The influence of annealing on the capacitance-voltage characteristics of metal/SIPOS/silicon capacitors

Semi-insulating polycrystalline silicon (SIPOS)/Si samples have been annealed in forming gas at temperatures ranging from 300°C to 900°C. The influence of the anneal on the high frequency capacitance voltage characteristics of metal/SIPOS/silicon capacitors built afterwards has been studied. Up to annealing temperatures of 500°C, the rate of change of capacitance with voltage increases, while a decrease of this rate of change is observed at higher temperatures. Furthermore, the capacitance-voltage curves are shifted along the voltage axis towards more positive values up to 700°C. At higher annealing temperatures a shift in the opposite direction occurs.