Electrostatic discharge induced degradation of optical-electrical properties and defect evolution of GaAs-based oxide-confined VCSELs

Abstract

GaAs-based oxide-confined vertical-cavity surface-emitting lasers (VCSELs) exhibit relatively low resistance against reliability-related damage. In order to gain a deeper understanding of the degradation and failure mechanism in oxide-confined VCSELs caused by electrostatic discharge (ESD)-induced defect proliferation, we investigated the effects of ESD stress on the degradation of optical-electrical characteristics and the evolution of defects in VCSELs under human body model test condition. The degradation threshold values for forward and reverse ESD pulse amplitudes were estimated to be 200 V and -50 V, respectively. Notably, VCSELs demonstrated greater sensitivity to reverse bias ESD compared to forward bias ESD. Analysis of optical emission and microstructure provided evidence that the device failure is attributed to an increase in ESD current density, leading to the multiplication of dark line defects (DLDs) originating from the edge of the device's oxide aperture. The formation of defects occurred suddenly in discrete events within small regions, rather than progressing gradually and uniformly. These defects propagated and led to damage across the entire active region. We believe that our results would be meaningful for improving the reliability of VCSEL in the future.

Reliability and failure mode analysis of high-speed 850-nm multi-mode and 795-nm single-mode VCSELs for space applications

“…We performed failure mode analysis (FMA) of life-tested and ESD tested VCSEL failures using optical beam induced current (OBIC), electron beam induced current (EBIC), and photocurrent spectroscopy. Several groups employed OBIC techniques to study degraded VCSELs, but most of these studies dealt with VCSELs exposed to ESD [12,13]. As our group reported in our previous publication [14], plasma FIB was employed for local removal of top-DBR mirrors of degraded VCSELs for EBIC techniques as well as for slice-and-view techniques.…”