A novel contact-hole filling technology with selective CVD-W for shallow junctions

Selective deposition of CVD-tungsten(W) is becoming an effective technology for contact-hole filling in sub-micron multilayer inter-connection, which realises, low contact resistance and barrier-metal effect. The contacts for shallow junctions, however, suffer from serious degradation of breakdown voltage and increase of leakage-current caused by consumption of diffused layer by the reaction of WFs with Si and encroachment of W along the SiO₂/Si interface in contact hole. These problems are becoming fatal in sub-micron interconnection for scaled-devices with shallow junctions.