Impact of Non-Uniform Ferroelectric Dielectric Phase and Metal Grains on the Performance of MFM Capacitor and Ferroelectric FETs

Reliability and yield are major concerns for memory devices. The random variability sources have a significant impact on the reliability of the memory window (MW) in ferroelectric FETs. In this work, through a comprehensive study, we analysed the impact of the non-uniform dielectric phase and metal grains on the coercive field of Metal-Ferro-Metal capacitor and on the performance of FeFETs. We found 1) Metal grains randomization (MGR) causes polarization non-uniformity throughout the volume of the ferroelectric layer; 2) Smaller metal thickness (Tmetal) causes larger polarization non-uniformity due to work function discreteness. It leads to higher device variability and results in memory window closure; 3) Larger the metal grain size (MGS) higher will be the device variation; 4) The combination of higher the DE phase along with the higher DE grain size and larger the MGS with Tmetal causes worst-case reliability issues.