Effect of Proton Radiation on Ultrawide Bandgap AlN Schottky Barrier Diodes

Lateral Pd/n-AlN Schottky barrier diodes (SBDs) were fabricated and subjected to 3-MeV proton irradiation at various fluences. Electrical and material characterization analysis was performed before and after each radiation fluence to quantify the change in device characteristics. It was found that the SBDs performed reliably up to a proton irradiation fluence of 5 × 10
¹³
cm
^-2
, with little or no change in the key device performance, such as current, turn-on voltage, ideality factor, breakdown voltage, and so on. The electrical characteristics of the SBDs were well-predicted using a standard thermionic emission theory. The performance of the SBDs shows a significant degradation after a high-fluence irritation of 5×10
¹⁵
cm
^-2
, where the current of the SBDs dropped two orders in magnitude. Material and surface characterizations, including atomic force microscopy and X-ray diffraction, indicated a consistent degradation in the AlN bulk crystal quality and a drastic increase in surface roughness. These results provide valuable information on the radiation properties of AlN electronics and can serve as important references for the future development of high-performance AlN devices for extreme environment applications.