Magnesium-doped GaAs and Al<i>x</i> Ga1−<i>x</i> As by molecular beam epitaxy

Abstract

Molecular beam epitaxy (MBE) of Mg-doped GaAs and AlxGa1−xAs layers was studied in situ by high-energy electron diffraction and Auger spectrometry. The analysis of the incorporation of Mg into the layers was studied with a Cameca (IMS 300) ion-sputtering mass spectrometer and by Hall-effect determination. It has been demonstrated that the sticking coefficient of Mg increases very rapidly (almost 3 orders of magnitude) under the specific conditions of this experiment when x increases from zero to 0.2, and that controlled p-type doping of GaAs and AlxGa1−xAs with Mg during MBE is possible. A new surface structure (001)−2×2-Mg is observed when a Mg beam impinges on a GaAs or AlxGa1−xAs surface.