A multifunctional HBT technology

A self-aligned AlGaAs/GaAs HBT technology has been developed for the fabrication of both high-performance microwave circuits and high-performance digital circuits. The technology provides transistors with high f/sub max/ (up to 218 GHz), high f/sub t/ (up to 98 GHz), and high efficiency (power added efficiency higher than 67.8% at 10 GHz) microwave amplification to at least 20 GHz. A MMIC amplifier has demonstrated 7-dB gain between 14 and 24 GHz. Excellent performance of high-speed digital circuits, such as ring oscillators, frequency dividers, MUXs, DEMUXs, and phase detectors has also been achieved on the same wafer. A multifunction chip covering the entire microwave band is feasible. The technology requirements and self-aligned AlGaAs/GaAs HBT process for multifunction chip application are described. The performances of HBTs, MMIC, and high-speed digital circuits fabricated on the same wafer are reported.<>