Self-Aligned InP/InGaAs Single Heterojunction Bipolar Transistor with Novel Micro-airbridge Structure and Quasi-coplanar Contacts

摘要

The fabrication and performance of a self-aligned InP/InGaAs single heterojunction bipolar transistor (SHBT)with a novel micro-airbridge structure and co-planar-contacts are described. The reported structure is based on anisotropy wet, etching of InP and selective wet, etching between InP and InGaAs. The device with a 1.5 × 5 μm2emitter demonstrates a current gain of 30 at collector current Ic = 10 mA and extrapolates the current-gain cutoff frequency Ft of 53 GHz and the maximum oscillation frequency Fmax of 72 GHz. Compared with the one using the conventional structure, the maximum oscillation frequency of the device with micro-airbridge is dramatically improved from 45 GHz to 72 GHz. This result reveals that the extrinsic capacitance of small size SHBT can be greatly reduced.