Glancing angle deposition of Zn-doped calcium phosphate coatings by RF magnetron sputtering

Zn-substituted hydroxyapatite with antibacterial effect was used in radiofrequency (RF) magnetron deposition of calcium phosphate coating onto Ti- and Si-inclined substrates. The development of surface nanopatterns for direct bacteria killing is a growing area of research. Here, we combined two approaches for possible synergetic antibacterial effect by manufacturing a patterned surface of Zn-doped calcium phosphate using glancing angle deposition (GLAD) technique. A significant change in the coating morphology was revealed with a substrate tilt angle of 80°. It was shown that an increase in the coating crystallinity for samples deposited at a tilt angle of 80° corresponds to the formation of crystallites in the bulk structure of the thin film. The variation in the coating thickness, uniformity, and influence of sputtered species energy on Si substrates was analyzed. Coatings deposited on tilted samples exhibit higher scratch resistance. The coating microand nano-roughness and overall morphology depended on the tilt angle and differently affected the rough Ti and smooth Si surfaces. GLAD of complex calcium phosphate material can lead to the growth of thin films with significantly changed morphological features and can be utilized to create self-organized nanostructures on various types of surfaces.