Силовые полупроводниковые приборы (СПП) на основе карбида кремния являются перспективной электронной компонентной базой для силовой электроники и импульсной техники. Технический уровень СПП оказывает существенное влияние на темпы роста важнейших отраслей экономики России.

Силовые полупроводниковые приборы (СПП) на основе карбида кремния являются перспективной электронной компонентной базой для силовой электроники и импульсной техники. Технический уровень СПП оказывает существенное влияние на темпы роста важнейших отраслей экономики России.

Рассмотрены вопросы, связанные с надежностью силовых 4H-SiC диодов Шоттки при кратковременных электрических перегрузках в обратном направлении (при работе диодов в импульсном лавинном режиме). В частности, обсуждается влияние неоднородности лавинного пробоя по площади диода на величину максимальной лавинной энергии (МЛЭ), которая может быть рассеяна диодом до того, как в нем произойдет вторичный тепловой пробой. Для оценки того, насколько однороден лавинный пробой, предложено сравнивать измеренную импульсную обратную вольт-амперную характеристику (ВАХ) диода с расчетной ВАХ идеального квазиодномерного диода. Проведены измерения обратных ВАХ промышленных 4H-SiC ДШ: через диоды пропускались одиночные импульсы лавинного тока длительностью ~1 μs; в процессе измерений амплитуда импульсов поднималась до величин, при которых происходил катастрофический отказ диодов. Показано, что увеличенное дифференциальное сопротивление диодов на лавинном участке ВАХ и пониженное экстраполированное напряжение пробоя (по сравнению с их расчетными значениями для идеальных диодов) предсказывают снижение величины МЛЭ. Ключевые слова: карбид кремния, диод Шоттки, лавинный пробой, надежность.

Силовые полупроводниковые приборы (СПП) являются основной электронной компонентной базой для мощной силовой электроники и импульсной техники, для важнейших областей экономики России. Состояние производства СПП оказывает существенное влияние на темпы роста экономики России и ее экономическую безопасность. Power semiconductor devices (PSD) are basic components for the electric power converting electronics and pulsed technology, for the most important branches of the Russian economy. The state-of-the-art in the development and production of PSD has a significant impact on the growth rate of the economy of Russia and its economic security.

We consider problems associated with the reliability of high-power 4 H -SiC Schottky diodes (SDs) during short-term electric overloads in the reverse direction (for diodes operating in the pulsed avalanche regime). In particular, we analyze the effect of nonuniformity of an avalanche breakdown over the diode area on the maximal avalanche energy (MAE) that can be dissipated by the diode prior to its secondary thermal breakdown. For estimating the uniformity of an avalanche breakdown, we propose that the measured pulse reverse current–voltage ( I – V ) characteristic of the diode be compared with the calculated I – V characteristic of an ideal quasi-one-dimensional diode. We measured reverse I – V characteristics of commercial 4 H -SiC SDs: single avalanche current pulses with a duration of ~1 μs were passed through the diodes; during measurements, the pulse amplitudes grew to values for which a catastrophic failure of diodes occurred. It is shown that an increase in the differential resistance of diodes on the avalanche segment of the I – V curve and a decrease in the extrapolated breakdown voltage (as compared to values calculated for ideal diodes) can lead to a decrease in the MAE.

AbstractWe report on the results of experimental investigation and numerical simulation of switching of SOS diode with p ^+ P _0 n ^+ structure and with reduced thickness of P _0-base. The proposed 1D diffusion-drift model of electron–hole plasma dynamics is found to be in good agreement with the experiment. The reduction of the P _0-base thickness has allowed us to double the output pulse voltage with the same switching current density. This has been reached by a considerable reduction of switching losses as well as due to the formation of the domain of a strong quasi-rectangular electric field at the P _0 n ^+ junction during the current interruption. As a result, output pulse amplitude considerably exceeds the static breakdown voltage of P _0 n ^+ junction. This effect has been observed for the first time for high-voltage semiconductor opening switches.

