Radio frequency dielectric dissipation measurements on yttrium oxide thin films

Abstract

The dielectric dissipation factor (tan δ) of evaporated thin film Al-Y 2-O 3-Au capacitors has been measured in the frequency range 1 kHz-40 MHz. The yttrium oxide films (≈ 5000 Å) were fabricated by the direct electron-beam evaporation of 99.9% Y 2O 3 powder. The geometry of these capacitors (≈ 40 pF) deposited on alumina substrates provided large contact pads for direct attachment to the measuring bridges. Lead inductance was minimal while lead and contact resistance was less than 0.2 ω. Tan δ measurements were made at 20°C with a capacitance bridge, a Wayne Kerr bridge and a Q-meter at appropriate frequencies. At 1 kHz, tan δ values of various specimens varied from 0.004–0.009. These values decreased rapidly with increasingly frequency, however, to a resistance-corrected constant value tan δ≦0.004 over the range 100 kHz-40 MHz.