Papers by Author: A.V. Mazanik

Abstract: In this work we have studied the in-depth distribution of copper deposited on the surface of the hydrogen pre-implanted Cz Si wafers depending on the conditions of their subsequent annealing. In the standard n-type 4.5 ∙cm Cz Si wafers different numbers of radiation defects were formed by hydrogen ion implantation with an energy of 100 keV (0.9 m projected range, Rp) for different fluences (11015, 11016, or 41016 at/cm2) at room temperature. Then a copper layer 50-nm thick was deposited on the sample surface by magnetron sputtering at temperatures 250 or 300 oC with subsequent annealing for 4 h at the same temperatures. Whereupon the surface was chemically etched and the samples were annealed in vacuum during 2 h at 700 oC. The depth profiles of copper in the near-surface layer were controlled by RBS investigations both in the random and channeling modes. These experiments have shown that the copper in-depth distribution strongly depends on the implantation fluence and temperature of the low-temperature annealing: in case of copper deposition at 250 oC a relatively strong peak determined by copper on the surface is observed in RBS spectra after all the above-described steps. On the contrary, for higher temperatures of copper deposition (300 oC) a significant decrease in the intensity of this peak is observed in RBS spectra. A maximal concentration of copper at a depth of the projected range, Rp, was observed for the samples implanted with a maximal fluence (41016 at/cm2).

Abstract: Standard p-type 12 cm Cz Si wafers were implanted by helium ions. The implanted and nonimplanted samples were subsequently subjected to nitrogen plasma treatment and final vacuum annealing. SEM studies have shown the absence of large-scale defects on the top wafer surface and the presence of a layer revealing contrast with surrounding silicon on the cleavage surface at a depth corresponding to the projected range Rp. Scanning over a crater formed by ion sputtering has exposed no defects to the depth of Rp and beyond. At the same time, at a depth of Rp there is a layer with the morphology (structure) significantly different from the surrounding defect-free areas. The measurements of transverse conductivity have shown that the wafer with the formed nitrogen-contained layer possesses dielectric properties with a breakdown voltage up to 15 V.

Abstract: The main goal of this work is to investigate the influence of low-temperature argon ionbeam treatment on the electric and structural properties of a near-surface region of the standard commercial p-type Cz Si wafers, and to compare the effects of Ar+ and H+ ion-beam treatment. The measurements of thermo-EMF have shown that both Ar+ and H+ ion-beam treatment with the ion energy 200 eV and current density 0.15 mA/cm2 at a temperature of 30 oC during 30 min leads to the p-to-n −type overcompensation of the near-surface layer of silicon wafers. The measurements of photovoltage spectra have shown that (i) Ar+ and H+ treatments in like manner lead to the appearance of a photovoltage signal over a wide spectral region due to the formation of p-n-junction on the treated surface, and (ii) photosensitivity of the Ar+ ion-beam treated wafers in the ultraviolet (UV) spectral region (200-400 nm) is much greater as compared to the wafers subjected to H+ ion beam treatment in the same conditions. The main difference in the Ar+ and H+ ion-beam treatment effects is the formation of a thin (5-20 nm) oxygen-containing dielectric layer on the surface of hydrogenated samples and the absence of such layer in case of Ar+ ion-beam treatment.

Abstract: The main goal of this work is to demonstrate the correlation between the density and type of surface defects arising during the formation of a buried nitrogen-containing layer in Si wafers, and the number of buried defects formed by different dose hydrogen preimplantation. Standard commercial 12 ⋅cm boron-doped and 4.5 ⋅cm phosphorous-doped Cz Si wafers were subjected to hydrogen ion implantation at room temperature with the energy 100 keV and doses 1⋅1015 - 4⋅1016 at/cm2. Then nitrogen was introduced into silicon from a DC plasma source at a temperature of 300 oС. Finally, all samples were subjected to 2 h vacuum annealing at 900 oС. The experiments have shown that the density and type of the surface defects depend significantly on the dose of hydrogen implantation, parameters of N+-plasma treatment, and conductivity type of silicon. Optimization of the above-mentioned parameters makes it possible to create the substrates containing a buried dielectric SixNy layer and having a practically defect-free surface.

Abstract: Transformation of the “core” atomic structure and electronic states of the tilt Σ5 θ = 37° [001]/(130) grain boundary in poly-Si due to incorporation of carbon atoms into the oxygencontaining complexes is studied using MM and MO LCAO methods. Different numbers n = 1 ÷ 4 of C-atoms were introduced into the 5-fold interstitial positions in the initial O-containing complexes built-up from SiO3 and SiO4 configurations at the GB “core”. Incorporation of C-atoms into SiO3 and SiO4 complexes leads to the formation of Si-O-C-Si chains and shifting of the donorlike levels generated by SiO3 and SiO4 configurations to the bottom of the conduction band with an increase in the number of the incorporated C-atoms.

Abstract: The radiation defects in 10 Ω⋅cm p-type and 4.5 Ω⋅cm n-type Cz Si were created at depth of 0.8-1 µm using 100 keV 2⋅1016 at/cm2 hydrogen implantation at room temperature. Then the introduction of nitrogen into silicon and its diffusion were carried out at different thermodynamic conditions. Finally, the samples were vacuum annealed at 800 oС during 2 h. The state of sample surfaces was studied by SEM. The depth and thickness of SixNy layer and also defect numbers were estimated by RBS method in the channeling mode. The electrical properties of the obtained structures were characterized by the transversal conductance measurements with the keep of a standard LCR-meter at a frequency of 1 MHz using the two-probe method. Our experiments have shown that the above-described method enables one to form the buried SiхNy layer with dielectric properties and the number of defects and nitrogen atoms on the silicon surface and in the near-surface region are comparable with those for the initial silicon wafers.

Abstract: The paper presents the study of CdS0.2Se0.8 n-type films 0.50-0.65 µm thick manufactured by the RF sputtering technique and their electro-optical properties. The effects of the substrate texturing on the structure and properties of the films are discussed. Recrystallization of the films sputtered onto glass substrates coated with a continuous or island-like silver sublayer resulted in the formation of a nanosized grain structure with higher photosensivity than films deposited onto aluminium oxide ceramics.