Heavy-Ion Microbeam Studies of Single-Event Leakage Current Mechanism in SiC VD-MOSFETs

Abstract

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.

Impact of Terrestrial Neutrons on the Reliability of SiC VD-MOSFET Technologies

“…However, SiC devices are known to be susceptible to Single Event Burnout (SEB), Single Event Gate Rupture (SEGR) and Single Event Leakage Current (SELC). SEB and SEGR are caused, among others, by high-energy neutrons [7][8][9][10][11][12][13][14][15], while SELC has been reported only with heavy-ions [16][17][18][19][20].…”

Influence of Radiation-Induced Displacement Defect in 1.2 kV SiC Metal-Oxide-Semiconductor Field-Effect Transistors

“…Accordingly, SiC MOSFETs have been used in various applications, including automotives, aerospace, electric vehicle charging infrastructure, power supply, and unmanned aerial vehicles. However, previous studies [6][7][8][9][10][11] have revealed problems due to radiation in SiC MOSFETs. Problems such as an increased leakage current due to heavy ions [6] or threshold voltage shift due to the total ionizing dose (TID) [7], as well as catastrophic damage such as single-event burnout (SEB) [8][9][10][11] have been observed.…”

“…However, previous studies [6][7][8][9][10][11] have revealed problems due to radiation in SiC MOSFETs. Problems such as an increased leakage current due to heavy ions [6] or threshold voltage shift due to the total ionizing dose (TID) [7], as well as catastrophic damage such as single-event burnout (SEB) [8][9][10][11] have been observed. Therefore, reliability in radiation environments is important for the stable operation of various applications.…”

“…Therefore, the displacement damage in an SiC crystal would be accumulated overtime in terrestrial applications such as electrical vehicles, industry motor drives, and solar inverters. Furthermore, in particle-enriched environments, SiC MOSFETs become even more vulnerable to radiation, leading to device degradation and system failure [6][7][8][9][10][11].…”

Proton Irradiation-Induced Reliability Degradation of SiC Power MOSFET

“…Regarding the overall reliability of SiC MOSFETs, the gate oxide degradation remains an issue [17], [18]. Even though the intrinsic reliability of the gate SiO 2 has improved over the years, the material defects as well as the radiation impact have a significant effect on the oxide reliability [4]- [9], [19], [20]. On top of that, it is known that gate reliability of SiC MOSFETs is degraded during switching operation due to the "reach-through phenomenon", where the high electric field caused by the applied drain bias, is relocated closer to the gate oxide layer [21].…”