Patent ID: 7790528
Filing Date: 2010-09-07
Classification: H01L

Abstract:
1. A method for fabricating a semiconductor structure, comprising: providing a first semiconductor layer having a first crystal orientation and a second semiconductor layer over at least part of the first semiconductor layer, where the second semiconductor layer has a second crystal orientation and is electrically isolated from the first semiconductor layer by an insulator layer; forming a trench opening by selectively removing a portion of the second semiconductor layer to expose the insulator layer in a first region and to leave a remaining portion of the second semiconductor layer in a second region; thermally growing silicon dioxide on an exposed sidewall of the second semiconductor layer, thereby forming a sidewall oxide spacer by consuming part of the second semiconductor layer at the exposed sidewall; extending the trench opening by selectively removing the insulator layer in the first region to trim the sidewall oxide spacer and expose the first semiconductor layer, thereby leaving a portion of the sidewall oxide spacer to protect the remaining portion of the second semiconductor layer against epitaxial growth; and filling at least part of the trench opening by epitaxially growing a first epitaxial semiconductor material on at least an exposed surface of the first semiconductor layer to form a first epitaxial semiconductor layer in the trench opening that has a third crystal orientation that is the same as the first crystal orientation.