Pnp HBT with 66 GHz f/sub max/

Abstract
The total emitter to collector delay for a Pnp AlGaAs/GaAs HBT has been reduced to 4.8 ps by employing a thin base (325 /spl Aring/) and collector (2300 /spl Aring/). Simultaneously, a low base sheet resistance of 170 ohms/square was achieved with tellurium doping. A higher collector doping than is typically used permitted operation at collector current densities in excess of 5/spl times/10/sup 4/ A/cm/sup 2/. A single emitter (2/spl times/4 /spl mu/m/sup 2/) and a single base contact device topology has an f/sub t/ and f/sub max/ of 33 and 66 GHz, respectively.