In this article we show the effect on the dc and rf transport characteristics of dipole doping at the collector heterojunction in an InP/InGaAs double heterojunction bipolar transistor. We show how the switching characteristics of devices with abrupt undoped InGaAs/InP collector heterojunctions can almost be eliminated by using the dipole doping at that interface and how the high-frequency performance is also improved. ©1997 American Institute of Physics.