R&D: Ultralow–Switching Current Density Multilevel PCM on Flexible Substrate

Science has published an article written by Asir Intisar Khan, Alwin Daus, Raisul Islam, Kathryn M. Neilson, Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA, Hye Ryoung Lee, Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA, and Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 USA, H.-S. Philip Wong, Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA, Eric Pop, Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA, Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 USA, and Precourt Institute for Energy, Stanford University, Stanford, CA 94305, USA.

Abstract: “Phase-change memory (PCM) is a promising candidate for data storage in flexible electronics, but its high switching current and power are often drawbacks. In this study, we demonstrate a switching current density of ~0.1 mega-ampere per square centimeter in flexible superlattice PCM, a value that is one to two orders of magnitude lower than in conventional PCM on flexible or silicon substrates. This reduced switching current density is enabled by heat confinement in the superlattice material, assisted by current confinement in a pore-type device and the thermally insulating flexible substrate. Our devices also show multilevel operation with low resistance drift. The low switching current and good resistance on/off ratio are retained before, during, and after repeated bending and cycling. These results pave the way to low-power memory for flexible electronics and also provide key insights for PCM optimization on conventional silicon substrates.“