(Invited) Total Dose Effects and Single Event Upsets During Radiation Damage of GaN and SiC

Abstract

In critical defense applications and autonomous vehicles, there is an increasing transition from high-voltage Si power devices, which are limited in current ratings and power efficiency, to commercial wide bandgap (WBG) power devices. SiC and GaN power devices are now used in the automotive, wireless, and industrial power markets, but their adoption into space and avionic applications is hindered by their susceptibility to permanent degradation and catastrophic failure from heavy-ion exposure. Efforts to space qualify WBG power devices have revealed they are susceptible to damage from the high-energy, heavy-ion space radiation environment (galactic cosmic rays) that cannot be shielded. Higher voltage devices are more susceptible to these effects; as a result, to date, there are space-qualified GaN transistors now available, but limited to 300 V. Recent radiation testing of 600-V and higher GaN transistors has shown failure susceptibility at about 50% of the rated voltage, or less. Similarly, SiC power devices have undergone several generations of advances commercially, improving their overall reliability, but catastrophically fail at less than 50% of their rated voltage. SiC components have demonstrated susceptibility to radiation damage under heavy-ion single-event effects testing, reducing their utility in the space galactic cosmic ray (GCR) environment. In SiC-based Schottky diodes, catastrophic single-event burnout (SEB) and other single-event effects (SEE) have been observed at ~40% of the rated operating voltage, as well as an unacceptable degradation in leakage current at ~20% of the rated operating voltage. SEE caused by terrestrial cosmic radiation (neutrons) have also been identified by industry as a limiting factor for the use of SiC-based electronics in aircraft. Currently, small satellite applications require a Total Ionizing Dose (TID) resilience of 30 krad (Si) and Single Event Latch-up (SEL) hardened up to 80 MeV-cm2/mg linear energy transfer. Radiation hardening comes with a cost. As with Si power MOSFETs, electrical performance will suffer from hardening techniques. The two primary failure radiation damage concerns in current generations of electronics for space applications are (i) Single event upset, in which incident ionizing radiation results in the flipping of a bit from 0 to 1 or vice versa. While this may be a problem for data loss or operation, it does not lead to permanent damage of the device and (ii) Total dose failure, in which irradiation leads to the creation of a sufficient density of defects. These then lead to degradation of the electrical properties to the point of permanent failure. In this talk we will review radiation damage results for GaN and SiC and compare these to initial data for Ga2O3.Work performed as part of Interaction of Ionizing Radiation with Matter University Research Alliance (IIRM-URA ) , sponsored by the Department of the Defense, Defense Threat Reduction Agency under award HDTRA1-20-2-0002. The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred. *Current address: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706