US Patent 7468538 Strained silicon on a SiGe on SOI substrate

An intermediate semiconductor structure is disclosed. The semiconductor structure includes a substrate; a relaxed Si1-xGex layer on the substrate, the relaxed Si1-xGex layer having at least one trench; an un-etched Si layer portion on the substrate and beneath the relaxed Si1-xGex layer along a periphery of the substrate providing structural support for the relaxed Si1-xGex layer along the periphery of the substrate; and at least one void between the relaxed Si1-xGex layer and the substrate, wherein the void encompasses an entire surface area of the substrate but for a portion of the substrate in contact with the un-etched Si layer portion.