Imaging of defects in InGaAs/InP avalanche photo-detectors created during electrostatic discharge stress

摘要

InGaAs/InP avalanche photodiodes failed during electrostatic discharge tests at voltages between 700V and 1000V. A failure analysis using photoluminescence imaging revealed the formation of star-like defects on the aclive area of the devices having an inhomo-geneous photoresponse before the lest. Differential phase contrast images of the damaged device showed metal migration from the guard ring towards the defect location. The reverse bias currenl after degradation increased for several orders of magnitude. For the degraded photodiodes with defects on the active layer a negative differential resistance has been observed in the forward current-voltage characteristics.