Reliability of Various Size Oxide Aperture VCSELs

This paper presents AOC’s most recent work on 850-nm oxide aperture vertical cavity surface emitting laser (VCSEL) reliability. The VCSELs studied have a range of aperture diameters from about 5 to 20 μm and the reliability effect of aperture diameter is of principal interest in this paper. Larger apertures generally exhibit greater reliability. Electrostatic discharge (ESD) sensitivity thresholds of the various oxide aperture VCSELs is discussed, again showing dependence on diameter, with larger being better. Results for humidity exposure are presented. Here we find no aperture size dependence, because none of the tested designs show significant susceptibility to humidity-induced degradation. It is demonstrated that, in addition to end-of-life degradation, VCSELs generally exhibit variation of performance characteristics during the early part of operating life. This often leads to a requirement for device burn-in. AOC’s work in the area of wafer stabilization (trademarked under the name STABILAZE, patent pending) is introduced, showing how critical device parameters such as threshold and slope efficiency can be made to be unvarying over the product’s life without the need for costly component or module-level burn-ins.