Physical properties of (Ba,Sr)TiO/sub 3/ thin films used for integrated capacitors in microwave applications

Influence of Substrate Bias on the Structural and Dielectric Properties of Magnetron-Sputtered BaxSr1-xTiO3Thin Films

“…It has been previously reported that films with a low (Ba + Sr)/Ti ratio exhibit low dielectric permittivity, high quality factors, and low dielectric tunability. 6,8,12 This agrees well with our experiments where an increase of the (Ba + Sr)/Ti ratio at substrate bias of 60 V correlates with an increase of the relative dielectric permittivity to a bulk-like value of 780 at room temperature, an increase of the dielectric tunability to 55%, and a decrease of the quality factor. Also, the large discrepancy between the relative dielectric permittivity of the BST films grown at lower substrate bias (350 -410) and the calculated bulk value for the measured Ba content of x = 0.24 (about 600) can be explained by an excess of Ti in the BST films.…”

“…High quality polycrystalline BST capacitors have been grown by magnetron sputtering 5,6 , chemical vapor deposition 7,8 , sol gel 4,9 , pulsed laser deposition 10,11 and other methods and the dependence of the dielectric properties on deposition temperature, growth rate, process pressure, composition, and film thickness has been reported 5,6,8,12,13 . The properties of BST thin films are usually inferior to their bulk analogs due to grain size effects, charged defects, the formation of interface layers, and the build-up of lattice strain.…”

Electrical Properties of Textured Niobium‐Doped Bismuth Titanate Ceramics

“…In the middle of the ball milling, 5 wt% (on the dry weight basis) polyvinyl alcohol (99.6%, Vetec Química Fina Ltda, Duque de Caxias, Brazil) and 2.5 wt% (on the dry weight basis) glycerin (99.5%, Cromoline Química Fina Ltda, Diadema, Brazil) were added as a binder and a plasticizer, respectively. The slurry was ball milled for 24 h. The Bi 4 Ti 3 O 12 platelets (5 wt% of the fine powder) were added and mixed with the Bi 4 Ti 3 O 12 slurry under electromagnetic stirring for 4 h. Finally, the slurry was degassed under vacuum and tape cast on a glass surface at a speed of 0.5 cm/s and a single doctor blade opening of 120 μm . The tapes obtained were dried at room temperature, cut into pieces of 5 mm 2 , stacked, and laminated at a pressure of 80 MPa for 10 min at 150°C.…”

Thin fim barium strontium titanate capacitors for tunable RF frond-end applications

“…Figure 2.4 -The results are based on a literature survey on the performance of dielectric parallel plate MIM varactors in terms of Q and η. The solid line is a fit to the best reported measurement results of ferroelectric varactors (BaxSr1−xTiO3 (BST), squares) at 1 MHz [40][41][42][43][44][45][46][47][48]. Data of BST for 1-10 GHz are plotted as diamonds [40,41].…”

“…Data on thin film ferroelectrics, using different deposition techniques, which have resulted in a high tunability and low losses were collected for parallel plate MIM capacitors at 1 MHz for Ba x Sr 1−x TiO 3 (BST) [40][41][42][43][44][45][46][47][48]. Data of BST between 1-10 GHz is given in [40] and [41].…”