Modeling of reactive sputtering and evaporation in a hot-target magnetron discharge

Abstract

We theoretically consider the joint influence of hot-target effects and the pulsed nature of the discharge on the state of the target surface. We enhance the previously modified time-dependent Berg model by taking into account the evaporation of target material as well as the influence of target temperature on the rate of chemical reactions on its surface. The system of equations describes the state of the target in terms of poisoned area fractions θ1 and θ2, where index 1 corresponds to the monoatomic surface layer, and index 2 – to the layer beneath the surface (subsurface layer). The processes of chemisorption on target surface, sputtering of reactive gas atoms from target, implantation of reactive gas ions to the sub-surface layer, material evaporation, and transfer between the layers are considered. A separate equation connects the atomic fluxes of reactive gas associated with target and substrate surfaces with the volumetric characteristics, such as gas injection rate and pumping speed. The system of equations is solved numerically, and test results are presented.