Effect of Substrate Removal on the Optoelectronic Properties of GaAs Epitaxial Layers and GaAs/AlGaAs Vertical-Cavity Surface-Emitting Lasers

We measured the electron Hall mobility of Si-doped GaAs epitaxial layers (ELs) that were flip-chip-bonded onto an alumina mount to investigate how the quality of the thin layer changes before and after GaAs substrate removal. The electron Hall mobilities at room temperature before and after substrate removal were almost unchanged. Photoluminescence spectra after substrate removal exhibited peak wavelengths at 872-874 nm, which were almost equal to those before substrate removal. This indicates that the quality of ELs was maintained after the process. We measured near-field patterns (NFPs) and far-field patterns (FFPs) of GaAs/AlGaAs vertical-cavity surface-emitting lasers with and without a substrate. There was no change in the full-width-at-half-maximum of the NFP or in the FFP for the optical output range of 0.5-1.3 mW. We confirmed that our novel process is useful for optoelectronic packaging.