Ion beam based composition and texture control of titanium nitride

Titanium nitride was formed by electron beam evaporation of titanium in an atmosphere of backfilled nitrogen. The growing film was simultaneously irradiated with argon ions. From of a single-aperture ion source, a Gaussian-shaped ion beam was extracted. Each position on the sample was correlated with a particular ion beam current density. With this method, on a single substrate a large variation in ion irradiation intensity could be obtained. Since the titanium evaporation rate was uniform over this area, the parameter varied over the sample surface was only the ion-to-atom arrival ratio. It turns out that with a constant Ti condensation rate and nitrogen impact rate, the Ti:N ratio in the film is a strong function of the argon ion impact rate. Ion-beam induced nitrogen sorption saturates at a certain ion irradiation intensity. While under all conditions the TiN (mono)phase is obtained, it shows different preferred crystal orientations in dependence on ion bombardment intensity. At low level, the film grows in (111)-orientation, at high levels in (100)-orientation. In a small transition zone, (110)-orientation prevails. Thus, the orientation can be selected by the ion beam intensity, which is relevant for application.