Advanced IC fabrication technology using reliable, small-size, and high-speed AlGaAs/GaAs HBTs

Reliable, small-size, and high-speed AlGaAs/GaAs HBTs (heterojunction bipolar transistors) have been developed using a carbon-doped thin base layer and O/sup +/-implant E/B (emitter/base) junction isolation. This isolation reduces the recombination current at the implanted edge, resulting in improved current gain. The use of carbon dopant for the base layer improves device reliability. A thin (0.04 mu m) base reduces base transit time, making it possible to achieve a high cutoff frequency of 103 GHz. A one-by-eight static frequency divider and a one-by-four/one-by-five two-modulus prescaler fabricated to investigate circuit performance successfully operated over 10 GHz. The 1- mu m*2.4- mu m emitters used in the divider are the smallest HBT applied to ICs ever reported. This result indicates that the proposed technology is promising for the development of reliable and high-speed HBT ICs.<>