Proton irradiation damage in silicon carbide junction barrier Schottky diode

BackgroundSilicon carbide junction barrier Schottky (SiC JBS) diode is a kind of power device based on wide bandgap semiconductor. SiC JBS diode is expected to become an important part of electric propulsion systems in the radiation application field in the future space exploration due to its excellent high-voltage, high-frequency and high-power characteristics. However, there are a large number of protons in the typical orbit of spacecraft, which always threaten the stable operation of spacecraft, including its key components.PurposeThis study aims to explore the resist ability of SiC JBSs to the degradation of medium energy proton irradiation, and clarify the mechanism of radiation effect of SiC JBSs from medium energy proton.MethodsBased the proton equivalent displacement damage dose in low Earth orbit for ten years, the SiC JBSs were firstly irradiated using 10 MeV protons at fluences ranging from 3×109 cm-2 to 3×1010 cm-2 at room temperature and without bias voltage. And the macro electrical characteristics of the SiC JBSs both before and after irradiation, including the forward current-voltage (I-V), reverse I-V and capacitance-voltage (C-V) characteristics, were tested. Then the irradiation-induced defects characteristics were tested by deep level transient spectrum (DLTS). Further, the related degradation mechanism that was associated with this phenomenon was also investigated using based on the test data and mathematical calculation. Finally, irradiation experiments of accelerator protons were carried out for commercial SiC JBSs.ResultsThe results show that the forward electrical characteristic of the SiC JBSs is stable, and the leakage current decreases at low reverse safety voltage. But the rated breakdown voltage is seriously degraded with the increase of irradiation fluence. The main contribution to the change of SiC JBSs characteristics originates from the increase of interface charge, deep level defects and Schottky barrier height, and the decrease of carrier density and carrier diffusion length in the drift region.ConclusionsAnalysis of the radiation damage process and mechanism of SiC JBSs in this study provides a research basis for its evaluation and verification before applied to medium energy proton environment.