scholarly journals Piezoelectric Ultrasonic Micromotor

2021 ◽  
Vol 4 (1) ◽  
pp. 24
Author(s):  
Giorgio Casiraghi ◽  
Daniele Caltabiano ◽  
Andrea Picco ◽  
Stefano Mariani
Keyword(s):  
Sol Gel ◽  
Integrated Approach ◽  
Dielectric Constants ◽  
Electric Signal ◽  
Concept Design ◽  
Tooth Structure ◽  
Multiphysics Simulations ◽  
Gear Trains ◽  
High Torque ◽  
Piezoelectric Films

Ultrasonic motors are characterized by low speed and high-torque operation, without the need for gear trains. They can be compact and lightweight, and they can also work in the absence of applied loads, due to the frictional coupling between the rotor and the stator induced by the traveling wave. In this work, we discuss a concept design based on thin piezoelectric films, sol-gel directly deposited onto a silicon substrate to provide high-torque motors compatible with wafer integration technologies. Due to the large dielectric constants and the enhanced breakdown strengths of thin piezoelectric films, such ultrasonic micromotors can lead to meaningful improvements over electrostatic ones in terms of energy density. As far as the fabrication of the micromotor at the mm-scale is concerned, an integrated approach is proposed with significant improvements regarding: the comb-tooth structure, to maximize/optimize the motor torque; a back and front etch lithographic process; and the design of the electrodes, which provide the electric signal at the central anchor of the stator, taking advantage of low-temperature soldering. The proposed design has been assessed through multiphysics simulations, carried out to evaluate the resonant behavior of the stator and the motor performance in terms of angular velocity, torque, and output power, and it is shown to lead to promising results.

Electron microscopy studies of PZT ferroelectric film capacitor structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1364-1365
Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  
Keyword(s):  
Electric Fields ◽  
Sol Gel ◽  
Ferroelectric Material ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Lead Zirconium Titanate ◽  
Si Substrate ◽  
Film Capacitor ◽  
Pzt Films ◽  
High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

scholarly journals Synthesis and characterization of Mg–Zn ferrite based flexible microwave composites and its application as SNG metamaterial

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Md Atiqur Rahman ◽  
Mohammad Tariqul Islam ◽  
Mandeep Singh Jit Singh ◽  
Md Samsuzzaman ◽  
Muhammad E. H. Chowdhury
Keyword(s):  
Low Cost ◽  
Sol Gel ◽  
Microwave Frequency ◽  
Dielectric Substrate ◽  
Dielectric Constants ◽  
Potential Candidate ◽  
Flexible Composites ◽  
Average Grain Size ◽  
Zn Ferrite ◽  
High Flexibility

AbstractIn this article, we propose SNG (single negative) metamaterial fabricated on Mg–Zn ferrite-based flexible microwave composites. Firstly, the flexible composites are synthesized by the sol-gel method having four different molecular compositions of MgxZn(1−x)Fe2O4, which are denoted as Mg20, Mg40, Mg60, and Mg80. The structural, morphological, and microwave properties of the synthesized flexible composites are analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and conventional dielectric assessment kit (DAK) to justify their possible application as dielectric substrate at microwave frequency regime. Thus the average grain size is found from 20 to 24 nm, and the dielectric constants are 6.01, 5.10, 4.19, and 3.28, as well as loss tangents, are 0.002, 0.004, 0.006, and 0.008 for the prepared Mg–Zn ferrites, i.e., Mg20, Mg40, Mg60, and Mg80 respectively. Besides, the prepared low-cost Mg–Zn ferrite composites exhibit high flexibility and lightweight, which makes them a potential candidate as a metamaterial substrate. Furthermore, a single negative (SNG) metamaterial unit cell is fabricated on the prepared, flexible microwave composites, and their essential electromagnetic behaviors are observed. Very good effective medium ratios (EMR) vales are obtained from 14.65 to 18.47, which ensure the compactness of the fabricated prototypes with a physical dimension of 8 × 6.5 mm2. Also, the proposed materials have shown better performances comparing with conventional FR4 and RO4533 materials, and they have covered S-, C-, X-, Ku-, and K-band of microwave frequency region. Thus, the prepared, flexible SNG metamaterials on MgxZn(1−x)Fe2O4 composites are suitable for microwave and flexible technologies.

ChemInform Abstract: Sol-Gel-Derived Mesoporous Silica Films with Low Dielectric Constants.

