Silicon Carbide Technology Research Articles

A Low-power, High-gain and Excellent Noise Figure GaN-on-SiC LNA Monolithic Microwave Integrated Circuit (MMIC) operating at Ka-band for 5G/6G Application

A 25-40 GHz monolithic low-noise amplifier (LNA) is designed and fabricated with the 100 nm gallium nitride on silicon carbide (GaN-on-SiC) technology. This four-stage-cascade monolithic LNA performs a low DC power consumption of 150 mW and noise figure of 1.6-2.2 dB. Moreover, the gain of 34-37 dB with the continuous wave of more than 2 W over 24 hours can be achieved covering the operating bandwidth. Hence, this state-of-art LNA possesses a great potential to be directly integrated with GaN power amplifiers and other microwave components to realize the high-integration, high-reliability, and high-power RF front-end.

Design, Fabrication, and Characterization of a 4H-SiC CMOS Readout Circuit for Monolithic Integration with SiC Sensors

This paper reports the design and fabrication of a 4H-SiC CMOS readout circuit enabling monolithic integration of silicon carbide (SiC) sensors and circuits. Compared to conventional Si electronics, 4H-SiC integrated circuits can sustain operation in harsh conditions such as higher temperatures and radiation levels. The proposed amplifier performance is well balanced through the temperature range of 25C to 400C. Compared to state-of-the-art, the proposed SiC readout circuit does not include any off-chip components. The amplifier is fully differential, and hence shows improved common-mode rejection and signal-to-noise ratio (SNR). It can be monolithically integrated with SiC sensors in a scalable SiC technology.

Life-cycle energy demand comparison of medium voltage Silicon IGBT and Silicon Carbide MOSFET power semiconductor modules in railway traction applications

Power semiconductors process roughly 70 % of global energy, with a higher percentage expected as worldwide transport electrification, renewables and wide-band-gap (WBG) semiconductors are implemented, significantly affecting global energy savings. This manuscript evaluates the cumulative energy demand (CED) encompassing the manufacture and use-phase in a railway traction application of silicon (Si) and silicon carbide (SiC) power semiconductor modules. Realistic manufacturing data from a power semiconductor fab has been considered for 3.3 kV/450 A state-of-the-art Si and SiC LinPak modules. SiC devices presented around 2.6 – 3.8× higher CED per area than Si devices in the manufacturing phase. However, due to the considerably smaller SiC chip area per ampere required, a 1.1 – 1.6× lower grey energy than Si technology is estimated. For the first time, such analysis is based on specialized power semiconductor fab data for both technologies and provides a baseline for the life cycle energy assessment of power electronics systems. Besides, the use-phase energy losses were evaluated for a realistic railway application, considering an operational lifetime of 30 years. The module manufacturing energy is negligible compared to the use-phase stage. Furthermore, the SiC technology presented an estimated energy-saving potential of 24 MWh/lifetime per module compared to the Si device.

State-of-the-Art 800 V Electric Drive Systems: Inverter–Machine Codesign for Energy Efficiency Optimization

This paper introduces a state-of-the-art inverter–machine codesign methodology for achieving an energy-efficient electric drive system. The methodology is applied in an optimal design case study with the context of the latest trend in the 800 V system. To reduce the voltage rating, a three-level active neutral point clamped topology is utilized in the inverter design, incorporating silicon carbide technology for high-speed operation. This combination allows for efficient power conversion with reduced losses. In the machine design, the increased number of poles that can be achieved in the design phase, along with the utilization of high-speed switching frequencies, enables the development of more efficient machines. Based on the design of the experiment method, by optimizing the parameters of both the inverter and machine simultaneously, using a cosimulation model, the 7.7% of total energy loss during drive cycle operation can be improved.

25–31 GHz GaN-Based LNA MMIC Employing Hybrid-Matching Topology for 5G Base Station Applications

This letter presents a gallium nitride (GaN) high electron mobility transistor (HEMT)-based three-stage low noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) that can apply to the fifth-generation (5G) new radio base station applications. The designed GaN-based LNA MMIC utilizes a hybrid-matching topology with double-shunt capacitors at input and output (I/O) matching networks to achieve broad return loss (RL) and bandwidth characteristics across 5G frequency range two bands. The design is fabricated in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.15~\mu \text{m}$ </tex-math></inline-formula> GaN on silicon carbide technology and attains small signal gains greater than 21 dB, noise figures of 2.4–2.9 dB, 1-dB compression points greater than 19.1 dBm, output third-order intercept points greater than 28.5 dBm, and I/O RLs greater than 10 dB at 25–31 GHz band. The implemented design consumes a power of approximately 300 mW.

