铁电薄膜的微图形化研究

铁电薄膜在微电子和光电子技术中有着重要的或潜在的应用,可以制作随机存取存储器,热释电阵列探测器,铁民微电子机械系统等,在这些器件的制作过程中,铁电薄膜的微图形化是非常重要的一环,本文简要介绍了几种重要的铁电薄膜微图形化方法及有关研究结果,并比较了这些方法的优缺点。     

铁电存储器及其疲劳机制的研究

简述了铁电材料的结构及其性能,比较了铁电存储器的各种制备工艺的优缺点及发展前景;同时介绍了目前较为先进的铁电储存器的优良的读,写等特性及国际市场发展动态对当今高度发展的信息社会的重要作用。同时探讨了铁电材料的疲劳机制研究现状及其深入研究的所应遵循的技术路线。     

铁电陶瓷的技术进展及其应用

铁电陶瓷经过多年研究与开发，已成为引人注目的新型材料。以前主要用于军事和航天行业，随着生产技术的不断进步与成熟，生产成本不断降低，具有特殊性能的铁电陶瓷应用领域不断扩大，现已复盖电子、通信、化工、冶金、医学、计算机和汽车行业，产品包括高介电常数电容器、压电声纳和超声波转换器、广播通信用滤波器、热电转换安全监视装置、医学诊断转换器、立体声高频扬声器、气体点火器、正温度系数（ＰＴＣ）传感器和开关，超声马达、光电光阀、薄膜电容器、铁电薄膜存储器、位移传动器等。 铁电陶瓷产品的开发越来越受到国内外技术界…     

Pb(Zr,Sn,Ti)O3中组份变化对反铁电-铁电相变的影响

探讨了掺铌Ｐｂ（Ｚｒ,Ｓｎ,Ｔｉ）Ｏ３反铁电陶瓷中,组份变化对晶体结构及电场诱导反铁电－铁电相变性能的影响,分析结果表明;在Ｐｂ０．９９Ｎｂ０．０２〖（Ｚｒ１－ｘＳｎｘ）１－７Ｔｉｙ〗０．９８Ｏ３反铁电陶瓷中,ｙ增加,反铁电四方相晶轴比减小,增加晶胞体积,诱导反铁电－铁电相变的开关电场强度降低,ｘ增加,反铁电四放相的晶轴比ａ／ｃ铁电相变的反铁电相区。     

BST铁电薄膜的制备、应用及其研究进展

综述了钛酸锶钡（BST）铁电薄膜的4种制备工艺：磁控溅射（Magnetron sputtering）法、金属有机物化学气相沉积（MOCVD）法、脉冲激光淀积（PLD）法,以及溶胶-凝胶（Sol-Gel）法.并介绍了BST铁电薄膜在动态随机存储器、非致冷红外探测器热成像、移相器等方面的应用及其研究进展.     

组成对锆钛酸铅铁电薄膜电性能影响的研究进展

锆钛酸铅材料因具有优异的介电、压电和铁电性被广泛用于制作电容器、压电器件和铁电随机存储器等功能器件.本文综述了锆钛酸铅铁电薄膜材料中锆钛比、掺杂种类及掺量对其介电性和铁电性的影响,并提出了亟待解决的问题.     

铁电薄膜材料的性能,应用和发展前景

本文阐述了铁电薄膜的铁电、压电、热释电三个重要性质，和它们在微电子学和光电子学的应用，并展望了铁电薄膜未来发展前景。     

铁电液晶及其分子结构的特征

阐述了铁电液晶及其分子结构的特征,介绍了近十年来铁电液晶的发展情况,并较系统地讨论了液晶的分子结构对其铁电性能的影响。     

铁电薄膜光伏效应研究进展

铁电材料由于具有反常的光伏效应(光生电场高达103~105 V/cm),理论上存在较高的光电转换效率,在太阳能光伏领域具有潜在的应用前景而备受关注。然而,由于铁电材料带隙通常较大、导电性差等因素导致其光生电流较低、光电转换效率还有待进一步提高。弄清铁电光伏效应是增强其转换效率的重要前提。但关于铁电材料光伏效应的起源目前还没有定论,其机制也一直存在争议。基于以上考虑,本文综述了铁电薄膜光伏效应的研究进展,详细阐述了影响光伏效应的各种因素及铁电薄膜光伏效应的机制,并提出了亟待解决的问题。     

铁电薄膜的制备工艺及发展趋势

随着陶瓷材料新技术生产发展的需求,多功能的铁电薄膜材料日益引起科研人员的广泛关注,并成为近年来研究的热点。论述了铁电薄膜的发展过程、种类、性能以及应用,着重介绍了铁电薄膜的制备方法,并指出了铁电薄膜的发展趋势。     

