Browsing by Author "Tsao, Jung-Chih"

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How tantalum proceeds phase change on tantalum nitride underlayer with sequential Ar plasma treatment
(2013-01-15)
Tsao, Jung-Chih
;
Liu, Chuan-Pu
;
Fang, Hsin-Chiao
;
Wang, Ying-Lang
;
光電學院
Tantalum can change its phase from high resistive beta-Ta to low resistive alpha-Ta phase on a TaN substrate with sequential Ar plasma treatment on the TaN layer surface prior to Ta deposition. The underlined mechanism of phase evolution is proposed based on systematic microstructure examination by high-resolution transmission electron microscopy. The images show that, with argon treatment, the upper part of the TaN film is transformed from amorphous-TaN to a composite phase of bcc-Ta(N) and amorphous-TaN mixture, which is also confirmed by X-ray diffraction patterns. The composite film composed of less nitrogen provides an ideal cubic matrix to confine the stable alpha-Ta phase to be grown. The alpha-Ta/bcc-Ta(N) film obtained by proper argon treatment results in film resistivity 10 times lower than the traditional Ta/TaN film. (C) 2012 Elsevier B.V. All rights reserved.
Microstructure and Formation of Copper Oxide in the Cu Electro-Polishing Process
(2010-11-01)
Kung, Te-Ming
;
Huang, Michael Rong-Shie
;
Tsao, Jung-Chih
;
Liu, Chuan-Pu
;
Wang, Ying-Lang
In this study, the formation of Cu oxide on Cu film is studied during Cu electropolishing in a phosphoric acid-based electrolyte with various Cu ion concentrations, from 2.28% to 10.08%. In cyclic voltammetry measurement, the maximum current density of the anodic peak (/(max)) decreases from 38.87 to 28.13 mA/cm(2) with increasing Cu ion concentration, indicating that an oxide film forms on the Cu film surface and the thickness increases with Cu ion concentration. Microstructures and crystallography of the oxide film are examined by transmission electron microscopy, which confirms the increase of the oxide film thickness due to the high Cu ion concentration in a H(3)PO(4) electrolyte. Three types of Cu oxide are detected using X-ray photoelectron spectroscopy, namely Cu(2)O, Cu(OH)(2), and CuO. With a Cu-ion electrolyte concentration of less than 6.99%, Cu(OH)(2) is dominant, while at higher Cu-ion concentrations, CuO predominates. The formation of CuO protects Cu from corrosion in the electrolyte with the Cu-ion concentration of over 6.99%.