Dry-etched 650 nm AlGaInP visible-light laser diodes with operating time of over 3000 h

The authors have achieved CW operation of 650 nm GaInP/AlGaInP index waveguide-type visible-light laser diodes (LDs) with dry-etched mesa stripes fabricated by Cl₂ reactive ion beam etching. The threshold current of 47 mA and slope efficiency of 0.40 W/A are almost the same as those of a wet-etched LD fabricated from the same wafer (L=500 μm). The cross-sectional scanning electron microscope view of the buried mesa stripe shows that the dry-etched LD has a symmetric mesa shape resulting in a small focusing spot and stable mode operation. The wet-etched mesa, however, is asymmetric because a 6° misoriented substrate is used for this wavelength operation. An aging test with light output power of 3 mW at 50°C has revealed that these LDs have an operating time of over 3000 h, which represents a sufficient reliability for conventional uses