Methods for manufacturing silicon wafer and silicon epitaxial wafer, and silicon epitaxial wafer

Abstract

There is provided a method for manufacturing a silicon wafer or a silicon epitaxial wafer capable of imparting an excellent IG capability thereto in a stable manner by simultaneously realizing higher density of oxide precipitates and larger sizes thereof at a stage prior to a device fabrication process. The present invention is a method for manufacturing a silicon wafer wherein the silicon wafer is subjected to heat treatment to impart a gettering capability thereto comprising at least the following three steps of: a temperature raising step A for generating oxygen precipitation nuclei; a temperature raising step B for growing the oxygen precipitation nuclei; and a constant temperature keeping step C for growing the oxygen precipitation nuclei into oxide precipitates of larger sizes.

1 .- 8 . (canceled)  
   
   
       9 . A method for manufacturing a silicon wafer comprising the steps of: keeping the silicon wafer having grown-in precipitation nuclei generated in a growth step of a silicon single crystal at a temperature T 4 ° C. in the range of from 500° C. to 700° C. for a prescribed time t 1 ; then raising the temperature of the silicon wafer to a temperature T 5 ° C. in the range of from 1000° C. to 1230° C. at a temperature raising rate of 5° C./min or less; and keeping the temperature thereof at the temperature T 5 ° C. for a prescribed time t 2 , thereby the grown-in precipitation nuclei being grown into oxide precipitates each of a size equal to or larger than one having a gettering capability, and oxygen in the vicinity of a surface of the silicon wafer being out-diffused.  
   
   
       10 . The method for manufacturing a silicon wafer according to  claim 9 , wherein the keeping time t 1  at the T 4 ° C. is 15 min or longer.  
   
   
       11 . The method for manufacturing a silicon wafer according to  claim 9 , wherein the keeping time t 2  at the T 5 ° C. is 30 min or longer.  
   
   
       12 . The method for manufacturing a silicon wafer according to  claim 9 , wherein oxygen concentration of the silicon wafer having the grown-in precipitation nuclei is 16 ppma or higher.  
   
   
       13 .- 26 . (canceled)  
   
   
       27 . A method for manufacturing a silicon epitaxial wafer comprising the steps of: keeping a silicon wafer having grown-in precipitation nuclei generated in a growth step of a silicon single crystal at a temperature T 11 ° C. in the range of from 500° C. to 700° C. for a prescribed time t 7 ; then raising the temperature of the silicon wafer to a temperature T 12 ° C. in the range of from 1000° C. to 1100° C. at a temperature raising rate of 5° C./min or less; keeping the temperature thereof at the temperature T 12 ° C. for a prescribed time t 8 , thereby the grown-in precipitation nuclei being grown to sizes each equal to or larger than one not to be annihilated in a subsequent epitaxial growth step; and thereafter performing epitaxial growth on a surface of the silicon wafer.  
   
   
       28 . The method for manufacturing a silicon epitaxial wafer according to  claim 27 , wherein the prescribed time t 7  is 15 min or longer.  
   
   
       29 . The method for manufacturing a silicon epitaxial wafer according to  claim 27 , wherein the prescribed time t 8  is 30 min or longer.  
   
   
       30 . The method for manufacturing a silicon epitaxial wafer according to  claim 27 , wherein oxygen concentration of the silicon wafer is 16 ppma or higher.  
   
   
       31 . The method for manufacturing a silicon epitaxial wafer according to  claim 27 , wherein a size of the oxide precipitate is 40 nm or larger in diameter.  
   
   
       32 .- 35 . (canceled)  
   
   
       36 . The method for manufacturing a silicon wafer according to  claim 9 , wherein a size of the oxide precipitate is 40 nm or larger in diameter.  
   
   
       37 . The method for manufacturing a silicon wafer according to  claim 9 , wherein a diameter of the silicon wafer is 300 mm or larger.  
   
   
       38 . The method for manufacturing a silicon epitaxial wafer according to  claim 27 , wherein a diameter of the silicon wafer is 300 mm or larger.