Reverse current thermal activation of AlGaN/GaN HEMTs on Si(1 1 1)

The objective of this paper is to analyze the impact of the high temperature on the on-state and the reverse leakage currents (gate, drain and bulk) of AlGaN/GaN HEMTs grown on Si(1 1 1) in the temperature range of 25–310 °C. After intensive testing, it has been observed that the (drain and gate–to-source) leakage currents exhibit a weak increase with the temperature up to 150 °C. The leakage through the silicon substrate has a primordial role, as the drain reverse leakage appears to be due to electron injection from the Si substrate/AlN/GaN buffer layers into the GaN buffer. At higher temperatures, the activation energy (Ea), extracted from Arrhenius plots, is much higher being Ea = 0.20 eV and Ea = 0.40 eV for drain and gate leakage currents, respectively. We suggest that this relevant thermal activation is related to temperature-dependent thermionic currents over different barriers.

Figure optionsDownload as PowerPoint slide