Failure analysis of laser diodes by SEM and TEM

Degradation mechanism of InGaAsP/InP MQW laser diodes (LDs) has been studied using SEM and TEM. Artificial degradation was introduced into LDs by applying electrostatic discharge until the threshold voltage was raised. To study the mirror facet and cross-section along the stripes of degraded LDs by TEM, LD samples were thinned using a FIB technique. SEM and TEM observations suggest that the degradation firstly occurred at MQW–n-InGaAsP guided layer interface on the mirror facet: a melting had occurred with material transformation. And then successive melting was successively generated at MQW/n-guided layer interface to the inner direction along the stripe.