Measurement of residual stress in a multi-layer semiconductor heterostructure by micro-Raman spectroscopy

Si-based multilayer structures are widely used in current microelectronics. During their preparation, some inhomogeneous residual stress is induced, resulting in competition between interface mismatching and surface energy and even leading to structure failure. This work presents a methodological study on the measurement of residual stress in a multi-layer semiconductor heterostructure. Scanning electron microscopy（SEM）, micro-Raman spectroscopy（MRS）, and transmission electron microscopy（TEM） were applied to measure the geometric parameters of the multilayer structure. The relationship between the Raman spectrum and the stress/strain on the [100] and [110] crystal orientations was determined to enable surface and crosssection residual stress analyses, respectively. Based on the Raman mapping results, the distribution of residual stress along the depth of the multi-layer heterostructure was successfully obtained.

中煤级煤Micro-Raman结构对甲烷吸附的响应

煤与甲烷、二氧化碳等流体作用后的体积膨胀及其机制一直是煤层气地质学和煤与瓦斯突出防治研究中的重要课题之一。以往的研究主要集中在宏观吸附膨胀及变形,并从力学的角度解释其膨胀机制。实际上,煤作为由大分子构成的分子体系,与甲烷、二氧化碳的相互作用是一种分子现象,其膨胀变形的本质应该是分子体系发生了变化,因此揭示煤大分子结构对煤体吸附膨胀的响应特征是认识其机制的基础。应用显微-拉曼光谱法对吸附甲烷前后的8个中煤级煤样(镜质组最大反射率R_(o)=1.08%~1.80%)进行了结构表征,并运用Origin 8.5软件对煤样吸附甲烷前后的拉曼光谱曲线进行了分峰拟合,在此基础上计算了煤样吸附前后的拉曼光谱结构参数。结果表明:原煤和吸附煤的G峰与D峰的峰位差d(G-D)随着煤级的增加有增大趋势,G峰半峰宽(FWHM-G)呈减小趋势,表明在反射率1.08%~1.80%阶段,煤结构有序度和微晶尺寸随煤级增加而逐渐增加;大芳香环(≥6)的相对含量(A_(D)/A_(G))出现先增加后减小的趋势,这是以较大芳香环的生成为主转为向石墨结构生成为主的结果;随着煤级增加,原煤的大芳香环结构中“杂质”(A_(S)/A_(D))及氢化芳环上的C—C的含量(A_(S)/A_(total))均有减小的趋势,反映出煤结构中sp^(2)-sp^(3)杂化烷基碳或氢化芳环逐渐减少,有序度逐渐增加;当R_(o)>1.3%时,吸附煤相对原煤的d(G-D)及A_(D)/A_(G)减少,小芳香环相对含量(A_(GR+VR+VL)/A_(D)),A_(S)/A_(D),A_(S)/A_(total)和FWHM-G增加,表明甲烷吸附变形引起环数较大的芳香环和微晶结构破裂形成较小的芳香环。这一结果对于认识煤大分子结构与甲烷的相互作用机制提供了理论依据。

Development of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus

We developed a set of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus because of the scientific significance of in-situ Micro-Raman spectroscopy system under the high-pressure hydrothermal condition.We used this system to measure the Raman spectrum of water-fluid and quartz crystal at the temperature ranging from 125 to 420℃.The signal-tonoise ratio of the Raman signal is good.

Comparison between Double Crystals X-ray Diffraction and Micro-Raman Measurement on Composition Determination of High Ge Content Si_(1-x)Ge_(x) Layer Epitaxied on Si Substrate

It is important to acquire the composition of Si1-xGex layer, especially that with high Ge content, epitaxied on Si substrate. Two nondestructive examination methods, double crystals X-ray diffraction （DCXRD） and micro-Raman measurement, were introduced comparatively to determine x value in Si1-xGex layer, which show that while the two methods are consistent with each other when x is low, the results obtained from double crystals X-ray diffraction are not credible due to the large strain relaxation occurring in Si1-xGex layers when Ge content is higher than about 20%. Micro-Raman measurement is more appropriate for determining high Ge content than DCXRD.

