Method of manufacturing a closed cell trench MOSFET
First Claim
1. A method of fabrication a closed cell trench metal-oxide-semiconductor field effect transistor (TMOSFET) comprising:
- depositing a first semiconductor layer upon a substrate, wherein said first semiconductor layer is doped with a first type of impurity;
etching a plurality of trenches in said first semiconductor layer, wherein a first set of said plurality of trenches are substantially parallel with respect to each other and a second set of said plurality of trenches are substantially normal-to-parallel with respect to said first set of said plurality of trenches;
forming a dielectric proximate said plurality of trenches;
doping said first semiconductor layer proximate the bottoms of said first set of said plurality of trenches;
depositing a second semiconductor layer in said plurality of trenches;
doping a first portion of said first semiconductor layer with a second type of impurity; and
doping a second portion of said first semiconductor layer proximate said dielectric with said first type of impurity.
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Accused Products
Abstract
Embodiments of the present invention provide an improved closed cell trench metal-oxide-semiconductor field effect transistor (TMOSFET). The closed cell TMOSFET comprises a drain, a body region disposed above the drain region, a gate region disposed in the body region, a gate insulator region, a plurality of source regions disposed at the surface of the body region proximate to the periphery of the gate insulator region. A first portion of the gate region and the gate oxide region are formed as parallel elongated structures. A second portion of the gate region and the oxide region are formed as normal-to-parallel elongated structures. A portion of the gate and drain overlap region are selectively blocked by the body region, resulting in lower overall gate to drain capacitance.
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Citations
20 Claims
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1. A method of fabrication a closed cell trench metal-oxide-semiconductor field effect transistor (TMOSFET) comprising:
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depositing a first semiconductor layer upon a substrate, wherein said first semiconductor layer is doped with a first type of impurity;
etching a plurality of trenches in said first semiconductor layer, wherein a first set of said plurality of trenches are substantially parallel with respect to each other and a second set of said plurality of trenches are substantially normal-to-parallel with respect to said first set of said plurality of trenches;
forming a dielectric proximate said plurality of trenches;
doping said first semiconductor layer proximate the bottoms of said first set of said plurality of trenches;
depositing a second semiconductor layer in said plurality of trenches;
doping a first portion of said first semiconductor layer with a second type of impurity; and
doping a second portion of said first semiconductor layer proximate said dielectric with said first type of impurity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of fabrication a closed cell trench metal-oxide semiconductor field effect transistor (TMOSFEET) comprising:
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depositing a first portion of a first semiconductor layer upon a substrate, wherein said first semiconductor layer is doped with a first type of impurity;
doping said first portion of said first semiconductor layer, wherein a plurality of buried doped regions are formed in said first portion of said first semiconductor layer;
depositing a second portion of said first semiconductor layer upon said first portion of said first semiconductor layer;
etching a plurality of trenches in said first semiconductor layer, wherein a first set of said plurality of trenches are substantially parallel with respect to each other and aligned to said plurality of buried doped regions and wherein a second set of said plurality of trenches are substantially normal-to-parallel with respect to said first set of said plurality of trenches;
forming a dielectric proximate said plurality of trenches;
depositing a second semiconductor layer in said plurality of trenches;
doping a body region of said first semiconductor layer between said plurality of trenches with a second type of impurity; and
doping a source region of said first semiconductor layer between said plurality of trenches and said first region of said first semiconductor layer. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification