Electrical Properties of Thin-Film Capacitors Fabricated Using High Temperature Sputtered Modified Barium Titanate

Materials

Glyn J. Reynolds²  Martin Kratzer¹  Martin Dubs¹  Heinz Felzer¹ 

[1] OC Oerlikon Balzers AG, Business Unit Systems, Iramali 18, P.O. Box 1000, Balzers LI-9496, Liechtenstein; E-Mails:;Oerlikon USA, Inc., Business Unit Systems, 970 Lake Carillon Dr, Suite 300, St. Petersburg, FL 33716,USA

关键词: thin film capacitors;    barium titanate;    high-k;   

DOI  :  10.3390/ma5040644

来源: mdpi

【 摘 要 】

Simple thin-film capacitor stacks were fabricated from sputter-deposited doped barium titanate dielectric films with sputtered Pt and/or Ni electrodes and characterized electrically. Here, we report small signal, low frequency capacitance and parallel resistance data measured as a function of applied DC bias, polarization versus applied electric field strength and DC load/unload experiments. These capacitors exhibited significant leakage (in the range 8–210 μA/cm²) and dielectric loss. Measured breakdown strength for the sputtered doped barium titanate films was in the range 200 kV/cm −2 MV/cm. For all devices tested, we observed clear evidence for dielectric saturation at applied electric field strengths above 100 kV/cm: saturated polarization was in the range 8–15 μC/cm². When cycled under DC conditions, the maximum energy density measured for any of the capacitors tested here was ~4.7 × 10⁻² W-h/liter based on the volume of the dielectric material only. This corresponds to a specific energy of ~8 × 10⁻³ W-h/kg, again calculated on a dielectric-only basis. These results are compared to those reported by other authors and a simple theoretical treatment provided that quantifies the maximum energy that can be stored in these and similar devices as a function of dielectric strength and saturation polarization. Finally, a predictive model is developed to provide guidance on how to tailor the relative permittivities of high-k dielectrics in order to optimize their energy storage capacities.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.