In this work, impurity-induced disordering by Zn diffusion is proposed as a method for lateral current confinement in InP-based quantum cascade lasers. This method improves current confinement for a shallow ridge-guide laser bar while preserving material for lateral thermal dissipation and avoiding an increase of optical loss. Using ZnAs2 solid source, the diffusion profiles and rates in an InGaAs/InAlAs superlattice is characterized. A diffusion coefficient of 7.35×10-12 cm2/s is extracted for a 550 ºC process. Zn-driven impurity-induced disordering of an InGaAs/InAlAs superlattice is experimentally demonstrated. Two-terminal electrical modeling is performed to verify improved confinement of the injected electrons. Furthermore, analysis of the optical mode is performed to determine the best mask and diffusion parameters. Optical modeling results indicate feasible diffusion profiles with a decrease in waveguide loss (from 13.041 cm-1 to 12.77 cm-1) and minimal change in gain overlap (51.15% to 51.13%). Finally, quantum cascade material is processed and electrically characterized with initial indications of a reduction of lateral current spreading by 61%.
