Browsing by Author "Wang, Li-Yeh"

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Electroless Deposition of Ru Films Via an Oxidative-Reductive Mechanism
(2011)
Chen, Jing-Yu
;
Hsieh, Yu-Chi
;
Wang, Li-Yeh
;
Wu, Pu-Wei
;
材料科學與工程學系
An electroless Ru plating bath is prepared by mixing Ru precursor (K(2)RuCl(5).xH(2)O), oxidizer (NaClO), stabilizer (NaOH), and reducing agent (NaNO(2)) simultaneously in deionized water at a molar ratio of 1:1:20:10. Instead of conventional direct reduction route, the RuCl(5)(2-) experiences an oxidative-reductive sequence to form metallic Ru on an activated Si substrate. Spectra from ultraviolet-visible and X-ray absorption spectroscopy indicate that the RuCl(5)(2-) is oxidized to form RuO(4) initially, followed by a slight reduction becoming RuO(4)(2-). The RuO(4)(2-) solution is relatively stable and is able to undergo further reduction to render metallic Ru via heterogeneous nucleation and growth. Images from scanning electron microscope demonstrate a solid film of 100 nm with scattered protrusions and cavities after 120 min plating time. Analysis from atomic force microscope determines its surface roughness of 7.8 nm. From X-ray diffraction patterns, the as-deposited film reveals an amorphous structure but turns crystalline after Ar annealing at 400 degrees C for 2 h. Curve-fitting of Ru 3p(3/2) signal from X-ray photoelectron spectroscopy suggests a film composition of 92.49 atom % Ru and 7.51 atom % RuO(2). The electroless Ru plating bath exhibits impressive life time (137 h) and negligible homogeneous precipitation without involving surfactants and unnecessary chemical additives. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3592996] All rights reserved.
Preparation and characterization of ruthenium films via an electroless deposition route
(2010-10-01)
Chen, Jing-Yu
;
Wang, Li-Yeh
;
Wu, Pu-Wei
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A metallic Ru film was prepared by an electroless deposition method, followed by hydrogen reduction treatment. The electroless deposition formulation produced a solid film on a Cu-coated Si substrate at 40 degrees C preactivated by PdCl(2) solution. Chemicals including K(2)RuCl(5)center dot xH(2)O, NaNO(2), NaOH, and NaClO were mixed in a proper ratio that enabled heterogeneous nucleation and film growth. Results from X-ray photoelectron spectroscopy (XPS) on the as-deposited films confirmed the presence of RuO(x) and Ru, while X-ray diffraction (XRD) pattern suggested an amorphous nature. Planar images from a scanning electron microscope revealed a rather smooth surface at thickness less than 250 nm. Above that formation of surface crack and partial detachment from the substrate were observed. After hydrogen reduction at 200 degrees C for 2 h, we obtained a metallic Ru film, as confirmed by XPS and XRD. In addition, the surface roughness was increased due to the formation of pinholes that was caused by the volume contraction associated with RuO(x) reduction to Ru. (C) 2010 Elsevier B.V. All rights reserved.