FeRAM using Anti-ferroelectric Capacitors for High-speed and High-density Embedded Memory
Sou-Chi Chang, N. Haratipour, S. Shivaraman, C. Neumann, S. Atanasov, J. Peck, N. Kabir, I. -C. Tung, H. Liu, B. Krist, A. Oni, S. Sung, B. Doyle, G. Allen, C. Engel, A. Roy, T. Hoff, Hai Li, Fatih Hamzaoglu, R. Bristol, M. Radosavljevic, B. Turkot, M. Metz, Ian A. Young, J. Kavalieros, U. Avci
Abstract
This paper demonstrates industry-best hafnium-based FeRAM performance and reliability by showing (i) read/write speed scaled down to ~2ns, (ii) read/write endurance beyond 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cycles, and (iii) tail-bit variations of scaled capacitors working at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4\sigma$</tex> across a 300mm wafer at elevated temperature, by switching anti-ferroelectric (AFE) capacitors at −1.6V and 1.2V. Furthermore, a physics-based multi-domain compact circuit model is developed for AFE capacitors to describe FeRAM operations. Array-level circuit simulations show that FeRAM is less vulnerable to disturb through parasitic capacitor coupling due to the small amount of polarization charge change <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\Delta P)$</tex> relative to its high remanent polarization <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(P_{r})$</tex> . Finally, high yield in a capacitor-array with no significant degradation in retention well over 10s and a healthy memory window (MW) under 1ms disturb 20% of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$V_{write}$</tex> at elevated temperature is shown, paving way for AFE-based FeRAM toward the next generation high-speed and high-density embedded memory.