Low-energy(40 keV) proton irradiation of YBa_2Cu_3O_(7-x) thin films:Micro-Raman characterization and electrical transport properties

To investigate the damage profiles of high-fluence low-energy proton irradiation on superconducting materials and related devices, Raman characterization and electrical transport measurement of 40-keV-proton irradiated YBa_2Cu_3O_(7-x)(YBCO) thin films are carried out. From micro-Raman spectroscopy and x-ray diffraction studies, the main component of proton-radiation-induced defects is found to be the partial transition of superconducting orthorhombic phase to the semiconducting tetragonal phase and non-superconducting secondary phase. The results indicate that the defects induced in the conducting CuO_2 planes, such as increased oxygen vacancies and interstitials, can result in an increase in the resistivity but a decrease in the transition temperature TCwith the increase in the fluence of proton irradiation, which is confirmed in the electrical transport measurements. Especially, zero-resistance temperature TC_0 is not observed at a fluence of 10^(15)p/cm^2.Furthermore, the variation of activation energy U_0 can be explained by the plastic-flux creep theory, which indicates that the plastic deformation and entanglement of vortices in a weakly pinned vortex liquid are caused by disorders of point-like defects. Point-like disorders are demonstrated to be the main contribution to the low-energy proton radiation damage in YBCO thin films. These disorders are likely to cause flux creep by thermally assisted flux flow, which may increase noise and reduce the precision of superconducting devices.

Study of Thermal Conductivity of Porous Silicon Using the Micro-Raman Method

In this work, we are interesting in the measurement of thermal conductivity (on the surface and in-depth) of Porous silicon by the micro-Raman spectroscopy. This direct method (micro-Raman spectroscopy) enabled us to develop a systematic means of investigation of the morphology and the thermal conductivity of Porous silicon oxidized or no. The thermal conductivity is studied according to the parameters of anodization and fraction of silicon oxidized. Thermal transport in the porous silicon layers is limited by its porous nature and the blocking of transport in the silicon skeleton what supports its use in the thermal sensors.

A polarized micro-Raman study of a 0.65PbMg_(1/3)Nb_(2/3)O_3-0.35PbTiO_3 single crystal

Polarized micro-Raman spectra of a 0.65PbMgl/3Nb2/303 0.35PbTiO3 （0.65PMN-0.35PT） single crystal poled in the [001] direction are obtained in a wide frequency range （50 2000 cm^-1） at different temperatures. The best fit to the Raman spectrum at 77 K is achieved using 17 Lorenzians to convolute into it, and this is proved to be a reasonable fit. According to the group theory and selection rules of overtone and combinational modes, apart from the seven Raman modes that are from first-order Raman scattering, the remaining ones are attributed to being from second-order Raman scattering. A comparison between the experimental results and theoretical predictions shows that they are in satisfactory agreement with each other. Our results indicate that at 77 K the sample belongs to the rhombohedral symmetry with the C^53v（R3m） space group （Z = 1）. In our study, on heating, the 0.65PMN 0.35PT single crystal undergoes a rhombohedral → tetragonal → cubic phase transition sequence. The two phase transitions occur at 340 and 440 K, which correspond to the disappearance of the soft mode near 106 cm-1 recorded in VV polarization and the vanishing of the band around 780 cm^-1 in VH polarization, respectively.

Micro-Raman and SEM Analysis of Minerals from the Darhib Mine, Egypt

The Darhib mine is one of the several talc deposits in the Hamata area of southeastern Egypt. Several specimens of minerals coming from this mine were subjected to complementary investigation by micro-Raman spectrometry and scanning electron microscopy. The difficulty in their identification is the appearance of most of them: they are all very small and only visible under the mineral binocular microscope(×10 - ×40). They appear as small crystals in fissures and holes and a visual determination on colour and crystal gives only a guess of what kind of mineral it could be. Therefore, only after analyzing them by micro-Raman and scanning electron microscopy it was possible to identify their structure and they can be divided in three main groups: one is quite generic and several minerals of different species were identified, such as quartz, talc, mottramite and chrysocolla, very common in the talc mine (these ones are Si-based minerals);the other one is constituted by four samples which are Zn and/or Cu rich, which means minerals of the rosasite or aurichalcite groups;the last group is constituted by two samples containing mainly Pb..

