Patent ID: 8859389
Filing Date: 2014-10-14
Classification: H01L

Abstract:
1. A method of forming fins, comprising: forming a multi-layer structure over a semiconductor substrate, the multi-layer structure comprises a silicon-germanium layer as a first layer over the semiconductor substrate, a silicon layer as a second layer over the first layer, and a third layer over the second layer wherein the silicon layer is electrically in contact with the semiconductor substrate via the silicon-germanium layer; removing upper portions of the semiconductor substrate and portions of the multi-layer structure to form fins of the semiconductor substrate and portions of the multi-layer structure; selectively oxidizing the silicon-germanium layer while oxidization of the second layer is less than the oxidization of the first layer, wherein the silicon-germanium layer is turned into a SiGeOxide layer and wherein the silicon layer is electrically separated from the semiconductor substrate by the SiGeOxide layer; filling gaps between the fins with an insulating material after the selectively oxidizing; and recessing at least a portion of the insulating material to expose a fin, wherein at least a side surface of the second layer or a top surface of the fin is exposed, and at least a part of side surfaces of the SiGeOxide layer is uncovered from the recessed insulating material.