ANALYSIS OF CRITICAL-POINTS IN SEMICONDUCTOR OPTICAL FUNCTIONS FROM IN-SITU AND REAL-TIME SPECTROSCOPIC ELLIPSOMETRY

In this study, dielectric functions of sufficient quality for analyses of band structure critical points (CPs) have been obtained from high speed spectroscopic ellipsometry measurements performed using a multichannel instrument during semiconductor preparation and processing. This new capability has been applied to crystalline Si materials whose dielectric functions are modified by finite size effects resulting from electron scattering at surfaces and grain boundaries. First, we have determined the particle size dependence of the CP parameters for isolated Si microcrystals from an analysis of ellipsometric spectra collected in real time during preparation by plasma-enhanced chemical vapor deposition. The resulting information has also been applied to characterize the near-surface structure of a recrystallized Si substrate processed by diamond polishing-annealing steps and measured in situ prior to diamond deposition.