N-type conduction of sputter-deposited polycrystalline Al0.78Sc0.22N films by Si ion implantation

Abstract N-type conduction of sputter-deposited polycrystalline Al 0.78 Sc 0.22 N films was verified by Si ion implantation followed by activation annealing. The activation of dopants was found above an annealing temperature of 800 °C. Under a dose of 2 × 10 15 cm −2 with an activation annealing at 900 °C, n-type conduction was obtained with Hall mobility and a carrier concentration of 8.6 cm 2 V −1 s −1 and 8.9 × 10 18 cm −3 , respectively. The surface of n-type Al 0.78 Sc 0.22 N films was sensitive to humidity, and two orders of magnitude increase in the sheet resistance were measured. The phenomena can be understood by the formation of depletion from the backside of the film, caused by the balance between the spontaneous polarization and the surface charges.