Patent ID: 6071775
Filing Date: 2000-06-06
Classification: H01L

Abstract:
A method for forming a peripheral circuit, said method comprising the steps of:forming first and second well regions in a semiconductor substrate, wherein said first well region has a first conductivity type and said second well region has a second conductivity type;forming an isolation masking layer on said substrate wherein said isolation masking layer exposes respective isolation regions on said first and second well regions and wherein said isolation masking layer covers respective first and second active regions of said first and second well regions;simultaneously forming first doped isolation regions in said exposed portions of said first well region having said first conductivity type and second well region having said second conductivity type, wherein said first doped isolation regions have said second conductivity type;forming a second masking layer exposing portions of said isolation regions on said first well spaced from said first active region and exposing portions of said isolation regions on said second well adjacent said second active region;simultaneously forming second doped isolation regions in said exposed portions of said isolation regions on said first well having said first conductivity type spaced from said first active region and in said exposed portions of said isolation regions on said second well having said second conductivity type adjacent said second active region, wherein said second doped isolation regions have said first conductivity type;removing said second masking layer;forming an isolation layer on said isolation regions;removing said isolation masking layer thus exposing said active regions of said substrate;forming respective first and second gate insulating layers on said first and second exposed active regions; andforming respective first and second gate electrodes on said first and second gate insulating layers wherein portions of said active regions are exposed on opposite sides of said gate electrodes.