Theoretical Study Of Measuring Gratings Parameters With Ellipsometry

Ellipsometry based on polarized transformation, beams of light reflecting and transmitting on the thin films, is the method which inverse ellipsometric parameters processed by computers to obtain various of optic parameters of measured thin films. Although a few researchers have discussed ellipsometric parameters of gratings on theory and experiment. Ellipsometry that is applied to lots of fields such as Physics. Chemistry. Hylology. Photography. Biology, etc. owing to many merits has not yet been used to measure parameters of gratings. The paper researches on the subject in view of current lack of it.The main tasks of the paper include: analyzing ellipsometric characteristics of gratings in detail with vector diffraction theory and ellipsometrics; devising a reflective quarter wave plate at normal incidence according to some ellipsometric characteristics; making use of normal simplex algorithm during ellipsometric inversion of gratings parameters, inversing ellipsometric parameters with Gaussian noise of different standard deviations to simulate actually measured values with examples of isotropic metallic and anisotropic step gratings and testing that ellipsometry about gratings parameters is feasible with the range of certain precision; discussing choice of incidence angle at length.