Growth, structure and stress of sputtered TiB2 thin films

Thin hexagonal TiB2 films were deposited using d.c. magnetron sputtering. The structure of films with different thicknesses was evaluated by X-ray diffractometry and transmission electron microscopy. It was found that the microstructure of TiB2 films depends on thickness. Films below approximately 1000 إ are made up of randomly oriented fine grains. A (001) texture starts to develop above this thickness. More detailed study of the texture reveals that the textured crystallites align more ideally as the thickness of films increases. The residual stresses in all films are compressive and increase slightly with increasing film thickness. After 400 °C annealing, the film stress systematically shifts toward the tensile direction with the thinner films exhibiting larger changes. This is attributed to the elimination of a larger density of defects and more pronounced grain growth in thinner films.