Study of Nanosecond Laser Annealing on Silicon Doped Hafnium Oxide Film Crystallization and Capacitor Reliability
Tarek Ali, Ricardo Olivo, S. Kerdilès, David Lehninger, Maximilian Lederer, D. Sourav, A-S. Royet, Ayse Sünbül, Aditya Prabhu, Kati Kühnel, M. Czernohorsky, Matthias Rudolph, Raik Hoffmann, C. Charpin-Nicolle, L. Grenouillet, Thomas Kämpfe, Konrad Seidel
Abstract
Study on the effect of nanosecond laser anneal (NLA) induced crystallization of ferroelectric (FE) Si-doped hafnium oxide (HSO) material is reported. The laser energy density (0.3 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 1.3 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and pulse count (1.0 to 30) variations are explored as pathways for the HSO based metal-ferroelectric-metal (MFM) capacitors. The increase in energy density shows transition toward ferroelectric film crystallization monitored by the remanent polarization (2P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</inf> ) and coercive field (2E <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ). The NLA conditions show maximum 2P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</inf> ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 24\ \mu\mathrm{C}/\text{cm}^{2}$</tex> ) comparable to the values obtained from reference rapid thermal processing (RTP). Reliability dependence in terms of fatigue (10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> cycles) of MFMs on NLA versus RTP crystallization anneal is highlighted. The NLA based MFMs shows improved fatigue cycling at high fields for the low energy densities compared to an RTP anneal. The maximum fatigue cycles to breakdown shows a characteristic dependence on the laser energy density and pulse count. Leakage current and dielectric breakdown of NLA based MFMs at the transition of amorphous to crystalline film state is reported. The role of NLA based anneal on ferroelectric film crystallization and MFM stack reliability is reported in reference with conventional RTP based anneal.