Title :
Voltage and frequency dependent dielectric properties of BST-0.5 thin films on alumina substrates
Author :
Delprat, Sébastien ; Ouaddari, Mossaab ; Vidal, François ; Chaker, Mohamed ; Wu, Ke
Author_Institution :
INRS-Energie, Varennes, Que., Canada
fDate :
6/1/2003 12:00:00 AM
Abstract :
Dielectric properties of Ba/sub 0.5/Sr/sub 0.5/TiO/sub 3/ (BST-0.5) polycrystalline thin films, deposited on alumina substrates by means of reactive pulsed laser deposition (PLD), were measured at GHz frequencies using an interdigital capacitor (IDC). By applying a voltage up to 40 V between the two groups of fingers at room temperature, a high tunability of /spl sim/27% was achieved at 5 GHz. A relative dielectric constant of /spl sim/500 (consistent with the low-frequency IDC measurements) has been obtained using coplanar waveguides by means of the through-reflect-line (TRL) analysis combined with either a conformal mapping model or a full wave calculation. The BST loss tangent was estimated as /spl sim/0.05 in the range 3-16 GHz.
Keywords :
barium compounds; coplanar waveguides; dielectric losses; ferroelectric devices; ferroelectric thin films; microwave materials; permittivity; pulsed laser deposition; strontium compounds; 3 to 16 GHz; 40 V; 5 GHz; Ba/sub 0.5/Sr/sub 0.5/TiO/sub 3/; conformal mapping model; coplanar waveguides; ferroelectric thin films; frequency dependent dielectric properties; interdigital capacitor; loss tangent; polycrystalline thin films; reactive pulsed laser deposition; relative dielectric constant; through-reflect-line analysis; tunability; Dielectric measurements; Dielectric substrates; Dielectric thin films; Frequency dependence; Optical pulses; Pulse measurements; Pulsed laser deposition; Sputtering; Strontium; Voltage;
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2003.814091
