Nickel Precipitation in Silicon: On the Origin of Bright and Dark EBIC Contrast of NiSi2 Precipitates
A. Ihlal, X. Portier, G. Nouet and R. Rizk
Electron beam induced current (EBIC) measurements and transmission electron microscopy (TEM) observations have been performed on = 25 silicon bicrystals precontaminated with nickel before being heat treated at high temperature. The formation of NiSi2 platelets upon quenching lead to a strong and usual minority carriers recombination (dark contrast) and the occurrence of a particular contrast, i.e negative or bright contrast. TEM observations demonstrated the formation of the two well known pure type A and B NiSi2 platelets. The origin of the two kinds of contrast was analysed and discussed in relation with the rectifying behaviour of the buried nickel precipitates and the difference of the potential barrier height of the two type of precipitate (intrinsic origin) and also to the gettering effect of NiSi2 precipitates (extrinsic origin).