Tungsten oxide/tungsten nanocrystals for nonvolatile memory devices

摘要

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 ～8.4 nm, while density is ～1.57 ×10~(11) cm~(-2). Moreover, the nonvolatile memory device for WO_3/W nanocrystals exhibits ～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.