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Area-Type Electronic Bipolar Switching Al/TiO1.7/TiO2/Al Memory with Linear Potentiation and Depression Characteristics
journal contribution
posted on 2021-08-11, 12:36 authored by Yu Yan, Jia Cheng Li, Yu Ting Chen, Xiang Yu Wang, Gang Ri Cai, Hyeon Woo Park, Ji Hun Kim, Jin Shi Zhao, Cheol Seong HwangIn electronic bipolar resistive switching (eBRS), the electron
trapping and detrapping at the defect sites within the switching layer,
such as the highly defective TiO1.7 in this study, constitute
the switching mechanism. It is an appealing candidate solution to
the nonuniformity issue of resistive switching memory. However, TiO1.7-based eBRS has suffered from a lack of endurance and retention.
In this study, a 7 nm-thick stoichiometric TiO2 layer is
interposed between an Al bottom electrode and a 50 nm-thick TiO1.7 layer, which is in contact with an Al top electrode. Despite
the minimal structural modification, improvements in the electrical
performance were substantial. The off-to-on state resistance ratio
of 20 and the resistance values could be retained up to 30 000
direct current sweep cycles and 106 alternating current
pulse switching cycles. Data retention also significantly improves.
Moreover, the device is electroforming-free and shows fully area-type
switching characteristics. Such notable improvements are attributed
to the favorable energy band structure of the Al/TiO1.7/TiO2/Al structure. The device shows almost linear potentiation
and depression characteristics after the repeated pulse voltage applications,
which significantly improves the accuracy of the neural network, the
synapses of which are composed of the Al/TiO1.7/TiO2/Al memory cells.