scholarly journals Fabrication and Characterization of Metalferroelectric-GAN Structures

2000 ◽  
Vol 5 (S1) ◽  
pp. 598-604
Author(s):  
W.P. Li ◽  
R. Zhang ◽  
J. Yin ◽  
X.H. Liu ◽  
Y.G. Zhou ◽  
...  
Keyword(s):  
High Frequency ◽  
High Dielectric Constant ◽  
Oxide Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Active Layers ◽  
Pzt Films ◽  
High Dielectric ◽  
Mos Structures

GaN-based metal-ferroelectric-semiconductor (MFS) structure has been fabricated by using ferroelectric Pb(Zr0.53Ti0.47)O3 (PZT) instead of conventional oxides as gate insulators. The GaN and PZT films in the MFS structures have been characterized by various methods such as photoluminescence (PL), wide-angle X-ray diffraction (XRD) and high-resolution X-ray diffraction (HRXRD). The Electric properties of GaN MFS structure with different oxide thickness have been characterized by high-frequency C-V measurement. When the PZT films are as thick as 1 μm, the GaN active layers can approach inversion under the bias of 15V, which can not be observed in the traditional GaN MOS structures. When the PZT films are about 100 nm, the MFS structures can approach inversion just under 5V. All the marked improvements of C-V behaviors in GaN MFS structures are mainly attributed to the high dielectric constant and large polarization of the ferroelectric gate oxide.

Fabrication and Characterization of Metal-Ferroelectric-Gan Structures

1999 ◽  
Vol 595 ◽  
Author(s):  
W.P. Li ◽  
R. Zhang ◽  
J. Yin ◽  
X.H. Liu ◽  
Y.G. Zhou ◽  
...  
Keyword(s):  
High Frequency ◽  
High Dielectric Constant ◽  
Oxide Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Active Layers ◽  
Pzt Films ◽  
High Dielectric ◽  
Mos Structures

AbstractGaN-based metal-ferroelectric-semiconductor (MFS) structure has been fabricated by using ferroelectric Pb(Zr0.53Ti0.47)O3 (PZT) instead of conventional oxides as gate insulators. The GaN and PZT films in the MFS structures have been characterized by various methods such as photoluminescence (PL), wide-angle X-ray diffraction (XRD) and high-resolution X-ray diffraction (HRXRD). The Electric properties of GaN MFS structure with different oxide thickness have been characterized by high-frequency C-V measurement. When the PZT films are as thick as 1 µm, the GaN active layers can approach inversion under the bias of 15V, which can not be observed in the traditional GaN MOS structures. When the PZT films are about 100 nm, the MFS structures can approach inversion just under 5V. All the marked improvements of C-V behaviors in GaN MFS structures are mainly attributed to the high dielectric constant and large polarization of the ferroelectric gate oxide.

The Synthesis and Characterization of SrTiO3 Film Fabricated by Micro Arcoxidation

2011 ◽  
Vol 311-313 ◽  
pp. 1262-1266 ◽  
Author(s):  
Hui Yong Guo ◽  
Wen Bo Huang ◽  
Wen Fang Li ◽  
Guo Ge Zhang ◽  
En Fu Wang
Keyword(s):  
Surface Morphology ◽  
High Dielectric Constant ◽  
Electrolyte Concentration ◽  
Pure Titanium ◽  
Xrd Analysis ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Dielectric

Pure titanium plates as anode and mixture of solutions containing 0.2M Sr(OH)2and 0.2M NaOH as electrolyte, titanium plates were microarc-oxidated for 10 minutes. X-Ray Diffraction (XRD) analysis indicated that SrTiO3film was successfully deposited. The MAO film is composed mainly of tetragonal SrTiO3phases and found to possess high dielectric constant of 371.0 at the frequency of 1 kHz. Scanning Electron Microscopy (SEM) and portable roughness tester were used to characterize the surface morphology and roughness values(Ra), The influences of electrolyte concentration, current density and frequency on the surface morphology of SrTiO3film were investigated in detail . several rules were drawn from the results. A kinetics expression was established for the growth of film thickness and agreed well with the experimental results.

