PNNL

Abstract

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 like 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 emission (FP), and Fowler-Nordheim tunneling (FN) 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 irradiation. The reverse bias characteristics of N-polar diodes are less affected after fast neutron irradiation compared to Ga-polar diodes, while in the forward bias region, the electrical behavior after fast and thermal neutron irradiation is similar in Ga-polar and N-polar diodes. The results indicate that the role of orientation should be considered in design of GaN-based radiation-tolerant electronics.