Investigation of switching mechanism in HfOx-ReRAM under low power and conventional operation modes

• Published in: Scientific reports Vol. 6; no. 1; p. 39510
• Main Authors: Feng, Wei, Shima, Hisashi, Ohmori, Kenji, Akinaga, Hiroyuki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21-12-2016; Nature Publishing Group
• Subjects: 639/166/987; 639/766/1130/2798; Humanities and Social Sciences; multidisciplinary; Random access memory; Science; Tin; Traps
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep39510

Low-power resistive random access memory (LP-ReRAM) devices have attracted increasing attention owing to their advantages of low operation power. In this study, a vertical-type LP-ReRAM consisting of TiN/Ti/HfO
2
/TiN structure was fabricated. The switching mechanism for LP-ReRAM was elucidated as the conductive filament mechanism for conventional mode, and an interface-type switching mechanism for low power mode was proposed. The analysis of low frequency noise shows that power spectral density (PSD) is approximately proportional to 1/
f
for conventional operation mode. Nevertheless, for low power mode, the PSD of low resistance state (LRS) is proportional to 1/
f
, while that of high resistance state (HRS) is clear proportional to 1/
f
2
. The envelope of multiple Lorentzian spectra of 1/
f
2
characteristics due to different traps reveals the characteristics of 1/
f
. For HRS of low power mode, a limited number of traps results in a characteristic of 1/
f
2
. During the set process, the number of oxygen vacancies increases for LRS. Therefore, the PSD value is proportional to 1/
f
. Owing to the increase in the number of traps when the operation mode changes to conventional mode, the PSD value is proportional to 1/
f
. To the best of our knowledge, this is the first study that reveals the different noise characteristics in the low power operation mode from that in the conventional operation mode.