Defects Induced by High-Temperature Neutron Irradiation in 250 µm-Thick 4H-SiC p-n Junction Detector

Area of Science:

• Materials Science
• Nuclear Engineering
• Semiconductor Physics

Background:

• Silicon carbide (SiC) detectors are crucial for harsh environment applications.
• Understanding radiation effects on SiC is vital for detector reliability.

Purpose of the Study:

• To investigate the electrical performance of 4H-SiC p-n junction detectors after high-temperature DT neutron irradiation.
• To analyze the impact of irradiation on current-voltage (I-V) and capacitance-voltage (C-V) characteristics.
• To characterize deep defect states and impurities using deep-level transient spectroscopy (DLTS).

Main Methods:

• Irradiation of 250 µm-thick 4H-SiC p-n junction detectors with DT neutrons (14.1 MeV) at 500 °C.
• Electrical characterization: I-V and C-V measurements.
• Deep-level transient spectroscopy (DLTS) from 85 K to 750 K.

Main Results:

• Unirradiated detectors showed ideal I-V characteristics with high electron mobility (µn) and built-in voltage (Vbi).
• High-temperature irradiation increased the ideality factor, decreased µn and Vbi, and significantly raised leakage current.
• Neutron irradiation reduced carrier concentrations in both p+-type and n-type SiC.
• DLTS revealed that irradiation influenced Z1/2 and EH6/7 trap behaviors.

Conclusions:

• High-temperature neutron irradiation degrades 4H-SiC detector performance by altering electrical properties and defect states.
• The study provides insights into the radiation hardness of SiC detectors under specific high-temperature conditions.
• Further research is needed to mitigate these radiation-induced effects.