Issue 11, 2023

Fabrication of stable multi-level resistance states in a Nb-doped Ge2Sb2Te5 device

Abstract

We report a phase-change memory with controllable multiple-resistance states. Many chemical doping studies have been performed on phase-change materials; however, few have focused on chemical bonding between the doped and host atoms. Phase changes in the doped system exhibited strong bond-length dependences between the doped element X and Te in X–Te polyhedrons. The most stable doped system was when the bond length was similar to that of Ge–Te in Ge2Sb2Te5 (GST). We used Nb doping in GST for a stable multi-level state for phase-change memory applications because of the similar Nb–Te and Ge–Te bond lengths. Nb-doped GST enhanced structural stability and resulted in a continuum of multi-level resistance states with low resistance drift. Ab initio molecular-dynamics simulations were performed to model the local motif in amorphous Nb-doped GST. The phase-change speed in GST was not affected by Nb doping because the dominating octahedral motif was unchanged. Atomic mobility was suppressed, leading to enhanced stability in the amorphous state. Nb-GST thin films thus had significant advantages for multi-level PCM applications.

Graphical abstract: Fabrication of stable multi-level resistance states in a Nb-doped Ge2Sb2Te5 device

Article information

Article type
Paper
Submitted
19 Jan 2023
Accepted
25 Feb 2023
First published
27 Feb 2023

J. Mater. Chem. C, 2023,11, 3770-3777

Fabrication of stable multi-level resistance states in a Nb-doped Ge2Sb2Te5 device

L. Zheng, Z. Song, W. Song, X. Zhu and S. Song, J. Mater. Chem. C, 2023, 11, 3770 DOI: 10.1039/D3TC00233K

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