GaAsSb-Based DHBTs With a Reduced Base Access Distance and $f_{\mathrm {T}}/f_{\mathrm {MAX}}=$ 503/780 GHz

Abstract

We report InP/GaAsSb/InP double heterojunction bipolar transistors (DHBTs) with simultaneous current and power gain cutoff frequencies of f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</sub> = 503/780 GHz. Devices with a 0.2 × 4.4 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> emitter area feature a peak DC current gain β = 17 and a common-emitter breakdown voltage BVCEO = 4.1 V. To the best of our knowledge, the present transistors are the first GaAsSb-based DHBTs to feature f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</sub> > 750 GHz. The progress in RF performance is enabled by a reduction of the base access resistance and base-collector capacitance achieved via an improved self-aligned emitter etching procedure.