InP and GaN high electron mobility transistors for millimeter-wave applications

This paper reviews two important candidates of millimeter- and sub-millimeter-wave applications, InP- and GaN-based high electron mobility transistors (HEMTs). For both devices, the gate length scaling has already well developed to the dimension of 15-30 nm. For further improvement in the cutoff frequency, an importance of the careful managements of parasitic components in the devices is discussed. Successful reduction of the parasitic gate delay time will enable us to achieve a cutoff frequency of over 1 THz in InP-based HEMTs and that of over 500 GHz in GaN-based HEMTs.