Method for forming isolation regions in a semiconductor device

摘要

A process for fabricating isolation regions in a semiconductor substrate which does not depend upon pattern definition capability. In one embodiment a device isolation region (30) is formed in a semiconductor substrate (12) by first creating a trench (18) in the substrate (12). A single-crystal SiGe layer (24) is formed to overlie the wall surface (20) of the trench (18). A layer of selectively-deposited, single-crystal silicon (26) is formed in the trench (18) using both the bottom surface (22) of the trench (18) and the SiGe layer (24) as a nucleation site for the selective deposition process. After the single-crystal silicon layer (26) is formed, the SiGe layer (24) is selectively removed and the previously occupied space is filled with a dielectric material to form isolation region (30).