Patent ID: 6919258

Claim:
A method of forming an isolation structure in a semiconductor, comprising: providing a single crystal substrate; forming a first dielectric overlying the substrate; forming a second dielectric overlying the first dielectric, the second dielectric being a different material than the first dielectric; forming a first opening having a first diameter completely through the first dielectric and forming a second opening having a second diameter completely through the second dielectric, the second diameter being greater than the first diameter wherein the first opening and the second opening expose a surface of the single crystal substrate; filling the first opening and a portion of the second opening with a first single crystal semiconductor material having a relaxed state by having defects for a controlled depth from the single crystal substrate to a predetermined height, a remainder of the first single crystal semiconductor material not having defects; filling a remaining portion of the second opening with a second single crystal semiconductor material that is strained by having a predetermined thickness that does not exceed a critical thickness where defects begin to form; and forming a transistor overlying and within at least a portion of the second opening.