Patent ID: 7394144

Claim:
A method of manufacturing a semiconductor device, comprising: (a) providing a silicon semiconductor body having opposed first and second major surfaces having a lower-doped region at the first major surface above a higher doped region, the lower-doped region and the higher doped region both being doped to have a first conductivity type, the lower-doped region having a lower doping than the higher doped region; (b) defining a mask having openings on the first major surface; (c) forming trenches through the openings in the mask, the trenches extending from the first major surface towards the second major surface through the lower-doped region towards the higher doped region; (d) depositing a trench insulating layer on the sidewalls and base of the trenches as well as the first major surface; (e) removing the trench insulating layer from the top of the sidewalls of the trenches adjacent to the first major surface leaving exposed silicon at the top of the sidewalls of the trench; and (f) growing silicon selectively on the exposed silicon to grow silicon at the top of the trenches and plugging the top of the trenches, wherein the method further includes defining a structure for depleting the lower-doped region in an operating state of the semiconductor device to allow the lower-doped region to support a voltage in that operating state.