TaSix as a Barrier Between Al-Based Metallization and N+- and P+-SI for Reliable VLSI Contacts

Abstract

It is shown, that a thin TaSix layer underneath the Al based metallization considerably improves the contacts from the metallization to shallow diffusion regions in Si. TaSiX with x 2 acts as a barrier against Al and Si diffusion at the contacts and thus impedes Al spiking as well as Si precipitates in the contacts. Furthermore the high current induced Si erosion is reduced by one order of magnitude. The contact resistance to n+-Si is decreased by a factor 3-5. Finally the TaSiX provides a low barrier Schottky diode on lightly doped n-Si and p-Si.