MRS Meetings and Events


EQ11.03.04 2022 MRS Spring Meeting

Monolithic Fabrication of 1S-1R Crossbar Array Using Single GexTe1-x Material by Controlling Composition Between Memory and Threshold Switching for Neuromorphic Application

When and Where

May 10, 2022
9:30am - 9:45am

Hawai'i Convention Center, Level 3, 318A



Sang-Heon Park1,Jihye Lee1,Deok-Jin Jeon1,Jong-Souk Yeo1

Yonsei University1


Sang-Heon Park1,Jihye Lee1,Deok-Jin Jeon1,Jong-Souk Yeo1

Yonsei University1
Bioinspired neuromorphic system is an emerging technology that could revolutionize the present computer architecture. Chalcogenide materials show unique material system with properties for memory and switching devices, thus having a potential to be a crucial element for a reliable neuromorphic computing. To mimic synaptic functions with achieving the highest integration density, one-selector one-resistor (1S-1R) crossbar arrays are becoming next generation memory technology. 1S1R crossbar arrays using non-volatile memory devices and volatile selector devices are capable of desired behavior such as efficient spike-event due to its advantages of low power consumption, large endurance, and great switching characteristics. However, the complexity of the lithographic process for multi-functional layers and the poor stability due to the integration of heterogeneous thin film materials in the 1S1R structure remain challenging to develop technology further.<br/>At present, the chalcogenide materials are attracting research interest for their extensive applications ranging from phase-change materials in nonvolatile memories to volatile threshold switching materials in selector devices or optical, thermoelectric devices. Among these materials, some chalcogenide materials show intriguing properties with the conduction characteristic, which has led to the applications for nonvolatile memory and selector devices. While some of them allow rapid and reversible switching between the amorphous and crystalline state for phase change memory (PCM) application, others exhibit an uncommon conductive behavior under high electric field, called the Ovonic threshold switching (OTS) effect.<br/>In this study, we demonstrate that memory switching and threshold switching can be modulated in a single Ge<sub>x</sub>Te<sub>1-x</sub> material system by controlling the atomic ratio of Ge-Te system. In the memory switching mode both low resistive state (LRS) and high resistive state (HRS) can be maintained after removing the external voltage, while the LRS in the threshold switching mode will return to the HRS once the applied voltage becomes smaller than a critical value. With Te deficient Ge-Te system close to the atomic ratio of 1:1, the device based on this material shows the characteristics of memory switching with high switching speed (&lt;10 ns) and superior endurance (&gt;10<sup>8</sup> cycle). When the Ge-Te material system is Te rich with the atomic ratio close to 1:6, it exhibits threshold switching characteristics as an excellent bi-directional selector with great selectivity (&gt;10<sup>5</sup> ON/OFF ratio) and rapid switching speed (&lt;10 ns), suitable for high-density memory application. Monolithic fabrication of 1S1R structure is demonstrated using our GeTe memory and GeTe<sub>6 </sub>selector with good selectivity (&gt;10<sup>2</sup> ON/OFF ratio) and enough voltage margin. This work can significantly reduce the complexity in the fabrication of stackable devices and improve the understanding of the switching mechanisms in chalcogenide materials, thus opening up wider applications from memory to selector devices for neuromorphic computing.<br/>This research was supported by Korea Semiconductor Research Consortium (KSRC) through a project for developing source technologies for future semiconductor devices and also supported by Samsung Electronics Co. Ltd. (Project number IO2102021-08356-01)


interatomic arrangements

Symposium Organizers

Yoeri van de Burgt, Technische Universiteit Eindhoven
Yiyang Li, University of Michigan
Francesca Santoro, Forschungszentrum Jülich/RWTH Aachen University
Ilia Valov, Research Center Juelich

Symposium Support

Nextron Corporation

Publishing Alliance

MRS publishes with Springer Nature