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Migration kinetics of ion-implanted beryllium in ZnO and GaN

Migration kinetics of ion-implanted beryllium in ZnO and GaN has been studied using the modified radiotracer technique utilizing 7Be tracers. For ZnO the studies were carried out in the temperature range 650–750 °C. Clear Be migration following Arrhenius type behaviour was noted. The process is suggested to be limited due to formation of the BeZnO compound. An activation enthalpy of EA = (2.9 ± 0.3) eV and pre-exponential factor of D0 = 4 × 10−3 m2 s−1 were deduced for Be diffusion in ZnO. In the case of GaN two annealing temperatures were employed, 850 and 950 °C. Distinct trapping of Be in defects induced via implantation was noted. The activation enthalpy for Be diffusion in GaN free of implantation induced defects is estimated to be ∼4 eV in agreement with theoretical predictions presented in the literature.