Barrier Properties of Tasi2 in Contact With Al-Metallization

Abstract

ABSTRACTThe reaction between cosputtered amorphous and polycrystalline tantalum silicide with Al-Si-metallization was investigated by means of Schottky and ohmic contacts on Si. Diffusson of Al and Si across the silicide was impeded up to 475 °C, as long as the silicide films contained excess Ta with respect to the TaSi2 stoichiometry. The results show that Al-Si with a thin Ta-rich tantalum silicide underlayer provides a VLSI-metallization with considerably reduced contact resistance, particularly for small contacts, and low Schottky barrier to n-Si without significant Si consumption from the substrate