Low dark current diffusion limited planar type InGaAs photodetectors

In this work, we design and produce 1280x1024 format InGaAs based planar type detectors with 15μm pixel pitch. We have obtained diffusion current limited low dark current (~10fA) and high responsivity (1.08A/W at 1.55μm) values at room temperature conditions. Moreover, dark current modeling is performed using diffusion, generation and recombination (GR) and trap assisted tunneling (TAT) current mechanisms. Ideality factor is extracted from forward bias characteristics. Excellent match between modeling and experimental data is reached. Also, temperature dependency of dark current is studied in 10°C – 60°C ranges. The area and perimeter related dark current components are differentiated using test detectors with changing diameters that are placed next to the detector array structure. Experimental data shows good agreement with theoretical expectations.