R&D: Novel Nanocomposite-Superlattices for Low Energy and High Stability Nanoscale Phase-change Memory

Nature Communications has published an article written by Xiangjin Wu, Asir Intisar Khan, Department of Electrical Engineering, Stanford University, Stanford, CA, USA, Hengyuan Lee, Chen-Feng Hsu, Corporate Research, Taiwan Semiconductor Manufacturing Company (TSMC), Hsinchu, Taiwan, Huairuo Zhang, Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, USA, and Theiss Research, Inc., La Jolla, CA, USA, Heshan Yu, Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA, and School of Microelectronics, Tianjin University, Tianjin, China, Neel Roy, Department of Electrical Engineering, Stanford University, Stanford, CA, USA, Albert V. Davydov, Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, USA , Ichiro Takeuchi, Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA, Xinyu Bao, Corporate Research, Taiwan Semiconductor Manufacturing Company (TSMC), San Jose, CA, USA , H.-S. Philip Wong, Department of Electrical Engineering, Stanford University, Stanford, CA, USA , and Eric Pop, Department of Electrical Engineering, Stanford University, Stanford, CA, USA, Department of Materials Science & Engineering, Stanford University, Stanford, CA, USA, and Precourt Institute for Energy, Stanford University, Stanford, CA, USA.

Abstract: “Data-centric applications are pushing the limits of energy-efficiency in today’s computing systems, including those based on phase-change memory (PCM). This technology must achieve low-power and stable operation at nanoscale dimensions to succeed in high-density memory arrays. Here we use a novel combination of phase-change material superlattices and nanocomposites (based on Ge₄Sb₆Te₇), to achieve record-low power density ≈ 5 MW/cm² and ≈ 0.7 V switching voltage (compatible with modern logic processors) in PCM devices with the smallest dimensions to date (≈ 40 nm) for a superlattice technology on a CMOS-compatible substrate. These devices also simultaneously exhibit low resistance drift with 8 resistance states, good endurance (≈ 2 × 10⁸ cycles), and fast switching (≈ 40 ns). The efficient switching is enabled by strong heat confinement within the superlattice materials and the nanoscale device dimensions. The microstructural properties of the Ge₄Sb₆Te₇ nanocomposite and its high crystallization temperature ensure the fast-switching speed and stability in our superlattice PCM devices. These results re-establish PCM technology as one of the frontrunners for energy-efficient data storage and computing.“