Electrical properties of AlN thin films prepared by ion beam enhanced deposition

Aluminum nitride (AlN) thin films prepared by ion beam enhanced deposition (IBED) have desirable properties as the buried dielectric in silicon-on-insulator substrates. In this work, the electrical properties of IBED deposited AlN films were investigated. Our results show that the electrical properties of AlN films deteriorate with increasing Al evaporation rate. The film deposited at a deposition rate of 0.05 nm/s exhibits good insulating properties and its breakdown field is 2.1 MV/cm. After thermal treatment, the breakdown field exceeds 4 MV/cm and the leakage current is reduced about 60 times. Capacitance-Voltage (C-V) results corroborate that the AlN film possesses an extremely low density of trapped charges. However, the density of the interfacial states inside the bandgap is relatively high in the non-abrupt AlN/Si interface region but they can be partially reduced by high-temperature annealing.