Statistical evaluation of refractive index, growth rate, hardness and Young's modulus of aluminium oxynitride films

Aluminium oxynitride films were produced by reactive dc-magnetron sputterin g with compositions covering the concentration range from nitride to oxide. The altered deposition parameters were the sputtering power and the gas fl ow rates of argon, nitrogen and oxygen. The refractive index and the growth rate of the films were determined by spectroscopic ellipsometry, which sho wed negligible absorption. With indentation by a nano hardness tester the h ardness and the Young's modulus of the films were obtained. The results of these measurements were evaluated by statistical software. The dependences of the physical properties on the deposition parameters and on the film thi ckness were evaluated and quantified. The thickness still had some influenc e on the results of the nano-indentation measurements resulting from the in fluence of the substrate. Furthermore, the dependences of the physical prop erties on the him composition represented by the oxygen content and the fil m thickness were evaluated. However, these evaluations only delivered usefu l results for the refractive index and the hardness. it is shown that the p hysical properties of aluminium oxynitride films can be controlled by utili sing design of experiment and evaluation with statistical software, deliver ing the correct deposition parameters. For all of the mentioned properties graphs are given depicting actual measurement results of 26 evaluated films . (C) 1999 Elsevier Science S.A. All rights reserved.