Patent ID: 6046095
Filing Date: 2000-04-04
Classification: H01L,Y10S

Abstract:
A fabrication process for a semiconductor device utilizing a semiconductor substrate with polysilicon layers, comprising:a first step of effecting heat treatment for said semiconductor substrate including:a base body;N layers (N is an integer greater than or equal to two) of polysilicon layers formed on the back side of said base body, containing boron, a boron concentration C.sub.B(n) in (n)th (n=1, 2, . . . N-1) polysilicon layer from the base body side being lower than a boron concentration C.sub.B(n+1) of (n+1)th polysilicon layer from the base body side; andsilicon oxide layers formed between respective of N layers of polysilicon layers, for capturing contaminating impurity within said polysilicon layers; anda second step of removing a polysilicon layer located at the most back side of said semiconductor substrate.