Enhancement of Mg activation in AlGaAs by Mg+Ar and Mg+P dual ion implantation

Abstract

We have investigated Mg+Ar and Mg+P dual ion implantation into AlxGa1−xAs with a wide range of the Al fraction (0⩽x⩽0.75). We characterized the electrical properties and radiation damage of implanted AlxGa1−xAs layers to clarify the effects of dual implantation. Mg+P dual implantation, which maintained a stoichiometric balance, improved the electrical properties in AlxGa1−xAs for all Al fractions investigated. On the other hand, Mg+Ar dual implantation, which introduces additional radiation damage and increases the number of group III vacancies to enhance the Mg activation, improved the electrical properties in AlxGa1−xAs with a high Al fraction but degraded them in AlxGa1−xAs with a low Al fraction. The difference between Mg+P and Mg+Ar dual implantation is due to the different mechanism of Mg activation enhancement. The effect of keeping the stoichiometric balance is valid regardless of the Al fraction, and increasing radiation damage hardly affects the activation. In AlxGa1−xAs with a high Al fraction, the resistance against implantation damage is large. Here, Mg+Ar dual implantation effectively enhances the Mg activation. Conversely, in AlxGa1−xAs with a low Al fraction, a group III vacancy is easily created by only Mg implantation. Here, radiation damage caused by Mg+Ar dual implantation is too severe to remain even after annealing and degraded Mg activation.