Elaboration of thin chromium silicide layers on P+ implanted silicon

The aim of the present work is to investigate the mechanism of growth of chromium silicides versus several parameters. The samples are constituted of a thin chromium layer (∼80 nm) which is deposited under vacuum by electron beam evaporation/condensation onto P+ implanted Si(1 0 0) and Si(1 1 1) substrates. Phosphorus ion implantation, with a dose of 5x1014 or 5x1015 P+ cm-2, is performed at an energy of 40 keV. The samples are thermally annealed at 723-823 K (450-550 deg. C) for various periods of time. The analysis is carried out by means of X-ray diffraction and H+ Rutherford backscattering spectrometry (RBS) techniques. The RUMP 3.30 software is used to simulate RBS spectra. It is shown that, after annealing treatment, the CrSi2 silicide is formed at Cr/Si(1 0 0) and Cr/Si(1 1 1) interfaces. For one temperature and time of annealing, the thickness of the chromium disilicide is lower for the high phosphorus dose (i.e., 5x1015 P+ cm-2) than for the low dose (i.e., 5x1014P+ cm-2). In other words, the presence of phosphorus in silicon substrates delays the formation of the CrSi2 phase but does not inhibit it. Finally, it is established that the growth of CrSi2 compound is more rapid on silicon substrates with <1 1 1> orientation than on the <1 0 0> orientation, which is not in agreement with the non-implanted specimens case