Ten-Nanometer Ferroelectric $\hbox{Si:HfO}_{2}$ Films for Next-Generation FRAM Capacitors

Ferroelectric properties of Si-doped HfO2thin films (10 nm) have been investigated. The focus of this letter is to evaluate the potential applicability of these thin films for future 3-D ferroelectric random access memory capacitors. Polarization switching was tested at elevated temperatures up to 185°C and showed no severe degradation. Domain switching dynamics were electrically characterized with pulse-switching tests and were not in accordance with Kolmogorov-Avrami-type switching. Nucleation-limited switching is proposed to be applicable for these new types of ferroelectric thin films. Furthermore, same-state and opposite-state retention tests were performed at 125°C up to 20 h. It was found that samples that had previously been annealed at 800°C showed improved retention of the written state as well as of the opposite state. In addition, fatigue measurements were carried out, and no degradation occurred for 106programming and erase cycles at 3 V.