Journal of Materiomics

Journal of Materiomics

Volume 8, Issue 2, March 2022, Pages 382-391
Journal of Materiomics

Research paper
Reliable Ge2Sb2Te5 based phase-change electronic synapses using carbon doping and programmed pulses

https://doi.org/10.1016/j.jmat.2021.08.004Get rights and content
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open access

Highlights

  • The concept of integrating material engineering and pulse programming was proposed to obtain PCRAM electronic synapses.

  • Programmed non-linear pulses effectively improve the conductance distribution thus obtaining reliable synaptic simulation.

  • A series of pulse schemes used for spike-timing dependent plasticity exhibit reliable and flexible data collection.

  • All results potentially promote the implementation of PCRAM hardware neuro-inspired computing.

Abstract

Hardware electronic synapse and neuro-inspired computing system based on phase change random access memory (PCRAM) have attracted an extensive investigation. However, due to the intrinsic asymmetric reversible phase transition, the defective weight update of PCRAM synapses in aspects of tuning range, linearity and continuity has long required a system-level complexity of circuits and algorithms. The cell-level improvements to a great extent may slim the system thus achieving efficient computing. We report in this work the great enhancement of Ge2Sb2Te5 (GST) based PCRAM synapses by combining materials engineering and pulse programming. It is found that carbon doping in GST retards the rate of phase changing thus increasing the controllability of the conductance, while non-linear programmable pulse excitations can eventually lead to a reliable synaptic potentiation and depression. A set of improved programmable pulse schemes for spike-timing dependent plasticity was then demonstrated, suggesting its potential superiority in flexible programming and reliable data collection. Our methods and results are of great significance for implementing PCRAM electronic synapses and high-performance neuro-inspired computing.

Keywords

Programmable synapse
Synaptic simulation
PCRAM
C-doped Ge2Sb2Te5
Electronic synapse

Cited by (0)

Qiang Wang received his BS degree in North University of China in 2015 and obtained Master's degree in Central South University, China, in 2018. He is studying for Ph.D degree in the School of Electronic Science and Engineering, Xi'an Jiaotong University. His current research interest is non-volatile memories and its application in neuro-inspired computing.

Dr. Gang Niu was born in Xi'an Shaaxi China in 1982. He received the B.S. in and M.S. degrees in Electronic Science and Engineering Department from Xi'an Jiaotong University in 2004 and 2007, respectively. He obtained the Ph.D. degree in School of Electric Electronic and Automation from Ecole Centrale de Lyon France in 2010.

From 2010 to 2011, he was a post-doctoral researcher at Insitut des Nanotechnologie de Lyon in CNRS France. From 2011 to 2013, he worked at Leibniz Institute for high performance microelectronics (IHP) in Frankfurt (Oder) Germany as a post-doctoral researcher with the support from Alexander von Humboldt foundation. From 2013 to 2015, he worked as a research scientist and project leader at IHP. Since 2015, he has been a Research Professor at the School of Electronic Science and Engineering in Xi'an Jiaotong University. He is the author of one book chapter, more than 80 journal papers. His research interests consist in “More than Moore” materials and devices, including ferroelectric films, monolithic integration of single crystalline oxides with silicon, heteroepitaxy of Ge and III-V compounds with low defect density and non-volatile memories. He is an editorial board member of the IOP journal Nano Express, and holds six patents.

Dr. Niu was a recipient of Alexander von Humboldt fellowship in 2012 and Germany DFG Mercator fellowship in 2019.

Dr. Wei Ren is the chair professor in the School of Electronic Science and Engineering, Xi'an Jiaotong University; the director of the Institute of Ferro Materials and Integrated Devices; and the executive director of the International Center for Dielectric Research, Xi'an Jiaotong University. Dr. Ren received B.S. and Ph.D. degrees from Xi'an Jiaotong University in 1984 and 1992, respectively. He joined Xi'an Jiaotong University in 1987 and was promoted to professorship in 1997. He has held visiting appointments at the Heinrich Hertz Institute in Berlin, Germany (1992–1993), the Materials Research Laboratory of The Pennsylvania State University, University Park, PA (1998–1999), and Department of Physics of the Royal Military College of Canada (1999–2004). Dr. Ren has published more than 290 papers and held 30 Chinese and U.S. patents. His current research interests include piezoelectric and ferroelectric materials for sensor and transducer applications.

Dr. Sannian Song received a Ph.D. degree from the Functional Materials Research Laboratory, Tongji University, Shanghai, China, in 2008. He is now a professor of the State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai, China. Prof. Song has published more than 160 papers and held 40 patents. He has won 2020 First Prize of Shanghai Natural Science Award. His research interests include phase change materials and integrated processes.

Peer review under responsibility of The Chinese Ceramic Society.