Measuring system for testing electrical parameters of EMCCDs of various formats

This article describes the developed equipment that allows measuring the photoelectrical parameters of multielement photodetectors, specifically various formats of EMCCD (electron multiplying charge-coupled device) chips. The authors present the measuring techniques and test results on dark currents, output amplifier sensitivity, charge transfer efficiency, charge capacity and other parameters. The studies were conducted, both on the wafer and in the body, on samples of the following formats: 576×288, 640×512, 768×576, 1024×1024, and 1280×1024.В данной статье описывается разработанное оборудование, позволяющее измерять фотоэлектрические параметры многоэлементных фотоприемников, в частности, различных форматов микросхем ПЗСЭУ (приборы с зарядовой связью и электронным умножением). Представляны методы измерения и результаты испытаний на темновые токи, чувствительность выходного усилителя, эффективность переноса заряда, зарядную емкость и другие параметры. Исследования проводились на образцах следующих форматов: 576×288, 640×512, 768×576, 1024×1024 и 1280×1024, как на пластине, так и в корпусе.В даній статті описано розроблену вимірювальну систему, що дозволяє досліджувати фотоелектричні параметри багатоелементних фотоприймачів, зокрема ПЗЗЕМ різних форматів. Представлено методики та результати вимірювань темнових струмів, чутливості вихідного підсилювача, ефективності передачі заряду, зарядової ємності та інших параметрів. Дослідження проводилися на зразках формату 576×288, 640×512, 768×576, 1024×1024, 1280×1024 як на пластинах, так і в корпусах

Gamma radiation exposure of MCT diode arrays

Investigations of electrical properties of long-wavelength infrared (LWIR) mercury cadmium telluride (MCT) arrays exposed to gamma-radiation have been performed. Resistance-area product characteristics of LWIR n{+}-p photodiodes have been investigated using microprobe technique at T=78 K before and after an exposure to various doses of gamma-radiation. The current transport mechanisms for those structures are described within the framework of the balance equation model taking into account the occupation of the trap states in the band gap.Comment: 11 pages, 4 figures, submitted to Semiconductor Science and Technolog

Zero bias terahertz and subterahertz detector operating at room temperature

In this paper, the experimental study of the terahertz and subterahertz hot electron bolometer based on narrow-gap semiconductor compound Hg₁₋xCdxTe is presented. The measurements were performed in the temperature range from 77 to 300 K at various operating mode and frequency. The estimated value of the noise equivalent power at room temperature for detector proposed was 1.3·10⁻⁸ W/Hz¹/² and 5.4·10⁻⁹ W/Hz¹/² at bias current I = 1 mA and I = 0, respectively

Designing and manufacturing aspherical polystyrene lenses for the terahertz region

We report on the development of lenses for terahertz vision systems from their design up to manufacturing. Fused deposition modeling was used for assisting the 3D printing manufacturing process. HIP (High Impact Polystyrene) used for printing has high transmittance in the terahertz region and low deformation in the manufacturing process. The comparative analysis of experimental parameters data and the designed ones showed good agreement for the aspherical lenses manufactured. Application of the lenses manufactured to get imaging of some objects at 140 GHz radiation with 32 elements linear detector array has been demonstrated

Band-Offset and Electronic Properties of Type II PbTe/PbS Superlattices

Semimetallic conductivity was observed in PbTe/PbS SL obtained by a "hot wall" technique on (001) KCl substrates with (001) PbTe buffer layers. From the analysis of R$\text{}_{H}$(H) and p$\text{}_{⊥}$(H) dependencies by the Monte-Carlo fitting procedure the band offset ΔE$\text{}_{v}$ = 0.32 ± 0.05 eV was obtained (T = 77 K) and it was proved that these SLs are type II "misaligned" structures. The calculations of the band structure of PbTe/PbS SLs showed that in such SLs a semimetal-semiconductor transition should occur for layer thicknesses of about 60÷70 Å

CCD photomatrixes with electron multiplication

Electron multiplication charge coupled devices (EMCCD) technology is an innovation first introduced slightly more than a decade ago. The EMCCD is an image sensor that is capable of detecting an isolated photon without an image intensifier. It is achieved by electron multiplication circuit that is built in the chip of ordinary CCD. Cameras with EMCCD arrays overcome limitations of getting high sensitivity with high frame rate. Traditional CCD cameras can be highly sensitive in the visible part of spectrum but at the expense of low frame rate. EMCCD can operate at very faint illumination conditions both in visible and near infrared regions. The paper presents a short technological description of EMCCD 640×512 arrays manufacturing and some parameters of the arrays that were designed and manufactured. It was shown that multiplication coefficient depends much on applied amplification voltage and can achieve 1000. Also it is shown that images can be obtained at low illumination conditions (illumination at EMCCD is near 5·10-4 lx)

Medium wavelength infrared HgCdTe discrete photodetectors

The authors have developed the topology and technological fabrication route for discrete photodiodes (Θ = 0,5—1,5 mm) for the mid wavelength infrared (MWIR) range, based on the mercury-cadmium-telluride (MCT) epitaxial layers. The paper describes technological processes of MCT photodiodes fabrication, including CdTe passivation layers growth, photolithographic processes for the formation of windows for B+ implantation, formation of metallic coatings, chemical surface treatments, cutting of the wafer on the discrete chips, assembling and bonding of the electrical contacts. Optical, photoelectrical and current-voltage characteristics of discrete MCT photodiodes for the spectral range of 3—5 microns are investigated in order to achieve the necessary operational parameters. FTIR transmission spectra were measured to evaluate samples quality and find the composition of x of Hg1–xCdxTe epitaxial layers grown by liquid phase epitaxy method. The limiting characteristics of photodiodes, which are determined by the magnitude of the detector current at the reverse bias and the product of the dynamic resistance at zero bias by the area of the photosensitive element R0Ad at the operating temperature of 77 K were discussed. The requirement for the parameter R0Ad was estimated for the operation of photodiodes of the mid wavelength infrared range in the BLIP (background limited performance) mode for the angles of view qi = 90° and qi = 30°: R0Ad ≥ 5·103 Ω·cm2. It was found from dynamical resistance characteristics that without bias in these MCT MWIR photodiodes R0Ad ≈ (0,57—1,08) Ω · 105 cm2 and these photodiodes can operate in BLIP mode