Impact of hydrostatic pressure on the structure and electrical properties of Ge2Sb2Te5 films for phase change memory applications

Z. Liu, B. Xu, Yi Su
Nanjing University, CN

Keywords: electronics, microsystems

Summary:

Phase-change materials have been extensively studied because of the potential applications in phase-change random access memory (PCRAM), which is a potential candidate of next-generation nonvolatile memory devices in nanoscale. PCRAMs are based on the large electrical contrast between the amorphous phase and the crystalline phase. Ge2Sb2Te5 (GST) is the most promising candidates. It has been reported that the three phases of GST have disparate atomic densities: 0.034 atoms/A3, 0.033 atoms/A3, and 0.031 atoms/A3 for the hexagonal, cubic, and amorphous phases, respectively. As the phase-change material was confined in a closed space, significant mechanical stress will be introduced by repeated phase-change operation. The stress will inevitably affect the electrical properties of the material and the performance of the devices. A combination of experiments and first-principles method calculations has been applied to investigate the influence of the hydrostatic pressure on the electrical properties of GST. The dEg/dP obtained from theoretical calculations and the dPdρln by experimental result are in the same order of magnitude.