HIGH-TEMPERATURE PERFORMANCE OF ALGAN GAN HFETS ON SIC SUBSTRATES/

The results on performance of AlGaN-GaN Heterostructure Field Effect T ransistors (HFET's) grown on SiC substrates are reported. The maximum transconductance of these devices was 142 mS/mm and the source-drain c urrent was as high as 0.95 A/mm. The maximum dissipated DC power at ro om temperature was 0.6 MW/cm(2), which is more than three times higher than in similar devices grown on sapphire. This high thermal breakdow n threshold was achieved primarily due to the effective heat sink due through a SiC substrate. These devices demonstrated stable performance at elevated temperatures up to 250 degrees C. The source-drain curren t saturation was observed up to 300 degrees C. The leakage current in the below threshold regime was temperature-activated with the activati on energy of 0.38 eV.