GaN HEMT DEVICE STRUCTURE AND METHOD OF FABRICATION

摘要

GaN HEMT device structures and methods of fabrication are provided. A dielectric layer forms a p-dopant diffusion barrier, and low temperature selective growth of p-GaN within a gate slot in the dielectric layer reduces deleterious effects of out-diffusion of p-dopant into the 2DEG channel. A structured Al_xGa_1-xN barrier layer includes a first thickness having a first Al %, and a second thickness having a second Al %, greater than the first Al %. At least part of the second thickness of the Al_xGa_1-xN barrier layer in the gate region is removed, before selective growth of p-GaN in the gate region. The first Al % and first thickness are selected to determine the threshold voltage Vth and the second Al % and second thickness are selected to determine the Rdson and dynamic Rdson of the GaN HEMT, so that each may be separately determined to improve device performance, and provide a smaller input FOM (Figure of Merit).