In-situ Real Time Spectroscopic Ellipsometry Applied to the Surface Monitoring of Semiconductors

Abstract

AbstractA new kind of Real Time Spectroscopie Ellipsometer (RTSE) system is presented in detail. A multichannel analyser with photointensifier allows one to get spectroscopie measurements over the 0.25–0.85μm wavelength range with resolution λ/Δλ better than 500 and a good signal to noise ratio even for samples with poor reflectance. Precision and reproducibility of the system are around 0.3 and 0.1% for the two ellipsometric parameters. The measurement speed can be increased up to 15 spectra/s but must be adapted accurately to the process under control. An example of the heating process of a GaAs substrate measured in-situ by RTSE is presented and the temperature and native oxide thickness are deduced.