Acceptor doping of β-Ga₂O₃ by Mg and N ion implantations

Deep acceptor doping of β-Ga₂O₃ with Mg and N was demonstrated by implantation of the impurity ions into n-type bulk substrates. Systematic physical and electrical characterizations were performed to demonstrate recovery of the implantation-damaged crystals and electrical activation of the dopant atoms by thermal annealing at 1000–1200 °C in an N₂ atmosphere. N was found to exhibit much lower thermal diffusivity than Mg, thus enabling the use of higher annealing temperatures to maximize N activation efficiency without significantly altering the impurity profile. Consequently, an n-Ga₂O₃/Ga₂O₃:N/n-Ga₂O₃ structure was capable of sustaining a much larger voltage across its end terminals than its Mg-doped counterpart. The development of an ion implantation technology for acceptor doping of β-Ga₂O₃ creates unique opportunities for designing and engineering a variety of high-voltage β-Ga₂O₃ devices.