Journal of Process Control, Vol.83, 121-128, 2019
Model approximation and stabilization of reactive sputter processes
The aim of this paper is to present a control design method for nonlinear reactive sputter processes to increase the process speed and to facilitate the deposition of stoichiometric thin films. A physical model originating the fields of thin films science and vacuum science is analyzed to develop a control-oriented model, which describes the process with respect to a reactive gas as input and the pressure as output. The model parameters are identified by experiments. A control design method is proposed to stabilize the unstable operating points of the process. Experiments for the validation of the model and the controller are given. They show that reactive sputter processes can be modeled with sufficient accuracy by a first-order nonlinear differential equation and can be controlled by a linear feedback controller. (C) 2018 Elsevier Ltd. All rights reserved.