Ferroelectric Na0.5K0.5NbO3 Films for Voltage Tunable Microwave Devices

2000 ◽  
Vol 656 ◽  
Author(s):  
Choong-Rae Cho ◽  
Alex Grishin ◽  
Johanna Andrèasson ◽  
Ture Lindbäck ◽  
Saeed Abadei ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Phase ◽  
Microwave Frequency ◽  
Dissipation Factor ◽  
Si Substrate ◽  
Applied Bias ◽  
Tunable Microwave Device ◽  
Oxide Substrates ◽  
Tunable Microwave ◽  
Device Applications

ABSTRACTSingle phase Na0.5K0.5NbO3 (NKN) thin films have been pulsed laser deposited on Al2O3(0112), LaAlO3(001), and MgO(001) single crystal substrates as well as on the SiO2/Si(001) wafers to demonstrate films feasibility for voltage tunable microwave device applications. NKN film texture has been found to be quite different on three different single crystals: highly c-axis oriented on Al2O3, “cube-on-cube” epitaxial quality on LaAlO3, bi-axial textures on MgO, while NKN films grown on Si substrate with various thickness of SiO2 buffer layer possess highly c-axis oriented quadrupled structure. NKN film interdigital capacitors fabricated onto single crystal oxide substrates showed tunability of 30-40 % and dissipation factor of 0.01-0.02 at 1 MHz and applied electric field of 100kV/cm. Microwave frequency measurements for NKN/Si varactors yield 13 % tunability and dielectric loss tanδ as low as 0.012 at 40 GHz under 200 kV/cm applied bias.

Thin Na0.5K0.5NbO3 Films for Varactor Applications

2000 ◽  
Vol 623 ◽  
Author(s):  
C.-R. Cho ◽  
J.-H. Koh ◽  
A. Grishin ◽  
S. Abadei ◽  
P. Petrov ◽  
...  
Keyword(s):  
Microwave Frequency ◽  
Dissipation Factor ◽  
Leakage Currents ◽  
Low Frequencies ◽  
Si Substrates ◽  
Low Dielectric ◽  
Low Leakage ◽  
Tunable Microwave Device ◽  
Device Applications ◽  
Spectroscopy Studies

AbstractSingle phase Na0.5K0.5NbO3 (NKN) thin films have been pulsed laser deposited on SiO2/Si(C-01) wafers and LaAlO3(001) and MgO(001) single crystals. Radio frequency (up to 1 MHz) and microwave (up to 50 GHz) dielectric spectroscopy studies have been carried out to characterize thin NKN films for electrically tunable microwave device applications. Films on single crystal oxide substrates showed tunabilities as high as 30-40 % at 40 V bias and dissipation factor of 0.01-0.02 at 1 MHz. The films on Si substrates showed low dielectric losses of < 0.01, and low leakage currents. Dielectric properties of ferroelectric films on Si substrates at low frequencies are greatly influenced by the depletion capacitance and the resistance inserted by semiconductor substrate. Microwave frequency measurements for NKN film on Si wafers yield more than 10 % tunability at 50 GHz and loss tan σ <0.1 at 10 GHz.

Correlation between magnetic properties of layered ferromagnetic/dielectric material and tunable microwave device applications

2002 ◽  
Vol 91 (8) ◽  
pp. 5449-5455 ◽  
Author(s):  
Erwan Salahun ◽  
Patrick Quéffélec ◽  
Gérard Tanné ◽  
Anne-Lise Adenot ◽  
Olivier Acher
Keyword(s):  
Magnetic Properties ◽  
Dielectric Material ◽  
Microwave Device ◽  
Tunable Microwave Device ◽  
Tunable Microwave ◽  
Device Applications

Electrophoretic Deposition Ba0.65Sr0.35TiO3 Thick Films for Tunable Microwave Devices

2007 ◽  
Vol 336-338 ◽  
pp. 111-113
Author(s):  
Hao Xue ◽  
Chen Ai ◽  
Wei Zhao ◽  
He Ping Zhou
Keyword(s):  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Electrophoretic Deposition ◽  
Thick Films ◽  
Dielectric Constants ◽  
Barium Strontium ◽  
Tunable Microwave Device ◽  
Metal Insulator Metal ◽  
Tunable Microwave ◽  
Device Applications

Pure barium strontium titanate (Ba0.65Sr0.35TiO3) and MnO2-modified barium strontium titanate (Ba0.65Sr0.35TiO3-MnO2) thick films were fabricated by electrophoretic deposition technique. The structures and morphologies of the films were analyzed. The dielectric measurements were conducted on metal-insulator-metal capacitors using platinum as the bottom electrodes and gold as the top electrodes. The dielectric constants and dissipation factors of Ba0.65Sr0.35TiO3 and Ba0.65Sr0.35TiO3-15wt% MnO2 thick films were measured at a frequency of 1 MHz. The tunabilities of 12.5% and 9.3% were obtained for Ba0.65Sr0.35TiO3 and Ba0.65Sr0.35TiO3-MnO2 thick films under an applied electric field of 15 kV/cm, respectively. The dielectric properties of the present thick films were suitable for tunable microwave device applications.

Fabrication and Electrical Characterization of Ba(1-x)SrxTiO3 Based Thin Films

2003 ◽  
Vol 784 ◽  
Author(s):  
E. Ngo ◽  
W. D. Nothwang ◽  
C. Hubbard ◽  
M. W. Cole ◽  
W. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Low Frequency ◽  
Pulsed Laser ◽  
Electrical Characterization ◽  
Microwave Frequency ◽  
Thin Film Deposition ◽  
Dissipation Factor ◽  
Film Deposition ◽  
Device Applications

ABSTRACTOver the past several years there has been a tremendous growth and development of thin film deposition technology in the electronics industry. Ferroelectric thin films have been recognized for their unique dielectric properties and appear to be desirable for tunable microwave device applications. Among the most promising candidates for such applications are Ba(1−x)SrxTiO3[BST] and BST-based thin films. In this work pure BST and acceptor doped BST-based thin films were fabricated on (100) MgO substrates via pulsed laser deposition [PLD]. X-ray diffraction (XRD) in conjunction with the atomic force microscope (AFM) were used to analyze the film crystalinity and surface morphology. The dielectric properties were characterized at both 100 kHz and 20 GHz. The MIM capacitor configuration was used to attain the dielectric properties at 100 kHz and the microwave measurements, S11 reflection parameters, were achieved via interdigitated capacitor design with Au/Ag top electrodes. The parallel resistor-capacitor models were used to determine the microwave capacitance and Q factors and the permittivity was calculated using a modified conformal-mapping partial-capacitance method using the dimension of the capacitors. Our results demonstrated that the low frequency and microwave frequency dielectric properties were strongly influenced by the film composition. Specifically, the Mg doping served to lower the dissipation factor, permittivity, and tunability of the BST based films at both frequencies. This work demonstrates that the BST based thin films possessed excellent microstructural, structural, and dielectric properties. The structure-process-property correlations of the pulsed laser deposited BST and acceptor doped BST-based thin films are discussed in detail.

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