High current (100mA) InP/InGaAs/InP DHBTs with 330 GHz fmax

We report high fmax and high current InP/InGaAs/InP DHBT in transferred-substrate technology. The common base device with equivalent emitter size of 128 um exhibits fmax of 330 GHz at the current of 100 mA. The common emitter device with emitter area of 64 um shows fmax of 371 GHz when biased at 57 mA. The breakdown voltage of these DHBTs is up to 7 volts at low current density. All the devices are realized in multi-finger structure that was deliberately designed to improve the thermal stability at high power operation and to reduce the parasitics. To our knowledge, this is the highest fmax for a DHBT biased at such high current.