Activation characteristics of ion-implanted Si+ in AlGaN.

Multiple-energy Si+ implantation in the range 30–360 keV into Al0.13Ga0.87N for n-type doping was carried out at room temperature, followed by annealing at 1150–1375 °C for 5 min. Activation efficiencies close to 100% were obtained for ion doses of 1.0×1015 cm-2 after annealing at 1375 °C, with a resulting sheet resistance of 74 Ω/square. By sharp contrast, the activation efficiency at 1150 °C was only 4% for this dose, with a sheet resistance of 1.63×104 Ω/square. The activation efficiency was also a function of dose, with a maximum activation percentage of only 55% for lower doses of 1.0×1014 cm-2 annealed at 1375 °C. This is due to the comparatively larger effect of compensating acceptors at the lower dose and is also lower than the corresponding activation of Si in pure GaN under these conditions (78%). The measurement temperature dependence of sheet carrier density showed an activation energy of 23 meV, consistent with the ionization energy of Si in AlGaN. [ABSTRACT FROM AUTHOR]