AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF+VM-MoM

Paper TF+VM-MoM4
High Rate Reactive DC Magnetron Sputtering of Al Oxide and W Oxide Thin Films; Large Area Coatings

Monday, October 25, 1999, 9:20 am, Room 620

Session: Advances in Hard and Superhard Coatings I
Presenter: M.K. Olsson, Fraunhofer Institute for Solar Energy Systems, Germany
Authors: M.K. Olsson, Fraunhofer Institute for Solar Energy Systems, Germany
K. Macák, Linköping University, Sweden
Correspondent: Click to Email
Recently we reported stable high-rate deposition of Al oxide with any composition, including stoichiometry, utilizing a conventional reactive DC magnetron sputter system in laboratory scale.@footnote 1,2@ Due to the proper system geometry, including large enough target-to-substrate distance, and/or sufficient process gas pressure, it was possible to keep the target in the metallic mode by taking advantage of the scattering of the sputtered Al atoms through the inert gas. Moreover, the relatively high working pressure caused an increase in the back-deposited Al atoms to the non-eroded areas of the target, thus keeping these areas conducting, thereby avoiding arcing, without requiring the use of any other devices. We have applied this concept to a sputtering system considered for large area thin film production. A construction for increasing the cathode-to-sample length was designed with our technical possibilities in mind. After installation the desired O/Al arrival ratio was obtained and it was possible to produce stoichiometric aluminum oxide with an order-of-magnitude higher deposition rate. Choice of a sufficient pressure was crucial for the long-term stability of the process.@footnote 3@ Once the target is in the metallic state one may increase the growth rate linearly by increasing the target current. However, the experiments and analysis of the deposition process based on MC simulation of sputtered particles transport extended by Rossnagel's model of gas heating@footnote 4@ confirmed that the efficiency of the gas scattering process is for heavy elements partially eliminated at high discharge currents. To deal with this, we applied our concept of proper choice of process conditions for sputtering to less reactive materials with relatively high atom mass. It was possible to improve the sputtering condition for making films of stoichiometric amorphous W oxide at relatively high target current.@footnote 5@ @FootnoteText@ @footnote 1@M. Kharrazi Olsson, K. Macák, U. Helmersson, and B. Hjörvarsson, J. Vac. Sci. Technol. 16, 639 (1998). @footnote 2@K. Macák, T. Nyberg, P. Macák, M. Kharrazi Olsson, U. Helmersson, and S. Berg, J. Vac. Sci. Technol. 16, 1 (1998). @footnote 3@M. Kharrazi Olsson, K. Macák, W. Graf, Submitted. @footnote 4@S.M. Rossnagel, J. Vac. Sci. Technol. 6, 19 (1988). @footnote 5@M. Kharrazi Olsson, K. Macák, Submitted.