Articles you may be interested inStudies of the interfacial structure of La Al O 3 thin films on silicon by x-ray reflectivity and angle-resolved x-ray photoelectron spectroscopy

In this letter, we report on the low temperature (∼350°C) growth of Hf–Al–O dielectric films with improved thermal stability and electrical characteristics for gate dielectric applications. A higher capacitance and improved interfacial properties were observed in the films deposited with NH3 ambient followed by ultraviolet radiation assisted oxidation annealing. The films containing 10.6at.% Al were found to remain amorphous after a 900°C furnace anneal for 1min in flowing nitrogen. The flat-band voltage was stabilized by nitrogen incorporation with negligible shift. An equivalent oxide thickness of 19Å and a dielectric constant of 20.4 were obtained in the best samples processed in NH3 and ultraviolet radiation ambient.

A low temperature method (∼400°C) for nitrogen incorporation in hafnia based dielectrics has been developed for future gate dielectric applications. Hf metal films were deposited on Si substrates in ammonia ambient and were subsequently oxidized under ultraviolet illumination. Using this method, an interfacial layer comprising Hf–Si–O–N bonding was formed at the hafnia-Si interface, which led to a substantial enhancement in the overall dielectric properties of the film. An equivalent oxide thickness of 11.5Å and leakage current densities lower than 10−4A∕cm2 at a gate bias of −1V were achieved by this approach.

No abstract

No abstract