R&D: Thermal Characterization of Ge-rich GST Thin Films for Phase Change Memories by Raman Thermometry

Journal of Applied Physics has published an article written by Akash Patil, Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, Junia, UMR 8520 – IEMN – Institut d’Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France, and STMicroelectronics, 850 rue jean Monnet 38920 Crolles, France, Yannick Le-Friec, STMicroelectronics, 850 rue jean Monnet 38920 Crolles, France, Pascal Roussel, Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181 – UCCS – Unité de Catalyse et de Chimie du Solide, F-59000 Lille, , France, Yves Deblock, Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, Junia, UMR 8520 – IEMN – Institut d’Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France, Simon Jeannot; STMicroelectronics, 850 rue jean Monnet 38920 Crolles, France, Philippe Boivin, STMicroelectronics, 190 avenue Coq, 13106 Rousset, France, Emmanuel Dubois, Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, Junia, UMR 8520 – IEMN – Institut d’Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France, and Jean-François Robillard, Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, Junia, UMR 8520 – IEMN – Institut d’Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France.

Abstract: “Doped GeSbTe (GST)-based phase change materials are of growing interest due to their ability to enable high-temperature data retention for embedded memory applications. This functionality is achieved through Ge enrichment and addition of dopants such as N and C in stoichiometries such as GST-225, which improve the crystallization temperature and thermal phase stability. In this study, we examine the effect of these dopants on thermal conductivity using Raman thermometry. We report the temperature-dependent thermal conductivity of the amorphous and crystalline phases of Ge-rich GeSbTe (GGST) and Ge-rich GeSbTe N-doped (GGSTN) thin films. The results reveal a surprising temperature dependence of the thermal conductivity of the crystalline phase of GGST and GGSTN, a phenomenon not typically observed for GST-based materials. Additionally, enrichment of Ge and subsequent N-doping result in reduced thermal conductivity, which can benefit the power consumption of phase change memories. From a characterization perspective, Raman thermometry has been developed as a technique for simultaneous structural and thermal characterization of GST-based materials.“