Defect mechanisms in degradation of 1.3 micron wavelength channeled- substrate- buried-heterostructure (CSBH) lasers.

Defect mechanisms of both gradual and rapid degradations of channeled-substrate-buried-heterostructure (CSBH) lasers during accelerated aging have been studied in detail by transmission electron microscopy (TEM), convergent beam electron diffraction (CBED), electroluminescence (EL), energy dispersive x-ray analysis (EDX) and chemical etching (CE). The gradual degradation mode of CSBH lasers is characterized by (1) a gradual increase in room temperature threshold current; (2) a decrease in external quantum efficiency, typically a drop in peak value of dL/dl greater than 25%; (3) a drop in forward voltage at low current, indicating a change in junction characteristics; (4) ldV/dl exhibits a large peak below threshold (at around 3 mA); and (5) an enhancement in the peak in l sup 2 (d sup2 V/dl sup 2) at laser threshold.