Comparative Study of SiC Microstructure Neutron Detectors

In order to meet the demand for neutron detection in extreme environments with high temperature, high pressure, and strong radiation, different Schottky-type microstructure neutron detectors based on the wide bandgap semiconductor material 4H-SiC are designed in this work. Detectors D1 and D2 used nickel (Ni) and high melting point tungsten (W) as the front Schottky contact electrode metals, respectively, while detector D3 added a silicon dioxide (SiO2) interlayer at the W metal-semiconductor interface. Current-voltage measurements show that the detectors D1-D3 have typical Schottky rectification characteristics. The transient current pulse response of the detectors is affected by different applied bias voltages and incident particle energies. At room temperature, the detector D3 with SiO2 interlayer shows the highest neutron detection efficiency of 6.57%. It also demonstrates that the SiO2 interlayer can reduce the leakage current due to high surface states and surface damage generated during process fabrication. The neutron irradiation of the detectors at high temperature (150 degrees C) is also studied, and very small differences in the energy spectra of the detectors are observed compared to those in a room-temperature environment, demonstrating that the 4H-SiC-based Schottky-type microstructure neutron detectors have the capability of detecting neutrons at high temperatures as well.