This paper presents a secondary ion mass spectrometry (SIMS) method for the analysis of semiconductor opening switch (SOS) diodes, which are crucial in nanosecond pulsed power systems. The study addresses the gap in experimental measurements of doping concentration in SOS diodes, as the current literature contains mainly theoretical doping profiles. The development of a reliable method for measuring doping concentration is expected to advance SOS technology, given the limited number of manufacturers. The SIMS technique is used to determine the depth distribution and concentration of dopants. The method is adapted to study boron, aluminum, and phosphorus in silicon, with emphasis on detection over several hundred micrometers to clarify the doping profile of SOS diodes. The experimental procedure includes (i) preparation of the SOS diode sample by cutting, polishing, and gold plating; (ii) performing dynamic SIMS analysis using specific conditions for boron/aluminum (O2+/M+) and phosphorus (Cs+/M−) detection; and (iii) using a line scan mode to measure element intensities across the sample, with quantification based on reference samples. The developed SIMS conditions enabled the measurement of the depth distribution of the dopants over a range of 1150 μm with a 2 μm step and providing sufficient lateral resolution. The quantified profiles of boron, aluminum, and phosphorus in the SOS diode are presented. The experimental impurity profiles were in partial agreement with the theoretical doping profiles. This method provides access to the analysis of semiconductor devices with thick structures, which are commonly used in power electronics and solid-state pulsed power.

Non-thermal plasma (NTP) technology offers an innovative solution for converting $\text{CO}_{2}$ into value-added products. Among the various possible reactions, dry reforming of methane (DRM) is particularly attractive as it enables the simultaneous conversion of two greenhouse gases into syngas, a key precursor for synthetic fuel production. Among the existing reactor configurations (dielectric barrier discharges, microwave plasmas, and gliding arcs), nanosecond repetitive pulsed discharges (NRP) have emerged as a promising solution. In this context, a prototype semiconductor opening switch (SOS) generator based on transient-voltage-suppression (TVS) diodes is under development. It provides parameters suitable for NTP-based $\text{CO}_{2}$ conversion: a voltage amplitude up to 15 kV, pulse durations of approximately 10 ns, pulse energy in the tens of mJ, and a pulse repetition frequency (PRF) exceeding 1 kHz in continuous mode and 10 kHz in burst mode. Current work focuses on the comparison of 3 pumping circuits.

Directed energy applications demand high-voltage pulses with GW peak power and subnanosecond rise times, along with high pulse repetition frequency (PRF) and extended operational lifetimes. Semiconductor Opening Switch (SOS) diodes offer a promising solution, providing kA switching currents, MV withstand voltage, and nanosecond switching capabilities at kHz PRFs. This work focuses on an SOS generator based on modern components with output parameters representative of directed energy applications: 300 kV voltage, 3 kA current, 10-20 ns rise time, and PRF up to 300 Hz. A preliminary circuit design of an all-solid-state nanosecond pulse generator is presented. Furthermore, numerical simulations of the SOS diode are carried out using Synopsys TCAD in order to optimize the doping profile for subsequent fabrication by epitaxy.

A system based on inductive energy storage and Semiconductor Opening Switch (SOS) diodes offers a promising solution for the development of nanosecond pulse generators. The SOS effect occurs when a silicon p + -p-n-n + structure, containing residua] electron-hole plasma after forward pumping, undergoes a current density of more than 1 kA/cm 2 within the reverse pumping. In this study, the numerical simulations of SOS diodes are conducted to gain insights into the dynamics of the SOS effect using Synopsys TCAD. Initially, the accuracy of the model is validated by comparing static voltage breakdown simulations with experimental results. Subsequently, a mixed-mode device with a circuit simulator is utilized to simulate the SOS effect and the processes occurring during the current cut-off stage. This research contributes to advancing the field of pulse power technology by providing valuable insights into the operation of SOS diodes using commercially available software.

This article investigates the impact-ionization switching mechanism in parallel-connected high-voltage thyristors, aiming to bridge the gap between experimental observations and numerical simulations. A novel experimental setup is designed to study four parallel thyristors triggered in impact-ionization wave mode, marking the first instance of such an arrangement. In addition to the experiment, a numerical simulation is used to assess the impact-ionization switching of high-voltage thyristors in parallel connection. The numerical simulation adopts a quasi-3-D model of the thyristor structure derived from a 2-D model, considering cylindrical symmetry. Three distinct scenarios are explored in the simulation: 1) static voltage breakdown; 2) suppression of unwanted ${d}V/{d}t$ triggering; and 3) delayed impact-ionization breakdown. The article presents a detailed comparison and discussion of the experimental and numerical simulation results related to impact-ionization switching.

