Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387843
K. Lam, X.X. Wang, H. Chan
Bismuth sodium barium titanate [(Bi0.5Na0.5)0.94Ba0.06TiO3 or BNBT6] ceramic powder have been incorporated into a polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE) 70/30 mol%] copolymer matrix to form 0-3 composites. With the composition near the morphtrophic phase boundary (MPB) region, BNBT6 has relatively high piezoelectric properties. Polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE)] is a ferroelectric copolymer that has high piezoelectric and pyroelectric performance. BNBT6/P(VDF-TrFE) 0-3 composites with BNBT6 volume fraction Phi ranging from 0.05 to 0.3 were prepared using solvent casting to disperse the ceramic powder in the copolymer matrix followed by hot-pressing. The pyroelectric coefficient of the composites was measured as a function of Phi under different A.C. poling conditions. As both the BNBT6 inclusion and P(VDF-TrFE) matrix can be poled under similar conditions, the composites can be poled effectively after subjected to several cycles of sinusoidal electric field. The BNBT6 0-3 composites (poled with a.c. source) were found to have better pyroelectric properties than that of lead zirconate titante PZT / P(VDF-TrFE) 0-3 composites (poled with d.c. source).
{"title":"(Bi0.5Na0.5)0.94Ba0.06TiO3 / P(VDF-TrFE) 0-3 Composites Poled with a Sinusoidal Electric Field","authors":"K. Lam, X.X. Wang, H. Chan","doi":"10.1109/ISAF.2006.4387843","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387843","url":null,"abstract":"Bismuth sodium barium titanate [(Bi0.5Na0.5)0.94Ba0.06TiO3 or BNBT6] ceramic powder have been incorporated into a polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE) 70/30 mol%] copolymer matrix to form 0-3 composites. With the composition near the morphtrophic phase boundary (MPB) region, BNBT6 has relatively high piezoelectric properties. Polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE)] is a ferroelectric copolymer that has high piezoelectric and pyroelectric performance. BNBT6/P(VDF-TrFE) 0-3 composites with BNBT6 volume fraction Phi ranging from 0.05 to 0.3 were prepared using solvent casting to disperse the ceramic powder in the copolymer matrix followed by hot-pressing. The pyroelectric coefficient of the composites was measured as a function of Phi under different A.C. poling conditions. As both the BNBT6 inclusion and P(VDF-TrFE) matrix can be poled under similar conditions, the composites can be poled effectively after subjected to several cycles of sinusoidal electric field. The BNBT6 0-3 composites (poled with a.c. source) were found to have better pyroelectric properties than that of lead zirconate titante PZT / P(VDF-TrFE) 0-3 composites (poled with d.c. source).","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122947697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387819
W. Borland
The integration of embedded DuPont ceramic capacitors and HiK polyimide based planar capacitor materials in IC packages has been investigated by a joint program between DuPont and Georgia Institute of Technology packaging research center (PRC). Test vehicles with different types of structures were designed, fabricated and tested for individual device characterization. The test vehicles included embedded ceramic-fired-on-foil capacitors with microvia interconnects and two sequential industry standard build-up layers on each side of a BT core. Feature sizes were 12 micron lines and spaces and 50 micron diameter microvias. Other test vehicles used a core layer without build-up layers, planar capacitor layers and arrays of discrete capacitors with different size, capacitance, and interconnection designs. Each capacitor variation was electrically characterized. The electrical performance data from the test vehicles was used to perform simulations to determine the designs offering the most effective power delivery and noise decoupling for a package having 2007 ITRS die and substrate features. The embedded ceramic capacitors show a significant improvement in power system noise decoupling and charge supply to the IC in the mid-frequency range due to the low inductance design.
