600 GHz InP/GaAsSb/InP DHBTs Grown by MOCVD with a Ga(As,Sb) Graded-Base and f<sub>T</sub> x BV<sub>CEO</sub> ≫ 2.5 THz-V at Room Temperature

Abstract

We describe the realization of ternary base InP/Ga(As,Sb) DHBTs, where the grading is implemented by ramping the base As/Sb composition ratio from the collector to the emitter side: this enables a cutoff frequency f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> of 603 GHz at room temperature with a breakdown voltage BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CEO</sub> = 4.2 V, for a record f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> xBV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CEO</sub> product of 2.53 THz-V. Device performance improves further with cooling to reach f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ≫ 700 GHz with BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CEO</sub> = 4.4 V at 5K. To the best of our knowledge, this represents the highest f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ever reported for a DHBT of any kind. The f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> xBV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CEO</sub> ≫ 3.10 THz-V at 5 K is also unprecedented.