Study of TaSiN thin films for use as barrier layer in copper metallizations
This work focuses on the deposition process, microanalytical characterization and barrier behaviour of 10100-nm thick sputtered TaSi and TaSiN films. Pure TaSi films were found to be already nanocrystalline. The addition of N2 leads to a further grain fining resulting in amorphous films with excellent thermal stability. According to microanalytical investigations, TaSi barriers between Cu and Si with a thickness of only 10 nm are not stable at 600C. Copper silicides are formed due to intensive Cu diffusion throughout the barrier. In contrast, 10-nm thick nitrogen-rich TaSiN barriers remain thermally stable during annealing at 600C and protect the Si wafer from Cu indiffusion.
tasi tasin diffusion barrier nanocrystalline materials amorphous materials cu metallization