Effect of collector lateral scaling on performance of high-speed SiGe HBTs with f_T>300GHz

The effect of collector lateral scaling on the performance of 300GHz-level SiGe HBTs is investigated. Peak fT and fmax exhibited an initial improvement followed by a degradation with decreasing collector width. Possible causes behind the observed trend are discussed in terms of RC delay and the Kirk effect. © The Institution of Engineering and Technology 2006.