Imaging Ellipsometry - (PPT)

摘要

Ellipsometry is a powerful non-invasive microscopy technique. It is widely used in characterizing thin films, semiconductor industry and also in biotechnology. Ellipsometry uses the polarization change upon reflection on the sample surface in order to determine the film thickness. This technique is very sensitive, a spectroscopic setup can determine the complex dielectric constants of materials. A more straight forward setup with a single wavelength can already distinguish single atomic layers, provided the sample composition is know. An imaging ellipsometer uses a camera for detection instead of a photodiode or linear ccd. This makes it possible to measure a wide area in one measurement, a regular ellipsometer will need a time consuming scan over the surface or can only measure one spot. The imaging ellipsometer will be used to measure growth in a vacuum environment. For this purpose it is important to measure fast enough in order to record single atomic layer growth over an area slightly larger than the EUV spot size.