title: Resistance switching mode transformation in SrRuO3/Cr-doped SrZrO3/Pt frameworks via a thermally activated Ti out-diffusion process.
abstract: This work reports on a mechanism for irreversible resistive switching (RS) transformation from bipolar to unipolar RS behavior in SrRuO3 (SRO)/Cr-doped SrZrO3 (SZO:Cr)/Pt capacitor structures prepared on a Ti/SiO2/Si substrate. Counter-clockwise bipolar RS memory current-voltage (I-V) characteristics are observed within the RS voltage window of -2.5 to +1.9 V, with good endurance and retention properties. As the bias voltage increases further beyond 4 V under a forward bias, a forming process occurs resulting in irreversible RS mode transformation from bipolar to unipolar mode. This switching mode transformation is a direct consequence of thermally activated Ti out-diffusion from a Ti adhesion layer. Transition metal Ti effectively out-diffuses through the loose Pt electrode layer at high substrate temperatures, leading to the unintended formation of a thin titanium oxide (TiO(x) where x < 2) layer between the Pt electrode and the SZO:Cr layer as well as additional Ti atoms in the SZO:Cr layer. Cross-sectional scanning electron microscopy, transmission electron microscopy and Auger electron spectroscopy depth-profile measurements provided apparent evidence of the Ti out-diffusion phenomenon. We propose that the out-diffusion-induced additional Ti atoms in the SZO:Cr layer contributes to the creation of the metallic filamentary channels.
authors.affiliation: Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea.
authors.forename: Yongcheol
authors.initials: Y
authors.lastname: Jo
authors.affiliation: 1] Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea [2] R&D Division, Flash Integration Technology Team, SK-Hynix, 2091 Gyeongchung daero Bubal-eub, Icheon-si Gyeonggi-do, Korea.
authors.forename: Kyooho
authors.initials: K
authors.lastname: Jung
authors.affiliation: Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea.
authors.forename: Jongmin
authors.initials: J
authors.lastname: Kim
authors.affiliation: Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea.
authors.forename: Hyeonseok
authors.initials: H
authors.lastname: Woo
authors.affiliation: Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea.
authors.forename: Jaeseok
authors.initials: J
authors.lastname: Han
authors.affiliation: Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea.
authors.forename: Hyungsang
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Physics, Hanyang University, Seoul, Korea.
authors.forename: Jinpyo
authors.initials: J
authors.lastname: Hong
authors.affiliation: Future Convergence Research Division, Interface Control Research Center, Korea Institute Science &Technology (KIST), Seoul 136-791, Republic of Korea.
authors.forename: Jeon-Kook
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Division of Physics and Semiconductor Science, Dongguk University, Seoul 100-715, Korea.
authors.forename: Hyunsik
authors.initials: H
authors.lastname: Im