Extrinsic Base Surface Passivation in Terahertz GaAsSb/InP DHBTs Using InGaAsP Ledge Structures

Type-II GaAsSb/InP double heterojunction bipolar transistors (DHBTs) with a novel InGaAsP ledge structure were studied utilizing a 2-D hydrodynamic physical device model for the first time. The proposed ultrathin InGaAsP ledge design provides a simple and effective approach to suppress the emitter size effect and enables nanoscale GaAsSb/InP DHBTs to further increase the operating frequencies and integration levels for submillimeter-wave applications.