Interface layers at insulator contacts with a semiconductor and metallic electrode produce inhomogeneous potential and external voltage distributions in the gap between a substrate and a gate regardless of a material used (a silicon oxide, high-k dielectrics, or ferroelectrics). Considering the resulting inhomogeneity of the permittivity distribution across a thin insulating layer, mathematical apparatus for restoring the actual potential profile in the gap between a substrate and a gate from experimental tunneling I-V characteristics of metal-insulator-semiconductor (MIS) structures was developed. Depending on the proximity of maximum field voltages used in the experiment to the potential barrier elimination voltage, the criteria for constructing the actual potential versus coordinate dependence along the normal to the film plane were formulated. Approaches for the computation of model potential profiles and permittivity distributions parameters in insulating layers providing for the best fit between theoretically calculated tunneling conductivity results and experimental data were proposed.

Polycrystalline thin films ofstrontium bismuth tantalate SryBi2 + xTa2O9 with different Sr : Bi : Ta molar ratios are obtained by a sol–gel method. The formation of a phase with a perovskite structure is established. Phase transitions are confirmed by dielectric spectroscopy. In the mode of polarization switching spectroscopy, remnant piezoelectric hysteresis loops are obtained which confirm the ferroelectric nature of the synthesized SryBi2 + xTa2O9 films.

Polycrystalline thin films of bismuth-strontium tantalum SryBi2+xTa2O9 with different molar ratio Sr:Bi:Ta were obtained by sol-gel method. The formation of a phase with a perovskite structure has been established. Phase transitions have been confirmed by dielectric spectroscopy. In the mode of polarization switching spectroscopy, remnant piezoelectric hysteresis loops were obtained, which confirms the ferroelectric nature of the synthesized SryBi2+xTa2O9 films.

The influence of various parameters, such as annealing temperature and Nb content, on the structure and piezoelectric properties of thin-film structures based on the SBTN sol-gel layer are determined. The values of piezoresponse were investigated, and experiments on local polarization switching were carried out. Dependencies of the piezoelectric coefficients on the composition of the SBTN layer and the parameters of the sol-gel process were established.

The shape of high-frequency capacitance-voltage characteristics of structures with an insulating layer replacing silicon oxide is considered. It is shown that the buffer layer interaction on the interface with silicon substrates is related to the shielding of external electric fields by charges of the electron traps. It is found that the presence of two plateaus in the high-frequency capacitance-voltage characteristics does not necessarily indicate deep depletion and strong enrichment of a semiconductor. The presence of both capacitive plateaus in the case of strong screening can be explained by the pinning of the Fermi level of Si on electron traps of the buffer layer with a high concentration and a U-shaped spectrum. An algorithm is formulated for calculating the band bending in a semiconductor from the minimal values of the high-frequency capacitance of a sample in the region of depletion effects on the substrate. The theoretical construction was used for determining the characteristics of a structure with an insulating HfO2 layer and it was shown that in this case the buffer layer almost completely shields external electric fields, which prevents significant band bending in the silicon substrate.

Films of hafnium oxide (HfO2) were synthesized on a silicon substrate by magnetron sputtering of a target with a similar composition. The results of studies of the structural composition of HfO2 films and the electrical properties of metal-insulator-semiconductor (Ni-HfO2-n-Si) structures are presented.

Ferroelectric films of the composition Ba 0.8 Sr 0.2 TiO 3 (BST) were synthesized on platinized silicon substrates by RF sputtering. Top electrodes made of nickel, aluminum, copper and chromium were formed on the grown films by electron beam sputtering. The results of studies of the electrophysical properties of the obtained metal-dielectric-metal (MDM) heterostructures (Me-BST-Pt-Si) are presented. Keywords: ferroelectric BST films, metal-dielectric-metal (MDM) structures, microstructure, electrophysical properties.

Sol-gel films BaxSrl-xTi03 (x = 0,8; 0, 9; 1) were obtained, the dependences of their properties on the parameters of the sol-gel process were determined. The research results allow us to propose ferroelectric structures for use in DRAM devicesof thin sol-gel films.

Hafnium oxide (HfO 2 ) films are synthesized on silicon substrates using magnetron sputtering under various technological conditions. The results on the structural composition of HfO 2 films and the electrical properties of metal–insulator–semiconductor heterostructures (Ni– HfO 2 –Si) based on them are presented.

Сегнетоэлектрические пленки состава Ba0.8Sr0.2TiO3 (BST) синтезированы на платинированные кремниевые подложки методом ВЧ-распыления. На выращенные пленки методом электронно-лучевого распыления сформированы верхние электроды из никеля, алюминия, меди и хрома. Представлены результаты исследований электрофизических свойств полученных гетероструктур металл--диэлектрик--металл (МДМ) (Ме-BST-Pt-Si). Ключевые слова: сегнетоэлектрические пленки BST, структуры металл--диэлектрик--металл (МДМ), микроструктура, электрофизические свойства.

Hafnium oxide (HfO_2) films were synthesized onto silicon substrates by magnetron sputtering under various technological conditions. Research results presented structural composition of HfO2 films and electrical properties of heterostructures metal-insulator-semiconductor (Ni–HfO_2–Si) based on them.

Films of hafnium oxide (HfO2) were synthesized on a silicon substrate by magnetron sputtering of a target with a similar composition. The results of studies of the structural composition of HfO2 films and the electrical properties of metal-insulator-semiconductor (Ni-HfO_2-n-Si) structures are presented Keywords: Metal-dielectric-semiconductor (MDS) structures, hafnium oxide (HfO2) ferroelectric films, piezoelectric response, microstructure, electrical properties.