{"title":"Decoupling of High Performance Semiconductors Using Embedded Capacitor Technology","authors":"W. Borland","doi":"10.1109/ISAF.2006.4387819","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387819","url":null,"abstract":"The integration of embedded DuPont ceramic capacitors and HiK polyimide based planar capacitor materials in IC packages has been investigated by a joint program between DuPont and Georgia Institute of Technology packaging research center (PRC). Test vehicles with different types of structures were designed, fabricated and tested for individual device characterization. The test vehicles included embedded ceramic-fired-on-foil capacitors with microvia interconnects and two sequential industry standard build-up layers on each side of a BT core. Feature sizes were 12 micron lines and spaces and 50 micron diameter microvias. Other test vehicles used a core layer without build-up layers, planar capacitor layers and arrays of discrete capacitors with different size, capacitance, and interconnection designs. Each capacitor variation was electrically characterized. The electrical performance data from the test vehicles was used to perform simulations to determine the designs offering the most effective power delivery and noise decoupling for a package having 2007 ITRS die and substrate features. The embedded ceramic capacitors show a significant improvement in power system noise decoupling and charge supply to the IC in the mid-frequency range due to the low inductance design.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128074623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387837
B. Trinh, S. Horita
We fabricated a new ferroelectric gate field-effect transistor memory (F-FET) with an intermediate electrode inserted between the ferroelectric capacitor (Cf) and the metal-oxide-semiconductor field-effect transistor (MOSFET) for writing data. The structure was a RuO2 top electrode/polycrystalline ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT)/(Pt/RuO2) intermediate electrode/SiO2/Si substrate. The basic operation of the new memory was confirmed by a discrete circuit that the Cf was connected serially with the MOSFET. For data writing, two positive or negative square pulses applied between the top electrode and the intermediate electrode induced the positive (Pr+) and the negative (Pr-) remanent polarizations, respectively, for coding memory states. For data reading, an unipolar square pulse train was applied between the top electrode and the source of the MOSFET, and the drain of the MOSFET was biased by a DC voltage. When the memory state corresponded to the Pr+ or the P-, the drain current (ID) was small or large, respectively. In this study, we used a polycrystalline PZT film to deal with the difficult problems of an epitaxial PZT film such as complicated techniques and high cost of products for commercialization goal.
{"title":"Fabrication of Polycrystalline Ferroelectric Gate FET Memory with an Intermediate Electrode","authors":"B. Trinh, S. Horita","doi":"10.1109/ISAF.2006.4387837","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387837","url":null,"abstract":"We fabricated a new ferroelectric gate field-effect transistor memory (F-FET) with an intermediate electrode inserted between the ferroelectric capacitor (Cf) and the metal-oxide-semiconductor field-effect transistor (MOSFET) for writing data. The structure was a RuO2 top electrode/polycrystalline ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT)/(Pt/RuO2) intermediate electrode/SiO2/Si substrate. The basic operation of the new memory was confirmed by a discrete circuit that the Cf was connected serially with the MOSFET. For data writing, two positive or negative square pulses applied between the top electrode and the intermediate electrode induced the positive (Pr+) and the negative (Pr-) remanent polarizations, respectively, for coding memory states. For data reading, an unipolar square pulse train was applied between the top electrode and the source of the MOSFET, and the drain of the MOSFET was biased by a DC voltage. When the memory state corresponded to the Pr+ or the P-, the drain current (ID) was small or large, respectively. In this study, we used a polycrystalline PZT film to deal with the difficult problems of an epitaxial PZT film such as complicated techniques and high cost of products for commercialization goal.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133181965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387906
Jang-Yong Kim, A. Grishin
AgTa0.5Nb0.5O3 (ATN) 400 nm thick films have been sintered by pulsed laser deposition technique on LaAIO3 (001), sapphire (Al2O3-011_2, r-cut) single crystal substrates and Corning 7059 glass. Photolithography and metal lift-off technique were used to fabricate tunable coplanar waveguide interdigital capacitors (CPWIDCs). On-wafer test of varactors was performed with microwave network analyzer and G-S-G microwave probe. ATN/LaAIO3 capacitors demonstrated the highest tunability (~5.8%@20GHz), ATN/Glass showed the best flat dispersion (-3.9%) and ATN/ AI2O3 showed the lowest loss tangent (~0.06@20GHz) in the microwave range from 1 to 40 GHz.
