False surface-trap signatures induced by buffer traps in AlGaN-GaN HEMTs

Buffer traps can induce ldquofalserdquo surface-trap signatures in AlGaN-GaN HEMTs, namely the same type of current-mode DLTS peaks and pulse responses that are generally attributed to surface traps. Device simulations are adopted to clarify the underlying physics. Being aware of the above phenomenon is important for both reliability testing and device optimization, as it can lead to erroneous identification of the degradation mechanism, thus resulting in inappropriate correction actions on the technological process.