Patent ID: 7507643
Filing Date: 2009-03-24
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor substrate, comprising; forming a first semiconductor layer on a semiconductor base; forming a second semiconductor layer having a lower etching selection ratio than the first semiconductor layer on the first semiconductor layer; removing a part of the second semiconductor layer and a part of the first semiconductor layer around an element region so as to form a recess for a support, the recess exposing the semiconductor base; forming a support forming layer on the semiconductor base so as to fill the recess and cover the second semiconductor layer; etching a part of the support forming layer and the first and second semiconductor layers excluding portions corresponding to the recess and the element region so as to form a support and an exposed face exposing a part of an end face of the first semiconductor layer and a part of an end face of the second semiconductor layer located under the support; etching the first semiconductor layer through the exposed face so as to form a cavity between the second semiconductor layer and the semiconductor base; forming a buried insulating layer in the cavity; and planarizing a top surface of the second semiconductor layer so as to remove a part of the support located on the second semiconductor layer, wherein the recess is formed in a single-crystalline epitaxial region on the semiconductor base.