Thermal Field Analysis for New AlGaN/GaN HEMT with Partial Etched AlGaN Layer

Abstract

In order to explore the distribution of the device temperature field, this paper takes the new AlGaN/GaN HEMT with partial etched AlGaN layer as the research object. First, the ISE TCAD software is used to simulate the temperature field of AlGaN/GaN HEMT in two dimensions. The simulation results show a decrease of the maximum temperature and average junction temperature in the device channel with shorter thickness of the etched AlGaN layer. As the etching length increases, the hot spot temperature near the gate edge decreases, and the new hot spot position gradually shifts to the drain, which results in a more uniform distribution in the channel. Then, Raman spectroscopy is used to measure the channel junction temperature of AlGaN/GaN HEMTs. The results indicate that when the power dissipation is 0.3W and the etching depth is 5, 10, 15nm, the average channel junction temperature of the new etched AlGaN/GaN HEMT is 9.7%, 17.4% and 30.3% lower than that of the ordinary AlGaN/GaN HEMT, respectively. And the highest temperature of the new AlGaN/GaN HEMT also decreases. We can see that etching the barrier layer of AlGaN/GaN HEMT can not only improve the breakdown voltage, but also effectively reduce the channel junction temperature, and establish the relationship between the high power and thermal stability of the AlGaN/GaN HEMTs.