High thermal stability and low electrical resistivity carbon-containing Cu film on barrierless Si

Abstract

Interfacial structures and electrical resistivities of a carbon-doped Cu film at different annealing temperatures and times were investigated. The film was prepared by magnetron sputtering on barrierless silicon. After annealing, grain growth was distinctly hindered and a carbon-containing nanometer thick passive amorphous layer was formed at the film/substrate interface. The film had a resistivity of about 2.7 μΩ cm after annealing at 400 °C for 1 h and maintained a low resistivity of 3.8 μΩ cm even after 9 h annealing at 400 °C. The low electrical resistivity in combination with the high thermal stability makes carbon doping a promising technique for future Cu interconnects on barrierless Si.