Evaluations of Diamond-Like-Carbon Film Optical Constants and Their Effects on Flying Height Determination

The accuracy in flying height determination of a film coated magnetic slider relies on the availability of accurate optical property values of each film. In view of this, the index of refraction and coefficient of extinction of carbon and underlayer films, as used on a magnetic slider, was evaluated in this study. Various thicknesses of carbon and underlayer films were coated on Al 2 O 3 -TiC substrates, and their optical properties were determined by using a variable angle spectroscopic ellipsometer at multiple angles of incidence and two optical models via reasonable range and least square methods. Then the effects of the carbon and underlayerfilms on flying height measurement were assessed. It was found that the optical properties of the underlayer film are strongly thickness and wavelength dependent. Therefore, the flying height measurement errors caused by incorrect treatment of the films are functions of film thickness and light wavelength.