Ta2O5介质膜性能对液体钽电容器性能的影响

叙述了钽电解电容器阳极Ta2O5介质膜的形成过程,分析了电解液闪火与氧化膜击穿的微观过程。利用扫描电子显微镜(SEM)分析了阳极氧化后及产品失效后阳极钽芯表面介质膜的微观结构,并对液钽电容器失效机理进行了探讨。结果表明,介质膜内杂质或缺陷处O2-放电产生的电子发射是电解液闪火和氧化膜击穿的前驱点;在高电场或高温度的作用下,介质膜的场致晶化和热致晶化是液体钽电解电容器失效的主要模式。     

大容量液体钽电容器高温负荷时失效机理研究

对CA35型160 V/47μF液体钽电解电容器进行2 000 h/85℃高温负荷耐久性试验。通过对失效样品的电性能的测试及对样品阳极钽芯表面氧化膜的结构变化的SEM分析,探讨了其失效机理。表明在高温负荷条件下,由于场致晶化和热致晶化的作用,Ta2O5介质膜由无定形态转化为结晶态,介质膜结构发生畸变是引起产品失效的主要原因。     

有机固体电解质钽电容器的失效机理及预防措施

有机固体电解质钽电容器具有等效串联电阻(Res)小,温和的失效模式和高频特性好等特点,在很多电子信息领域都显示出独特的优势。结合传统钽电解电容器的失效机理和大量的统计实验结果,对有机电解质钽电容器的失效模式进行了详细分析,指出了介质氧化膜的晶化及导电聚合物膜层失效是导致有机钽电容器失效的主要因素,并提供了相应的解决方案,为高可靠性片式有机钽电容器的生产提供了技术支撑。     

钽电容器和独石电容器应用中的失效分析

通过对钽电容器和多层独石瓷介电容器的几个失效分析实例,得出以下结论：（1）钽电容器使用中常见的失效现象是焊接不当,导致内部焊锡流动引起短路失效,应引起起装机工作人员高度重视;（2）通过分立元器件的解剖方法结合详细的测试分析,找出独石瓷介电容器内部的质量问题在于介质中的缺陷,导致电极材料局部突起,以至发生离子迁移或短路失效。     

蒸汽被膜工艺试验

本文介绍固体钽电解电容器电解质(MnO_2)蒸汽被膜工艺。通过对被膜工艺的改进,从而保证MnO_2与介质Ta_2O_5的结合紧密,MnO_2层致密、均匀、电导率高,使固体钽电解电容器具有优良的电性能。     

无定形钽、铌氧化膜的剥离成功

<正> 由于固体钽电容器具有高可靠、长寿命、体积小等特点,被广泛应用于军事电子设备(如人造卫星,宇航)和海、地缆通信设备中。国外固体钽电容器的失效率低,可靠性最高可达9～10级。 钽电容器阳极氧化膜作为介质,其结构稳定性对电解电容器的性能有直接的影响,特别     

高压(160V)液体钽电容器电解质的研究

研究了电解质对高压液体钽电容器电性能的影响。通过对液体钽电容器的阳极界面和阴极界面处的电极过程的研究,结合实验发现,阴离子电子发射及电致伸缩作用引起的介质膜强度下降是导致闪火发生的根本原因。工作电解质体系中加入适当去极化剂有利于减小产品的损耗和漏电流。     

热处理对钽芯及钽电容器电性能的影响北大核心CSCD

在实际使用过程中,钽电容器常因电容量、损耗和漏电流发生漂移而失效。为了改善钽电容器的电性能稳定性,系统研究了在空气环境中热处理对形成后的钽芯及钽电容器电性能的影响。采用阳极氧化法在烧结后的钽块表面形成Ta_(2)O_(5)介质氧化膜,然后对阳极钽芯进行热处理。研究结果表明:热处理对钽芯的击穿电压和漏电流传导机理无明显影响;热处理后的钽芯表面Ta_(2)O_(5)介质氧化膜的微观形貌未发生明显变化;经过适当热处理且补形成后的阳极钽芯的漏电流及所制备的钽电容器电容量稳定性、损耗和漏电流均得到了明显改善;合适的热处理工艺为300℃/45~60 min。     

钽阳极氧化膜(Ta-Ta_2O_5)的热处理

<正> 近年来,国内对固体电解质烧结钽电容器的工艺研究开展得很活跃。对二氧化锰被覆工艺的探讨,有了新的突破;高比容钽粉正在推广使用,在研究降低漏电流方面也取得了一定进展。本文将分析钽阳极氧化膜的热处理对漏电流的影响。 可靠性实验已经证阴,固体钽电解电容器的主要失效模式是漏电流增大。其表现形式有两种:一是漏电流增大,在极短的时间     

