GaInP/GaAs HBT's for high-speed integrated circuit applications

GaInP/GaAs HBTs (heterojunction bipolar transistors) have been fabricated to investigate their noise behavior and high-speed circuit performance. The HBT epitaxial structure was grown by MOCVD (metal-organic chemical vapor deposition) with carbon p-type dopant and silicon n-type dopant. The measured 1/f noise is significantly lower than that of the AlGaAs/GaAs HBTs and comparable with that of silicon bipolar transistors. More significantly the noise 'bump' (Lorentzian components) in the intermediate frequency range (10-100 kHz) was not observed. The RF performance of gain blocks and frequency dividers (divide by 4) were measured and found to be comparable with that of the baseline AlGaAs/GaAs HBTs. The V/sub cc/ offset voltage was measured to be less than 140 mV for small size HBTs and 70 mV for large transistors with emitter dimensions of 70 mu m*70 mu m.