SPECTROSCOPIC ELLIPSOMETRY DATA-ANALYSIS - MEASURED VERSUS CALCULATEDQUANTITIES

Spectroscopic ellipsometry is a very powerful technique for optical ch aracterization of thin-film and bulk materials, but the technique meas ures functions of complex reflection coefficients, which are usually n ot of interest per se. The interesting characteristics, such as film t hickness, surface roughness thickness and optical functions can be det ermined only by modeling the near-surface region of the sample. Howeve r, the measured quantities are not equivalent to those determined from the modeling. Ellipsometry measurements determine elements of the sam ple Mueller matrix, but the usual result of modeling calculations are elements of the sample Jones matrix. Often this difference is academic , bur if the sample depolarizes the light, it is not. Ellipsometry cal culations also include methods for determining the optical functions o f materials. Data for bulk materials are usually accurate for substrat es, but are not appropriate for most thin films. Therefore, reasonable parameterizations are quite useful in pet-forming spectroscopic ellip sometry data analysis. Recently, there has been an increased interest in anisotropic materials, both in thin-film and bulk form. A generaliz ed procedure will be presented for calculating the elements of the Jon es matrix for any number of layers, any one of which may or may not be uniaxial. (C) 1998 Elsevier Science S.A.