A method of forming a field effect transistor includes the following steps. A trench is formed in a semiconductor region, and a shield dielectric layer lining lower sidewalls and a bottom surface of the trench is formed. A shield electrode is formed in a lower portion of the trench, and a dielectric layer is formed along upper trench sidewalls and over the shield electrode. A gate electrode is formed in the trench over the shield electrode, and an interconnect layer connecting the gate electrode and the shield electrode is formed.