FABRICATION METHOD FOR GAN SEMICONDUCTOR POWER TRANSISTOR WITH SLANTED GATE FIELD PLATE

A GaN semiconductor power transistor structure with a slanted gate field plate, and a method of fabrication are disclosed. The gate field plate comprises a gate metal field plate and slanted gate field plate structure formed using contact metal and/or interconnect metal. The slanted structure of the gate field plate is defined by etching of a dielectric layer having a graded composition, to form a slanted opening that is filled with conductive metal. The dielectric thickness under the gate field plate and the slant angle are configured to shape appropriately the electric field in the region between the gate and drain.