Assessing Biaxial Stress and Strain in 3C-SiC/Si (001) by Raman Scattering SpectroscopyTalwar DN1*, Wan L2, Tin CC3 and Feng ZC2
- *Corresponding Author:
- Talwar DN
Department of Physics
Indiana University of Pennsylvania
975 Oakland Avenue, 56 Weyandt Hall
Indiana, Pennsylvania 15705- 1087, USA
E-mail: [email protected]
Received Date: January 28, 2017; Accepted Date: February 16, 2017; Published Date: February 26, 2017
Citation: Talwar DN, Wan L, Tin CC, Feng ZC (2017) Assessing Biaxial Stress and Strain in 3C-SiC/Si (001) by Raman Scattering Spectroscopy. J Material Sci Eng 6:324. doi: 10.4172/2169-0022.1000324
Copyright: © 2017 Talwar DN, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Highly strained 3C-SiC/Si (001) epilayers of different thicknesses (0.1 μm-12.4 μm) prepared in a vertical reactor configuration by chemical vapor deposition (V-CVD) method were examined using Raman scattering spectroscopy (RSS). In the near backscattering geometry, our RSS results for “as-grown” epilayers revealed TO- and LO-phonon bands shifting towards lower frequencies by approximately ~2 cm-1 with respect to the “free-standing” films. Raman scattering data of optical phonons are carefully analyzed by using an elastic deformation theory with inputs of hydrostatic-stress coefficients from a realistic lattice dynamical approach that helped assess biaxial stress, inplane tensile- and normal compressive-strain, respectively. In each sample, the estimated value of strain is found at least two order of magnitude smaller than the one expected from lattice mismatch between the epilayer and substrate. This result has provided a strong corroboration to our recent average-t-matrix Green’s function theory of impurity vibrational modes – indicating that the high density of intrinsic defects at the 3C-SiC/Si interface are possily responsible for releasing the misfit stresses and strains. Unlike others, our RSS study in “as-grown” 3C-SiC/Si (001) has reiterated the fact that for ultrathin epilayers (d<0.4 μm) the optical modes of 3C-SiC are markedly indistinctive. The mechanism responsible for this behavior is identified and discussed. PACS: 78.20.-e 63.20.Pw 63.20.D.