Silicon carbide synthesized by RF magnetron sputtering in the composition of a double layer antireflection coating SiC/MgF2

Abstract

In this paper, the optimal thickness of SiC film for an antireflection coating was determined by computer simulations using Lumerical FTDT and SCOUT software. The simulation was carried out for the SiC/MgF₂ system, where silicon carbide films were deposited at a magnetron power of 100, 150, 200, 250 W, while the thickness of the magnesium fluoride films remained unchanged and amounted to 130 nm. The simulation results showed that the optimal parameters for the synthesis of SiC antireflection layer are 100 W/50 nm. With these parameters, the reflection is less than 3% in the widest wavelength range of 475–1020 nm. The dependence of the physical properties of the synthesized films on the power of the magnetron is investigated. Using reflection and transmission spectroscopy it was experimentally revealed that a decrease in the magnetron power from 250 to 100 W leads to a decrease in the refractive index. According to our results the best antireflection effect can be achieved with SiC/MgF₂ coatings when SiC films are deposited at 100 W magnetron power. The reflectance spectra are consistent with the simulation spectra, especially in the 475–1020 nm range, where the surface reflects only 0.2–3.0% of the incident light. The obtained results are explained by the correlation between the structural properties, composition of amorphous silicon carbide films and antireflection properties.