Model for prediction of coating composition deposited by sputtering using composite target in a reactive gas environment

Reactive sputtering is a widely used deposition technique for compound coatings. Ternary compound or multi component compound coatings are finding increasing applications due to their exotic properties. The properties of the coatings depend strongly on the composition of the films. A mathematical model has been developed to predict the composition of the metallic constituents of the coatings deposited by reactive sputtering using two metals composite target in the presence of a reactive gas (nitrogen) atmosphere. The model is worked out utilizing first order approximation and taking into consideration that there is no re-sputtering effect at the substrate. The model developed can also calculate the percentage of covered areas of the target surfaces (target poisoning) with reactive gas partial pressure. The model has been tested experimentally for titanium aluminum composite target in a nitrogen gas environment.