| abstract |
Method and apparatus for controlling the growth of a multispecies film. During film growth, an ellipsometer (40, 52, 54, 62, 64, 70, 72) continuously monitors the surface (24) on which the film is growing. The ellipsometer data is used to calculate (38) the effective complex dielectric constant of the thin film / substrate structure. A sequence of these data is used in a calculation model to determine the composition of the upper part of the thin film. The composition measured is compared with the expected composition and the quantity of one of the species supplied is modified accordingly (26). |