Home – Home – Jornals – Avtometriya 2017 number 6

Results of studying the errors of indirect inspection by means of computer simulations are reported. The inspection method is based on measuring spectra of reflection from additional reference substrates in a wide spectral range. Special software (Deposition Control Simulator) is developed, which allows one to estimate the influence of the inspection system parameters (noise of the photodetector array, operating spectral range of the spectrometer and errors of its calibration in terms of wavelengths, drift of the radiation source intensity, and errors in the refractive index of deposited materials) on the random and systematic errors of deposited layer thickness measurements. The direct and inverse problems of multilayer coatings are solved by using the OptiReOpt library. Curves of the random and systematic errors of measurements of the deposited layer thickness as functions of the layer thickness are presented for various values of the system parameters. Recommendations are given on using the indirect inspection method for the purpose of reducing the layer thickness measurement error.

This paper presents the results of modeling the most important component of a one-stage technology of writing kinoform lenses in thick photoresist layers with increased diffraction efficiency, involving the formation of reverse slopes of Fresnel zones with a steepness up to 90º by means of inclined laser beams. It is shown that this technique for writing volumetric structures in photoresists with low contrast (k = 3) make it possible to significantly increase the steepness of the inverse slopes of the zones, and in photoresists with an average contrast (k = 10), to form practically steep slopes.

The characteristics of the observed shift of spectral structures caused by the Zeeman effect in a spatially inhomogeneous magnetic field have been studied. It has been found that this shift can be varied by changing the width of the spectral structures, their forms, and methods and conditions of recording.яA method of accounting for the inhomogeneity of the magnetic field for optically thin and thick media has been proposed.

A three-axial microoptoelectromechanical (MOEM) angular rate transducer model based on the optical tunneling effect has been developed. The transfer function has been determined, and the effect of destabilizing factors on the characteristics of the triaxial MOEM angular rate transducer has been evaluated. The dynamic range of the MOEM transducer based on the optical tunneling effect has been calculated.

Scanning devices based on multiple-row focal plane arrays providing increased resolution impose much more strict requirements on alignment than single-row arrays. This paper presents a new method for measuring and estimating the scanning speed and the angle of orientation of a multiple-row focal plane array relative to the scanning direction - parameters that have the most significantly effect on the quality of the discrete image formed. The method is based on an analysis of the image of a simple test object - an optical gap. An algorithm for estimating these parameters is considered which ensures high-accuracy estimates under fairly weak requirements on the image quality of the test object. The estimate accuracy was calculated analytically and confirmed by simulation.

A method for classifying moving objects having a seismic impact on the ground surface is proposed based on the statistical analysis of the envelopes of received signals. The values of the components of the amplitude spectrum of the envelopes obtained by Hilbert and Fourier transformations are used as a criterion of classification. Examples illustrating the statistical properties of spectra and the operation of the seismic classifier are given for an ensemble of objects of four classes (person, group of people, large animal, car). It is shown that the computing procedures for processing seismic signals are quite simple and can be used in real-time systems with modest requirements to computational resources.

It is proposed to use weight coefficients of the bilateral filter to calculate the measure of similarity of image regions in optical flow calculation algorithms. The efficiency of using this measure is studied by an example of a three-dimensional recursive search algorithm. Weight coefficients are used for calculating the optical flow with subpixel accuracy by the Lucas -Kanade algorithm. A possibility of reducing the optical flow calculation error by means of using the proposed approaches is demonstrated by an example of processing of various types of images. A method of choosing the parameters of the weight functions of the bilateral filter is described and analyzed.

Frequency characteristics of the procedure of spline-smoothing of information coming in real time are obtained. A recurrent spline is studied from the standpoint of the theory of linear dynamical systems. The estimation of quality and sustainability of the recursive spline filter are described. The spline transformation laws identified in a frequency analysis are confirmed by the indicators of smoothing quality in the time domain.

A new method of loop closure based on storage of local maps of obstacles and meant for reducing an accumulated localization error is proposed. The advantage of this method in comparison with the earlier one is in reducing the amount of RAM. The testing results for the developed system and comparisons with analogues are presented.

This paper describes a method for estimating the location of a radiating target for a case of substantial prior uncertainty with respect to operating conditions of a triangulation measuring system. Comparative analysis results and practical recommendations on using the method are given.

The knowledge of optical and dielectrical properties of ferroelectric films, in particular, strontium-barium niobate films, in the terahertz spectral range is needed to use these films as a basis of active elements and structures for detection and control of terahertz radiation. The properties of strontium-barium niobate films with x = 0.5 grown on oriented sapphire substrates with an applied electrode are studied by the method of pulsed broad-band terahertz spectroscopy in the spectral range of 0.2-1.3 THz. It is found that strontium-barium niobate films can be used to develop devices for detection and control of terahertz radiation.

The growth of the natural oxide of the Cd_x Hg_{1 - x}Te (MCT) compound is studied by methods of laser and spectral ellipsometry. It is found that a non-absorbing oxide film is formed from the very beginning in the case of MCT oxidation with hydrogen peroxide vapors, whereas oxidation with atmospheric oxygen leads to the formation of absorbing layer on the surface at the first stages of the process. When the oxide film thickness reaches 1-2 nm, the oxidation rate drastically decreases. If MCT samples that were stored for a long time (for years) in air at room temperature are heated at T = 200 ºC, the optical thickness of the oxide film decreases.

A comparative analysis of the prospects of creating superthin, light, and highly efficiency solar cells based on A^IIIB^V/InGaAs and A^IIIB^V/Ge heterostructures is performed. Technological problems and prospects of each variant are discussed. A method of thinning of A^IIIB^V/Ge heterostructures with the use of an effective temporal technological carrier is proposed. The method the process to be performed almost with no risk of heterostructure fracture, thinning of the Ge cascade down to several tens of micrometers (or even several micrometers), significant increase in the percentage of good devices being produced, and also convenient and reliable transfer of thinned solar cells to an arbitrary light and flexible substrate. Such a technology offers a possibility of creating high-efficiency thin and light solar cells for space vehicles on the basis of batch-produced A^IIIB^V/Ge heterostructures.

Principal issues of using pyrometry for temperature monitoring is low-temperature processes in the technology of production of semiconductor structures are considered by an example of growing mercury-cadmium-telluride (MCT) layers on the GaAs substrate by the method of molecular beam epitaxy. Optical and thermophysical modes are proposed to describe the processes of radiant heat transfer in a vacuum chamber. Based on these models, it is demonstrated that radiation from the heater and the signal reflected from the chamber walls, which are comparable in magnitude with the measured radiation emitted by the sample, should be taken into account in interpreting data measured by a pyrometer. Methods of useful signal identification are found. Experiments on temperature measurement by a pyrometer mounted on the MCT growth chamber are performed. Results of these experiments are in good agreement with theoretical predictions.