Radioactive ion beam opportunities at the new FRAISE facility of INFN-LNS

At the Laboratori Nazionali del Sud of INFN (INFN-LNS) in Catania, the construction of the new Radioactive Ion Beams (RIBs) facility FRAISE (FRAgment In-flight SEparator) has reached its ending phase. The facility uses the in-flight technique based on a primary beam fragmentation impinging on light Be or C targets. FRAISE makes use of light and medium mass primary beams, having power up to ≈ 2–3 kW, leading to RIBs, whose intensities vary in the range of ≈ 103–107 pps, for nuclei far from and close to the stability valley, respectively. FRAISE aims at providing high-intensity and high-quality RIBs for nuclear physics experiments, also serving to interdisciplinary research areas, such as medical physics. Critical aspects for high-quality beams are the tuning and transport, representing time-consuming processes and requiring dedicated diagnostics and tagging devices measuring many features of RIBs. Some of these devices should be capable to operate in radioactively activated environments because of the expected 2 kW beam lost in the dipole after the production target. Due to its peculiar robustness to radioactive damage, Silicon Carbide (SiC) technology has been considered for the detection layer. In this view, an R&amp;amp;D campaign has been started aiming at developing the FRAISE facility, the new diagnostics system, and a new tagging device, the latter of which will be useful for the CHIMERA multidetector beamline. In this paper, we discuss the status and the perspectives of the facility with a focus on the RIBs opportunities.

Analysis of SiC and SiC-Cascode MOSFET in the design of power electronics converters for more electric aircrafts

&lt;span&gt;Wideband gap (WBG) semiconductors have developed rapidly in recent years, enabling greater efficiency and power density in the design of power electronics converters for several areas of application. In this sense, this work analyzes the efficiency and specificities of silicon carbide (SiC) technologies and their cascode topology (SiC-Cascode), operating at high switching frequencies. The analyzes are performed using a Boost converter designed for conversion systems in the more-electric aircraft (MEA) context, where the alternating current (AC) power systems can operate at fixed frequency (115V/400Hz), or at variable frequency (115V/360-800Hz), such as observe in Boeing 787, and the direct current (DC) power system can operate with a DC bus of 400 V and +/-270 V are normally used. To validate the project, computer simulations were performed and a 1.0kW prototype was built in the laboratory. The performance analyses demonstrates that 97.5% of efficiency is achieved at 500 kHz switching frequency.&lt;/span&gt;

Polygon-Retrofitted Integrated Modular Motor Drive for Switched Reluctance Machines

Thanks to the absence of rotor windings and permanent magnets, switched reluctance motors have a small weight construction. The integration of a modular power converter in a switched reluctance motor leads to a highly compact and fault-tolerant motor drive with small weight and high power density. In this article, a polygon-retrofitted integration topology is proposed for switched reluctance motors. Both the switched reluctance motor and the power converter are cooled with one shared cooling circuit. The power converter is designed and implemented using silicon carbide technology for its low losses and small thermal resistance. The proposed integration topology is extensively studied using multiphysics modeling and experimental measurements on a fully integrated rotating setup. A highly compact and power dense drive of 3.1 kW/L is obtained.

The role of power device technology in the electric vehicle powertrain

In the automotive industry, the design and implementation of power converters and especially inverters, are at a turning point. Silicon (Si) IGBTs are at present the most widely used power semiconductors in most commercial vehicles. However, this trend is beginning to change with the appearance of wide-bandgap (WBG) devices, particularly silicon carbide (SiC) and gallium nitride (GaN). It is therefore advisable to review their main features and advantages, to update the degree of their market penetration, and to identify the most commonly used alternatives in automotive inverters. In this paper, the aim is therefore to summarize the most relevant characteristics of power inverters, reviewing and providing a global overview of the most outstanding aspects (packages, semiconductor internal structure, stack-ups, thermal considerations, etc.) of Si, SiC, and GaN power semiconductor technologies, and the degree of their use in electric vehicle powertrains. In addition, the paper also points out the trends that semiconductor technology and next-generation inverters will be likely to follow, especially when future prospects point to the use of “800 V" battery systems and increased switching frequencies. The internal structure and the characteristics of the power modules are disaggregated, highlighting their thermal and electrical characteristics. In addition, aspects relating to reliability are considered, at both the discrete device and power module level, as well as more general issues that involve the entire propulsion system, such as common-mode voltage.

