The fabrication process of AlGaAs/GaAs HBTs with low base resistance and low collector capacitance for 10 Gb/s IC chip sets

A fabrication technology for AlGaAs/GaAs HBTs (heterojunction bipolar transistors) with low base resistance and low collector capacitance is developed. Self-aligned AlGaAs/GaAs HBTs show a high cutoff frequency of 45 GHz and maximum oscillation frequency of 70 GHz at collector current of 3.5 mA, and were successfully applied to IC chip sets for 10 Gb/s optical transmission. Among the fabricated 10 Gb/s IC chip sets, an AGC amplifier with 20 dB gain and 13.7 GHz bandwidth and a decision circuit with 66 mVp-p of ambiguity at 10 Gb/s are obtained, which are fully applicable to 10 Gb/s systems.<
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