STUDY ON DC MAGNETRON SPUTTER-DEPOSITION OF TITANIUM ALUMINUM NITRIDETHIN-FILMS - EFFECT OF ALUMINUM CONTENT ON COATING

Titanium aluminium nitride thin films have been deposited on glass sli des using a dual unbalanced d.c. magnetron sputter arrangement with se parate titanium and aluminium targets. A range of Ti/Al/N compositions were produced by varying the aluminium target magnetron current. The thin films were then examined using an atomic force microscope (AFM) a nd a held emission scanning electron microscope. Aluminium, titanium a nd nitrogen compositions (wt.%) were determined by using energy disper sive X-ray spectroscopy. It was found that as the aluminium magnetron current increased from 0.1 to 0.4 A, the titanium decreased from 77 wt .% to 53 wt.%, the aluminium increased from 6 wt.% to 25 wt.% and the colour changed from gold to a blue-grey. An increase in the aluminium content had a significant effect on the grain size of the film. Surfac e measurement analysis using the AFM results revealed that as the alum inium content increased both the rms roughness (6.5 nm-->3.2 nm) and g rain size (120 nm-->90 nm) decreased. It is believed that the above ef fects could result from the increase in aluminium atom bombardment rat e with the higher aluminium magnetron current.