Obtaining Lower Forming Voltage and Self-Compliance Current by Using a Nitride Gas/Indium-Tin Oxide Insulator in Resistive Random Access Memory

• Published in: IEEE transactions on electron devices Vol. 63; no. 12; pp. 4769 - 4775
• Main Authors: Po-Hsun Chen, Ting-Chang Chang, Kuan-Chang Chang, Tsung-Ming Tsai, Chih-Hung Pan, Chih-Cheng Shih, Cheng-Hsien Wu, Cheng-Chi Yang, Yu-Ting Su, Chih-Yang Lin, Yi-Ting Tseng, Min-Chen Chen, Ruey-Chi Wang, Ching-Chich Leu, Kai-Huang Chen, Ikai Lo, Jin-Cheng Zheng, Sze, Simon M.
• Format: Journal Article
• Language: English
• Published: IEEE 01.12.2016
• Subjects: Forming; Indium tin oxide; indium–tin oxide (ITO); insulator; Insulators; nitride gas (N2); Nitrogen; Random access memory; resistive random access memory (RRAM); Schottky diodes
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2016.2619704

This paper investigates the characteristics of applying indium-tin oxide (ITO) with and without nitride gas (N2) as the insulator in resistive random access memory (RRAM). After cosputtering an ITO target with N2 as the insulator and capping the same ITO material as the top electrode, the device exhibits rectifier and resistance switching characteristics before and after the forming process, respectively. The Schottky diodelike rectifier mechanism was also verified by various temperature measurements. Furthermore, robust resistance switching at a positive forming voltage, smaller than that required during negative bias forming, can be achieved. Both positive and negative forming processes are examined with current fitting results, which show different dominant mechanisms when using positive or negative biases. All these mechanisms have also been verified by temperature effect experiments, which confirmed the dominant conduction mechanisms. This, in combination with the fact that the positive forming voltage itself is smaller than the negative forming voltage, and decreases with device scale down, provides two highly beneficial results. This good performance achieved by using ITO with N2 suggests significant progress of RRAM and remarkable potential applications.