Method of making cavities in a semiconductor wafer

Abstract

The invention provides a method of making a semiconductor structure that includes a surface layer of silicon, a buried insulating layer, and a substrate. The method includes implanting atoms through at least a portion of the insulating layer; and etching the insulating layer in at least a portion of the layer through which atoms have been implanted.

1 . A semiconductor structure comprising a supporting substrate that includes: 
 a surface layer of a first material;    a sub-surface layer of a second material; and    a selected zone in both the surface layer and at least a portion of the sub-surface layer in which atoms have been implanted.    
   
   
       2 . The semiconductor structure of  claim 1 , wherein the selected atom-implanted zone has a concave, convex, or polygonal shape in a plane parallel to that of the sub-surface layer.  
   
   
       3 . The semiconductor structure of  claim 1 , wherein the second material is more susceptible to etching than the first material.  
   
   
       4 . The semiconductor structure of  claim 1 , wherein the first material is a semiconductor material and the second material has properties sufficient to electrically insulate the first material so that the sub-surface layer is an insulating layer.  
   
   
       5 . The semiconductor structure of  claim 4 , wherein the first material of the surface layer is silicon and the implanted atoms are ions of hydrogen or ions of helium.  
   
   
       6 . A silicon semiconductor structure comprising a silicon substrate that includes: 
 a surface layer of a first material;    a sub-surface layer of a second material; and    a selected zone of predetermined shape in the surface layer in which atoms have been implanted and a cavity formed in at least a portion of the sub-surface layer.    
   
   
       7 . The semiconductor structure of  claim 6 , wherein the cavity has a shape that does not extend beyond or is essentially the same as that of the selected zone.  
   
   
       8 . The semiconductor structure of  claim 6 , in which at least a portion of the cavity extends beyond the shape of the selected zone and into a portion of the sub-surface layer which is not implanted with atoms.  
   
   
       9 . The semiconductor structure of  claim 6 , wherein the cavity has a cylindrical, or semi-cylindrical, square or rectangular shape.  
   
   
       10 . The semiconductor structure of  claim 6 , wherein the cavity is elliptical, partially elliptical, polygonal or partially polygonal in shape.  
   
   
       11 . A semiconductor structure comprising a silicon substrate that includes: 
 a surface layer of a first material;    a sub-surface layer of a second material; and    a selected zone of predetermined shape in the surface layer in which atoms have been implanted and a cavity formed in at least a portion of the sub-surface layer;    wherein the cavity includes a first zone having a first maximum dimension, and a second zone having a second maximum dimension, with the second maximum dimension being different from the first.    
   
   
       12 . The semiconductor structure of  claim 11 , wherein the first and second zones of the cavity are situated at different mean depths in the sub-surface layer.