The possibility of amorphization of a Si crystal bombarded at room temperature with He ions was studied by monitoring structural changes in the target crystal by means of transmission electron microscopy. Thin free-standing Si(100) plates were irradiated from the plane edge ({011} face) with 17keV He+ ions in a dose range from 3 x 1016 to 3 x 1017/cm2. It was established that amorphization of the Si crystal took place at a total fluence which exceeded 1017/cm2; provided that the ratio of the point defect production rate to the rate of He introduction into Si exceeded 90 displacements per He atom.

Helium Ion Bombardment Induced Amorphization of Silicon Crystals. V.F.Reutov, A.S.Sokhatski: Technical Physics Letters, 2002, 28[7], 615-7