Anomalous diffusion behavior of Mg in GaAs

Abstract

This experiment was undertaken to demonstrate that the anomalous diffusion behavior reported of Al in the alloy system (AlGa)As is not unique. The interdiffusion of Al and Ga across the buried heterojunctions between the AlAs and GaAs layers of a superlattice structure has been shown to be slow, whereas very much faster diffusion has been observed into the free surface of a GaAs wafer exposed to a saturated solution containing these two elements and Al. In this letter it is shown that Mg exhibits similar behavior and, further, a consequence is that when Mg is used to dope GaAs layers grown by liquid phase epitaxy the dopant penetrates to a significant depth in the underlying solid.