Charge Effects in the Dielectric Films of MIS Structures under the Concurrent Influence of Radiation and High-Field Electron Injection
Based on the obtained experimental data, a model is developed for the processes of a variation in the charge state of MIS (metal–insulator–semiconductor) structures under the concurrent influence of high-field tunneling electron injection and radiation. The model takes into account the interaction between injected electrons and charges appearing in the dielectric film due to radiation and high-field ionization. It is shown that some holes may be annihilated during the interaction between injected electrons and holes trapped in a SiO2 film, thus leading to the formation of surface states at the interface with silicon. The effect of the electric-field intensity and injection current density on the generation and annihilation of positive charge and the formation of surface states under radiation is studied. The effect of charge processes occurring in the insulator film of a MIS structure under the concurrent action of radiation and high-field electron injection on a change in the threshold voltage of MIS devices and radiation sensors based on them is considered.
Methods of modication of gate dielectrics of the MOS structures by high-field electron injection and arc plasma jet treatment were studied. It is possible to use them for correction of parameters, decreasing defects number and increasing reliability of MOS devices. It was found that the negative charge accumulated in the film of the phosphorus-silicate glass of the MOS structures with the two-layer gate dielectric SiO2phosphorus-silicate glass under the high-field electron injection can be used for modication of devices with the same structures. It is shown that the injection-thermal treatment allows to find and exclude MOS structures with defects of isolation and charge defects. Arc plasma jet treatment was found to improve characteristics of the MOS devices. These treatments increase injection and radiation resistance of the gate dielectric by creating the needed density of electron traps in the bulk of SiO2 film.
In this paper we have shown a construction of an active sensitive element of irradiation sensor. This sensor is based on metal-insulator-semiconductor structures (MIS structures). In this work we have researched an influence of α-particles to the MIS structures, which were in the mode of the constant current maintaining. This mode is characterized by the high-field Fowler- Nordheim injection. We have shown that ionization processes occurring in dielectric films of MIS structures, which are in the mode of charging and discharging of capacitance and also in the mode of high-field tunnel injection of electrons by pulse of constant current, could be used in order to register the irradiation. We have found out advantages and disadvantages of utilization of MIS sensors to register charged particles. We also have advised how to use these layers.
The paper considers an influence of different kinds of radio-frequency plasma treatments onto modification of MIS structures with a thermal SiO2 film which is aimed at improvement of electro-physical parameters of the film. It was found that for the modification of MIS structures it is more preferable to utilize the oxygen plasma radio-frequency plasma treatment performed by a setup with the parallel-plate-type reactor. This is due to the fact that setup allows to have lesser degradation of charge characteristics of the gate dielectric in comparison with a setup with the cylindrical quartz reactor. The radio-frequency plasma treatment stimulates restructuring of SiO2 film and, as a result, diminishes possibility of sample breakdown and raises injection and radiation stability of the samples.
Mechanical performances of titanium biomedical implants manufactured by superplastic forming are strongly related to the process parameters: the thickness distribution along the formed sheet has a key role in the evaluation of post-forming characteristics of the prosthesis. In this work, a finite element model able to reliably predict the thickness distribution after the superplastic forming operation was developed and validated in a case study. The material model was built for the investigated titanium alloy (Ti6Al4V-ELI) upon results achieved through free inflation tests in different pressure regimes. Thus, a strain and strain rate dependent material behaviour was implemented in the numerical model. It was found that, especially for relatively low strain rates, the strain rate sensitivity index of the investigated titanium alloy significantly decreases during the deformation process. Results on the case study highlighted that the strain rate has a strong influence on the thickness profile, both on its minimum value and on the position in which such a minimum is found.
The ХХV International scientific – technical conference “Foundry 2018” was held of the 18-20 April 2018 at “Rostov” hotel in the city of Pleven, Bulgaria. Its aim is to provide a meeting place for scholars from different countries to present their scientific achievements and to discuss the problems of casting production.
The structural and spectroscopic features of the EuAl3(BO3)4 individual skeletal microcrystals synthesized by a melt solution method have been studied. Their infrared spectra taken from the as-grown microcrystal surfaces mainly contain the lines of the rhombohedral modification of EuAl3(BO3)4 and additional peaks of its monoclinic modification. TEM and X-ray diffraction studies confirm that these additional peaks in the IR spectra belong to the monoclinic C2/c polytype of the EuAl3(BO3)4 compound. We are the first to demonstrate the presence of coherent monoclinic domains in rhombohedral EuAl3(BO3)4 crystals by TEM. Cathodoluminance spectroscopy shows that the microcrystals generate strong emission lines in the range 580–630 nm, and their intensities are strongly influenced by the crystal orientation.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.