Normally-off mesfet device with stacked gate contact

A normally off MESFET device comprising a semiconductor layer (1), a source contact (2), a drain contact (3) and a stacked gate contact (4), wherein the stacked gate contact (4) comprises a bottom metal layer (41), a top metal layer (43) and an insulating layer (42) between the bottom and top metal layers, wherein the source (2), drain (3) and stacked gate contacts (4) are in contact with the semiconductor layer (1), wherein the bottom metal layer (41) and the semiconductor layer (1) form a Schottky contact, creating a depletion region (5) in the semiconductor layer (1) below the bottom metal layer (41), and wherein extension of the depletion region (5) into the semiconductor layer (1) is configured to be modulated by application of a voltage to the top metal layer (43).