A B-buried layer with a dose of 1014/cm2 was introduced into p-doped Si at a depth of 2.2µm in order to enhance Cu diffusion via its inherent gettering effect. The Cu was then introduced into Si either via a low-energy implantation followed by thermal annealing, or through the thermal drive in of physical vapor deposited Cu film. Secondary ion mass spectrometry depth profiling of both annealed samples later indicated that while substantial amounts of Cu were gettered by the B layer in the former sample, no Cu was gettered by the B-buried layer in the latter sample. Further analysis with an X-ray diffraction technique showed that Cu3Si was formed in the latter sample. It was thus surmised that the formation of this silicide layer impeded the diffusion of Cu towards the B-buried layer. This work investigates the cause of CuSix formation and the underlying reasons for the lower mobility of Cu in physical vapor deposited Cu film samples.

Study of Copper Silicide Retardation Effects on Copper Diffusion in Silicon. C.S.Lee, H.Gong, R.Liu, A.T.S.Wee, C.L.Cha, A.See, L.Chan: Journal of Applied Physics, 2001, 90[8], 3822-4