Research Institute of Molecular Electronics

In this paper, we demonstrate the double pattening (DP) technique with an anti-spacer, which allows the formation of critical layer structures with sub-193i-lithographic dimensions that go beyond the limits of single extreme ultraviolet lithography (EUV). The set of key parameters affecting the performance of the process is studied and a method for optimizing the lithographic process is presented.

In this work, we discussed how the CF4/CHF3 ratio in CF4 + CHF3 + O2 gas mixture does influence steady-state plasma composition and silicon etching kinetics in a conventional reactive-ion process. Plasma diagnostics by double Langmuir probes delivered the information on electro-physical plasma parameters and provided input data for the modeling of plasma chemistry. As a result, we confirmed basic properties of CF4 + O2 and CHF3 + O2 plasmas known from previous works as well as analyzed formation/decay kinetics for plasma active species in the three-component gas mixture. In particular, it was found that the substitution of CF4 by CHF3 at fixed content of oxygen in a feed gas a) causes weak changes in electron temperature and plasma density; b) leads to an increase in plasma polymerizing ability; and c) sufficiently (by more than 3 times) reduces F atom density. The last effect was confirmed by the satisfactory agreement with experimental data obtained using the optical emission actinometry method. Etching experiments indicated a monotonic decrease in Si etching rate toward CHF3-rich plasmas, from 140 nm/min down to 65 nm/min. The analysis of etching kinetics allowed one to conclude that a) the dominant etching mechanisms is the ion-assisted chemical reaction; and b) the effective reaction probability keeps the nearly constant value, in spite of increasing polymer deposition rate. This effect may reflect the change in passivation of polymer-free surface by oxygen atoms. For citation: Efremov A.M., Bobylev A.V., Kaznacheeva E.M., Kwon K.-H. On effects of initial CF4 + CHF3 + O2 mixture composition on plasma parameters and reactive-ion etching of silicon. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 1. P. 39-47. DOI: 10.6060/ivkkt.20256801.7096.

The generation characteristics of a laser with a Fe:CdTe single crystal grown by a modified vertical gradient freeze method and subjected to high-temperature treatment as an active element have been studied. The possibility of efficient pumping using Fe:ZnSe or deuterium fluoride laser has been demonstrated. The broadband generation in the range of 5.3-6.0 $\mu \mathrm{m}$ with a maximum energy of up to 0.35 J per pulse has been obtained.

В работе измерены суммарные потери акустических волн в пластинах 128°Y-LiNbO3 при нанесении жидкости, обусловленные радиационным излучением волн в жидкую среду, а также ее вязкостью, электропроводностью, плотностью и диэлектрической проницаемостью жидкостного аналита. В качестве тестируемых выбраны растворы с 5-ю базовыми вкусами, широко применяемые для калибровки и создания эталонов при тестировании жидких сред. Измерения проведены в диапазоне 30…60 МГц. Экспериментальные данные были представлены в виде полярных гистограмм, из сравнения площадей и формы которых определялся вкус того или иного раствора. К тем же экспериментальным результатам был применен метод анализа большого массива данных (РСА) для описания линейных процессов деформации упругих волн на основе экспериментальных данных, содержащих известные значения измерений физических показателей волны для различных типов жидкостных сред, который ранее использовался для идентификации газов и предсказания свойств различных веществ по линейному отклику нормальной акустоэлектронной волны. Выполнен сравнительный анализ результатов, полученных с помощью полярных гистограмм и стандартного метода классификации РСА. Продемонстрированы преимущества последнего. Результаты данного исследования полезны как при разработке акустических датчиков без сенсорных слоев, так и для применения методов машинного обучения к данным в других типах датчиков.

Demonstrated the influence of buffer layers of group IVB oxides on the electrophysical characteristics of ferroelectric memory storage elements with a hafnium oxide functional layer. Thin films of buffer and functional layers were deposited by plasma-enhanced atomic layer deposition using the Russian system "Izofaz TM-200K-01." It was experimentally found that the introduction of thin-film buffer layers reduces the drop in the value of residual polarization after heating. Zirconium oxide buffer layers positively effect of the memory window of the storage element, and titanium oxide buffer layer allows reducing the influence of the imprint effect and increasing the value of the remnant polarization and switching endurance.

Using examples of an exothermic chemical reaction and self-heating of the region of a conducting filament of a memristor, heat-induced phase transitions, disadvantages of applying the classical Fourier approach on the nanoscale, and advantages of the molecular mechanics method at modeling the temperature factor are discussed. The correction for Arrhenius relationship, taking into account that the temperature becomes a random variable is proposed. Based on the introduced concepts (elementary act of heat release, distance and region of thermal impact) method for taking into account the thermal factor, is proposed.The correction is based on splitting the entire pool of particles into several, each of which corresponds to a fixed temperature value taken from a certain range. Although continuous and discrete correction options are given both, but the discrete option is more preferable. This is due to the fact that the methodology focuses on the application of methods of molecular mechanics, and, intentionally, in the most primitive version. The role of amorphization is noted as an example of the structural restructuring of matter in nano-volumes. It is indicated that the phonon spectra themselves, which determine heat transfer, depend on temperature. The technique is consistent with the ideology of multiscale modeling. The integral temperature increase is calculated outside the region of thermal exposure, where nonequilibrium effects are significant, by solving the standard equation of thermal conductivity.

In this work, using numerical simulation, the reasons for the occurrence of increased values of leakage currents in NMOS fully depleted SOI (FD-SOI) transistors during interaction with ionizing radiation. It has shown that the main reason for the formation of leakage currents is the charge accumulated in the latent oxide upon interaction with ionizing radiation. The effectiveness of applying a bias on the substrate and the formation of a well under the buried oxide (BOX) to reduce the leakage currents is investigated. Based on the obtained results, it was concluded that it is promising to use transistors made using FD-SOI technology for space applications.

The study of the selectivity of the plasma etching of functional materials with respect to the mask of a negative electron resist based on hydrogen-silsesquioxane (HSQ) has been carried out. The formation of nanostructures with sub-50 nm critical dimensions by the HSQ mask has been studied for a number of materials: single-crystal silicon, a metallic Ta layer, dielectric layers of SiO₂, Al₂O₃, HfO₂, Si₃N₄, as well as a porous low-k dielectric based on organosilicate glass (OSG) on silicon substrates. It has been found that HSQ resist masks can be used to manufacture prototypes of microand nanoelectronic devices with critical dimensions less than 10 nanometers using a large number of materials, including for creating structures with relatively high aspect ratios with an absolute thickness of layers of functional materials of tens of nanometers.

Non-stoichiometric silicon nitride SiNx, enriched with silicon, is a promising material for the non-volatile resistive memory development. The current studies devoted to investigation of the optical properties of SiNx synthesized in a low-pressure reactor at 800oC at different ratios of dichlorosilane (SiH2Cl2) to ammonia (NH3). It was found that for films synthesized at SiH2Cl2/NH3=1/1, 1/2 and 1/3, the corresponding bandgap values are 3.83, 4.17 and 4.40 eV. At the same time, the corresponding values of the parameter x, found according to the theoretical dependence of the bandgap value on x for SiNx calculated from the first principles, are 1.26, 1.30 and 1.32. Thus, by increasing the SiH2Cl2/NH3 ratio, it is possible to create non-stoichiometric SiNx films with a controlled silicon enrichment degree with high uniformity of chemical composition and thickness. Keywords: silicon nitride, memristor, absorption coefficient, ellipsometry, quantum chemical modeling.