共查询到20条相似文献,搜索用时 31 毫秒
1.
Shih-Yuan Lin Ying-Chung Chen Chih-Ming Wang Kuo-Sheng Kao Chih-Yuan Chan 《Journal of Electronic Materials》2009,38(3):453-459
Calcium copper titanium oxide (CaCu3Ti4O12, abbreviated to CCTO) films were deposited on Pt/Ti/SiO2/Si substrates at room temperature (RT) by radiofrequency magnetron sputtering. As-deposited CCTO films were treated by rapid
thermal annealing (RTA) at various temperatures and in various atmospheres. X-ray diffraction patterns and scanning electron
microscope (SEM) images demonstrated that the crystalline structures and surface morphologies of CCTO thin films were sensitive
to the annealing temperature and ambient atmosphere. Polycrystalline CCTO films could be obtained when the annealing temperature
was 700°C in air, and the grain size increased signifi- cantly with annealing in O2. The 0.8-μm CCTO thin film that was deposited at RT for 2 h and then annealed at 700°C in O2 exhibited a high dielectric constant (ε′) of 410, a dielectric loss (tan δ) of 0.17 (at 10 kHz), and a leakage current density (J) of 1.28 × 10−5 A/cm2 (at 25 kV/cm). 相似文献
2.
Congcong Liu Fengxing Jiang Mingyu Huang Baoyang Lu Ruirui Yue Jingkun Xu 《Journal of Electronic Materials》2011,40(5):948-952
Free-standing poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT- PSS)/Ca3Co4O9 composite films have been successfully prepared by mechanically blending Ca3Co4O9 powder and PEDOT-PSS solution (Baytron P) and casting the mixed solution on polypropylene (PP) film substrates. X-ray diffraction
(XRD) and scanning electron microscopy (SEM) characterization indicated that the Ca3Co4O9 particles were in the shape of sheets and composited well together with PEDOT-PSS. Thermoelectric (TE) measurements revealed
that the Seebeck coefficient can be improved by increasing the Ca3Co4O9 content in the composite films, with the largest enhancement being 24.8% compared with a free-standing PEDOT-PSS film. However,
it is also shown that the power factor of the composite films decreases with increasing Ca3Co4O9 content, mainly due to the decline of electrical conductivity and the limited improvement of the Seebeck coefficient. 相似文献
3.
Ja-Young Jung Shin-Bok Lee Ho-Young Lee Young-Chang Joo Young-Bae Park 《Journal of Electronic Materials》2008,37(8):1111-1118
Anodic dissolution characteristics and electrochemical migration (ECM) behavior of Sn-3.0Ag-0.5Cu solder in NaCl and Na2SO4 solutions were investigated using anodic polarization tests and water drop tests (WDT). The ECM lifetime of Sn-3.0Ag-0.5Cu
solder in NaCl solution (42.4 s) was longer than that in Na2SO4 solution (34.8 s). The pitting potential of Sn-3.0Ag-0.5Cu solder in NaCl solution (135 mV, SCE) was higher than that in
Na2SO4 solution (−367 mV, SCE). The passivity film (SnO2) formed on Sn-3.0Ag-0.5Cu solder during WDTs in NaCl solution was thicker than that formed in Na2SO4 solution. Therefore, the longer ECM lifetime of Sn-3.0Ag-0.5Cu solder in NaCl solution than in Na2SO4 solution can be attributed to the higher pitting potential in the NaCl solution, which is ascribed to the formation of a
thicker passivity film (SnO2) in the former. It was confirmed that microelements such as Ag and Cu do not take part in ECM because they form chemically
stable intermetallic compounds with Sn. We believe that Sn is the only element that contributes to ECM, and dissolution of
Sn at the anode is possibly the rate-determining step of ECM of Sn-3.0Ag-0.5Cu solder. 相似文献
4.
