Structural and Electrical Properties of Annealed Ge2Sb2Te5 Films Grown on Flexible Polyimide

The morphological, structural, and electrical properties of as-grown and annealed Ge2Sb2Te5(GST) layers, deposited by RF-sputtering on flexible polyimide, were studied by means of opticalmicroscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy, and electrical characterization.The X-ray diffraction annealing experiments showed the structural transformation of GSTlayers from the as-grown amorphous state into their crystalline cubic and trigonal phases. The onsetof crystallization of the GST films was inferred at about 140°C. The vibrational properties of thecrystalline GST layers were investigated via Raman spectroscopy with mode assignment in agreementwith previous works on GST films grown on rigid substrates. The electrical characterization revealeda good homogeneity of the amorphous and crystalline trigonal GST with an electrical resistancecontrast of 8 X 106.