Fabrication Alumina Film with High Breakdown Field Strength by New Aerosol Gas Deposition Technology

Abstract

The aerosol gas deposition (AGD) is a low temperature method for film formation. No heating procedure exists in the AGD process during the formation of the AGD films, where even ceramic films can be fabricated. We have demonstrated the advanced AGD with the practical application of a room temperature film-forming device for ceramics that can form a thin insulating film with excellent electrical insulation at a high deposition rate. For example, an alumina film having a withstand voltage of 5 kV with a film formation of about 300 mm round area is required. In order to obtain such a high dielectric breakdown electric field strength, it is necessary to form a homogeneous film in which alumina particles are densely bonded. In this report the conventional AGD system has been improved and a new target AGD has been developed. The deposition has been performed by the arrival of active species (atoms, molecules and fine nanoparticles) along the target surface. In order to handle homogeneous large areas and high-speed film formation, a new mask plate was added for cutting flying particles in specular direction. Good alumina film quality was obtained by the new target AGD added the mask plate using 30 mm wide nozzle.