Effects of fast and thermal neutron irradiation on Ga-polar and N-polar GaN diodes

Studies of the radiation tolerance and electrical behavior of gallium nitride (GaN) based devices are important for the next generation of high-power and high-voltage electronics that may be subjected to harsh environments such as nuclear reactor and fusion facilities, particle accelerators, and post-denotation environments. In this work, we study the behavior of Ga-polar and N-polar GaN Schottky diodes before and after exposure to fast and thermal + fast neutrons. Temperature-dependent current-voltage (I-V) and circular transmission line method (CTLM) measurements were used to study the electrical characteristics. A strong reduction in reverse leakage current and an increase in differential resistance in forward bias were observed after neutron irradiation. Thermionic emission (TE), Frenkel-Poole (FP) emission, and Fowler-Nordheim (FN) tunneling models were used to explain the forward and reverse I-V characteristics pre- and post-irradiation. The study confirms that Ga-polar and N-polar GaN Schottky diodes exhibit different electrical responses to fast and thermal neutron irradiations. The reverse bias characteristics of N-polar diodes are less affected after the fast neutron irradiation compared to Ga-polar diodes, while in the forward bias region, the electrical behavior after fast and thermal neutron irradiations is similar in Ga-polar and N-polar diodes. The results indicate that the role of orientation should be considered in the design of GaN-based radiation-tolerant electronics.

Automated summary

Studies on the radiation tolerance and electrical behavior of GaN-based devices are crucial for the development of next-generation high-power and high-voltage electronics that are likely to be exposed to severe environments. This research investigates the electrical characteristics of Ga-polar and N-polar GaN Schottky diodes before and after neutron irradiation. The results indicate that the reverse leakage current decreases significantly and the differential resistance increases in the forward bias after neutron irradiation. The study also reveals that the electrical responses of Ga-polar and N-polar diodes to fast and thermal neutron irradiations differ.