Momentum transfer driven textural changes of CeO2 thin films

The influence of the target erosion depth on the film texture was investigated during DC reactive magnetron sputter deposition of CeO2 thin films. Three fluxes towards the substrate surface (the relative negative oxygen ion flux, the material flux, and the energy flux) were measured and related to the ongoing erosion of a cerium target. As the deposition rate increased for more eroded targets, both the energy flux and the negative ion flux decreased. Cerium oxide thin films that were deposited at different target erosion states, exhibited a change in preferential crystalline orientation from [200] to [111]. This textural change cannot be explained in terms of the energy per arriving atom concept. Instead, it is shown that the momentum of the high energetic negative ions is an essential condition to clarify the witnessed trends.