Synthesis and characterization of compositionally graded Si1−xGex layers on Si substrate

Abstract

Thin film of silicon germanium (Si1−xGex) with tailored composition was grown on Si(100) substrate at 650°C in an ultrahigh vacuum molecular beam epitaxy system. The quality of the film was investigated by Rutherford backscattering spectrometry (RBS) in random and channeling geometries, glancing angle X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The nominal x-value ranged from 0 to 0.14. RBS/channeling measurements indicate that the strain associated with lattice mismatch is compressive in the film. The film shows island growth, which is driven by interface misfit dislocation.