Optical characterization of diamond-like carbon films

In this contribution, the results achieved by the optical characterization of diamond-like carbon (DLC) films are presented. A multi-sample modificati on of variable angle of incidence spectroscopic ellipsometry (VASE) is used to determine the values of the thicknesses and spectral dependences of the optical constants of these films. It is shown that this optical method is very suitable for characterizing the films studied because the influences o f some defects of these films are suppressed within this method. Further, t he spectral dependences of the optical constants determined for the DLC fil ms studied are interpreted using a new model of dispersion based on the exi stence of two oscillators corresponding to both the pi --> pi* and sigma -- > sigma* interband transitions, Within this model of dispersion of the opti cal constants, the concept of the band gap is respected as well. (C) 2001 E lsevier Science Ltd. All rights reserved.