Impact of low-temperature annealing on defect levels generated by Mg-ion-implanted GaN

The impact of low-temperature annealing on Mg-ion-implanted GaN with a low dosage (1.5 x 10(11) cm(-2)) has been investigated using MOS diodes. Low-temperature annealing was carried out for Mg-ion-implanted GaN in the temperature range from 400 degrees C to 700 degrees C before forming the insulator/semiconductor interface of the tested MOS diodes. Upon annealing, the hysteresis and the slope of the capacitance-voltage (C-V) curves, which were affected by deep levels in the GaN bulk, were changed with the annealing temperature. In particular, the shape of C-V curve was changed by annealing at a temperature as low as 500 degrees C. The C-V curves were found to be reproducible by a simulation in which the dominant deep levels were assumed to be located at 0.1 and 0.7 eV below the conduction band edge. Considering the low recovery temperature and low dosage, the possibility of the existence of simple defects after implantation is discussed. (C) 2019 The Japan Society of Applied Physics