This paper reports on the structural and electrical properties of AlGaN/GaN heterostructures grown onto 2°-off-axis silicon carbide (4H–SiC) epitaxial layers. The quality of the grown heterostructures was assessed by a combination of different analytical techniques, revealing a density of conductive dislocations in the order of 1 × 109 cm−2. Electrical characterizations of test patterns and transistors provided insights into the transport properties in the two-dimensional electron gas channel, demonstrating a high current density and a field effect mobility (μFE) of about 1800 cm2/Vs. The temperature dependence of μFE allowed us to identify optical phonon scattering as the dominant transport mechanism in the system at high temperature. In addition to demonstrating the suitability of 2°-off-axis 4H–SiC epilayers for the growth of functional AlGaN/GaN high electron mobility transistors, these results provide useful insights for device manufacturers aiming at the monolithic integration of novel GaN devices onto SiC epitaxial layers.
Roccaforte et al. (Fri,) studied this question.