In 2007, Teledyne presented and subsequently published an empirically derived formula, known as “Rule 07”, for the dark current performance of Mercury Cadmium Telluride (HgCdTe) P-on-n diodes. The Rule 07 metric has become widely popular within the infrared community, not only as a basis for predicting HgCdTe detector and system performance, but as the “number to beat” for other technologies, notably III-V nBn and strained-layer superlattice (SLS) devices. For materials that have sufficiently long recombination lifetimes, HgCdTe being one of the few such widely used materials, internal currents within the detector can be suppressed and the detector becomes limited by the background radiation from the surrounding environment. These currents can be orders of magnitude below Rule 07 and even further orders of magnitude below the Auger-limit. The ability to suppress Auger currents and operate at the radiative limit allows for significantly higher operating temperature and provides several significant advantages, including:
Reduced size, weight, power, cost, and improved reliability associated with reduced cooler requirements
Lower dark current when operating at conventional temperatures, permitting improved sensitivity from lower shot noise and longer achievable integration times
Because background radiatively-limited performance is both fundamental and physics-driven, in 2019 we proposed replacing Rule 07 with “Law 19” and provided a comparison of this fundamental limit with Rule 07. In this paper, we review the theoretical performance of Teledyne’s fully-depleted HgCdTe P-υ-N detectors and provide performance data on dark current, dynamic impedance and quantum efficiency (QE) for mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) detectors both at high operating temperatures (up to 300K) and as a function of temperature
Teledyne Judson Technologies (TJT) has developed high operating temperature (HOT) mid-wavelength infrared (MWIR) photodetectors based on InAs/InAsSb type-II superlattice (T2SL) with an electron barrier. Large area discrete detectors of 0.25mm and 1mm diameters were designed and fabricated for front-side illumination. Comprehensive E-O characterization was performed at room temperature and thermo-electric cooled (TEC) temperatures. The unique fabrication process was developed for a quasi-planar structure, enabling simplified fabrication for low-cost large volume production. The detector shows a 50% cut-off wavelength of ~5.5μm at room temperature. Peak responsivity of 2.47 A/W was achieved on 1mm detectors at peak wavelength ~ 4.24μm, -0.3V bias and 295K. Peak quantum efficiency (QE) was 72% with an antireflection coating. The 1mm detectors showed peak detectivity (D*) of 1.9x109 cm-√Hz/W at -0.3V bias, 295K and 10 kHz. Dark current density as low as 1.17 A/cm2 was achieved at -0.3V bias and 295K on 1mm detectors. The dark current was diffusion-limited at higher temperatures above ~120K while it was dominated by either tunneling or surface leakage currents at lower temperatures. Similar results were obtained on 0.25mm detectors.
An overview of DRS' development of a very unique two-color infrared photodiode architecture for two-color infrared focal-plane arrays based on Hg1-xCdxTe is given. One unique feature of this architecture is that it requires only a mono-color based on Hg1-xCdxTe material growth technique for its implementation. Some data from this development are presented.
An overview on DRS' approaches towards realization of HgCdTe photonic infrared detectors based on DRS's proven HDVIP technology is given. The first approach involves the use of a silicon microlens array attached to the detector array, and the second reduction of dark currents in each detector itself. Recent progress is presented.
An overview of the DRS HDVIP architecture for realization of large-area infrared focal plane arrays (IRFPAs) is given. Improvements needed to meet more stringent application requirements are discussed and modeled. Both theoretical and experimental data are presented.
Conference Committee Involvement (2)
Infrared Sensors, Devices, and Applications XI
1 August 2021 | San Diego, California, United States
Infrared Sensors, Devices, and Applications X
24 August 2020 | Online Only, California, United States