Active Surface Passivation for mesa type short-wave infrared InGaAs Photodetectors

We propose a gate-controlled device structure for mesa-type infrared photon detectors with the means of improving surface conditions. Additional terminal added to the pn-junction allows surface charges to be manipulated by applying a constant E-field through a metal-oxide-semiconductor (MOS) structure. Shortwave infrared (SWIR) Indium Gallium Arsenide (InGaAs) sample with a cut-off wavelength of 1.69 mu m is characterized. A theoretical framework is provided to gating mechanism. Experimental results show that, the shunt component of the dark current improved as high as 63% by interrupting the channel formation on the surface. Further improvements in the generation-recombination (GR) current is noted at more than 90% at 300 K. The effective GR lifetime of 20 mu s is obtained under 50 V/mu m surface-gate bias.