Download or read book Hydrothermal Processing of Barium Strontium Titanate Composites on Printed Circuit Board for Thin Film Varactor Applications written by and published by . This book was released on 2014 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film Ba0.7Sr0.3TiO3 has been deposited onto printed circuit boards at low temperatures for low and high frequency applications. The fabrication method involves spin coating sol-gel composites (a mixture of BST powder suspended in an amorphous BST sol), and treating the resultant films at 175°C. The treatment is done in an autoclave in an aqueous environment comprised of barium hydroxide, strontium hydroxide, and water, and is carried out at elevated temperature and pressure. This causes the amorphous BST sol to recrystallize, forming bridges that link the BST powders together, creating a dense network, leading to a higher dielectric constant. Three different types of powders have been explored for the composite. They are low-temperature derived, ceramic derived, and sol-gel derived powder. Low-temperature derived powders are the smallest in size, in the nanometer range. Due to such small sizes, the ferroelectric properties are lost, leading to no tunability and very low dielectric constant. The permittivity ranges from 30 to 55. Sol-gel derived powders are very reactive to the hydrothermal process. The resultant film permittivity is the highest, ranging from 200 to 260, but with a limited tunability of 1%. Ceramic derived powders are compatible with the process. The permittivity is less than that of sol-gel derived, with values from 130 to 140, but the tunability ranges from 4 to 8% at low frequencies (500 kHz to 20 MHz). For high frequency characterization (45 MHz to 1.15 GHz), films containing ceramic derived powder are deposited onto grounded coplanar waveguide capacitors. The dielectric constant significantly reduced, reaching as low as 18, but tunability increased to 18%.
Download or read book Hydrothermal Synthesis of Barium Strontium Titanate bst Powders and Continuous and Patterned Thin Films written by Xuezheng Wei and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium strontium titanate (BST) solid-solution oxides represent an important class of ferroelectric materials due to their high dielectric constants, composition dependent Curie temperature, and potential applications in dynamic random access memory (DRAM). Hydrothermal technique is a new low-temperature (
Download or read book Processing and electrical characterization of barium strontium titanate thin films for ULSI DRAM application written by Shylaja Katakam and published by . This book was released on 1998 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Barium Strontium Titanate Films for Tunable Microwave and Acoustic Wave Applications written by Venkataramanan Gurumurthy and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The composition-dependent Curie temperature and bias-dependant dielectric permittivity of Barium Strontium Titanate (BST) makes it very attractive for tunable application in the RF/Microwave regime. In this research work, the performance of BST varactors fabricated on the conventional Pt/Ti/SiO2/Si bottom electrode stack were compared with those fabricated using chemical vapor deposited Nanocrystalline Diamond (NCD) as the diffusion barrier layer instead of SiO2. The varactors fabricated on NCD films displayed much better symmetry in capacitance-voltage behavior and better overall quality factors than varactors fabricated on SiO2. The improvement in performance can be attributed to existence of stable interfaces in the devices fabricated on NCD which reduced the bottom electrode losses at high frequencies. The SiO2 based BST varactors on the other hand displayed better reliability and breakdown fields. The main purpose of this research work is to develop a robust Metal Insulator Metal (MIM) structure to achieve better all round performance of BST varactors. In the second part of this research work, the prospect of developing diamond based layered Surface Acoustic Wave (SAW) devices using Ba0.8Sr0.2TiO3 as the piezoelectric layer is investigated. Structural characterization of BST thin films deposited on Si/NCD/Pt and Si/SiO2/Ti/Pt stack were performed using X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM). Cross-sectional studies on the two stacks were performed using Scanning Electron Microscopy (SEM). X-Ray Mapping (XRM) was then done to ascertain the quality of the interfaces and to check for interdiffusion between layers. MIM structures in the Coplanar Waveguide (CPW) configuration were fabricated using conventional lithography and etching techniques for high frequency measurements. The performance of the fabricated varactors was characterized from 100 MHz to 1 GHz. For the SAW application, structural characterization of Ba0.8Sr0.2TiO3 on Chemical Vapor Deposited (CVD) diamond was done and the deposition procedure was optimized to obtain thick BST films. SAW bandpass filters and resonators were designed wherein the device geometry was varied over a wide range in order to characterize the variation in device performance with geometry. Finally interdigital capacitor structures were fabricated and used for conducting Curie temperature measurements on the deposited BST films in order to determine the operation range of the deposited BST films.
Download or read book Synthesis Characterization and Applications of Barium Strontium Titanate Thin Film Structures written by Supriya Ashok Ketkar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium Strontium Titanate (BST) based ferroelectric thin film devices have been popular over the last decade due to their versatile applications in tunable microwave devices such as delay lines, resonators, phase shifters, and varactors. BST thin films are promising candidates due to their high dielectric constant, tunability and low dielectric loss. Dielectric-tunable properties of BST films deposited by different deposition techniques have been reported which study the effects of factors, such as oxygen vacancies, film thickness, grain size, Ba/Sr ratio, etc. Researchers have also studied doping concentrations, high temperature annealing and multilayer structures to attain higher tunability and lower loss. The aim of this investigation was to study material properties of Barium Strontium Titanate from a comprehensive point of view to establish relations between various growth techniques and the film physical and electrical properties. The primary goal of this investigation was to synthesize and characterize RF magnetron sputtered Barium Strontium Titanate (Ba1-xSrxTiO3), thin film structures and compare their properties with BST thin films deposited by sol-gel method with the aim of determining relationships between the oxide deposition parameters, the film structure, and the electric field dependence. In order to achieve higher thickness and ease of fabrication, and faster turn around time, a [grave]stacked' deposition process was adopted, wherein a thin film (around 200nm) of BST was first deposited by RF magnetron sputtering process followed by a sol-gel deposition process to achieve higher thickness. The investigation intends to bridge the knowledge gap associated with the dependence of thickness variation with respect to the tunability of the films. The film structures obtained using the three different deposition methods were also compared with respect to their analytical and electrical properties.
