The 15-μm-pitch 640×512 FPA detectors with a long-wavelength sensitivity limit of 5.1 μm based on MCT layers grown by molecular-beam epitaxy on Si substrates were designed and fabricated. Both electrical circuit and topology of a 15-μm-pitch 640×512 ROIC for such FPAs were developed, according to which multiplexers ensuring operation of manufactured FPAs at a clock frequency of up to 20 MHz were fabricated. Using the flip-chip method on In bumps, hybrid 640×512 MCT-based FPA detectors with 15-μm pixel pitch were obtained. The best fabricated FPA detectors were found to have the following characteristics: mean NETD value < 18 mK and number of non-defective pixels > 99.8%.

The interface between Cd 0.22 Hg 0.78 Te and HfO 2 grown by plasma-enhanced atomic layer deposition at a temperature of 120 o C in a specifically optimized deposition mode has been studied. The method used in this work for measuring the admittance of metal-dielectric-semiconductor structures made it possible to establish that their electrophysical parameters are uniform over the sample surface. The spectrum of fast surface states density at the HfO 2 -Cd 0.22 Hg 0.78 Te interface has been calculated. Keywords: CdHgTe, HfO 2 , ALD, C-V, passivating coating.

We investigate the HfO2/Hg0.78Cd0.22Te interface fabricated by plasma-enhanced atomic layer deposition (PEALD) at 120 °C During the deposition of HfO2, no donor-like defects are introduced into mercury cadmium telluride. X-ray photoelectron spectroscopy and ellipsometry were used to establish the optimal process regime at 120 °C and to demonstrate how HfO2 layer composition and growth rate per cycle depend on post-plasma purge time; the optimum is achieved at 6 s. Increasing the post-plasma purge time decreases the carbon and nitrogen impurity concentration in the HfO2 layer. Measurements of the admittance of metal-insulator-semiconductor (MIS) structures over the surface of a sample show that the electro-physical properties are uniform. We discuss the method of measuring the admittance of MIS structures that allows us to minimize the contribution of slow states with trapped charge on shape and shift of the C–V curve. The results demonstrate that the densities of fixed charge, slow states, and fast interfacial traps at the HfO2/MCT interface are greater than that for Al2O3/MCT (also formed by PEALD). The interface trap density is estimated from a normalized parallel conductance map, and the HfO2 film adheres well.

The interface between Cd0.22Hg0.78Te and HfO2 grown by plasma-enhanced atomic layer deposition at a temperature of 120 ℃ in a specifically optimized deposition mode has been studied. The method used in this work for measuring the admittance of metal-dielectric-semiconductor structures made it possible to establish that their electrophysical parameters are uniform over the sample surface. The spectrum of fast surface states density at the HfO2 - Cd0.22Hg0.78Te interface has been calculated.

The modern tendencies of development of infrared detectors based on HgCdTe heterostructures are fabricating photoconductors and photodiodes type focal plane arrays (FPA). For producing of high quality FPA’s it is necessary to grow HgCdTe with high uniformity properties over the large surface area. The growth of HgCdTe heteroand nanostructures on GaAs and Si substrates allows to decrease the cost of HgCdTe material and essentially to simplify the technological process of FPA fabricating. The investigations of development of HgCdTe heteroand nanostructures growth on GaAs substrates are presented. Multi-chamber MBE installation for growth of HgCdTe epilayers on GaAs and Si substrates up to 4” in diameter with precise control of films quality in situ allows to solve many problems connected with the producing high uniformity MCT layer composition over the surface area and control the MCT composition throughout the thickness. The defects formation mechanisms, its nature, the parameters characterization allows are presented.The growth of HgCdTe heterostructures with different composition distribution throughout the thickness allows to prepare material with unique properties that lead to simplification of fabricating high quality IR detectors on their basis. The new fields of science are connected with different new physical phenomena studied on HgCdTe nanostructures such as single or multilayer quantum wells (QW). The results of HgCdTe based QW mostly HgTe QW growth with ellipsomentric control and parameters measurement are presented. The application of HgCdTe heterostructures for different IR detector type is presented. We presented the results of study of different HgTe QW in field of carrier transport, interaction with THz radiation, for laser radiation, 2D and 3D TI etc.

