A Novel Surface Preparation and Post-Etch Removal Technique for InGaAs Sidewalls

This paper describes in detail a surface preparation, and post-etch removal technique developed for InGaAs sidewalls. It illustrates the results demonstrating the effect of sidewall post-etch, surface preparation, and surface passivation on the performance of high speed InGaAs detectors. Dark current density for circular diodes with a diameter size varying between 10 and 100 μm was measured at a reverse bias voltage of −5 V. The effectiveness of various surface preparation techniques was studied by measuring the immediate improvement in dark current density, as well as its long-term stability. The benefits of this new technique compared to other techniques we have investigated include improved device characteristics, long-term stability, as well as a much less critical process to achieve optimum surface properties.