Collector-controlled states in charge injection transistors (Invited Paper)

We review recent theoretical studies of the symmetry properties of charge injection transistors. These studies, based on continuation modeling and transient device simulation, incorporate self-consistently the electron energy and real-space transfer currents over heterojunction interfaces. Inspection of the full device phase—space reveals a variety of instabilities and a striking novelty of multiply-connected current-voltage characteristics. We have found anomalous steady states in which hot-electron injection occurs in the absence of any voltage between the emitter electrodes. In these states, some of which are not only stationary but also stable with respect to small perturbations, the electron heating is due to the fringing field from the collector electrode. Some of the anomalous states break the reflection symmetry in the plane normal to the channel at midpoint. The study elucidates the formation of hot-electron domains in real-space transfer.