Electrical properties of Al$_{x}$Ga$_{1-x}$N implanted with Si at low doses

The investigation of ion implanted Al$_{x}$Ga$_{1-x}$N is still an immature subject compared to the research that explores the properties of GaN. A systematic electrical activation study of Si implanted Al$_{x}$Ga$_{1-x}$N grown on sapphire substrates by molecular beam epitaxy has been made as a function of ion dose and anneal temperature. Silicon ions were implanted at 200 keV with does ranging from 1x10$^{13}$ to 1x10$^{14}$ cm$^{-2}$ at room temperature. The samples were proximity cap annealed from 1100 to 1350 $^{o}$C with a 500 {\AA} AlN cap in a nitrogen environment. Hall Effect measurements show that an electrical activation efficiency of almost 100{\%} can be obtained for the Al$_{0.2}$Ga$_{0.8}$N implanted with doses of 5x10$^{13}$ and 1x10$^{14}$ cm$^{-2}$ and annealed at 1350 and 1300 $^{o}$C, respectively, for 20 min. An electrical activation efficiency of 87{\%} was achieved for the Al$_{0.1}$Ga$_{0.9}$N implanted with a dose of 1x10$^{14}$ cm$^{-2}$ after annealing at 1250 $^{o}$C for 20 min. These samples also exhibited a large mobility of 89 cm$^{2}$/V\textbullet s.