Improvement in thermal stability and crystallization mechanism of Sm doped Ge2Sb2Te5 thin films for phase change memory applications

The thin films of (Ge2Sb2Te5)(100-x)Sm-x (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2) (Sm-GST) phase change material have been investigated employing X-ray photoelectron spectroscopy (XPS) to examine the nature of chemical bonding in as-deposited thin films of Sm-GST. The composition of as-deposited thin films of Sm-GST has been also analyzed from the peak area ratios of XPS core-level spectra and the morphology of the thin film has been studied using field emission scanning electron microscopy (FESEM). The powder samples obtained from the as-deposited thin films have been utilized for the non-isothermal differential scanning calorimetry (DSC) measurements at the constant heating rate of 10 K/min. The values of glass transition temperature (T-g), onset crystallization (T-c), peak crystallization temperature (T-p) and melting temperature (T-m) obtained from DSC curves of Sm-GST thin films have been used for the evaluation of thermal stability parameters. The activation energy for crystallization (E-c) and avrami exponent (n) for fcc and hexagonal phase of Sm-GST thin films have been evaluated using Henderson's method and Matusita's method. The impact of Sm doping on the thermal stability, glass-forming ability and crystallization activation energy of as-deposited thin films have been examined and its possible influence on the memory device performance has been correlated. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Thin films of (Ge2Sb2Te5)(100-x)Sm-x (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2) (Sm-GST) phase change material were studied to examine the chemical bonding, composition, morphology, thermal stability parameters, and crystallization activation energy. Results showed that Sm doping affects the thermal stability, glass-forming ability, and crystallization behavior of the thin films, potentially impacting the performance of memory devices.