Transistor having recess channel and fabricating method thereof
First Claim
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1. A method for fabricating a transistor, comprising:
- forming a trench in a substrate;
forming a polysilicon layer over the substrate and filled in the trench;
etching the polysilicon layer in a manner that a portion of the polysilicon layer having a greater thickness over an edge portion of a bottom surface of the trench than over a middle portion of the bottom surface of the trench remains in the trench;
oxidizing the entire remaining portion of the polysilicon layer to form an insulation layer over the bottom surface of the trench and forming a gate insulation layer over inner sidewalls of the trench to a smaller thickness than the insulation layer at substantially the same time; and
forming a gate electrode over the insulation layer and filled in the trench.
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Abstract
A transistor includes a substrate including a trench, an insulation layer filled in a portion of the trench, the insulation layer having a greater thickness over an edge portion of a bottom surface of the trench than over a middle portion of the bottom surface of the trench, a gate insulation layer formed over inner sidewalls of the trench, the gate insulation layer having a thickness smaller than the insulation layer, and a gate electrode filled in the trench.
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Citations
10 Claims
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1. A method for fabricating a transistor, comprising:
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forming a trench in a substrate; forming a polysilicon layer over the substrate and filled in the trench; etching the polysilicon layer in a manner that a portion of the polysilicon layer having a greater thickness over an edge portion of a bottom surface of the trench than over a middle portion of the bottom surface of the trench remains in the trench; oxidizing the entire remaining portion of the polysilicon layer to form an insulation layer over the bottom surface of the trench and forming a gate insulation layer over inner sidewalls of the trench to a smaller thickness than the insulation layer at substantially the same time; and forming a gate electrode over the insulation layer and filled in the trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification