Bonded soi substrate, and method for manufacturing the same

Abstract

This bonded SOI substrate includes: an SOI layer having a low density impurity layer in which dopants are present at low density and a high density impurity layer in which dopants are present at high density; a wafer for a support substrate which supports said SOI layer; and a buried insulating film, wherein said SOI layer and said wafer for a support substrate are bonded with said buried insulating film therebetween, and gettering sites are formed in said high density impurity layer.

1 .- 7 . (canceled) 
     
     
         8 . A method for manufacturing a bonded SOI substrate, comprising:
 a step of forming a high density impurity layer which includes dopants at high density in a surface side of a wafer for an active layer which includes dopants at low density;   a step of generating dislocations or stacking faults in a vicinity of a surface of said high density impurity layer in said wafer for an active layer; and   a bonding step of bonding said wafer for an active layer and a wafer for a support substrate which supports said wafer for an active layer with a buried insulating film therebetween.   
     
     
         9 . A method for manufacturing a bonded SOI substrate according to  claim 8 , wherein an insulating film as said buried insulating film is formed only in said wafer for a support substrate. 
     
     
         10 . A method for manufacturing a bonded SOI substrate, comprising:
 an ion implanting step of implanting dopants in a surface side of a wafer for an active layer in which dopants are present at low density so as to form an ion implantation layer;   a heat-treating step of heat-treating said wafer for an active layer after said ion implantation, thereby making said ion implantation layer be a high density impurity layer along with forming an oxide film in an ion implanted surface of said wafer for an active layer so as to generate dislocations or stacking faults in a vicinity of a surface of said high density impurity layer;   an oxide film removing step of removing said oxide film; and   a bonding step of bonding said wafer for an active layer and a wafer for a support substrate which supports said wafer for an active layer with a buried insulating film therebetween.   
     
     
         11 . A method for manufacturing a bonded SOI substrate according to  claim 10 , wherein an insulating film as said, buried insulating film is formed only in said wafer for a support substrate. 
     
     
         12 . A method for manufacturing a bonded SOI substrate, comprising:
 a step of implanting dopants into a wafer for an active layer which is non-doped or in which dopants are present at low density from a surface of said wafer for an active layer;   a step of heat-treating said wafer for an active layer in an oxygen atmosphere after said ion implantation, thereby forming an oxide film in said surface of said wafer for an active layer along with diffusing said implanted dopants thermally;   a step of, after said ion implantation, bonding said wafer for an active layer and a wafer for a support substrate in a state such that a surface in which said oxide film is formed be a bonded surface so as to make said oxide film intervening between both wafers be a buried oxide film;   a step of, after said bonding, heat-treating for bonding so as to strengthen bonding between said wafer for an active layer and said wafer for a support substrate; and   a step of, after said bonding, subjecting said wafer for an active layer to a thinning treatment from a rear surface of said wafer for an active layer so as to make a portion in which implanted dopants are diffused in said wafer for an active layer be an SO1 layer.   
     
     
         13 . A method for manufacturing a bonded SOI substrate according to  claim 12 , wherein an oxide film is formed in said wafer for a support substrate before bonding with said wafer for an active layer. 
     
     
         14 . A method for manufacturing a bonded SOI substrate, comprising:
 a step of implanting dopants into a wafer for an active layer which is non-doped or in which dopants are present at low density from a surface of said wafer for an active layer;   a step of, after said ion implantation, bonding said wafer for an active layer and a wafer for a support substrate on the surface of which an oxide film is formed in a state such that an implanted surface be a bonded surface so as to make said oxide film intervening between both wafers be a buried oxide film;   a step of, after said bonding, heat-treating for bonding so as to strengthen bonding between said wafer for an active layer and said wafer for a support substrate, thereby diffusing said implanted dopants thermally; and   a step of, after said bonding, subjecting said wafer for an active layer to a thinning treatment from a rear surface of said wafer for an active layer so as to make a portion in which said implanted dopants are diffused in said wafer for an active layer be an SO1 layer.