Interfacial crystallization and amorphization of silicon under ion bombardment

At temperatures well below those for which thermally activated solid phase crystallization of amorphous silicon can be observed, crystallization can be stimulated by ion bombardment. Atomic displacements produced by the bombarding ions allow rearrangement of the tangled amorphous bonding. In addition, for each ion species, energy and flux there is a temperature below which the amorphous to crystalline transformation is reversed; the amorphous phase grows into the crystalline phase by linear motion of the interface. The evidence for these phenomena is discussed together with a preliminary model for the reversible interface motion.