Modeling of Reactive Sputtering—History and Development

Abstract

This work critically reviews the evolution of reactive sputtering modeling that has taken place over the last 50 years. The review summarizes the main features of the deposition of simple metal compound films (nitrides, oxides, oxynitrides, carbides, etc.) that were experimentally found by different researchers. The above features include significant non-linearity and hysteresis. At the beginning of the 1970s, specific chemisorption models were proposed. These models were based on the assumption that a compound film was formed on the target due to chemisorption. Their development led to the appearance of the general isothermal chemisorption model, which was supplemented by the processes on the surfaces of the vacuum chamber wall and the substrate. The model has undergone numerous transformations for application to various problems of reactive sputtering. At the next step in the development of modeling, the reactive sputtering deposition (RSD) model was proposed, which was based on the implantation of reactive gas molecules into the target, bulk chemical reaction, chemisorption, and the “knock-on effect”. Another direction of the modeling development is represented by the nonisothermal physicochemical model, in which the Langmuir isotherm and the law of mass action are used. Various modifications of this model allowed describing reactive sputtering processes in more complex cases when the sputtering unit included a hot target or a sandwich one.

On the role of chemisorption in the formation of the target surface compound layer during reactive magnetron sputtering

“…Knock-on, and by extension direct, ion implantation of reactive gas species are therefore essential processes to be included in any reactive sputtering model. Hence, the conclusion by Shapovalov [1] that "The results presented by the authors of the RSD model are interesting, but they do not make it possible to assess the state of the target." seems not justified, and are based on a wrong interpretation of the equations within the RSD model.…”

“…In a recent review on the history of modeling of the reactive sputtering process, several models are presented and compared [1]. The paper first presents some often used terminology such as hysteresis, the metallic and reactive mode.…”

A Coaxial Nozzle Attachment Improving the Homogeneity of the Gas Flow Sputtering

“…Sputtering is one of the most significant deposition methods utilized for depositing thin films across various applications (industrial coatings on glass, wear-resistant coatings, photovoltaics, electronics and others) [1][2][3]. Among the sputtering techniques, magnetron sputtering is widely employed in the industry but is prone to target poisoning due to hysteresis behavior during reactive sputtering, which also impacts the deposition rate [4][5][6]. Gas flow sputtering (GFS), based on hollow cathode discharge, demonstrates several key advantages over conventional low-pressure sputtering techniques.…”