Films of Co with a thickness of about 120nm were deposited onto Si(100) substrates and were then annealed (400-700C, 2h). This resulted in the formation of over-layers that consisted of Co (400C), CoSi (500C) or CoSi2 (600 or 700C). The various phases were easily distinguished by means of Rutherford back-scattering and positron annihilation spectroscopy. The values of the Doppler broadening S-parameter for CoSi and CoSi2 (formed at 700C) were equal to the stoichiometrically weighted averages of the S-parameters of the constituents. It was therefore proposed that positron trapping sites which had previously been detected in CoSi2 by using re-emitted positron spectroscopy were probably grain boundaries and dislocations. Open-volume defects (perhaps voids) were detected, via positron annihilation spectroscopy, in CoSi2 that formed at 600C.

A.P.Knights, M.W.G.Ponjée, P.J.Simpson, M.Zinke-Allmang, G.R.Carlow: Semiconductor Science and Technology, 1997, 12[2], 173-8