Patent ID: 6774017
Filing Date: 2004-08-10
Classification: H01L

Abstract:
A method for forming a semiconductor structure, comprising the steps of:providing a substrate comprising a first surface; forming a continuous buried oxide layer within the substrate, wherein the buried oxide layer comprises a first portion and a second portion, wherein the first portion of the buried oxide layer has an upper boundary at a depth H1 below a point on the first surface and a lower boundary at a depth H3 below the point on the first surface, wherein the second portion of the buried oxide layer has an upper boundary at a depth H2 below the point on the first surface and a lower boundary at a depth H4 below the point on the first surface, wherein H3>H1, wherein H4>H2, wherein H2>H1, and wherein H4>H3; and after forming the buried oxide layer, forming a first trench isolation and a second trench isolation, wherein the first trench isolation has an upper boundary that touches and is coplanar with the first surface and a lower boundary that is located between the first surface and the first portion of the buried oxide layer, and wherein the second trench isolation has an upper boundary that touches and is coplanar with the first surface and a lower boundary that is located between the first surface and the second portion of the buried oxide layer, wherein the first trench isolation consists of one segment, wherein the second trench isolation includes two segments, and wherein the second trench isolation touches the second portion of the buried oxide layer.