Electrical characterization of two deep electron traps introduced in epitaxially grown n-GaN during He-ion irradiation

Abstract

Epitaxial n-GaN was irradiated with 5.4-MeV He ions. Capacitance–voltage (C–V) measurements showed that 5.4-MeV He ions remove free carriers at a rate of 6200±300 cm−1 in the first micron below the surface. Deep level transient spectroscopy (DLTS) revealed that, in addition to the radiation-induced defects previously detected by DLTS at 0.18–0.20 eV below the conduction band, He-ion irradiation introduced two additional prominent defects, ER4 (EC-0.78 eV) and ER5 (EC-0.95 eV) at rates of 1510±300 and 3030±500 cm−1, respectively. Capture cross-section measurements revealed that electron capture kinetics of ER5 is similar to that of a line defect.