Paramagnetic point defects were probed by electron spin resonance in stacks of (100) Si with nm-thick SiOx, ZrO2 and Al2O3 layers. After photo-desorption of passivating H (300K, 8.48eV), the Si dangling bond type interface centres Pbo, Pb1 appeared as prominent defects at all (100)Si/dielectric interfaces, with Pbo densities up to about 6 x

1012/cm2. This Pbo, Pb1 fingerprint, generally unique for the thermal (100)Si/SiO2 interface, indicated that, while reassuring for the Si/SiOx/ZrO2 case, the as-deposited (100)Si/Al2O3 interface was basically Si/SiO2-like. As probed by the Pb-type defects, the interfaces were under substantially enhanced stress, characteristic for low-temperature Si/SiO2 growth. Standard quality thermal Si/SiO2 interface properties, as exposed by the Pb-type defects (density about 1012/cm2), may be approached by appropriate mild annealing (about 650C).

Electron Spin Resonance Observation of Si Dangling-Bond-Type Defects at the Interface of (100) Si with Ultrathin Layers of SiOx, Al2O3 and ZrO2. A.Stesmans, V.V.Afanasev: Journal of Physics - Condensed Matter, 2001, 13[28], L673-80