MOMBE-grown carbon-doped base self-aligned AlGaAs/GaAs heterojunction bipolar transistors for microwave applications

Abstract

The authors report the first demonstration of completely MOMBE (metal-organic molecular beam epitaxy) grown carbon-doped base self-aligned AlGaAs/GaAs HBTs (heterojunction bipolar transistors) operating at microwave frequencies. Excellent DC and RF characteristics have been achieved. For a 1400-AA-thick base doped at a level of 1*10/sup 19/ cm/sup -3/, cutoff frequency f/sub T/ of 45 GHz and f/sub max/ of 90 GHz were measured from common emitter HBTs. Common base HBTs with total emitter area of 360 mu m/sup 2/ delivered 560 mW output power with 43% of power-added efficiency and 8.9 dB gain at 10 GHz. A high-power MMIC (monolithic microwave integrated circuit) amplifier operating in 8-11 GHz bandwidth has achieved 2 W output power. The device modeling based on measured S-parameters indicates that the performance can be further improved with optimal layer structure and doping profiles.<>