Study on electrical properties of HfTiON and HfTiO gate dielectric Ge MOS capacitors with wet-NO surface pretreatment

Reactive co-sputtering is employed to prepare HfTiO/GeO_xN_y and HfTiON/GeO_xN_y stack gate dielectrics by using wet NO or N₂O surface pretreatment. The experimental results show that the wet NO pretreatment can lead to excellent interface properties, gate leakage properties and device reliability, especially for HfTiON/GeO_xN_y stack gate dielectrics. The involved mechanisms lie in N-barrier role and suitable N incorporation in GeO_xN_y interlayer, effectively preventing further increase of GeO_xN_y interlayer and the growth of unstable GeO_x during subsequent processing.