Analysis of deep level defects in GaN p-i-n diodes after beta particle irradiation

The effect of beta particle irradiation (electron energy 0.54 MeV) on the electrical characteristics of GaN p-i-n diodes is investigated by current-voltage (I-V), capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS) measurements. The experimental studies show that, for the as-grown samples, three electron traps are found with activation energies ranging from 0.06 to 0.81 eV and concentrations ranging from 1.2 × 10¹⁴ to 3.6 × 10¹⁵ cm⁻³, together with one hole trap with energy depth of 0.83 eV and concentration of 8 × 10¹⁴ cm⁻³. It has been found that the irradiation has no effect on these intrinsic defects. The irradiation affected only a shallow donor level close to Ec [0.06 eV-0.18 eV] on the p-side of the p-i-n junction.