The influence of copper top electrodes on the resistive switching effect in TiO2 thin films studied by conductive atomic force microscopy

Titanium dioxide thin films (30 nm) are deposited on platinized substrates by atomic layer deposition and locally studied by conductive atomic force microscopy showing repetitive bipolar resistive switching. Experiments using macroscopic copper top electrodes, which are electroformed, bipolar switched, and removed again from the TiO2–Pt stack, prove the formation of local conductive filaments with bipolar switching properties. The localized filaments can be switched repetitively with a resistance ratio of 30. Our findings underline that Cu diffusion and the formation of filaments are the major mechanism for the resistive switching in Cu/TiO2/Pt cells.

[1]  M. Kozicki,et al.  Nanoscale memory elements based on solid-state electrolytes , 2005, IEEE Transactions on Nanotechnology.

[2]  Rainer Waser,et al.  Impedance spectroscopy of TiO2 thin films showing resistive switching , 2006 .

[3]  Byung Joon Choi,et al.  Resistive switching mechanism of TiO2 thin films grown by atomic-layer deposition , 2005 .

[4]  S. O. Park,et al.  Electrical observations of filamentary conductions for the resistive memory switching in NiO films , 2006 .

[5]  R. Waser,et al.  Piezoresponse in the light of surface adsorbates: Relevance of defined surface conditions for perovskite materials , 2004 .

[6]  T. Sakamoto,et al.  A nonvolatile programmable solid-electrolyte nanometer switch , 2004, IEEE Journal of Solid-State Circuits.

[7]  Rainer Waser,et al.  Influence of adsorbates on the piezoresponse of KNbO3 , 2006 .

[8]  K. Terabe,et al.  Quantized conductance atomic switch , 2005, Nature.

[9]  C. Gerber,et al.  Reproducible switching effect in thin oxide films for memory applications , 2000 .

[10]  M. Kozicki,et al.  Bipolar and Unipolar Resistive Switching in Cu-Doped $ \hbox{SiO}_{2}$ , 2007, IEEE Transactions on Electron Devices.

[11]  M. Kozicki,et al.  A Low-Power Nonvolatile Switching Element Based on Copper-Tungsten Oxide Solid Electrolyte , 2006, IEEE Transactions on Nanotechnology.

[12]  R. Waser,et al.  Nanoionics-based resistive switching memories. , 2007, Nature materials.

[13]  D. Bremaud,et al.  Electrical current distribution across a metal–insulator–metal structure during bistable switching , 2001, cond-mat/0104452.

[14]  R. Waser,et al.  Switching the electrical resistance of individual dislocations in single-crystalline SrTiO3 , 2006, Nature materials.

[15]  M. Kozicki,et al.  Low current resistive switching in Cu–SiO2 cells , 2008 .

[16]  Rainer Waser,et al.  Nanoscale resistive switching in SrTiO3 thin films , 2007 .