Neutron reflectivity investigation of the effects of harsh environments on Ta sub(2)N thin films

We use neutron reflectivity to study the effects of harsh environments on the composition and structure of Ta sub(2)N films. We investigated samples with a 700 angstroms Ta sub(2)N layer, annealed in vacuum, hydrogen, and air, in an attempt to simulate the effects of aging on Ta sub(2)N thin films. We obtained good model/data fits for all samples studied, with the exception of the air annealed sample - inhomogeneities and cracking reduced the quality of this fit. A 90 angstroms thick layer of TaH sub(x) was found on top of the hydrogen annealed sample, with no evidence of hydrogen enrichment at the Ta sub(2)N/SiO sub(2) interface. Furthermore, we found that air annealing produces a approximately 2000 angstroms thick layer of tantalum oxide.