Measurement of flying height with carbon overcoated sliders

Ellipsometry is used to characterize the phase shift on reflection off carbon-overcoated sliders in order to accurately determine slider flying height with interferometry. A simplified analysis is used to approximate the phase shift based on a single ellipsometric measurement of the finished slider. A rigorous analysis indicates that for the overcoating systems studied herein, the flying height error introduced by the simplified analysis of phase shift on reflection was less than one nanometer. Experimental measurements of spacing with an overcoated slider resting on deposited bumps on a stationary disk indicate that the average measured spacing was within one nanometer of the bump height