Surface Defect Formation in Epitaxial Si Grown on Boron-Doped Substrates by Ultrahigh Vacuum Chemical Vapor Deposition

We have investigated the formation mechanism of surface defects in a Si epitaxial layer grown on BF2+-implanted Si(100) substrates by ultrahigh vacuum chemical vapor deposition. The density of surface defects increases linearly with the BF2+ dose. It is found that surface defects are generated at the interface, although neither stacking faults nor dislocations are formed in the epitaxial layer. X-ray photoelectron spectroscopy measurements revealed that surface segregation of boron occurs. We propose a model of the defect formation in which inhomogeneous distribution of segregated boron across the substrate surface causes the difference in the epitaxial growth rate between high and low boron concentration regions.