| 摘要 |
PURPOSE:To obtain a silicon oxide film having an improved dielectric breakdown strength, by causing the silicon oxide film to contain a metal element which is easily trapped in the silicon oxide film in a specific range of concentration. CONSTITUTION:A silicon wafer 11, which is an N type wafer having a specific resistance 3-6OMEGA.cm, is heat oxidized in the oxygen atmosphere at 1,000 deg.C, whereby 300Angstrom silicon oxide film 12 is formed. Fe is mixed in the oxygen supplied into an oxidation furnace so that the Fe is introduced into the silicon oxide film 12 in the range of a concentration 1X10<16>-1X10<19>atm/cm<3>. The yield of the element is thereby improved to be about 30% or more when an external voltage is applied thereto such that the field strength within the silicon oxide film is 8MV/cm. If Cr is introduced into the silicon oxide film so as to have a mean concentration 1X10<16>-1X10<19>atm/cm<3>, the dielectric breakdown strength of the silicon oxide film is improved.
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