scholarly journals Detector Response to D-D Neutrons and Stability Measurements with 4H Silicon Carbide Detectors

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 568 ◽  
Author(s):  
Matteo Hakeem Kushoro ◽  
Marica Rebai ◽  
Marco Tardocchi ◽  
Carmen Altana ◽  
Carlo Cazzaniga ◽  
...  

The use of wide-band-gap solid-state neutron detectors is expanding in environments where a compact size and high radiation hardness are needed, such as spallation neutron sources and next-generation fusion machines. Silicon carbide is a very promising material for use as a neutron detector in these fields because of its high resistance to radiation, fast response time, stability and good energy resolution. In this paper, measurements were performed with neutrons from the ISIS spallation source with two different silicon carbide detectors together with stability measurements performed in a laboratory under alpha-particle irradiation for one week. Some consideration to the impact of the casing of the detector on the detector’s counting rate is given. In addition, the detector response to Deuterium-Deuterium (D-D) fusion neutrons is described by comparing neutron measurements at the Frascati Neutron Generator with a GEANT4 simulation. The good stability measurements and the assessment of the detector response function indicate that such a detector can be used as both a neutron counter and spectrometer for 2–4 MeV neutrons. Furthermore, the absence of polarization effects during neutron and alpha irradiation makes silicon carbide an interesting alternative to diamond detectors for fast neutron detection.

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1143
Author(s):  
Maximilian W. Feil ◽  
Andreas Huerner ◽  
Katja Puschkarsky ◽  
Christian Schleich ◽  
Thomas Aichinger ◽  
...  

Silicon carbide is an emerging material in the field of wide band gap semiconductor devices. Due to its high critical breakdown field and high thermal conductance, silicon carbide MOSFET devices are predestined for high-power applications. The concentration of defects with short capture and emission time constants is higher than in silicon technologies by orders of magnitude which introduces threshold voltage dynamics in the volt regime even on very short time scales. Measurements are heavily affected by timing of readouts and the applied gate voltage before and during the measurement. As a consequence, device parameter determination is not as reproducible as in the case of silicon technologies. Consequent challenges for engineers and researchers to measure device parameters have to be evaluated. In this study, we show how the threshold voltage of planar and trench silicon carbide MOSFET devices of several manufacturers react on short gate pulses of different lengths and voltages and how they influence the outcome of application-relevant pulsed current-voltage characteristics. Measurements are performed via a feedback loop allowing in-situ tracking of the threshold voltage with a measurement delay time of only 1 μs. Device preconditioning, recently suggested to enable reproducible BTI measurements, is investigated in the context of device parameter determination by varying the voltage and the length of the preconditioning pulse.


Author(s):  
Marco Buzzo ◽  
Mauro Ciappa ◽  
Wolfgang Fichtner

Abstract Secondary electrons potential contrast (SEPC) by scanning electron microscopy has emerged as a powerful tool for two-dimensional quantitative dopant imaging. The main component of the SEPC signal arises from the difference in the built-in potential between differently doped regions; which is very high in wide-band-gap semiconductors and particularly intense in SiC. This paper, after discussing the physical principles leading to the dopant contrast and the proper experimental setup, investigates the impact of relevant factors such as experimental conditions, surface effects, and sample preparation on image quality. The quantitative capabilities of this technique are demonstrated by the analysis of different test structures and prototypes of power devices such as MOSFET and JFET. The application to completely process devices demonstrates that SEPC represents an unequalled characterization technique, which provides accurate imaging and dopant profiling capabilities for silicon carbide devices.