Non–ferroelectric intercalation structure based on Aurivillius phase Bi4Ti3O12: A research arena to achieve high energy storage performance

High density energy capacity is the benchmark of electronic industry, and its improvement is on the way. Here, the BaCaBi₄Ti₅O₁₈ films present high efficient energy storage trait, which is originated from ferroelectric/non–ferroelectric intercalation structure. The emergent of large gradient elastic energy in ferroelectric/non–ferroelectric intercalation structure not only crushes the ferroelectric domains, but also modulates space charges accumulation. Both factors contribute to the high polarization and intense breakdown strength. The contrast experiments were conducted by single ferroelectric intercalated structure Bi₅Ti₃FeO₁₅ films, which show almost non ferroelectric energy storage behavior. The finite element simulations are consistent with the experimental evidences. The present results may facilitate a way for structural design of Aurivillius family, which is capable of acting as remarkable energy storage tasks.     

塑料内存的发展现状

塑料内存是传统硅芯片材料的替代品。相比于硅材料,塑料内存的性能更佳,如具有硅芯片难以比拟的柔软性和透明性,成本也更低。塑料内存的信息存储单元目前有铁电聚合物、聚噻吩或金属粒子掺杂的聚合物等,上述信息存储单元可采用印刷、打印、涂布等方式处理在柔性基材上,且存储的信息可以一次写入、多次读出,或多次写入、多次读出。     

铁电薄膜的材料系统与功能性质

集成铁电体把铁电材料与集成半导体技术联合起来,以发展出一批新的电子器件.铁电薄膜在其中发挥着非挥发性记忆、热释电、压电、光折变、抗辐射、声学的和/或介电的功能性质.在不同的器件应用中,铁电薄膜的材料体系是不相同的.在非挥发性存贮器(NVRAM)中,PZT薄膜面临着SrBi2Ta2O9(SBT)系列铁电体的强力挑战;Ba1-xSrxTiO3(BST)则可能出现在下一代高密度动态随机存贮器(DRAM)中.金属氧化物电极和/或过渡层可以克服Pt电极面临的一些问题,并有助于铁电薄膜的外延生长.     

电子陶瓷材料及产品与技术解读

电子陶瓷在信息的检测、转化、处理和存储显示中应用广泛,是信息技术中基础元器件的关键材料。针对电子陶瓷材料的功用特点及应用领域,分别介绍了电子绝缘装置陶瓷,电子电容器陶瓷,电子铁电陶瓷和半导体陶瓷以及电子快离子陶瓷的结构原理、性能优势和制造工艺等,同时指出了电子陶瓷材料的发展前景。     

Ferroelectric polymers for non‐volatile memory devices: a review

Ferroelectric memories have attracted great attention for data storage, and ferroelectric polymers have been widely studied with the development of flexible and wearable devices. The multifunctional capabilities, non‐volatile memory state, low power consumption, long durability, fast switching, chemical stability and mechanical flexibility make them good candidates for various memories, such as ferroelectric tunnel junctions and diodes, ferroelectric capacitors, resistive memories and field‐effect transistors. Here, recent advances in the research of these ferroelectric polymer memories are summarized, and challenges in the development of smart electronics are also discussed. © 2020 Society of Chemical Industry     

Improved energy storage density and energy efficiency of Samarium modified PMNT electroceramic

We report the improved energy storage density and efficiency after 2.5% of Samarium substitution in ferroelectric Pb[(Mg_1/3Nb_2/3)_0.80Ti_0.20]O₃ (PMNT) electroceramic. The microstructure and surface morphology were analyzed and correlated with various functional properties. The energy storage density, leakage current density, ferroelectric and dielectric properties were investigated thoroughly, indicating that Samarium's substitution significantly modified the microstructure, the dielectric strength, breakdown electric field, and turned ferroelectric PMNT to relaxor ferroelectrics. Due to the relaxor nature, the gap between remanent polarization and maximum polarization increases with the substitution of Samarium in PMNT matrix, which further increases the recoverable energy storage density and energy efficiency. A nearly 100% increase in recoverable energy density and efficiency was obtained at an electric field strength of 35 kV/cm at room temperature (～296 K). The electroceramic shows maximum energy density near the ferroelectric phase transition temperature (325 K–345 K) region and provides a moderate energy storage density for possible applications in power microelectronics.     

