Physical Insights Into the Lattice Temperature Dependent Evolution of Hot Electron Distribution in GaN HEMTs on C-Doped GaN-on-Si

In this work, with the help of detailed experimentation and well-calibrated computations, we probe into the physical mechanism governing temperature dependence of the hot electron distribution in AlGaN/GaN HEMTs. Experimentations in semi-ON state, including electroluminescence (EL) microscopy and spectroscopy analysis, revealed the emergence of a hot electron hotspot at the drain edge (DE) of the HEMT as device temperature was increased. Drain bias and vertical leakage dependence of the process are examined experimentally to determine factors affecting it. Well-calibrated computations revealed a unique surface and buffer trap charging-discharging phenomenon led electric field and electron density modulation to be responsible for the observed phenomenon. A physical mechanism based on the experimental and computational observations is also proposed and subsequently validated using dedicated experiments.