Characterization of thin TiSi 2 films by spectroscopic ellipsometry and thermal wave analysis

Abstract

Thin TiSi 2 films were prepared using conventional and advanced technological processing schemes. The formation of silicide films was monitored by a number of analytical techniques including 4-point probe, profilometry, X-ray diffraction, cross-sectional TEM, and atomic force microscopy. The data are compared with measurement results obtained by spectroscopic ellipsometry and by thermal wave analysis on the same samples. The capabilities of optical methods for measurement of silicide film parameters such as film thickness, film uniformity, and phase transition are evaluated. It is shown that spectral ellipsometry can be used for thickness measurement of thin silicide layers if appropriate models for data evaluation are used. Thermal wave analysis can be used for characterization of layer thickness uniformity as well as for phase formation monitoring. However, thermal wave analysis requires an appropriate calibration of the thermal wave signal as a function of desired measurement parameters. Both optical techniques used are fast, non-contact, and non-destructive and can therefore be used for in-line process control of silicide processing in semiconductor manufacturing.