Characterization of Materials by Visible-Near UV Spectrophotometric and Spectroellipsometric Techniques

The primary advantages of optical measurements are that they are general, convenient, nondestructive, and can yield information about dynamic systems or processes in real time and in any transparent ambient. No special sample requirements are needed other than a reflecting surface, and measurements can be made with the sample in air or in atmospheric-pressure ambients. Nondestructiveness is obviously important for the analysis of unstable materials systems such as interfaces buried under oxide overlayers, while real-time capabilities suggest useful applications in process control. A final advantage is that optical probes offer unsurpassed energy resolution, important for accurately determining compositions of semiconductor alloys.