Development of high performance SWIR InGaAs focal plane array

Abstract

Banpil Photonics has developed a novel InGaAs based photodetector array for Short-Wave Infrared (SWIR) imaging, for the most demanding security, defense, and machine vision applications. These applications require low noise from both the detector and the readout integrated circuit arrays. In order to achieve high sensitivity, it is crucial to minimize the dark current generated by the photodiode array. This enables the sensor to function in extremely low light situations, which enables it to successfully exploit the benefits of the SWIR band. In addition to minimal dark current generation, it is essential to develop photodiode arrays with higher operating temperatures. This is critical for reducing the power consumption of the device, as less energy is spent in cooling down the focal plane array (in order to reduce the dark current). We at Banpil Photonics are designing, simulating, fabricating and testing SWIR InGaAs arrays, and have achieved low dark current density at room temperature. This paper describes Banpil's development of the photodetector array. We also highlight the fabrication technique used to reduce the amount of dark current generated by the photodiode array, in particular the surface leakage current. This technique involves the deposition of strongly negatively doped semiconductor material in the area between the pixels. This process reduces the number of dangling bonds present on the edges of each pixel, which prevents electrons from being swept across the surface of the pixels. This in turn drastically reduces the amount of surface leakage current at each pixel, which is a major contributor towards the total dark current. We present the optical and electrical characterization data, as well as the analysis that illustrates the dark current mechanisms. Also highlighted are the challenges and potential opportunities for further reduction of dark current, while maintaining other parameters of the photodiode array, such as size, weight, temperature of peak performance (lowest dark current), and power consumption.

Strategic options towards an affordable high-performance infrared camera

“…ahead of its time, but trending. Banpil has successfully employed this strategy in perfecting our FPA to become a leading low dark current device [6] working with one Fab. We are now working on fabricating our high density small pixel FPA with a target of 5 μm pitch with another Fab.…”

High efficiency metastructure-based emitter and photodetector for imaging

“…Although this work is focused on APDs, the same metastructure is equally applicable to conventional p-i-n detectors. [7][8][9][10] Furthermore, compared to detectors with photonic structures etched into the active layer such as pillars and holes, 10,11 the present metastructure does not expose additional sidewall surfaces. Leakage current along these surfaces can thus be avoided.…”