Trench power MOSFET with reduced gate resistance
First Claim
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1. A method for manufacturing a power semiconductor device comprising:
- forming a mask layer over a first surface of a semiconductor body;
patterning said mask layer with a plurality of openings each opening extending to and exposing said first surface of said semiconductor body at the bottom thereof;
etching a termination trench in said semiconductor body prior to patterning said mask layer, said termination trench including a side wall and bottom, extending to a depth below a first depth and defining an active area that includes said trenches;
defining trenches in said semiconductor body by etching said semiconductor body through said openings, each trench including sidewalls and a bottom;
forming an insulation layer on said sidewalls of said trenches;
forming a gate electrode in each of said trenches, each gate electrode including a free end extending above said first surface into a respective opening in said mask layer to a height substantially co-planar with a top surface of said mask layer;
siliciding each of said gate electrodes at its free end;
removing said mask layer, whereby each gate electrode becomes proud and extends above said first surface of said semiconductor body;
implanting continuous source implant regions of first conductivity in said semiconductor body between said trenches;
forming spaced insulation interlayers over said free ends of said gate electrodes;
etching through said source implant regions;
implanting regions of second conductivity into said semiconductor body through spaces between said spaced interlayers to form implant regions of said second conductivity; and
applying a diffusion drive to form source regions and high conductivity contact regions of said second conductivity.
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Abstract
A method for manufacturing a trench type power semiconductor device which includes process steps for forming proud gate electrodes in order to decrease the resistivity thereof.
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Citations
7 Claims
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1. A method for manufacturing a power semiconductor device comprising:
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forming a mask layer over a first surface of a semiconductor body; patterning said mask layer with a plurality of openings each opening extending to and exposing said first surface of said semiconductor body at the bottom thereof; etching a termination trench in said semiconductor body prior to patterning said mask layer, said termination trench including a side wall and bottom, extending to a depth below a first depth and defining an active area that includes said trenches; defining trenches in said semiconductor body by etching said semiconductor body through said openings, each trench including sidewalls and a bottom; forming an insulation layer on said sidewalls of said trenches; forming a gate electrode in each of said trenches, each gate electrode including a free end extending above said first surface into a respective opening in said mask layer to a height substantially co-planar with a top surface of said mask layer; siliciding each of said gate electrodes at its free end; removing said mask layer, whereby each gate electrode becomes proud and extends above said first surface of said semiconductor body; implanting continuous source implant regions of first conductivity in said semiconductor body between said trenches; forming spaced insulation interlayers over said free ends of said gate electrodes; etching through said source implant regions; implanting regions of second conductivity into said semiconductor body through spaces between said spaced interlayers to form implant regions of said second conductivity; and applying a diffusion drive to form source regions and high conductivity contact regions of said second conductivity. - View Dependent Claims (2, 3, 4, 5)
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6. A method for manufacturing a power semiconductor device comprising:
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forming a mask layer over a first surface of a semiconductor body; patterning said mask layer with a plurality of openings each opening extending to and exposing said first surface of said semiconductor body at the bottom thereof; defining trenches in said semiconductor body by etching said semiconductor body through said openings, each trench including sidewalls and a bottom; forming an insulation layer on said sidewalls of said trenches; forming a gate electrode in each of said trenches, each gate electrode including a free end extending above said first surface into a respective opening in said mask layer to a height substantially co-planar with a top surface of said mask layer; siliciding each of said gate electrodes at its free end; removing said mask layer, whereby each gate electrode becomes proud and extends above said first surface of said semiconductor body; implanting continuous source implant regions of first conductivity in said semiconductor body between said trenches; forming spaced insulation interlayers over said free ends of said gate electrodes; etching through said source implant regions; implanting regions of second conductivity into said semiconductor body through spaces between said spaced interlayers to form implant regions of said second conductivity; and applying a diffusion drive to form source regions and high conductivity contact regions of said second conductivity;
forming a channel region of a second conductivity in said semiconductor body to a first depth within said semiconductor body, said trenches extending to a depth below said first depth; and
etching a termination trench in said semiconductor body prior to patterning said mask layer, said termination trench including a side wall and bottom, extending to a depth below said first depth and defining an active area that includes said trenches;
forming a field insulation body over said sidewall and said bottom of said termination trench;
forming an electrically conductive layer over said field insulation and said mask layer; and
etching said electrically conductive layer that overlies said mask layer to define a termination electrode in said termination trench. - View Dependent Claims (7)
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Specification