Spectroscopic phonon and extended x-ray absorption fine structure measurements on 3C-SiC/Si (001) epifilms

Highlights: • Vibrational and structural properties are reported for 3C-SiC/Si (001) epilayers prepared by V-CVD method. • Phonon characteristics are assessed by Raman scattering and infrared reflectance spectroscopies. • Local inter-atomic structures are estimated by polarization dependent synchrotron radiation x-ray absorption fine structure. • Bruggeman's effective medium theory is applied to explicate the observed unusual infrared reflectance features in 3C-SiC/Si (001). • Bi-axial stress in 3C-SiC epifilms is estimated to be an order of magnitude smaller while the strains are two-orders of magnitude lower than the lattice misfits of bulk 3C-SiC and Si crystals. Comprehensive experimental and theoretical studies are reported to assess the vibrational and structural properties of 3C-SiC/Si (001) epilayers grown by chemical vapor deposition in a vertical reactor configuration. While the phonon features are evaluated using high resolution infrared reflectance (IRR) and Raman scattering spectroscopy (RSS) – the local inter-atomic structure is appraised by synchrotron radiation extended x-ray absorption fine structure (SR-EXAFS) method. Unlike others, our RSS results in the near backscattering geometry revealed markedly indistinctive longitudinal- and transverse-optical phonons in 3C-SiC epifilms of thickness d 0.4 μm. The estimated average value of biaxial stress is found to be an order of magnitude smaller while the strains are two-orders of magnitude lower than the lattice misfits between 3C-SiC and Si bulk crystals. Bruggeman's effective medium theory is utilized to explain the observed atypical IRR spectra in 3C-SiC/Si (001) epifilms. High density intrinsic defects present in films and/or epilayer/substrate interface are likely to be responsible for (a) releasing misfit stress/strains, (b) triggering atypical features in IRR spectra, and (c) affecting observed local structural traits in SR-EXAFS.