New Insights Into Memory Window of Ferroelectric FET Impacted by Read Operations With Awareness of Polarization Switching Dynamics

In this article, the impacts of read operation under transient gate voltage sweep on the memory window (MW) of ferroelectric field-effect transistor (FeFET) are systematically investigated. By taking into consideration the polarization switching dynamics, it reveals a significant dependence on the sweep range and rate of gate voltage. With increasing sweep range, the increase of polarization switching leads to the monotonically increasing MW. However, different from sweep range, the MW of FeFET nonmonotonically varies with the increasing sweep rate, which is caused by the competition between decreased polarization switching and increased voltage drop on ferroelectric (FE) layer during forward sweep. Besides, compared with the MW obtained by pulsed gate voltage, it is found that the MW obtained by swept gate voltage can be the smaller one even without the consideration of charge trapping contribution. Furthermore, the impacts of FE switching time on MW are also discussed, indicating that the MW may not always be a constant even under quasi-static sweeping with low sweep rate, and the relationship between sweep rate of gate voltage and switching speed of FE plays a critical role in MW evaluation.