Patent ID: 8501577
Filing Date: 2013-08-06
Classification: H01L

Abstract:
1. A preparation method for a full-isolated silicon on insulator (SOI) substrate with hybrid crystal orientations, comprising: step 1, providing an SOI substrate, wherein the SOI substrate comprises a bottom silicon with a first crystal orientation, an insulating buried layer located on the bottom silicon, and a top silicon with a second crystal orientation and located on the insulating buried layer; step 2: etching the SOI substrate to form a window, wherein the window exposes a part of the bottom silicon, and forming a spacer isolation structure on side walls at periphery of the window; step 3: epitaxially growing a SiGe layer with the first crystal orientation in the window formed with the spacer isolation structure, and continuing to epitaxially grow a top silicon with the first crystal orientation on the SiGe layer; step 4: etching a part of the spacer isolation structure at opposite two sides of the window to expose a part of the bottom silicon, and depositing a supporting material at the position where the part of the spacer isolation structure is etched away, so as to serve as a support for connecting the top silicon with the first crystal orientation and the top silicon with the second crystal orientation; step 5: etching the rest spacer isolation structure, and removing the SiGe layer by adopting a selective etching process, so that the top silicon with the first crystal orientation is suspended; step 6: filling an insulating material below the top silicon with the first crystal orientation to form a second insulating buried layer; and step 7: removing the insulating material and the supporting material at the periphery of the top silicon with the first crystal orientation, fabricating a shallow trench isolation (STI) structure at the periphery of the top silicon with the first crystal orientation, and finally obtaining the full-isolated SOI substrate with hybrid crystal orientations.