AlGaAs / InGaAs P-n-p HBT's have been fabricated using carbon-doped material grown by nonarsine MOVPE. F(max) of 39 GHz and f(t) of 18 GHz were obtained. Operated in common-base mode, a P-n-p HBT achieved 0.5-W output power with 8-dB gain at 10 GHz; saturated output power was 0.69 W. Results are presented for devices with emitter length from 120 to 600 mum.