N-Doped LaAlO₃/Si(100) Films with High-k, Low-Leakage Current and Good Thermal Stability

High quality amorphous N-doped LaAlO₃ (LaAlON) films have been deposited on Si (100) in nitrogen gas by laser molecular beam epitaxy. The chemical nature and physical distribution of N in LaAlON films has been performed by x-ray photoemission spectroscopy. Compared with LaAlO₃, a significant improvement in the interfacial quality and leakage current density was obtained by nitrogen additive. At gate voltage +1V, the leakage current density of the LaAlON film with an equivalent oxide thickness as thin as 2nm is obtained to be 2.9× 10^-6A/cm², which decreases almost two orders of magnitude from that of LaAlO₃ film with the same thickness. Moreover, high-resolution transmission electron microscope analysis show that the LaAlON sample is still amorphous with a very sharp interface between the LaAlON layer and the Si substrate after annealed at 900°C for 60s.