High Performance Ingap Geiger-Mode Avalanche Photodiodes

In the past decades, significant improvement of the performance of III-V Geiger-mode APDs (GmAPD) has been achieved in Near Infrared (NIR) and Short Wavelength Infrared (SWIR) wavelengths. Their superior photo sensitivity promoted the evolution and penetration of many infrared camera and LAser Detection And Ranging (LADAR) technologies for both military and civilian applications. Now similar applications in visible wavelength have caught more attention for some special military and space applications.In order to meet the challenge to GmAPDs for these applications and new wavelength, Acqubit developed a GaAs-based InGaP APD with a substrate removal structure. With a mesa passivation process, very low dark current, similar to 0.5 nA in a 50-um diameter device or 25 uA/cm(2), was demonstrated just before breakdown at room temperature. Sufficient device thickness ensured an external quantum efficiency (QE) about 50% at 532 nm without a bottom reflector. The combination of mesa structure and substrate removal process greatly suppressed the array pixel crosstalk and afterpulsing while maintaining a high QE and photon detection efficiency (PDE).