Amorphous Ta-Si-N thin-film alloys as diffusion barriers in AI/Si metallizations

Amorphous Ta–Si–N thin films of a wide range of compositions were prepared by rf reactive sputtering of a Ta₅Si₃ target in a N₂/Ar plasma. The relationship between films’ composition and resistivity is reported. All obtained films were tested as diffusion barriers between Al and Si. Backscattering spectrometry combined with cross‐sectional transmission electron microscopy were used to determine the barrier effectiveness. It was found that aluminum can be melted on top of the Si/Ta–Si–N structure (675 °C for 30 min) without any evidence of metallurgical interactions between the layers.