Micro ◽  
2022 ◽  
Vol 2 (1) ◽  
pp. 23-53
Author(s):  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Giuseppe Greco

Wide band gap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) are excellent materials for the next generation of high-power and high-frequency electronic devices. In fact, their wide band gap (>3 eV) and high critical electric field (>2 MV/cm) enable superior performances to be obtained with respect to the traditional silicon devices. Hence, today, a variety of diodes and transistors based on SiC and GaN are already available in the market. For the fabrication of these electronic devices, selective doping is required to create either n-type or p-type regions with different functionalities and at different doping levels (typically in the range 1016–1020 cm−3). In this context, due to the low diffusion coefficient of the typical dopant species in SiC, and to the relatively low decomposition temperature of GaN (about 900 °C), ion implantation is the only practical way to achieve selective doping in these materials. In this paper, the main issues related to ion implantation doping technology for SiC and GaN electronic devices are briefly reviewed. In particular, some specific literature case studies are illustrated to describe the impact of the ion implantation doping conditions (annealing temperature, electrical activation and doping profiles, surface morphology, creation of interface states, etc.) on the electrical parameters of power devices. Similarities and differences in the application of ion implantation doping technology in the two materials are highlighted in this paper.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3367 ◽  
Author(s):  
Karl Stein ◽  
Moe Tun ◽  
Keith Musser ◽  
Richard Rocheleau

Battery energy storage systems (BESSs) are being deployed on electrical grids in significant numbers to provide fast-response services. These systems are normally procured by the end user, such as a utility grid owner or independent power producer. This paper introduces a novel research project in which a research institution has purchased a 1 MW BESS and turned ownership over to a utility company under an agreement that allowed the institution to perform experimentation and data collection on the grid for a multi-year period. This arrangement, along with protocols governing experimentation, has created a unique research opportunity to actively and systematically test the impact of a BESS on a live island grid. The 2012 installation and commissioning of the BESS was facilitated by a partnership between the Hawaii Natural Energy Institute (HNEI) and the utility owner, the Hawaiian Electric and Light Company (HELCO). After the test period ended, HELCO continued to allow data collection (including health testing). In 2018, after 8500 equivalent cycles, the BESS continues to operate within specifications. HNEI continues to provide HELCO with expertise to aid with diagnostics as needed. Details about the BESS design, installation, experimental protocols, initial results, and lessons learned are presented in this paper.


2018 ◽  
Vol 924 ◽  
pp. 621-624 ◽  
Author(s):  
Rahul Radhakrishnan ◽  
Nathanael Cueva ◽  
Tony Witt ◽  
Richard L. Woodin

Silicon Carbide JBS diodes are capable, in forward bias, of carrying surge current of magnitude significantly higher than their rated current, for short periods. In this work, we examine the mechanisms of device failure due to excess surge current by analyzing variation of failure current with device current and voltage ratings, as well as duration of current surge. Physical failure analysis is carried out to correlate to electrical failure signature. We also quantify the impact, on surge current capability, of the resistance of the anode ohmic contact to the p-shielding region.


2018 ◽  
Vol 31 (24) ◽  
pp. 9903-9920 ◽  
Author(s):  
Elina Plesca ◽  
Stefan A. Buehler ◽  
Verena Grützun

Atmosphere-only CMIP5 idealized climate experiments with quadrupling of atmospheric CO2 are analyzed to understand the fast response of the tropical overturning circulation to this forcing and the main mechanism of this response. A new metric for the circulation, based on pressure velocity in the subsidence regions, is defined, taking advantage of the dynamical stability of these regions and their reduced sensitivity to the GCM’s cloud and precipitation parameterization schemes. This definition permits us to decompose the circulation change into a sum of relative changes in subsidence area, static stability, and heating rate. A comparative analysis of aqua- and Earth-like planet experiments reveals the effect of the land–sea contrast on the total change in circulation. On average, under the influence of CO2 increase without surface warming, the atmosphere radiatively cools less, and this drives the 3%–4% slowdown of the tropical circulation. Even in an Earth-like planet setup, the circulation weakening is dominated by the radiatively driven changes in the subsidence regions over the oceans. However, the land–sea differential heating contributes to the vertical pattern of the circulation weakening by driving the vertical expansion of the tropics. It is further found that the surface warming would, independently of the CO2 effect, lead to up to a 12% slowdown in circulation, dominated by the enhancement of the static stability in the upper troposphere. The two mechanisms identified above combine in the coupled experiment with abrupt quadrupling, causing a circulation slowdown (focused in the upper troposphere) of up to 18%. Here, the independent effect of CO2 has a considerable impact only at time scales less than one year, being overtaken quickly by the impact of surface warming.


