Bj. Mrstik et al., A study of the radiation sensitivity of non-crystalline SiO2 films using spectroscopic ellipsometry, IEEE NUCL S, 45(6), 1998, pp. 2450-2457
Dry thermal oxides were grown on Si substrates at temperatures from 900 deg
rees C to 1200 degrees C. Portions of these oxides were then annealed for 1
0 min at temperatures from 900 degrees C to 1125 degrees C. Spectroscopic e
llipsometry was used to determine the density of these oxides, and to look
for the existence of an interfacial layer. It was found that the oxide dens
ity depends on both the growth temperature and the anneal temperature. No e
vidence was found of an interfacial layer. The oxides were then irradiated
with x-rays, and the radiation-induced shift of the flatband voltage was de
termined. It was found that the radiation response was related to the oxide
density determined by spectroscopic ellipsometry. These results suggest th
at the macroscopic structure of the oxide influences the extent of charge t
rapping.