Résumé
In this study, we present recent low frequency noise results obtained on Si/SiGe:C Heterojunction Bipolar Transistors (HBTs) associated with a 0.13 mu m BiCMOS technology. The HBTs are supplied by STMicroelectronics Crolles and present unity current gain frequencies (f(T)) and maximum oscillation frequencies (f(max)) in the 250s of GHz.
The 1/f noise sources are found to be located in the intrinsic emitter-base (E-B) region. The 1/f noise figure of merit, K-B, is found to be close to 1.5 10(-10) mu m(2). This excellent result is at least one decade better than the initial development of this 0.13 mu m BiCMOS technology. Moreover, in order to take into account the improvement of the high frequency parameters (f(T) and f(max)) associated to this technological evolution, we have studied the ratio f(c)/f(T), figure of merit that links LF Noise and transistor speed.
We have analyzed the 1/f noise improvement from different technological aspects related to the emitter-base process, for instance the surface cleaning (prior to the polysilicon deposition) and the epitaxial regrowth of the polysilicon.