Molecular beam epitaxial AlGaN/GaN high electron mobility transistors leakage thermal activation on silicon and sapphire

GaN-based power switches are expected to play a key role in uncooled electronics at elevated temperatures. In this paper we explore the thermal activation mechanisms taking place in analogous AlGaN/GaN high electron mobility transistors grown on silicon and sapphire. The on-resistance (α = 1.4/1.8 [Si/sapphire]) and saturation current (α = −1.5/−1.8) temperature coefficients, the thermal activation energies (Ea = 0.02–0.30/0.30 eV), the drain current on/off ratio (α = −1.5–9.1/−9.4), or the thermal impedances (Rth = 76.9/125.8 K/W) were determined and comparatively analyzed by means of physical-based models which include polar-optical phonon scattering, Poole-Frenkel trap assisted and Schottky emission, and the channel self-heating.