<title>Optical properties of ion-implanted laser-annealed Si studied by spectroscopic ellipsometry</title>

Abstract

In this research, spectroscopic ellipsometry (SE) was used to study effects of heavy doping on the optical properties of n-type Si. The Si samples investigated were ion-implanted at 100 keV with phosphorus dose ranging from 6 X 1014 to 6 X 1016 cm-2 and annealed using a KrF excimer laser in the nitrogen environment. SE measurements were carried out in room air, in the wavelength range from 250 to 850 nm. In the spectral analysis for each sample, a two-layer fitting model was used, in which the effects of the native oxide were included and the optical properties of ion-implanted laser-annealed Si were represented by a set of five Lorentz harmonic oscillators. Excellent agreement was obtained between the measured and calculated spectra, indicating that the model used was adequate and that the calculated results were reliable. Using the dielectric function data obtained from the model calculations, the E1 and E2 critical point (CP) energies were obtained by fitting the second derivative of the imaginary part of the measured dielectric function to a standard analytic lineshape, from which the doping-induced shift at the two CP's was determined.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.