Structural and interfacial properties of high-k HfOxNy gate dielectric films

The thermal stability and interfacial characteristics for hafnium oxynitride (HfOxNy) gate dielectrics formed on Si (1 0 0) by plasma oxidation of sputtered HfN films have been investigated. X-ray diffraction results show that the crystallization temperature of nitrogen-incorporated HfO2 films increases compared to HfO2 films. Analyses by X-ray photoelectron spectroscopy confirm the nitrogen incorporation in the as-deposited sample and nitrogen substitution by oxygen in the annealed species. Results of FTIR characterization indicate that the growth of the interfacial SiO2 layer is suppressed in HfOxNy films compared to HfO2 films annealed in N2 ambient. The growth mechanism of the interfacial layer is discussed in detail.