电解质对液体钽电容器闪火电压影响的研究

研究了电解质对高压液体钽电容器电性能的影响。通过对液体钽电容 阳极界面处和阴极界面处的电极过程的研究，结合实验发现，阴离子电子发射及电致伸缩作用引起的Ta2O5介质膜强度下降是导致闪火发生的根本原因。该文研究了电解质中的负离子浓度及有机物的含量对液体钽电解电容器闪火电压的影响。     

Highly reliable MIS capacitors with plasma nitridation and doubled dielectric-constant tantalum pentoxide

We studied effective thinning of metal-insulator-semiconductor tantalum pentoxide capacitors experimentally for DRAM application. First, we investigated the dielectric constant of a tantalum pentoxide film deposited and crystallized on an oxidation-resistant thick silicon-nitride film. Dependence of electrically equivalent thickness on physical thickness of tantalum pentoxide revealed an increased dielectric constant of 60, whereas the films on a silicon-dioxide film had a dielectric constant of no more than 40. To apply this increased dielectric constant to DRAM capacitors, we applied novel plasma nitridation on the surface of polysilicon. The plasma-nitrided surface showed fair oxidation resistance up to 800/spl deg/C, at which a tantalum pentoxide film fully crystallizes. The temperature was 100/spl deg/C higher than that of a conventional treatment using rapid thermal nitridation (RTN). The improved oxidation resistance enabled the increased dielectric constant as well as suppression of silicon oxide between the film and polysilicon. Consequently, effective thinning by 10% was demonstrated even on rugged polysilicon without increase of leakage current. Time-dependent dielectric-breakdown measurements revealed that the tantalum pentoxide capacitors fabricated using plasma nitridation are expected to have a lifetime three orders of magnitude longer than that of those fabricated using RTN.     

Tera Tool [terahertz time-domain spectroscopy]

The terahertz differential time-domain spectroscopic method is applied to characterize the dielectric and optical properties of a variety of thin films at terahertz frequency. The results of several samples including silicon dioxide, parylene-n polymer film, tantalum oxide film, and protein thin layer samples were presented. The dielectric property of silicon dioxide thin film is well fitted to that of a bulk. The dielectric properties of parylene-n thin films show good agreement with the result measured by the goniometric terahertz time-domain spectroscopy. The dielectric and optical properties of the tantalum oxide show reasonable data with previously available data. Some properties in thin films are slightly different from the bulk materials. The origin of this discrepancy is considered due to fine grain formation, mechanical stresses, formation of interfacial layers, or rough interfaces during thin-film deposition process. The terahertz differential time-domain spectroscopy may be applied to the measurement of the dielectric and optical properties of thin films (nanometer to micrometer) of several materials, which cannot be done by any other method.     

Dielectric films for capacitor applications in electronic technology

In microelectronic applications, various approaches have been used to provide high capacitance thin film components. None of these has been widely accepted for reasons that are both technical and economic. Limited applications have been made of silicon and other simple oxides, e.g., of aluminum or tantalum, as dielectric media. Particularly in the area of microwave integrated circuits, requirements for high frequency, high specific capacitance, low to moderate loss, and integrability call for new thin film approaches. These requirements will only be met by using more complex compounds, possibly of ferroelectric materials. Aspects of material preparation, composition evaluation, and dielectric performance of thin film bismuth titanates are treated in a manner which should be of value in considering other complex dielectrics for similar use. Of particular technological importance is the use of thin silica barrier layers at the metal electrodes to permit achieving low dielectric loss.     

Atomic Layer Deposition in the Production of a Gate HkMG Stack Structure with a Minimum Topological Size of 32 nm

The plasma-enhanced atomic layer deposition (PEALD) of a High-K Dielectric and Metal Gate (HkMG) stack for MIS transistors, including the subgate HfO₂ (2–4 nm) dielectric layer, the ultrathin metallic stabilizing hafnium nitride HfN (1–3 nm) layer, and the basic metallic gate layer from tantalum nitride ТаN (10–20 nm), on silicon plates with a diameter of 200 mm is studied. The spectral ellipsometry method is applied to measure the homogeneity of the deposited film thickness. The dielectric constant of the dielectric in the stack, the leak current, and the breakdown voltage are examined. The four-probe method is used to study the specific electric resistance of tantalum nitride deposited by the atomic layer deposition ALD method. The film thickness homogeneity as a function of the ALD process parameters is examined. The specific resistance of the metallic TaN layer as a function of the composition and parameters of the plasma discharge are studied.     

