Micro-Raman studies of vertical-cavity surface-emitting lasers with AlxOy/GaAs distributed Bragg reflectors

Micro-Raman spectroscopy studies of the oxidation processes in high Al content AlxGa1-xAs layers used in distributed Bragg reflectors (DBRs) in vertical-cavity surface-emitting lasers (VCSELs) are presented. Precise characterization of the composition of oxidized layers, control over residual As precipitates, as well as the determination of the mechanical strain in DBR layers is demonstrated. Proper optimization of the processing steps on the basis of Micro-Raman spectroscopy allows the realization of reliable oxide-DBR VCSELs.