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

Abstract

The temperature-dependent characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) and recessed-gate AlGaN/GaN HEMTs combined with oxygen plasma treatment (rec þ oxy HEMTs) are investigated over a range from 25 to 300 C. The peak transconductance and saturation current of both types of devices decrease with the increase of temperature due to the decline of channel electron mobility. It is interesting to find that the threshold voltage (V TH ) exhibits a positive shift in the conventional HEMT, while a negative shift in the rec þ oxy HEMT with temperature increases. The increase in gate leakage current with the temperature is dominated by tunneling mechanism. Furthermore, the annealing process of 300 and 400 C for 2 min in N 2 ambient are utilized in these two kinds of devices for further estimation, respectively. It is found that the channel mobility can be recovered after the 400 C annealing process, but the V TH shows an obvious negative shift in rec þ oxy HEMTs.

The incorporation of AlScN ferroelectric gate dielectric in AlGaN/GaN-HEMT with polarization-modulated threshold voltage

“…This can be explained by the higher activation ratio of bulk and surface impurities at higher temperatures and herein higher current levels. 24) Figure 6(b) summarizes the distribution of V th as a function of temperature. V th shifts positively by 0.5 V after applying a poling voltage of −5V, and the V th varies only within 0.3 V as temperature increases from 25 to 185 °C, which is quite low thanks to the high curie temperature and stable ferroelectric property of AlScN.…”