Measurement and modelling of the emitter resistance of polysilicon emitter transistors

Abstract

A method for measuring the emitter resistance of polysilicon emitter transistors is described that separates the interface and metal/polysilicon contact components of the emitter resistance. Results show that for devices with a continuous interfacial layer the interface resistance controls the emitter resistance and is between 200 and 450 Omega mu m/sup 2/. This resistance is found to be current dependent and good agreement between theory and experiment is obtained. Results for devices with a discontinuous interfacial layer indicate that low interface resistances (17-33 Omega mu m/sup 2/) suitable for VLSI applications can be obtained by deliberately breaking up the interfacial layer. In this case the metal contact resistance contributes significantly to the total emitter resistance.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>