Activation of Mg impurities in epitaxial p-GaN with rapid thermal annealing assisted supercritical fluid treatment

The activation of an Mg acceptor in p-GaN with rapid thermal annealing (RTA) assisted low-temperature supercritical fluid (SCF) treatment (RTA-A-SCF) was investigated. After RTA-A-SCF treatment, the luminescence band of the N vacancy in the PL spectra was significantly suppressed. An evident decrease in H concentration is also observed in secondary ion mass spectrometer measurements, it indicates an obvious decrease of Mg–H complexes in the p-GaN. In addition, the ohmic contacts have been well improved and the hole concentration has increased by an order of magnitude. The activation mechanism of RTA-A-SCF treatment was further analyzed by X-ray photoelectron spectroscopy.