A physical model for eliminating instabilities in reactive sputtering

Reactive sputtering is an attractive method for preparing compound films like nitrides and oxides. However, one drawback is that the process often switches between the metal mode and the compound mode. This means that it is very difficult to obtain films with an intermediate composition. In a recently presented model for reactive sputtering we have been able to predict most observed effects including the hysteresis effect. In this paper we have investigated the effect of the pumping speed on the nonstable transition region. We have been able to show that, if the pumping speed is high enough, there is a smooth transition between the different sputtering modes. The hysteresis will also disappear. We will also present a method that can be used to calculate the limiting value for the pumping speed in order to obtain a smooth and stable transition region.