Glancing angle deposition to modify microstructure and properties of sputter deposited chromium thin films

The glancing angle deposition (GLAD) technique was used to deposit chromium thin films by dc magnetron sputtering. With suitable operating conditions to favour a columnar microstructure and by controlling the orientation of the substrate relative to the impinging vapour flux, an inclined columnar film microstructure was produced. A systematic change of the angle ‘α’ between the incident atom flux and the substrate normal was correlated with the angle ‘β’ between the columnʹs axis and the substrate normal. For every angular range (α increases from 0 to 50°), the results were corroborated with empirical relationships between angles α and β. The influence of the deposition at oblique incidence on the surface morphology and the microstructure was investigated by atomic force microscopy and by scanning electron microscopy. The evolution of the crystallographic structure was also examined by X-ray diffraction vs. the angle of the incident flux. Measurements of the conductivity and nano-indentation tests were also performed in order to discuss the change of the mechanical and electrical behaviours, as a function of the orientated microstructure of the coatings.