Preliminary investigation of hafnium oxide deposited via atomic layer chemical vapor deposition (ALCVD)

We report the preliminary results of our investigation on the use of Hf(NO₃)₄ as a precursor for atomic layer chemical vapor deposition (ALCVD) of HfO₂. X-ray diffraction analysis indicated that films deposited directly on H-terminated silicon surfaces were smooth, uniform, and amorphous and that film morphology could be altered by a post deposition anneal. X-ray photoelectron spectroscopy (XPS) analysis indicated that films are oxygen rich and that residual NO₃ and NO₂ from the precursor could be eliminated by a post-deposition anneal. For a ~42Å HfO₂ film, a dielectric constant of k ~10 and a capacitive equivalent thickness of approximately 16Å were obtained. The lower than expected dielectric constant may be due in part to the presence of an interfacial silicate layer and to excess oxygen