Low-frequency noise in modern bipolar transistors: impact of intrinsic transistor and parasitic series resistances

In modern submicrometer transistors, the influence of the internal base and emitter series resistances, on both the I-V characteristics and the LF noise at higher bias currents, becomes important. In this paper expressions are presented for the LF noise in transistors, where the influence of the series resistances has been taken into account. The expressions have been compared with recent experimental results from the literature obtained from modern submicrometer (heterojunction) bipolar transistors. At low forward currents the LF noise in such transistors is determined by spontaneous fluctuations in the base and collector currents. In most transistors at higher forward currents, the parasitic series resistances and their noise become important