Deep levels in GaN studied by deep level transient spectroscopy and Laplace transform deep-level spectroscopy

In this study we present the results of investigations on Schottky Au-GaN diodes by means of conventional DLTS and Laplace DLTS methods within the temperature range of 77–350 K. Si-doped GaN layers were grown by Molecular Beam Epitaxy technique (MBE) on sapphire substrates. DLTS signal spectra revealed the presence of four majority traps: two hightemperature and two low-temperature peaks. Using LDLTS method and Arrhenius plots the activation energy and capture cross sections were obtained. For two high-temperature majority traps they are equal to E1 = 0.65 eV, σ1 = 8.2 × 10−16cm2 and E2 = 0.58 eV, σ2 = 2.6 × 10−15 cm2 whereas for the two low-temperature majority traps E3 = 0.18 eV, σ3 = 9.72 × 10−18 cm2 and E4 = 0.13 eV, σ4 = 9.17 × 10−18 cm2. It was also found that the traps are related to point defects. Possible origin of the traps was discussed and the results were compared with the data found elsewhere [1–5].