Characterization of the Emitter Contact in Poly-emitter Bipolar Transistors for Extraction of the Series Emitter Resistance

The nonohmic behavior of the emitter contact in bipolar transistors employing polysilicon emitters has been characterized based on an improved open collector method. Fowler-Nordheim tunneling through a triangular potential barrier is ruled out as the dominant transport mechanism at the polysilicon-emitter interface. A subcircuit-based model explaining the effect of substrate bias on the behavior of the series emitter resistance is evaluated for circuit simulation. Finally, extraction of the emitter resistance in presence of nonlinearity associated with transport at the emitter interface is discussed.

Keywords:

Heterojunction bipolar transistor , interfacial oxide , nonlinear transport , polysilicon emitter , series emitter resistance.