Sic epitaxial wafer and method for producing same, and device for producing sic epitaxial wafer

Abstract

A SiC epitaxial wafer manufacturing method of the present invention includes: manufacturing a SiC epitaxial wafer including a SiC epitaxial layer on a surface of a SiC single crystal wafer while supplying a raw material gas into a chamber using a SIC epitaxial wafer manufacturing apparatus; and manufacturing a subsequent SiC epitaxial wafer after measuring a surface density of triangular defects originating from a material piece of an internal member of the chamber on the SiC epitaxial layer of the previously manufactured SiC epitaxial wafer.

1 . A SiC epitaxial wafer comprising:
 a SiC epitaxial layer formed on a SiC single crystal substrate with an off-angle, wherein   a surface density of triangular defects, which is present in the SiC epitaxial layer and has a material piece of an internal member of a chamber as a starting point, is 0.5 pieces/cm 2  or less.   
     
     
         2 . The SiC epitaxial wafer according to  claim 1 , wherein the material piece, which becomes the starting point, is formed of carbon or silicon carbide. 
     
     
         3 . A SiC epitaxial wafer manufacturing method comprising:
 manufacturing a SiC epitaxial wafer including a SiC epitaxial layer on a surface of a SiC single crystal wafer while supplying a raw material gas into a chamber using a SiC epitaxial wafer manufacturing apparatus; and   manufacturing a subsequent SiC epitaxial wafer after measuring a surface density of triangular defects having a material piece of an internal member of the chamber as a starting point on the SiC epitaxial layer of the previously manufactured SiC epitaxial wafer, wherein   the SiC epitaxial wafer manufacturing apparatus includes a susceptor that includes a wafer placement unit on which the wafer is placed, a top plate that is disposed to face an upper surface of the susceptor so that a reaction space is formed between the susceptor and the top plate, and a shielding plate that is disposed to be close to a lower surface of the top plate to such an extent that a deposit is prevented from being attached to the lower surface of the top plate, and   the shielding plate is formed of silicon carbide or a surface of the shielding plate facing the susceptor is covered with a silicon carbide film or a pyrolytic carbon film.   
     
     
         4 . The SiC epitaxial wafer manufacturing method according to  claim 3 , wherein the shielding plate is replaced and the subsequent SiC epitaxial wafer is manufactured when the surface density of the triangular defects having the material piece of the internal member of the chamber as the starting point is greater than a predetermined density as a result of the measurement. 
     
     
         5 . A SiC epitaxial wafer manufacturing method comprising:
 manufacturing a SiC epitaxial wafer including a SiC epitaxial layer on a surface of a SiC single crystal wafer while supplying a raw material gas into a chamber using a SiC epitaxial wafer manufacturing apparatus; and   manufacturing a subsequent SiC epitaxial wafer after measuring a surface density of triangular defects having a material piece of an internal member of the chamber as a starting point on the SiC epitaxial layer of the previously manufactured SiC epitaxial wafer, wherein   the SiC epitaxial wafer manufacturing apparatus includes a susceptor that includes a wafer placement unit on which the wafer is placed and a top plate that is disposed to face an upper surface of the susceptor so that a reaction space is formed between the susceptor and the top plate, and   the top plate is formed of silicon carbide or a surface of the top plate facing the susceptor is covered with a silicon carbide film or a pyrolytic carbon film.   
     
     
         6 . The SiC epitaxial wafer manufacturing method according to  claim 5 , wherein the top plate is replaced and the subsequent SiC epitaxial wafer is manufactured when the surface density of the triangular defects having the material piece of the internal member of the chamber as the starting point is greater than a predetermined density as a result of the measurement. 
     
     
         7 . A SiC epitaxial wafer manufactured using the SiC epitaxial wafer manufacturing method according to  claim 3 . 
     
     
         8 . A SiC epitaxial wafer manufacturing apparatus comprising:
 a susceptor that includes a wafer placement unit on which a wafer is placed;   a top plate that is disposed to face an upper surface of the susceptor so that a reaction space is formed between the susceptor and the top plate; and   a shielding plate that is disposed to be close to a lower surface of the top plate to such an extent that a deposit is prevented from being attached to the lower surface of the top plate, wherein   the shielding plate is formed of silicon carbide or a surface of the shielding plate facing the susceptor is covered with a silicon carbide film or a pyrolytic carbon film, and   an epitaxial layer is formed on a surface of the wafer while a raw material gas is supplied into a chamber.   
     
     
         9 . A SiC epitaxial wafer manufacturing apparatus comprising:
 a susceptor that includes a wafer placement unit on which a wafer is placed; and   a top plate that is disposed to face an upper surface of the susceptor so that a reaction space is formed between the susceptor and the top plate, wherein   the top plate is formed of silicon carbide or a surface of the top plate facing the susceptor is covered with a silicon carbide film or a pyrolytic carbon film, and   an epitaxial layer is formed on a surface of the wafer while a raw material gas is supplied into a chamber.   
     
     
         10 . The epitaxial wafer manufacturing apparatus according to  claim 8 , wherein a film thickness of the silicon carbide film or the pyrolytic carbon film is within the range of 20 μm to 100 μm. 
     
     
         11 . The epitaxial wafer manufacturing apparatus according to  claim 8 , further comprising: a heating device that is disposed on a lower surface side of the susceptor and/or an upper surface side of the top plate.