Evaluation of reactive ion etching processes for fabrication of integrated GaAs/AlGaAs optoelectronic devices

Reactive ion etching (RIE) was used for the fabrication of GaAs/AlGaAs optoelectronic devices (laser diodes and photodetectors) for optical interconnect applications. Smooth, vertical sidewalls with a smooth surface at the field were obtained after optimizing RIE conditions in BCl₃-formed plasma. Accurate in-situ monitoring of the etching process was realized by laser interferometry end-point detection. This led to good process control and reproducibility of the demanding fabrication of the optoelectronic devices. The RIE etching process did not affect the electrical properties of the device by increasing the surface recombination currents. Lasers with etched mirrors exhibited a threshold current density of 970 A cm⁻², which is one of the best values ever reported. The feasibility of a simple technology for the fabrication of optoelectronic circuits, based on a BCl₃ RIE process for laser mirror etching, has been demonstrated.