Combined Mg/Zn p-type doping for AlGaInP laser diodes

• Comparison of Mg and Zn doping of Al(Ga)InP.
• Combination of a Zn-doped AlGaInP WG layer and a Mg-doped AlInP CL reveals diffusion interaction.
• Doping interaction between Mg and Zn enables desired doping profile.
• 632 nm LDs with more than 1 W output power per facet have been demonstrated.

Carbon-doped AlGaAs and AlInP doped with zinc or magnesium are compared as p-cladding material for laser diodes emitting around 633 nm. Mg doping of Al(Ga)InP is linearly dependent on the Cp2Mg flow rate after a doping delay in which a sufficient Mg coverage of the surface is built up. Laser diodes with Mg and Zn doped cladding were fabricated, compared and analysed by secondary ion mass spectrometry. Combining a Zn-doped AlGaInP waveguide with a Mg-doped cladding layer reveals diffusion interaction between Mg and Zn and results in enhanced Mg back diffusion into the waveguide counteracting the Mg doping delay. Laser diodes emitting at the wavelength of 632 nm with an output power of more than 1 W per facet have been demonstrated using this dopant combination.