The structural degradation of thermal SiO2 on (100)Si under isochronal vacuum annealing (950 to 1250C) was monitored by electron spin resonance in terms of point defect creation, including Eγ’, Eδ’, EX and the elusive predominant degradation-center S. Depth profiling after heating at 1200C showed that the S centers mainly resided near to the oxide borders, generally in anticorrelation with the Eγ’ distribution. The resulting anisotropic demagnetization effect had enabled inference of the S center susceptibility. As to the nature of the S center, an observed weak hyperfine structure may comply with the S center being of the type SinO3–n≡Si• either the single n = 1 or a mixture of the n = 1,2 variants.

Characterization of S Centers Generated by Thermal Degradation in SiO2 on (100)Si. A.Stesmans, B.Nouwen