Metal - Insulator Transition Driven by Vacancy Ordering in GeSbTe Phase Change Materials

Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystall...

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Published in:Scientific reports 2016-04, Vol.6 (1), p.23843-23843, Article 23843
Main Authors: Bragaglia, Valeria, Arciprete, Fabrizio, Zhang, Wei, Mio, Antonio Massimiliano, Zallo, Eugenio, Perumal, Karthick, Giussani, Alessandro, Cecchi, Stefano, Boschker, Jos Emiel, Riechert, Henning, Privitera, Stefania, Rimini, Emanuele, Mazzarello, Riccardo, Calarco, Raffaella
Format: Article
Language:English
Subjects:
639/301/1005/1008
639/766/119/544
Alloys
Fabrication
Humanities and Social Sciences
multidisciplinary
Optical properties
Random access memory
Science
Thermal energy
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Summary:Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows.
ISSN:2045-2322
2045-2322
DOI:10.1038/srep23843