Silicon homoepitaxy with ion sputtering. II. Formation of defects

Defects of homoepitaxial Si films were investigated by electron microscopy. It is shown that the defects occur on surface inhomogeneities, i.e. on pits with the developed surface morphology. At small film thicknesses the main defects are coherent inclusions which are transformed to incoherent particles of SiC with thickness increase. Microphotography analysis and estimations of power for the possible carbon sources show that the growth of SiC particles is limited by surface processes. From elastic deformation of coherent inclusions the Vegard constant is estimated for interstitial solution of carbon into silicon. A comparison of the substitutional solution and the interstitial one shows that the interstitional solution is favoured in an early stage of SiC nucleation.