We provide a review of the current state, problems and their solutions, and potential possibilities to develop the technology of the Molecular Beam epitaxy (MBE) to obtain CdHgTe structures on various substrates for infrared detectors. We present the data about MBE supervacuum units control tools for growth processes, collected according to used substrates preparation processes for substrate surfaces, growth of buffer layers on alternating substrates, and growth and alloying of CdHgTe layers. We present main defects of structures (such as line defects and macrodefects) and their least achieved concentration levels limiting the quality of detectors. We consider the data about problems of the external alloying of CdHgTe layers by dopants and the obtained electrophysical parameters of such layers. We provide photoelectric parameters of IR-detectors, close to theoretical ones and showing that the MBE technology is ready to produce CdHgTe/Si structures on six-inch diameters. We demonstrate results of the research and development of the growth and alloying of CdHgTe structures on GaAs substrates and Si substrates of 76.2-mm diameters, implemented at the Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences.

Охлаждаемые детекторы ИК излучения являются незаменимыми в широком поле различных применений, включающих промышленное оборудование, военную и спецтехнику, аэрокосмические и метеорологические средства наблюдения. Приборы с наилучшими характеристиками изготавливаются на основе тройного раствора CdxHg1-xTe (КРТ), позволяющего за счет состава реализовать чувствительность во всем ИК диапазоне. Таким образом способность осуществлять разработку и создание приборов на основе КРТ является одним из критических условий для обеспечения государственной безопасности и технологического лидерства.

The effect of the different surface treatment of Hg $${}_{1-x}$$ Cd $${}_{x}$$ Te (CMT) films before the atomic layer deposition of Al $${}_{2}$$ O $${}_{3}$$ dielectric on the charge at the dielectric–semiconductor interface has been studied. Metal–dielectric–semiconductor (MDS) structures with different surface treatment before the deposition of a dielectric have been manufactured. The capacitance–voltage characteristics of CMT based MDS structures have been measured alongside with the surface charge density. The surface charge is non-uniformly distributed over the surface of films with $$x=0.22$$ and a natural oxide layer and equal to $$(0.8{-}1.8)\times 10^{-8}$$ C/cm $${}^{2}$$ , and this may lead to the inversion of the surface conductivity type. The exposure of these CMT structures in mercury vapor at room temperature leads to the formation of a negative charge within a range of $$-(0.4{-}1.6)\times 10^{-8}$$ C/cm $${}^{2}$$ .

Matrix photosensitive elements based on a HgCdTe semiconductor solid solution on silicon substrates with 640 × 512 elements at a pitch of 25 μm with a long-wavelength sensitivity of 5 μm at half maximum are designed and produced. The scheme and topology are developed according to which matrix multiplexers with 640 × 512 elements at a pitch of 25 μm, which ensure operating modes at a clock frequency up to 10 MHz, are manufactured. Using a hybrid assembly method on indium bumps, a matrix photodetector with 640 × 512 elements at a pitch of 25 μm is produced. The best photodetector specimens are characterized by the following parameters: average NETD value <13 mK and the number of workable elements > 99.5%.

Results of measurement of the dark currents and photocurrents of p-on-n photodiodes (PD) formed in In-doped MBE-grown n-type mercury cadmium telluride (MCT) films are reported. We used 3 in. in diameter (0 1 3) GaAs and (0 1 3) Si substrates. The p-on-n junctions were fabricated using the implantation of As+ ions followed by the thermal annealing activation. It was shown that the regime of background-limited performance (BLIP) of the p-on-n PD with experimentally measured long-wave cutoff wavelength (LW) cutoff (lambda(c)) of 11.1 and 10.3 mu m at 77 K is observed up to elevated temperatures of 105 K and 117 K, respectively. The temperature dependence of the noise equivalent temperature difference (NETD) for p-on-n PD sized 30 x 30 mu m was calculated taking into account only PD shot noise. It was shown that such LW p-on-n photodiodes allows to increase the operating temperature of IR FPA detectors up to 100-105 K with the NETD less than 30 mK.

