CoSi 2 -coated Si nanocrystal memory

Abstract

CoSi 2 -coated Si nanocrystals were fabricated as the floating gates for nonvolatile memory applications to improve the Si nanocrystal memory performance in terms of programming/erasing efficiency and retention time. Discrete CoSi2-coated Si nanocrystals were formed by silicidation of Si nanocrystals on SiO2 and subsequent selective etching of unreacted metal cobalt over silicide. Metal-oxide-semiconductor field-effect transistor memories with CoSi2-coated Si nanocrystals and reference Si nanocrystals as floating gates were fabricated and characterized. Longer retention, larger charging capability and faster programming/erasing were observed in CoSi2-coated Si nanocrystal memory compared with Si nanocrystal memory. CoSi2 Fermi-level pinning of defect levels plays important role in the device performance enhancement.