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

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 degreesC. 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.