Sequential grafting of dielectric phosphates onto silicon oxide

This work explores the growth of high-k oxide films deposited onto silicon by original synthesis methods based on wet chemistry, either aqueous or organic. Zirconium and titanium phosphate layers have been deposited by alternate dipping sequences in diluted solutions of monomeric Ti or Zr alkoxides (M) and phosphoric acid (P). The films have been characterized by dynamic contact angle measurements with water, infrared spectroscopy, X-ray reflectometry, HRTEM microscopy, and Rutherford backscattering spectroscopy. The composition of the zirconium phosphate films corresponds to a P/Zr = 1 ratio, induced by the dipping sequence, and not to that defined by thermodynamic conditions that would precipitate a P/Zr = 2 composition. The growth rate shows that, in optimized conditions, dense monolayers can be deposited during each cycle. The dielectric properties indicate a high dielectric constant that decreases p Z, upon dehydration at 300 degrees C. The static dielectric constant measured at 1 kHz in capacitance-voltage geometry is around 40 for the films heat-treated at 300 degrees C in air.