Collector optimization for tradeoff between breakdown voltage and cut-off frequency in SiGe HBT

作者：Qiang Fu, Wanrong Zhang, Dongyue Jin, Chunbao Ding, Yanxiao Zhao, Lu Dong · 发表于：Chinese Physics B · 年份：2014 · DOI：10.1088/1674-1056/23/11/114402 · 被引用次数：6 · 研究领域：Radio Frequency Integrated Circuit Design、Advancements in Semiconductor Devices and Circuit Design、Semiconductor Quantum Structures and Devices

As is well known, there exists a tradeoff between the breakdown voltage BV CEO and the cut-off frequency f T for a standard heterojunction bipolar transistor (HBT). In this paper, this tradeoff is alleviated by collector doping engineering in the SiGe HBT by utilizing a novel composite of P + and N − doping layers inside the collector-base (CB) space-charge region (SCR). Compared with the single N-type collector, the introduction of the thin P + layers provides a reverse electric field weakening the electric field near the CB metallurgical junction without changing the field direction, and the thin N − layer further effectively lowers the electric field near the CB metallurgical junction. As a result, the electron temperature near the CB metallurgical junction is lowered, consequently suppressing the impact ionization, thus BV CEO is improved with a slight degradation in f T . The results show that the product of f T × BV CEO is improved from 309.51 GHz·V to 326.35 GHz·V.