Structural and dielectric properties of Ca1-x MgxCu3Ti4O12 thin films

2003 ◽  
Vol 785 ◽  
Author(s):  
L. A. Bermúdez ◽  
R. P. Guzman ◽  
M.S. Tomar ◽  
R.E. Melgarejo
Keyword(s):  
Thin Films ◽  
Single Phase ◽  
High Dielectric Constant ◽  
Film Material ◽  
X Ray Diffraction ◽  
Detailed Characterization ◽  
Chemical Route ◽  
X Ray ◽  
High Dielectric

ABSTRACTCa1-xMgxCu3Ti4O12 material has been synthesized by chemical route for different compositions and thin films have been deposited by spin coating. X-ray diffraction and Raman spectroscopy were used for detailed characterization of this material for both powder and thin films. X-ray diffraction shows single phase film material for different compositions x < 0.80. The initial measurements on dielectric response indicates high dielectric constant > 10, 000 for the composition x = 0.1.

The Synthesis and Characterization of Ba0.5Sr0.5TiO3 Film Fabricated by Micro Arc Oxidation

2012 ◽  
Vol 151 ◽  
pp. 266-270
Author(s):  
Ming Wang ◽  
Hui Yong Guo ◽  
Wen Bo Huang ◽  
Wen Fang Li
Keyword(s):  
Surface Morphology ◽  
High Dielectric Constant ◽  
Energy Dispersive Spectrometer ◽  
X Ray Diffraction ◽  
Titanium Plate ◽  
X Ray ◽  
Low Dielectric ◽  
Micro Arc Oxidation ◽  
High Dielectric

Ba0.5Sr0.5TiO3film was successfully fabricated by micro arc oxidation of titanium plate in aqueous solution containing Sr(OH)2and Ba(OH)2for 25 minutes. X-ray diffraction , energy dispersive spectrometer and scanning electron microscopy were used to characterize the crystalline structure, elements composition and surface morphology and HP4284 capacitance prober was used to analyze the dielectric properties of the film. The micro arc oxidation film is mainly composed of tetragonal Ba0.5Sr0.5TiO3 phases and possesses both high dielectric constant of 454.2 and low dielectric loss of 0.052 at the frequency of 100Hz.The surface morphology appeares smooth and homogeneous except that some holes are uniformly distributed outwardly.

scholarly journals Synthesis And Characterization of Cobalt-Zinc Spinel Ferrites For High Frequency Applications

2021 ◽  
Author(s):  
Salma Aman ◽  
Tahani I. Al-Muhimeed ◽  
Zaki Ismail Zaki ◽  
Zeinhom M. El-Bahy ◽  
Abeer A. AlObaid ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
High Frequency ◽  
Sol Gel ◽  
Secondary Phase ◽  
Spinel Ferrites ◽  
Dc Resistivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Dielectric

Abstract Spinel ferrites are attractive for high frequency applications due to their larger direct current (dc) resistivity and low dielectric loss. In the present work, Co0.6Zn0.4HoxFe2-xO4 (x = 0.00 and 0.1) spinel ferrites were prepared by sol-gel method. The X-ray diffraction pattern showed that both samples had cubic spinel structure, while in sample (x = 0.1), the secondary phase (HoFeO3) was also observed. The dc resistivity was increased with the addition of holmium ions. As the temperature increased, the dc resistivity was decreased by proving their semiconducting nature. The dielectric properties were also measured as a function of temperature and frequency. The sample which was composed by the substitution of holmium ions contained low value of dielectric loss. The magnetic properties were also experimentally measured by applying the field up to 2000 oersted. The small area covered by hysteresis loop proved that both samples possessed soft nature of magnetic materials.

scholarly journals Synthesis of Ferroelectric Perovskites Through Aqueous Solutions Techniques

1992 ◽  
Vol 271 ◽  
Author(s):  
G. Guzmàn-Martel ◽  
M. A. Aegerter ◽  
P. Barboux
Keyword(s):  
Aqueous Solutions ◽  
High Dielectric Constant ◽  
Perovskite Phase ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
X Ray ◽  
Pure Phase ◽  
High Dielectric ◽  
Hydrolysis Conditions ◽  
Hydrolysis Of

ABSTRACTThe hydrolysis of niobates in aqueous solutions has been studied as a function of pH and concentration. The process has been applied to the coprecipitation of PbNb2/3Mg1/3O3 leading to a low temperature synthesis of this ferroelectric relaxor ceramic. The effect of hydrolysis conditions such as the concentration of bases and acids used, their rate of addition, temperature and the nature of the precursor salts is described. The homogeneity of the precipitates has been characterized through infrared spectroscopy and X-ray diffraction techniques. The perovskite phase appears after heating at 350°C and is obtained as a pure phase above 750°C after one hour heat-treatment. Relaxor ceramics with high dielectric constant can be obtained by sintering above 1000°C. The process also has been successfully applied to the synthesis of other relaxor ceramic compositions such as PZN (PbNb2/3Zn1/3O3), PFN (PbNb1/2Fe1/2O3) as well as CdNb2O6 and MgNb2O6 compounds.

