Oxygen diffusion and reactions in Hf-based dielectrics

Oxygen transport in and reactions with thin hafnium oxide and hafnium silicate films have been investigated using medium energy ion scattering in combination with O218 isotopic tracing methods. Postgrowth oxidation of Hf-based films in an O218 atmosphere at 490–950°C results in O exchange in the film. The exchange rate is faster for pure hafnium oxides than for silicates. The amount of exchanged oxygen increases with temperature and is suppressed by the SiO2 component. Films annealed prior to oxygen isotope exposure show complex incorporation behavior, which may be attributed to grain boundary defects, and SiO2 phase segregation.