Scaling of InP/GaAsSb DHBTs: A Simultaneous fT/fMAX = 463/829 GHz in a 10 μm Long Emitter

The scaling behavior of Type-II InP/GaAsSb double heterojunction bipolar transistors (DHBTs) is studied and a 10 μm long emitter with cutoff frequencies of $f_{\text{T}}/f_{\text{MAX}}=463/829$ GHz and is demonstrated. Such a high $f_{\text{MAX}}$ was made possible by aggressive lateral scaling of the base-collector (BC) mesa which helps to reduce the extrinsic BC capacitance. The limitations in furthering the lateral scaling for these devices are examined. The present transistors show the highest $f_{\text{MAX}}$ for a $10 \mu\text{m}$ long emitter for any HBT, indicating the excellent scaling properties of Type-II DHBTs.