Method for forming a microwave field effect transistor with high operating voltage

Abstract

A microwave field effect transistor () has a high conductivity gate () overlying a double heterojunction structure () that has an undoped channel layer (). The heterojunction structure overlies a substrate (). A recess layer that is a not intentionally doped (NID) layer () overlies the heterojunction structure and is formed with a predetermined thickness that minimizes impact ionization effects at an interface of a drain contact of source/drain ohmic contacts () and permits significantly higher voltage operation than previous step gate transistors. Another recess layer () is used to define a gate dimension. A Schottky gate opening () is formed within a step gate opening () to create a step gate structure. A channel layer () material of InGaAs is used to provide a region of electron confinement with improved transport characteristics that result in higher frequency of operation, higher power density and improved power-added efficiency.