Key points are not available for this paper at this time.
This paper reports on SiGe NPN HBTs with unity gain cutoff frequency (f T ) of 207 GHz and an f max extrapolated from Mason's unilateral gain of 285 GHz. f max extrapolated from maximum available gain is 194 GHz. Transistors sized 0.12×2.5 μm 2 have these characteristics at a linear current of 1.0 mA/μm (8.3 mA/μm 2 ). Smaller transistors (0.12×0.5 μm 2 ) have an f T of 180 GHz at 800 μA current. The devices have a pinched base sheet resistance of 2.5 k/spl Omega//sq. and an open-base breakdown voltage BV/sub CEO/ of 1.7 V. The improved performance is a result of a new self-aligned device structure that minimizes parasitic resistance and capacitance without affecting f T at small lateral dimensions.
Jagannathan et al. (Wed,) studied this question.