Submicron transferred-substrate heterojunction bipolar transistors with greater than 8000 GHz f/sub max/

We report submicron transferred-substrate AlInAs/GaInAs heterojunction bipolar transistors. Devices with 0.4 /spl mu/m emitter and 0.9 /spl mu/m collector widths have 17.5 dB unilateral gain at 110 GHz. Extrapolating at -20 dB/decade, the power gain cut-off frequency f/sub max/ is 820 GHz.