Resistance Switching Peculiarities in Nonfilamentary Self‐Rectified TiN/Ta<sub>2</sub>O<sub>5</sub>/Ta and TiN/HfO<sub>2</sub>/Ta<sub>2</sub>O<sub>5</sub>/Ta Stacks
Dmitry S. Kuzmichev, Аnna G. Chernikova, Maxim G. Kozodaev, Andrey M. Markeev
Abstract
Herein, Ta 2 O 5 /Ta interface‐based TiN/Ta 2 O 5 /Ta and TiN/HfO 2 /Ta 2 O 5 /Ta resistance switched (RS) stacks are investigated. The stacks reveal area‐dependent RS behavior indicating nonfilamentary (homogeneous) current transport. The nonfilamentary nature of the stacks provides high reproducibility of current–voltage hysteresis loops and the absence of electroforming. It is demonstrated that the nature of the current hysteresis in single Ta 2 O 5 ‐based stacks obeys space‐charge‐limited conduction, and the space charge responsible for this behavior is formed by filled/emptied traps at the Ta/Ta 2 O 5 interface. Due to the high potential barrier at the TiN/HfO 2 interface, as measured using X‐ray photoelectron spectroscopy, sufficiently thick HfO 2 (≈4 nm) blocks the trapping/detrapping process, thereby reducing the current hysteresis. The evaluated current mechanism results in a high rectification ratio of the TiN/Ta 2 O 5 /Ta device of ≈1.6 × 10 4 . However, relatively short retention is inherent to the observed switching mechanism.