M. Sanden et al., Lateral base design rules for optimized low-frequency noise of differentially grown SiGe heterojunction bipolar transistors, MICROEL REL, 41(6), 2001, pp. 881-886
The low-frequency noise dependence on lateral design parameters was investi
gated for SiGe heterojunction bipolar transistors fabricated by differentia
l epitaxy. The low-frequency noise was found to vary substantially as a fun
ction of the extrinsic base design. The dominant noise sources were located
either at the interface between the polycrystalline and epitaxial Si/SiGe
base, in the epitaxial Si/SiGe base link region, in the base-emitter deplet
ion region, or at the thin SiO2 interface layer between the polysilicon and
monosilicon emitter. Boron was found to passivate interfacial traps, actin
g as low-frequency noise sources. Generation-recombination noise with a str
ong dependence on the lateral electrical field was observed for some of the
designs. (C) 2001 Elsevier Science Ltd. All rights reserved.