Superior unipolar resistive switching in stacked ZrOx/ZrO2/ZrOx structure

• Published in: AIP advances Vol. 6; no. 3; pp. 035103 - 035103-15
• Main Authors: Lin, Cheng-Li, Lin, Tse-Yu
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01-03-2016; AIP Publishing LLC
• Subjects: Capping; Control stability; Low resistance; Oxidation; Oxygen content; Oxygen ions; Recovery; Stability; Switching; Thickness; Variations; Zirconium dioxide
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.4943508

This study investigates the performance of unipolar-switched ZrO2 RRAM, using an oxygen-deficient and amorphous ZrOx capping in a sandwich stack Al/ZrOx/ZrO2/ZrOx/Al structure. Superior high and low resistance switching and a resistance ratio (HRS/LRS) greater than 10 showed excellent dc endurance of 7378 switching cycles and 3.8 × 104 cycles in pulse switching measurements. Recovery behavior, observed in the I-V curve for the SET process (or HRS), led to HRS fluctuations and instability. A new resistance switching model for the stacked ZrO2 RRAM is proposed in this paper. In this model, oxygen-deficient and amorphous ZrOx film, capped on polycrystalline ZrO2 film, plays a key role and acts as an oxygen reservoir in making the oxygen ions redox easily for the SET process and in facilitating re-oxidation for the RESET process, resulting in excellent endurance. By improving the stability and recovery phenomena, engineering parameters of the current control may play a critical role during switching, and they can be correlated to the film’s thickness and the oxygen content of the amorphous ZrOx film.