Base region optimization of SiGe HBTs for high-frequency microwave power amplification

The base region optimization of SiGe power HBTs for high frequency power amplification is investigated. Employing a heavily doped base in conjunction with a high Ge content can effectively improve the large-signal power gain values of SiGe HBTs while maintaining their high breakdown voltages and thus allow them to be efficiently operated with high power at higher frequencies. With such a base region optimization, not only lateral scaling requirement can be relaxed, but also common-base configuration for power amplification using these devices can be favored, which further enhances power gain values of SiGe power HBTs at high frequencies. Load-pull experimental results are presented to show the highest figure of merit power performance of SiGe power HBTs with an optimized base region. Power performance at X-band with different base region designs was also compared to illustrate the significant benefits that are resulted from base optimization.