Implementation Of Multiple Hbt Variants In 018 Micron Silicon Germanide Bicmos Technology

The SiGe BiCMOS technology is the cost-effective solution for high-speed communications applications due to its RF/analog properties and CMOS compatibility. The main challenge with the optimization of SiGe HBT is to achieve both high speed and high breakdown performance simultaneously. This thesis investigates the optimization of the collector profile to attain multiple variants of SiGe HBTs, namely high speed, standard and high voltage devices, in one BiCMOS technology. Using process and device simulations, the device performance is enhanced by base and collector profile optimization to minimize base transit time and collector delay. Variants of SiGe HBTs with multiple cutoff frequencies and breakdown voltages are achieved by proper choice of collector doping concentration using selectively-implanted collectors (SIC). Three SiGe npn transistors with fT/BVCEO values of 80GHz/2V, 60GHz/2.9V and 40GHz/4.8V are successfully fabricated in standard 0.18 mum CMOS technology by an industrial foundry, with minimal extra process complexity.