
A high electron mobility transistor (HEMT) includes a diffusion barrier (22) to prevent gate metal (20) diffusion into the substrate (12) during fabrication and a sacrificial platinum alloy layer (30) forms the Schottky barrier. A method of forming a HEMT includes forming a diffusion barrier of titanium nitride on a platinum layer and applying sufficient heat to cause the platinum layer to alloy with the gallium arsenide layer forming a platinum gallium and platinum arsenide alloy layer and Scho...










