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Three Resistance States Achieved by Nanocrystalline Decomposition in Ge‐Ga‐Sb Compound for Multilevel Phase Change Memory
Author(s) -
Zhang Liwei,
Mai Xianliang,
Gu Rongchuan,
Liu Long,
Xiong Changying,
Yang Zhe,
Tong Hao,
Cheng Xiaomin,
Xu Ming,
Zhou Peng,
Miao Xiangshui
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202100164
Subject(s) - materials science , nanocrystalline material , amorphous solid , non volatile memory , optoelectronics , phase change memory , nanotechnology , crystallography , layer (electronics) , chemistry
Phase‐change memory (PCM), using the fast and reversible transition between crystal and glass to store binary data, is a promising candidate for next‐generation information storage and computing technologies. Recording more than one bit of information on each memory cell, known as multilevel cell (MLC) technology, can greatly increase the data density of PCMs. In this paper, the MLC capability in a phase change material Ge‐Ga‐Sb (GGS) is explored. Using the “SET” operation with increasing voltage amplitudes on this PCM cell in a 250 nm pillar structure device, three resistance levels are achieved and can be stabilized within large operating voltage windows, allowing large tolerance of SET voltage variation which may lead to the overlap of the neighboring resistance levels. It is discovered that the additional resistance level other than “0” and “1” is enabled by compositional phase separation in the nanocrystalline GGS, as revealed via atom probe tomography and electronic microscopy. The device also shows small resistance drift (ν = 0.025) in amorphous state, about four times lower than prototypical Ge‐Sb‐Te‐based PCMs, stabilizing it against time variation. Meanwhile, high thermal stability ( T c ≈ 300 °C) in GGS‐based device can also facilitate the practical applications in some extreme conditions.