Cheng-Hsing Hsu 《Journal of Electronic Materials》2011,40(10):2159-2165
Optical and dielectric properties and microstructures of ZnO-doped (Zr0.8Sn0.2)TiO4 thin films prepared by radiofrequency (rf)-magnetron sputtering on indium tin oxide/glass substrates at different rf powers
and substrate temperatures have been investigated. Selected-area diffraction patterns showed that the deposited films exhibited
a polycrystalline microstructure. All films exhibited the ZnO-doped (Zr0.8Sn0.2)TiO4 structure with the (111) orientation perpendicular to the substrate surface. The grain size as well as the deposition rate
of the film increased with an increase in both rf power and substrate temperature. At an annealing temperature of 700°C, the
ZnO-doped (Zr0.8Sn0.2)TiO4 film possessed a dielectric constant of 47 at 10 MHz, a dissipation factor of 0.02 at 10 MHz, a leakage current density of
7.35 × 10−9 A/cm2 at an electrical field of 1 kV/cm, average transmission in the visible range of over 70%, and an optical bandgap of 3.6 eV.
This film will allow fabrication of fully transparent semiconductor devices such as a resistive random-access memory (RRAM)
and thin-film transistors (TFTs) completely based on ZnO-doped (Zr0.8Sn0.2)TiO4 thin films. 相似文献
5.
O. M. Orlov D. R. Islamov A. G. Chernikova M. G. Kozodaev A. M. Markeev T. V. Perevalov V. A. Gritsenko G. Ya. Krasnikov 《Russian Microelectronics》2016,45(5):350-356
The mechanism responsible for the charge transport in thin ferroelectric Hf0.5Zr0.5O2 films has been studied. It is shown that in these films the transport mechanism is phonon-assisted tunneling between the traps. The optimal thickness of dielectric film for TiN/Hf0.5Zr0.5O2/Pt structures is determined. As a result of comparing the experimental current–voltage (I–V) characteristics of TiN/Hf0.5Zr0.5O2/Pt structures with the calculated ones, the thermal and optical energies of the traps are determined and the concentration of the traps is estimated. A comparison between the transport properties of ferroelectric and amorphous Hf0.5Zr0.5O2 films is carried out. It is shown that the charge transport mechanism in this dielectric does not depend on its crystalline phase. A method for decreasing leakage currents in Hf0.5Zr0.5O2 is proposed. A study of the resource of repolarization cycles for TiN/Hf0.5Zr0.5O2/TiN metal-dielectric-metal (MDM) structures fully grown by atomic layer deposition (ALD) has been carried out. 相似文献
6.
Ping Wei Wen-Yu Zhao Chun-Lei Dong Bing Ma Qing-Jie Zhang 《Journal of Electronic Materials》2010,39(9):1803-1808
Filled skutterudite thermoelectric (TE) materials have been extensively studied to search for better TE materials in the past
decade. However, there is no detailed investigation about the thermal stability of filled skutterudite TE materials. The evolution
of microstructure and TE properties of nanostructured skutterudite materials fabricated with Ba0.3In0.2Co3.95Ni0.05Sb12/SiO2 core–shell composite particles with 3 nm thickness shell was investigated during periodic thermal cycling from room temperature
to 723 K in this work. Scanning electronic microscopy and electron probe microscopy analysis were used to investigate the
microstructure and chemical composition of the nanostructured skutterudite materials. TE properties of the nanostructured
skutterudite materials were measured after every 200 cycles of quenching in the temperature range from 300 K to 800 K. The
results show that the microstructure and composition of Ba0.3In0.2Co3.95Ni0.05Sb12/SiO2 nanostructured skutterudite materials were more stable than those of single-phase Ba0.3In0.2Co3.95Ni0.05Sb12 bulk materials. The evolution of TE properties indicates that the electrical and thermal conductivity decrease along with
an increase in the Seebeck coefficient with increasing quenching up to 2000 cycles. As a result, the dimensionless TE figure
of merit (ZT) of the nanostructured skutterudite materials remains almost constant. It can be concluded that these nanostructured skutterudite
materials have good thermal stability and are suitable for use in solar power generation systems. 相似文献
7.
