Combinatorial CVD of ZrO2 or HfO2 compositional spreads with SiO2 for high κ dielectrics

Abstract

A modified low-pressure chemical vapor deposition reactor was used to create compositional spreads of MO₂/SiO₂ films (M = Hf or Zr) on a single Si(100) wafer. Tri(tert-butoxy)silanol and anhydrous metal nitrates of hafnium and zirconium were used to grow films at temperatures as low as 130 °C. The films were characterized by ellipsometry and Rutherford backscattering spectrometry. The compositional spreads of 5–54% of Hf in the HfO₂/SiO₂ system and 5–62% of Zr in the ZrO₂/SiO₂ system are proposed to result from chemistry occurring between the two precursors. A survey of possible reactions involved in the deposition is included. The dielectric constant ranged from approximately 4 in the silica-rich locations to 17 in the ZrO₂-rich and HfO₂-rich locations.