The metal–silicon thin−film system is not isostructural and furthermore exhibits pronounced interdiffusion and chemical reactions. Therefore the growth of metallic films on silicon leads to a high concentration of defects in the film, especially at its substrate interface. The material also contains stress and a transition layer consisting of melts or compounds (silicides).
We have considered theoretical viewpoints and reviewed experimental data on the growth and properties of metallic nanofilms (including multilayered ones) on silicon, and also provided a brief review of their applications. The films consist either of atomic−sized, quabquantum sized and quantum sized layers. We have suggested a low temperature film growth technology based on freezing growing layers during deposition by maintaining a low temperature of the substrate and using an atomic beam with a reduced heat power. The technology uses a specially shaped deposition system in which the distance between the source and the substrate is comparable to their size or smaller. Furthermore, we use a special time sequence of deposition that provides for a reduced substrate surface temperature due to greater intervals between deposition pulses. This growth method of atomically thin films and multilayered nanofilms excludes interdiffusion between the layers, reduces three−dimensional growth rate and relatively increases lateral layer growth rate.
MATERIALS SCIENCE AND TECHNOLOGY. SEMICONDUCTORS
MATERIALS SCIENCE AND TECHNOLOGY. MAGNETIC MATERIALS
Promising absorbing materials along with Ni−Zn−ferrites are Mg—Zn−ferrites, as they are also intensively absorb electromagnetic waves in the frequency range from 50 MHz to 1000 MHz. The main advantage of the Mg−Zn−ferrite is that it is an inexpensive raw material magnesium oxide. The aim of this work was to study the effect of alloying elements — TiO2 and Bi2O3, — as well as impurities on the microstructure and properties of radar Mg—Zn−ferrite. The influence of alloying elements and impurities on the magnetic and dielectric constant of Mg—Zn−ferrite absorbing materials has been revealed. The addition of bismuth oxide causes a reduction of the permittivity and permeability Mg—Zn−ferrite in the range of up to 1000 MHz. Addition of titanium oxide increases the dielectric constant in the range of up to 1000 MHz, which is important to reduce the wavelength of radar ferrite materials. Addition of titanium oxide leads to a frequency shift of the absorption Mg—Zn−polycrystalline ferrite material towards lower frequencies, and bismuth — towards high frequencies.
Thus, the dopant can be regarded as a tool to regulate the wavelength range of the absorption of radar and ferrite materials.
MODELING OF PROCESSES AND MATERIALS
EPITAXIAL LAYERS AND MULTILAYERED COMPOSITIONS
ISSN 2413-6387 (Online)