A method of forming a metal oxide semiconductor field effect transistor with improved gate-induced drain leakage performance, the method including providing a semiconductor substrate having a gate trench formed therein, performing an ion implantation process on upper portions of sidewalls of the gate trench to make the upper portions more susceptible to oxidation relative to non-implanted lower portions of the sidewalls, and performing an oxidation process on surfaces of the substrate, wherein the implanted upper portions of the sidewalls develop a thicker layer of oxidation relative to the non-implanted lower portions of the sidewalls.