In_xGa_1-xAs_YP_1-Y quaternary etch stop for improved chemical resistivity of gallium arsenide field effect transistors

摘要

A process for fabricating a semiconductor device. The process including (a) growing a channel layer on a buffer layer, (b) growing a barrier layer on the channel layer, (c) epitaxially growing a quaternary etch-stop layer on the barrier layer, (d) growing a first contact layer on the quaternary etch-stop layer, (e) growing a second contact layer on the first contact layer, (f) etching portions of the second contact layer to reveal a first recess surface, and (g) etching portions of the first contact layer to reveal a second recess surface. The second contact layer may be a highly doped contact layer. The second recess surface generally forms a gate region. The first and the second contact layers have a first etch rate and the quaternary etch-stop layer has a second etch rate in a chosen first etch chemistry.