Characterization of Tensile Strained Si1-yCy Alloy Grown by Photo- and Plasma Chemical Vapor Deposition at Very Low Temperature

Abstract

Epitaxial growth of Si1-yCy films on Si(001) by photochemical vapor deposition (photo-CVD) and plasma-enhanced chemical vapor deposition (plasma-CVD) is reported. We obtained the epitaxial Si films by the addition of C2H2 or CH4 to SiH4 and H2 gases using both methods at a very low substrate temperature of 200°C. Hydrogen incorporation in the epitaxial films and lattice expansion by H atoms were observed. The H atoms in the film desorbed by thermal annealing in N2 atmosphere. The C local vibration mode in the Si network (607 cm-1) was detected in the films annealed at temperatures higher than 600°C. X-ray diffraction peak of the Si1-yCy layer shifted to a higher angle by the annealing. The X-ray reciprocal lattice space mapping indicated pseudomorphic growth of Si1-yCy alloys. Thus, the tensile strained Si1-yCy alloy with a high substitutional C content of 2.7% was successfully obtained.