Method for manufacturing a semiconductor device with a trench termination
First Claim
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1. A method for manufacturing a semiconductor device comprising:
- providing a semiconductor die of a semiconductive material having a channel receiving layer of a first conductivity;
forming a layer of oxidation retardant material over said channel receiving layer;
removing a portion of said oxidation retardant material to expose said semiconductor die;
etching said exposed semiconductor die to form a termination recess around said oxidation retardant material remaining after said receiving step, said termination recess including a sidewall and a bottom;
forming an oxide on said sidewall and said bottom of said termination recess; and
forming trenches in said channel receiving layer, after forming said oxide on said sidewall and said bottom of said termination recess.
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Abstract
A process for manufacturing a semiconductor device of the trench variety with reduced feature sizes and improved characteristics which process includes forming a termination structure having a field oxide disposed in a recess below the surface of the semiconductor die in which the active elements of the device are formed, and forming source regions after the major thermal steps have been performed.
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Citations
20 Claims
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1. A method for manufacturing a semiconductor device comprising:
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providing a semiconductor die of a semiconductive material having a channel receiving layer of a first conductivity;
forming a layer of oxidation retardant material over said channel receiving layer;
removing a portion of said oxidation retardant material to expose said semiconductor die;
etching said exposed semiconductor die to form a termination recess around said oxidation retardant material remaining after said receiving step, said termination recess including a sidewall and a bottom;
forming an oxide on said sidewall and said bottom of said termination recess; and
forming trenches in said channel receiving layer, after forming said oxide on said sidewall and said bottom of said termination recess. - View Dependent Claims (2, 13, 14, 15)
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3. A method for manufacturing a semiconductor device comprising:
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providing a semiconductor die of a semiconductive material having a channel receiving layer of a first conductivity;
forming a layer of oxidation retardant material over said channel receiving layer;
forming trenches in said channel receiving layer in one region of said channel receiving layer;
forming a termination recess around said trenches said termination recess having exposed surfaces of semiconductive material;
forming another layer of oxidation retardant material over sidewalls and bottom of each of said trenches;
growing an oxide layer on exposed surfaces of said termination recess;
implanting channel dopants of a second conductivity in said channel receiving layer before forming said layer of oxidation retardant material; and
diffusing said channel dopants after forming said layer of oxidation retardant material to form a channel region;
removing oxidation retardant material from bottoms of said trenches leaving oxidation retardant material on said sidewalls of said trenches;
forming a bottom oxide layer at said bottom of said trenches;
removing said oxidation retardant material from said sidewalls of said trenches; and
forming a layer of gate oxide on said sidewalls of said trenches;
wherein said bottom oxide layer is thicker than said gate oxide layer. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12)
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16. A method for manufacturing a MOSgated semiconductor switching device, comprising:
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providing a semiconductor die having a channel receiving region of first conductivity;
forming a channel region of second conductivity in said channel receiving region;
forming at least one trench in said semiconductor die extending through said channel region;
forming a gate structure in said at least one trench; and
forming a conductive region of said first conductivity type adjacent each side of said trench in said channel region after forming said gate structure; and
forming a low temperature oxide body over all of said gate structure, and at least a portion of said conductive region; and
forming recesses on a top portion of said low temperature oxide body. - View Dependent Claims (17, 18, 19, 20)
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Specification