We report on the relaxation of Hall coefficient RH (77 K) depending on the magnetic field in p-CdxHg1−xT (x = 0.222) to the initial values, which were before the plasma etching process in argon and methane plasma. The time required to change the conductivity type from the n-type, which was created on the sample surface at a depth of around a micrometer, to the p-type is less than 165 min. We show that the electron concentration in the thin layer near the sample surface decreases to an insignificant value with the increasing storage time at room temperature.

We report an experimental study of the electrical properties of the interface between the Al 2 O 3 passivating coating grown by plasma enhanced atomic layer deposition at different temperatures and the p -CdHgTe ( x CdTe = 0.22) coating grown by molecular beam epitaxy via measuring the C – V characteristics of MIS structures. It has been established that, at an Al 2 O 3 growth temperature of 200°C, the concentration of acceptors in CdHgTe increases due to dissociation and, at a temperature of 80°C, the spread of the insulator capacitance and built-in charge increases. The optimum temperature for growing the passivating Al 2 O 3 coating on CdHgTe lies in the range of 120–160°C.

The electrophysical interface properties of the passivating Al2O3 coating grown by the method of plasma-induced atomic layer deposition at various temperatures on MBE p-CdHgTe (x = 0.22) was experimentally studied by measuring the capacitance-voltage characteristics of MIS structures. It was found that, at a temperature of Al2O3 growth of 200 °С in MCT, the concentration of acceptors increases due to dissociation. At a temperature of 80 °С, the spread in the capacitance of the dielectric and the built-in charge increases. The optimum growth temperature of the passivating Al2O3coating on CdHgTe lies in the range of 120-160 °С.

В настоящее время твердые растворы Hg1-xCdxTe (кадмий-ртуть-теллур, КРТ) занимают лидирующее положение среди материалов, на основе которых разрабатываются инфракрасные фотоэлектрические детекторы излучения. Благодаря тому, что HgTe обладает инвертированной зонной структурой или, иначе, «отрицательной» шириной запрещенной зоны, в твердом растворе Hg1-xCdxTe можно получить произвольную ширину запрещенной зоны от 0 до 1.6 эВ и настроить детектор на выбранное окно прозрачности атмосферы. Использование подложек из CdZnTe позволяет выращивать эпитаксиальные структуры CdHgTe с низкой плотностью прорастающих дислокаций. Однако, несмотря на затраченные гигантские усилия и средства, подложки большой площади из CdZnTe остаются дорогим и эксклюзивным изделием с невоспроизводимыми характеристиками. В связи с этим повсеместно разрабатываются технологии создания гетероструктур CdHgTe на альтернативных подложках, таких как Si, GaAs, Ge. Использование подложек из кремния позволяет получать матричные фоточувствительные элементы, согласованные по коэффициенту термического расширения с кремниевой интегральной микросхемой считывания сигнала (мультиплексором). Большое различие параметров кристаллических решеток, химическая и структурная несогласованность КРТ на Si делает задачу разработки и изготовления ИК ФП на основе гетероструктур КРТ/Si, с параметрами, не уступающими параметрам ИК ФП на основе структур КРТ на согласованных подложках CdZnTe, чрезвычайно сложной. В ИФП СО РАН разработано и изготовлено уникальное российское оборудование для выращивания КРТ методом МЛЭ. Проведены комплексные исследования всех этапов выращивания гетероэпитаксиальных структур CdTe и CdHgTe на подложках из арсенида галлия и кремния ориентацией (013) диаметром до 100 мм. Подложки, ориентированные по плоскости (013) выбраны нами, так как они позволяют выращивать слои КРТ с высокими параметрами в более широком диапазоне условий роста по сравнению с наиболее часто используемыми подложками (211). Исследованы механизмы формирования гетеропереходов АIIВ VI/GaAs и АIIВ VI/Si и кинетика роста слоев CdZnTe и CdHgTe на высокоиндексных поверхностях. В результате разработана технология, позволяющая создавать на альтернативных подложках нелегированные и легированные In пленки CdHgTe с низкой плотностью морфологических и структурных дефектов. Установлено, что в пленках МЛЭ КРТ/Si вне зависимости от состава наблюдаются магнетополевые зависимости проводимости и коэффициента Холла в диапазоне магнитных полей 0,05÷1Тл при 77K. Эти зависимости хорошо описываются с привлечением двух типов электронов: с высокой и с низкой подвижностью, различающимися на порядок величины. Установлено, что в гетероструктурах КРТ/Si(013) доминирующим генерационнорекомбинационными уровнями являются уровни, связанные с вакансиями в подрешетке металла. Заполнение вакансий приводит к снижению вклада рекомбинации Шокли-Рида и к возрастанию времени жизни неосновных носителей заряда в несколько раз до величин ограниченных фундаментальными межзонными механизмами рекомбинации. На полученных структурах изготовлены матричные фотоприемники различного формата на диапазоны длин волн 1-3, 3-5 и 8-14 мкм, работающие как при 77K, так и повышенных температурах, с параметрами не уступающими зарубежным аналогам. Впервые изготовлен фотоприемник формата 2000×2000 элементов для средневолнового спектрального диапазона.

