A GAS-RELEASE STUDY OF ANNEALING OF BOMBARDMENT-INDUCED DISORDER (STUDIES ON BOMBARDMENT-INDUCED DISORDER .I.

Many oxides and diamond-type materials become disordered, e.g. amorphous, when bombarded with heavy ions at doses greater than 1014-1016 ions/cm2. Though the most direct evidence for such disorder is probably electron diffraction, much information can also be gained by studying the motion of the ions used to produce the disorder. We have in this way established the following temperatures for disorder annealing (all in °C and for a time scale of 25°C/min): 730 with α-Al2O3, 445 with Cr2O3, 535 with α-Fe2O3, 480 with rutile, 325 with MgO, 285 with NiO, 470 with Ge and 720 with Si. A significant point is that the ratios of the disorder-annealing temperatures to those for atomic-scale cation self-diffusion are similar for most of the materials studied. The temperature widths of the annealing were also measured, and it could be shown that they were, except for MgO and NiO, compatible with single-jump kinetics, namely 45-70°C. It is concluded that the annealing process probably involves the growth of crystalline material towards the bombarded surface, such that the bombarding ions are swept out as the disorder-crystal interface reaches the surface. This model is of interest in implying that the activation enthalpies of the annealing, e.g. 52 ± 3 kcal/mole with rutile, are similar to those for self-diffusion in the disordered phase. © 1969.