Heterostructure field effect transistors.

The heterostructure field effect transistor (HFET) has made a dramatic impression on ultra-high speed electronics since the pioneering work in the early 1980's. The development of the HFET is reviewed in this paper which will be a chapter in the book "Gallium Arsenide Technology." The structure and properties of the n+GaAs/GaAs are described, followed by a review of process technologies and a survey of novel HFET structures, including those in materials systems other than AlGaAs/GaAs. Finally, the application of HFETs to integrated circuits is discussed.