Hot target. Modeling of reactive sputtering

A non-isothermal physicochemical model for the reactive sputtering process is upgraded. The model is used for the description of hot metal target sputtering. The film synthesis on all surfaces of the vacuum chamber is given in a form of a surface chemical reaction. The target temperature is determined from the results of the discharge spectra measurement in the near-infrared region, and is approximated in the form of a function of the discharge current density. In order to provide a mathematical description of the reaction, the basic postulate of chemical kinetics taking into account the equation for Langmuir isotherm and the Arrhenius equation under nonisothermal conditions was used. The model incorporates thermionic emission and evaporation of the target surface. A system of eight algebraic equations describing the model is solved for titanium target sputtering in a nitrogen environment at a current density of 25–600 A/m$^2$. It has been shown that the target heating shifts the critical operating points of a target to the lower nitrogen flow rate region and reduces the width of the hysteresis loop as compared to a cold target. The influence of the target evaporation on the process appears at a current density exceeding 400 A/m$^2$.