Test structure for investigating activated doping concentrations in polycrystalline silicon

A new method for evaluating the active doping concentration in polycrystalline silicon (polysilicon) using a double polysilicon capacitor test structure is described. The technique is based upon the measured and theoretical capacitance-voltage characteristics of the structure. The results can provide further insight into the effect of depletion into the polysilicon gate of MOSFETs, as well as the effects of dopant redistribution in polysilicon/silicide bilayers used in sub-micron CMOS silicidation schemes.