Simultaneous optimization of doping profile and Ge-dose in base in SiGe HBTs

This work presents an approach to optimize the base doping and Ge-dose inside the base of SiGe HBTs using the fixed point iterative methodology and includes the effect of minority carrier velocity saturation on total base transit time for SiGe HBTs. It is shown that shifted-Ge approach and linear Ge-profile in base can lead to simultaneous optimization of Ge-dose and base dopant distribution for minimum base transit time.