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.
36 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