POINT-DEFECT GENERATION IN SIO2 BY INTERACTION WITH SIO AT ELEVATED-TEMPERATURES

The interaction of fused silica (SiO2) with gaseous SiO during anneali ng at similar to 1140 degrees C has been studied by electron spin reso nance (ESR). In contrast with annealing in vacuum, this results in the generation of an isotropic defect in SiO2 of g = 2.0028 and peak-to-p eak width 3.6-6 G. These spectroscopic properties are similar to those of the signal found generated in the oxide layer of standard thermal Si/SiO2 structures upon postoxidation annealing in vacuum at greater t han or equal to 960 degrees C, assigned to S centers, tentatively ascr ibed previously to E'-like defects of the type O2Si=Si . or OSi2=Si .. An attendant observation is enhanced sensitivity of the SiO2 network to photogeneration (VUV) of E'(gamma) defects (O vacancy center O-3=Si .). The results suggest that interaction of interface generated SiO w ith the SiO2 network may explain the degradation of the thermal Si/SiO 2 structure during postoxidation annealing in vacuum.