Power MOSFET and method for forming same using a self-aligned body implant
First Claim
Patent Images
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 source regions in the semiconductor layer adjacent the outwardly extending dielectric layer;
forming spacers laterally adjacent the outwardly extending upper portion of the dielectric layer after forming the source regions;
using the spacers as a self-aligned mask for forming source/body contact regions in the semiconductor layer so that the source/body contacts regions are below the source regions;
forming a source electrode on the source regions and on the dielectric layer; and
forming at least one conductive via between the source electrode and the source/body contact regions.
1 Assignment
0 Petitions
Accused Products
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.
-
Citations
14 Claims
-
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 source regions in the semiconductor layer adjacent the outwardly extending dielectric layer; forming spacers laterally adjacent the outwardly extending upper portion of the dielectric layer after forming the source regions; using the spacers as a self-aligned mask for forming source/body contact regions in the semiconductor layer so that the source/body contacts regions are below the source regions; forming a source electrode on the source regions and on the dielectric layer; and forming at least one conductive via between the source electrode and the source/body contact regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. 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 after forming the source regions; using the spacers as a self-aligned mask for etching the semiconductor layer not covered by the spacers; using the spacers as a self-aligned mask for implanting dopants for defining source/body contact regions in the semiconductor layer so that the source/body contacts regions are below the source regions; forming a source electrode on the source regions and on the dielectric layer; and forming at least one conductive via between the source electrode and the source/body contact regions. - View Dependent Claims (10, 11, 12, 13, 14)
-
Specification