Title

Linearity and temperature dependence of large area processed high Q BST varactors

Document Type

Article

Publication Date

7-2010

Publication Source

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Abstract

Ba0.6Sr0.4TiO3 (BST) thin-films with large dielectric tunability as high as 4:1 were obtained using a large-area pulsed laser deposition process, with low loss-tangents below 0.01 at zero-bias and 10 GHz. This paper summarizes experimental results obtained on large-area processed BST thin films on 100-mm-diameter sapphire substrates characterized using a varactor shunt switch test structure. Varactors with 0.25-μm-thick BST films exhibited large dielectric tunability, the relative dielectric permittivity at zero bias of 990 tuned to 250 at an electric field of 320 kV/cm. The leakage current through the BST film was below 2 nA up to 6 V dc bias. The quality factor (Q) exceeded 300 at relatively low 6 V dc bias for the BST varactors at 1 GHz. These results confirm that large-area processed BST thin films are ready to compete with semiconductor varactors for commercial applications at RF, microwave, and millimeterwave frequencies.

Inclusive pages

1692 - 1695

ISBN/ISSN

0885-3010

Comments

Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting or republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.

Publisher

IEEE

Volume

57

Issue

7

Peer Reviewed

yes

Keywords

barium compounds;dielectric losses;leakage currents;permittivity;pulsed laser deposition;strontium compounds;thin film capacitors;varactors;Al2O3;BST thin-films;BST varactors;Ba0.6Sr0.4TiO3;dielectric tunability;frequency 1 GHz;frequency 10 GHz;high-Q barium strontium titanate thin-film varactors;leakage current;loss-tangents;pulsed laser deposition process;relative dielectric permittivity;sapphire substrates;semiconductor varactors;size 0.25 mum;size 100 mm;varactor shunt switch test structure;zero-bias;Barium;Binary search trees;Dielectric substrates;Dielectric thin films;Linearity;Strontium;Temperature dependence;Titanium compounds;Transistors;Varactors