An Empirical Investigation on the Effect of Oxygen Vacancy in ZrO2 Thin Film on the Frequency-Dependent Capacitance Degradation in the Metal–Insulator–Metal Capacitor

The operation speed of dynamic random access memory devices has been increasing with respect to the evolution of electronic devices. This in turn has induced a decrease in the allowed time for the operation. Therefore, the effective capacitance degradation in which the capacitance gradually decreases with increasing frequency of applied ac voltage is a severe concern for decreasing capacitance during fast operation, in addition to inducing reliability degradation. Hence, in this article, the origin of capacitance degradation depending on operation frequency, also called "frequency dependence" of the capacitance, was revealed. By performing dc and ac nonlinearity analyses, the effect of defects, especially oxygen vacancies, on the electrical properties of metal-insulator-metal (MIM) capacitors was investigated. Eventually, the mechanism of frequency dependence related to oxygen vacancy in the insulator of the MIM capacitor was identified.