Rewritable Capacitance Disk Memory with Ferroelectric-Semiconductor Structure

This paper presents a new rewritable capacitance disk memory with a ferroelectric-semiconductor structure. The ferroelectric film of the medium was poled in the perpendicular direction to generate depletion capacitance for data recording. Capacitance between the stylus head and the medium was detected for data reproduction. The amount of change in capacitance due to the poling direction showed that the recording density of this memory system could be more than 1 Gbit/cm 2 . Evaluation equipment was constructed for dynamic bit recording and reproduction, in which the mobile stylus head was in contact with the medium surface. It was confirmed that data bits with 0.4 µm spatial wavelength could be recorded and reproduced. In our experiment, recording density was mostly determined by the stylus size, and its limit was also estimated by the numerical simulation of ferroelectric semiconductor structure.