Jean-Sébastien M. Lehn, S. Javed, D. M. Hoffman
May 1, 2006
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Journal
Chemical Vapor Deposition
Abstract
Alternatives to tetrakis(dialkylamido)zirconium and hafnium for use as precursors to zirconium and hafnium oxide films are examined. Tetrakis(trimethylhydrazido)zirconium and hafnium, Zr(NMeNMe 2 ) 4 and Hf(NMeNMe 2 ) 4 , and Hf[ t BUNCH 2 CH 2 N- t Bu] 2 are used with oxygen as precursors to zirconium and hafnium oxide films in a low-pressure CVD process at substrate temperatures <400 °C. The as-deposited films are amorphous, featureless, and transparent on glass. X-ray photoelectron spectroscopy (XPS) data shows that the films deposited using the hydrazido complexes and oxygen as precursors are carbon- and nitrogen-free, while the films obtained from Hf[ t BUNCH 2 CH 2 N- t Bu] 2 and oxygen have a composition HfO 1.6 C 0.06 N 0.2 . A thin (<1500 A) zirconium oxide film remains amorphous after annealing for 2 h at 950°C. The X-ray crystal structure of Hf[ t BuNCH 2 CH 2 N- t Bu] 2 , which was synthesized along with its Zr congener from MCl 4 and Li 2 [ t BuNCH 2 CH 2 N + t Bu], reveals that it has an elongated tetrahedral geometry in the solid state.