This article investigates the use of off-the-shelf (OTS) diodes as opening switches in a 500-kV nanosecond pulsed power generator. A 40-J test bench based on a saturable pulse transformer and a primary thyratron switch is designed to evaluate the performance of the OTS diodes in comparison with standard semiconductor opening switch (SOS) diodes A distinguishing feature of the proposed circuit is the adjustability of the output pulse energy, which is achieved using flat hysteresis loop magnetic cores and variable reset magnetic field. The study confirms the operation of OTS diodes as an opening switch, although highlighting differences in the reverse current conduction that affect the generated voltage pulse characteristics. Based on the successful operation of the OTS diodes, a 500-kV pulsed power generator using an OTS Solid-State Opening Switch (GO-SSOS) is developed. The GO-SSOS provides output voltages of 100–500 kV across resistive loads from 50 $\Omega$ to 1 k $\Omega$ , with a pulse width of about 100 ns and a rise time of less than 40 ns. The generator achieves a peak power of 335 MW and demonstrates an overall energy efficiency in the range of 30%–70% depending on the load. Operation at a pulse repetition rate of 60 Hz is presented, showing a good reproducibility of the pulses with an amplitude and duration deviation of about 2% and 10%, respectively. No degradation of the OTS diodes has been observed after the tests (more than 1000 pulses). As an example of the possible applications of the GO-SSOS, corona discharge in the air is performed, also proving the stability of all the systems under conditions of strong electromagnetic interference.

This article demonstrates the impact-ionization switching of standard thyristors in a series-parallel configuration. The series-parallel triggering of thyristors holds a substantial promise for enhancing both voltage blocking and current capacity of the switch simultaneously. Nevertheless, the key obstacle in this context revolves around acquiring a suitable trigger generator, primarily because this trigger necessitates a combination of high dV/dt and low post-triggering energy to be applied to the thyristor assembly. Thus, a novel trigger circuit is developed to test a setup with two parallel branches, each having two series-connected thyristors (with a wafer diameter of empty set24 mm and a rated blocking voltage of 1.8 kV). These thyristors were tested in the impact-ionization switching mode using a single Marx generator. We conducted experiments in a current flow phase, where energy switching occurred by connecting an RLC discharge circuit. These experiments revealed that the thyristors transitioned from a blocking to a conducting state around similar to 400 ps, enabling the switching of a current pulse with an amplitude of similar to 17.5 kA and a d I/ dt of similar to 8.5 kA/mu s (limited by the circuit). Notably, the current imbalance between the thyristor parallel branches remained under 2%. To the best of our knowledge, this is the first reported instance of successfully triggering high-voltage thyristors connected in series-parallel in the impact-ionization wave mode.

Thyristors triggered in the impact-ionization wave mode is a promising switching method in pulsed power technology. This triggering approach enhances the current capability of standard thyristors, allowing switching a current pulse with an amplitude of 200 kA and a current rise time rate-of-change (dI/dt) of 58 kA/ $\mu \text{s}$ . Thyristor wafer area can be considered as one of the factors that are limiting the peak current amplitude and dI/dt. Switching thyristors in parallel is a possible solution to overcome these limitations. However, no evidence was found in the literature for successful parallel switching of standard thyristors in the impact-ionization wave mode. In this research, the possibility of parallel switching of two standard thyristors rated for 2.2 kV with a wafer diameter of 32 mm was investigated. A Marx generator equipped with a peaking module was used to charge the thyristor equivalent capacitance (1 nF) up to double its static breakdown voltage with a voltage rise time rate-of-change (dV/dt) of more than 1 kV/ns, as required for impact-ionization triggering. The diagnostic system includes two wideband voltage probes (VPs) with a subnanosecond time response, which allows simultaneous measurement of a voltage drop across each thyristor connected in parallel. Two stages of thyristor operation were investigated: 1) a triggering stage, without energy switching, when a dc bias voltage is applied; and 2) a current flow stage, with energy switching, when an $RLC$ discharge circuit is connected. In these experiments, thyristors change from blocking to conducting state within 400 ps, switching a current pulse with an amplitude of 11 kA and a dI/dt of 6 kA/ $\mu \text{s}$ (circuit limits). The current imbalance between the thyristors was less than 10%. To the best of the authors’ knowledge, it is the first time reported that high-voltage thyristors connected in parallel have been successfully triggered in the impact-ionization wave mode.

Semiconductor opening switch (SOS) diodes are capable to switch currents with a density of more than 1 kA/cm 2 and withstand nanosecond pulses with an amplitude of up to 1 MV. SOS diodes, however, require a specific pumping circuit that must simultaneously provide forward and reverse pumping currents with a time of $\sim $ 500 and $\sim $ 100 ns, respectively. Such a pumping circuit with energies $>$ 1 J typically requires a gas-discharge switch or a low-efficient solid-state solution. This study proposes a novel approach to pumping SOS diodes based on a spiral generator (SG) (also known as a vector inversion generator). Due to its wave characteristics, the SG produces a bipolar current discharge that meets the time duration and current amplitude required to pump an SOS diode. Moreover, the initial pulse from the spiral typically has a relatively low current amplitude compared to the opposite polarity secondary pulse, so the SOS diode can operate at very high efficiencies. This idea has been tested using an all-solid-state SG coupled with large-area SOS diodes (1 cm 2). With this combination, a voltage pulse of 62 kV having a rise time of only 11 ns was obtained on an open circuit load (3 pF, 1 $\text{M}\Omega $ ). The experiments were highly repeatable, with no damage to the components despite multiple tests. There is significant scope to further improve the results, with simple alterations to the SG.