Nano-polycrystalline Ag-doped ZnO layer for steep-slope threshold switching selectors
Akshay Sahota,
Harrison Sejoon Kim,
Jaidah Mohan,
Dan N. Le,
Yong Chan Jung,
Si Joon Kim,
Jang-Sik Lee,
Jinho Ahn,
Heber Hernandez-Arriaga,
Jiyoung Kim
Affiliations
Akshay Sahota
Department of Electrical Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Harrison Sejoon Kim
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Jaidah Mohan
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Dan N. Le
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Yong Chan Jung
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Si Joon Kim
Department of Electrical and Electronics Engineering, Kangwon National University, 1 Gangwondaehakgil, Chuncheon, Gangwon-do 24341, Republic of Korea
Jang-Sik Lee
Department of Material Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Pohang 790-784, Republic of Korea
Jinho Ahn
Division of Materials Science and Engineering, Hanyang University, 222 Wangshimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
Heber Hernandez-Arriaga
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Jiyoung Kim
Department of Electrical Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
In this work, a nano-polycrystalline Ag-doped ZnO-based threshold switching (TS) selector via a facile co-sputtering technique is investigated without using an Ag active metal layer. The effects of the Ag concentration with respect to OFF-state leakage current (Ioff) were studied, and the results demonstrate that by regulating the Ag doping concentration in the switching layer (SL), an electroforming-free switching with an Ion/Ioff ratio of ∼108 could be achieved, having an extremely low Ioff value of ∼10−13 A. Furthermore, cycling endurance can also be improved as the formation of a laterally thick and stable filament does not happen promptly with consequent measurements when there is a limited amount of Ag in the SL. The selector device performance enhancement is attributed to the doping-based polycrystalline structure that facilitates enhanced control on filament formation due to the restricted availability and anisotropic diffusion of Ag ions in the polycrystalline ZnO SL, thereby trimming down the overall stochasticity during metallic filament growth. The present study demonstrates that a doping-based polycrystalline SL structure can be implemented in a selector device to augment TS characteristics, i.e., device variances and cycling endurance for adoption in ultra-high density memory applications.