CA30型非固体钽电解电容器的可靠性

改善 CA30型非固体钽电解电容器结构的密封性、介质氧化膜的质量及工作电解液温度特性是提高产品质量的稳定性、可靠性及使用寿命的三个关键因素。将半密封结构改为全密封结构 ,产品质量可显著提高。     

High Density Double and Triple Layer Tantalum Pentoxide Decoupling Capacitors

High-performance integrated circuits (ICs) require extremely low impedance power distribution. The low voltage, high current requirements of these devices must be provided by decoupling capacitors very close to the IC. Currently this decoupling is provided by discrete surface mount capacitors with relatively high parasitic inductance, requiring many devices in parallel to provide low impedance at high frequencies. Thin film, large area tantalum pentoxide (TaO) dielectric capacitors exhibit very low parasitic inductance, but have been limited in capacitance density to 100nF/cm for single layer devices. Multilayer thin film capacitors can substantially increase the available capacitance. These multilayer thin film capacitors can be fabricated in a variety of ways, allowing them to be embedded between FR-4 layers, under ICs, or even embedded in IC packages. We previously described the initial results of two-layer capacitors fabricated on silicon . These devices had two dielectric layers and three copper plates. Recently we extended the technology to three dielectric layers, and fabricated devices with dielectrics as thin as 1000, to yield a total capacitance density of 0.6F/cm. Capacitors were fabricated on silicon wafers by sputtering a metal plate topped with tantalum, and then wet anodizing the tantalum layer. The process was repeated to create a multilayer stack. The stack was then patterned from top to bottom by successive lithographic and etching steps. This paper will describe the fabrication process in detail. Detailed electrical properties for the resulting two and three layer devices, such as capacitance density, leakage current, breakdown voltage, and impedance will be presented. Using the three-layer process, we fabricated devices for inclusion in a 3-D electronic assembly for a DARPA program, and these devices will be described. Screening and test methods to ensure device reliability will be briefly discussed.     

A low voltage and small hysteresis C_(60) thin film transistor

Organic thin film transistors with C_(60) as an n-type semiconductor have been fabricated.A tantalum pentoxide(Ta_2O_5)/poly-methylmethacrylate(PMMA) double-layer structured gate dielectric was used.The Ta_2O_5 layer was prepared by using a simple solution-based and economical anodization technique.Our results demonstrate that double gate insulators can combine the advantage of Ta_2O_5 with high dielectric constant and polymer insulator for a better interface with the organic semiconductor.The performanc...     

ALD氧化铝薄膜介电性能及其在硅电容器的应用

硅基高密度电容器是利用半导体3D深硅槽技术和应用高介电常数(高K)材料制作的电容。相比钽电容和多层陶瓷电容(MLCC),硅基电容具有十年以上的寿命、工作温度范围大、容值温度系数小以及损耗低等优点。文章研究原子层沉积(ALD)制备的Al2O3薄膜的介电特性,通过优化ALD原子沉积温度和退火工艺,发现在沉积温度420℃和O3气氛退火5 min下,ALD生长的Al2O3薄膜击穿强度可大于0.7 V/nm,相对介电常数达8.7。制成的硅基电容器电容密度达到50 nF/mm2,漏电流小于5 nA/mm2。     

Thin RF sputtered and thermal Ta2O5 on Si for high density DRAM application

Tantalum pentoxide thin films on Si prepared by two conventional for modern microelectronics methods (RF sputtering of Ta in Ar + O₂ mixture and thermal oxidation of tantalum layer on Si) have been investigated with respect to their dielectric, structural and electric properties. It has been found that the formation of ultra thin SiO₂ film at the interface with Si, during fabrication implementing the methods used, is unavoidable as both, X-ray photoelectron spectroscopy and electrical measurements, have indicated. The initial films (as-deposited and as-grown) are not perfect and contain suboxides of tantalum and silicon which act as electrical active centers in the form of oxide charges and interface states. Conditions which guarantee obtaining high quality tantalum oxide with dielectric constant of 32–37 and leakage current density less than 10⁻⁷ A/cm² at 1.5 V applied voltage (Ta₂O₅ thickness equivalent to about 3.5 nm of SiO₂) have been established. These specifications make the layers obtained suitable alternative to SiO₂ for high density DRAM application.