100-nm lateral size ferroelectric memory cells fabricated by electron-beam direct writing

A fundamental limitation in the recent development of non-volatile ferroelectric memories of 64-Mbit to 4-Gbit densities was found to be the problem to scale ferroelectric capacitor cell sizes down below 1 μm2. In this paper we report on the preparation of ferroelectric memory cells with lateral sizes down to 100 nm using electron-beam direct writing. Switching of single 100-nm cells was achieved and piezoelectric hysteresis loops were recorded using a scanning force microscope working in piezoresponse mode. The piezoelectricity and its hysteresis acquired for 100-nm PZT cells demonstrate that a further decrease in lateral size under 100 nm appears to be possible and that the size effects do not fundamentally limit the increase of the density of non-volatile ferroelectric memories in the Gbit range.