不同产地楮实子及伪品的近红外漫反射指纹图谱聚类分析

目的:对不同产地楮实子及其伪品进行指纹图谱鉴定分析。方法:用近红外漫反射光谱技术及聚类分析方法对楮实子药材及其伪品进行分析。结果:不同产地楮实子之间指纹图谱存在一定差异,与伪品差异较大。结论:该方法可用于楮实子药材的指纹图谱鉴定,快速方便。不同产地楮实子之间的差异与药材性状有一定关联。

脂肪酰胺类缓蚀剂对X65钢抗CO_2腐蚀的机理研究

通过电化学极化及电化学阻抗谱(EIS)测试研究了一种脂肪酰胺类缓蚀剂对X65低碳钢抗CO2腐蚀的机理,结果表明,该类缓蚀剂是一种阳极型缓蚀剂,属于界面吸附型,通过负催化机制产生缓蚀作用,对X65低碳钢抗CO2腐蚀具有良好的效果,其缓蚀效率随浓度的增加而提高,存在极值现象,在0．5 g／L时达到最大．其阻抗谱有2个时间常数,相应的等效电路的描述码(CDC)为:R(C(R(CR)))．

显微拉曼光谱对几种宝石矿物的无损鉴定

依据矿物的拉曼光谱前四强特征峰确定矿物的主要成分,同时特征峰的峰型、线宽,以及荧光峰可以作为宝石矿物鉴定的辅助信息。本文介绍几件宝石无损鉴定检测实践。

稻草木素生物降解的研究

介绍了我们最近对稻草木素生物降解研究进展。通过诱变选育分离出高降解木素的优良菌株,10天内脱木素率高达59%,明显地缩短了生物作用周期;利用电子显微镜技术,详细揭示白腐菌生物降解草类植物的微观过程和稻草组织内部以及纤维细胞壁的微观结构的变化,同时,发现所选育的菌种具有:(1)优先降解纤维胞间层,致使纤维能保持完整地分离;(2)没有发生纤维细胞壁变薄破坏的现象;(3)生物作用初期就能分解除去不利于造纸的薄壁细胞;(4)能选择性降解纤维次生壁上的木素,微细纤维结构不被破坏而裸露出来等非常可贵的优良特性。这些特性十分有利于生物制浆造纸。系统分析和研究了生物脱木素过程及一些重要生理条件对脱木素的影响规律。发现生物脱木素过程可分为三个阶段。不同阶段生理条件对脱木素的影响不同。通氧培养、添加营养氮源或碳源及控制底物的湿含量能促进生物脱木素作用。为了解稻草木素生物降解规律,利用核磁共振技术定量及定性分析比较生物作用前后木素的结构特征。结果表明木素大分子的生物降解主要是氧化反应,在菌的作用下,木素结构中 C_γ被氧化、C_α—C_β键、C_β—C_γ,键以及芳香环被氧化断裂。其降解顺序为:以酯键连结的对香豆酸为主体的对羟苯基单元,愈疮木基单元和紫丁香基单元。菌优先作用于纤维细胞间层的结论与电子显微镜观察结果一致。上述特征和规律显示白腐菌 P.conchatus 对发展草类生物制浆及其他脱木素工艺均具有巨大潜在应用优势。

FT-IR、UV/VIS、Raman光谱法研究血红蛋白和银、铜离子的作用

本文报导血红蛋白（Hb）同银（Ⅰ）-铜（Ⅱ）离子的作用．研究表明，在pH10．5的B5O72--OH-缓冲介质中，当有十二烷基硫酸钠（SDS）和甲醛存在时，Hb－Ag-Cu物种表现出强的橙黄色，用FT-IR、UV／VIS和振动Raman光谱研究了Hb-Ag-Cu物种的形成机理．表明血红蛋白中氨基酸残基上的氮和氧与银-铜离子有较强的作用，对Hb中氨基的修饰证明了这一机理。

代谢综合征患者脑磁共振波谱及弥散张量成像研究

目的应用磁共振波谱(Magnetic Resonance Spectrum,MRS)及磁共振弥散张量成像(Diffusion Ten sor Imaging,DTI)检测代谢综合征(metabolic syndrome,MS)患者的脑内代谢物、脑部各向异性(fractional anisotro py,FA)值,早期发现亚临床脑细胞损害。方法选取病程5年以上、无神经系统损害临床表现的MS患者15例为患者组,及健康体检者17名为对照组,检查一般项目(身高、体重、血压、血糖、血脂、神经功能相关量表评分),并行头颅MRI、DWI、MRS和DTI检查,测定脑部背侧丘脑、扣带回后部、侧脑室后角NAA/Cr、Cho/Cr、NAA/Cho的比值及内囊后肢、放射冠区FA值,所测得结果在患者组和对照组,以及患者组中3项代谢异常者与对照组、患者组中2项代谢异常者与对照组间进行比较。结果患者组、患者组中3项代谢异常者、患者组中2项代谢异常者NAA/Cr、NAA/Cho在背侧丘脑、扣带回后部、侧脑室后角均低于对照组,差异有统计学意义(均P<0.05),Cho/Cr在扣带回后部、侧脑室后角高于对照组,差异有统计学意义(均P<0.05)。患者组双侧内囊后肢、右放射冠区FA值均低于对照组(均P﹤0.05);患者组3项代谢异常者双侧内囊后肢及右放射冠区较对照组降低(均P﹤0.05);患者组2项代谢异常者仅右侧放射冠区较对照组降低(P﹤0.05)。结论病程5年以上的MS患者在背侧丘脑、扣带回后部、侧脑室后角的脑细胞代谢及在内囊后肢、放射冠区的神经纤维微结构已有损害。

