Investigation of f T -Doubler Technique to Improve RF Performance of Inverse-Mode SiGe HBTs

• Published in: IEEE microwave and wireless components letters 2020-09, Vol.30 (9), p.873-875
• Main Authors: Sarker, Md Arifur R., Omprakash, Anup P., Cho, Moon-Kyu, Cressler, John D., Song, Ickhyun
• Format: Article
• Language: English
• Subjects: Circuit design; Emitters; Germanium; Heterojunction bipolar transistors; Semiconductor devices; Silicon germanides
• ISSN: 1531-1309; 2771-957X; 1558-1764; 2771-9588
• DOI: 10.1109/LMWC.2020.3010538

This letter presents the application of the [Formula Omitted]-doubler technique, for the first time, to improve the unity-gain frequency [Formula Omitted] of inverse-mode (IM) silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs). An [Formula Omitted]-doubler structure, which used three identical SiGe HBTs with the same emitter area of 0.07 (width) [Formula Omitted] (length) [Formula Omitted], is implemented in a commercial 0.13-[Formula Omitted] SiGe-BiCMOS technology platform. A peak [Formula Omitted] of 77 GHz is extrapolated for the IM [Formula Omitted] doubler, whereas a peak [Formula Omitted] of a single IM SiGe HBT is found to be 53 GHz, exhibiting an increase of about 46% in [Formula Omitted] from the [Formula Omitted]-doubler technique. The maximum oscillation frequency of the IM [Formula Omitted] doubler using Mason’s unilateral gain is about 158 GHz. In addition, small-signal model parameters of the IM [Formula Omitted] doubler are presented, which show the IM [Formula Omitted]-doubler structures can be treated as a single transistor element for high-frequency circuit design.