AVS 53rd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS1-FrM

Paper PS1-FrM12
Evaluation of Sticking Probability of Ti Atoms in Sputtering Deposition

Friday, November 17, 2006, 11:40 am, Room 2009

Session: Plasma-Surface Interactions III
Presenter: N. Nafarizal, Nagoya University, Japan
Authors: N. Nafarizal, Nagoya University, Japan
K. Sasaki, Nagoya University, Japan
Correspondent: Click to Email
Knowledge on sticking probability is essential in predicting the deposition profile of a thin film inside a fine trench and a fine hole. In numerical simulations of the deposition profile, the sticking probability of metal atoms is widely assumed to be unity, but to our knowledge, there is no reliable experimental evidence of that. In this work, we evaluated the sticking probability of Ti atoms in magnetron sputtering deposition experimentally. We measured the spatial distribution of the Ti atom density in the discharge region sandwiched by a Ti target and a substrate by laser-induced fluorescence imaging spectroscopy. It was found that the Ti atom density on the substrate was not zero, clearly indicating that the sticking probability of Ti is less than unity. The magnitude of the sticking probability was evaluated by comparing the spatial distribution of the Ti density with a diffusion model proposed by Chantry (P. J. Chantry, J. Appl. Phys. 62, 1141 (1987)). The Chantry's model includes the diffusion coefficient and the gas temperature. The diffusion coefficient was obtained from a literature (D. Obhesian, et al., Opt. Comm. 32, 81 (1980)), and the gas temperature was evaluated from the Doppler-broadened linewidth of an Ar metastable state. As a result, the sticking probability was evaluated to be 0.4-0.5. The sticking probability was almost independent of the discharge power and the gas pressure. In addition, similar sticking probabilities were observed when the substrate was heated up to 520 K and when an rf bias corresponding to a self bias voltage of 200 V was applied to the substrate.