Ten-Nanometer Ferroelectric \hbox Films for Next-Generation FRAM Capacitors

• Published in: IEEE electron device letters Vol. 33; no. 9; pp. 1300 - 1302
• Main Authors: Mueller, S., Summerfelt, S. R., Muller, J., Schroeder, U., Mikolajick, T.
• Format: Journal Article
• Language: English
• Published: IEEE 01.09.2012
• Subjects: Capacitors; Degradation; Doped hbox{HfO}_{2}; ferroelectric hbox{HfO}_{2}; ferroelectric random access memory (FRAM); ferroelectric thin films; Hafnium compounds; Nonvolatile memory; nucleation-limited switching (NLS); Random access memory; Switches; Temperature measurement
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2012.2204856

Ferroelectric properties of Si-doped HfO 2 thin 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 10 6 programming and erase cycles at 3 V.