DETERMINATION OF SMALL FLUCTUATIONS IN ELECTRON-DENSITY PROFILES OF THIN-FILMS - LAYER FORMATION IN A POLYSTYRENE FILM

A spin-coated thin polystyrene film on a silicon single crystal has be en studied using the X-ray reflectivity technique. Signature of layeri ng as a function of depth, due to confinement, in this polystyrene fil m could be detected from the reflectivity profile using a new analysis scheme. Small variations of electron density across the depth of a th in film can be determined from reflectivity data using this scheme wit h no a priori distribution of electron density profile.