Phase Change Ge-Rich Ge-Sb-Te/Sb2Te3 Core-Shell Nanowires by Metal Organic Chemical Vapor Deposition.

Arun Kumar,Valentina Mussi,Giuseppe Nicotra,Raffaella Calarco,Raimondo Cecchini,Claudia Wiemer,Mario Scuderi,Sara De Simone,Massimo Longo

doi:10.3390/nano11123358

Arun Kumar, Valentina Mussi + Show 7 more

Open Access

https://doi.org/10.3390/nano11123358

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Journal: Nanomaterials	Publication Date: Dec 10, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: Institute for Microelectronics and Microsystems

Abstract

Ge-rich Ge–Sb–Te compounds are attractive materials for future phase change memories due to their greater crystallization temperature as it provides a wide range of applications. Herein, we report the self-assembled Ge-rich Ge–Sb–Te/Sb2Te3 core-shell nanowires grown by metal-organic chemical vapor deposition. The core Ge-rich Ge–Sb–Te nanowires were self-assembled through the vapor–liquid–solid mechanism, catalyzed by Au nanoparticles on Si (100) and SiO2/Si substrates; conformal overgrowth of the Sb2Te3 shell was subsequently performed at room temperature to realize the core-shell heterostructures. Both Ge-rich Ge–Sb–Te core and Ge-rich Ge–Sb–Te/Sb2Te3 core-shell nanowires were extensively characterized by means of scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, Raman microspectroscopy, and electron energy loss spectroscopy to analyze the surface morphology, crystalline structure, vibrational properties, and elemental composition.

Highlights

We focused on the synthesis of a Ge-rich Ge–Sb–Te/Sb2 Te3 NW based heterostructure, which could meet the industrial specifications from the point of view of the thermal stability of phase change memories (PCM)
We report on the bottom-up, Au catalyzed, metal-organic chemical vapor deposition (MOCVD) growth of Ge-rich Ge–Sb–Te/Sb2 Te3 core-shell NWs
We reported the optimized MOCVD synthesis of crystalline ternary Ge-rich Ge–Sb–Te

Summary

Introduction

Chalcogenide materials have gained the interest of the microelectronic industry because of their fast data-storage speed, high endurance, reduced power consumption, high scalability, and cost effective production for the generation of electronic phase change memories (PCM) [1,2,3]. The PCM data storage mechanism exploits the fast and reversible phase transitions of chalcogenide compounds, driven by electrical pulses, so that a resistivity contrast between the amorphous and crystalline phases is generated, to which digital information can be associated [4]. GST is a typical phase-change compound exhibiting fast phase transitions between the amorphous and crystalline states. Such a structural modification involves the switching between the low and high electrical resistivity states associated with the two phases of the compound [11,12]

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