Influence of hydrogen on room temperature recrystallisation of electrodeposited Cu films: thermal desorption spectroscopy

Abstract

The mechanism of recrystallisation observed at room temperature in electrodeposited Cu films has been examined in light of the enhancement of metal atom diffusion by hydrogen induced superabundant vacancies. Thermal desorption spectroscopy revealed that Cu films electrodeposited from acid sulphate bath containing some specific additives showed a pronounced peak, which was ascribed to the break-up of vacancy–hydrogen clusters. The amount of desorbed hydrogen was comparable to that of vacancy type clusters estimated in previous positron annihilation experiments. The grain size of Cu films increased as hydrogen desorption proceeded. Such grain growths were not observed in the films deposited from the baths without additives. These results indicate that the room temperature recrystallisation of electrodeposited Cu films is caused by hydrogen induced superabundant vacancies.

Keywords:

• Electrodeposited Cu film
• Room temperature recrystallisation
• Hydrogen induced superabundant vacancies

The present work was partly supported by a Grant-in-Aid for Scientific Research (c) (grant no. 21560692) from JSPS.