Thickness‐dependent electroforming behavior of ultra‐thin Ta2O5resistance switching layer

Electroforming behaviours of Ta2O5resistance switching memory cell with a diameter of 28 nm and different thickness (0.5–2.0 nm) of Ta2O5layer have been examined. The devices showed a constant forming electric field of 0.54 V/nm regardless of Ta2O5thickness. The electroforming with negative bias to top TiN electrode was ascribed to electric field‐ driven migration of oxygen vacancies, originally residing near the bottom interface, toward the top electrode interface and formation of conducting filaments. The estimated electroforming energy (0.094–0.14 eV) was favourably compared with the hopping energy of electrons from the VOsite to a nearby Ta site. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)