Low-frequency noise in single–poly bipolar transistors at low base current density

This paper deals with the low-frequency noise of single–poly bipolar transistors (SBJT) biased at low base current density. From Gummel plots and low-frequency noise measurements performed on many SBJTs made using the same process, it is clearly demonstrated that the low-frequency noise is related to generation–recombination mechanisms (GR) that occur at the periphery of the emitter–base space charge region. A model which takes into account both the diffusion noise and the GR noise is proposed. A comparison with some measurements performed on another BiCMOS technology and with some results of the literature validates this analysis.