InAlN-barrier HFETs with GaN and InGaN channels

Advantages and drawbacks of InN‐containing GaN‐based heterostructure field‐effect transistors (HFETs) are reviewed. The main attention is paid to fundamental processes and experimental observations associated with hot‐electron transport in two‐dimensional electron gas (2DEG) channels subjected to high electric fields. Complementary information is obtained from fluctuations. When interface roughness and alloy scattering are minimized, an important transport limitation originates from additional scattering of hot electrons by non‐equilibrium longitudinal optical (LO) phonons (hot phonons) governed by the hot‐phonon temperature and the hot‐phonon decay into acoustic phonons. The ultrafast decay is observed for high supplied power where the hot‐phonon lifetime of ∼60 fs is found. The optimal 2DEG density for the fastest decay of hot phonons is estimated and associated with LO‐phonon–plasmon resonance. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)