THz Indium Phosphide Bipolar Transistor Technology

Scaling laws and limits of THz indium Phosphide heterojunction bipolar transistors (HBTs) are presented. The primary limits to scaling through the 32 nm / 3 THz node are the resistivity, penetration depth, and current-carrying capability of the emitter and base contacts. A processes flow with refractory dry-etch emitter and base contacts is presented. Beyond the 32 nm node, degenerate injection in the emitter-base junction limits transconductance and impedes scaling. At the 32 nm node, bandwidths will be sufficient for 1.4 THz transmitters and receivers.