First Observation of Ultra-high Polarization (~ 108 μC/cm²) in Nanometer Scaled High Performance Ferroelectric HZO Capacitors with Mo Electrodes
Fei Huang, Balreen Saini, L. Wan, Haidong Lu, Xiao He, S. Qin, Wilman Tsai, Alexei Gruverman, Andrew C. Meng, H.‐S. Philip Wong, Paul C. McIntyre, S.S. Wong
Abstract
We demonstrate, for the first time, excellent ferroelectricity, and endurance of 4 nm-thick and $65\mathrm{~nm}\times 45\mathrm{~nm}$ size Hf <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf> Zr <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (HZO) capacitors with Mo electrodes. We show 1) the crystallization temperature is as low as 400 °C, which is critical for BEOL FeRAM; 2) benefits from thickness scaling, low operation voltage (1.2 V) and high endurance (>10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> cycles) are achieved; 3) the wake-up effect is further reduced to 20% and the beginning of fatigue is delayed by an order of magnitude by adding a 1 nm CeO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> stressor layer; and 4) direct measurements of ferroelectricity with ultra-high polarization switching $(\sim 108 \mu\mathrm{C}/\mathrm{cm}^{2})$ in devices scaled down to $95\mathrm{~nm}\times 85\mathrm{~nm}$ size. This study advances the understanding of scaling effect in HZO capacitors.