An investigation was made of the roles played by damage production and annealing in determining Fe redistribution when implanting the latter at MeV-energies into n-type material. Here, 2MeV Fe-ion implantation was performed on (100) substrates of both undoped and Sn-doped (1.5 x 1018/cm3) material. The implantation was performed at room temperature or 200C, to doses which ranged from 1013 to 1.2 x 1015/cm2. Double-implantation was also performed, in which Fe and P were co-implanted in order to investigate the effect of P-induced damage upon Fe redistribution and accumulation. Annealing was performed at temperatures ranging from 650 to 800C, under flowing phosphine. Rutherford back-scattering spectrometry channelling and transmission electron microscopy were used to characterize damage before and after annealing. The Fe depth profiles were measured by using secondary-ion mass spectrometry. A clear correlation was found between the positions of Fe accumulation peaks and those of secondary defects which formed in 25C-implanted samples during annealing. In particular, it was shown that end-of-range dislocation loops and interfaces between damaged and undamaged crystalline regions acted as gettering sites for Fe atoms. The accumulation process was controlled by Fe diffusion, and was greatly enhanced by the presence of mobile point defects which were related to the implantation damage. On the other hand, it was shown that Sn doping had a marked retarding effect upon Fe diffusion. It was demonstrated that a sharp reduction in damage production, which was related to dynamic annealing in 200C-implantation, could be used to reduce or avoid Fe redistribution and accumulation; thus leading to fairly stable implantation profiles at high annealing temperatures and long annealing times.

Interaction between Fe, dopants and secondary defects in MeV Fe-ion implanted InP A.Gasparotto, A.Carnera, C.Frigeri, F.Priolo, B.Fraboni, A.Camporese, G.Rossetto: Journal of Applied Physics, 1999, 85[2], 753-60