METHOD OF FORMING GATE INSULATION FILM OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method of forming the gate insulation film of a semiconductor device is provided which is adapted to improve the reliability of the gate insulation film in forming a dual gate. CONSTITUTION: A method of forming the gate insulation film of a semiconductor device comprises steps of: forming an insulation film(22) on a semiconductor substrate(21); forming a nitride layer(22a) by injecting nitrogen ions into the top surface of the insulation film(22); defining the insulation film(22) into a first region and a second region using a photomask; removing the nitride layer(22a) in the second region and then continuously removing the insulation film(22) up to a prescribed depth thereof; removing the photomask; removing the nitride layer(22a) in the first region and at the same time removing the second insulation film(22b) to expose the substrate corresponding to the second region; forming a gate insulation film(22d), having the first thickness in the first region by an oxidation process; and forming a gate insulation film(22e), having the second thickness less than that of the first thickness.