Ferroelectric domains and luminescent properties of Pr3+-doped Ca2Nb2O7 ceramics

Inorganic luminescent materials based on photoluminescence (PL) and thermoluminescence (TL) display considerable potential applications for optical anti-counterfeiting devices. Ca_2−xNb₂O₇:xPr³⁺ (x = 0.00075, 0.001, 0.002, 0.003, 0.004) ferroelectric ceramics have been fabricated. The basic crystal structure, local ferroelectricity and PL/TL properties of the ceramics have been investigated in this study. The PFM measurement proves that the grains in the prepared ceramics are monodomain state. Furthermore, the synthesized phosphors are embedded into polydimethylsiloxane (PDMS) matrix to fabricate a novel optothermal responsive device with high elasticity, transmittance and heat resistance. The PL and TL photographs of the designed device further demonstrate that the device is promising in practical applications such as optical anti-counterfeiting and information storage.     

Ultrahigh energy storage density and charge-discharge performance in novel sodium bismuth titanate-based ceramics

Lead-free ferroelectric ceramics are very suitable for electrostatic energy storage capacitors due to their outstanding characteristics of high charge-discharge speed, high power density, and environmental friendliness. Herein, a novel material system as (1−x)Na_0.5Bi_0.5TiO₃-xCaZr_0.5Ti_0.5O₃ (NBT-CZT, x = 0, 0.05, 0.10, 0.12, 0.15, and 0.20) was designed and prepared for dielectric energy storage ceramics. It demonstrated that the CZT additives induced a phase transition for the NBT ceramics, from ferroelectric to relaxor ferroelectric. In particular, extremely high stored energy storage density (6.92 and 5.37 J/cm³), high recoverable energy storage density (4.77 and 4.37 J/cm³), and moderate efficiency (69.0% and 81.4%) were achieved in both the samples of x = 0.12 and x = 0.15, respectively. The ceramics exhibited excellent stability of energy storage performance covering a wide temperature (25°C–200°C) and frequency (0.5–50 Hz) range, and also fatigue cycles up to 10⁵. Additionally, the NBT-CZT ceramics had a fast discharge speed (t_0.9 < 100 ns) and high power density (24.2 MW/cm³, E = 100 kV/cm, x = 0.15), and the charge-discharge process remained stable even when the measured temperature was up to 160°C. Therefore, the NBT-CZT ceramics have the potential to be utilized in electrostatic energy storage applications.     

Shock-driven depolarization behaviors and electrical output in BiAlO3-doped Bi0.5Na0.5TiO3 ferroelectric ceramics

Ferroelectric materials under shock compression can generate current and power by a drastic change of the remnant polarizations and surface bound charge. This behavior has been employed in applications involving nuclear fusion trigger, energy storage devices, and high pulse power sources. Despite the large power output in lead-containing ferroelectrics, lead-free materials are highly desirable owing to the environmental concerns. Herein, the phase transition behaviors and current outputs of 0.92Bi_0.5Na_0.5TiO₃-0.08BiAlO₃ (BNT-8BA) materials are studied under high pressure. The BNT-8BA ferroelectric ceramics can be completely depolarized from polar to the nonpolar state under shock compression, resulting in a current output in the external circuit. The phase-transition-induced depolarization pressures of BNT-8BA are lower than those of the pure Bi_0.5Na_0.5TiO₃ under both dynamic and static high-pressure loads. These results can allow the understanding of the high-pressure behavior of BNT-8BA for application as ferroelectric pulsed power supply.     

Ultrahigh storage density achieved with (1-x)KNN-xBZN ceramics

A series of (1-x)K_0.5Na_0.5NbO₃-xBa(Zn_1/3Nb_2/3)O₃ ((1-x)KNN-xBZN) nanostructural ceramics was successfully synthesised via solid-state reactions. These nanostructural ceramics exhibited high energy storage density compared with pure KNN ceramics. Further analysis of their dielectric/ferroelectric properties and structures revealed that the addition of BZN alloy disrupted the long-range order of the ferroelectric lattice of pure KNN and favoured the formation of ferroelectric islands and/or polar nano-regions. Consequently, the nanostructured ceramic with x = 0.05 exhibited ultrahigh energy storage density, W, of approximately 9.14 J/cm³ and recoverable energy storage density, W_rec, of approximately 4.87 J/cm³ under a fairly low applied electrical field (220 kV/cm). These values exceed the highest values ever reported for KNN-based bulk ceramics. In addition, both excellent fatigue endurance (10⁵ cycles) and temperature stability (Δε'/ε_100°C < 15 % in the range 30–390 °C) were realised with the 0.97KNN-0.03BZN ceramic. Their excellent energy storage properties render KNN-based ceramics potential candidates for application in pulsed-power systems.