Forming Free Bipolar ReRAM of Ag/a-IGZO/Pt with Improved Resistive Switching Uniformity Through Controlling Oxygen Partial Pressure

• Published in: Journal of electronic materials 2015-02, Vol.44 (2), p.645-650
• Main Authors: Pei, Yanli, Mai, Biaoren, Zhang, Xiaoke, Hu, Ruiqin, Li, Ya, Chen, Zimin, Fan, Bingfeng, Liang, Jun, Wang, Gang
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics and Microelectronics; Instrumentation; Materials Science; Optical and Electronic Materials; Oxygen; Pressure; Random access memory; Solid State Physics; Switching
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-014-3547-x

Bipolar resistive switching properties of Ag/a-IGZO/Pt structure resistive random-access memories (ReRAMs) were investigated. The amorphous In-Ga-Zn-O (a-IGZO) films were prepared by a radio frequency magnetron sputtering system at room temperature in mixed gas ambient of argon (Ar) and oxygen (O 2 ). The oxygen partial pressures during sputtering deposition were varied from 0% to 17% to engineer defects in an a-IGZO layer. When the oxygen partial pressure increased to 17%, forming-free bipolar resistive switching properties were observed with nearly 100% device yield. In addition, the forming-free ReRAM device presents an enhanced resistive switching uniformity and an enhanced endurance. The forming-free resistive switching is attributed to the concentration of oxygen-related defects in an a-IGZO thin film via analyses of x-ray photoelectron spectroscopy and current–voltage ( I – V ) curves, with which it is possible to reduce the forming energy of silver (Ag) conductive filaments.