Crowding effects and low frequency noise in polysilicon emitter bipolar transistors

This note explores experimentally the limitations of the lumped parameter m odel of polysilicon emitter junction transistors (BJT) in low frequency noi se (1/f noise) analysis. Deviations from the lumped model were clearly obse rved experimentally in BJT when determining the base current fluctuations r esulting from minority carriers crossing the emitter monosilicon-polysilico n oxide layer. We apply a distributed model of the base access resistance t aking into account crowding effects to explain our experimental results. (C ) 1999 Elsevier Science Ltd. All rights reserved.