Effect of Temperature and Al Concentration on the Electrical Performance of GaN and Al0.2Ga0.8N Accumulation-Mode FET Devices
Field-effect transistors were fabricated on GaN and Al0.2Ga0.8N epitaxial layers grown by metal organic chemical vapor deposition (MOCVD) on sapphire substrates. The threshold voltage VTH was higher when AlGaN was used as an active layer. VTH also increased with temperature due to the increased positive polarization charge at the GaN/AlN buffer/sapphire interfaces. Drain current increased at high temperatures even with more positive threshold voltage, which makes GaN-based FET devices attractive for high temperature operation.
Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller
M. J. Tadjer et al., "Effect of Temperature and Al Concentration on the Electrical Performance of GaN and Al0.2Ga0.8N Accumulation-Mode FET Devices", Materials Science Forum, Vols. 645-648, pp. 1215-1218, 2010