Study on Defect States in GaN Epilayer Induced by Irradiation of High-Energy Electrons

Abstract

The defect states of an electron-beam irradiated GaN epilayer were characterized by capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS) measurements. The electron irradiation was performed using 1 and 2 MeV energy beams with 1 x 10(15) and 1 x 10(16) cm(-2) doses, respectively. The depth penetrated in the GaN epilayer by I MeV electrons appeared to be about 450 to 600 nm from the C-V measurement. Five defect states with activation energies of 0.34, 0.49, and 0.65 eV including two broad signals were observed by DLTS measurements, and it was suggested that they might originate from crystal damage during high-energy electron irradiation.