Physics and technological advantages underlying some doping induced design criteria of InP/In0.53Ga0.47As HBTs have been discussed. Attention has been paid to parameters such as doping in the base region, base resistance versus doping dependent base region grading, the emitter-base junction design, and the recombination at the external base region. The dependence of built-in electric field in the base region on the nature of doping has been elucidated. (C) 2002 Elsevier Science Ltd. All rights reserved.