Performance of AlGaAs/GaAs heterostructure bipolar transistors grown by MOVPE

A self-aligned fabrication process for AlGaAs/GaAs heterostructure bipolar transistors grown by metal-organic vapor phase epitaxy has been developed. A DC-amplification of 500 has been achieved on large area devices and a maximum frequency of oscillation, fmax, of more than 30 GHz has been obtained for devices with two stripes of 2.5×10 ¿m emitter area. We have also characterized the intrinsic and extinsic time constants and outlined future device optimization expected to improve the performance into the 60 GHz range.