ABSTRACT
This chapter outlines the motivation for researchers, device engineers and circuit designers to go for High Electron Mobility Transistors. It has been more than 25 years since the high electron mobility transistor (HEMT) was first proposed in 1979. The key concept of the HEMT is the field-effect modulation of the high-mobility two-dimensional electron gas (2DEG) at the heterostructure consisting of one of the selectively doped semiconductor pairs, such as n-AlGaAs/GaAs and n-InAlAs/InGaAs. In 1985, for the first time, HEMTs were used commercially as a cryogenic low noise amplifier, for a radio telescope to detect microwave signals from a dark nebula, leading to the discovery of a new interstellar molecule. Mass production of HEMTs for the first consumer application was started around 1986, when low-noise HEMT amplifiers were exclusively used in broadcasting satellite receivers, providing the technology a foundation for further development in microwave and millimeter-wave applications such as cell-phone handsets and automotive radars. The evolution of HEMT has been presented in this paper. A detailed overview of the different current and futuristic field effect transistor technologies including BJTs, MESFETS, MOSFETs, DG-MOSFETs, SB-MOSFETs, Tunnel FETs, FinFETs and Junctionless Transistors, Quantum Well MOSFETs, silicon nanowire FETs, carbon nanotube FETs and spintronics based transistors. HEMTs have been discussed in detail, along with their applications in advanced MMIC and TMIC technologies, sub-millimeter wave applications, terahertz applications, 4G/5G communications, enhancements in data capacity for advanced wireless communications, medical, space and defense/military applications.
