HIGH-FREQUENCY INP/INGAAS DOUBLE-HETEROJUNCTION BIPOLAR-TRANSISTORS ON A SI SUBSTRATE

Self-aligned high-frequency InP/InGaAs double heterojunction bipolar transistors (DHBT's) have been fabricated on a Si substrate for the first time. A current gain of 40 was obtained for a DHBT with an emitter dimension of 1.6 x 19 mum2. The S parameters were measured for various bias points. In the case of I(C) = 15 mA, f(T) was 59 GHz at V(CE) = 1.8 V, and f(max) was 69 GHz at V(CE) = 2.3 V. Due to the InP collector, breakdown voltage was so high that a high V(CE) of 3.8 V was applied for I(C) = 7.5 mA in the S-parameter measurements to give an f(T) of 39 GHz and an f(max) of 52 GHz.