The effects of high-energy uranium ion irradiation on Au/n-GaN Schottky diodes

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2014-11, Vol.339, p.20-25
• Main Authors: Gou, J., Zhang, C.H., Zhang, L.Q., Song, Y., Wang, L.X., Li, J.J., Meng, Y.C., Li, H.X., Yang, Y.T., Lu, Z.W.
• Format: Article
• Language: English
• Subjects: Au/GaN Schottky contact; C–V; Interface state; I–V; Swift heavy ions
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2014.08.014

The I–V and C–V characteristics of Au/n-GaN Schottky diodes irradiated with 290-MeV 238U32+ ions are presented. The U ions can penetrate the n-type GaN epi-layer with a thickness about 3μm grown on the c-plane of a sapphire substrate using the MOCVD technique, leaving a purely electronic energy deposition. The Au/n-GaN Schottky diodes were irradiated to successively increasing fluences from 1×109 to 5×1011ionscm−2. The measured I–V curves show that the height of the Schottky barrier decreases after irradiation and that the Schottky barrier almost disappears when the ion fluence reaches 5×1010ionscm−2. Meanwhile, the irradiation increases the series resistance. The C–V curves show that the capacitance drops sharply when the ion fluence reaches 5×1010ionscm−2. The dielectric constant also decreases following the irradiation. The changes of the electrical properties are ascribed to the neutralization of the donor-like surface state and the acceptor-like surface state due to the migration of Au atoms at the interface of Au/n-GaN under energetic U ions irradiations.