High-Precision Analysis of Oxygen Depth Profile in 16 O + -Implanted Silicon Substrates by Spectroscopic Ellipsometry

Abstract

A precise method of analyzing oxygen depth profiles in oxygen-ion -implanted Si substrates by spectroscopic ellipsometry has been developed. The specimens were formed by -implantation into Si(111) with oxygen doses ranging from 3 to at 180 keV. The optical characteristics such as the amplitude ratio angle (Ψ) and phase difference angle (Δ) vs. wavelength (λ) of the specimens were measured by spectroscopic ellipsometry. The -implanted Si layer was modeled as a transition layer, which was composed of crystalline Si and and the composition ratio of crystalline Si to was assumed to change continuously in a direction toward depth. In the model the Ψ-λ and Δ-λ spectra were calculated reversely by using the effective medium approximation analysis method. In the simulation fitting was performed to correlate the measured characteristics. The simulated oxygen depth profile and the modeled layer structure were compared with actual results obtained by Rutherford backscattering spectroscopy and cross-sectional transmission electron microscopy. This method can obtain oxygen depth profiles in -implanted Si substrates easily and nondestructively with a higher precision compared to conventional techniques. © 2004 The Electrochemical Society. All rights reserved.