FORMATION OF IMPROVED SOI SUBSTRATES USING BULK SEMICONDUCTOR WAFERS

摘要

The present invention relates to semiconductor-on-insulator (SOI) substrates having device regions (2, 4, 6), each comprises a base semiconductor substrate layer (12) and a semiconductor device layer (16) and a buried insulator layer (14) between. The semiconductor device layer (16) supported by vertical insulating pillars (22), each having a ledge extending between the base semiconductor substrate layer (12) and the semiconductor device layer (16). The SOI substrates of the present invention can be readily formed from a precursor substrate structure with a "floating" semiconductor device layer that is spaced apart from the base semiconductor substrate layer by an air gap (15) and is supported by the vertical insulating pillars (22). The air gap (15) is preferably formed by selective removal of a sacrificial layer (13) located between the base semiconductor substrate layer (12) and the semiconductor device layer (16).