Transient Negative Capacitance Induced by Charged Oxygen Vacancy Drift in HfO2‐Based Films

Abstract

Transient negative capacitance (TNC) is believed to be the key for understanding and harnessing quasistatic negative capacitance in HfO2‐based films which offers a promising solution for low‐power‐dissipation electronics, but the physical picture is still under debate. Herein, a model based on charged oxygen vacancy (VO) drift is proposed to interpret the TNC effect. The results show that TNC possibly originates from the mismatch between the charged VO drift and the compensation charge supply from external source. The model captures the main features of experimental observations, including the enhancement of both TNC voltage window and duration time with increasing series resistance. Moreover, negative slopes appear in the charge–voltage curves, without invoking the Landau–Khalatnikov scenario. It is revealed that TNC is only observable within a rather narrow charged VO concentration window near 5 × 1019 cm−3. The model manifests itself by the fact that most of the HfO2‐related films in the TNC studies are treated under nitrogen atmosphere and therefore, are oxygen deficient.