Formation of Ge2Sb2Te5-TiOx Nanostructures for Phase Change Random Access Memory Applications

Amorphous Ge2Sb2Te5 clusters with a size of 20 nm, self-enclosed by a thin layer of TiOx, were obtained by cosputtering Ge2Sb2Te5 and TiO2 targets at room temperature with the aim of reducing the reset current for phase change random access memory applications. Eutectic decomposition during the deposition caused a phase separation of Ge2Sb2Te5 and TiOx. The temperature-dependent resistance change results showed that the activation energy for crystallization increased from 2.44 +/- 0.76 to 3.84 +/- 1.43 eV in the Ge2Sb2Te5 film. The set resistance can be tuned within an acceptable range, and the reliability of this microstructure during repetitive laser melt-quenching cycles was tested. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3264734] All rights reserved.