Patent ID: 6096663
Filing Date: 2000-08-01
Classification: C04B,H01L

Abstract:
A method of forming a laterally-varying charge profile in a silicon carbide (SiC) substrate, which comprises:forming a polysilicon layer on said SiC layer substrate;forming a silicon nitride (Si.sub.3 N.sub.4) layer on said polysilicon layer;patterning said Si.sub.3 N.sub.4 layer to provide a plurality of Si.sub.3 N.sub.4 layer segments which are spaced apart in the lateral direction and providing said Si.sub.3 N.sub.4 layer segments with openings therebetween which are of varying widths;oxidizing said polysilicon layer using said layer segments as an oxidation mask to form a silicon dioxide (SiO.sub.2) layer of varying thickness from said polysilicon layer and to form a polysilicon layer portion therebeneath of varying thickness;removing said Si.sub.3 N.sub.4 layer segments and at least partially removing said SiO.sub.2 layer; andion implanting a dopant into said SiC substrate using said polysilicon layer portion of varying thickness as an implantation mask to form said laterally-varying charge profile in the SiC substrate.