Compliance current and film thickness influence upon multi-level threshold resistive switching of amorphous BaTiO3 (am-BTO) films in Ag/am-BTO/Ag cross point structures

Highlights: • Stable threshold resistive switching is established in Ag/am-BaTiO₃/Ag cross-point structures. • Multi-level resistive switching depends upon compliance current and the thickness. • Oxygen vacancy mediated conduction channel is attributed to the switching. • Ohmic and space charge limited current conduction contributions are noted. -- Abstract: The influence of compliance current and film thickness upon multi-level threshold resistive switching characteristics of amorphous BaTiO₃ (am-BTO) thin films in Ag/am-BTO/Ag cross point structures have been investigated. The cross-point junctions are fabricated utilizing RF/DC magnetron sputtering technique and the thickness of am-BTO films are tuned with the sputtering time. The structural and microstructural details are probed with X-ray diffraction, Atomic force microscopy, Field effect scanning electron microscopy and X-ray photoelectron spectroscopy techniques. The current-voltage characteristics revealed a stable threshold resistive switching with maximum I_ON/I_OFF ratios of ~ 2 × 10³ with low-threshold voltages and near zero voltage hold values are noted for 142 nm am-BTO thin film at 1 × 10⁻⁴ A compliance current. The compliance current found to affect the bi-stability or multi-level resistance switching. The contribution of oxygen vacancies to the switching is elucidated from X-ray photoelectron spectroscopy measurements. Furthermore, the thickness effect on threshold resistive switching properties along with conduction mechanisms in lower and higher resistance states are discussed.