Yunfeng Lai Baowei Qiao Jie Feng Yun Ling Lianzhang Lai Yinyin Lin Ting’ao Tang Bingchu Cai Bomy Chen 《Journal of Electronic Materials》2005,34(2):176-181
Nitrogen-doped Ge2Sb2Te5 (GST) films for nonvolatile memories were prepared by reactive sputtering with a GST alloy target. Doped nitrogen content
was determined by using x-ray photoelectron spectroscopy (XPS). The crystallization behavior of the films was investigated
by analyzing x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results show that nitrogen doping increases
crystallization temperature, crystallization-activation energy, and phase transformation temperature from fcc to hexagonal
(hex) structure. Doped nitrogen probably exists in the grain vacancies or grain boundaries and suppresses grain growth. The
electrical properties of the films were studied by analyzing the optical band gap and the dependence of the resistivity on
the annealing temperature. The optical band gap of the nitrogen-doped GST film is slightly larger than that of the pure GST
film. Energy band theory is used to analyze the effect of doped nitrogen on electrical properties of GST films. Studies reveal
that nitrogen doping increases resistivity and produces three relatively stable resistivity states in the plot of resistivity
versus annealing temperature, which makes GST-based multilevel storage possible. Current-voltage (I-V) characteristics of
the devices show that nitrogen doping increases the memory’s dynamic resistance, which reduces writing current from milliampere
to microampere. 相似文献
8.
Sintered Bi0.5(Na0.8K0.2)0.5TiO3 + x wt.% ZnO nanoparticle (BNKT–xZnOn) ceramics have been fabricated by conventional annealing with the aid of ultrasound waves for preliminary milling. Because of the presence of the liquid Bi2O3–ZnO phase at the eutectic point of 738°C, the sintering temperature decreased from 1150°C to 1000°C, and the morphology phase boundary of BNKT–xZnOn ceramics can be clarified by two separated peaks at (002)T and (200)T of 2θ in the x-ray diffraction (XRD) patterns. The improvement of ferroelectric properties has been obtained for BNZT–0.2 wt.% ZnOn ceramics by the increase of remanent polarization up to 20.4 μC/cm2 and a decrease of electric coercive field down to 14.2 kV/cm. The piezoelectric parameters of the ceramic included a piezoelectric charge constant of d 31 = 78 pC/N; electromechanical coupling factors k p = 0.31 and k t = 0.34, larger than the values of 42 pC/N, 0.12 and 0.13, respectively, were obtained for the BNKT ceramics. 相似文献
9.
Epitaxial PZT (001) thin films with a LaNiO3 bottom electrode were deposited by radio-frequency (RF) sputtering onto Si(001) single-crystal substrates with SrTiO3/TiN buffer layers. Pb(Zr0.2Ti0.8)O3 (PZT) samples were shown to consist of a single perovskite phase and to have an (001) orientation. The orientation relationship
was determined to be PZT(001)[110]∥LaNiO3(001)[110]∥SrTiO3 (001)[110]∥TiN(001)[110]∥Si(001)[110]. Atomic force microscope (AFM) measurements showed the PZT films to have smooth surfaces
with a roughness of 1.15 nm. The microstructure of the multilayer was studied using transmission electron microscopy (TEM).
Electrical measurements were conducted using both Pt and LaNiO3 as top electrodes. The measured remanent polarization P
r and coercive field E
c of the PZT thin film with Pt top electrodes were 23 μC/cm2 and 75 kV/cm, and were 25 μC/cm2 and 60 kV/cm for the PZT film with LaNiO3 top electrodes. No obvious fatigue after 1010 switching cycles indicated good electrical endurance of the PZT films using LaNiO3 electrodes, compared with the PZT film with Pt top electrodes showing a significant polarization loss after 108 cycles. These PZT films with LaNiO3 electrodes could be potential recording media for probe-based high-density data storage. 相似文献
10.
