Fabrication of 1.55 /spl mu/m In/sub 0.53/Ga/sub 0.47/As/In/sub 0.53/(Ga/sub 0.6/Al/sub 0.4/)/sub 0.47/As SCH MQW laser with InGaAlAs digital alloy by post-growth rapid thermal annealing using dielectric capping layers

We fabricated MBE-grown InGaAs/InGaAlAs SCH MQW ridge-waveguide lasers with InGaAlAs digital alloy layers after post-growth rapid thermal annealing using an SiO/sub 2/ capping layer. The lasers fabricated on as-grown substrate and annealed substrates were compared by I-V and I-L measurements. The electrical characteristics of the annealed lasers were not degraded by the annealing process compared to those of as-grown lasers. The threshold current and slope efficiency of the fabricated lasers were improved with the increase of RTA temperature. For a 10-/spl mu/m-wide and 600-/spl mu/m-length laser fabricated after an RTA of 850/spl deg/C for 45 sec, the internal quantum efficiency of about 27.6% per facet and the threshold current density of about 1.53 kA/cm/sup 2/ were obtained at room temperature.