Dynamics of modification of Ni-GaN Schottky barrier diodes irradiated at low temperature by 200 MeV Ag~(14+) ions

摘要

Ni/GaN Schottky barrier diodes were irradiated with 200 MeV Ag ions up to fluence of 1 × 10~(11) ions/cm~2 at the substrate temperature of 80 K. Post-irradiation current-voltage measurements showed that the ideality factor, n increased and the reverse leakage current, I_R decreased with increase in fluence. But Schottky barrier height, Φ_b increased only marginally with increase in ion fluence. In situ resistivity measurements showed orders of magnitude increase in resistivity of GaN epitaxial film with irradiation fluence. Cross-sectional transmission electron microscopy images revealed the presence of defect clusters in bulk GaN after irradiation.