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铁电钛酸锶钡BaxSr1-xTiO3(BST)是一种拥有十分优越铁电/介电性能的材料,在可调谐微波器件方面具有很好的应用前景。本文概括介绍了BST薄膜的研究意义、基本结构、薄膜的制备方法,并针对可调谐微波器件应用需求,详细探讨了通过掺杂、组分梯度变化、纳米铁电多层薄膜以及将铁电BST与新型介电Bi2O3-ZnO-Nb2O5(BZN)薄膜相结合等对铁电薄膜性能进行优化的手段,最后对该领域的前沿问题从材料研究层面作了小结与展望。 相似文献
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近年来,铁电HfxZr1-xO2(HZO)薄膜受到越来越多的关注,但是铁电层与电极材料层以及铁电层与半导体衬底层之间的界面问题并没有得到解决,阻碍了HZO薄膜的进一步应用。总结了通过引入不同介电层材料,如Al2O3、ZrO2、HfO2、Ta2O5等,调节HZO薄膜铁电性能的方法及其机理;详细介绍了各种介电层材料作为封盖层对HZO薄膜铁电性能的影响,如对HZO薄膜提供平面内应力、控制铁电层的晶粒尺寸及作为铁电层形核核心的作用;最后,总结并展望了利用介电层调控HZO薄膜铁电性能的一般规律,为后续相关研究的开展提供了指导。 相似文献
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MCM—D中薄膜介质层主要是用于多层布线的层间绝缘及埋置电容器介质层。介质膜的制备及刻蚀工艺是(MCM—D)薄膜多层布线工艺的基础和关键技术。聚酰亚胺具有高热稳定性、低介电系数、良好的平坦性及可加工性,是用的最多的薄膜介质材料。本文通过对聚酰亚胺的选择、旋涂、固化工艺控制解决了聚酰亚胺介质膜的制备及稳定性难题。通过精确控制腐蚀时间来实现通孔的湿法刻蚀。 相似文献
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钛酸锶钡(BST)组分梯度多层厚膜具有较好的综合介电性能,包括适中的介电常数、高的介电温度系数、低的介质损耗等,日益成为红外探测器、微波调制器件的重要候选厚膜材料.采用改进的溶胶-凝胶(Sol-Gel)法在Pt/Ti/SiO2/Si基片上制备Mn掺杂6层不同组分梯度BST厚膜.厚约5 μm.研究了梯度BST厚膜的微观结构及其介电性能.X-射线衍射(XRD)分析表明,当热处理温度为750℃时,得到完整钙钛矿结构的厚膜材料.扫描电镜(SEM)电镜显示,厚膜表面晶粒大小均匀,排列紧密,致密性好,梯度BST厚膜的介电峰温区覆盖常温,介电常数峰值为920,介电损耗约为1.8×10-2. 相似文献
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钛酸锶钡(BST)组分梯度多层厚膜具有较好的综合介电性能,包括适中的介电常数、高的介电温度系数、低的介质损耗等,日益成为红外探测器、微波调制器件的重要候选厚膜材料.采用改进的溶胶-凝胶(Sol-Gel)法在Pt/Ti/SiO2/Si基片上制备Mn掺杂6层不同组分梯度BST厚膜.厚约5 μm.研究了梯度BST厚膜的微观结构及其介电性能.X-射线衍射(XRD)分析表明,当热处理温度为750℃时,得到完整钙钛矿结构的厚膜材料.扫描电镜(SEM)电镜显示,厚膜表面晶粒大小均匀,排列紧密,致密性好,梯度BST厚膜的介电峰温区覆盖常温,介电常数峰值为920,介电损耗约为1.8×10-2. 相似文献
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近年来,铁电薄膜制备技术的迅速发展使得人工介电超晶格的生长成为现实。简要介绍了有关介电多层膜和人工介电超晶格的制备、结构和性能的研究状况,讨论了进一步研究需解决的问题。 相似文献
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钛酸锶钡(BaxSr1-xTiO3,简称BST)薄膜具有非线性强、漏电流小、居里温度可调等特点,因而在介质移相器、压控滤波器等方面有着广泛的应用前景。笔者对BaxSr1-xTiO3(x=0.45~0.90)系列陶瓷的晶体结构和介电性能、膜厚均匀性控制、BST薄膜的微结构(包括组成、晶体结构和电畴等)和介电非线性尺度效应、铁电薄膜介电非线性模型、薄膜型介质移相器的设计和制作等重要问题进行了研究,取得了以下研究结果:通过研究靶基中心不重合的磁控溅射系统,建立了平面磁控溅射膜厚分布的数学模型,提出了采用T=∫Ld(x,y)ds=∫0td(ξ(t),ψ(t))ξ'2(t)+ψ'2(t)dt来描述靶基中心不重合的平面磁控溅射的膜厚分布情况。在靶基距为72mm、公自转转速比为5.3的条件下,采用自行设计的射频磁控溅射设备和φ100mm靶材制备的BST薄膜膜厚均匀性偏差为2.8%。采用压电力显微镜(PFM)研究了BST薄膜中电畴的类型和尺寸。不仅证实BST薄膜中存在90°铁电畴,而且确定了BST薄膜由多畴转变为单畴结构的晶粒临界尺寸(单畴临界尺寸)为31nm左右。通过研究BST薄膜的介电非线性尺度效应,发现晶粒尺寸和膜厚对薄膜的介电非线性具有重要的作用。随着晶粒尺寸和膜厚的增加,BST薄膜的介电系数、介电系数变化率都逐渐增大。晶粒尺寸对单畴态薄膜的介电系数电压变化率和矫顽场强影响特别显著,而对多畴态薄膜的介电系数电压变化率和矫顽场强影响不明显。在上述实验研究的基础上,对铁电材料的介电非线性机理进行了研究。首先,从简单、实用的角度出发写出表征P(E)和ε(E)非线性的数学多项式,根据介电偏压特性曲线和电滞回线的特征值和连续性原理,给出边界条件和初始条件,解出表达式中的各项系数,从而建立了铁电晶体的介电非线性模型。然后,采用理想的晶粒–晶界几何模型,画出铁电陶瓷材料的等效电路,引入晶粒和晶界的大小,从而建立了铁电陶瓷的介电非线性模型。再采用理想二极管等效界面势垒,得到薄膜型平板电容器等效电路,引入膜厚和界面厚度两个尺度变量,从而建立了铁电薄膜的介电非线性模型。最后,利用文献的数据和曲线对模型进行了验证,模拟得到的曲线与实验得到的曲线变化趋势基本一致,表明该模型可以较好地解释铁电材料(包括陶瓷和薄膜)的介电非线性特性及其随晶粒大小、膜厚和界面厚度等尺度变化的规律。对薄膜型介质移相器的设计、制作和测试进行了研究。采用ADS和HFSS软件进行仿真,设计出了分布式电容负载型铁电薄膜介质移相器的电路结构和各部分的尺寸;采用改进的剥离工艺,制作出了电极线条整齐的铁电薄膜介质移相器;采用矢量网络分析仪,在频率为35GHz、控制电压为40V条件下,测得介质移相器的移相度为180°,插损为9.7dB。 相似文献