Abstract—The characteristics of MWIRs focal plane aeeays made in the form of a hybrid chip based on a planar n+–p-HgCdTe focal matrix with 2048 × 2048 elements and a silicon multiplexer are considered. The temperature dependence of the reverse current of elements in the 125–300 K range had a characteristic Arrhenius dependence with an activation energy close to the band gap of the semiconductor and was limited by the diffusion component of the current. At a lower temperature, the current was limited by the generation of carriers with the participation of a deep level near the middle of the forbidden band. The histogram of the detectability of the elements of the matrix had the form of a symmetric curve with a maximum and an average value ≈ 1.3 × 1012 cm Hz1/2/W.

Diffusion of charge carriers in the photosensitive film of infrared mercury-cadmium-tellurium (MCT) focal plane arrays (FPAs) is simulated by the Monte Carlo method for determining the spatial resolution of these FPAs. Calculation results for matrix and linear FPAs with variously designed FPA pixels, including configurations with isolating diodes, are reported. The calculated data are compared with the experimentally measured resolution values of real FPAs.

Abstract—Design and fabrication of photosensitive array elements in the 384 × 288 element format with a step of 25 μm with a long wavelength limit of sensitivity at 0.5 to approximately 9.5 μm were performed. The circuit and topology were developed, according to which matrix high-speed multiplexers are manufactured in the form of 384 × 288 elements with a step of 25 microns, which provide operating modes at a clock frequency of up to 20 MHz. The 384 × 288 element hybrid photodetector (PD) format in 25 μm increments has an average Noise Equivalent Temperature Difference (NETD) of less than 30 mK, while the number of working elements was more than 97%. Examples are given of using the microscanning system to reduce defective pixels in an image frame and/or increase the frame format to 768 × 576. It is shown that as a result of the use of microscans in a thermal imaging channel based on the developed PD during the transition to the 768 × 576 format, an improvement in spatial resolution of 1.4 times was obtained for the same minimum resolved temperature difference (MRTD), while the MRTD at a frequency of 0.44 mrad-1 decreased from 1.6 to 0.9 K compared to the original 384 × 288 format.

Impact of high-conductivity n-type anti-debiasing layer (ADL) on the photoresponse of focal plane array (FPA) elements in mercury-cadmium-tellurium based photovoltaic n-on-p infrared FPA detectors is analyzed via consideration of, first, measured current-voltage characteristics of FPA elements with “leaking” and “non-leaking” array photodiodes and, second, spatial photoresponse profiles measured using FPA elements of both types. A most pronounced manifestation of the parasitic diode with the p-n junction at the absorber layer/ADL interface consists in the emergence of negative photoresponses produced by the “leaking” FPA elements.