New Ar-plasma cleaning process for reduction of Al/TiSi2 contact resistance

RF-Ar-plasma cleaning lowers Al/TiSi2 contact resistivity by 70% in compari son to conventional buffered-HF (BHF) cleaning. This improvement is due to effective removal of contaminants at the bottom of contact holes. Applicati on of the Ar-plasma treatment to the Si surface before silicidation leads t o a decrease in contact resistance down to 25 Omega for 0.3-mu m-diameter c ontact holes. The decrease is believed to be due to the fact that the effec tive barrier height between TiSi2 and n(+)-Si is reduced by defects induced by Ar cleaning.