The results of studying the turn-off process of an integrated thyristor chip with dimensions of 13.5 × 13.5 mm, ~1 cm2 working area, and 2.5 kV blocking voltage, which was recently developed at VZPP-Micron, are presented. The thyristor was tested in a power circuit with an inductive load and switched-off by a gate current pulse with an amplitude equal to the power current. To reduce the inductance of the gate turn-off circuit, the switch-off pulse current former is located directly near the thyristor chip. Tests have shown that at 1200 V operating voltage, damage of the thyristor during turn-off process occurs at 107 A power current due to the electrons injection from the emitter junction into the region of the collector space charge. To eliminate this effect and increase the maximum switchable current, it is necessary to increase the rise rate of the turn-off current pulse in the gate electrode circuit.

Experimental observation and numerical simulations of sub-nanosecond avalanche switching of Si and ZnSe bulk semiconductor structures initiated by high-voltage pulses with steep (dU / dt > 10 kV/ns) ramp are reported. The measured switching time is ~100ps. The switching is sustainable and repetitive and has negligible jitter. Comparison of the experimental and numerical results suggests that after switching, the whole volume of the structure is uniformly filled with nonequilibrium electron-hole plasma.

We report on the results of experimental investigation and numerical simulation of switching of SOS diode with p + P 0 n + structure and with reduced thickness of P 0 -base. The proposed 1D diffusion-drift model of electron–hole plasma dynamics is found to be in good agreement with the experiment. The reduction of the P 0 -base thickness has allowed us to double the output pulse voltage with the same switching current density. This has been reached by a considerable reduction of switching losses as well as due to the formation of the domain of a strong quasi-rectangular electric field at the P 0 n + junction during the current interruption. As a result, output pulse amplitude considerably exceeds the static breakdown voltage of P 0 n + junction. This effect has been observed for the first time for high-voltage semiconductor opening switches.

Lagarkov, an outstanding Russian scientist and science organizer, professor, academician of the Russian Academy of Sciences (RAS), research supervisor of the Institute of Theoretical and Applied Electrodynamics of RAS (ITAE RAS). A N Lagarkov is a world-famous scientist. He is the author of more than three hundred scientific papers, four monographs, and a number of patents for inventions in the fields of plasma physics, electrophysics, and electrodynamics. Hewas elected a correspondingmember of RAS in 2000 and a full member in 2011. At the present time, he is a member of RAS Presidium and Bureau of the Division of Energetics, Mechanical Engineering, Mechanics, and Control Processes of RAS, and vice-president of the RAS Council for Research in the Area of Defense. For his active scientific and organizational activities, he was awarded the Order of the Red Banner of Labor in 1990, the Order forMerits Before the Fatherland of the 2nd degree in 1999, and the Order of Friendship in 2010. A N Lagarkov was born on August 8, 1939 in Moscow. On graduating in 1963 from the Faculty of Electronic Engineering of the Moscow Power Engineering Institute, he graduated from the postgraduate course of MPEI and defended his thesis for the degree of candidate of Physical andMathematical Sciences in 1967. That same year, he began working at the Theoretical Department (headed by the corresponding member of the USSR Academy of Sciences LM Biberman) of the Institute for High Temperatures of the USSR Academy of Sciences (IHTAS), where in 1977 he defended his doctoral thesis ``Some questions of the theory of transport phenomena.'' While working at IHTAS, A N Lagarkov performed a series of studies on radiation heating of bodies penetrating the dense atmospheric layers at a hypersonic speed. The results of these studies stimulated considerably the further development of the theory of energy transport by radiation in inhomogeneous plasma and hot gases. The methods of mathematical simulation elaborated by ANLagarkov turned out to be very effective in the study of properties of dense gases, liquids, melts, and dense plasma. A N Lagarkov became one of the founders of a new scientific disciplineÐ the molecular dynamics method. In the early 1980s, work was started under the guidance of A N Lagarkov on creating and investigating inhomogeneous composite materials and structures in which the interaction of an electromagnetic field with structure elements is of a nonpotential character. For carrying out research in this field, the Scientific Center for Applied Problems in Electromagnetics (SCAPE) was founded on the basis of IHTAS on the initiative of A N Lagarkov, who became its director. In 1999, he became director of ITAE RAS, the former SCAPE. Since 2017, ANLagarkov has been the research supervisor of ITAE RAS. During this time, fundamental studies were undertaken under A N Lagarkov's guidance, the results of which are widely acknowledged in the world scientific community. He and his colleagues were the first in the world to create a composite material containing no ferromagnetic inclusions and having negative values of magnetic permeability in the microwave range. Composites with negative values of dielectric permittivity in the microwave range were also created and investigated. The corresponding scientific publications were several years ahead of reports on analogous work done in Great Britain and the USA and underlay the development of metamaterials, interest in the study of which has been keen till the present day. Uspekhi Fizicheskikh Nauk 189 (10) 1129 ± 1130 (2019) DOI: https://doi.org/10.3367/UFNr.2019.08.038657 Translated by M V Tsaplina PERSONALIA PACS number: 01.60.+q

