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.