Zirconium oxide CVD on Si(100) from zirconium tetra-tert-butoxide: growth kinetics and film microstructure

摘要

The CVD of zirconium dioxide (ZrO_2) films from zirconium tetra-tert-butoxide {Zr[OC(CH_3)_3]_4} is described. The films, which were deposited on Si(100), were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ellipsometry, X-ray diffraction (XRD), and Rutherford backscattering spectroscopy (RBS). 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. Density decreases with increasing deposition temperature. The kinetics for steady-state 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 to growth was measured as a function of temperature.