热处理对硅片抗弯强度的影响

研究了热处理温度、时间及降温方式对不同氧、氮含量的氩气氛直拉硅（ＡＣＺ）及氮气氛直拉硅（ＮＣＺ）抗弯强度（σ）的影响规律。结果表明：硅氧络合物和氮硅氧络合物的生成使抗弯强度提高，沉淀的形成使强度下降。提出了既能消除热施主、又可避免强度降低的６５０℃热处理两段冷新工艺     

凝聚和离散——制备纳米材料的两大思路

纳米材料制备是当前材料领域研究的热点。本文从分析人：亡最早获得的纳米级TiO2的制备方法开始，进而综观迄今为止已经被证明属于成功的制备方法的特点，结合制备技术原理，讨论当前众多的纳米材料制备的思路，认为制备方法可以从不同大小粒子的相互运动和作用归结为凝聚和离散两类，即两大思路，两大思路不仅在过去为发明这一新型材料提供了设计思路，也将成为下一步纳米材料开发的主流设计途径。     

高温高压下金刚石/碳化硅体系烧结反应机理研究

本文研究了微米级金刚石与硅粉在高温(800~1 200℃)高压(5.1 GPa)下的反应机理。通过对金刚石与硅粉反应过程的研究,发现微米级金刚石与硅粉在硅熔点以下发生了反应;并指出高温高压下微米金刚石与硅粉的反应分为两个阶段:硅未熔化前的金刚石与硅的反应,硅熔化后的金刚石与硅、石墨与硅的反应。最后提出了一种新的合成金刚石/碳化硅复合材料的工艺,即采用高压熔渗法合成金刚石/碳化硅复合材料时,在温度略高于硅熔点之后保温一段时间,再升温到合成材料的设定温度,可以合成出结构更加均匀的、高质量的金刚石/碳化硅复合材料。     

高性能高硅铝基合金研究展望

目前国内外对于高性能铝硅合金的两大研究方向,一是低硅铝合金（si≤1％）,尽量降低Al—Si基体合金中杂质含量,最大限度提高合金导电性能;二是高硅铝合金（Si≥30％）,尽可能提高硅在铝合金中的过饱和度,此类高性能铝合金侧重提高材料的电热稳定性、耐摩擦性等力学性能。本文总结了国内外对于高硅铝合金的研究进展,提出通过添加稀土元素优化合金成分和采用先进制备技术等方法,以期获得高性能硅铝合金。     

基于硅靶和碳化硅靶的碳化硅薄膜磁控溅射工艺对比

目的 通过基于碳化硅陶瓷靶的直接溅射和基于硅靶与甲烷的反应溅射,在Si(100)基底上沉积碳化硅薄膜,对比两种工艺制备碳化硅薄膜的异同.方法 采用直接磁控溅射与反应磁控溅射工艺制备碳化硅薄膜,通过白光干涉仪、轮廓仪、X光电子能谱仪(XPS)分析薄膜粗糙度、厚度、沉积速率、组分,通过X射线衍射仪和扫描电子显微镜分析薄膜的物相结构和形貌.结果 基于硅靶和甲烷的反应溅射工艺,甲烷流量百分比为20％～70％时,沉积速率从11.3 nm/min升高到36.5 nm/min.甲烷流量百分比为20％～60％时,表面粗糙度Rq值变化不大;甲烷流量百分比为70％时,Rq值有增大的趋势.对于甲烷反应溅射工艺,硅碳元素比例可调,但甲烷气体不易控制.基于碳化硅陶瓷靶工艺,随沉积时间(即膜层沉积厚度)的增加,表面粗糙度Rq变化不大,硅碳原子比接近1:1.两种工艺制备的薄膜均为晶态,且为8H-SiC.结论 比较两种工艺,相同靶功率下,硅靶反应溅射的沉积速率明显快于碳化硅陶瓷靶.硅靶反应溅射的元素比例可调,但甲烷气体不易控制;碳化硅陶瓷靶的沉积过程稳定,硅碳原子比接近1:1.     

日本高磁感取向硅钢最新进展(Ⅱ)

收集整理日本2004年度硅钢专利文献152项，其中高磁感Hi—B取向硅钢专利文献34项。Hi—B钢最新技术涉及诸多方面，本文对开发高温退火隔离剂，改善最终高温退火工艺，无铬薄膜的形成方法，改善薄膜质量进行了分析、研究，以供借鉴。     

