Vol 52, No 4 (2023)

Using numerical simulation methods that take into account the dead time effect, algorithms are developed to calculate the detector’s response for photon fluxes with different photon number distributions, including the Poisson, Fock, and thermal distributions. Based on the results obtained, a detector tomography method is developed, as well as an algorithm for identifying the corresponding elements of a positive opera-tor-valued measure (POVM). Experimental studies using coherent states demonstrate close agreement between the calculation results and experimental data.

The electrical and physical characteristics of a cylindrical silicon field-effect nanotransistor (FET) with a fully enclosed gate with Al2O3 and HfO2 gate oxide dielectrics are discussed. The numerical simulation results show that the use of high k dielectrics has a noticeable effect on all the main characteristics of the tran-sistor compared to silicon oxide. It follows from the data obtained that, when scaling, the degree of degradation of the electrical and physical characteristics of the transistor is correlated with the level of k: it decreases with the growth of k. This is due to the fact that the decrease in the effect of the gate on the characteristics of the transistor structure, especially in the subthreshold region, is partially compensated by the use of dielectrics with a high k.

It was shown in [1, 2] that the dependence of the fault tolerance of a static RAM cell on the energy of secondary particles resulting from the action of a neutron flux does not take into account another signifi-cant factor—the part of the transistor in which these secondary particles are generated. In order to determine the area of the memory cell in which the impact of secondary particles can lead to a failure, the probability of a failure depending on the location of the occurrence of the secondary particle is studied. A method for ana-lyzing the accumulated charge is proposed for assessing the fault tolerance of a static random access memory cell depending on the place of occurrence of the secondary particle and the charge corresponding to the mar-gin of static noise immunity. The analysis is carried out based on the results of the instrumental-technological simulation of a single MOS transistor, which is part of a static RAM cell, and the integration of the obtained values of the current responses from the regions of the transistor.

A comparative study of the electrophysical parameters of the plasma, the fluorine atom concentra-tions, and the kinetics of reactive-ion etching of silicon in CF4 + O2, CHF3 + O2, and C4F8 + O2 mixtures of a variable (0–75% O2) initial composition is carried out. It is shown that the dominant etching mecha-nism is always the ion-stimulated chemical reaction Si + xF → SiFx, whose rate has a maximum in the region of 20–50% O2. Based on the results of plasma diagnostics, it is found that the similar behavior of the concen-tration of fluorine atoms is typical only for mixtures of CF4 + O2 and CHF3 + O2, while in the C4F8 + O2 mix-ture, there is a nonmonotonic change in the probability of the interaction. It is assumed that the latter effect is caused by the competition between the processes of reducing the thickness of the fluorocarbon polymer film and the oxidation of the silicon surface by oxygen atoms.

The results of studies of electrophysical parameters of pin-silicon-based photodiodes, depending on their operating modes (external bias and temperature), manufactured on single-crystal silicon wafers of p-type conduction orientation (100) with ρ = 1000 ohm cm, are presented. The p+-type region (isotype junction) is created by the implantation of boron ions; the n+-type region, by the diffusion of phosphorus from the gas phase. It is established that on the voltage-current characteristics under reverse bias, three regions of dark cur-rent variation depending on the applied voltage can be distinguished, sublinear, superlinear, and linear, caused by various mechanisms of the generation-recombination processes in the depletion region of the pn-junction. A noticeable dependence of the barrier capacitance value (at a frequency of 1 kHz) and the size of the depletion region on temperature is observed only when the applied reverse voltages do not exceed the contact potential difference (V ≤ 1 V).

Zinc oxide is one of the most promising materials used to create devices in the ultraviolet (UV) range. In this article, we study the sensor properties of ordered ZnO nanorod arrays grown by chemical vapor deposition. The possibility of their use as an indicator of UV radiation to control the dose of UV radiation, both from natural and artificial light sources, is assessed. The X-ray diffraction, Raman spectroscopy (RS), and cathodoluminescence (CL) data demonstrate the high quality of nanorods. Based on the ZnO nanorod array, a sensor prototype was fabricated based on the change in ZnO conductivity under the UV irradiation. A compari-son of the response of such a sensor with the readings of a UV radiometer showed a high correlation.

Magnetron sputtering in the medium frequency (MF) mode was used to obtain ITO films on glass substrates at room temperature in an oxygen-free environment. The effect of the magnetron sputtering power on the electrophysical properties and surface morphology of ITO films is studied. It is shown that the ITO film deposition rate depends linearly on the power of magnetron sputtering in the MF mode. It is found that ITO films have a predominantly nanocrystalline structure at a magnetron sputtering power of more than 100 W. Increasing the sputtering power leads to an increase in surface roughness from 13.5 to 24.6 nm and grain size from 11.7 to 27.5 nm in the ITO film. The minimum resistivity of the ITO films is 6.82 × 10–4 Ω cm at the concentration and mobility of charge carriers of 2.48 × 1020 cm–3 and 36.8 cm2/V s, which corresponds to the optimum power of magnetron sputtering of 200 W. The results obtained correspond to a high level of surface resistance values for ITO films (34.1 Ω/□), which can be used to form transparent conducting electrodes in solar cells and memristors, both on glass and flexible substrates.