Towards Surface Leakage Free High Fill-Factor Extended Wavelength InGaAs Focal-Plane Arrays

Abstract

By incorporating of a combined mesa cleaning of SF 6 plasma bombarding and HCl rinsing prior to the SiN x passivation, an ultra-low dark current density of 9.1 nA/cm 2 at 180 K under a reverse bias of -10 mV for 30 μm pitch In 0.83 Ga 0.17 As focal plane arrays (FPAs) with an extended cutoff wavelength of 2.6 μm has been achieved. Six times higher dynamic differential resistance-area product of 35 Ω · cm at 300 K and increased activation energies for dark current were also attained in comparison to reference FPAs. Shockley-Read-Hall lifetimes of ~40 and ~200 ns at 300 and 180 K were determined from theoretical simulation analyses, respectively. These results suggest such methods effectively remove the low resistance leakage pathways on the micro-mesa sidewall surfaces, and are essential for large format and high fill-factor FPAs with negligible surface leakage current.