Electronic Materials Letters , vol. 4, no. 1, pp.29-33, March, 2008

DOI :

Resistive Switching Properties of Pt/TiO₂/n⁺-Si ReRAM for Nonvolatile Memory Application

Sanghee Won, Seunghee Go, Kwanwoo Lee, and Jaegab Lee^*
Kookmin University

Abstract : We fabricated sputter-Pt/atomic layer deposition (ALD) TiO₂/n⁺-Si structures for resistive random access memory (ReRAM). The use of n⁺-Si bottom electrode provides a simple way of fabricating ReRAMs, and offers compatibility with the conventional CMOS process. After annealing Pt (100 nm)/ ALD TiO₂(38 nm)/ n⁺-Si structures in an O₂ ambient at a temperature range of 100 to 500°C, we examined their effects on the switching properties. The as-deposited ALD TiO₂ thin films showed no switching behavior. However, annealing at 100°C enabled the thin films to switch between a low- resistance state and a high-resistance state, thereby revealing the resistive switching behavior. In addition, electric pulse-induced resistance switching was repeated (about twenty times) in the 100°C-annealed TiO₂ films. When the annealing temperature was increased to 300°C, the switching properties of the TiO₂ thin films were significantly improved in terms of the resistive switching cycle and the dispersion of the set/reset voltages, probably due to the improved crystallization of the TiO₂ films and the enhanced anode interface properties. As a result, the simple structure of Pt/ALD TiO₂/n⁺-Si can be applied to nonvolatile memory devices.

Keyword : TiO₂, resistive switching, memory effects