共查询到19条相似文献,搜索用时 797 毫秒
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介质材料的相对复介电常数可以用ε_r=ε(1-jtgδ)表示,式中ε为相对介电常数,tgδ为损耗角正切.我们在日常科研和生产中经常用到某些陶瓷、塑料或玻璃钢等介质材料,它们的相对介电常数小于10,损耗角正切小于0.1,可以称之为低介电常数、低损耗介质 相似文献
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为了降低CaCu3Ti4O12(CCTO)陶瓷材料的介质损耗,采用传统固相反应法制备了组分为CaCu3–yZry/2Ti4O12(CCZTO)的陶瓷样品。研究了ZrO2掺杂对CCTO陶瓷性能的影响。结果表明:所制CCZTO陶瓷样品在维持了CCTO陶瓷材料介电常数大、低频介电常数随频率和温度变化小的优点的同时,介质损耗大幅降低;其介电常数和介质损耗的指标满足美国电子工业协会EIAZ5U标准,而温度系数αc性能指标优于EIAX7A标准所规定的±55×10–6/℃,是一种综合性能技术指标优良的新型高介电常数陶瓷材料。 相似文献
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《电子元件与材料》2017,(12):11-15
采用溶胶-凝胶法制备了非晶SiO_2粉体,并研究了不同溶液配比对所得粉体粒度和分散性的影响。结果表明:当H2O和TEOS摩尔比为20:1和40:1时,可以制备出分散性较好的非晶SiO_2粉体,其粒度分别为700 nm和120 nm。在此基础上,研究了不同原料粉体对SiO_2材料烧结特性和微波介电性能的影响规律。研究发现:粉体粒度较小,有利于降低SiO_2材料的烧结温度,提高其相对密度,抑制其析晶现象。当烧结温度为1050~1200℃时,SiO_2材料的相对介电常数为2.50~3.75,Q·f值为9850~61 272 GHz,τf值的变化范围为±15×10–6/℃(温度范围为25~85℃),适合用于制作微波介质基板。 相似文献
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采用聚合物前驱体法制备了单一铋系层状钙钛矿相SrBi2Ta2O9粉体,研究了不同烧成温度对SrBi2Ta2O9陶瓷相结构和介电、铁电性能的影响。结果表明,随着烧成温度的升高,晶粒沿c轴择优取向趋势增强;不同烧成温度下陶瓷介电常数和损耗均随频率升高而降低,1000℃时陶瓷有最大介电常数和较小的损耗,且陶瓷有较大的剩余极化值和较小的矫顽电场,分别为3.884μC/cm2和25.37kV/cm。不同Ca掺杂量掺杂后,SrBi2Ta2O9陶瓷的介电常数、损耗和剩余极化值均显著降低。 相似文献
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采用射频磁控溅射法分别在Ar/N2和Ar/O2气氛中制备了厚度为80~300nm的SiMon薄膜,研究了沉积功率对SiMon薄膜的介电性能的影响.发现在Ar/N2气氛中沉积的Sialon薄膜具有较高的介电常数,漏电流密度和介电损耗也稍大.在Ar/N2气氛下沉积的SiMon薄膜的介电常数在4.8~8.5之间,反映介电损耗的参数△Vy在0.010~0.045V之间,在50MV/m直流电场下的正、反向漏电流密度在10-10~10-8数量级,击穿场强在201~476 MV/m;在Ar/O2气氛下沉积的SiMon薄膜的介电常数在3.6-5.3之间,反映介电损耗的参数△Vy小于0.01V,在50MV/m直流电场下的正、反向漏电流密度在10-10~10-9数量级,击穿场强在260~305 MV/m之间.该绝缘薄膜应用于以Zn2SixGe1-xO4:Mn为发光层的无机EL显示器件和以IGZO为有源层的TFT器件中获得了较好的结果. 相似文献
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High dose-rate plasma ion implantation (PII) has been utilized to produce low dielectric constant (k) SiO2 films for high quality interlayer dielectrics. The SiO2 films are fluorine-doped/carbon-doped by PII with CF4 plasma in an inductively-coupled plasma (ICP) reactor. It is found that the use of CF 4 doping results in exceptional dielectric properties which differ significantly from fluorinated SiO2. The dielectric constant of the SiO2 film is reduced from 4.1 to 3.5 after 5 minute PII, other electrical parameters such as bulk resistivity and dielectric breakdown strength are also improved 相似文献
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Al2O3、ZrO2、Ta2O5和La2O3薄膜在栅介质、无机EL介质和光学薄膜方面有着重要用途,但对其复合薄膜介电性能方面的研究很少。文章采用电子束共蒸发法制备了厚度分别为414nm和143nm的Al2O3-La2O3(ALO)和ZrO2-Ta2O5(ZTO)复合薄膜,用Sawyer—Tower电路测得介电常数分别为17和34,反映介电损耗的参数△Vy分别为0.013V和0.56V,击穿场强分别为128MV/m和175MV/m,在50MV/m场强下,ALO的正、反向漏电流密度分别为3.1×10-5/cm2和4.1×10-5A/cm2,ZTO的正、反向漏电流密度分别为3.9×10-5/cm2和3.7×10-5A/cm2。另外,实验还与电子束蒸发和反应溅射制备的Al2O3、ZrO2、Ta2O5的介电性能做了比较,结果表明,上述复合薄膜单独作为无机EL绝缘层是不合适的。 相似文献
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Topological‐Structure Modulated Polymer Nanocomposites Exhibiting Highly Enhanced Dielectric Strength and Energy Density 下载免费PDF全文
Penghao Hu Yang Shen Yuhan Guan Xuehui Zhang Yuanhua Lin Qiming Zhang Ce‐Wen Nan 《Advanced functional materials》2014,24(21):3172-3178
Dielectric materials with high electric energy densities and low dielectric losses are of critical importance in a number of applications in modern electronic and electrical power systems. An organic–inorganic 0–3 nanocomposite, in which nanoparticles (0‐dimensional) are embedded in a 3‐dimensionally connected polymer matrix, has the potential to combine the high breakdown strength and low dielectric loss of the polymer with the high dielectric constant of the ceramic fillers, representing a promising approach to realize high energy densities. However, one significant drawback of the composites explored up to now is that the increased dielectric constant of the composites is at the expense of the breakdown strength, limiting the energy density and dielectric reliability. In this study, by expanding the traditional 0–3 nanocomposite approach to a multilayered structure which combines the complementary properties of the constituent layers, one can realize both greater dielectric displacement and a higher breakdown field than that of the polymer matrix. In a typical 3‐layer