| Popis: |
Measuring properties of ultrathin optical films is based on optical interference. Ultrathin films are very challenging to test, because their thicknesses are far smaller than the measuring wavelength, so very little phase shift can be detected. In this work, test sensitivity and accuracy are improved by a rigorous algorithm in which all unknowns {n,k,t} in their full space are fit together without approximations and presumptions. As a result, a software for variable-angle spectroscopic ellipsometer (VASE) data fitting was developed. It gives very reliable ultrathin-film measurement down to 2.5 nanometers. The software not only improves the reliability, accuracy of {n,k,t} measurement, but it also extends VASE capabilities to characterize a film’s optical quality. |
