A New Technique for Measuring Thickness of Thin Solid Films

A new technique has been developed for measuring the thickness parameter for any thin solid films. Various thin films of silver, aluminium and antimony have been prepared by using vacuum evaporation plant at the vacuum of 10−5 torr. The films have been scratched by a fine metal pin. By employing a semi-silvered cylindrical convex lens, a point contact has been established between a silvered scratch-film and a cylindrical lens. Multiple beam Fizeau interference fringes have been obtained over the surface of thin films. Across the step of the scratch, because of height difference, the shift in the fringes have been observed. Due to the axis of point contact, no ambiguity in allocation of ringe order has been obtained. The thicknesses of silver, aluminium and antimony thin films have been determined very precisely. The technique gives high resolution with a good degree of reproducibility and implications are discussed.