Multi-level optical memory based in Ge1Sb2Te4

Abstract

The aim of this work was to develop an active material for optical memory phase change that allows multilevel record. We measure the reflectance of Ge1Sb2Te4 films doped with oxygen with a Static Meter of Reflectivity by laser SMRL, which was built specially for this application. Experimental reflectance results shown that the nucleation time tnucl (minimum duration of the laser pulse to start the laser induced crystallization) and the crystallization time tcrys (time it takes to crystallize the material) depend on the concentration of oxygen. X ray diffraction showed that films with high percentage oxygen concentration (10- 18 %) have a phase segregation of Sb2Te3. This phase segregation in films containing more than 10% oxygen gives, as a result, an increase in nucleation times and in laser-induced crystallization times, allowing multilevel recording.