PI/AIN纳米复合薄膜结构与介电性能研究

采用原位聚合法制备了聚酰亚胺/氮化铝(PI/AlN)纳米复合薄膜,用小角散射(SAXS)、扫描电镜(SEM)对薄膜进行表征,研究了不同纳米掺杂量对材料电阻率、介电常数(ε)和介质损耗因数(tanδ)的影响.结果表明,随着纳米AlN含量的增加,分形结构由质量分形转变为表面分形,当AlN含量为1％时,复合薄膜的介电常数达到最低值,电阻率提高了一个数量级；介质损耗在低频范围内明显增加；AlN的掺杂提高了纳米复合薄膜的绝缘性能.     

聚全氟乙丙烯/氮化铝高导热绝缘复合材料的研究

采用聚全氟乙丙烯(FEP)为基体,偶联处理的氮化铝(AlN)为填料,通过共混、模压等方法制备了高导热、高绝缘的FEP/AlN复合材料。结合材料导热计算模型,分析了AlN含量对材料热导率、体积电阻率、力学以及流变性能的影响。结果表明:随AlN填充量的增加,复合材料的热导率呈近线性增加,当填加AlN的质量百分率为30%时,材料的热导率可达2.22 W/(m.K),体积电阻率可达1.5×1013Ω.m,并具有较好的力学性能和流变性能。     

无色透明聚酰亚胺-二氧化硅纳米复合薄膜的制备与性能

采用1S,2R,4S,5R-氢化均苯四甲酸二酐(H-PMDA)与含氟芳香族二胺2,2′-双(三氟甲基)联苯二胺(TFMB)通过一步高温溶液缩聚法制备了TFCPI半脂环族聚酰亚胺树脂及相应的无色透明聚酰亚胺薄膜TFCPI-0。采用TFCPI树脂基体，通过机械共混法与胶体纳米二氧化硅(SiO₂)/N,N-二甲基乙酰胺(DMAC)分散液进行复合，制备了一系列不同SiO₂含量的无色透明聚酰亚胺复合薄膜。结果表明：当纳米SiO₂在复合薄膜中的质量分数为25%时，制备的TFCPI-25复合薄膜在450 nm波长处的透光率(T₄₅₀)与黄度指数(b^*)分别为87.8%与1.56，较TFCPI-0薄膜仅略有下降(T₄₅₀=88.5%,b^*=0.91)。TFCPI-25复合薄膜在氮气中的5%失重温度(T_5%)和玻璃化转变温度(T_g)与TFCPI-0薄膜处于同一水平。但TFCPI-25复合薄膜在50℃时的储能模...     

改性3-氨丙基三甲氧基硅烷对聚酰亚胺/二氧化硅复合薄膜性能的影响

用正硅酸乙酯(TEOS)和改性3-氨丙基三甲氧基硅烷(APTMOS)作为无机前驱体,采用溶胶-凝胶法制备了聚酰亚胺/二氧化硅(PI/SiO2)复合薄膜.采用傅立叶变换红外光谱(FT-IR),扫描电子显微镜(SEM)和热重分析(TGA)对PI/SiO2纳米复合薄膜进行了表征,讨论了改性APTMOS的加入对PI/SiO2复合薄膜结构和耐电晕性能的影响.结果表明,改性APTMOS的加入明显降低了SiOO2粒子的团聚,并提高了PI/SiO2纳米复合薄膜的耐电晕性能.     

SiO2空心球-GO复合物提高聚酰亚胺复合薄膜的介电及力学性能

采用改进的Hummers法制备氧化石墨烯（GO）,以γ-缩水甘油醚氧丙基三甲氧基硅烷（KH560）为改性剂制得改性GO(mGO)。采用改进的St?ber法制备二氧化硅空心球（SHS）,以3-氨基丙基三乙氧基硅烷（APTES）为改性剂制得改性SHS(mSHS)。将mGO和mSHS复合制备mSHS-mGO复合物,再以4,4′-二胺基二苯醚（ODA）和均苯四甲酸二酐（PMDA）为单体,采用原位聚合法制备mSHS-mGO/聚酰亚胺（PI）复合薄膜,研究mSHS-mGO复合物对PI薄膜力学和介电性能的影响。结果表明：5%mSHS-0.3%mGO/PI复合薄膜的介电常数为2.26(105Hz),相比于纯PI薄膜（3.04,105Hz）降低了26%。3%mSHS-0.3%mGO/PI复合薄膜的拉伸强度和断裂伸长率为86.92 MPa和13.87%,分别比纯PI薄膜（79.00 MPa和9.00%）提高了10%和54%。     

