THERMAL AND ION-BEAM DIFFUSION CONSTANTS OF SB IMPURITY IMPLANTED INTO [100]NI SINGLE-CRYSTAL

In previous investigations (A. Belattar et al., Nucl. Instr. and Meth. B 88 (1994) 394; B 93 (1994) 261) the anneaIing of the surface amorph ous layer produced in [100] Ni crystal by implantation of 40 keV Sb2to a fluence of 10(17) ions cm(-2) was observed to occur in two distin ct stages irrespective of whether the anneal process was due to an iso chronal anneal in the temperature range 250 to 1100 degrees C or wheth er the process involved the high energy irradiation with 1.5 MeV Ar or Xe ions at a constant temperature of 350 degrees C. In this study the diffusion of the Sb was monitored by observing the Sb profile using t he Rutherford backscattering technique. A computer fitting procedure w as adopted to quantitatively determine the standard deviation of the w idth of the Sb profile (Omega), the results of which showed that this is a good parameter for monitoring the various diffusion processes. Th e results of the analysis show that in the case of the first anneal st age the diffusion is relatively slow, but that there is evidence that some form of segregation of the Sb impurity occurs; this is most prono unced during a prolonged isothermal anneal carried out at 350 degrees C. The second rapid anneal stage is accompanied by an equally rapid di ffusion of the Sb impurities. In the case of the isochronal anneal, th e activation energy for the diffusion process was measured to be 2.0 e V, which is not incompatible with a vacancy diffusion mechanism. In th e case of the ion beam annealing processes, the monitoring of Omega cl early showed a considerable enhancement of the main diffusion process of the Sb impurity which is directly related to the vacancies produced by the incident high energy irradiation.