This work presents a novel Si-on-SiC laterally-diffused (LD) MOSFET structure intended to provide high breakdown voltage of 600 V and be resistant for harsh-environment space applications. Single-event effects (SEE) and total ionizing dose (TID) are investigated for the first time in such device. Initially, the considered Si LDMOS structure on SiC suffers from single-event burnout (SEB) at a drain voltage > 175 V, i.e. much lower than the target. An optimized LDMOS structure with a heavily doped extended P+ buried region is proposed and shown to be SEB resistant at the target drain voltage of 600 V, even for a highly-energetic ion with a linear energy transfer (LET) of 90 MeV/mg/cm2. TID simulations indicate that the main concern is the charge build-up in the thick field oxide (FOX). FOX positive charge density beyond 1x1011 cm-2 causes the breakdown voltage to drop below 200 V. Different oxide types which feature low “net” positive charge build-up have to be considered to allow for higher TID hardness. The proposed Si/SiC structure with a p+ region was shown to be resistant to a combined SEE and TID (in case of limited positive charge build-up in FOX) as well as combined SEE and high-temperature (up to 573 K) environments. In comparison to the equivalent Silicon-on-Insulator (SOI) LDMOS, the Si/SiC LDMOS structure with p+ buried region features similar immunity to SEB but allows for higher TID hardness.
Ben Ali, K., Gammon, P. M., Chan, C. W., Li, F., Pathirana, V., Trajkovic, T., Gity, F., Flandre, D., & Kilchytska, V. (2017). Single Event Effects and Total Ionising Dose in 600V Si-on-SiC LDMOS Transistors for Rad-Hard Space Applications. Proceedings of the 2017 47th European Solid-State Device Research Conference (ESSDERC), p. 6. https://hdl.handle.net/2078.5/226840