166Er atoms were implanted with an energy of 70 to 90 keV and doses of 0.8 to 2.0×1017/cm2into Si(111) substrates at temperatures ranging from 450 to 530 °C. We found that using conventional nonchanneled implantation at energies of ∼90 keV, it is impossible to form a continuous ErSi1.7layer. At best, after annealing, a discontinuous ErSi1.7layer with poor crystalline quality (&khgr;min=40%) is obtained. On the contrary, using channeled implantation, a continuous epitaxial ErSi1.7layer with very good crystalline quality can be formed; a lowest &khgr;minvalue of 1.5% for a surface ErSi1.7layer has been obtained. The origin of this different behavior is explained. Our results show that for synthesizing continuous ErSi1.7layers with good quality using ion beam synthesis at energies around 90 keV, channeled implantation is indispensable. ©1995 American Institute of Physics.