The effect of unintentional carbon incorporation on the electrical properties of AlGaAs grown by MOCVD

The materials of AlxGa1-xAs, as a wide application semiconductor material, have attracted a lot of attention. However, the unintentional doping is as an unsolved problem of the influence of materials properties, and has always been widespread concern. In this paper, the effect of unintentional carbon incorporation on the electrical properties of AlxGa1-xAs grown by MOCVD was studied. It was found that unintentionally doped carbon of n-type AlxGa1-xAs played an important role in moderating sheet resistivity. This could be explained by the recombination of intentionally doped Si atoms and unintentionally doped carbon atoms. The carbon incorporation was very strongly dependent on growth temperature, and the contents of unintentional impurity carbon affect the p/n crossover. On the other hand, conductive type conversion mechanism in AlxGa1-xAs were analysed. The result could be further to take a close look at the incorporation of unintentional carbon into the AlxGa1-xAs and lead to insights into the underlying chemical mechanisms of the MOCVD growth process.