Journal of Vacuum Science & Technology A, Vol.21, No.6, 1981-1987, 2003
Experimental and computer simulation studies of the "baffled target" reactive sputtering process
Reactive sputtering is a technique widely employed for deposition of compound materials. One drawback encountered with this technique is that the target normally ends up in poisoned mode at reactive gas flow levels necessary for depositing a stoichiometric film, causing a severe drop of the deposition rate. To decrease the target poisoning a reactive sputter deposition technique based on the so-called baffled target has been suggested. In this configuration a target is confined in a box having a front aperture allowing sputtered material to be deposited through the aperture onto the substrate located in the main chamber. The purpose of this box is to separate the reactive gas in the chamber from the target thereby decreasing the target poisoning. We have carried out computer simulations as well as experimental studies on the baffled target technique. The computer simulations serve to explain the reactive gas gettering and the corresponding process behavior in the box and in the chamber, respectively. The calculations also assist in finding optimum operating conditions for this novel technique. It was found that it is possible to find operating conditions where compound film formation is achieved with the target in high rate metal mode at a supply level of reactive gas far below the level required to reach the hysteresis region. This is a unique property of the baffled target technique that may not be obtained in traditional reactive sputtering system configurations. (C) 2003 American Vacuum Society.