2010 ◽  
Vol 645-648 ◽  
pp. 1101-1106 ◽  
Author(s):  
Jürgen Biela ◽  
Mario Schweizer ◽  
Stefan Waffler ◽  
Benjamin Wrzecionko ◽  
Johann Walter Kolar

Switching devices based on wide band gap materials as SiC oer a signicant perfor- mance improvement on the switch level compared to Si devices. A well known example are SiC diodes employed e.g. in PFC converters. In this paper, the impact on the system level perfor- mance, i.e. eciency/power density, of a PFC and of a DC-DC converter resulting with the new SiC devices is evaluated based on analytical optimisation procedures and prototype systems. There, normally-on JFETs by SiCED and normally-off JFETs by SemiSouth are considered.


2011 ◽  
Vol 679-680 ◽  
pp. 726-729 ◽  
Author(s):  
David T. Clark ◽  
Ewan P. Ramsay ◽  
A.E. Murphy ◽  
Dave A. Smith ◽  
Robin. F. Thompson ◽  
...  

The wide band-gap of Silicon Carbide (SiC) makes it a material suitable for high temperature integrated circuits [1], potentially operating up to and beyond 450°C. This paper describes the development of a 15V SiC CMOS technology developed to operate at high temperatures, n and p-channel transistor and preliminary circuit performance over temperature achieved in this technology.


Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 869 ◽  
Author(s):  
Ayesha Kosar Fahad ◽  
Cunjun Ruan ◽  
Kanglong Chen

Transmissive metasurface-based dual-wide-band dual circular polarized operation is needed to facilitate volume and size reduction along with polarization diversity for future THz wireless communication. In this paper, a novel dual-wide-band THz linear polarization to circular polarization (LP-to-CP) converter is proposed using transmissive metasurfaces. It converts incident X polarized waves into transmitted left-hand circular polarized (LHCP) and right-hand circular polarized (RHCP) waves at two frequency bands. The structure consists of bi-layered metasurfaces having an outer conductor square ring and three inner conductor squares diagonally intersecting each other. The proposed converter works equally well with incident Y polarizations. Operational bandwidths for the dual-band LP-to-CP are 1.16 THz to 1.634 THz (34% fractional bandwidth) and 3.935 THz to 5.29 THz (29% fractional bandwidth). The electromagnetic simulation was carried out in two industry-standard software packages, High Frequency Structure Simulator (HFSS) and Computer Simulation Technology (CST), using frequency and time domain solvers respectively. Close agreement between results depicts the validity and reliability of the proposed design. The idea is supported by equivalent circuits and physical mechanisms involved in the dual-wide-band dual polarization operation. The impact of different geometrical parameters of the unit cell on the performance of LP-to-CP operation is also investigated.


Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1421
Author(s):  
Zhijun Li ◽  
Zuoxing Wang ◽  
Trillion Zheng ◽  
Hong Li ◽  
Bo Huang ◽  
...  

Compared with conventional silicon (Si)-based Pulse Width Modulation (PWM) rectifiers, PWM rectifiers based on silicon carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) have significant technical advantages and broad application prospects in terms of efficiency and power density, inherited from the high-speed switching feature. However, high-speed switching also induces gate-source voltage interference, which impacts the overall character of the conversion system. This paper considered the impact of gate-source voltage interference on loss, revealing an efficiency optimization for all-SiC PWM rectifiers. Firstly, this paper theoretically investigated the mechanism of improving the conversion system efficiency by using the 4-pin Kelvin packaged SiC MOSFETs. Then, based on the industrial product case study, loss distribution, using different package styles, was quantitatively analyzed. Finally, experiment test results verified the efficiency improvement of the PWM rectifier with the 4-pin Kelvin package SiC MOSFETs.


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