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

Al-rich
$\hbox{Al}_{2}\hbox{O}_{3}$
thin films are synthesized by radio-frequency magnetron sputtering, followed by thermal annealing at 500
$^{\circ}\hbox{C}$
for different durations to form Al/Al-rich
$\hbox{Al}_{2}\hbox{O}_{3}/p\hbox{-Si}$
diodes. The annealing causes reactions at the Al-rich
$\hbox{Al}_{2}\hbox{O}_{3}/\hbox{Si}$
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
$\hbox{Al}_{2}\hbox{O}_{3}$
layer extracted from the
$C$
–
$V$
reconstruction shows power-law voltage dependence correlated with the current-conduction measurement.