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研究了特异结构锆钛酸铅PbZr0.38Ti0.62O3(PZT)多层膜的铁电和介电特性.同均一相PZT薄膜材料相比,由致密层和多孔层交替排列形成的近周期PZT多层膜具有铁电、介电增强效应.在100V极化电压下,多层膜的平均剩余极化强度达42.3μC/cm2,矫顽场为43kV/cm.大的极化强度值归因于大的膜厚和多孔结构有效释放膜内张应力的结果.室温低频限下,PZT多层膜的表观相对介电常数超过2000.极为有趣的是,在所研究的频率范围,PZT多层膜具有两种截然不同的介电驰豫.低频介电损耗峰源自空间电荷极化;而遵从Arrhenius律的高频介电响应可能同与氧空位Vo"相关的极性缺陷复合体有关. 相似文献
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Jiagang Wu Dingquan Xiao Jiliang Zhu Jianguo Zhu Junzhe Tan Qinglei Zhang 《Microelectronic Engineering》2008,85(2):304-307
The Pb(Zr0.20Ti0.80)O3/(Pb1−xLax)Ti1−x/4O3 (x = 0, 0.10, 0.15, 0.20) (PZT/PLTx) multilayered thin films were in situ deposited on the Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by RF magnetron sputtering technique with a PbOx buffer layer. With this method, all PZT/PLTx multilayered thin films possess highly (1 0 0) orientation. The PbOx buffer layer leads to the (1 0 0) orientation of the multilayered thin films. The effect of the La content in PLTx layers on the dielectric and ferroelectric properties of the PZT multilayered thin films was systematically investigated. The enhanced dielectric and ferroelectric properties are observed in the PZT/PLTx (x = 0.15) multilayered thin films. The dielectric constant reaches maximum value of 365 at 1 KHz for x = 0.15 with a low loss tangent of 0.0301. Along with enhanced dielectric properties, the multilayered thin films also exhibit large remnant polarization value of 2Pr = 76.5 μC/cm2, and low coercive field of 2Ec = 238 KV/cm. 相似文献
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The paper presents the comparative analysis of effect of hydrochloric (HCl), hydrofluoric (HF) acid catalyst and organic material methylmethacrylate (MMA) on dielectric constant of thin films. The dielectric constant of thin film obtained by using HCl catalyst is 3.63 which have been successfully reduced to 2.97 for hybrid thin films via incorporation of carbon. The deposited low k dielectric thin films observed to have good adhesion with p-silicon substrate and hence pertinent for interlayer dielectric (ILD) in ultra-large scale integrated (ULSI) circuits applications. The deposited films have been characterized by ellipsometer for refractive index, further material compositions have been studied by using Fourier transform infrared (FTIR) spectroscopy and energy dispersive spectroscopy (EDAX). 相似文献
