Estimation of Various Methods to Measure the Optical Phase Delay of the Slider Air Bearing Surface with Protection Layers.

Abstract

It is difficult to precisely identify the phase delay of reflecting light from the slider surface with ABS (air bearing surface) protection layers, since the ABS protection layer has complex optical constant and ABS surface is very small. The ellipsometer is widely used to measure the phase delay, but it proved that ellipsometer can not measure precise phase delay of some ABS protection layer. Therefore, in this paper, other measurement methods are researched and tested to measure that phase delay. First is "graph method", the phase delay is calculated from the total reflectivity of different incident angle. The second is "kramers-kronig" method which calculate the phase delay from the reflectivity distribution. The last method is "calculation method", the phase delay is calculated from the optical constants of the ABS protection layers and the slider. The conclusion is that "calculation method" is ideal, but difficult, then it is recommendable that using ellipsometer and "graph method" to supplement each other.