Paramagnetic interfacial Pb defects (SiSi3) in (111)Si/SiO2 samples were studied at temperatures ranging from 480 to 1135C. As well as confirming the dissociation (above about 460C) of pre-existing HPb, electron spin resonance data revealed the existence of irreversible Pb creation at temperatures above about 640C. The Pb density increased monotonically with temperature and showed no sign of saturating at 1135C, where the Pb density was 1.3 x 1013/cm2. It was deduced that the critical creation step was post-oxidation thermal cycling in an O-free ambient.

A.Stesmans, V.V.Afanasev: Journal of Physics - Condensed Matter, 1996, 8[36], L505-9