a sufficiently activated high impurity concentration layer being sufficiently activated by a laser beam irradiation, and
- at least a lightly activated high impurity concentration layer being bounded with said at least a sufficiently activated high impurity concentration layer, and said at least a lightly activated high impurity concentration layer being insufficiently activated by a thermal diffusion from said at least a sufficiently activated high impurity concentration layer.
5 more elements
A field effect transistor including:
- a substrate;
- a gate insulating film over said substrate;
- a gate electrode over said gate insulating film;
- and
- source/drain regions over said substrate and under said gate insulating film,
- wherein each of said source/drain regions further includes:
- at least a lightly activated high impurity concentration layer being positioned under said gate electrode, and said at least a lightly activated high impurity concentration layer having a first implanted-impurity concentration value, and a first effectively-activated-impurity concentration range which is lower than said first implanted-impurity concentration value;
- and
- at least a sufficiently activated high impurity concentration layer being bounded with said at least a lightly activated high impurity concentration layer, and a boundary between said at least a lightly activated high impurity concentration layer and said at least a sufficiently activated high impurity concentration layer being aligned to an edge of said gate electrode, and said at least a sufficiently activated high impurity concentration layer having a second implanted-impurity concentration value which is substantially the same as said first implanted-impurity concentration value, and a second effectively-activated-impurity concentration value which is higher than said first effectively-activated-impurity concentration range, and
- wherein said at least a lightly activated high impurity concentration layer has a gentle decrease in a first effectively-activated-impurity concentration value ranged in said first effectively-activated-impurity concentration range as a distance from said at least a sufficiently activated high impurity concentration layer is increased.
7 more elements
A liquid crystal display including a plurality of pixels, each pixel having a liquid crystal cell and a switching device, and said switching device further comprising:
- a thin film field effect transistor including:
- a substrate;
- a gate insulating film over said substrate;
- a gate electrode over said gate insulating film;
- and
- source/drain regions over and substrate and under said gate insulating film,
- wherein each of said source/drain regions further includes:
- at least a lightly activated high impurity concentration layer being positioned under said gate electrode, and said at least a lightly activated high impurity concentration layer having a first implanted-impurity concentration value, and a first effectively-activated-impurity concentration range which is lower than said first implanted-impurity concentration value;
- and
- at least a sufficiently activated high impurity concentration layer being bounded with said at least a lightly activated high impurity concentration layer, and a boundary between said at least a lightly activated high impurity concentration layer and said at least a sufficiently activated high impurity concentration layer being aligned to an edge of said gate electrode, and said at least a sufficiently activated high impurity concentration layer having a second implanted-impurity concentration value which is substantially the same as said first implanted-impurity concentration value, and a second effectively-activated-impurity concentration value which is higher than said first effectively-activated-impurity concentration range, and
- wherein said at least a lightly activated high impurity concentration layer has a gentle decrease in a first effectively-activated-impurity concentration value ranged in said first effectively-activated-impurity concentration range as a distance from said at least a sufficiently activated high impurity concentration layer is increased.
8 more elements
Dependencies are inferred from the claim text.