Pseudomorphic InP/InGaAs Heterojunction Bipolar Transistors (PHBTs) Experimentally Demonstrating f<sub>T</sub> = 765 GHz at 25°C Increasing to f<sub>T</sub> = 845 GHz at -55°C

Abstract

Pseudomorphic InP HBTs (PHBTs) with a vertically scaled design implementing a 12.5 nm base and 55 nm collector exhibit record current gain cutoff frequency performance of f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> =765 GHz when measured at 25°C. When cooled to -55°C, f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> improves more than 10% to f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> =845 GHz due to enhanced electron transport and reduced parasitic charging delays as determined by small signal equivalent circuit parameter extraction. Peak performance current density J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> =18.7 mA/μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CEO</sub> =1.65 V