Real-time curvature and optical spectroscopy monitoring of magnetron-sputtered WTi alloy thin films

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• 作者：A. Le Priol ; L. Simonot ; G. Abadias ; P. Gu茅rin ; P.-O. Renault ; E. Le Bourhis
• 关键词：In situ optical spectroscopy ; In situ wafer curvature ; Magnetron sputtering ; Thin film growth ; WTi alloy
• 刊名：Surface and Coatings Technology
• 出版年：25 December, 2013
• 年：2013
• 卷：237
• 期：Complete
• 页码：112-117
• 全文大小：556 K

文摘

WTi thin films are known as potential adhesion promoters and diffusion barriers. WTi thin films were deposited by magnetron sputtering from an alloyed target (W:Ti ~ 70:30 at.%). Real-time surface differential reflectance (SDR) spectroscopy and wafer-curvature measurements were performed during deposition to study the growth and the film continuity threshold. SDR measurements during WTi deposition allow the determination of the change in reflectivity of p-polarized light (at Si substrate Brewster's angle) between WTi film and Si substrate in order to monitor layer growth. The comparison between experimental and simulated WTi SDR signals assuming a homogeneous and continuous layer growth shows that film continuity is ensured beyond a thickness of 4.5 卤 0.2 nm. Real-time wafer-curvature measurements allow the determination of the intrinsic stress development in the film. Two regimes are noticed during the growth up to the development of a compressive steady state stress. The early stages of growth are rather complicated and divided into sub-regimes with similar boundaries revealed by both in situ techniques. Deposition of an interfacial continuous layer different from WTi bulk is suggested by both in situ techniques below a thickness of 4.5 nm.