Understanding the memory window in 1T-FeFET memories: a depolarization field perspective

摘要

We present a physics-based prediction of the progressive VTH shift on fabricated Si:HfO2-FeFETs during Incremental Step Pulse Programming, with the help of our in-house, hardware-validated FeFET compact model. Our study confirms that the depolarization field across the FE layer strongly constrains the retained polarization in the gate stack after the programming waveform stops, which constitutes a fundamental, self-limiting effect on the attainable memory window in multidomain FeFETs. An extensive sensitivity study based on the model suggests that for a 9.5 nm-thick FE layer, decreasing the mean negative coercive field from −1.0 MV/cm to −1.5 MV/cm improves the MW from 0.75 V to 1.07 V, thus effectively alleviating detrimental impact of the depolarization field.