{"title":"Microwave Properties of AgTa0.5Nb0.5O3 Thin Film Varactors on Various Substrates","authors":"Jang-Yong Kim, A. Grishin","doi":"10.1109/ISAF.2006.4387906","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387906","url":null,"abstract":"AgTa<sub>0.5</sub>Nb<sub>0.5</sub>O<sub>3</sub> (ATN) 400 nm thick films have been sintered by pulsed laser deposition technique on LaAIO<sub>3</sub> (001), sapphire (Al<sub>2</sub>O<sub>3</sub>-011_2, r-cut) single crystal substrates and Corning 7059 glass. Photolithography and metal lift-off technique were used to fabricate tunable coplanar waveguide interdigital capacitors (CPWIDCs). On-wafer test of varactors was performed with microwave network analyzer and G-S-G microwave probe. ATN/LaAIO<sub>3</sub> capacitors demonstrated the highest tunability (~5.8%@20GHz), ATN/Glass showed the best flat dispersion (-3.9%) and ATN/ AI<sub>2</sub>O<sub>3</sub> showed the lowest loss tangent (~0.06@20GHz) in the microwave range from 1 to 40 GHz.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133895294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387848
C. Chao, T. Lam, K. Kwok, H. Chan
Representing a new approach to ultrasound generation and detection, study on piezoelectric micromachined ultrasonic transducers (pMUTs) has been a growing research area in recent years. Intensive research work has been directed on the deposition of lead zirconate titanate (PZT) films on silicon substrates for their excellent piezoelectric coefficients and electromechanical coupling coefficients. However, the high processing temperature required for PZT crystallization results in a low device yield and also makes it difficult to integrate with control circuits. In this paper, a fabrication technology of pMUTs based on piezoelectric P(VDF-TrFE) 70/30 copolymer films has been adopted, with the maximum processing temperature not exceeding 140degC allowing for post-IC compatibility. The entire processing procedures are simple and low cost, as compared with those of capacitive micromachined ultrasonic transducers (cMUTs) and ceramic-based pMUTs. The applications of the fabricated pMUTs as airborne ultrasonic transducers and transducer arrays have been demonstrated. Reasonably good device performances and high device yield have been achieved.
{"title":"Piezoelectric Micromachined Ultrasonic Transducers Based on P(VDF-TrFE) Copolymer Thin Films","authors":"C. Chao, T. Lam, K. Kwok, H. Chan","doi":"10.1109/ISAF.2006.4387848","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387848","url":null,"abstract":"Representing a new approach to ultrasound generation and detection, study on piezoelectric micromachined ultrasonic transducers (pMUTs) has been a growing research area in recent years. Intensive research work has been directed on the deposition of lead zirconate titanate (PZT) films on silicon substrates for their excellent piezoelectric coefficients and electromechanical coupling coefficients. However, the high processing temperature required for PZT crystallization results in a low device yield and also makes it difficult to integrate with control circuits. In this paper, a fabrication technology of pMUTs based on piezoelectric P(VDF-TrFE) 70/30 copolymer films has been adopted, with the maximum processing temperature not exceeding 140degC allowing for post-IC compatibility. The entire processing procedures are simple and low cost, as compared with those of capacitive micromachined ultrasonic transducers (cMUTs) and ceramic-based pMUTs. The applications of the fabricated pMUTs as airborne ultrasonic transducers and transducer arrays have been demonstrated. Reasonably good device performances and high device yield have been achieved.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115528960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387907
T. Kalkur, A. Jamil, N. Cramer
Ferroelectric capacitors made from Ba0.5Sr0.5TiO3 (BST) are applied as varactors in tunable, high frequency circuit applications. In this context, a voltage-controlled oscillator (VCO) based on Colpitts architecture has been designed and implemented using discrete RF BJTs and tunable ferroelectric capacitor. The tunable ferroelectric capacitor has been fabricated on quartz substrate with BST deposited by RF magnetron sputtering and platinum electrodes. At 1 MHz, the ferroelectric capacitor shows a tunability of about 30% for applied DC bias voltage of plusmn5 V and quality factor 'Q' of 160. The fabricated VCO on RF prototype board can be tuned from frequency 577 MHz to 602 MHz with a control voltage of plusmn3 V and a gain of 8.3 MHz/V and a tunability of 4%.
