Comparison of AlGaN/GaN high electron mobility transistors grown on AlN/SiC templates of sapphire

摘要

The temperature and gate length effects on dc performance of AlGaN/GaN high-electron mobility transistors (HEMTs) grown on AlN/SiC templates or sapphire substrates are reported. The defect density in the structures grown on the AlN/SiC template is significantly lower than those grown on sapphire, as measured by transmission electron microscopy. Reverse breakdown voltages above 40 V were obtained for 0.25 μm gate length devices on both types of substrate. Extrinsic transconductances of ～200 mS/mm for HEMTs on sapphire and ～125 mS/mm for devices on AlN/ SiC were achieved, with the latter devices showing significantly lower self-heating effects.