On the influence of local oxygen addition on the growth of sputter deposited yttrium oxide thin films

Abstract

Yttrium oxide thin films are grown by reactive magnetron sputtering. To achieve a high deposition rate, target poisoning is avoided by local oxygen addition at the substrate. In all deposited thin films only the monoclinic Y2O3 phase is observed. A strong variation in the film texture across the sample for experiments with a stationary sample stage is noticed. This inhomogeneity can be partially traced back to an uneven oxygen gas distribution. Sample rotation resolves this problem, but still the gas distribution influences both the texture and the Bragg peak positions. Several configurations for the gas supply are tested with a different number of gas distribution pipes. An overview of all experiments shows an interesting correlation between the texture coefficient and the peak position of the monoclinic (111) Bragg reflection. When the peak shifts towards higher diffraction angles, the texture coefficient drops as a higher contribution of the 402¯ orientation is observed. This trend however is further complicated by the exact geometrical configuration on the deposition rate, and the energy/momentum of the species arriving at the substrate. As previously reported, an increasing energy/momentum per deposited atom results in monoclinic thin films with a preferential (111) out-of-plane orientation.