The effect of grain size and phosphorous-doping of polycrystalline 3C-SiC on infrared reflectance spectra

► IR is investigated as a technique to measure grain size and P-doping of polycrystalline SiC. ► Infrared plasma minima can be used to determine doping levels in 3C-SiC for doping levels greater than 5 × 1017 cm−3. ► A linear relationship is found between FWHM and the inverse of grain size of 3C-SiC irrespective of P-doping level. ► It is further found that ωp is not influenced by the grain size. ► P-doping level has no significant effect on the linear relationship between grain size and surface roughness.