Influence of Order of Double Step Implantation of 64Zn+ and 16O+ Ions into Si on Formation of Zinc-containing Nanoparticles

This paper presents the research the formation of zinc-containing nanoparticles (NPs) in Si (001) after double-step hot implantation of 64Zn+ and 16O+ ions. High-resolution Transmission Electron Microscopy (HRTEM) and X-ray Diffraction (XRD) methods were used to study a crystal structure of the samples. Depth profiles of implanted impurity atoms were measured by Secondary Ion Mass Spectrometry (SIMS). Zn NPs with a size of 3 up to 50 nm were found in the implanted samples. Zinc-containing NPs with the size of 5-10 nm were found in the surface layer of as-implanted Si substrates. The effect of the order of implantation on structural defects and the impurity atoms depth profiles is established

Influence of Order of Double Step Implantation of 64Zn+ and 16O+ Ions into Si on Formation of Zinc-containing Nanoparticles

This paper presents the research the formation of zinc-containing nanoparticles (NPs) in Si (001) after double-step hot implantation of 64Zn+ and 16O+ ions. High-resolution Transmission Electron Microscopy (HRTEM) and X-ray Diffraction (XRD) methods were used to study a crystal structure of the samples. Depth profiles of implanted impurity atoms were measured by Secondary Ion Mass Spectrometry (SIMS). Zn NPs with a size of 3 up to 50 nm were found in the implanted samples. Zinc-containing NPs with the size of 5-10 nm were found in the surface layer of as-implanted Si substrates. The effect of the order of implantation on structural defects and the impurity atoms depth profiles is established

Distribution of dislocations near the interface in AIN crystals grown on evaporated SiC substrates

To exploit unique properties of thin films of group III-nitride semiconductors, the production of native substrates is to be developed. The best choice would be AlN; however, presently available templates on sapphire or SiC substrates are defective. The quality of AlN could be improved by eliminating the substrate during the layer growth. In this paper, we demonstrate freestanding AlN layers fabricated by an SiC substrate evaporation method. Such layers were used to investigate dislocation structures near the former AlN?SiC interface. Specimens were characterized by synchrotron radiation imaging, triple-axis diffractometry and transmission electron microscopy (TEM). We found that the evaporation process under non-optimal conditions affected the dislocation structure. When the growth had been optimized, AlN layers showed a uniform distribution of dislocations. The dislocations tended to constitute low-angle subgrain boundaries, which produced out-of-plane and in-plane tilt angles of about 2?3 arc-min. Similar broadening was observed in both symmetric and asymmetric rocking curves, which proved the presence of edge, screws as well as mixed dislocation content. TEM revealed arrays of edge threading dislocations, but their predominance over the other threading dislocations was not supported by present study. To explain the experimental observations, a theoretical model of the dislocation structure formation is proposed. ? 2017 by the authors. Licensee MDPI, Basel, Switzerland.11Ysciescopu

Synthesis and Nanoscale Characterization of LiNbO3 Thin Films Deposited on Al2O3 Substrate by RF Magnetron Sputtering under Electric Field

LiNbO3 thin films were deposited on Al2O3 substrates by RF-magnetron sputtering with in-situ electric field to study the self-polarization effect. The films have been characterized crystallographically by x-ray diffraction, and morphologically by atomic force microscopy. The films contain crystallites of LiNbO3 with preferable orientation [012] along the normal to the Al2O3 substrate surface (012). Piezoresponse force microscopy was used to study vertical and lateral polarization direction in LiNbO3 thin films. The analysis of the histograms of vertical piezoresponse images allowed to reveal self-polarization effect in films. The local piezoelectric hysteresis performed on the nanometer scale indicates switching behavior of polarization for LiNbO3 thin film

Synthesis and Nanoscale Characterization of LiNbO3 Thin Films Deposited on Al2O3 Substrate by RF Magnetron Sputtering under Electric Field

LiNbO3 thin films were deposited on Al2O3 substrates by RF-magnetron sputtering with in-situ electric field to study the self-polarization effect. The films have been characterized crystallographically by x-ray diffraction, and morphologically by atomic force microscopy. The films contain crystallites of LiNbO3 with preferable orientation [012] along the normal to the Al2O3 substrate surface (012). Piezoresponse force microscopy was used to study vertical and lateral polarization direction in LiNbO3 thin films. The analysis of the histograms of vertical piezoresponse images allowed to reveal self-polarization effect in films. The local piezoelectric hysteresis performed on the nanometer scale indicates switching behavior of polarization for LiNbO3 thin film

Freestanding single crystal AlN layers grown using the SiC substrate evaporation method

The physical vapor transport growth of aluminium nitride (AlN) layers was performed in one process with the evaporation of silicon carbide (SiC) substrates. In this paper, we show that the rate of SiC evaporation is slow in a narrow process window for AlN growth but increases in the presence of AlN vapor. The properties of the substrates influence the evaporation process; therefore an investigation is done to understand this phenomenon. We first describe the evaporation behavior of a SiC substrate depending on its size, thickness, structure and polarity. Then we demonstrate the surface morphology and structural quality of the AlN layers grown on C-polar SiC. In the case of a step-flow growth, our method allows us to obtain thin freestanding layers with moderate dislocation densities and rocking curve widths comparable to those of bulk crystals. ? 2017 The Royal Society of Chemistry.11Nsciescopu

Thermal and lattice misfit stress relaxation in growing AIN crystal with simultaneous evaporation of SiC substrate

AlN single crystals were prevented from cracking by simultaneous growth and evaporation of SiC substrates. Freestanding layers (��1 mm thick) were proved continuous (non?cracked) and used as a model system to investigate the type of dislocation structure near AlN/SiC interface. Using x-ray diffraction techniques, we found that, unlike GaN films, in which high-density threading dislocations cross the film along its normal, the AlN layers possess a mosaic structure composed of low-angle subgrain boundaries. We suggest a theoretical model that describes the misfit stress relaxation in growing AlN crystal. ? 2017 Trans Tech Publications, Switzerland.11Nscopu

Microstructure and strength of AlN?SiC interface studied by synchrotron X-rays

Bulk AlN crystals grown by sublimation on SiC substrates exhibit relatively high dislocation densities. The kind of defect formation at early growth stages influences the structural quality of the grown crystals. In this work, the dislocation distribution near to the interface is understood through investigation of thin (��1.5?mm) continuous (non-cracked) freestanding crystals obtained in one process with the evaporation of the substrates. The AlN specimens were characterized using synchrotron radiation imaging techniques. We revealed by triple-axis X-ray diffraction study that, near to the former interface, randomly distributed dislocations configured to form boundaries between �� 0.02? misoriented sub-grains (from [0001] direction). Threading dislocation structure similar to that in epitaxial GaN films was not detected. To explain these observations, a theoretical model of misfit stress relaxation near the interface is suggested. ? 2016, Springer Science+Business Media New York.112sciescopu

Structural, electrical and luminescent characteristics of ultraviolet light emitting structures grown by hydride vapor phase epitaxy

Electrical and luminescent properties of near-UV light emitting diode structures (LEDs) prepared by hydride vapor phase epitaxy (HVPE) were studied. Variations in photoluminescence and electroluminescence efficiency observed for LEDs grown under nominally similar conditions could be attributed to the difference in the structural quality (dislocation density, density of dislocations agglomerates) of the GaN active layers, to the difference in strain relaxation achieved by growth of AlGaN/AlGaN superlattice and to the presence of current leakage channels in current confining AlGaN layers of the double heterostructure