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

Abstract

Electroforming behaviours of Ta 2 O 5 resistance switching memory cell with a diameter of 28 nm and different thickness (0.5–2.0 nm) of Ta 2 O 5 layer have been examined. The devices showed a constant forming electric field of 0.54 V/nm regardless of Ta 2 O 5 thickness. 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 V O site to a nearby Ta site. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)