The Phase Change Effect of Oxygen-Incorporation in GeSbTe Films

Abstract

Reflectivity changes in oxygen-incorporated Ge2Sb2Te5 (GST) films were investigated via a laser-induced crystallization process. The crystallization process showed that the phase change speed and the laser power required for crystallization become faster and larger in GST films with a characteristic quantity of oxygen. We confirmed that a dominant grain growth mode during the laser crystallization is a major determinant for the speed of phase change in GST films with a characteristic quantity of oxygen. JMA results and changes in surface morphology indicate that the origin of the growth mode change is due to an increase in the number of initial nucleation sites produced in the oxygen-incorporated GST films. After the re-amorphization process, oxygen-incorpo-rated GST films show more rapid and more stable phase change properties than that of GST films. VC 2011 The Electrochemical Society. [DOI: 10.1149/1.3556609] All rights reserved. Manuscript submitted December 10, 2010; revised manuscript received January 19, 2011. Published March 8, 2011. GeSbTe-based materials, especially Ge2Sb2Te5 (GST), which is located on the tie-line in the ternary diagram of the GeTe-Sb2Te3 system, have been the subject of extensive studies. GST has many potential applications such as in optical storage media and phase change random access memory devices (PRAM).1–3 Even though GST has many potential uses it also has some disadvantages, which