A 26–30 GHz GaN HEMT Low-Noise Amplifier Employing a Series Inductor-Based Stability Enhancement Technique

This article presents a 26–30 GHz gallium nitride (GaN) high electron mobility transistor (HEMT) low-noise amplifier (LNA) for fifth-generation base station applications. In the proposed design, a series inductor-based stability enhancement technique was utilized to improve the reverse isolation and stability performance of the amplifier and to mitigate the effect of the parasitic capacitance of the GaN HEMT device. To validate the concept of the design, a three-stage GaN HEMT LNA was designed and fabricated in a 0.15-um GaN on silicon carbide technology. The demonstrated design achieved a gain of 20.2 dB, a noise figure of 2.4–2.5 dB, an output 1-dB compression point of 17.2 dBm, and an output third-order intercept point of 32.2 dBm. The design also attained stability (μ criterion) up to 7.7 at the operating frequency. The implemented design consumed power of 320 mW with a nominal supply of 10 V.

An Overview about Si, Superjunction, SiC and GaN Power MOSFET Technologies in Power Electronics Applications

This work presents a comparative analysis among four power MOSFET technologies: conventional Silicon (Si), Superjunction (SJ), Silicon Carbide (SiC) and Gallium Nitride (GaN), indicating the voltage, current and frequency ranges of the best performance for each technology. For this, a database with 91 power MOSFETs from different manufacturers was built. MOSFET losses are related to individual characteristics of the technology: drain-source on-state resistance, input capacitance, Miller capacitance and internal gate resistance. The total losses are evaluated considering a drain-source voltage of 400 V, power levels from 1 kW to 16 kW (1 A–40 A) and frequencies from 1 kHz to 500 kHz. A methodology for selecting power MOSFETs in power electronics applications is also presented.

Portable Spectroscopy System for Environmental Monitoring: An SO2 Case Study

In this work, a compact, portable, extended operating life, maintenance-free and remotely operable apparatus for optical absorbance measurements in the ultraviolet region is proposed. The system is useful for concentration measurement of chemical species or biological agents that exhibit ultraviolet light absorption. An apparatus prototype was developed using a commercial LED as photons source at the desired wavelength and a photo-detector with low noise, high sensitivity and visible blindness, opportunely fabricated using Silicon Carbide technology. A suitable electronic for handling the very low-level current of the detector has been designed and built to be robust, portable, low-power, low-cost and with a WiFi user interface. The ultraviolet spectroscopy apparatus application to which this work is aimed, is the low-level concentration measurement of SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in volcanic environment, while it can be easily adapted to other molecules detection and higher concentration level. While in previous Authors’ work the system feasibility has been explored using laboratory instrumentation, in this work the focus is to design a system that can be used in real harsh volcanic environment, where system lightweight, endurance and chemical strength against aggressive compounds are paramount. Resolution of approximately 1 ppm, compactness, robustness and insensitivity to humidity and temperature variations are required for this kind of environment. The performed laboratory tests and calibration for SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> monitoring, are reported and discussed. The system shows good sensitivity as high as 8 pA/ppm, a resolution < 1 ppm for SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> detection and low cross-sensitivity to main components usually present in volcanic gases.

Auxiliary Power Supplies for High-Power Converter Submodules: State of the Art and Future Prospects

Recent developments in medium-voltage (MV) silicon and silicon carbide (SiC) power semiconductor devices are challenging state-of-the-art converter and auxiliary power supply (APS) designs. The APS is an important converter component, which energizes the gate-drive units and, therefore, has an influence on the overall reliability and efficiency of the converter system. There has, however, been comparably little research on how the APS of high-power converter submodules can be realized, in particular, for high-voltage applications. New, or improved, solutions may build on state-of-the-art topologies in the near future, but utilize MV SiC technology in the APS circuit itself to enable improved efficiency, reliability, simplicity, and compactness. Externally-fed APS concepts could provide several further advantages. Their various benefits on converter and system level may enable them to be a competitive solution for future APS concepts. Especially, light-based power supply systems are considered most useful since they offer extreme voltage isolation capability and immunity to electromagnetic interference. This article presents a review of the wide range of solutions for APSs, possible implementation options, and the most important design considerations. The different solutions are evaluated in a qualitative fashion, providing an overview of available APS concepts with regard to the requirements for high-power converter applications.

