Browsing by Author "Xi, P. B."

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Tungsten nanocrystal memory devices improved by supercritical fluid treatment
(2007-12-03)
Chen, C. H.
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Chang, T. C.
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Liao, I. H.
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Xi, P. B.
;
Tsai, C. T.
A supercritical CO(2) (SCCO(2)) fluid technique is proposed to improve electrical characteristics for W nanocrystal nonvolatile memory devices, since the thickness and quality of tunnel oxide are critical issues for the fabrication of nonvolatile memory devices. After SCCO(2) treatments, C-V curves are restored to normal, as well as the leakage current of W nanocrystal memory devices are reduced significantly. It reveals that W nanocrystal memory devices could be formed with shorter oxidation time, moreover, dangling bonds and trapping states initially created within an incomplete oxidized film will be efficiently repaired after SCCO(2) treatment. (c) 2007 American Institute of Physics.
Tungsten oxide/tungsten nanocrystals for nonvolatile memory devices
(2008-01-07)
Chen, C. H.
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Chang, T. C.
;
Liao, I. H.
;
Xi, P. B.
;
Hsieh, Joe
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.