Study of the Temperature Dependence of AlGaN/GaN HEMTs with Oxygen Plasma Treatment

摘要

The temperature-dependent characteristics of AlGaN/GaN high electronrnmobility transistors (HEMTs) and recessed-gate AlGaN/GaN HEMTs combinedrnwith oxygen plasma treatment (rec+oxy HEMTs) are investigated overrna range from 25 to 300 ℃. The peak transconductance and saturation currentrnof both types of devices decrease with the increase of temperature due to therndecline of channel electron mobility. It is interesting to find that the thresholdrnvoltage (VTH) exhibits a positive shift in the conventional HEMT, while arnnegative shift in the rec+oxy HEMT with temperature increases. Thernincrease in gate leakage current with the temperature is dominated byrntunneling mechanism. Furthermore, the annealing process of 300 and 400 ℃rnfor 2 min in N2 ambient are utilized in these two kinds of devices for furtherrnestimation, respectively. It is found that the channel mobility can bernrecovered after the 400℃ annealing process, but the VTH shows an obviousrnnegative shift in recþoxy HEMTs.