Gate metallization methods for self-aligned sidewall gate gan hemt

Abstract

A method for fabricating a gate structure for a field effect transistor having a buffer layer on a substrate, a channel layer and a barrier layer over the channel layer includes forming a gate including silicon, forming first sidewalls of a first material on either side and adjacent to the gate, selectively etching into the buffer layer to form a mesa for the field effect transistor, depositing a material layer over the mesa, planarizing the material layer over the mesa to form a planarized surface such that a top of the gate, tops of the first sidewalls, and a top of the material layer over the mesa are on the same planarized surface, depositing metal on the planzarized surface, annealing to form the gate into a metal silicided gate, and etching to remove excess non-silicided metal.