RAMAN-BASED MEASUREMENTS OF OPTICAL-PROPERTIES OF THIN SOLID FILMS - APPLICATION TO AMORPHOUS DIAMOND

The potentialities of Raman spectroscopy to measure optical properties of thin solid films are considered. A new approach based on the analy sis of interference-induced modification of the Raman scattering from the substrate material together with the normal reflection coefficient is proposed. It is shown that the method provides the absorption coef ficient and refractive index of the film bulk with high spatial resolu tion and accuracy, and it can be applied to various transparent thin f ilms. The developed approach is used to measure optical properties of amorphous diamond films deposited onto crystalline silicon. In the cas e of the amorphous diamond films deposited with a mass-separated ion b eam, a straightforward correlation between the absorption coefficient and Raman spectra is obtained, which can be also used to estimate the optical properties. For the films deposited with pulsed cathodic are d ischarge, such a relation appears to be more complex, which possibly i ndicates extensive variations of the sp(2) clusterization in the latte r deposition method. (C) 1998 Elsevier Science S.A. All rights reserve d.