Subground rule sti fill for hot structure

Abstract

This invention provides a hybrid orientation (HOT) semiconductor-on-insulator (SOI) structure having an isolation region, e.g. a shallow trench isolation region (STI), and a method for forming the STI structure that is easy to control. The method of forming the isolation region includes an etch of the insulating material, selective to the semiconductor material, followed by an etch of the semiconductor material, selective to the insulating material, and then filling any high aspect ratio gaps with a CVD oxide, and filling the remainder of the STI with an HDP oxide.

1 . A semiconductor structure comprising:
 a semiconductor on insulator (SOI) region comprising a first semiconductor material on a buried insulating layer;   an isolation region; and   a bulk semiconductor region comprising a second semiconductor material, wherein said bulk semiconductor region is separated from said SOI region by said isolation region,   wherein said isolation region comprises an insulating spacer disposed on a sidewall of said buried insulating layer, and a high aspect ratio gap between said insulating spacer and said second semiconductor material, wherein said high aspect ratio gap is filled with a CVD oxide.   
   
   
       2 . A semiconductor structure of  claim 1 , wherein said first semiconductor material has a first crystallographic orientation and said second semiconductor material has a second crystallographic orientation different from said first crystallographic orientation. 
   
   
       3 . The semiconductor structure of  claim 1 , further comprising a semiconductor device of a first type on said first semiconductor material and a semiconductor device of a second type on said second semiconductor material. 
   
   
       4 . The semiconductor structure of  claim 2 , further comprising a semiconductor device of a first type on said first semiconductor material and a semiconductor device of a second type on said second semiconductor material. 
   
   
       5 . The semiconductor structure of  claim 1 , wherein said insulation region further comprises an HDP oxide. 
   
   
       6 . The semiconductor structure of  claim 1 , wherein said high aspect ratio gap has an aspect ratio equal to or greater than or equal to 3:1. 
   
   
       7 . The semiconductor structure of  claim 1 , wherein said insulating spacer has a height substantially similar to the thickness of said buried insulating layer. 
   
   
       8 . The semiconductor structure of  claim 1 , wherein said insulating spacer has a height within about ±20 nm of the thickness of said buried insulating layer. 
   
   
       9 . The semiconductor structure of  claim 1 , wherein said insulating spacer comprises an oxide. 
   
   
       10 . A semiconductor structure comprising:
 a semiconductor on insulator (SOI) region comprising a first semiconductor material on a buried oxide layer;   an isolation region; and   a bulk semiconductor region comprising a second semiconductor material, wherein said bulk semiconductor region is separated from said SOI region by said isolation region,   wherein said isolation region comprises an oxide spacer disposed on a sidewall of said buried oxide layer, and a high aspect ratio gap between said oxide spacer and said second semiconductor material, wherein said high aspect ratio gap is filled with a CVD oxide.   
   
   
       11 . The semiconductor structure of  claim 10 , wherein said first semiconductor material has a first crystallographic orientation and said second semiconductor material has a second crystallographic orientation different than said first crystallographic orientation. 
   
   
       12 . The semiconductor structure of  claim 10 , wherein said high aspect ratio gap has an aspect ratio equal to or greater than about 3:1. 
   
   
       13 . The semiconductor structure of  claim 10 , wherein said isolation region further comprises an HDP oxide. 
   
   
       14 . The semiconductor structure of  claim 10 , further comprising a semiconductor device of a first type on said first semiconductor material and a semiconductor device of a second type on said second semiconductor material. 
   
   
       15 . The semiconductor structure of  claim 11 , further comprising a semiconductor device of a first type on said first semiconductor material and a semiconductor device of a second type on said second semiconductor material.