Theoretical sputtering yields of Al and Mg targets in physical vapor deposition processes

Calculations of sputtering yields are performed for aluminum and magnesium target materials with the use of a homemade software based on the analytica l expression of Garcia-Rosales. The theoretical yield of magnesium is about twice the value related to aluminum in accordance with the experimental ra tio of the Mg/Al deposition rates. We show that the deposits of the same ma terials must be subjected to densification followed by resputtering phenome na when a bias voltage is set to the substrates. These predictions are conf irmed by atomic force microscopy observations, especially for magnesium dep osits owing to their texture and the high sputtering yield of this material . (C) 2001 American Vacuum Society.