Thermomechanical model of an oxide-confined GaAs-based VCSEL emitter

A thermomechanical model for an oxide-confined GaAs-based VCSEL emitter is presented. The impact of the lattice mismatch, the oxide shrinkage and the thermal stress on the mechanical reliability is evaluated. Under standard operating conditions, calculations show that the temperature increase has a negligible influence on the overall mechanical stress. The oxide shrinkage highly deforms the epitaxial structure at the edge of the optical aperture. At oxide corners, the calculated stress is beyond the experimental yield strength of GaAs micro-pillars, enabling the nucleation of the dislocations forming dark line defects. The high misfit stress in the quantum well layers can favor there the dislocation propagation.