Current deep-level transient spectroscopy investigation of acceptor levels in Mg-doped GaN

Abstract

The current deep-level transient spectroscopy (I-DLTS) technique was used to investigate acceptor levels in Mg-doped GaN grown by metalorganic vapor phase epitaxy. For activation of the Mg dopants, rapid thermal annealing was performed with a SiO2 encapsulation layer at 850 °C in N2. I-DLTS measurements on the Schottky diode fabricated revealed a discrete deep level located ∼112 meV above the valence band, corresponding to the energy level measured by conventional thermal admittance spectroscopy. This energy level is also in good agreement with the frequency dependence of the capacitance in view of the characteristic frequency. Therefore, this energy level can most probably be attributed to the Mg acceptor state itself.