Ion-implanted, electron-beam annealed TiN films as diffusion barriers for Al on Si shallow junctions

Abstract

TiN films are prepared by N+2 implantation onto evaporated Ti films. By properly selecting the Ti thickness, implantation energy and annealing process, a TiSi2/TiN structure can be formed. In particular, in this work a postimplant rapid isothermal annealing is carried out at 800 °C for 30 s by using an electron beam. The effectiveness of these TiN films as a diffusion barrier is then evaluated when put in contact with a thick Al overlayer. Both the TiN/Al and TiSi2/TiN/Al contact structures are tested, after thermal treatments up to 600 °C, on shallow junction diodes and four terminal resistor test patterns for contact resistance measurements. The electrical performances of the TiSi2/TiN/Al contact system are found to be good, although the degradation resistance is slightly worse than the one observed on similar structures annealed in a vacuum furnace after the nitrogen implantation.