Влияние параметров слоя кремний-германиевой базы на эффект саморазогрева в структуре гетеропереходного биполярного транзистора
An electro-thermal modeling of modern SiGe and Si bipolar transistor structures using TCAD Sentaurus Synopsys has been carried out. It has been shown that for SiGe heterojunction bipolar transistors, operating at high current density, the internal temperature is higher than for identical Si transistors. As a result a stronger degradation of the device parameters and electrical characteristics is observed.
System for thermal design on chip- and board-level of electronic components is introduced. It is integrated with Mentor Graphics CAD and consists of three subsystems: thermal design in IC Station; thermal design in Expedition PCB; thermal measurement for verification of temperature modeling results.
Automatic electro-thermal analysis is included into Mentor Graphics PCB Design System. New software tool named TransPower is introduced to couple the electrical (Analog Designer) and thermal (BETAsoft) simulators. The design procedure is fully automated, human errors are eliminated, simulation time is significantly decreased, while accuracy and reliability are increased.
An overview is given of published papers on investigations of ionizing radiation influence (gamma, neutron, and proton) on characteristics of silicon-germanium heterojunction transistors -- elements of SiGe BiCMOS integrated circuits of 4 generations with design rules 0.25, 0.18, 0.13, and 0.09 um. Experimental data are explained on the basis of modern understanding of radiation effects in bipolar junction transistors with proper consideration of silicon-geramnium heterostructure properties. It is shown that major SiGe HBT parameters (beta, gm, VA, fT, fmax etc.) are less succeptible to radiation influence unlike silicon transistors. In total absorbed dose, SiGe HBTs feature unique hardness, that is 50-100 Mrads for the latest SiGe technology.
The effects of proton irradiation on SiGe heterojunction bipolar transistor (HBT) are investigated using Synopsys/ISE TCAD tool. To account for the impact of proton irradiation models for carrier lifetime degradation under irradiation are included in the program. The results of modeling the impact of protons of different energies are presented. For SiGe HBT increase in the base current for low-energy protons is more intense than for high-energy protons. We also present the simulation results of SiGe HBT dc and ac performance after proton exposure. The simulation results are in good agreement with experimental data.
The physical, mechanical and thermal properties of polyurethane produced by the reaction of urethane prepolymers with coordination compounds of copper were studied. The peculiarity of the used metal complexes is catalytic activity in the low-temperature dissociation of urethane groups and the ability to interact with the isocyanate groups with the subsequent formation of azoaromatic derivatives. It was found that when urethane prepolymers interacted with the bulky coordination compounds of copper the rigid blocks of coordination-related azo groups were formed which had a significant influence on the supramolecular organization of polyurethanes, and the complex of their physical and mechanical properties. It was shown that the metal complex structuring did not lead to a deterioration of the thermal stability of polyurethanes.The physical, mechanical and thermal properties of polyurethane produced by the reaction of urethane prepolymers with coordination compounds of copper were studied. The peculiarity of the used metal complexes is catalytic activity in the low-temperature dissociation of urethane groups and the ability to interact with the isocyanate groups with the subsequent formation of azoaromatic derivatives. It was found that when urethane prepolymers interacted with the bulky coordination compounds of copper the rigid blocks of coordination-related azo groups were formed which had a significant influence on the supramolecular organization of polyurethanes, and the complex of their physical and mechanical properties. It was shown that the metal complex structuring did not lead to a deterioration of the thermal stability of polyurethanes.
In article technique of application of the system ASONIKA in modeling of thermal processes of units and printed circuit boards is presented. Also in article an example of calculation of the unit and printed circuit board for thermal effects under steady-state and no steady-state modes in according to the technique described in the system ASONIKA is presented.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
Many electronic devices operate in a cyclic mode. This should be considered when forecastingreliability indicators at the design stage.The accuracy of the prediction and the planning for the event to ensure reliability depends on correctness of valuation and accounting greatest possiblenumber of factors. That in turn will affect the overall progress of the design and, in the end,result in the quality and competitiveness of products
Let G be a semisimple algebraic group whose decomposition into the product of simple components does not contain simple groups of type A, and P⊆G be a parabolic subgroup. Extending the results of Popov , we enumerate all triples (G, P, n) such that (a) there exists an open G-orbit on the multiple flag variety G/P × G/P × . . . × G/P (n factors), (b) the number of G-orbits on the multiple flag variety is finite.
I give the explicit formula for the (set-theoretical) system of Resultants of m+1 homogeneous polynomials in n+1 variables