Investigation of channel mobility in AlGaN/GaN high-electron-mobility transistors

We have investigated the channel mobility in the gated region of a set of high-quality AlGaN/GaN high-electron-mobility transistors (HEMTs). The resistances in the contact, access, and gated regions were extracted from straightforward I-D(V-G) measurements on sets of HEMTs with four different gate-to-drain distances. By correcting for the effects of the contact and access resistances, much more accurate effective mobility curves in the gated region, compared to those reported in the past, have been obtained. The maximum effective mobility in that region has been found to be 1100cm(2)V(-1) s(-1) at carrier density n(s) = 7 x 10(12)cm(-2) at room temperature. We have extracted the mobility curves in a wide range of temperatures (80 to 520 K) and carrier concentrations (up to 1.3 x 10(13)cm(-2)). Our systematic measurements have revealed various dominant scattering mechanisms as the temperature and carrier concentration change. (C) 2016 The Japan Society of Applied Physics