Strain in GaP Films Heteroepitaxially Grown on Si
Kazuhiro NAKAMURA, Takashi FUYUKI and Hiroyuki MATSUNAMI
Abstract:The residual stress and strain in GaP layers have been studied using X-ray diffraction and Raman scattering techniques. Samples used in this study were GaP films grown on Si substrates by atmospheric-pressure metalorganic chemical vapor deposition (MOCVD), using trimethylgallium (TMGa) and tertiarybutylphosphine (TBP) as source gases. Lattice constants of the epitaxial layer were obtained from the results of X-ray (004) and (115) diffractions. The lattice constant parallel to the growth surface (aa) was longer than the one perpendicular to it (a). The GaP epilayer was two-dimensionally strained in the growth plane. This is explained by the difference in thermal expansion coefficients. The degree of strain was also verified by the results of Raman scattering measurements. Key Words:GaP, Si, heteroepitaxy, strain, Raman spectroscopy, X-ray diffraction