Large-diameter SiC wafer and manufacturing method thereof
From the viewpoint of manufacturing an SiC semiconductor device economically, a present Si device manufacturing line is utilized to make it possible to handle a small-diameter SiC wafer. Polycrystal SiC is grown from at least one surface side of a small-diameter a-SiC single crystal wafer so as to be in a size of an outer diameter corresponding to a handling device of an existing semiconductor manufacturing line, and thereafter the polycrystal SiC on the surface of the α-SiC single crystal wafer is ground to manufacture an increased-diameter SiC of a double structure in which the polycrystal SiC is grown around an outer circumference of the small-diameter α-SiC single crystal wafer.
1. A manufacturing method of a large-diameter SiC wafer comprising the steps of:
placing a small diameter α-SiC single crystal wafer on a graphite plate;
forming a film of polycrystal SiC around an outer circumference of said wafer by depositing polycrystal SiC over the graphite plate and over a surface of the α-SiC single crystal wafer;
grinding the polycrystal SiC on the surface of the α-SiC single crystal wafer to manufacture an increased-diameter SiC of a double structure in which the polycrystal SiC plate portion is planarly formed around an outer circumference of the small-diameter a-SiC single crystal wafer; and
wherein a top and bottom surface of the small diameter α-SiC single crystal wafer is free of the polycrystal SiC.
2. The manufacture method according to claim 1 , further comprising:
masking the α-SiC single crystal wafer with a mask;
depositing the polycrystal SiC over the graphite plate on the mask; and
removing the mask in the grinding, thereby forming the large-diameter SiC wafer.