A Study of CVD Growth Kinetics and Film Microstructure of Zirconium Dioxide from Zirconium Tetra-tert-Butoxide

The chemical vapor deposition (CVD) of polycrystalline zirconium dioxide (ZrO 2 ) from zirconium tetra- tert -butoxide {Zr[OC(CH 3 ) 3 ] 4 } is described. The ZrO 2 films, which were deposited on Si(100), were characterized by scanning electron microscopy, ellipsometry, X-ray diffraction, Rutherford backscattering spectrometry, and Auger electron spectroscopy. Deposition was studied between 380 and 825 °C, and at precursor pressures between 4 × 10 - 5 and 1 × 10 - 4 Torr. Film microstructure depends on deposition temperature, with low temperatures (<420 °C) leading to the formation of nearly equi-axed grains, moderate temperatures (450−550 °C) producing oblate grains, and high temperatures (>700 °C) giving rise to triangular grains. Film density decreases with increasing deposition temperature. The kinetics for steady-state ZrO 2 growth were studied as functions of temperature and precursor pressure. Results were fit to a two-step kinetic model involving reversible precursor adsorption followed by irreversible decomposition to ZrO 2 . The induction period ( t i ) to growth was measured as a function of temperature for a single precursor pressure (9.4 × 10 - 5 Torr); t i decreases with temperature from 490 s at 381 °C to less than 1 s at 743 °C.