Smooth and anisotropic dry etching of InGaAlAs using Cl2/N2 ECR plasma

We developed a dry etching process for fabricating InGaAlAs laser mesa stripes and used it to fabricate an InGaAlAs-BH laser. We used optimized Cl₂/N₂ ECR plasma for the etching of an InGaAlAs laser multilayer structure. Use of this Cl₂/N₂ ECR plasma resulted in a uniform etching rate and resulted in an anisotropic etching by a nitrified side-protection mechanism. This smooth and anisotropic dry etching thus produced a well-matched interface between the etched surface and the semi-insulated Fe-InP regrown surface. The fabricated InGaAlAs-BH laser showed the stable operation at 85°C.