AMORPHOUS TERNARY TA-SI-N DIFFUSION BARRIER BETWEEN SI AND AU

Reactively sputtered Ta-Si-N films are investigated as diffusion barriers between silicon and Au layers. Analyses by backscattering spectrometry and electrical measurements on shallow n+p junction diodes reveal that an-amorphous Ta36Si14N50 thin film approximately 110 nm thick very effectively preserves the integrity of the metallization on shallow junctions up to 30 min annealing at 750-degrees-C in vacuum. (The Au-Si eutectic is at 360-degrees-C). At that temperature small openings appear in the Au overlayer which do not, however, affect the electrical characteristics of the diodes. Destructive metallurgical interactions occur at higher temperatures causing a shorting of the shallow junction diodes.