AbstractWe have experimentally studied the dynamics of impact-ionization switching in semiconductor structures without p – n junctions when subnanosecond high-voltage pulses are applied. Silicon n ^+– n – n ^+ type structures and volume ZnSe samples with planar ohmic contacts exhibit reversible avalanche switching to the conducting state within about 200 ps, which resembles the well-known phenomenon of delayed avalanche breakdown in reverse-biased p ^+– n – n ^+ diode structures. Experimental data are compared to the results of numerical simulations.

The transient process in an RC circuit with a reverse-biased 4H-SiC p+−i−n+ diode serving as a capacitor has been numerically simulated using the SILVACO TCAD software environment. The model experiment has shown that the charge time of an optimally designed 4H-SiC p+−i−n+ capacitor with dopant incomplete ionization is roughly an order of magnitude shorter than in the hypothetical case of complete ionization. The potential effect of the dopant ionization dynamics on the transient process has been found.

Влияние частичной ионизации легирующих примесей в 4H-SiC на емкость обратносмещенного p +-i-n + -диода

We have experimentally studied the dynamics of impact-ionization switching in semiconductor structures without p–n junctions when subnanosecond high-voltage pulses are applied. Silicon n+–n–n+ type structures and volume ZnSe samples with planar ohmic contacts exhibit reversible avalanche switching to the conducting state within about 200 ps, which resembles the well-known phenomenon of delayed avalanche breakdown in reverse-biased p+–n–n+ diode structures. Experimental data are compared to the results of numerical simulations.

The time characteristics of pulse generators based on sharp-recovery 4H : SiC drift diodes have been calculated. It has been found that the speed of n-base 4H-SiC diodes is superior to that of p-base diodes with the amplitude and initial pedestal in the output voltage (< 5% of the amplitude) versus the time curve being the same.

p + – n 0 – n + 4 H -SiC diodes with homogeneous avalanche breakdown at 1860 V are fabricated. The pulse current–voltage characteristics are measured in the avalanche-breakdown mode up to a current density of 4000 A/cm 2 . It is shown that the avalanche-breakdown voltage increases with increasing temperature. The following diode parameters are determined: the avalanche resistance (8.6 × 10 –2 Ω cm 2 ), the electron drift velocity in the n 0 base at electric fields higher than 10 6 V/cm (7.8 × 10 6 cm/s), and the relative temperature coefficient of the breakdown voltage (2.1 × 10 –4 K –1 ).

Исследование процесса выключения интегрального тиристора импульсом базового тока© И.В

The results of studying silicon semiconductor devices with nanosecond turning-on times, that is, fast-ionization dynistors (FIDs), are presented. The effect of an abrupt increase in the leakage current that flows through an FID upon blocking of the power voltage after the termination of a train of switched pulses is discovered and described. It is shown that under certain conditions this effect may result in the destruction of the FID. Methods for modifying FIDs are presented that allow stabilization of the leakage current.