Growth and Characterization of PbTiO3 and Pb(Zr,Ti)O3 Thin Films by MOCVD

1994 ◽  
Vol 361 ◽  
Author(s):  
Y. Gao ◽  
W. Dong ◽  
B.A. Turtle
Keyword(s):  
Thin Films ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Depth Profiling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Pzt Films ◽  
Uniform Composition

ABSTRACTFerroelectric PbTiO3 and Pb(Zr,Ti)O3 thin films with a perovskite structure were grown on MgO and Pt/Ti/SiO2/Si by MOCV.D. The microstructure and composition of the films were characterized by x-ray diffraction, SEM, and AES. Preferred orientation of either (111) or (100)/(001) was obtained on the Pt/Ti/SiO2/Si substrates at temperatures from 600 °C to 650 °C The preferred (111) orientation was attributed to the formation of the Pt3Ti phase in the Pt layer of the substrates, whereas the (100)/(001) orientations were inferred as the growth rate effect. AES depth profiling indicated a uniform composition through the thickness of the PZT films. However, SEM showed different topography and microstructure of the PZT films deposited in different oxygen partial pressure. Electrical properties of the PZT films appear varied as a function of the oxygen partial pressure in the reactor.

Al–Ta Bilayer as an Oxidation Resistant Barrier for Electrode Structures in High Dielectric Constant Capacitors

1999 ◽  
Vol 14 (4) ◽  
pp. 1581-1588 ◽  
Author(s):  
A. Grill ◽  
C. Cabral
Keyword(s):  
Electron Spectroscopy ◽  
Oxygen Diffusion ◽  
High Dielectric Constant ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Si Substrates ◽  
Lanthanum Titanate ◽  
Oxidation Resistant ◽  
High Dielectric

Aluminum-tantalum bilayers have been investigated for their potential to serve as conductive barriers to oxygen diffusion when annealed at conditions corresponding to crystallization of perovskite dielectrics such as lead lanthanum titanate (PLT). Ta (50 nm)/Al (15 nm) structures have been deposited on Si substrates and annealed in oxygen at 650 and 700 °C for various amounts of time. The as-deposited and annealed structures have been characterized by x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), and Auger electron spectroscopy (AES) analysis and by four-point probe electrical measurements. It has been found that the Al–Ta structures can withstand complete oxidation when exposed to oxygen at 650 °C for 30 min or 700 °C for 1 min and the oxide layer formed at the surface of the structure acts as a barrier to further oxygen diffusion. When a PLT film was deposited directly on the Al–Ta structures intermixing took place. It was therefore necessary to insert a Pt layer between the Al–Ta barrier and PLT layer. In such a case the PLT showed electrical properties similar to those obtained when deposited on SiO2/Pt; however, the Al–Ta structure did interact with Pt during the perovskite formation anneal. It has been found that this interaction can be prevented by preannealing the Al–Ta, in oxygen, prior to the deposition of Pt.

Relaxor Ferroelectricity and Electrostrictive Behavior of KNN-ST Ceramics

2010 ◽  
Vol 654-656 ◽  
pp. 1978-1981
Author(s):  
Hui Qing Fan ◽  
Zhuo Li ◽  
Peng Rong Ren ◽  
Gang Cheng Jiao
Keyword(s):  
Electric Fields ◽  
High Dielectric Constant ◽  
Narrow Range ◽  
Ferroelectric Properties ◽  
Lead Magnesium Niobate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Magnesium ◽  
Diffraction Patterns ◽  
High Dielectric

The new electrostrictive ceramics have been produced from the (1-x) K0.5Na0.5NbO3-xSrTiO3 (KNN-ST, x=0.1-0.25) system by using conventional mixed-oxide methods. Sintering temperatures rise with increasing SrTiO3 content (x=0.1-0.25) and are in a very narrow range. The x-ray diffraction patterns indicate that with the increasing of SrTiO3 up to 0.25, KNN-ST ceramics with a single perovskite structure exhibit a transition from orthorhombic to cubic and no other impure phase appeared. The dielectric and relaxor ferroelectric properties of KNN-ST ceramics are investigated with the different SrTiO3 content. Also, the strain of these ceramics induced by applied electric fields have been studied. The electrostrictive response is similarly as in the classical PMN (lead magnesium niobate), but lower (order of the 10-5) than PMN (order of the 10-3). Furthermore, this system shows translucent, high dielectric constant, thus suggests possible applications in electric-optic devices, electromechanical transducer applications.

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