ABSTRACT
Silicon Metal Oxide Semiconductor Field Effect Transistors (MOSFET) dominate modern microelectronics. Gallium Arsenide Metal Semiconductor Field Effect Transistors (GaAs MESFETs) are “runners-up,” and they find many important niche applications in high-speed or high frequency circuits. This chapter discusses the MESFET principles of operation. It reviews the material properties of semiconductors competing for applications in MESFETs and the properties of Schottky barrier contacts followed by a brief review of MESFET fabrication, and MESFET modeling. The chapter considers wide bandgap semiconductor MESFETs, new emerging hetero-dimensional MESFETs, and discusses applications of the MESFET technology. In degenerate semiconductors, especially in semiconductors with a small electron-effective mass, such as GaAs, electrons can tunnel through the barrier near or at the Fermi level, and the tunneling current is dominant. The most popular MESFETs found in applications in both analog microwave circuits and in digital integrated circuits.
