In order to synthesize metastable group-IV binary alloy semiconductor thin films on Si, Si(100) substrates were implanted with 17 keV C ions forSi/ 1−y C y Si and alternatively with 110 keV Sn ions forSi/ 1−z Sn z Si. Subsequent ion-beam-induced epitaxial crystallization (IBIEC) with 400 keV Ar ions at 300–400°C has induced a good epitaxial growth up to the surface both forSi/ 1−y C y Si (y=0.014 at peak concentration) and forSi/ 1−z Sn z Si (z=0.029 at peak concentration). X-ray diffraction measurements have shown a growth ofSi/ 1−y C y Si with smaller tensile strain than forSi/ 1−y C y Si grown by solid phase epitaxial growth (SPEG) up to 650°C. Photoluminescence measurements have revealed properties of defect related to I 1 (Ar) line and G line emissions for IBIEC-grownSi/ 1−y C y Si samples. IBIEC has induced an incomplete crystalline growth and a loss of implanted Sn atoms forSi/ 1−z Sn z Si (z=0.086 at peak concentration).