Principal Physics of Oblique Sputtering of Calcium Phosphate Coatings Using RF-Magnetron Discharge Plasma

A possibility in principle is determined for the titanium surface functionalization by oblique sputtering of nanostructured bioactive calcium phosphate coatings. The coatings are deposited by the RF magnetron sputtering of the targets based on hydroxyapatite and antibacterial zinc-substituted hydroxyapatite. The coating morphology and their growth characteristics are studied as a function of such process parameters as the specimen tilt angle with respect to the particle flux from the source, the supplied power, and the distance from the target plane to the specimen surface. As the tilt angle is increased, the coating surface morphology significantly changes and represents nanosized structural elements oriented towards the particle source and ordered in accordance with the substrate surface morphology prior to sputtering. The inner coating structure consists of columnar elements tilted to the substrate plane.