Patent ID: 6087241
Filing Date: 2000-07-11
Classification: H01L

Abstract:
A method of forming thermal silicon dioxide side isolation regions in a semiconductor substrate comprising the steps of:providing a semiconductor substrate;forming an oxynitride layer on a surface of said semiconductor substrate;depositing an amorphous polysilicon layer on a surface of said oxynitride layer;depositing a silicon dioxide layer on a surface of said amorphous polysilicon layer;depositing a silicon nitride layer on a surface said silicon dioxide layer;forming a patterned photoresist layer with openings therein on a surface of said silicon nitride layer;removing portions of said silicon nitride layer, said silicon dioxide layer and said amorphous polysilicon layer beneath said openings in said patterned photoresist layer;removing said patterned photoresist layer lying on said silicon nitride layer;removing exposed portions of said oxynitride layer exposed after the step of removing portions of said silicon nitride layer, said silicon dioxide layer and said amorphous polysilicon layer using said silicon nitride layer as a mask;thermally growing narrow silicon dioxide sidewall isolation regions into said semiconductor substrate through openings formed in said oxynitride layer;removing remaining portions of said silicon nitride layer, said silicon dioxide layer, said amorphous polysilicon layer and said oxynitride layer located on said semiconductor substrate to leave said semiconductor substrate with a bare surface having said narrow silicon dioxide sidewall isolation regions located in surface portions of said semiconductor substrate; andsubsequently forming MOS semiconductor devices in said semiconductor substrate between said narrow silicon dioxide sidewall isolation regions formed in said semiconductor substrate.