Silicon Carbide Photonics Bridging Quantum Technology

In the last two decades, bulk, homoepitaxial, and heteroepitaxial growth of silicon carbide (SiC) has witnessed many advances, giving rise to electronic devices widely used in high-power and high-frequency applications. Recent research has revealed that SiC also exhibits unique optical properties that can be utilized for novel photonic devices. SiC is a transparent material from the UV to the infrared, possess nonlinear optical properties from the visible to the mid-infrared and it is a meta-material in the mid-infrared range. SiC fluorescence due to color centers can be associated with single photon emitters and can be used as spin qubits for quantum computation and communication networks and quantum sensing. This unique combination of excellent electronic, photonic and spintronic properties has prompted research to develop novel devices and sensors in the quantum technology domain. In this perspective, we highlight progress, current trends and prospects of SiC science and technology underpinning the development of classical and quantum photonic devices. Specifically, we lay out the main steps recently undertaken to achieve high quality photonic components, and outline some of the current challenges SiC faces to establish its relevance as a viable photonic technology. We will also focus on its unique potential to bridge the gap between classical and quantum photonics, and to technologically advance quantum sensing applications. We will finally provide an outlook on possible alternative applications where photonics, electronics, and spintronics could merge.

Nanoscale limit of the thermal conductivity in crystalline silicon carbide membranes, nanowires, and phononic crystals

Silicon carbide (SiC) aims to be the number one material for power microelectronics due to its remarkable thermal properties. Recent progress in SiC technology finally enabled the fabrication of crystalline SiC nanostructures. Yet, the thermal properties of SiC at the nanoscale remain overlooked. Here, we systematically study heat conduction in SiC nanostructures, including nanomembranes, nanowires, and phononic crystals. Our measurements show that the thermal conductivity of nanostructures is several times lower than that in bulk and that the values scale proportionally to the narrowest dimension of the structures. In the smallest nanostructures, the thermal conductivity reached 10% of that in bulk. To better understand nanoscale thermal transport in SiC, we also probed phonon mean free path and coherent heat conduction in the nanostructures. Our theoretical model links the observed suppression of heat conduction with the surface phonon scattering, which limits the phonon mean free path and thus reduces the thermal conductivity. This work uncovers thermal characteristics of SiC nanostructures and explains their origin, thus enabling realistic thermal engineering in SiC microelectronics.

Conceptualization and Efficiency Review of Integrated Chargers Using Six-Phase Machines

Three integrated battery charger concepts based on six-phase electrical machines (EMs) are presented in this article. State-of-the-art topologies for galvanically isolated integrated chargers are reviewed as a basis for a novel integrated charger using the electrical drive (e-drive) as an isolated dc/dc converter, while the rotor is kept at standstill. Efficiency levels up to 88% and a cost breakdown are reported. Furthermore, the well-known reconfigurations of three-phase machines are reviewed and proposed as a basis for novel series-connected boost–buck converters, in which each stage is represented by one of the two three-phase machine windings and power electronic converters. The efficiency analysis of a 144-kW e-drive under this 6.6-kW dc biased battery charging condition is presented. The EM iron losses are calculated with finite-element method (FEM) using new Steinmetz parameters based on ring core measurements reflecting charging conditions. In addition, the dc and ac copper losses are analytically calculated. Moreover, inverter losses are analyzed based on their own switching loss measurements. The calculated efficiency of the integrated charger is compared with measurement results. The difference in efficiency between both remains within ±1% and efficiency levels up to 93% are reported. Finally, silicon carbide technology shows enhanced efficiencies.

