Heteroepitaxial Nd0.32Y0.68Si1.7 layers with good crystalline quality (chi(min) of Nd and Y is 3.5% and 4.3%, respectively) have been prepared by high dose 65 keV Y and 80 keV Nd implantation into a Si(111) substrate using channeled ion beam synthesis. Although the disilicide of Nd only exists in a tetragonal or an orthorhombic phase which cannot be grown epitaxially on a Si(111) substrate, our results show that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. Rutherford backscattering/channeling and x-ray diffraction studies reveal that the lattice parameters of the Nd0.32Y0.68Si1.7 epilayer are a(epi) = 0.3915 nm and c(epi) = 0.4152 nm and that the epilayer is stable up to 950 degrees C. Annealing at 1000 degrees C results in partial transformation into other unidentified phases. (C) 1998 American Institute of Physics. [S0003-6951(98)00619-6].