Key Engineering Materials Vol. 1024

Abstract: This study presents a systematic investigation into the influence of gold nanoparticles on the performance of a self-powered metal-semiconductor-metal (MSM) 4H-SiC UV photodetector (SiC-UVPD), with a focus on the nonsymmetric contact phenomenon arising from differences in the contact areas of the gold electrode pair under 254 nm UV light exposure. The self-powered SiC-UVPD device exhibited a very good sensitivity of 9.34 x 10⁴, great responsivity of 0.30 A/W, and excellent detectivity of 7.0 x 10¹¹ cm. Hz^1/2.W^-1 under 254 nm UV light without any external power. In fact, the specific detectivity of the self-powered SiC-UVPD improved by 70 % following the application of Au nanoparticles. Self-powered photodetectors are desirable devices for green energy applications due to their unique advantages such as smaller footprints and wireless operation.

Abstract: Low gain avalanche detectors (LGADs) offer high temporal resolution for high energy particle detection, which is critical for next generation experiments in hadron colliders. While silicon LGADs (Si-LGADs) have rapidly matured in the last decade, research into silicon carbide (SiC) LGADs has only recently begun. By accounting for fundamental differences in material properties and fabrication processes, we present a prototype device design and process flow for 4H-SiC LGADs with etch-based isolation. Critical steps of the process flow and their results are discussed, including plasma etching, passivation, and the formation of low resistivity contacts. Electrical characterization (I-V, C-V) shows sufficient depletion of the device structure to demonstrate low-gain charge carrier multiplication.

Abstract: Silicon Carbide (SiC) is renowned for its exceptional thermal stability, making it a crucial material for high-temperature power devices in extreme environments. While optically detected magnetic resonance (ODMR) in SiC has been widely studied for magnetometry, it requires complex setups involving optical and microwave sources. Similarly, electrically detected magnetic resonance (EDMR) in SiC, which relies on an electrical readout of spin resonance, has also been explored for magnetometry. However, both techniques require microwave excitation, which limits their scalability. In contrast, SiC’s spin-dependent recombination (SDR) currents enable a purely electrical approach to magnetometry through the near-zero field magnetoresistance (NZFMR) effect, where the device resistance changes in response to small magnetic fields. Despite its potential, NZFMR remains underexplored for high-temperature applications. In this work, we demonstrate the use of NZFMR in SiC diodes for high-temperature relative magnetometry and achieve sensitive detection of weak magnetic fields at temperatures up to 500°C. Our technology provides a simple and cost-effective alternative to other magnetometry architectures, eliminating the need for a microwave source or complex setup. The NZFMR signal is modulated by an external magnetic field, which alters the singlet-triplet pair ratio controlled by hyperfine interactions between nuclear and electron/hole spins, as well as dipole-dipole/exchange interactions between electron and hole spins, providing a novel mechanism for relative magnetometry sensing at elevated temperatures. A critical advantage of our approach is the sensor head's low power consumption, which is less than 0.5 W at 500°C for magnetic fields below 5 Gauss. This approach provides a sensitive, reliable, and scalable solution with promising applications in space exploration, automotive systems, and industrial sectors, where high performance in extreme conditions is essential.

Abstract: The next space missions require power levels that current space qualified semiconductor technology cannot provide. The silicon carbide devices are considered to overcome these challenges, and provide the required technical performance. European space industry is asked in individual meetings about their specific needs and requirements, this information is gathered, classified and presented to the silicon carbide manufacturers. This work is the connection between the two industries to better understand the requirements and applications, and build a new business case for the SiC devices in space applications.

Abstract: This work proposes SiC half-bridge modules to improve the high-power motor drive systems in space. The high current capability of the modules allows to reduce the number of required components, reducing the required PCB area. Using analytical loss calculation models the losses and the efficiency of the Si and SiC configurations is calculated, obtaining better results with the SiC due to the lower conduction losses, even if the voltage rating of the devices is severely derated to avoid single event burnouts in the space application.

Abstract: High power and high voltage distributions will be required in space, but the necessary latching current limiters to manage the loads are not feasible with current Si P-MOSFET technology in the required power and voltage range. The generated losses and the number of parallel components make the system performance unacceptable. SiC N-MOSFETs are proposed as an alternative, due to their superior current ratings, reduced conduction resistance and increased thermal limits. Using these characteristics, two preliminary designs are proposed with SiC N-MOSFETs, one to optimize the power losses in the nominal operation and the other to reduce the required number of parallel devices and increase the allowable time under fault of the system. Both configurations overcome the challenges brought by the high power and high voltage distributions in space, reducing the losses and the complexity of the system while increasing the time under fault. This work shows how SiC technology can enable high power and high voltage distribution in space, while highlighting the importance of high power packages and thermal characteristics in certain applications.