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Amorphous chalcogenide thin films were fabricated by the pulsed laser deposition technique. Thereafter, the stacks of multilayered thin films for reflectors and microcavity were designed for telecommunication wavelength. The prepared multilayered thin films for reflectors show good compatibility. The microcavity structure consists of Ge25Ga5Sb10S65 (doped with Er3+) spacer layer surrounded by two 5-layer As40Se60/Ge25Sb5S70 reflectors. Scanning/transmission electron microscopy results show good periodicity, great adherence and smooth interfaces between the alternating dielectric layers, which confirms a suitable compatibility between different materials. The results demonstrate that the chalcogenides can be used for preparing vertical Bragg reflectors and microcavity with high quality. 相似文献
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André Knoesen Ge Song Willi Volksen Elbert Huang Teddie Magbitang Linda Sundberg James L. Hedrick Craig J. Hawker Robert D. Miller 《Journal of Electronic Materials》2004,33(2):135-140
The dielectric properties are reported for nanoporous thin films of poly(methyl silsesquioxane) (MSSQ) for use as an ultralow,
dielectric intermetal insulator. Direct experimental conformation is provided that the films have low dielectric constants
with low loss up to 10 GHz. Low-frequency measurements are also reported. 相似文献
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As feature sizes of circuits and devices approach 100 nm and chip frequencies climb into the upper GHz to THz range, it becomes increasingly important to have a convenient method of characterizing properties of thin dielectric films in the GHz to THz frequency range. THz time-domain spectroscopy provides a non-contact, non-destructive and highly sensitive optical tool to characterize the dielectric and optical properties of micron to nanometer scaled thin films at GHz and THz frequencies. The measurement of the dielectric and the optical properties of nanometer scaled dielectric films is performed using the THz differential time-domain spectroscopy. The real and imaginary parts of the complex dielectric constants and the optical constants of a variety of nano thin films are measured at GHz and THz frequencies. 相似文献