Fabrication and Characterization of High Temperature Film Capacitors (PREPRINT)

Capacitors that perform well at temperature exceeding 150 deg C and have energy densities in excess of 1 Jcc are an enabling technology for many applications in automotive, geophysical exploration, aerospace, and the military. To address this need Nanohmics has produced temperature-stable film capacitors using amorphous silicon dioxide as the dielectric material. The capacitors are fabricated by depositing submicron films of silicon dioxide on both sides of a thin metalized poylimide substrate to form dielectric-coated electrodes. Next, two coated electrodes are wound together into a cylindrical shape to produce the capacitor core. Electrical contact is then made to the ends of the cores and electrical wires are attached to the contacts. Measurements indicate that capacitors with amorphous silicon dioxide dielectric have fairly stable capacitance, dissipation factor, and breakdown threshold over a wide temperature range. In this paper Nanohmics presents test results that show1-2 micron film capacitors fabricated using SiO2 dielectric have stable properties over a wide temperature range and a lifetime in excess of 1,000 hours at temperature of 200 deg C under applied voltages from 50 to 75 VDC.