ChemInform ◽  
2001 ◽  
Vol 32 (10) ◽  
pp. no-no
Author(s):  
Seana Seraji ◽  
Yun Wu ◽  
Michael Forbess ◽  
Steven J. Limmer ◽  
Tammy Chou ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Silica Films ◽  
Low Dielectric

Microstructure and Dielectric Properties of LixTixNi1-2xO Thin Films

2008 ◽  
Vol 368-372 ◽  
pp. 1817-1819
Author(s):  
Cui Hua Zhao ◽  
Bo Ping Zhang ◽  
Yong Liu ◽  
Song Jie Li
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Spin Coating ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Co Doping ◽  
Grain Sizes ◽  
Uniform Microstructure ◽  
Coating Method ◽  
High Dielectric

LixTixNi1-2xO (x =0, 10 and 20 at. %) thin films with 200 nm in thickness were deposited on Pt/Ti/SiO2/Si (100) by a sol-gel spin-coating method. All samples have a uniform microstructure. The grain sizes grew from 100 nm to 300 nm by co-doping Li and Ti. The LiTiNiO thin films consist of NiO, NiTiO3 and Li2NiO2, while the Li-free thin films consist of NiO, NiTiO3 and NiTi0.99O3. The dielectric properties of the LiTiNiO thin films improved obviously by co-doping Li and Ti, but excess Li increases the amount of Li2NiO2 phase and decreases the dielectric properties. The dielectric constants at 100 Hz for the Li0.1Ti0.1Ni0.8O and Li0.2Ti0.2Ni0.6O thin films are 506 and 388 respectively. Appropriate co-doping contents of Li and Ti are important to obtain a high dielectric property.

New Carbon-bridged Hybrid Polymers for Low-k Materials

2005 ◽  
Vol 863 ◽  
Author(s):  
Bum-Gyu Choi ◽  
Byung Ro Kim ◽  
Myung-Sun Moon ◽  
Jung-Won Kang ◽  
Min-Jin Ko
Keyword(s):  
Mechanical Properties ◽  
Hybrid Materials ◽  
Chemical Mechanical Planarization ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Metal Line ◽  
Inorganic Hybrid ◽  
Low Dielectric ◽  
Continuous Stiffness Measurement ◽  
Low K

AbstractReducing interline capacitance and line resistance is required to minimize RC delays, reduce power consumption and crosstalk below 100nm node technology. For this purpose, various inorganic- and organic polymers have been tested to reduce dielectric constants in parallel with the use of copper as metal line. Lowering the dielectric constants, in particular, causes the detrimental effect on mechanical properties, and then leads to film damage and/or delamination during chemical-mechanical planarization CMP) or repeated thermal cure cycles. To overcome this issue, new carbon-bridged hybrid materials synthesized by organometallic silane precursors and sol-gel reaction are proposed.In this work, we have developed new organic-inorganic hybrid low-k dielectrics with linear or cyclic carbon bridged structures. The differently bridged carbon structures were formed by a controlled reaction. 1H NMR, 29Si NMR analysis and GC/MSD analysis were conducted for the structural characterization of new hybrid low-k dielectric. The mechanical and dielectric properties of these hybrid materials were characterized by using nanoindentation with continuous stiffness measurement and Al dot MIS techniques. The results indicated that these organic-inorganic hybrid materials were very promising polymers for low-k dielectrics that had low dielectric constants with high thermal and mechanical properties. It has been also demonstrated that electrical and mechanical properties of the hybrid films could be tailored by copolymerization with PMSSQ and through the introduction of porogen.

SPECTROSCOPIC ELLIPSOMETRY INVESTIGATION ON OPTICAL PROPERTIES OF Fe:SNO2 THIN FILMS: EFFECTS OF IRON CONCENTRATION

2020 ◽  
pp. 2050044
Author(s):  
SAHAR MORADI ◽  
HASSAN SEDGHI
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Sol Gel ◽  
Iron Concentration ◽  
Dielectric Constants ◽  
Bandgap Energy ◽  
Dispersion Parameters ◽  
Glass Substrates ◽  
Coating Method

Nanostructured Fe:SnO2 thin films were deposited on glass substrates through sol–gel spin coating method. Films were synthesized with different iron quantities including 0%, 4%, 8% and 12% (wt.%). The effects of Fe concentration on optical properties of films were investigated by spectroscopic ellipsometry (SE) technique. SE measured ([Formula: see text]) parameters for films in the wavelength range between 300[Formula: see text]nm to 800[Formula: see text]nm. Optical properties including the refractive index, extinction coefficient, transmittance, dielectric constants and optical conductivity were determined by fitting the SE measured ([Formula: see text]) parameters and data obtained from the optical model-based analysis. Results showed that the transmittance values increase by increment of Fe concentration from 0% to 12%. The bandgap energy ([Formula: see text] of prepared thin films was also calculated. [Formula: see text] values were between 3.44 and 3.58[Formula: see text]eV. Dispersion parameters including the high frequency dielectric constant ([Formula: see text] and the ratio of free carrier concentration to effective mass (N/m[Formula: see text] were then obtained for the prepared films.

