Oxidation kinetics of AlAs and (AlGa)As layers in GaAs-based diode laser structures: comparative analysis of available experimental data

An understanding of the kinetics of the steam oxidation of AlAs and (AlGa)As layers is crucial to maintain good control of the process of manufacturing modern GaAs-based diode microresonator vertical-cavity surface-emitting lasers (VCSELs). Mathematically, the process has been described in our previous publications. Our theoretical equations contain, however, a few adjustable parameters, which should be found experimentally. Therefore, in this paper, an extensive analysis of existing experimental results (including ours) is performed. It enables us to extract the physical parameters describing oxidation kinetics for the AlAs and (AlGa)As oxidation process. While some scattering in the parameters is found from measurements reported by different groups, the same general trends are observed. These results support our physical understanding of the oxidation process. Nevertheless, the oxidation process still needs some experimental investigations to establish all conditions influencing its kinetics and to enable reproducible oxidation results obtained under assumed identical technological conditions. It has been confirmed that currently theoretical modelling cannot offer a reasonable a priori control of the oxidation process without a careful calibration of a given oxidation set-up and procedure. However, the simulation may enable determination of safe limits of the process, especially important in the fabrication of small-size microresonator VCSELs.