Annealing-Induced Changes in Electrical Characteristics of Al/Al-Rich $\hbox {Al}_{2}\hbox {O}_{3}/p\hbox {-Si}$ Diodes

Al-rich thin films are synthesized by radio-frequency magnetron sputtering, followed by thermal annealing at 500°C for different durations to form Al/Al-rich diodes. The annealing causes reactions at the Al-rich interface, leading to an increase in Al concentration in the interface region. As a result, the current conduction of the diode is significantly enhanced, which results in anomalous capacitance-voltage (C-V) characteristics. The anomalous behaviors can be eliminated by reconstructing the C-V curve based on a four-element circuit model. The resistance of the Al-rich layer extracted from the C-V reconstruction shows power-law voltage dependence correlated with the current-conduction measurement.