Tunability, Frequency and Temperature Behavior of Cofired LTCC-Integrated Barium-Strontium-Titanate up to 8 GHz

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000447-000454
Author(s):  
Sven Rentsch ◽  
Jens Müller ◽  
Matthias Hein
Keyword(s):  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Microwave Properties ◽  
Specific Procedure ◽  
Electrical Field ◽  
New Approach ◽  
Barium Strontium ◽  
Bst Films ◽  
Effects Of Temperature ◽  
Shunt Capacitor

A new approach towards embedding barium-strontium-titanate (BST) patches into a commercial low temperature co-fired ceramic (LTCC) is described, using a tape transfer technique. Pressure-assisted sintering is successfully employed to achieve flat multi-layer multi-material modules without internal cracks or delaminations. Beside the description of the processing technology, the paper presents also a specific procedure of determining the microwave properties of embedded thick BST films, which is based on using the experimental evaluation of a shunt capacitor. The permittivity of the embedded BST determined at room temperature is about 214 and remains constant at least from 100 MHz up to 8 GHz. In addition, the effects of temperature and bias voltages on the microwave properties of LTCC BST were studied systematically from 1 MHz up to 8 GHz. We observed a tuning of the permittivity by about −49 %, either by raising the temperature from 21°C to 125°C, or by applying a bias electrical field of up to 10 V/μm. Additionally, breakdown voltages were investigated. The embedded BST withstands field strengths of more than 20 V/μm under laboratory conditions.

Tunability, Frequency, and Temperature Behavior of Cofired LTCC-Integrated Barium-Strontium-Titanate Shunt Capacitors up to 8 GHz

2013 ◽  
Vol 10 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Sven Rentsch ◽  
Jens Müller ◽  
Matthias Hein
Keyword(s):  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Microwave Properties ◽  
Electrical Field ◽  
New Approach ◽  
Barium Strontium ◽  
Bst Films ◽  
Effects Of Temperature ◽  
Shunt Capacitors ◽  
Shunt Capacitor

A new approach toward embedding barium-strontium-titanate (BST) patches into a commercial low temperature cofired ceramic (LTCC) is described, using a tape transfer technique. Pressure-assisted sintering is successfully employed to achieve flat multilayer multimaterial modules without internal cracks or delaminations. Apart from the description of the processing technology, the paper also presents a specific procedure of determining the microwave properties of embedded thick BST films, which is based on using the experimental evaluation of a shunt capacitor. The permittivity of the embedded BST determined at room temperature is about 214 and remains constant at least from 100 MHz up to 8 GHz. In addition, the effects of temperature and bias voltages on the microwave properties of LTCC BST were studied systematically from 1 MHz up to 8 GHz. We observed a tuning of the permittivity by about −49%, either by raising the temperature from 21°C to 125°C, or by applying a bias electrical field of up to 10 V/μm. Additionally, breakdown voltages were investigated. The embedded BST withstands field strengths of more than 20 V/μm under laboratory conditions.

Effects of thermal misfit strains on dielectric features of sandwich barium strontium titanate multilayer thin films on metal plates

2021 ◽  
pp. 2150030
Author(s):  
Hanting Dong ◽  
Liang Ke ◽  
Xiangjun Hui ◽  
Jiangfeng Mao ◽  
Haiqing Du ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Composition Range ◽  
Multilayer Films ◽  
Multilayer Thin Films ◽  
Barium Strontium ◽  
Metal Plates ◽  
Bst Films

Effects of thermal misfit strains on dielectric features for sandwich structural barium strontium titanate (BST) thin films on metal plates were investigated via a modified thermodynamic model. When TEC of substrates is closer to that of BST, larger permittivity and tunability can be received. The tendency of permittivities and tunabilities of such films as a function of TEC of substrates agrees with that of single compositional BST films and compositionally graded BST multilayer films. The highest tunability reaches 60% at the biasing field of 300 kV/cm when the films are onto Ti metal. Moreover, Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3 structure can obtain higher tunability than Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3 structure, while Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3/Ba[Formula: see text]Sr[Formula: see text]TiO3 films show better compatible composition range for relatively larger tunability. Dielectric properties of sandwich-like BST films in some references can also be analyzed based on our calculated results.

Effect of Annealing Temperature on the Microstructure of Barium Strontium Titanate Films

2008 ◽  
Vol 368-372 ◽  
pp. 56-58
Author(s):  
Jia Xuan Liao ◽  
En Qiu Li ◽  
Zhong Tian ◽  
Jiang Xu ◽  
Hai Guang Yang
Keyword(s):  
Magnetron Sputtering ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Annealing Temperature ◽  
Structural Characteristics ◽  
Rf Magnetron Sputtering ◽  
Surface And Interface ◽  
Barium Strontium ◽  
Bst Films

Barium strontium titanate (Ba1−xSrxTiO3, BST) films have been prepared on Pt/Ti/SiO2/Si by medium frequency (MF) magnetron sputtering, and subsequently in situ crystallized at 500-700°C. The microstructures of the MF-BST films are studied. BST films prepared by radio frequency (RF) magnetron sputtering and exhibited preferential (110) orientation, are compared. XRD shows that the MF-BST films exhibit preferential (111) orientation and better crystallization than the RF-BST films at the same annealing temperature. AFM displayed that the MF-BST films were smooth and compact. XPS analysis exhibited that the MF-BST films revealed better surface and interface structural characteristics. Their dielectric properties were also compared.

Sign in / Sign up

Export Citation Format

Share Document