Abstract: A method of forming a trench gate field effect transistor includes the following processing steps. Trenches are formed in a semiconductor substrate. The semiconductor substrate is annealed in an ambient including hydrogen gas. A dielectric layer lining at least the sidewalls of the trenches is formed. During the time between annealing and forming the dielectric layer, the semiconductor substrate is maintained in an inert environment to prevent formation of native oxide along sidewalls of the trenches prior to forming the dielectric layer.