New Understanding of Screen Radius and Re-evaluation of Memory Window in Cylindrical Ferroelectric Capacitor for High-density 1T1C FeRAM

In this work, the electrical characteristic and its physics of the 3D cylindrical ferroelectric capacitor (FeCAP) are investigated for high-density 1T1C FeRAM based on a proposed novel simulation method. Different from planar FeCAP, it is found that an intrinsic polarization loss exists in cylindrical FeCAP for low voltage operation. Besides, there is a screen cylinder surface inside the cylindrical FeCAP under zero bias. Moreover, a novel method for accurately evaluating memory window of 3D FeCAP is proposed based on the screen surface, showing a significant overestimation by conventional method (similar to 44%). Based on the proposed method, it is shown that the geometric parameters optimization should be compromised for the maximum storage density.