Abstract
InP/InGaAs PNP heterojunction bipolar transistor (HBT) layers have been grown by metalorganic chemical vapor deposition (MOCVD) and devices have been fabricated using a self-aligned processing technology. A zinc-doped InP layer has been employed as the wide-bandgap emitter layer for the PNP HBT. The base layer used a 500 Å thick n-type InGaAs layer doped at 5 × 10 18 cm -3 . Successful high frequency operation of these devices has been demonstrated. A single-emitter 1 × 20 μm 2 MOCVD-grown PNP InP/InGaAs HBT achieved current gain cutoff frequency (f T ) of more than 11 GHz at a current density (J C ) of 8.25 × 10 4 A/cm 2 .