Title: Superior bipolar resistive switching characteristics of Cu-TiO2 based RRAM cells

Authors: Yu-Chih Huang; Huan-Min Lin; Huang-Chung Cheng

Addresses: Department of Electronics Engineering, National Chiao Tung University, Room 309b, Engineering Building 4, 1001 University Road, Hsinchu City 30010, Taiwan ' Department of Electronics Engineering, National Chiao Tung University, Room 309b, Engineering Building 4, 1001 University Road, Hsinchu City 30010, Taiwan ' Department of Electronics Engineering, National Chiao Tung University, Room 309b, Engineering Building 4, 1001 University Road, Hsinchu City 30010, Taiwan

Abstract: Resistive random access memory (RRAM) cells with Cu-doped TiO2 film between two Pt inert electrodes are produced in this work, and these achieve a lower required programming voltage of −0.7 V and higher endurance of about 1000 cycles at the programming/erasing voltage of −5 V/+3 V for the pulse width of 1 μs, compared with the conventional Pt/TiO2/Cu ones. It is conjectured that the distribution of Cu sources in the Cu-doped TiO2 (TiO2 : Cu) resistive switching film facilitates the formation of sharp and narrow conductive filaments, attributed to the Cu sources near the negative biased Pt electrode were oxidised more easily to become the Cu cations than those in other regions. The proposed Pt/TiO2 : Cu/Pt sample can thus achieve a lower DC programming voltage than the conventional one. Moreover, it is conjectured that the better endurance of the Pt/TiO2 : Cu/Pt sample is due to the lower amount of residual Cu atoms in the TiO2 layer from the ruptured filaments during the erasing process. This is because the increase in the amount of Cu atoms is limited by the inert Pt electrode when there are uniformly distributed Cu sources and there is no Cu electrode.

Keywords: RRAM; resistive RAM; random access memory; CBRAM; conductive-bridging RAM; PMC; programmable metallisation cell; metal oxide; dielectric; nanoelectronics; nanotechnology; bipolar resistive switching; copper doping; titanium dioxide; titania.

DOI: 10.1504/IJNT.2014.059819

International Journal of Nanotechnology, 2014 Vol.11 No.1/2/3/4, pp.156 - 166

Available online: 13 Mar 2014 *

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