An Overview of Ellipsometric Measurements for Nonplanar Surfaces

Ellipsometry is an optical method used for characterizing materials and thin films. The principle of ellipsometry is that it measures polarization
changes at a sample in a reflection or transmission configuration. However, the shape of the sample is limited to flat or nearly flat surfaces because ellipsometry is sensitive to the angle of incidence, tilt angle and the sample position (height). Even slight misalignment of the sample might lead to significant experimental errors. For large misalignment, the detector of the ellipsometer is not feasible to receive sufficient signals. There have been a few approaches for characterizing nonplanr surfaces by ellipsometry. This report gives an overview of these approaches for ellipsometric measurements of nonplanar surfaces.