IN SITU TEM OBSERVATION OF NANOSILICON FIBRE GROWTH

１．ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｎｃｅＩｉｊｉｍａｄｉｓｃｏｖｅｒｅｄｎａｎｏｃａｒｂｏｎｔｕｂｅｉｎ１９９１．Ｔｈｅｓｅｏｎｅｄｉｍｅｎｓｉｏｎａｌｎａｎｏｍａｔｅｒｉａｌｓｈａｖｅｉｍｐｏｒｔａｎｔｂａｓｅｓｔｕｄｙｖａｌｕｅａｎｄｐｏｔｅｎｔｉａｌａｐｐｌｉｃａｔｉｏｎｖａｌｕｅｂｅｃａｕｓｅｏｆｔｈｅｉｒｓｐｅｃｉｆｉｃｓｔｒｕｃｔｕｒｅｃｈａｒａｃｔｅｒｓａｎｄｎｅｗｐｈｙｓｉｃａｌｐｒｏｐｅｒｔｉｅｓｄｉｓｓｉｍｉｌａｒｔｏｔｈｅｂａｓｅｍａｔｅｒｉａｌｓ,ｎｏｗｔｈｅｙａｒ…     

Si粉微合金化对钢-铝复合材料界面的影响

采用粉末轧制工艺,在界面添加4％ Si粉进行界面微合金化调控,成功制备出界面结合良好的钢-铝复合材料.研究了界面微合金化设计、扩散退火处理工艺对钢-铝复合材料界面区元素扩散、生成物相的影响规律,探讨了元素Si界面调控的作用机理.结果表明:添加4％ Si粉界面微合金设计,在500℃扩散退火,保温1h热处理工艺下,复合材料界面未出现金属间化合物,600℃扩散退火,保温1h热处理工艺下,仅出现少量化合物Fe2Al5,Si粉界面微合金化处理能延缓界面化合物相生成,使生成Fe2Al5相的扩散温度向高温推移;Si扩散固溶到Fe、Al基体中形成连续固溶体,提高了界面两侧物理及力学性能的连续性,改善复合材料的界面结合.     

Solar-grade silicon production by metallothermic reduction

Various types of processes for solargrade silicon (SOG-Si) production/purification have been developed with the aim of overcoming the low productivity of the Siemens process. These processes can be divided into three groups: decomposition and/or hydrogen reduction of silane gases by improving the currently used commercial processes; purification of metallurgical-grade silicon using metallurgical purification methods; and metallothermic reduction of silicon halides by metal reductants such as zinc and aluminum. This paper reviews the features of various SOG-Si production processes, particularly the processes based on metallothermic reduction, by classifying them according to the types of reductants and the silicon compounds used. Prospects for development of new processes for producing high-purity silicon are presented.     

Mechanical properties of a fully dense polymer derived ceramic made by a novel pressure casting process

A new process has been developed for obtaining fully dense samples of silicon carbonitride (SiCN) from polymers. The process consists of two simple steps: cross-linking the liquid organic precursor under pressure, followed by controlled pyrolysis. Net shape processing is possible by casting the liquid into a mold before polymerization. The entire process is completed below 1000 °C. Basic mechanical properties of pore free SiCN made by this process were measured. The Youngs modulus is 155±10 GPa. The Vickers hardness increases from 15 GPa at an applied load of 1 N to 26 GPa at 3 N. Thus, the hardness to modulus ratio of these materials is two to three times higher than for crystalline silicon nitride or silicon carbide. The fracture strength of up to 1.1 GPa was measured. Pressure cast samples have a typical thickness of 0.3–0.5 mm, and are therefore suitable for obtaining a full range of fundamental properties of polymer derived ceramics.     

高硅铸铁的研究

研究了Cu和稀土对高硅铸铁的微观组织结构和性能的影响.试验结果表明在高硅铸铁中加入适量的Cu和稀土,可使石墨细化、组织细化和均匀化,并在晶界上有富Cu相析出,从而降低高硅铸铁的硬度,提高其塑性及耐蚀性.     

Materials challenges for terrestrial thin-film photovoltaics

The terrestrial photovoltaics market has been dominated from the beginning by crystalline silicon and by cast multicrystalline silicon. Continuing improvements in materials quality and innovative designs are responsible for keeping silicon solar cells at a market share of about 85%. However, in the past two years, thin-film solar modules based on amorphous silicon, cadmium telluride, and copper indium gallium diselenide have gained a strong foothold in the market, particularly in the United States and Europe. This article will briefly review the status of silicon solar cells and then discuss developments, opportunities, and materials challenges in thin-film solar cells.     

日本高磁感取向硅钢最新进展(I)

收集整理日本2004年度硅钢专利文献152项,其中高磁感Hi-B取向硅钢专利文献34项.Hi-B钢最新技术涉及诸多方面,主要有：开发新型抑制剂和高磁场用钢、研究低温板坯加热工艺、改进脱碳退火工艺、改善薄膜外观质量,采取措施降低铁损等,本文仅对其中的部分进行分析、研究,以供借鉴.     

