Thermal stability of a HfO2∕SiO2 interface

Abstract

Using high-angle annular-dark-field scanning transmission electron microscopy, we showed how annealing at 1000 ° C changes the chemical composition distribution at a Hf O 2 ∕ Si O 2 interface. The observed change in the distribution was analyzed in terms of Hf diffusion in Si O 2 ; the diffusion coefficient was estimated to be 2.5 × 10 − 18 cm 2 ∕ s . This diffusion coefficient indicates that the high-temperature annealing, such as that in the conventional dopant activation process used to fabricate semiconductor devices, barely changes the chemical composition distribution at the Hf O 2 ∕ Si O 2 interface.