Manifestation of the Franz–Keldysh effect was found under indirect daylight illumination of Al‒n+-Si:P–SiO2–(100) n-Si with ultrafine (3.7 nm) oxide. It is shown that the use of illumination even at low field voltages (up to 3 V) leads to an increase in the tunneling current through the oxide compared to the current in darkness by three orders of magnitude. A model is constructed for the influence of radiation on the process of electron tunneling through an ultrathin insulating layer. First, as a result of the Franz–Keldysh effect, a radiation quantum is captured by an electron and a given charge carrier tunnels through the barrier at a higher level compared to darkness. After a charge carrier enters a semiconductor, its energy is sufficient for several acts of electron–hole pair production during the impact ionization of silicon.

High-frequency measurements of the capacitance and conductivity of Ni-Ba0.8Sr0.2TiO_3-Pt and Ni-Ba0.8Sr0.2TiO_3-Si objects with a ferroelectric thickness of 120 nm in the paraelectric phase were carried out. It is shown that in the entire range of external voltages, the electric field practically does not penetrate Si. The conclusion made earlier about the reasons for the weak manifestation of the field effect is confirmed --- the polarization of the ferroelectric layer is almost completely shielded by the charges of electronic traps at the Ba0.8Sr0.2TiO_3-Si contact. It is noted that a sharp decrease due to passivation of the activity of surface traps will allow implementing transistors based on metal-BST-Si structures with a working surface channel of non-basic charge carriers and will ensure the construction of high-quality FeRAM non-volatile memory cells. Keywords: metal-dielectric-semiconductor-structures, metal-dielectric-metal-structures, ferroelectric films of the composition Ba0.8Sr0.2TiO3, high-frequency impedance.

It is shown that microstructure, dielectric and piezoelectric properties change in films based on lanthanum-substituted bismuth titanate (BLT) depending on the alloying impurity material, which leads to changes in coercive voltage, internal displacement field and control coefficient. Keywords: lead-free ferroelectric films, bismuth titanate, electrophysical properties, capacitance-voltage characteristics, piezoresponse force microscopy.

Studies have been carried out on the effect of heating and a strong field, but pre-breakdown, effects on high-frequency characteristics of the impedance of heteroepitaxial structures Ni-Ba0.8Sr0.2TiO3-pSi with a ferroelectric thickness of 50 nm. It was shown, that regardless of the polarity of the field stress, characteristics shifted towards a positive bias, and the width of hysteresis loops decreased; plateau levels remained virtually unchanged. Heating up to 121oC led to a change in levels of the upper plateau of characteristics: for the capacity it decreased, and for the conductivity it increased; branches on the loop not only narrowed and shifted, but changed places in comparison with the original dependence (loop reverse). These results can be explained: under the field action, by the generation of additional electronic states, localized in the buffer layer at the Si-Ba1-xSrxTiO3 interface, and by heating, by the appearance of delay effects due to the development of fluctuation processes, underlying the smearing of the phase transition from ferroelectric to paraelectric condition. Keywords: High-frequency field characteristics of the impedance, the field stress, hysteresis loops, the generation of additional localized electronic states, delay effects, fluctuation processes, smearing of the phase transition.

Films of the composition Ba0.8Sr0.2TiO3 (BST) were synthesized by the method of high-frequency (HF) sputtering on the buffer layer of a ferroelectric film of the composition PbZrxTi1-xO3 (PZT). Comparative results of electrophysical properties of three different metal--dielectric--metal (MDM)-structures are presented: Pt/BST/Ni, Pt/PZT/Ni, and Pt/PZT-BST/Ni. Keywords: metal--dielectric--metal structures, ferroelectric films of composition Ba0.8Sr0.2TiO3, a buffer layer, electrophysical properties.

Проведена модернизация развитого ранее метода восстановления рельефа изолирующего потенциала, создаваемого сверхтонким слоем окисла кремния, из полевых зависимостей туннельного тока. Рассчитаны параметры трапецеидального модельного потенциала, обеспечивающие максимально близкую к экспериментальной зависимость производной логарифма тока по напряжению. Изменен подход к запуску процедуры последовательных итераций потенциала --- вместо обнуления в нулевом приближении значений координаты первой точки поворота использованы функции, вычисляемые из модельной формы. Модернизированный алгоритм применен к экспериментальным полевым зависимостям тока в структурах n+-Si-SiO2-n-Si с толщиной окисла 3.7 нм, обладающих ярко выраженной асимметрией туннельных вольт-амперных характеристик по отношению к полярности внешнего напряжения. Восстановленный из экспериментальных данных эффективный потенциальный барьер всегда существенно тоньше изолирующего слоя, его максимум смещен к контакту с поликристаллическим материалом, а эффективная масса туннелирующего электрона в разы больше типичного для толстого окисла кремния значения. Ключевые слова: вырожденный поликремний--окисел кремния--кремний, сверхтонкий окисел, туннельные вольт-амперные характеристики, изолирующий потенциальный рельеф.

Results of studies of ultrathin silicon oxide (37 Å)–polysilicon structures as prospects of substrates for objects with ferroelectric insulating layers are presented. It turned out that in structures with SiO 2 obtained by high-temperature oxidation, there are low leakage currents associated with tunneling conduction, and the concentration of localized electronic states is three orders of magnitude lower than in objects with native oxide. These circumstances open prospects of creating ferroelectric FeRAM non-volatile memory cells operating on such silicon oxide.