Static DC Transformer Based on Negative Capacitance and High Voltage Engineering

Abstract: For DC voltage amplification, the operational amplifier is mostly used in the non-inverting configuration. In this case, the DC voltage amplification is done using a negative capacitance converter. Since the feedback capacitor acts as an open circuit for DC signal, it provides isolation between input and output. The amplified voltage level is limited by the breakdown voltage of the transistors used to build the op-amp and further the insulation breakdown limit of the Miller capacitor. By making use of new technologies such as silicon carbide technology, the breakdown voltage of transistors can be made higher even 1.2 KV and combined with high voltage engineering for capacitive insulation such as polymer capacitors, this can become a huge breakthrough in electric power engineering. Additionally, it can be used as a effective DC source for electric vehicles. The nominal voltage used in hybrid vehicles ranges from 100V to 200V.For electric-only vehicles, the required voltage is as high as 800V.The simulations are done using MIT Circuit sandbox, an open source circuit simulation tool. Keywords: DC amplifier, Op-amp, negative capacitance, silicon carbide and high voltage insulation.

Silicon Carbide Technology for Advanced Human Healthcare Applications.

Silicon carbide (SiC) is a highly robust semiconductor material that has the potential to revolutionize implantable medical devices for human healthcare, such as biosensors and neuro-implants, to enable advanced biomedical therapeutic applications for humans. SiC is both bio and hemocompatible, and is already commercially used for long-term human in vivo applications ranging from heart stent coatings and dental implants to short-term diagnostic applications involving neural implants and sensors. One challenge facing the medical community today is the lack of biocompatible materials which are inherently smart or, in other words, capable of electronic functionality. Such devices are currently implemented using silicon technology, which either has to be hermetically sealed so it does not directly interact with biological tissue or has a short lifetime due to instabilities in vivo. Long-term, permanently implanted devices such as glucose sensors, neural interfaces, smart bone and organ implants, etc., require a more robust material that does not degrade over time and is not recognized and rejected as a foreign object by the inflammatory response. SiC has displayed these exceptional material properties, which opens up a whole new host of applications and allows for the development of many advanced biomedical devices never before possible for long-term use in vivo. This paper is a review of the state-of-the art and discusses cutting-edge device applications where SiC medical devices are poised to translate to the commercial marketplace.

New FOM-Based Performance Evaluation of 600/650 V SiC and GaN Semiconductors for Next-Generation EV Drives

The drive inverter represents a central component of an electric vehicle (EV) drive train, being responsible for the DC/AC power conversion between the battery and the electrical machine. In this context, novel converter topologies adopting modern 600/650V wide bandgap (WBG) semiconductor devices will play a crucial role in improving the performance of next-generation drive inverters. In fact, WBG devices theoretically allow to achieve both higher inverter power density and higher conversion efficiency with respect to conventional silicon (Si) IGBT based solutions. Even though silicon carbide (SiC) devices are already well established in the automotive industry, high-voltage gallium nitride (GaN) devices are rapidly entering the market, promising higher theoretical performance but featuring a lower degree of maturity. As a consequence, it is currently not clear which semiconductor technology is most suited for future EV drive inverters. Therefore, this paper aims to address this gap providing a comparative performance evaluation of state-of-the-art SiC and GaN 600/650V active switches. In particular, a novel figure-of-merit (FOM) representing the minimum theoretical semiconductor losses under hard-switching operation is introduced. Remarkably, this FOM enables a fair and accurate performance comparison among semiconductor devices, allowing to clearly determine the best performing technology for a given set of application-specific conditions. The results of the comparative assessment show that currently available SiC and GaN active switch technologies can outperform each other depending on the semiconductor operating temperature and the converter switching frequency.

Medium Voltage Power Switch in Silicon Carbide—A Comparative Study

This paper discusses various solutions of energy conversion in medium voltage using power switches in Silicon Carbide (SiC) technology. In particular, a comparative study is focused on four different variants of an inverter phase leg operating at 1.5 kV DC, which has not been presented in the literature yet. The first one is based on a standard two-level half-bridge built from a 3.3 kV SiC MOSFET power module rated at 450 A. Then, the two-level solution with series-connected devices inside 1.2 kV/450 A power modules is taken into account. Finally, a flying-capacitor phase leg also based on the same 1.2 kV devices is investigated in two different modes: a standard three-level operation and quasi-two-level mode with a significantly reduced capacitor. The presented study is founded on in-depth experiments: all four phase legs were designed, built, and tested in the laboratory. All versions were connected in a half-bridge configuration with an inductive load. Tests were conducted under identical conditions to test the overall performance and switching behavior for various gate resistances. In addition, different aspects are analyzed and compared in this paper, including parasitics, cooling performance, gate drivers and layout considerations, providing selection guidelines for power switches with SiC power devices in medium voltage power electronics applications.