Method of fabricating semiconductor device with dual gate structure

Abstract

A method for fabricating a semiconductor device with a dual gate structure is provided. The method includes: forming a gate oxide layer over a substrate; forming a gate conductive layer over the gate oxide layer; forming an amorphous carbon layer over the gate conductive layer; forming a photosensitive pattern over the amorphous carbon layer; etching the amorphous carbon layer using the photosensitive pattern as an etch mask to form a patterned amorphous carbon layer; performing an ion implantation process using the patterned amorphous carbon layer as an ion implantation barrier to implant an impurity onto the gate conductive layer; removing the patterned amorphous carbon layer; and patterning the gate conductive layer to form a gate structure.