电子能谱仪多通道信号系统升级改造

一种电子能谱仪多通道数据收集系统升级方案。在SSA(球扇型能量分析器)出口处以多通道板或多只电子倍增器代替单只倍增器,信号经过多路前置放大器后进入电脑,经移位合成后输出所需谱图,其灵敏度为原信号的多倍且分辨率有所提高。

基于气体吸收理论的激光光谱气体在线监测技术研究

气体对激光能量的吸收是一种比较普遍的吸收现象,本文利用可调谐半导体激光吸收光谱技术,依据大学物理光学部分的比尔-朗伯尔定律为依据,通过气体吸收实验验证了气体的基本吸收理论,获得了760.77nm吸收波长处不同氧气浓度情况下的基本吸收谱线幅值,得出了气体浓度越高,对光的吸收也越强的结论.并进一步对实验数据进行曲线拟合,使学生深入理解曲线拟合方法在气体浓度监测方面的应用.通过本实验可以增加学生的视野和对新技术的了解,以及对气体吸收理论的进一步理解.

激光Raman光谱研究2,4己二炔-1,6二醇的双苯异氰酸酯的聚合——晶型对固相聚合活性的影响

用激光Raman光谱研究了三种不同晶型的2,4-已二炔-1,6二醇的双苯异氰酸酯(HDPU)的聚合,发现不同晶型的HDPU的聚合活性与其C=C伸缩振动频率的频移之间存在内在联系。这说明单体晶格与聚合物晶格的匹配是HDPU具有高的聚合活性的必要条件。

Evaluation of self-healing properties of inhibitor loaded nanoclay-based anticorrosive coatings on magnesium alloy AZ91D

This study emphasizes on the evaluation and comparison of the anticorrosive properties of sol-gel coatings with and without inhibitor loaded nanocontainers.In this case,naturally available clay nanotubes(halloysite)were loaded with cationic corrosion inhibitors Ce 3+/Zr 4+.These nanocontainers were dispersed in hybrid organic-inorganic sol-gel matrix sol.Coating was applied on magnesium alloy AZ91D using the sols containing modified and unmodified nanocontainers employing the dip coating method and cured at 130℃for 1 h in air.Corrosion resistance of coated/uncoated substrates were analyzed using electrochemical impedance spectroscopy,potentiodynamic polarization and weight loss measurements after exposure to 3.5 wt%NaCl solution for varying time durations between 24 h to 120 h.Self-healing ability of coatings was evaluated by micro-Raman spectroscopy after 120 h exposure to 3.5 wt%NaCl solution.Coatings generated after dispersion of corrosion inhibitor loaded clay in hybrid sol-gel matrix have shown more promising corrosion resistance when compared to just the sol-gel matrix coatings,after prolonged exposure to corrosive environment.

Experimental Investigation of Polycrystalline Material Deformation Based on a Grain Scale

We propose an experimental approach for investigation of the polycrystalline deformation behaviour at a grain scale. The technique is characterized by the joint application of micro material testing systems and the intragranular deformation analysis methods, It is attempting to map the deformation evolution at grain scale during the elastic and plastic deformations of polycrystalline specimens.

Residual stress evolution regularity in thermal barrier coatings under thermal shock loading

Residual stress evolution regularity in thermal barrier ceramic coatings （TBCs） under different cycles of thermal shock loading of 1 100℃ was investi- gated by the microscopic digital image correlation （DIC） and micro-Raman spec- troscopy, respectively. The obtained results showed that, as the cycle number of the thermal shock loading increases, the evolution of the residual stress under- goes three distinct stages： a sharp increase, a gradual change, and a reduction. The extension stress near the TBC surface is fast transformed to compressive one through just one thermal cycle. After different thermal shock cycles with peak temperature of 1 100℃, phase transformation in TBC does not happen, whereas the generation, development, evolution of the thermally grown oxide （TGO） layer and micro-cracks are the main reasons causing the evolution regularity of the residual stress.