The study addresses the stability of point defects in SrTiO3 during thin film

processing using electron paramagnetic resonance spectroscopy. In particular, the

intensity of the Fe3+VO electron paramagnetic resonance signal was monitored after

various steps during the growth of SrTiO3 films on SrTiO3 substrates. Controlled

O2 and vacuum heat treatments were also performed to clarify the fundamental mechanisms responsible for the effects of different processing steps. Comparison

of results from film fabrication with those obtained during exposure to the control

ambient showed that the presence of oxygen in the pre-treatment growth

atmosphere decreased the amount of the Fe3+VO complex, but exposure to the low

pressure environment of the growth chamber returned the signal to the original

intensity. These results were consistent with accepted theories of oxygen vacancy

diffusion. However, an unexpected decrease in the oxygen vacancy related signal

was also observed during vacuum treatment of an as-received sample. Furthermore,

the decrease occurred over the same temperature range as seen for an O2 anneal.

The difference between the O2 and vacuum treatments was revealed in postannealing

photo-induced electron paramagnetic resonance and resistivity

measurements, which indicate that vacancy related centers change charge state

during the O2 anneal and were not removed by oxygen. The effect of the vacuum

treatment, though different from that of oxygen, was not yet clear as no charge

state changes were induced after exposure to visible or ultraviolet radiation, but the

conductivity of the samples changed.

An Annealing Study of an Oxygen Vacancy Related Defect in SrTiO3 Substrates.

M.E.Zvanut, S.Jeddy, E.Towett, G.M.Janowski, C.Brooks, D.Schlom: Journal of

Applied Physics, 2008, 104[6], 064122