Patent ID: 7033889
Filing Date: 2006-04-25
Classification: H01L

Abstract:
1. A method of forming a semiconductor device including an insulated trench electrode in a trench, the trench extending through a semiconductor body portion of the device, and the trench electrode being dielectrically coupled to the body portion by an insulating layer at a side-wall of the trench, the method including the steps of: (a) etching a trench into the body portion; (b) providing a layer of filler material over the bottom of the trench; (c) providing trench electrode material in the trench with a path defined through the trench electrode material to the underlying filler material; (d) etching to remove filler material between the trench electrode material and the bottom of the trench; and (e) closing the path through the trench electrode material to leave a cavity between the trench electrode material and the bottom of the trench, which cavity reduces the dielectric coupling between the trench electrode and the body portion at the bottom of the trench.