Tungsten oxide/tungsten nanocrystals for nonvolatile memory devices

Abstract

In this work, the fabrication of WO(3)/W nanocrystals for nonvolatile memory devices has been achieved via rapid thermal oxidation of tungsten silicide. Amorphous Si and WSi(x) (x=2.7) layers were deposited onto the tunneling oxide and sequentially oxidized to form well-shaped WO(3)/W nanocrystals. The mean size of WO(3)/W nanocrystals is similar to 8.4 nm, while density is similar to 1.57x10(11) cm(-2). Moreover, the nonvolatile memory device for WO(3)/W nanocrystals exhibits similar to 0.53 V threshold voltage shift under 1 V/(-5 V) operation. The sample without capping a-Si layer was also fabricated for comparison. By material analyses, reasonable formation mechanisms are proposed in this letter. (C) 2008 American Institute of Physics.