Low-Temperature Annealing of Radiation-Induced Degradation in 4H-SiC Bipolar Junction Transistors

Radiation hardness is tested for 4H-SiC n-p-n bipolar junction transistors designed for 1200-V breakdown voltage by implanting MeV protons and carbon ions at different doses and energies. The current gain is found to be a very sensitive parameter, and a fluence as low as 1 × 10⁷ cm^-2 of 10 MeV ¹²C can be clearly detected in the forward-output characteristics, I_C(V_CE) . At this low dose, no influence of ion radiation is seen in the open-collector characteristics, I_B(V_EB), or the reverse bias leakage and breakdown properties. Moreover, by annealing the implanted devices at 420°C for 30 min, a complete recovery of the electrical characteristics is accomplished.