Highly reliable InGaAsP/InP lasers with defect-free regrowth interfaces formed by newly composed HBr-based solutions

The reliability of buried heterostructure laser diodes (BHLDs) that have a dry-etched mesa structure has been improved by about ten times by using optimized HBr-based wet chemical etchants. This improved reliability was achieved by reducing the amount of defects at the regrowth interfaces by using a newly optimized HBr-Br₂-H₂O solution with a composition range from 0.30 M HBr/0.022 M Br₂ to 0.50 M HBr/0.020 M Br₂. Solutions in this range produce the same etching rates of the (1¯10) InP cladding layers and the (1¯10) InGaAsP multi-quantum-well active layer. The etching mechanism of the InGaAsP/InP material system in the HBr-Br₂-H₂O solutions was found to be an oxide-dissolution reaction