Characterization of HfOxNy gate dielectrics using a hafnium oxide as target

Abstract Hafnium oxynitride (HfO x N y ) gate dielectric has been deposited on Si (1 0 0) by means of radio frequency (rf) reactive sputtering using directly a HfO 2 target in N 2 /Ar ambient. The thermal stability and microstructural characteristics for the HfO x N y films have been investigated. XPS results confirmed that nitrogen was successfully incorporated into the HfO 2 films. XRD analyses showed that the HfO x N y films remain amorphous after 800 °C annealing in N 2 ambient. Meanwhile the HfO x N y films can also effectively suppress oxygen diffusion during high temperature annealing and prevent interface layer from forming between HfO x N y films and Si substrates. AFM measurements demonstrated that surface roughness of the HfO x N y films increase slightly as compared to those pure HfO 2 films after post deposition annealing. By virtue of building reasonable model structure, the optical properties of the HfO x N y films have been discussed in detail.