Preparation of Al2O3 film by sol-gel method on thermally evaporated Al film

Sol-gel spin-coated Al2O3 film was deposited on quartz glass substrate with thermally evaporated Al film. Optical micrographs show that the Al film break forming perforated pinholes after the Al2O3 film was thermally processed. Pinholes on the film can be reduced by inserting a metal transition layer between the quartz glass substrate and the Al film but cannot be avoided after thermal process. Doping of scandium in evaporation aluminum cannot perfectly prevent the Al films from breaking and perforation. The breaking and perforation during the fabrication of the Al2O3 film can be dramatically reduced by heating the quartz glass substrate at 320 °C during thermal evaporation. The J-E curves show that the bottom Al electrode greatly affected the dielectric breakdown electric field.