Stability of amorphous IrTa diffusion barriers between Cu and Si

Abstract Thin-film amorphous IrTa (aIrTa) has been tested as a diffusion barrier between (100) Si and Cu. Sandwich structures of (100) Si/aIrTa/Cu/aIrTa were found to be stable during annealing in vacuum up to 700°C. At 750°C interdiffusion of Cu and Si took place as observed by Rutherford backscattering spectrometry. Using free-standing aIrTa/Cu/aIrTa samples for transmission electron microscopy, it was determined that the crystallization temperature of thin-film aIr 45 Ta 55 is reduced from 900 to 750°C in the presence of Cu.