Heavy-ion microbeams are employed for probing the radiation-sensitive regions in commercial silicon carbide (SiC) vertical double-diffused power (VD)-MOSFETs with micrometer accuracy. By scanning the beam spot over the die, a spatial periodicity was observed in the leakage current degradation, reflecting the striped structure of the power MOSFET investigated. Two different mechanisms were observed for degradation. At low drain bias (gate and source grounded), only the gate-oxide (at the JFET or neck region) is contributing in the ion-induced leakage current. For exposures at drain–source bias voltages higher than a specific threshold, additional higher drain leakage current is observed in the p-n junction region. This provides useful insights into the understanding of basic phenomena of single-event effects in SiC power devices.

The High-Luminosity Large Hadron Collider (HL-LHC) is a novel machine configuration which will rely on a number of key innovative technologies to enhance the performance of the present LHC machine as of 2025. The upgrade will also involve increased radiation levels which need to be predicted by combining scaled measurements and calculations in order to define the qualification requirements for electronic systems. In this work we describe such levels first of all by introducing the monitoring and calculation approaches used for the present LHC machine, and secondly by applying scaling factors and dedicated simulations for the future HL-LHC accelerators. We present the levels according to the different areas relevant for the operation of electronics-based equipment, and discuss the associated Radiation Hardness Assurance implications.

High sensitivity of SiC power MOSFETs has been observed under heavy ion irradiation, leading to permanent increase of drain and gate leakage currents. Electrical post-irradiation analysis confirmed the degradation of the gate oxide and the blocking capability of the devices. At low drain bias, the leakage path forms between drain and gate, while at higher bias the heavy ion induced leakage path is mostly from drain to source. An electrical model is proposed to explain the current transport mechanism for heavy-ion degraded SiC power MOSFETs.

Accelerated terrestrial neutron irradiations were performed on different commercial SiC power MOSFETs with planar, trench, and double-trench architectures. The results were used to calculate the failure cross sections and the failure-in-time (FIT) rates at sea level. Enhanced gate and drain leakage were observed in some devices which did not exhibit a destructive failure during the exposure. In particular, a different mechanism was observed for planar and trench gate MOSFETs, the first showing a partial gate rupture with a leakage path mostly between the drain and the gate, similar to what was previously observed with heavy ions, while the second exhibiting a complete gate rupture. The observed failure mechanisms and the postirradiation gate stress (PIGS) tests are discussed for different technologies.

Total-Ionizing Dose (TID) and Displacement Damage (DD) are investigated in SiC power MOSFETs at ultra-high doses with 10-keV X-ray and 3-MeV protons. Significant parametric shifts in the electrical responses of the devices are observed depending on the bias condition and on the fabrication technology. Worst TID degradation is measured when positive gate-bias is applied during the irradiation, due to positive charge trapping in the gate oxide. Devices built in the latest generation SiC technology reveals a smaller subthreshold swing degradation, thanks to a better quality of the SiC/SiO ₂ interface. Devices exposed to 3-MeV protons exhibit a complex combination of TID and DD effects. The I-V and C-V measurements in SiC power MOSFETs identify two main degradation mechanisms: TID-induced charge trapping in the gate oxide and SiC/SiO ₂ interface, and DD-induced lattice damage in the SiC drift region, which degrades the series resistance of the devices.

Deep level transient spectroscopy (DLTS) and minority carrier transient spectroscopy (MCTS) are used to investigate electrically active defects in commercial SiC Schottky power diodes after heavy-ion microbeam irradiation at different voltages. The DLTS and MCTS spectra of pristine samples are analysed and compared to devices showing or not signatures of Single Event Leakage Current (SELC) degradation. An additional peak labelled ‘C’ with an activation energy of 0.17 eV below the conduction band edge is observed in the DLTS spectra of a sample degraded with SELC.