https://iopscience.iop.org/article/10.1088/2515-7647/ab77a2/pdf

Silicon carbide color centers for quantum applications

Vertical gallium nitride (GaN) power devices are enabling next-generation power electronic devices and systems with higher energy efficiency, higher power density, faster switching, and smaller form factor. In Part I of this review, we have reviewed the basic design principles and physics of building blocks of vertical GaN power devices, i.e., Schottky barrier diodes and p-n diodes. Key topics such as materials engineering, device engineering, avalanche breakdown, and leakage mechanisms are discussed. In Part II of this review, several more advanced power rectifiers are discussed, including junction barrier Schottky (JBS) rectifiers, merged p-n/Schottky (MPS) rectifiers, and trench metal–insulator–semiconductor barrier Schottky (TMBS) rectifiers. Normally- OFF GaN power transistors have been realized in various advanced device structures, including current aperture vertical electron transistors (CAVETs), junction field-effect transistors (JFETs), metal–oxide–semiconductor field-effect transistors (MOSFETs), and fin field-effect transistors (FinFETs). A detailed analysis on their performance metrics is provided, with special emphasis on the impacts of key fabrication processes such as etching, ion implantation, and surface treatment. Lastly, exciting progress has been made on selective area doping and regrowth, a critical process for the fabrication of vertical GaN power devices. Various materials characterization techniques and surface treatments have proven to be beneficial in aiding this rapid development. This timely and comprehensive review summarizes the current progress, understanding, and challenges in vertical GaN power devices, which can serve as not only a gateway for those interested in the field but also a critical reference for researchers in the wide bandgap semiconductor and power electronics community.

Vertical GaN Power Devices: Device Principles and Fabrication Technologies—Part II

A review on high-frequency pulsed arc welding

Even though achieving carbon-free and reduced NOx emission transportation is a prevailing goal, the aviation industry is in its infancy to arrive at passenger class all-electric aircraft (AEA) properly operating over commercial missions. Challenges are mainly associated with components of the aircraft electric power system (EPS). Considering today’s technologies, power electronics components are not capable to sustain tens of megawatts of required power during the take-off and meet the aviation limits in terms of size, weight, and cost at the same time. State-of-the-art electrochemical energy units (EEU), including battery, fuel cell, and supercapacitor, cannot provide the 25-30 MW thrust power needed for the take-off, and electrical circuit breakers are not able to clear a fault in a large AEA propulsion system, and multi-megawatt electric drives/motors can barely be found being able to provide 2-3 MW thrust power so that they can be employed in a distributed propulsion architecture. Taking mentioned challenges into account, this article aims to tackle challenges associated with protection devices, EEUs, and electric machines in passenger class AEA, and present promising solutions using an envisioned MVDC ±5 kV EPS for an AEA, all-electric NASA N3-X aircraft. Based on findings and discussions made through the article, the authors conclude that although technology advancements are essential in all research areas, high voltage wide-bandgap electrical circuit breakers, Li-air and Li-S batteries with >1000 kW/kg specific power, and multi-megawatt superconducting electric machines will turn a commercialized passenger class AEA into reality within the next 20-30 years.

Components of Electrical Power Systems in More and All-Electric Aircraft: A Review

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.

https://ieeexplore.ieee.org/ielx7/6287639/6514899/09773161.pdf

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

Silicon (Si) power devices have dominated the world of Power Electronics in the last years, and they have proven to be efficient in a wide range of applications. But high power, high frequency and high temperature applications require more than Si can deliver. With the advance of technology, Silicon Carbide (SiC) and Gallium Nitride (GaN) power devices have evolved from immature prototypes in laboratories to a viable alternative to Si-based power devices in high-efficiency and high-power density applications. SiC and GaN devices have several compelling advantages: high-breakdown voltage, high-operating electric field, high-operating temperature, high-switching frequency and low losses. This paper provides a general review on the properties of these materials comparing some performance between Si and SiC devices for typical power electronics applications. Based on studied information, line of progress and the current state of developing, SiC seems to be the most viable substitute in high power and high temperature applications in the mid-term of Si, due to the fact that the GaN is still used in a reduced number of applications.

B. A. Luciano

Papers

SIC power devices in power electronics: An overview