Nonvolatile Metal–Oxide–Semiconductor Capacitors with Ru-RuO_x Composite Nanodots Embedded in Atomic-Layer-Deposited Al₂O₃ Films

摘要

Growth of Ru-RuO _x composite nanodots (RONs) on atomic-layer-deposited Al₂O₃ films has been investigated using magnetic sputtering of a Ru target followed by postdeposition annealing. RONs with a density as high as ~2 × 1012 cm−2 were obtained together with good uniformity. Subsequently, metal–oxide–semiconductor capacitors with RONs embedded in Al₂O₃ films have been electrically characterized for different configurations of tunneling layers (T)/blocking layers (B), and the underlying mechanisms of charge storage are discussed. For a 6-nm T/22-nm B device, a memory window of 3.7 V is achieved for a ±7 V programing/erasing voltage for 0.1 ms, and superior charge retention of more than 80% is achieved after 10 years.