Spectroscopic ellipsometer modulated by an external excitation

摘要

This invention concerns a spectroscopic ellipsometer modulated at a frequency ( omega m) intended for taking measurements of a sample (3). The spectroscopic ellipsometer is phase modulated, the sample being excited by external means (16) producing periodic, alternating excitation at a frequency ( OMEGA e). The measurement contains the ellipsometric parameter values ( psi , DELTA ) of the sample, respectively in the presence of ( psi 1, DELTA 1) and in the absence of ( psi 2, DELTA 2) excitation of the sample, as a function of excitation frequency ( OMEGA e).