"Stickier"-Surface Sb2Te3 Templates Enable Fast Memory Switching of Phase Change Material GeSb2Te4 with Growth-Dominated Crystallization

Jinlong Feng; Andriy Lotnyk; Hagen Bryja; Xiaojie Wang; Meng Xu; Qi Lin; Xiaomin Cheng; Ming Xu; Hao Tong; Xiangshui Miao

doi:10.1021/acsami.0c07973

"Stickier"-Surface Sb₂Te₃ Templates Enable Fast Memory Switching of Phase Change Material GeSb₂Te₄ with Growth-Dominated Crystallization

ACS Appl Mater Interfaces. 2020 Jul 22;12(29):33397-33407. doi: 10.1021/acsami.0c07973. Epub 2020 Jul 13.

Authors

Jinlong Feng^{1

2

3}, Andriy Lotnyk^{2

4}, Hagen Bryja², Xiaojie Wang^{1

3}, Meng Xu^{1

3}, Qi Lin^{1

3}, Xiaomin Cheng^{1

3}, Ming Xu^{1

3}, Hao Tong^{1

3}, Xiangshui Miao^{1

3}

Affiliations

¹ Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
² Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, Leipzig 04318, Germany.
³ Hubei Key Laboratory of Advanced Memories, Huazhong University of Science and Technology, Wuhan 430074, China.
⁴ Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China.

PMID: 32597166
DOI: 10.1021/acsami.0c07973

Abstract

Ge-Sb-Te (GST)-based phase-change memory (PCM) excels in the switching performance but remains insufficient of the operating speed to replace cache memory (the fastest memory in a computer). In this work, a novel approach using Sb₂Te₃ templates is proposed to boost the crystallization speed of GST by five times faster. This is because such a GST/Sb₂Te₃ heterostructure changes the crystallizing mode of GST from the nucleation-dominated to the faster growth-dominated one, as confirmed by high-resolution transmission electron microscopy, which captures the interface-induced epitaxial growth of GST on Sb₂Te₃ templates in devices. Ab initio molecular dynamic simulations reveal that Sb₂Te₃ templates can render GST sublayers faster crystallization speed because Sb₂Te₃'s "sticky" surface contains lots of unpaired electrons that may attract Ge atoms with less antibonding interactions. Our work not only proposes a template-assisted PCM with fast speed but also uncovers the hidden mechanism of Sb₂Te₃'s sticky surface, which can be used for future material selection.

Keywords: GeSb2Te4; Sb2Te3 template; fast crystallization; phase-change memory; surface state.