Failure modes and mechanisms of InP-based and Metamorphic High Electron Mobility Transistors

This paper reviews most recent results concerning reliability of InP-based and metamorphic high electron mobility transistors (HEMTs). Thanks to research work carried out in the last 10 years, a deeper understanding of failure mechanisms of these devices has been achieved, and process and technology solutions have been found for the control of premature breakdown (related to the reduced energy gap of InGaAs) and of parasitic effects, such as ‘‘kink’’ effects, and transconductance frequency dispersion. After a brief description of impact-ionization effects in InGaAs, an analysis of failure modes and mechanisms of InP and metamorphic HEMTs is carried out, including hot-carrier-induced degradation, gate sinking and Schottky/ohmic contact interdiffusion, hydrogen effects, and donor compensation due to fluorine atoms indiffusion. Results show that reliability of these devices is continuously improving, opening the way for applications in microwave and millimeter-wave systems.