Process modeling of reactive sputtering

Reactive sputtering is a very complex and nonlinear process. There are many parameters involved. Normally it is not possible to vary a single parameter independently of the others. It is therefore very difficult to characterize the process based on experimental observations. A better understanding of the reactive sputtering mechanism is needed. We have suggested a simple model for the reactive sputtering process. This model is primarily based on well-known gas kinetics, transferred to this application. With this model it is possible to theoretically predict different processing conditions and actually study the influence of a change in an individual parameter value. The results may then be used to predict optimal experimental conditions. With this technique it is also possible to study means of affecting the well-known hysteresis effect. This article is specially devoted to explain the width of the hysteresis region and how it is affected by the sputtering intensity. Experimental results are presented that support the validity of the proposed model. It was found that the hysteresis width increases in proportion to the rf power fed to the sputtering target. It is thus not possible to eliminate the hysteresis effect by any kind of variation of the sputtering intensity.The effect of the hysteresis effect on the composition limitation of the deposited films will also be described.