Power mosfet and method for forming same using a self-aligned body implant
First Claim
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1. A method for making a MOSFET comprising:
- 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;
forming a dielectric layer to fill an upper portion of the trench;
removing portions of the semiconductor layer laterally adjacent the dielectric layer so that an upper portion thereof extends outwardly from the semiconductor layer;
forming spacers laterally adjacent the outwardly extending upper portion of the dielectric layer; and
using the spacers as a self-aligned mask for defining source/body contact regions.
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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.
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Citations
23 Claims
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1. A method for making a MOSFET comprising:
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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;
forming a dielectric layer to fill an upper portion of the trench;
removing portions of the semiconductor layer laterally adjacent the dielectric layer so that an upper portion thereof extends outwardly from the semiconductor layer;
forming spacers laterally adjacent the outwardly extending upper portion of the dielectric layer; and
using the spacers as a self-aligned mask for defining source/body contact regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for making a MOSFET comprising:
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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;
forming a dielectric layer to fill an upper portion of the trench;
removing portions of the semiconductor layer laterally adjacent the dielectric layer so that an upper portion thereof extends outwardly from the semiconductor layer;
forming spacers laterally adjacent the outwardly extending upper portion of the dielectric layer;
using the spacers as a self-aligned mask for etching the semiconductor layer not covered by the spacers; and
using the spacers as a self-aligned mask for implanting dopants for defining source/body contact regions. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23-31. -31. (canceled)
Specification