Some dielectric properties of electron-beam evaporated yttrium oxide thin films

Abstract

Thin films of yttrium oxide have been fabricated by the direct electron-beam evaporation, in an oxygen atmosphere, of 99.9% yttrium oxide powder. Such films, ranging in thickness from about 2000 Å to 15,000 Å, have been observed to be quite stable and free of pinholes over areas as large as 0.5 in. × 0.5 in. At 1000 Hz and 25 °C the lowest value of dielectric dissipation factor (tan δ) obtained was 0.00255, decreasing to a value of 0.0024 at 100 kHz. Bridge measurements on such films forming capacitors of the type AlY 2O 3Au further yielded an average dielectric permittivity value ε′ = 13.5 ± 1.5 and a temperature coefficient of capacitance of + 320 p.p.m./°C. Typical breakdown field strengths were in the order of 2.8 × 10 6 volt/cm for such capacitors as large as 0.065 μF, whilst the measured resistivity of the dielectric was estimated to be > 2 × 10 14 Ω cm .