Study of the activation process of Mg dopant in GaN:Mg layers

Abstract

GaN:Mg layers with different concentration of Mg dopant were grown by metalorganic vapour phase epitaxy. The incorporation of Mg was verified by secondary ion mass spectroscopy. In order to dissociate Mg-related complexes and thus electrically activate the acceptor dopant, the as-grown layers were annealed in pure N 2 at ~800 °C for 30 minutes. The influence of the post-growth annealing on the layer properties was studied by photoluminescence (PL) and impedance spectroscopy. Impedance spectroscopy measurement showed that the annealed samples reveal higher charge concentrations and lower sheet resistance. Moreover, the relaxation time of hole traps decreased in annealed samples by one order of magnitude compared to as-grown samples. The changes in the electrical properties have been correlated with the changes in the PL spectra.

Scalable Vertical GaN FETs (SV- GaN FETs) for Low Voltage Applications

“…In vertical GaN MOSFET technology, ptype GaN is usually doped by magnesium (Mg) and the percentage activation of this impurity rarely exceeds 1%. Moreover, the fabrication and performance of high voltage GaN MOSFET structures are dependent on p-GaN doping techniques [6,7]. To overcome such technical limitations, our innovative idea is to expand the PSJ concept to Scalable Vertical (SV) GaN FETs.…”