Hot phonons in GaN channels for HEMTs

Abstract Accumulation of non‐equilibrium longitudinal optical (LO) phonons (termed hot phonons) is considered as a possible cause for limitation of hot‐electron drift velocity at high electric fields in a GaN biased channel with a two‐dimensional electron gas (2DEG). Equivalent hot‐phonon temperature and hot‐phonon lifetime are estimated from experimental results on hot‐electron noise at a microwave frequency. Dependence of the hot‐phonon parameters on electron density and channel composition is investigated, and frequency performance of high‐electron‐mobility transistors (HEMTs) is discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)