Formation of TiSi2 thin films from chemical vapor deposition using TiI4

Abstract

The formation of TiSi2 films by chemical vapor deposition was investigated for the application as a contact plug material because of its low resistivity, low contact resistance with n(+) and p(+) Si, and good chemical stability with Si. TiI4 and SiH4 were used as source gases. TiSi2 thin films with C49 phase were formed at 650 degrees C on Si (100) wafer, while a Ti5Si3 phase was formed at 650 degrees C on SiO2 substrate. The resistivity of the C49 phase films was 210 mu Omega-cm. The C49 phase was completely transformed into a C54 phase above 800 degrees C annealing in an NZ atmosphere and the resistivity reduced to 34 mu Omega-cm. We were able ts deposit TiSi2 films at lower temperature using TiI4 precursor, compared to TiCl4 precursor. The Cl and HCl byproducts that originated from TiCl4 can be excluded using TiI4 precursor.