Authors: V.D. Kunz, C.H. de Groot, I.M. Anteney, A.I. Abdul-Rahim, S. Hall, P.L.F. Hemment, Y. Wang and P. Ashburn
Affilation: University of Southampton, United Kingdom
Pages: 16 - 19
Keywords: polySiGe emitter, bipolar transistor, gain control
In SiGe HBTs high values of fT are achieved by using aggressive Ge profiles in the base. A side effect is very high gains, which can lead to a degradation of BVCEO. This paper investigates Ge incorporation in polysilicon emitters to give gain control independent of the base Ge profile. A model is developed illustrating the reduced gain from Ge incorporation and increased gain from the interfacial oxide layer.