Effect of epitaxial layer crystal quality on DC and RP characteristics of AlGaN/GaN short-gate HEMTs

摘要

The DC and RF performances of short-gate AlGaN/GaN high-electron transistors (HEMT) on SiC and sapphire substrates have been investigated. There were differences in surface morphology, electron mobility, and contact resistance between SiC and sapphier wafers. The contact resistance limited and dispersed measured transconductance (g_m). The intrinsic gm after subtraction of the source resistance contribution and gate-length dependences of cut-off frequency were the same. These results indicates that the effective electron velocity is the same for both samples.