Trench MOSFET superjunction structure and method to manufacture
First Claim
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1. A semiconductor device comprising:
- a semiconductor region of first conductivity formed over a semiconductor substrate of said first conductivity;
a semiconductor trench receiving region formed over said semiconductor region of said first conductivity;
a plurality of trenches formed in said trench receiving region, each trench including a bottom surface and opposing sidewalls;
a channel region of a second conductivity adjacent said trenches;
a conductive column of said first conductivity formed between the bottom surface of each trench and said semiconductor region of said first conductivity;
a charge-balanced region of said second conductivity formed adjacent each conductive column and adjacent said channel region;
conductive regions of said first conductivity formed adjacent each trench and in said channel region;
a gate insulation layer formed at least on said sidewalls of said trenches;
a gate electrode formed in each of said trenches; and
an electrical contact layer formed over said trench receiving region and in contact with said conductive regions of said first conductivity.
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Abstract
A power semiconductor device including a plurality of trenches each for supporting a gate structure adjacent a channel region, and a plurality of drain columns each under the bottom of each trench, and each formed by multiple high energy implants.
26 Citations
17 Claims
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1. A semiconductor device comprising:
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a semiconductor region of first conductivity formed over a semiconductor substrate of said first conductivity;
a semiconductor trench receiving region formed over said semiconductor region of said first conductivity;
a plurality of trenches formed in said trench receiving region, each trench including a bottom surface and opposing sidewalls;
a channel region of a second conductivity adjacent said trenches;
a conductive column of said first conductivity formed between the bottom surface of each trench and said semiconductor region of said first conductivity;
a charge-balanced region of said second conductivity formed adjacent each conductive column and adjacent said channel region;
conductive regions of said first conductivity formed adjacent each trench and in said channel region;
a gate insulation layer formed at least on said sidewalls of said trenches;
a gate electrode formed in each of said trenches; and
an electrical contact layer formed over said trench receiving region and in contact with said conductive regions of said first conductivity. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor device comprising:
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an epitaxially formed drain region of a first conductivity formed over a semiconductor substrate of the same conductivity;
a trench receiving region;
a plurality of trenches formed in said trench receiving region, each trench including a bottom surface and opposing sidewalls;
a channel region of a second conductivity adjacent said trenches;
source regions of a first conductivity formed in said trench receiving region adjacent said trenches;
a plurality of columns of said first conductivity each formed directly below a respective trench and extending between the bottom of said trench to said drain region, each column being spaced from another column by a charge-balanced region of said second conductivity;
a gate insulation layer formed at least on said sidewalls of said trenches;
a gate electrode formed in each of said trenches; and
a source contact layer formed over said trench receiving region and in contact with said source regions. - View Dependent Claims (9, 10, 11, 12)
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13. A method for manufacturing a semiconductor device comprising:
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providing a trench receiving semiconductor layer of a first conductivity;
forming a mask over said trench receiving semiconductor layer, said mask including openings, each opening terminating at said trench receiving semiconductor layer at its bottom;
forming a trench in said trench receiving layer at said bottom of each of said openings in said mask;
leaving said mask in place;
sequentially implanting dopants of said second conductivity through the bottom of said trench at a plurality of different depths to form a plurality of implant regions below the bottom of said trench;
forming a column of said second conductivity below said trench by applying a diffusion drive so that dopants at each of said plurality of implant regions diffuses to reach at least the dopants of an adjacent implant region. - View Dependent Claims (14, 15, 16, 17)
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Specification