Admittance of metal-insulator-semiconductor tunnel contacts in the presence of donor-acceptor mixed interface states and interface reaction

The admittance of a metal-insulator-semiconductor tunnel contact is evaluated considering the presence of donor-acceptor mixed interface states and chemical reaction in the interfacial oxide layer. Both the voltage and frequency behavior of the device has been studied. It has been found that, due to interface reaction, the current, conductance, and capacitance of the device drift considerably with time yielding an aging effect. Further, it is revealed that the dependence of the conductance and capacitance on the aging time stem rapidly from changing time constants of the interface states with aging time. The results are discussed with special reference to well known admittance spectroscopy used for the characterization of interface states. (C) 2001 American Institute of Physics.