Shi-Jin Ding Min Zhang Wei Chen David Wei Zhang Li-Kang Wang 《Journal of Electronic Materials》2007,36(3):253-257
Metal-insulator-silicon capacitors have been fabricated using novel insulators of SiO2/HfO2-Al2O3-HfO2 (HAH)/Al2O3 and metallic HfN gate, exhibiting a program-erasable characteristic. The memory capacitor presents a large memory window
of 2.4 V under +12 V program/–14 V erase for 10 ms, no erase saturation, and sufficient electron- and hole-trapping efficiencies
such as an electron density of ∼7 × 1012 cm–2 under 13 V program for 0.5 ms and a hole density of ∼4 × 1012 cm–2 under –12 V erase for 0.5 ms. The observed properties are attributed to the introduction of high permittivity atomic-layer-deposited
HAH/Al2O3 as well as high work function HfN gate. The related mechanism is addressed accordingly. 相似文献
11.
Huanfu Zhou Hong Wang Kecheng Li Haibo Yang Minghui Zhang Xi Yao 《Journal of Electronic Materials》2009,38(5):711-716
The influence of BaCu(B2O5) (BCB) addition on the sintering temperature and microwave dielectric properties of ZnO-2TiO2-Nb2O5 (ZTN) ceramic has been investigated using dilatometry, x-ray diffraction, scanning electron microscopy, and microwave dielectric
measurements. A small amount of BCB addition to ZTN can lower the sintering temperature from 1100°C to 900°C. The reduced
sintering temperature was attributed to the formation of the BCB liquid phase. The ZTN ceramics containing 3.0 wt.% BCB sintered
at 900°C for 2 h have good microwave dielectric properties of Q × f = 19,002 GHz (at 6.48 GHz), ε
r = 45.8 and τ
f
= 23.2 ppm/°C, which suggests that the ceramics can be applied in multilayer microwave devices, provided that Ag compatibility
exists. 相似文献
12.
Naoyuki Takahashi Naoki Yoshii Shinichi Nonobe Takato Nakamura Masayuki Yoshioka 《Journal of Electronic Materials》2003,32(10):1107-1110
The ZrO2 films were deposited onto a Si(100) substrate using an alternate reaction of ZrCl4 and O2 under atmospheric pressure. It is found that the growth rate of ZrO2 film depends on the growth conditions, such as growth temperature, partial pressure of the sources being supplied, and exposure
time of the substrate to the gaseous sources. Self-limiting growth of the ZrO2 was achieved in the range of the growth temperature of 673–923 K. The x-ray diffractogram of the ZrO2 films showed a typical diffraction pattern assigned to the tetragonal polycrystalline phase. The obtained ZrO2 films were of smooth and uniform surface. It was found that the [O]/[Zr] ratio of the ZrO2 films are similar to that of the ZrO2 bulk. 相似文献
13.
High-temperature capacitor materials sintered at 1120°C were prepared in a BaTiO3 (BT)-Na0.5Bi0.5TiO3 (NBT)-Nb2O5-ZnO-CaZrO3 system. The Curie temperature of BaTiO3 was increased by NBT doping, and a secondary phase occurred when adding ≥5 mol% NBT. The effects of Nb2O5, ZnO, and CaZrO3 on the dielectric properties and the microstructure of BT ceramics doped with 1 mol% NBT were analyzed. The overall dielectric
constant decreased when the Nb2O5 content increased, and increased when the ZnO content increased. The dielectric constant peak at the Curie temperature was
effectively depressed, and a broad secondary dielectric constant peak appeared at 60°C when the ZnO concentration was ≥4.5 mol%.
