Ellipsometry for correct determining the void fraction and true refractive index of thin films

Using two measurements in vacuum and under condition for condensing water, one might more correctly to determine the true refractive index N-true and porosity (void fraction) Q with Bruegeman's EMA. The characteristics of chamber-attachment to ellipsometer, algorithm and application samples of new method for SiO2, ZrO2, HfO2, a-C:H, and In2O3-SnO2 films are presented, It is found the differences between measurements of an effective refractive index N-ef in air, in vacuum sind with condensed water may be up to 0.09. The void fraction for these films are range from 0 to 0.277. Difference between N-true and N in air may up to 0.306.