聚酰亚胺/导电炭黑抗静电复合薄膜的性能研究

采用原位聚合法制备了聚酰亚胺/导电炭黑(PI/ECB)抗静电复合薄膜,并探讨了复合薄膜的结构、微观形貌以及导电炭黑用量对其表面电阻率、热性能和力学性能的影响。结果表明:复合薄膜亚胺化完全,热性能得到提高;炭黑的质量分数为4%时,复合薄膜表面电阻率的数量级为108,达到抗静电的最佳要求。     

嵌入式电容用钛酸钡/聚酰亚胺复合薄膜的制备及性能研究

对钛酸钡(BT)纳米粒子进行了表面改性,采用原位聚合法将钛酸钡与聚酰亚胺复合制备了高介电BT/PI复合薄膜,为了进一步提高介电性能,将第三组分炭黑掺入其中,并对其进行了红外光谱、扫描电镜(SEM)分析和介电性能测试。结果表明:与未改性的复合薄膜相比,改性后纳米粒子在基体中分散更加均匀,复合薄膜的介电性能明显提高,可用于制备嵌入式电容中的电介质材料。     

GO/PI复合薄膜的制备及性能研究

利用改进Hummers法制备氧化石墨烯(GO),再通过溶液共混法制备氧化石墨烯/聚酰亚胺(GO/PI)复合薄膜,采用XRD、TMA、TGA等对其结构和性能进行表征.结果表明:相对于不添加GO的PI薄膜而言,当复合薄膜中的GO质量分数为0.2％时,复合薄膜的力学性能得到很大提升,其中拉伸强度提高了26.77％,断裂伸长率提高了76.47％,弹性模量基本不变.当GO质量分数为0.1％时,复合薄膜的T5、T10最大值分别为587.3℃、603.3℃,相对于未添加GO的PI薄膜分别提高了2.44％、1.69％.说明适量GO的加入可以显著增强复合薄膜的力学性能和热学性能.     

FeCoAlN软磁薄膜的制备与性能

采用磁控溅射法在Ar+N2的混合气氛中制备FeCoAlN薄膜,并对其进行磁场真空热处理,以研究薄膜的结构、磁性及热稳定性。当N2与(N2+Ar)的流量比为9%时制备的薄膜具有良好的软磁性能。随着Al含量的增加,薄膜的热稳定性明显得到改善。Al含量为13.5%的(Fe64.8Co35.2)AlN薄膜在400℃真空磁场热处理60min,仍然具有良好的软磁性能,其饱和磁化强度μ0Ms为1.2T,易轴矫顽力为0.68kA/m,各向异性场为2.8 kA/m。     

导电片状镍粉/聚酰亚胺复合薄膜的制备与性能研究

采用原位聚合法合成了导电片状镍粉/聚酰胺(CFNP/PAA)溶液,通过热亚胺化制备了CFNP/PI复合薄膜,对复合薄膜的红外光谱、热性能、力学性能、电性能、表面形貌进行了分析。结果表明:CFNP的加入不影响复合薄膜的亚胺化,随着CFNP含量的增加,CFNP/PI复合薄膜的电气强度和体积电阻率下降,导电能力明显提高,热稳定性提高,力学性能有所下降。当CFNP质量分数为21.5%时,复合薄膜的体积电阻率下降至85Ω·m,达到渗流阈值。     

