| 摘要 |
PROBLEM TO BE SOLVED: To obtain a dielectric isolation wafer which can grow a polysilicon layer without generation of voids on the dielectric isolation oxide film and a method of manufacturing the same wafer. SOLUTION: After a dielectric isolation oxide film 14 is formed with the oxidization heat treatment on the surface of a silicon wafer 10 having the dielectric isolation groove, a seed polysilicon layer 15 is grown on this film 14 by the 130 Pa, low pressure and low temperature CVD method at about 600 deg.C. Next, on the seed polysilicon layer 15, a thick high temperature poly- silicon layer 156 is grown by a high temperature CVD method of about 1250 deg.C. The low pressure and low temperature CVD method assures slower growth rate of polysilicon and higher flatness of the surface. Therefore, when the high temperature polysilicon layer 16 is grown by the high temperature CVD method on the surface of the seed polysilicon layer 15 as the base surface, the polysilicon grows in the uniform thickness from the entire part of such a base surface. As a result, generation of voids between the film 14 and the high temperature layer 16 is suppressed.
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