Patent ID: 6696348
Filing Date: 2004-02-24
Classification: H01L

Abstract:
A method of forming a semiconductor device comprising:forming a SiGe layer on a silicon-containing semiconductor substrate; forming a silicon layer over the SiGe layer; forming a layer of a first insulating material on the SiGe layer; forming a layer of a second insulating material on the first insulating material layer; forming a trench of a first width in the layer of first insulating material and the layer of the second insulating material; extending said trench into the silicon layer in both the lateral and vertical directions, so that the trench undercuts the layer of first insulating material; further extending the trench formed in the first and second insulating material layers into the SiGe layer such that a portion of the trench extending into the SiGe layer has substantially the same width as said first width; and filling the trench with an insulating material.