Download or read book Hydrothermal Processing of Barium Titanate Ceramics and Thin Films written by Ilias Nikolaidis and published by . This book was released on 2004 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Performance Barium Strontium Titanate Varactor Technology for Microwave Circuit Applications written by Baki Acikel and published by . This book was released on 2002 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Barium Strontium Titanate Thin Film Base Multi Layer Structures for Microwave Application written by Kumaravinothan N. Sanmugaratna Sarma and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Nonstoichiometry of Barium Strontium Titanate Thin Films for Dram Applications written by and published by . This book was released on 1999 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we investigate the microstructural accommodation of nonstoichiometry in (Ba(subscript x)Sr{sub 1-x}Ti{sub 1+y}O{sub 3+z}) thin films grown by chemical vapor deposition. Films with three different (Ba+Sr)/Ti ratios of 49/51 (y=0.04 in the notation of the formula above), of 48/52 (y=0.08) and of 46.5/53.5 (y=O.15), were studied. High-resolution electron microscopy is used to study the microstructure of the BST films. High-spatial resolution electron energy-loss spectroscopy (EELS) is used to reveal changes in chemistry and local atomic environment both at grain boundaries and within grains as a function of titanium excess. We find an amorphous phase at the grain boundaries and grain boundary segregation of excess titanium in the samples with y=0.15. In addition, EELS is also used to show that excess titanium is being partially accommodated in the grain interior. Implications for the film electrical and dielectric properties are outlined.
Download or read book Processing Science of Barium Titanate written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium titanate and barium strontium titanate thin films were deposited on base metal foils via chemical solution deposition and radio frequency magnetron sputtering. The films were processed at elevated temperatures for densification and crystallization. Two unifying research goals underpin all experiments: 1) To improve our fundamental understanding of complex oxide processing science, and 2) to translate those improvements into materials with superior structural and electrical properties. The relationships linking dielectric response, grain size, and thermal budget for sputtered barium strontium titanate were illustrated. (Ba0.6Sr0.4)TiO3 films were sputtered on nickel foils at temperatures ranging between 100-400 Ã'°C. After the top electrode deposition, the films were co-fired at 900 Ã'°C for densification and crystallization. The dielectric properties were observed to improve with increasing sputter temperature reaching a permittivity of 1800, a tunability of 10:1, and a loss tangent of less than 0.015 for the sample sputtered at 400 Ã'°C. The data can be understood using a brick wall model incorporating a high permittivity grain interior with low permittivity grain boundary. However, this high permittivity value was achieved at a grain size of 80 nm, which is typically associated with strong suppression of the dielectric response. These results clearly show that conventional models that parameterize permittivity with crystal diameter or film thickness alone are insufficiently sophisticated. Better models are needed that incorporate the influence of microstructure and crystal structure. This thesis next explores the ability to tune microstructure and properties of chemically solution deposited BaTiO3 thin films by modulation of heat treatment thermal profiles and firing atmosphere composition. Barium titanate films were deposited on copper foils using hybrid-chelate chemistries. An in-situ gas analysis process was developed to probe the organic removal and.
Download or read book Microstructure and Electrical Property Characterization of Barium Strontium Titanate Thin Films Prepared by a Sol gel Technique for Dram Capacitor Applications written by Danielle Marie Tahan and published by . This book was released on 1997 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrothermal Synthesis of Barium Strontium Titanade BST Powders and Continuous and Patterned Thin Films written by Xuezheng Wei and published by . This book was released on 2004 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Processing and Structural Studies of Barium Strontium Titanate BaxSr1 xTiO3 Using the High Temperature Hydrothermal Technique written by Khairunisak Abdul Razak and published by . This book was released on 2007 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Barium Strontium Titanate written by Natheer Mahmood and published by LAP Lambert Academic Publishing. This book was released on 2014-03 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium Strontium Titanate Ba(x)Sr(1-x)TiO3 Is a solid solution between BaTiO3 and SrTiO3 which posses different Ferroelectric Curie temperature, Barium Strontium Titanate (BST) posses an adjustable value of Ferroelectric Curie temperature Tc depending on the value of (x). BST has wide range of applications depending on Curie temperature and Dielectric properties . BST used in communications especially in microwave tunable circuits, phase shifter, waveguides, antennas, MOSFET, MLCCs and Varactor.
Download or read book Growth and Characterization of Barium Strontium Titanate Thin Films with Enhanced Electrical Properties Using Pulsed Laser Deposition written by Anuranjan Srivastava and published by . This book was released on 1999 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Barium Strontium Zirconate Titanate Thin Films and Their Microwave Device Applications written by Ngai-yui Chan and published by . This book was released on 2010 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Dispersant on Preparation of Barium Strontium Titanate Nanopowders by Microwave Hydrothermal Processing written by and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
