Power MOSFET and method for forming same using a self-aligned body implant
First Claim
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1. A MOSFET comprising:
- a semiconductor layer having a trench therein;
a gate conducting layer in a lower portion of said trench;
a dielectric layer in an upper portion of said trench;
source regions adjacent said dielectric layer; and
source/body contact regions laterally spaced apart from said trench and being recessed within said semiconductor layer and non-interruptively contacting said source regions;
said dielectric layer extending outwardly from said semiconductor layer, said source regions and said source/body contact regions, and said outwardly extending dielectric layer having sidewalls aligned with sidewalls of said trench.
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Abstract
A method for making a power MOSFET includes forming a trench in a semiconductor layer, forming a gate dielectric layer lining the trench, forming a gate conducting layer in a lower portion of the trench, and forming a dielectric layer to fill an upper portion of the trench. Portions of the semiconductor layer laterally adjacent the dielectric layer are removed so that an upper portion thereof extends outwardly from the semiconductor layer. Spacers are formed laterally adjacent the outwardly extending upper portion of the dielectric layer, the spacers are used as a self-aligned mask for defining source/body contact regions.
67 Citations
16 Claims
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1. A MOSFET comprising:
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a semiconductor layer having a trench therein;
a gate conducting layer in a lower portion of said trench;
a dielectric layer in an upper portion of said trench;
source regions adjacent said dielectric layer; and
source/body contact regions laterally spaced apart from said trench and being recessed within said semiconductor layer and non-interruptively contacting said source regions;
said dielectric layer extending outwardly from said semiconductor layer, said source regions and said source/body contact regions, and said outwardly extending dielectric layer having sidewalls aligned with sidewalls of said trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A MOSFET comprising:
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a semiconductor layer having a trench therein;
a gate dielectric layer lining said trench;
a gate conducting layer in a lower portion of said trench;
a dielectric layer in an upper portion of said trench;
source regions adjacent said dielectric layer;
source/body contact regions laterally spaced from said gate conducting layer and non-interruptively contacting said source regions;
said dielectric layer extending outwardly from said semiconductor layer, said source regions and said source/body contact regions, and said outwardly extending dielectric layer having sidewalls aligned with sidewalls of said trench;
a source electrode on said source regions and on said dielectric layer; and
at least one conductive via between said source electrode and said source/body contact regions and extending through said source regions. - View Dependent Claims (10, 11, 12)
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13. A MOSFET comprising:
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a semiconductor layer having a trench therein;
a gate dielectric layer lining said trench;
a gate conducting layer in a lower portion of said trench;
a dielectric layer in an upper portion of said trench and extending outwardly from said semiconductor layer;
source regions adjacent said dielectric layer and including an opening therein; and
source/body contact regions laterally spaced from said gate conducting layer and non-interruptively contacting said source regions, said source/body contact regions being exposed by the opening in said source regions;
said dielectric layer extending outwardly from said semiconductor layer, said source regions and said source/body contact regions, and said outwardly extending dielectric layer having sidewalls aligned with sidewalls of said trench. - View Dependent Claims (14, 15, 16)
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Specification