Stochasticity in ferroelectric memory devices with different bottom electrode crystallinity

Abstract

This study comprehensively analyzes of the influence of bottom electrode crystallinity on the stochastic noise in ferroelectric tunnel junctions (FTJs). We perform a comparative analysis of stochastic read noise in FTJ devices with crystalline silicon (FTJc-Si) c-Si ) and poly-silicon (FTJ poly-Si ) bottom electrodes by utilizing low-frequency noise spectroscopy and multi-frequency conductance measurements. The results indicate that FTJ poly-Si exhibits a 50 % higher read current fluctuation in the high-resistance state (HRS) at high read currents compared to FTJ c-Si due to differences in interface trap density and the subsequent barrier height fluctuations. Although the crystallinity of the bottom electrode affects the noise in the HRS, the noise in the low-resistance state (LRS) remains consistent with the consequence of bulk-limited Poole-Frenkel emission. These findings clarify the relationship between bottom electrode crystallinity and stochastic noise in FTJs, providing crucial insights for the design and operation of future ferroelectric-based memory.