High deposition rate hydrogenated polymorphous silicon characterized by different capacitance techniques

High deposition rate hydrogenated polymorphous silicon thin films were analyzed using different capacitance techniques. The distribution of localized states and some electrical properties were studied by the temperature, frequency and bias dependence of the Schottky barrier capacitance and deep level transient spectroscopy. Our different samples present different groups of gap states depending on the preparation conditions. A comparison with standard amorphous silicon films reveals a reduced density of states in the gap for high deposition rate samples. Our results show that the samples, which represent only one group of gap states and lower density of states in the gap, were the samples grown at deposition rate of 8 Å/s.