Significant grain growth was observed by scanning electron microscope (SEM) analysis as the amount of ZnO increased. The high-temperature
capacitor specification (−55°C to +175°C, ΔC/C
25°C less than ±15%) is met when 7 mol% to 8 mol% CaZrO3 is added. 相似文献
14.
C. X. Wang N. Maeda M. Hiroki T. Tawara T. Makimoto T. Kobayahsi T. Enoki 《Journal of Electronic Materials》2005,34(4):361-364
AlGaN/GaN-based metal-insulator-semiconductor heterostructure field-effect transistors (MIS-HFETs) with Al2O3/Si3N4 bilayer as insulator have been investigated in detail, and compared with the conventional HFET and Si3N4-based MIS-HFET devices. Al2O3/Si3N4 bilayer-based MIS-HFETs exhibited much lower gate current leakage than conventional HFET and Si3N4-based MIS devices under reverse gate bias, and leakage as low as 1×10−11 A/mm at −15 V has been achieved in Al2O3/Si3N4-based MIS devices. By using ultrathin Al2O3/Si3N4 bilayer, very high maximum transconductance of more than 180 mS/mm with ultra-low gate leakage has been obtained in the MIS-HFET
device with gate length of 1.5 μm, a reduction less than 5% in maximum transconductance compared with the conventional HFET
device. This value was much smaller than the more than 30% reduction in the Si3N4-based MIS device, due to the employment of ultra-thin bilayer with large dielectric constant and the large conduction band
offset between Al2O3 and nitrides. This work demonstrates that Al2O3/Si3N4 bilayer insulator is a superior candidate for nitrides-based MIS-HFET devices. 相似文献
15.
Ternary rare-earth sulfides NdGd1+x
S3, where 0 ≤ x ≤ 0.08, were prepared by sulfurizing Ln2O3 (Ln = Nd, Gd) with CS2 gas, followed by reaction sintering. The sintered samples have full density and homogeneous compositions. The Seebeck coefficient,
electrical resistivity, and thermal conductivity were measured over the temperature range of 300 K to 950 K. All the sintered
samples exhibit a negative Seebeck coefficient. The magnitude of the Seebeck coefficient and the electrical resistivity decrease
systematically with increasing Gd content. The thermal conductivity of all the sintered samples is less than 1.9 W K−1 m−1. The highest figure of merit ZT of 0.51 was found in NdGd1.02S3 at 950 K. 相似文献
16.
Xinhua Zhu Jianmin Zhu Shunhua Zhou Zhiguo Liu Naiben Ming Shengguo Lu Helen Lai-Wah Chan Chung-Loong Choy 《Journal of Electronic Materials》2003,32(10):1125-1134
The (Ba1−xSrx)TiO3 (BST) ferroelectric thin films exhibit outstanding dielectric properties, even at high frequencies (>1 GHz), and large, electric-field
dielectric tunability. This feature makes them suitable for developing a new class of tunable microwave devices. The dielectric
properties and dielectric tuning property of BST thin films are closely related to the film compositions, substrate types,
and post-deposition process. The successful implementation of BST films as high-frequency dielectrics in electrically tunable
microwave devices requires a detailed understanding of both their processing and material properties. This paper will review
the recent progress of BST thin films as active dielectrics for tunable microwave devices. The technical aspects of BST thin
films, such as processing methods, post-annealing process, film compositions, film stress, oxygen defects, and interfacial
structures between film and substrate, are briefly reviewed and discussed with specific samples from the recent literature.
The major issues requiring additional investigations to improve the dielectric properties of BST thin films for tunable microwave
applications are also discussed. 相似文献
17.
