Self-consistent optical constants of SiC thin films

Area of Science:

• Materials Science
• Optics
• Thin Film Technology

Background:

• Optical constants are essential for designing optical coatings.
• Amorphous silicon carbide (SiC) films are promising materials for various optical applications.
• Existing optical data for amorphous SiC films is limited, especially across a broad spectral range.

Purpose of the Study:

• To measure and compile a comprehensive set of optical constants for ion-beam-sputtered amorphous SiC films.
• To extend the measured data to cover the visible to extreme ultraviolet (EUV) spectral range.
• To provide a self-consistent dataset for optical coating design.

Main Methods:

• Ellipsometry was used to measure optical constants in the 190-950 nm range.
• Literature data was integrated and extrapolated for a wider spectral coverage.
• Kramers-Kronig analysis was employed to ensure data self-consistency.
• Sum rules were used to estimate the global accuracy of the compiled data.

Main Results:

• Optical constants for amorphous SiC films were determined from the visible to the EUV spectrum.
• A bandgap of 1.9 eV was fitted for the amorphous SiC films.
• The compiled dataset is self-consistent and has good global accuracy.

Conclusions:

• This work provides the first comprehensive compilation of optical constants for amorphous SiC films.
• The dataset enables the design of multilayer coatings with tailored performance in both EUV and visible ranges.
• The findings support the use of amorphous SiC in advanced optical systems.