Quantitative Evaluation of Strain in Epitaxial 2H-AlN Layers
To improve the quality of AlN layer deposit on SiC/Si, different Ge amounts (0.25, 0.5, 1, 2ML) were deposited before the carbonization process at the silicon substrate in order to reduce the lattice parameters mismatch between Si and SiC grown layers. The residual stress of the hexagonal AlN layers derives from the phonon frequency shifts of the E1(TO) phonon mode. The crystalline quality of the AlN layer is correlated to and investigated by the full width of the half maximum (FWHM) and the intensity of E1(TO) mode of the 2H-AlN. Best crystalline quality and lower stress value are found in the case where 1ML of Ge amount is predeposited. The E1(TO) mode phonon frequency shifts-down by 3 cm-1/GPa with respect to an unstrained layer.
Maher Soueidan, Mohamad Roumié and Pierre Masri
R. Nader and J. Pezoldt, "Quantitative Evaluation of Strain in Epitaxial 2H-AlN Layers", Advanced Materials Research, Vol. 324, pp. 213-216, 2011