Patent ID: 7439108

Claim:
A method of semiconductor device manufacturing, comprising: providing a substrate; and forming a first silicon-on-insulator (SOI) region having a first crystal orientation, a second SOI region having a second crystal orientation and a third SOI region having a third crystal orientation on the substrate, wherein: the first, second and third SOI regions are coplanar; providing the substrate includes providing a substrate including a bulk substrate layer having the first crystal orientation below a silicon-on-insulator (SOI) layer having the second crystal orientation below an SOI layer having the third crystal orientation; and forming a first SOI region having the first crystal orientation, a second SOI region having the second crystal orientation and a third SOI region having the third crystal orientation on the substrate includes: selectively etching one or more portions of the substrate to the SOI layer having the second crystal orientation; selectively etching one or more portions of the substrate to the bulk substrate layer having the first crystal orientation; and forming oxide spacers on sidewalls exposed by selectively etching one or more portions of the substrate to the SOI layer having the second crystal orientation and selectively etching one or more portions of the substrate to the bulk substrate layer.