Pawel Plonczak Anja Bieberle‐Hütter Martin Søgaard Thomas Ryll Julia Martynczuk Peter Vang Hendriksen Ludwig J. Gauckler 《Advanced functional materials》2011,21(14):2764-2775
Pulsed Laser Deposition (PLD) was used to prepare thin films with the nominal composition La0.58Sr0.4Co0.2Fe0.8O3‐δ (LSCF). The thin film microstructure was investigated as a function of PLD deposition parameters such as: substrate temperature, ambient gas pressure, target‐to‐substrate distance, laser fluence and frequency. It was found that the ambient gas pressure and the substrate temperature are the key PLD process parameters determining the thin film micro‐ and nanostructure. A map of the LSCF film nanostructures is presented as a function of substrate temperature (25–700 °C) and oxygen background pressure (0.013–0.4 mbar), with film structures ranging from fully dense to highly porous. Fully crystalline, dense, and crack‐free LSCF films with a thickness of 300 nm were obtained at an oxygen pressure lower than 0.13 mbar at a temperature of 600 °C. The obtained knowledge on the structure allows for tailoring of perovskite thin film nanostructure, e.g., for solid oxide fuel cell cathodes. A simple geometrical model is proposed, allowing estimation of the catalytic active surface area of the prepared thin films. It is shown that voids at columnar grain boundaries can result in an increase of the surface area by approximately 25 times, when compared to dense flat films. 相似文献
18.
M. V. Chukichev B. M. Ataev V. V. Mamedov Ya. I. Alivov I. I. Khodos 《Semiconductors》2002,36(9):977-980
The cathodoluminescent properties of ZnO films in ZnO/GaN/α-Al2O3 and ZnO/α-Al2O3 heteroepitaxial structures grown by chemical vapor deposition in a low-pressure flowing-gas reactor were studied and compared. A superlinear dependence of the excitonic-band intensity in the cathodoluminescence spectrum of the ZnO/GaN/α-Al2O3 structures on the electron-beam current is ascertained, which indicates that the emission is stimulated for relatively low thresholds of the excitation intensity. It is shown that the ZnO films grown on the GaN substrates exhibit a much more effective cathodoluminescence compared to the cathodoluminescence in the films grown on α-Al2O3. It was observed that the luminescent properties of ZnO layers in the ZnO/GaN/α-Al2O3 structures subjected to long-term heat treatment at 750°C in an oxygen atmosphere exhibit a high thermal stability. 相似文献
19.
J.S. Park J.H. Chang T. Minegishi H.J. Lee S.H. Park I.H. Im T. Hanada S.K. Hong M.W. Cho T. Yao 《Journal of Electronic Materials》2008,37(5):736-742
The polarity control of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular-beam epitaxy (P-MBE) was achieved by using a novel CrN buffer layer. Zn-polar ZnO
films were obtained by using a Zn-terminated CrN buffer layer, while O-polar ZnO films were achieved by using a Cr2O3 layer formed by O-plasma exposure of a CrN layer. The mechanism of polarity control was proposed. Optical and structural
quality of ZnO films was characterized by high-resolution X-ray diffraction and photoluminescence (PL) spectroscopy. Low-temperature
PL spectra of Zn-polar and O-polar samples show dominant bound exciton (I8) and strong free exciton emissions. Finally, one-dimensional periodic structures consisting of Zn-polar and O-polar ZnO films
were simultaneously grown on the same substrate. The periodic inversion of polarity was confirmed in terms of growth rate,
surface morphology, and piezo response microscopy (PRM) measurement. 相似文献
20.
Jiangying Peng Jian He Paola N. Alboni Terry M. Tritt 《Journal of Electronic Materials》2009,38(7):981-984
Filled skutterudites have long been singled out as one of the prime examples of phonon glass electron crystal materials. Recently
the double-filling approach in these materials has been attracting increased attention. In this study, Yb0.2In
y
Co4Sb12 (y = 0.0 to 0.2) samples have been prepared by a simple melting method and their thermoelectric properties have been investigated.
The power factor is increased dramatically when increasing the In content, while the lattice thermal conductivity is lowered
considerably, leading to a large increase of the ZT value. A state-of-the-art ZT value of 1.0 is attained in Yb0.2In0.2Co4Sb12 at 750 K. 相似文献