A composition tunable Si 1-x Ge x alloy has a wide range of applications, including in electronic and photonic devices. We investigate the Al-induced layer exchange (ALILE) growth of amorphous Si 1-x Ge x on an insulator. The ALILE allowed Si 1-x Ge x to be large grained (> 50 lm) and highly (111)-oriented (> 95%) over the whole composition range by controlling the growth temperature (400 C). From a comparison with conventional solid-phase crystallization, we determined that such characteristics of the ALILE arose from the low activation energy of nucleation and the high frequency factor of lateral growth. The Si 1-x Ge x layers were highly p-type doped, whereas the process temperatures were low, thanks to the electrically activated Al atoms with the amount of solid solubility limit. The electrical conductivities approached those of bulk single crystals within one order of magnitude. The resulting Si 1-x Ge x layer on an insulator is useful not only for advanced SiGe-based devices but also for virtual substrates, allowing other materials to be integrated on threedimensional integrated circuits, glass, and even a plastic substrate.