Radiation tolerance comparison of silicon and 4H–SiC Schottky diodes

Abstract

In this paper, silicon and 4H-silicon carbide (4H–SiC) based Schottky barrier diodes (SBD) have been compared for their radiation hardness capabilities through technology computer aided design (TCAD) simulations, using the non-ionizing energy loss (NIEL) mechanism. Both the devices are modeled for radiation effects after choosing same design points through interplay of drift layer doping and thickness for a fair comparison. Device simulation results show the superior radiation tolerance of 4H–SiC SBDs when compared to silicon devices under proton irradiation. On-state simulations reveal that the performance of Si and 4H–SiC diodes begin to degrade at a 1 MeV proton fluence of ~5 × 1011 and ~7 × 1012 cm−2, respectively. The higher radiation tolerance of 4H–SiC SBDs is also observed in off-state simulations. It is found that the reverse breakdown voltage decreases in silicon, whereas it increases in 4H–SiC devices under the effect of irradiation, mainly due to doping compensation mechanism. These observations validate experimental results available in literature and provide a way forward to use TCAD simulations for studying radiation effects in other devices.