Iron impurity state in vapor and solid phases during the epitaxy of gallium arsenide in the Ga-AsCl/sub 3/-H/sub 2/ system

In this work, the doping of epitaxial gallium arsenide layers by iron is investigated in the chloride vapor-transport system. The Feimpurity states in the vapor and solid phases are analyzed, and the effect of iron on the structural perfection as well as the electrophysical properties of the layer is studied. Epitaxial layers of GaAs were grown in the Ga-AsCl/sub 3/-H/sub 2/ system. It is shown that the solubility limit is 2.10/sup 17/ at/cm/sup 3/ under epitaxial conditions. From a comparison of the electrical measurements and mass-spectrometric data on the layers it follows that a part of the Fe impurity enters into the layer in an electrically inactive form. The precipitates of a second phase are detected by x-ray topography of the iron-doped GaAs layers.