LOW-TEMPERATURE ION-PLASMA DEPOSITION TECHNOLOGY OF NANOSTRUCTURED FILMS OF ALUMINUM AND BORON NITRIDES

2021 ◽  
Vol 56 ◽  
pp. 97-107
Author(s):  
M. S. Zayats ◽  

A low-temperature (substrate heating temperature up to 400 °C) ion-plasma technology for the formation of nanostructured AlN and BN films by the method of high-frequency reactive magnetron sputtering of the corresponding targets has been developed (the modernized installation "Cathode-1M"), which has in its technological cycle the means of physical and chemical modification, which allow to purposefully control the phase composition, surface morphology, size and texture of nanocrystalline films. The possibility of using the method of high-frequency magnetron sputtering for deposition of transparent hexagonal BN films in the nanoscale state on quartz and silicon substrates is shown. Atomic force microscopy (AFM) has shown that AlN films can have an amorphous or polycrystalline surface with grain sizes of approximately 20-100 nm, with the height of the nanoparticles varying from 3 to 10 nm and the degree of surface roughness from 1 to 10 nm. It was found that the dielectric penetration of polycrystalline AlN films decreases from 10 to 3.5 at increased frequencies from 25 Hz to 1 MHz, and the peak tangent of the dielectric loss angle reaches 0.2 at 10 kHz. Such features indicate the existence of spontaneous polarization of dipoles in the obtained AlN films. Interest in dielectric properties in AlN / Si structures it is also due to the fact that there are point defects, such as nitrogen vacancies and silicon atoms, which diffuse from the silicon substrate during synthesis and play an important role in the dielectric properties of AlN during the formation of dipoles. The technology makes it possible, in a single technological cycle, to produce multilayer structures modified for specific functional tasks with specified characteristics necessary for the manufacture of modern electronics, optoelectronics and sensorics devices. It should also be noted that the technology of magnetron sputtering (installation "Cathode-1M") is highly productive, energetically efficient and environmentally friendly in comparison with other known technologies for creating semiconductor structures and allows them to be obtained with minimal changes in the technological cycle.

2008 ◽  
Vol 15 (01n02) ◽  
pp. 23-27
Author(s):  
XIULI CHEN ◽  
HUIQING FAN

The relaxor ferroelectric Pb ( Mg 1/3 Nb 2/3) O 3– PbTiO 3 compositions are of interest owing to their excellent dielectric, electromechanical, electro-optical, and other properties. In this paper, the 0.80 Pb ( Mg 1/3 Nb 2/3) O 3–0.20 PbTiO 3 (PMN–PT 80/20) films with pure perovskite structure were synthesized by a single step at 150°C. The corresponding oxides were used as starting materials, namely PbO , MgO , Nb 2 O 5, and TiO 2. By using oxides as precursors, we simplified the hydrothermal process, allowing the process to be more economical. The influences of the Ti metal substrate on the PMN–PT 80/20 films are investigated. By surveying the variations of films, it was suggested that the substrate reacted with the ions in the solution. The films were smooth and homogeneous. There were no cracks and abnormity crystals on the surface of the films. The thickness was about 20 μm. The frequencies dependence of the dielectric properties of PMN–PT 80/20 films was stable even at a high frequency range over 1 MHz.


2019 ◽  
Vol 23 (3) ◽  
pp. 746-754
Author(s):  
Dinar Dilshatovich Fazullin ◽  
Gennady Vitalievich Mavrin ◽  
Vladislav Olegovich Dryakhlov ◽  
Ildar Gilmanovich Shaikhiev ◽  
Irek Rashatovich Nizameyev

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4017
Author(s):  
Dorota Szwagierczak ◽  
Beata Synkiewicz-Musialska ◽  
Jan Kulawik ◽  
Norbert Pałka

New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1–6.7 and low dielectric loss in the frequency range 0.14–0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900–960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.


2021 ◽  
Vol 13 (7) ◽  
pp. 3617
Author(s):  
Agnieszka Medyńska-Juraszek ◽  
Agnieszka Latawiec ◽  
Jolanta Królczyk ◽  
Adam Bogacz ◽  
Dorota Kawałko ◽  
...  

Biochar application is reported as a method for improving physical and chemical soil properties, with a still questionable impact on the crop yields and quality. Plant productivity can be affected by biochar properties and soil conditions. High efficiency of biochar application was reported many times for plant cultivation in tropical and arid climates; however, the knowledge of how the biochar affects soils in temperate climate zones exhibiting different properties is still limited. Therefore, a three-year-long field experiment was conducted on a loamy Haplic Luvisol, a common arable soil in Central Europe, to extend the laboratory-scale experiments on biochar effectiveness. A low-temperature pinewood biochar was applied at the rate of 50 t h−1, and maize was selected as a tested crop. Biochar application did not significantly impact the chemical soil properties and fertility of tested soil. However, biochar improved soil physical properties and water retention, reducing plant water stress during hot dry summers, and thus resulting in better maize growth and higher yields. Limited influence of the low-temperature biochar on soil properties suggests the crucial importance of biochar-production technology and biochar properties on the effectiveness and validity of its application in agriculture.


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