SOI substrate

Abstract

An SOI substrate having a partial SOI structure in which a buried insulating film having a predetermined area is formed via an active layer in a part of a silicon single crystal substrate in plan view by ion-implanting elements to the part of the substrate and then applying thereto a thermal processing, wherein a thickness of a peripheral edge portion of said buried insulating film is getting thinner toward a terminal edge of said buried insulating film.

1 . An SOI substrate having a partial SOI structure in which a buried insulating film having a predetermined area is formed via an active layer in one part of a silicon single crystal substrate in plan view, wherein 
 a thickness of a peripheral edge portion of said buried insulating film is getting thinner toward a terminal edge of said buried insulating film.    
   
   
       2 . An SOI substrate in accordance with  claim 1 , in which a shape of said buried insulating film is circular, elliptic or polygonal shape in plan view.  
   
   
       3 . An SOI substrate in accordance with  claim 1 , in which a width of said peripheral edge portion having reduced thickness of said buried insulating film is in a range of 10 nm to 1000 nm.  
   
   
       4 . An SOI substrate in accordance with  claim 3 , in which a shape of said buried insulating film is circular, elliptic or polygonal shape in plan view.