Geometric and Area Scaling Effects on Ferroelectric Properties of Al0.8Sc0.2N-Based Capacitive Memory

초록

In this letter, we investigate the geometric and area dependence of ferroelectric behavior in Al0.8Sc0.2N-based metal-ferroelectric-metal capacitors. Circular and square top electrodes with areas ranging from 707 to 2,500 & micro;m(2) are employed to examine the influence of electrode geometry on polarization switching, dielectric response, and reliability. As the electrode area decreases, the apparent remnant polarization and measured dielectric constant increases from 80 to 97 & micro;C/cm(2) and 17.1 to 19.7. This scaling trend is associated with the periphery-to-area ratio rather than intrinsic material changes. Smaller electrodes exhibit higher peak switching current densities (up to 48.7 A/cm(2)), indicating enhanced switching near the electrode edges. The coercive field (E-C) shows shape-dependent trends: square electrodes exhibit higher E(C)at smaller sizes due to corner-induced non-uniformity, whereas circular electrodes show increased E(C)at larger areas. Retention and endurance measurements demonstrate stable operation across all geometries, with a wake-up effect observed during cycling. Finite-element simulations indicate that the observed scaling behavior originates from localized electric-field enhancement near the electrode perimeter. These results emphasize the role of electrode geometry on the apparent scaling behavior of Al0.8Sc0.2N ferroelectric capacitors.

키워드