Role of Transport During Transient Phenomena in AlGaN/GaN Heterostructure FETs

Transient phenomena in AlGaN/GaN heterostructure field-effect transistors are attributed to trapping and detrapping of electrons from deep localized states, and the measured activation energies are conventionally associated with the electron capture and emission processes. This standard interpretation ignores, however, transport between the two-dimensional electron gas and the trap. Using gated van der Pauw structures, we demonstrate that the transient behavior is determined by transport (at least for the trapping process). The measured activation energy is, therefore, a characteristic of the transport process rather than the emission-capture processes.