Current collapse and reliability of III-N heterostructure field effect transistors

Measurements of GaN HFET lifetime as a function of temperature show that different degradation mechanisms are involved at low temperatures (close to room temperature) and high temperatures (above 150 degrees C). The degradation at low temperatures is linked to the trap generation and can be explained using the current collapse model. At higher temperatures, other degradation mechanisms become important or even dominant. The current collapse related degradation can be diminished by using improved device design, which will greatly increase the overall lifetime (up to a long lifetimes obtained by extrapolating high temperature data to room temperature). (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.