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 300 to 75 K. They show that transient currents measured on very thin (5 nm) HfO₂ layers keep a power-law time dependence when temperature decreases to 75 K, 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.