Temperature dependence of transient and steady-state gate currents in $HfO2$ capacitors

The authors investigated the temperature dependence of transient and steady-state gate currents in $HfO2$ capacitors from $300to75K$⁠. They show that transient currents measured on very thin $(5nm)$ $HfO2$ layers keep a power-law time dependence when temperature decreases to $75K$⁠, with only a small reduction in the current amplitude. Instead, the static gate leakage strongly decreases when temperature is reduced, also showing a change in the conduction mechanism. These results clearly demonstrate that transient currents in $HfO2$ dielectrics do not depend on the steady-state conduction mechanisms and are an issue that must be considered even at low temperatures.