High transconductance AlGaN/GaN heterostructurefield effect transistors on SiC substrates

Heterostructure field effect transistors have been fabricated using AlGaN/GaN heterostructures grown on n-type SiC substrates. These 0.25 µm-gate devices exhibited a high drain current and DC transconductance of 1.71 A/mm and 222 mS/mm, respectively. In sharp contrast to the high current density HFETs fabricated on sapphire substrates was the absence of the negative differential resistance in the drain characteristics. A drain-to-gate breakdown voltage of 39 V was also obtained.