Optical conductivity of Ni1−xPtxSi monosilicides (0 < x < 0.3) from spectroscopic ellipsometry

Abstract

The optical constants of 22 nm thick Ni 1Àx Pt x Si (0 < x < 0.3) monosilicide films were measured using spectroscopic ellipsometry, in the spectral range from 0.6 to 6.6 eV at room temperature. Ni 1Àx Pt x films sputtered on clean Si were annealed at 500 C for 30 s to form nickel platinum monosilicides. The correct silicide thickness was found by minimizing Si substrate artifacts in the optical constants of Ni 1Àx Pt x Si determined from ellipsometric data analysis. Two interband transitions at 1.8 and 4.5 eV were observed (rather than three peaks in PtSi). The absorption peak at 4.5 eV broadens with increasing Pt content in the monosilicide.