Self-aligned GaAs p-channel enhancement mode MOS heterostructure field-effect transistor

Abstract

Self-aligned GaAs enhancement mode MOS heterostructure field-effect transistors (MOS-HFET) have been successfully fabricated for the first time. The MOS devices employ a Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> gate oxide, an undoped Al/sub 0.75/Ga/sub 0.25/As spacer layer, and undoped In/sub 0.2/Ga/sub 0.8/As as channel layer. The p-channel devices with a gate length of 0.6 μm exhibit a maximum DC transconductance g/sub m/ of 51 mS/mm which is an improvement of more than two orders of magnitude over previously reported results. With the demonstration of a complete process flow and 66% of theoretical performance, GaAs MOS technology has moved into the realm of reality.