BEOL-Compatible Multiple Metal-Ferroelectric-Metal (m-MFM) FETs Designed for Low Voltage (2.5 V), High Density, and Excellent Reliability

Abstract

An experiment-calibrated SPICE model considering dynamic ferroelectric switching and charge injection is established to co-optimize memory window, write speed, endurance, and retention of MFMFET where a standard BEOL HfZrOx MFM capacitor is stacked on top of the logic transistor. This promising SOC-compatible, low-power and low-voltage embedded memory achieves a high current on-off ratio > 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> when programming at ±2.5 V for 3 μs without compromising 10-year retention and MFM-equivalent endurance. A novel m-MFMFET utilizing multiple MFMs is also proposed. m-MFMFET achieves equivalent performance as the standard MFMFET but further reduces the unit cell size by 22 %.