structure, for example, a central nanocomposite layer of higher breakdown strength is introduced to substantially improve the overall breakdown strength of the multilayer‐structured composite film, and the outer composite layers filled with large amount of high dielectric constant nanofillers can then be polarized up to higher electric fields, hence enhancing the electric displacement. As a result, the topological‐structure modulated nanocomposites, with an optimally tailored nanomorphology and composite structure, yield a discharged energy density of 10 J/cm3 with a dielectric breakdown strength of 450 kV mm–1, much higher than those reported from all earlier studies of nanocomposites. 相似文献
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采用激光烧结快速合成方法成功制备出负热膨胀ZrW2O8材料。在扫描电镜(SEM)下观察样品形貌,显示出激光烧结ZrW2O8样品颗粒细小、分布均匀,晶粒大小在10 nm左右。X射线衍射(XRD)和拉曼光谱分析表明,激光法烧结可以有效地合成ZrW2O8,样品表面仅包含α-ZrW2O8,而样品内部除包含主要成分α-ZrW2O8外,还有γ-ZrW2O8相存在,可能与激光烧结过程中圆坯片内部存在极大的应力有关。同时分析了激光扫描速率对样品性能的影响,结果表明,激光烧结合成ZrW2O8时,在合适的激光功率密度下,适当地降低扫描速度,可以有效地减少γ相的产生。 相似文献
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Yun-Hi Lee Byeong-Kwon Ju Dong-Ho Kim Myung-Hwan Oh 《Electron Devices, IEEE Transactions on》2001,48(4):653-660
We introduced thin-film electroluminescent cells (TFEL) with a new multilayered-BaTiO3 layer for the low-voltage driven devices. We begin by simulating the basic parameters for TFEL devices in electrostatic boundary condition and point out how the insulator parameters influence the typical operating properties of the devices. Next, we performed the voltage accelerated breakdown testing of the multilayered-BaTiO3 having both high dielectric constant and high breakdown strength. The time-zero-breakdown distribution is shown to be dependent on surface roughness, while the long-term failure studied by time-dependent-dielectric breakdown technique at high field is dependent on the bulk characteristics, i.e., transition layers within m-BT films. Thirdly, the TFEL devices were prepared using the multilayered-BaTiO3 as dielectric materials. We observed a decrease of turn-on voltage with increasing thickness and the increase of the maximum overvoltage. Finally, typical symmetric capacitance-voltage (C-V) and internal charge-phosphor field characteristics were obtained for the device with thin m-BT layers. With increasing thickness of m-BT the significant asymmetry with respect to the applied voltage polarity was observed. This is a main difference as compared with the symmetric characteristics of conventional TFEL devices with low dielectric constant insulators. The experimental results indicate the fact that a selection of the thickness of upper m-BT and their deposition process would strongly affect the interfacial characteristics as well as bulk characteristics of an as-grown ZnS:Pr, Ce layer 相似文献
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High frequency microelectronic and optoelectronic device packaging requires the use of substrate and encapsulation materials having a low dielectric constant, low dielectric loss and high volume resistivity. Most packaging materials are polymer-ceramic composites. A clear understanding of the broadband dielectric properties of composite materials is thus of great current importance for the effective development of high frequency packaging materials and optimized package design. Toward this goal, a general framework for understanding the dielectric properties of packaging materials was recently developed in which the dielectric constant of polymer-ceramic composite materials is characterized by the electrical properties of the polymer phase, the filler phase and an interphase region within the composite system. However, for this framework to be a viable tool for tailoring the dielectric properties of packaging materials, one must understand the dielectric properties of the polymer-filler interphase region, which represents a region of polymer surrounding and bonded to the surface of each filler particle having unique dielectric and physical characteristics. This work presents a model to explain and predict the dielectric properties of the composite interphase region based on dipole polarization theory. 相似文献