Mechanics of thin films and microdevices

This paper discusses the latest developments in nanomechanics of thin films with applications in microelectromechanical systems (MEMS) and microelectronics. A precise methodology that combines in situ atomic force microscopy (AFM) surface measurements of uniaxially tension-loaded MEMS specimens and strain analysis via digital image correlation (DIC) achieving 0.1 pixel spatial displacement resolution is presented. By this method, the mechanical deformation of thin films was obtained in areas as small as 4 /spl times/ 4 /spl mu/m and with 1-2 nm spatial displacement resolution supporting the derivation of interrelations between the material microstructure and the local mechanical properties. This methodology provided for the first time the values of Young's modulus and Poisson's ratio from specimens with cross-sections as small as 2 /spl times/ 6 /spl mu/m. The value of properties derived via AFM/DIC demonstrated very limited scatter compared to indirect mechanical property measurement methods. The application of this technique on nonuniform geometries resolved nanoscale displacement and strain fields in the vicinity of ultrasharp elliptical perforations achieving very good agreement with finite element models. Furthermore, the stochastic and deterministic material failure properties described via Weibull statistics and fracture toughness, respectively, are illustrated for brittle thin films. Failure initiated at notches was found to be influenced by the local radius of curvature and the stress concentration factor. Precise fracture toughness values for MEMS materials were obtained from MEMS specimens with atomically sharp cracks. These studies were supported by measurements of displacements/strains conducted for the first time in the vicinity of mathematically sharp cracks via the AFM/DIC method. The method can be applied to a variety of thermomechanical reliability problems in multilayered thin films and inhomogeneous/anisotropic materials.     

Drying temperature effects on the electro-optic coefficients of PZT thin films

Abstract

PZT thin films were fabricated on ITO/glass substrates using sol-gel method. The main processing variable was the drying temperature: 300, 350, 450 and 500°C. The microstructure and electric properties (polarization and dielectric constant) were investigated. The electric properties were dependent on the perovskite phase content and the grain size affected by the nucleation of perovskite phase. The two-beams polarization interferometer was used for the measurement of electro-optic coefficients of PZT thin films, and these values were analyzed by comparing the electric properties.     

蒙脱土/聚酰亚胺复合薄膜的电击穿破坏特性

通过在聚酰亚胺基体中引入一定量MMT片层,可以改善薄膜的耐电老化性能,对薄膜电老化前后表面形貌及化学组成的研究结果表明:MMT片层均匀而充分的分散提高了MMT/PI薄膜的耐电弧性,这是聚酰亚胺薄膜电老化性能改善的原因。     

Mechanical and electric fatigue of PZT(53/47) films on metallic substrates

Abstract

We have investigated the fatigue of electromechanical and dielectric properties of sol-gel derived PZT(53/47) thin films deposited on metallic substrates by means of electric and mechanical cycling. For the mechanical cycling a two point bending method was used to apply transversal stress to the samples. During mechanical cycling the piezoelectric coefficient d₃₁ remained constant up to about 10⁵ cycles, for a higher number of cycles a strong decrease was observed. During electric cycling no significant changes in the ferroelectric and electromechanical hysteresis loops could be found up to about 3×10⁵ cycles. Above this number the coercive field increases, the maximum strain and the remanent polarization decrease.

Obviously each electric cycling of the investigated films is accompanied by a mechanical cycling. It is assumed, that microcracks induced by mechanical stress are the main reason for the deterioration of the physical properties films during electric and mechanical cycling both.     

Excess Bismuth-Dependent Characteristics of Chemical Solution Deposited Bi3.15La0.85Ti3O12 Thin Films

The phase formation and electrical properties of (Bi_3.15La_0.85)Ti₃O₁₂ (BLT) thin films prepared by the chemical solution deposition method on Pt/Ti/SiO₂/Si substrates have been investigated. It was observed that the microstructure and electrical properties of BLT thin films dramatically varied with the excess Bi content. The crystallographic orientation of BLT films was varied with excess Bi content and the intermediate rapid thermal annealing (RTA) process. While BLT thin films prepared without intermediate RTA process have ?117? orientation irrespective of excess Bi content, BLT thin films with RTA process at 450°C have an orientation change with excess Bi content. The leakage current of BLT thin films slightly increased with increasing excess Bi content up to 6.5% and then considerably decreased in BLT film with 10% Bi, where was revealed to be almost stoichiometric composition.     

