Radiation effects in multilayer ohmic contacts Au-Ti-Al-Ti-n-GaN

Radiation effects in the Au-Ti-Al-Ti- n -GaN multilayer metallization subjected to irradiation with 60 Co γ-ray photons in the dose range 4 × 10 6 −2 × 10 7 Gy are considered, and the effect of radiation on the initial contact structures and the structures subjected to a rapid thermal annealing (RTA) at high-temperature in the nitrogen atmosphere is studied. Irradiation does not significantly affect the properties of structures that were not subjected to the heat treatment. An RTA at 700°C brings about a deterioration of the contact-layer morphology. The morphological and structural transformations in the contact metallization due to the RTA are enhanced by irradiation with γ-ray photons. The combined radiation-thermal treatment is conducive to the mass transfer between contacting layers. In addition, after γ-ray irradiation with the dose of 2 × 10 7 Gy, the oxygen-impurity atoms appear over the entire contact’s structure and are observed in a large amount in the near-contact GaN region.