{"title":"Characteristics of Voltage Controlled Oscillators Implemented With Tunable Ferroelectric High-k Capacitors","authors":"T. Kalkur, A. Jamil, N. Cramer","doi":"10.1109/ISAF.2006.4387907","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387907","url":null,"abstract":"Ferroelectric capacitors made from Ba0.5Sr0.5TiO3 (BST) are applied as varactors in tunable, high frequency circuit applications. In this context, a voltage-controlled oscillator (VCO) based on Colpitts architecture has been designed and implemented using discrete RF BJTs and tunable ferroelectric capacitor. The tunable ferroelectric capacitor has been fabricated on quartz substrate with BST deposited by RF magnetron sputtering and platinum electrodes. At 1 MHz, the ferroelectric capacitor shows a tunability of about 30% for applied DC bias voltage of plusmn5 V and quality factor 'Q' of 160. The fabricated VCO on RF prototype board can be tuned from frequency 577 MHz to 602 MHz with a control voltage of plusmn3 V and a gain of 8.3 MHz/V and a tunability of 4%.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116091034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387830
Jingyan He, T. Comyn, T. Skidmore, S. J. Milne, A. Bell
Grain-oriented ceramics, in which the grains are aligned around a preferred crystallographic axis, are of interest for increasing the figure of merit of piezoelectric ceramics. Templated grain growth (TGG), in which a fine matrix is recrystallised upon oriented seed crystals, is one of the more successful techniques for preparing ceramics with such crystallographic texture. Seeds are usually required to exhibit shape anisotropy in a defined orientation with an appropriate crystallographic template plane. In this study, Bi4Ti3O12 (BiT) seeds were produced via molten-salt synthesis. The effect of temperature and dwelling time on the morphology and structure of Bi4Ti3O12 powders was studied, in order to identify the optimum conditions for seed preparation. The chosen Bi4Ti3O12 seeds were then added to PbTiO3-based matrices (Bi0.5Fe0.5Pb0.47La0.03Ti0.5O3+x) to produce Bi4Ti3O12 oriented BFPT ceramics by tape casting. The microstructure and the calculated orientation factors of the textured ceramics are reported.
{"title":"Molten-Salt Synthesis of Bismuth Titanate and Fabrication of PbTiO3-based Textured Ceramics","authors":"Jingyan He, T. Comyn, T. Skidmore, S. J. Milne, A. Bell","doi":"10.1109/ISAF.2006.4387830","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387830","url":null,"abstract":"Grain-oriented ceramics, in which the grains are aligned around a preferred crystallographic axis, are of interest for increasing the figure of merit of piezoelectric ceramics. Templated grain growth (TGG), in which a fine matrix is recrystallised upon oriented seed crystals, is one of the more successful techniques for preparing ceramics with such crystallographic texture. Seeds are usually required to exhibit shape anisotropy in a defined orientation with an appropriate crystallographic template plane. In this study, Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> (BiT) seeds were produced via molten-salt synthesis. The effect of temperature and dwelling time on the morphology and structure of Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> powders was studied, in order to identify the optimum conditions for seed preparation. The chosen Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> seeds were then added to PbTiO<sub>3</sub>-based matrices (Bi<sub>0.5</sub>Fe<sub>0.5</sub>Pb<sub>0.47</sub>La<sub>0.03</sub>Ti<sub>0.5</sub>O<sub>3+x</sub>) to produce Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> oriented BFPT ceramics by tape casting. The microstructure and the calculated orientation factors of the textured ceramics are reported.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129781561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387882
M. Guennou, C. Augier, H. Dammak, M. Thi, P. Gaucher
We studied the influence of Mn doping on electromechanical properties of PZN-xPT with x = 7% and 9%. Single crystals oriented along the [111], [011] and [001] directions were poled by a "field cooling" process with an applied electric field of 1 kV/cm. It is shown that Mn doping has a significant influence on the single domain crystals in both cases. It modifies the phase symmetry of single domain PZN-7PT from orthorhombic to rhombohedral. It reduces permittivity perpendicular to polarization direction of single domain PZN-9PT by about 40%. This change in the properties of the bulk material is the main cause for the decrease of permittivity observed in [001] poled PZN-9PT crystals. Further effects of doping on the properties of [001] domain engineered crystals are a decrease of the piezoelectric coefficient, a hardening of the material and an increase of the mechanical quality factor.
{"title":"Role of Mn Doping on the Electromechanical Properties of [001] Domain Engineered Single crystals","authors":"M. Guennou, C. Augier, H. Dammak, M. Thi, P. Gaucher","doi":"10.1109/ISAF.2006.4387882","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387882","url":null,"abstract":"We studied the influence of Mn doping on electromechanical properties of PZN-xPT with x = 7% and 9%. Single crystals oriented along the [111], [011] and [001] directions were poled by a \"field cooling\" process with an applied electric field of 1 kV/cm. It is shown that Mn doping has a significant influence on the single domain crystals in both cases. It modifies the phase symmetry of single domain PZN-7PT from orthorhombic to rhombohedral. It reduces permittivity perpendicular to polarization direction of single domain PZN-9PT by about 40%. This change in the properties of the bulk material is the main cause for the decrease of permittivity observed in [001] poled PZN-9PT crystals. Further effects of doping on the properties of [001] domain engineered crystals are a decrease of the piezoelectric coefficient, a hardening of the material and an increase of the mechanical quality factor.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129288070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387846
M. B. Assouar, B. Vincent, H. Moubchir, O. Elmazria, A. Khelif, V. Laude
We report here, the study of domain inversion in lithium niobate (z-cut) by electron beam irradiation without any static bias associated to wet etching, in view of the fabrication of phononic crystals. The inverted domains are revealed by HF-etching taking advantage of the large difference in etching rate between z+ and z-faces. A pertinent choice of irradiation conditions such as accelerating voltage, probe current and injected dose, (parameters of interest for the geometry and size of the obtained domains), was determined and optimized. Two dimensional structures at the micrometer scale were then realized on z-cut LiNbO3. We demonstrate the achievement of 8 mum diameter hexagons, with a very large depth close to 30 mum, which depends on the etching time. The obtained structures were characterized before etching by optical microscopy to visualize the inverted domains, and after etching by field emission scanning electron microscopy. These characterisations pointed out the high occupancy rate of obtained structures. Numerical simulations of the realized phononic structure band gap show a frequency band gap around 200 MHz.