Optical and photoluminescence properties of Ga doped ZnO nanostructures by sol-gel method

Zinc oxide (ZnO) nanocrystallites with different Ga-doping levels were successfully prepared by spin coating sol?Cgel technique. The morphological properties of Ga doped ZnO films were studied by atomic force microscopy (AFM). Alignment of ZnO nanorods with respect to the substrate depends on the amount of Ga dopant content. The dopant content varies from 1?% to 4?%, based on Ga-doping levels. The optical properties of the ZnO nanocrystallites following Ga-doping were also investigated by UV?CVisible absorption and Photoluminescence spectra. Our results indicate that Ga-doping can change the energy-band structure and effectively adjust the intensity of the luminescence properties of ZnO nanocrystallites. Transmittance spectra of the films indicate that the films have high transparency. The refractive index dispersion was analyzed by single oscillator model developed by Wemple and DiDomenico. The oscillator energy, dispersion energy, high frequency dielectric constant values for the films were determined were calculated and it is found that the optical parameters are changed with Ga-doping content.     

Preparation of PLZT Ferroelectric Films by RF Sputtering on 200 mmφ Substrate

(Pb, La)(Zr, Ti) O 3 (PLZT) thin films were deposited on 200mm } Pt/Ti/SiO2/Si substrates by RF magnetron Sputtering using multichamber production system. The Pb content in PLZT films deposited at low temperature was measured by X-ray fluorescence spectroscopy (XRF), and ferroelectrics properties were measured. Good uniformities of Pb content and deposition rate were achieved on 200mm } substrate. For ferroelectrics properties, only small deference was observed between the center and the edge of 200mm } substrate.     

Phase Formations and Electrical Properties of Various (Bi, La)4Ti3O12 Thin Films by Chemical Solution Deposition

The phase formation and electrical properties of (Bi, La)₄Ti₃O₁₂ (BLT) thin film and V-, Sm-doped BLT thin films prepared by the chemical solution deposition method on Pt/TiO₂/SiO₂/Si substrates have been investigated. It was observed that the microstructure and electrical properties of BLT thin films dramatically varied with V- and Sm-doping. The crystallinity and grain size of BLT thin films were definitely increased by V- and Sm-doping into BLT films, which resulted in the enhancement of remanent polarization in doped BLT films. The remanent polarization (Pr) of Sm-doped BLT films annealed for 3 min by an RTA system was about 9 C/cm². The V- and Sm-doped BLT films also exhibited good fatigue characteristics under bipolar stressing to 10¹⁰ cycles.     

NiZn铁氧体靶材及薄膜的磁性能和微观结构

首先采用固相反应法制备NixZn1-xFe2O4铁氧体靶材(x=0.2～0.8),研究了Ni取代量对靶材性能的影响;并选用Ni0.5Zn0.5Fe2O4靶材,采用射频磁控溅射法在Si(100)基片上制备了NiZn铁氧体薄膜.靶材样品的分析结果表明,随Ni含量增加,样品的X射线衍射峰向高角方向移动,晶格常数和平均晶粒尺寸都单调减小;当x=0.5～0.6时,NixZn1-xFe2O4铁氧体饱和磁感应强度Bs较高,矫顽力Hc较小.薄膜样品的分析结果表明,制备的薄膜经800℃退火后,呈尖晶石结构,并沿(400)方向择尤取向;薄膜的饱和磁化强度Ms和面内矫顽力Hc分别为310kA/m和8.833kA/m.     

Depth-resolved correlation between physical and electrical properties of stressed SiNx gate insulator films

The physical and electrical properties of SiN_x gate insulator films with compressive and tensile internal stress have been investigated using various characterization techniques. The mechanical hardness measured by nano-indenter system showed the different distribution in the film depth direction according to the type of film stress. The uniformity of optical property inside films had a correspondence to the mechanical properties of stressed SiN_x films, as well. The contents and bonding states of hydrogen influenced the mechanical and optical properties of stressed SiN_x films. The leakage characteristics of tensile SiN_x films with uniform physical properties exhibited the lower current density than the compressive films with ~10^?7 A/cm² until 8 MV/cm. The correlation between physical and electrical properties depending on the internal stress will suggest the appropriate optimization of SiN_x gate insulator films to enhance the device performance and reliability.