Controlling nickel silicide phase formation by Si implantation damage

Abstract

In the context of fabrication process of contacts in CMOS integrated circuits, we studied the effect of implantation-induced damage on the Ni silicide phase formation sequence. The device layers of Silicon-on-insulator samples were implanted with 30 or 60keV Si ions at several fluences up to amorphization. Next, 10 or 30nm Ni layers were deposited. The monitoring of annealing treatments was achieved with time-resolved X-ray diffraction (XRD) technique. Rutherford Backscattering Spectrometry and pole figure XRD were also used to characterize some intermediate phase formations. We show the existence of an implantation threshold (1ions/nm2) from where the silicidation behaviour changes significantly, the formation temperature of the disilicide namely shifting abruptly from 800 to 450°C. It is also found that the monosilicide formation onset temperature for the thinner Ni deposits increases linearly by about 30°C with the amount of damage.