Different Directions of Switching of Chromium Oxide Thin Films

作者：Ngoc Kim Pham^*; Do Trung Nguyen; Bang Tam Thi Dao; Kieu Hanh Thi Ta; Vinh Cao Tran; Van Hieu Nguyen; Kim Sang Sub; Maenosono Shinya; Thang Bach Phan

来源：Journal of Electronic Materials, 2014, 43(7): 2747-2753.

DOI：10.1007/s11664-014-3193-3

• Chromium oxide
• resistance switching
• grain boundaries
• electrochemical redox reactions
• oxygen ion migration

We have investigated the switching behavior of as-deposited CrO (x) and post-annealed CrO (y) films by use of a variety of electrodes (top electrode Ag, Ti; bottom electrode Pt, fluorine tin oxide (FTO)). Resistance switching is highly dependent on electrode material and post-annealing treatment. Among Pt devices, I-V hysteresis was observed for the Ag/CrO (x) /Pt device only; no resistance switching was observed for Ag/CrO (y) /Pt, Ti/CrO (x) /Pt, and Ti/CrO (y) /Pt devices. Among FTO devices, I-V hysteresis was observed for the Ag/CrO (x) /FTO device whereas I-V hysteresis with the opposite switching direction was observed for Ag/CrO (y) /FTO, Ti/CrO (x) /FTO, and Ti/CrO (y) /FTO devices. The direction of switching depends not only on electrode material but also on post-annealing treatment, which affects the density of grain boundaries. Thus, the density of grain boundaries determines the type of charge carrier involved in the switching process. For as-deposited CrO (x) films with a high density of grain boundaries Ag filament paths mediated by electrochemical redox reaction were observed, irrespective of bottom electrode material (Pt or FTO). Post-annealed CrO (y) films with a low density of grain boundaries suppressed electrochemical redox reaction in the Ag/CrO (y) /Pt device but promoted short-range movement of O2- ions through the bottom interface, resulting in resistance switching in the Ag/CrO (y) /FTO device. Electrochemical redox reaction-controlled resistance switching occurred solely in oxides with a high density of grain boundaries or dislocations.

• 出版日期2014-7