Characterization of Reactively Sputtered Ti-Si-N Films
It has become widely accepted that aluminum will be replaced by copper in future silicon integrated circuit devices because copper has a lower resistivity and higher resistance to electromigration than aluminum. However, because copper and silicon are highly reactive to each other, a diffusion barrier is necessary between them. Among the many barrier materials which have been investigated, ternary amorphous metallic materials such as Ta-Si-N and Ti-Si-N have shown superior performance in limiting the diffusion of Cu metallization. Meanwhile, because of the suppression of dislocation activity in Ti-Si-N films, those films also have the potential to be effect in applications requiring a hard coating. Presented in this study are Ti-Si-N films with thickness from 100nm to 200nm that were reactively deposited by R.F. magnetron sputtering using various N2/(Ar+N2) partial pressure ratios. The composition, resistivity, microstructure, microhardness, and chemical bonding state of the sputtered films were studied. The ability to do copper plating on those films has also been investigated. All Ti-Si-N films were found to be amorphous. The chemical bonding state of the films played a critical role in the resistivity, microstructure and microhardness of the films. With increasing Si3N4 bonding content, the film resistivity increased. An increase in the amount of Si3N4 bonding in the films causes an increase in the film microhardness until a maximum hardness value was attained, after which the film microhardness decreased with increasing Si3N4 bonding content. However, the Si3N4 bonding content in the films could be controlled by adjusting N2 partial pressure in the sputtering gas
B. Y. Johnson et al., "Characterization of Reactively Sputtered Ti-Si-N Films," Surface Engineering: Proceedings of the 4th International Surface Engineering Congress, ASM International, Jan 2006.
Materials Science and Engineering
Keywords and Phrases
Diffusion Barriers; Electrical Resistivity; Electromigration; Integrated Circuits; Microhardness; Titanium Nitrides
Article - Conference proceedings
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