REDR-based kinetics for line defects leading to sudden failures in 980 nm SL SQW InGaAs laser diodes

Abstract

Recombination-enhanced-defect-reaction (REDR) (Kymerling, Solid State Electron. vol 21, pp. 1391-1401, 1978) has been recently proposed (Magistrali et al. 1997) as the driving mechanism for sudden failures in 980 nm SL SQW InGaAs pump laser diodes for active fiber optics. The proposal follows a set of observations on life-tested devices that coherently lead to link the ultimate catastrophic failure to the growth of line defects from outside to inside the active layer. The most intriguing feature of the detected failure mode remains its sudden occurrence during constant-current life-tests, which is the total loss of the laser emission within a few tens of hours, after several hundred hours of perfectly regular operation. No correlation has ever been found between the occurence of that phenomenon and any of the many initial measurements that have been performed. The paper aims to account for the observed kinetics, based on the simple model of a native ideal point defect located within a few diffusion lengths from the edge of the depleted region of a laser diode. Its effect on the laser current is quantified, as well as the energy released to the lattice per unit time because of recombination at the defect neighbourhoods. The key point is to correlate that energy with some growth direction and speed, which leads to a model for the degradation kinetics.