低速陽電子ビームを用いたhigh-κ 膜の空隙評価

Positron annihilation is an established technique for investigating defects in solids. Using this technique, thin Hf0.3Al0.7Ox films fabricated by an atomic-layer-deposition technique were characterized. It was found that positrons in the HfAlOx films annihilate from the trapped state by open spaces that exist intrinsically in their amorphous structure. The line-shape parameter S and the positron lifetime corresponding to the HfAlOx films decreased with increasing oxygen content in the annealing atmosphere. This fact was attributed to the shrinkage of the open spaces due to the change in the matrix structure of amorphous HfAlOx. A clear correlation between the mean size of the open spaces in HfAlOx and the suppression of transient leak current was observed.