Nanoscale mechanically induced structural and electrical changes in Ge2Sb2Te5 films

Abstract

We demonstrate that the microstructure and electrical properties of Ge2Sb2Te5 films can be changed by a nanoscale mechanical process. Nanoscratching is used to define modified areas onto an as-deposited crystalline Ge2Sb2Te5 film. Scanning tunneling microscopy measurements show that the modified areas have a very low electrical conductivity. Micro-Raman measurements indicate that the mechanically induced microstructural changes are consistent with a phase transformation from crystalline to amorphous, which can be reversed by laser irradiation.

Crystallization process of in situ annealed Ge2Sb2Te5 films

“…Currently, Ge 2 Sb 2 Te 5 (GST) films are the best chalcogenide material for PCM and have received sustained attention [7][8][9][10][11]. In PCM, the data writing/erasing process is achieved by using the heat generated by a laser pulse or an electric pulse to induce phase transitions between an amorphous phase and a polycrystalline phase in the GST films.…”