Thin amorphous GaAs layers on (100)‐oriented substrates, generated by Si+ion bombardment at 77 K, have been observed to recrystallize epitaxially during 1.5‐MeV Ne+bombardment in the temperature range 75–135 °C. Crystallization proceeds linearly with increasing ion fluence, except in the near‐surface region, and the process is characterized by an activation energy of 0.16 eV, which is an order of magnitude smaller than that obtained for conventional thermal annealing at much higher temperatures.