Method of forming an isolation region

摘要

A method of forming an isolation region in a semiconductor device, comprises: forming a multilayer comprising a first oxide layer (3) formed on a region of semiconductor substrate (1), a polysilicon layer (5) above the first oxide layer and a nitride layer above the polysilicon layer; removing material except at least the polysilicon layer from a predetermined portion of the multilayer to leave active regions separated by at least one isolation region; forming a channel stopper (11) at the isolation region by ion-implantation of a conductive impurity into the substrate; removing the nitride layer and forming an isolation layer (15) from the polysilicon layer; forming a spacer (17) at a sidewall of the isolation layer depositing a further oxide layer on the entire surface of the region and etching back said oxide layer; forming a gate oxide layer (19) on the exposed substrate; and forming a diffusion region (23) below the gate oxide layer.