Thin germanium–carbon layers deposited directly on silicon for metal–oxide–semiconductor devices

Abstract

We report the growth process and materials characterization of germanium–carbon alloys (Ge1−xCx) deposited directly on Si (1 0 0) substrates by ultra-high-vacuum chemical vapour deposition. The Ge1−xCx films are characterized by transmission electron microscopy, etch-pit density, x-ray diffraction, secondary ion mass spectrometry and electron energy loss spectroscopy. The results show that the films exhibit low threading dislocation densities despite significant strain relaxation. We also present evidence for carbon segregation in the Ge1−xCx and interpret these results as a strain relaxation mechanism.