Determination of generation lifetime in intrinsic polycrystalline silicon

A simple two-terminal method is described for the determination of generation lifetime in intrinsic polycrystalline silicon suitable for thin-film transistor applications using a metal/SiO2 /polycrystalline silicon/n-type silicon test structure. The method consists of monitoring the high-frequency capacitance of the test structure after the application of a voltage pulse of the correct polarity to cause deep depletion in the n-type substrate. Generation lifetimes of 34 ps to 19 ns are obtained for polycrystalline silicon films of varying grain size.