Facile synthesis of AlOx dielectrics via mist-CVD based on aqueous solutions

Aluminum oxide (AlOx) thin films were synthesized by mist-chemical vapor deposition (mist-CVD) using aluminum acetylacetonate (Al(acac)3) dissolved in an aqueous solvent mixture of acetone and water. Nitrogen gas was used to purge the precursor solution and growth rates between 7.5-13.3 nm/min were achieved at substrate temperatures of 250-350 °C. The AlOx layers deposited at temperatures below 350 °C exhibit 3-5 at% residual carbon levels, however those grown at 350 °C exhibit only 1-2 at% carbon impurity. Reasonable dielectric properties were obtained in the latter, with a dielectric constant (κ) of ~ 7.0, breakdown field of ~ 9 MV/cm and relatively low leakage current density of ~ 8.3×10−10 A/cm2.