The effect of dislocation reduction in HgCdTe epilayers which had been grown onto GaAs substrates by means of molecular beam epitaxy was studied by using thermal annealing in a Hg atmosphere. It was found that dislocation movement in the epilayer was activated when the annealing temperature was greater than 250C. This behavior was analyzed by using a simple model that had been applied to dislocation reduction in GaAs layers on Si. The model was based upon dislocation movement under thermal stresses. On the basis of the experimental and the model results, it was suggested that the relationship between dislocation reduction and total annealing time was almost independent of the annealing temperature. The activation energy for dislocation movement in the HgCdTe epilayer was estimated to be about 1eV. This was almost the same as the Hg-vacancy formation energy. It was therefore suggested that dislocations in the epilayer interacted with Hg vacancies, so that dislocation annihilation and re-emission took place.

T.Sasaki, N.Oda: Journal of Applied Physics, 1995, 78[5], 3121-4