Effects of postdeposition annealing on cobalt nanodots embedded in silica for nonvolatile memory application

Yanli Pei, Toshiya Kojima, Tatsuro Hiraki, Takafumi Fukushima, Tetsu Tanaka, Mitsumasa Koyanagi

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1 Citation (Scopus)

Abstract

We studied the effects of postdeposition annealing (PDA) on the films of cobalt nanodots (Co-NDs) dispersed in silica formed by self-assembled nanodot deposition (SAND). High-resolution transmission electron microscopy (HRTEM) analysis showed that the as-grown Co-NDs have a high density of 8 ×10 12/cm2 and a small size of ̃1:5 nm. After PDA at 800°C, a monolayer of Co-NDs is produced by agglomeration. Under this PDA condition, the dot size and density are easily controlled by adjusting the thickness of the as-grown Co-ND film. In contrast, a high-temperature PDA of 900°C induces the diffusion of cobalt into the silicon substrate and leads to the failure of memory effect. When the PDA temperature is between 600 and 800°C, a large counterclockwise hysteresis memory window is obtained. Furthermore, in this region, the charge retention is enhanced by increasing the PDA temperature, which presumably contributes to the release of oxygen from oxidized cobalt.

Original languageEnglish
Pages (from-to)665031-665034
Number of pages4
JournalJapanese journal of applied physics
Volume49
Issue number6 PART 1
DOIs
Publication statusPublished - 2010 Jun 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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