Defects at the interface of ultra-thin VUV-grown oxide on Si studied by electron spin resonance

Ultra-thin ( 2 nm) Si-oxide ®lms, grown by vacuum ultraviolet (VUV) enhanced oxidation of Si at 300 K, were studied using electron spin resonance monitoring of Si dangling bond-type interface defects. As a major impact of VUV photons, large densities (up to 9 1012 cmÿ2) of Pb and Pb0 centers (interfacial (Si3BSi )) are observed in VUV-grown (1 1 1) and (1 0 0) Si/SiO2, respectively. Their features indicate that, as compared to standard thermal Si/SiO2, the VUV Si/SiO2 interface is under much enhanced stress. No Pb1 defects are observed in VUV (1 0 0) Si/SiO2, ascribed to lack of high temperature oxide relaxation. This may appear pertinent as to the understanding of the defectʹs speci®c role in the interface structure. Microscopic understanding is provided for the known inferior electrical interface quality threatening low thermal budget oxide fabrication. # 2000 Elsevier Science B.V. All rights reserved