Fabrication and Tunable Dielectric Properties of (Ba_0.7Sr_0.3)TiO₃‐Glass‐Based Thick‐Film Capacitors

Abstract

Ferroelectric glass-ceramics of composition 0.90 (Ba 0.7 Sr 0.3 ) TiO 3 -0.10(B 2 O 3 :SiO 2 ) (0.90 BST:0.10 BS) synthesized by sol-gel method have been used for the preparation of dielectric thick-film inks. The particle dispersion of the glass-ceramic powders in the thick-film ink formulations have been studied through rheological measurements for fabricating thick-film capacitors by screen printing technique. The thick films derived from such glass-ceramics are found to sinter at considerably lower temperatures than the pure ceramic, and exhibit good dielectric characteristics with a tunability of 32% at 1 MHz under a dc bias field of 35 kV/cm.

Dielectric behavior of perovskite glass ceramics

“…The thick film derived from BST glass-ceramics has tunability of 32 % at 1 MHz under a dc bias field of 35 kV/cm. This result indicates that such glass-ceramic composition have significant importance in the application of tunable phase shifter [135].…”

Fabrication and Dielectric Properties of (Ba0.7Sr0.3)TiO3–Glass Composites

“…A 35-m-thick film of the glass ceramic indicated n r of 32% at 35 kV/cm. 15) In most of these studies, however, few examinations were attempted to correlate the n r changes with some parameter of the fabricated BST-based materials.…”

“…It was also demonstrated that a thick-film sample fabricated from a glass powder with Ba/Sr = 7/3 had 27.3% tunability at 5 GHz under 10 kV/cm bias voltage. 23) It is interesting to note that BST glass-ceramic samples including those reported elesewhere 15,24,25) possess fairly good tunability even though they are not highly densified.…”

“…Barium strontium titanate, Ba x Sr 1-x TiO 3 (BST), is the most promising material for tunable microwave devices such as phase shifters, varactors, and tunable band filters, [4][5][6][7][8] owing to its high tunability and low dielectric loss at room temperature. Therefore, the fabrication and dielectric tunable properties of BST materials have been extensively studied in three different forms, i.e., bulk ceramics, [9][10][11] thick films, [12][13][14][15] and thin films. [16][17][18][19][20] Each form of BST material has its own specific issue.…”

“…Divya et al 15) In most of these studies, however, few examinations were attempted to correlate the n r changes with some parameter of the fabricated BST-based materials. Theoretically, the trend "the higher the dielectric constant, the higher the tunability" generally holds in an ideal ferroelectric where the dielectric response is controlled by the lattice dynamics of the material.…”