Fabrication and Evaluation of Nanopillar-Shaped Phase-Change Memory Devices

Abstract

In this study, nanopillar-shaped phase-change memory devices of various sizes were simply fabricated by nanosphere lithography, and their electrical characteristics were evaluated by conductive atomic force microscopy (AFM). As nanosphere materials, 180-nm diameter polystyrene balls were used for a size-controllable mask, silica balls with a diameter of 200 nm for a high etching-resistance mask, and sub-50 nm Ag nanoparticles were used for sub-50-nm-scale fabrication. Using the polystyrene balls, silica balls, and Ag nanoparticles, nanopillar-shaped phase-change memory devices with various diameters, heights as large as 1 mu m, and sizes as small as less than 50 nm were successfully fabricated. The electrical properties of the nanopillar-shaped Ge2Sb2Te5 devices were evaluated by conductive AFM with an electrical measurement system. (C) 2011 The Japan Society of Applied Physics