Characterization of neutral base recombination for SiGe HBTs

This paper, based on theoretical derivation of the expression for neutral base recombination (NBR) current, proposes a new characteristic parameter for NBR characterization and a method for estimating base minority-carrier lifetime for SiGe-base heterojunction bipolar transistors (HBTs). Furthermore, the proposed parameter is used to characterize the influence of NBR on the fabricated lightly base-doped SiGe and heavily base-doped SiGe:C HBTs. As a result, the base lifetimes are estimated to be around 2.0 and 0.10 ns for the SiGe and SiGe:C HBTs, respectively.