{"title":"Domains Inversion in LiNbO3 Using Electron Beam Irradiation for Phononic Crystals","authors":"M. B. Assouar, B. Vincent, H. Moubchir, O. Elmazria, A. Khelif, V. Laude","doi":"10.1109/ISAF.2006.4387846","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387846","url":null,"abstract":"We report here, the study of domain inversion in lithium niobate (z-cut) by electron beam irradiation without any static bias associated to wet etching, in view of the fabrication of phononic crystals. The inverted domains are revealed by HF-etching taking advantage of the large difference in etching rate between z+ and z-faces. A pertinent choice of irradiation conditions such as accelerating voltage, probe current and injected dose, (parameters of interest for the geometry and size of the obtained domains), was determined and optimized. Two dimensional structures at the micrometer scale were then realized on z-cut LiNbO3. We demonstrate the achievement of 8 mum diameter hexagons, with a very large depth close to 30 mum, which depends on the etching time. The obtained structures were characterized before etching by optical microscopy to visualize the inverted domains, and after etching by field emission scanning electron microscopy. These characterisations pointed out the high occupancy rate of obtained structures. Numerical simulations of the realized phononic structure band gap show a frequency band gap around 200 MHz.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127854638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-07-01DOI: 10.1109/ISAF.2006.4387823
E. Gorzkowski, M. Pan, B. Bender, C. Wu
Barium strontium titanate has been targeted as one potential ferroelectric glass-ceramic for high energy density dielectric materials. Previous testing has shown that the dielectric constant of these materials was as high as 1000 and dielectric breakdown strength up to 800 kV/cm. This did not, however, result in exceptional energy density (~ 0.90 J/cm3). In order to increase overall energy density refining agents can be added to the melt, but the nucleation and growth of the ceramic particles can also play a role. Therefore, in this study the crystallization kinetics were observed to more fully understand how the barium strontium titanate (BST) phase forms so that the optimal energy density could be achieved. It was found that the activation energy was 400 -430 kJ/mol, while the average Avrami parameter was 2.2 -2.5 for BST 70/30 with various additives. The activation energy is close to the disassociation of the Si-O bonds, while crystallization most likely occurs in the bulk with the mechanism of growth being interface controlled.
{"title":"Crystallization Kinetics of Barium Strontium Titanate Glass-Ceramics","authors":"E. Gorzkowski, M. Pan, B. Bender, C. Wu","doi":"10.1109/ISAF.2006.4387823","DOIUrl":"https://doi.org/10.1109/ISAF.2006.4387823","url":null,"abstract":"Barium strontium titanate has been targeted as one potential ferroelectric glass-ceramic for high energy density dielectric materials. Previous testing has shown that the dielectric constant of these materials was as high as 1000 and dielectric breakdown strength up to 800 kV/cm. This did not, however, result in exceptional energy density (~ 0.90 J/cm3). In order to increase overall energy density refining agents can be added to the melt, but the nucleation and growth of the ceramic particles can also play a role. Therefore, in this study the crystallization kinetics were observed to more fully understand how the barium strontium titanate (BST) phase forms so that the optimal energy density could be achieved. It was found that the activation energy was 400 -430 kJ/mol, while the average Avrami parameter was 2.2 -2.5 for BST 70/30 with various additives. The activation energy is close to the disassociation of the Si-O bonds, while crystallization most likely occurs in the bulk with the mechanism of growth being interface controlled.","PeriodicalId":441219,"journal":{"name":"2006 15th ieee international symposium on the applications of ferroelectrics","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128772205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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