scholarly journals Nanocrystalline Antiferromagnetic High-κ Dielectric Sr2NiMO6 (M = Te, W) with Double Perovskite Structure Type

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3996
Author(s):  
Jelena Bijelić ◽  
Dalibor Tatar ◽  
Sugato Hajra ◽  
Manisha Sahu ◽  
Sang Jae Kim ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Sol Gel ◽  
Double Perovskite ◽  
Structure Type ◽  
Nyquist Plot ◽  
Dielectric Constants ◽  
Nanocrystalline Powders ◽  
Double Perovskites ◽  
Magnetic Studies ◽  
Magnetic Ground State

Double perovskites have been extensively studied in materials chemistry due to their excellent properties and novel features attributed to the coexistence of ferro/ferri/antiferro-magnetic ground state and semiconductor band gap within the same material. Double perovskites with Sr2NiMO6 (M = Te, W) structure type have been synthesized using simple, non-toxic and costless aqueous citrate sol-gel route. The reaction yielded phase-pure nanocrystalline powders of two compounds: Sr2NiWO6 (SNWO) and Sr2NiTeO6 (SNTO). According to the Rietveld refinement of powder X-ray diffraction data at room temperature, Sr2NiWO6 is tetragonal (I4/m) and Sr2NiTeO6 is monoclinic (C12/m1), with average crystallite sizes of 49 and 77 nm, respectively. Structural studies have been additionally performed by Raman spectroscopy revealing optical phonons typical for vibrations of Te6+/W6+O6 octahedra. Both SNTO and SNWO possess high values of dielectric constants (341 and 308, respectively) with low dielectric loss (0.06 for SNWO) at a frequency of 1 kHz. These values decrease exponentially with the increase of frequency to 1000 kHz, with the dielectric constant being around 260 for both compounds and dielectric loss being 0.01 for SNWO and 0.04 for SNTO. The Nyquist plot for both samples confirms the non-Debye type of relaxation behavior and the dominance of shorter-range movement of charge carriers. Magnetic studies of both compounds revealed antiferromagnetic behavior, with Néel temperature (TN) being 57 K for SNWO and 35 K for SNTO.

The Effect of Hydrolysis Conditions on the Characteristics of PbTiO3 Gels and Thin Films

1986 ◽  
Vol 72 ◽  
Author(s):  
K. D. Budd ◽  
S. K. Dey ◽  
D. A. Payne
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Electronic Ceramics ◽  
Base Catalysts ◽  
Acid And Base ◽  
Crystalline Films ◽  
Continuous Crack ◽  
Free Films ◽  
Hydrolysis Conditions

AbstractSol-gel processing represents a promising method of fabrication for thin films of electronic ceramics which are useful in a number of packaging and device applications. In this study, the influence of acid and base catalysts on the structure of PbTiO3 gels and films (0.1-1.0μm) was investigated, for the purpose of inducing and identifying gel structures which were the most suitable as precursors for thin dielectric layers. Continuous, crack-free films, with dielectric strengths in excess of 106 V/cm were developed. Basic solutions gelled rapidly, phase separated, and were probably more crosslinked than acidic gels. Acidic gels seemed more capable of polymeric rearrangement during drying, yielding denser amorphous structures with microcrystalline regions. High-field dielectric constants (1 MV/m ac) in the range K=30–40, and K=160–170, were determined for amorphous and crystalline films, respectively.

Dielectric Properties of Sol - Gel Silica Glasses

1986 ◽  
Vol 72 ◽  
Author(s):  
G. V. Chandrashekhar ◽  
M. W. Shafer
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Elemental Carbon ◽  
Sol Gel ◽  
Fused Silica ◽  
Dielectric Constants ◽  
Low Dielectric Constant ◽  
Silica Glasses ◽  
Low Dielectric ◽  
Gel Technique

AbstractDielectric properties have been measured for a series of porous and fully densified silica glasses, prepared by the sol-gel technique starting from Si-methoxide or Si-fume. The results for the partially densified glasses do not show any preferred orientation for porosity. When fully densified (˜2.25 gms/cc) without any prior treatment of the gels, they have dielectric constants of ≥ 6.5 and loss factors of 0.002 at 1 MHz, compared to values of 3.8 and <0.001 for commercial fused silica. There is no corresponding anomaly in the d.c. resistivity. Elemental carbon present to the extent of 400–500 ppm is likely to be the main cause for this enhanced dielectric constant. Extensive cleaning of the gels prior to densification to remove this carbon were not completely successful pointing to the difficulty in preparing high purity, low dielectric constant glasses via the organic sol-gel route at least in the bulk form.

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