A general point defect model is proposed to explain the behavior of arsenic precipitation in low-temperature grown III-V arsenides. From transmission electron microscopic studies on p, i, and n-doped LT-GaAs, the density of As precipitates was found to be the lowest in the n-type material and the highest in the p-type one. In an n-i-p structure, a wider depletion zone of As precipitate exists in the n-i interface than the i-p interface. It is also found that for a heterostructure containing materials with different bond strengths, As precipitates tend to condense in the material with lower bond strength. This is due to the higher vacancy concentration in the material with lower bond strength. These results imply that materials with higher bond strength, such as AlGaAs and AlAs, are As diffusion barriers in heterostructures. Line defects are also shown to facilitate As precipitation because they provide extra vacancies.
|Number of pages||5|
|Journal||Journal of Crystal Growth|
|State||Published - May 1999|
|Event||Proceedings of the 1998 10th International Conference on Molecular Beam Epitaxy (MBE-X) - Cannes|
Duration: 31 Aug 1998 → 4 Sep 1998