Bias-Increased Trap Emission Underlying the On-Resistance Degradation of AlGaN/GaN Technology

An experimental and numerical study of the on-resistance degradation in AlGaN/GaN-based technology is presented. Back-bias measurements on transmission-line-method (TLM) structures were performed to investigate the mechanism underlying the current degradation. The observed TLM current collapse exhibits Arrhenius behavior, which is associated with traps in the buffer layers. Interestingly, the decay time of the collapse shows a decreasing trend with increasing applied bias, which is here investigated and newly interpreted as a signature of Poole–Frenkel bias-enhanced trap emission. An effective model is discussed and implemented in TCAD simulations to support the experimental findings. In addition to providing justification for the temperature and applied-voltage dependence of the observed degradation trends, the proposed mechanism can also explain the spread in the activation energies measured for acceptor traps in the buffer layers, as reported in the literature for AlGaN/GaN technologies.