Continuous melting and directional solidification of silicon ingot with an electromagnetic cold crucible

In order to avoid contamination from the crucible and to modify the structures,a new solidification method based on cold crucible technology was used to prepare silicon ingots.A silicon ingot with square cross section was directionally solidified with a cold crucible.The mechanism of the cold crucible directional solidification of silicon ingot was revealed.Due to the induction heat that was released in the surface layer and the incomplete contact between the crucible and the melt,the lateral heat loss was reduced and the silicon ingot was directionally solidified.The structures,dislocation defects and the grain growth orientation of the ingot were determined.The results show that neither intergranular nor intragranular precipitates are found in the ingot,except for the top part that was the last to solidify.The average dislocation density is about 1 to 2×106 cm-2.The grains are preferentially <220> orientated.     

Cross-sectional nanoindentation: a new technique for thin film interfacial adhesion characterization

Interfacial adhesion is becoming a critical material property for improving the reliability of multilayer thin film structures used in microelectronics. Cross-sectional nanoindentation (CSN) is a new mechanical test especially designed for measuring the fracture toughness of thin film interfaces. Interfacial fracture is achieved by nanoindentation in the structure cross-section. A model based on the elastic plate theory has been developed to calculate numerically the interfacial critical energy release rate (G_ci) for ceramic–ceramic systems from CSN test results. The model inputs are the thin film elastic properties, thin film thickness, interfacial crack area and maximum thin film deflection during the test. Closed form analytical solutions, obtained for two limiting cases, are consistent with the numerical approach. This technique has been successfully applied to silicon nitride–silicon oxide thin films, commonly used as electrical isolators in microelectronic devices.     

Reactive infiltration by Si: Infiltration versus wetting

This paper focuses on spontaneous infiltration by liquid metals in reactive metal/ceramic systems. Two cases of reactive infiltration, where a molten silicon drop is in contact with two different porous bodies, graphite and (oxidized) silicon nitride, are briefly described and discussed. For each solid, the dynamics of wetting on the solid surface is compared to the dynamics of infiltration into the porous medium in order to determine the common points and the main differences between these two processes.     

A new two-dimensional ultrasonic assisted grinding (2D-UAG) method and its fundamental performance in monocrystal silicon machining

A new two-dimensional (i.e., elliptical) ultrasonic assisted grinding (UAG) technique is proposed to achieve high material removal rate and high surface quality in the machining of hard and brittle materials such as monocrystal silicon. In this method, the workpiece attached on an elliptical ultrasonic vibrator is ground with a resin bond diamond grinding wheel under the presence of elliptical ultrasonic vibration. The elliptical ultrasonic vibrator is produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304) and its detailed structure/dimensions are determined by FEM (finite element method) analysis. When two alternating current voltages with a phase difference are applied to the PZT at the same frequency that is close to the resonant frequency of the longitudinal mode and bending mode of vibrator, two ultrasonic vibrations are generated simultaneously, and the synthesis of the vibrations results in an elliptical motion on the end face of the vibrator. If the phase difference is set at 0° or 180°, two kinds of one-dimensional ultrasonic vibrations, i.e., axial or vertical vibrations, can be obtained. Grinding experiments are carried out involving monocrystal silicon to confirm the performance of the proposed elliptical UAG. In addition, grinding experiments under the presence of the axial and vertical ultrasonic vibrations and the absence of ultrasonic vibrations, i.e., conventional grinding, are also carried out for comparison. The obtained results show that: (1) compared with conventional grinding, the axial ultrasonic vibration results in greatest improvement in the work surface quality and a slight reduction in the grinding forces; (2) under the vertical ultrasonic vibration, the grinding forces are decreased significantly but the surface roughness is increased slightly; (3) elliptical ultrasonic vibration leads to the significant reduction of both the surface roughness and grinding forces. These indicate that the high efficiency and high-quality grinding of monocrystal silicon can be performed with the proposed two-dimensional ultrasonic assisted grinding technique.     

Hypersonic plasma particle deposition—A hybrid between plasma spraying and vapor deposition

In the hypersonic plasma particle deposition process, vapor phase reactants are injected into a plasma and rapidly quenched in a supersonic nozzle, leading to nucleation of nanosize particles. These particles impact a substrate at high velocity, forming a coating with grain sizes of 10 to 40 nm. As previously reported, coatings of a variety of materials have been obtained, including silicon, silicon carbide, titanium carbide and nitride, and composites of these, all deposited at very high rates. Recent studies have shown that slight modifications of the process can result in nanosize structures consisting of single crystal silicon nanowires covered with nanoparticles. These nanowires are believed to grow in a vapor deposition process, catalyzed by the presence of titanium in the underlying nanoparticle film. However, simultaneously nanoparticles are nucleated in the nozzle and deposited on the nanowires, leading to structures that are the result of a plasma chemical vapor deposition (CVD) process combined with a nanoparticle spray process. The combination of these two process paths opens new dimensions in the nanophase materials processing area. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

CSP流程无取向硅钢中间品处理方案

结合内蒙古包钢钢联股份有限公司薄板坯连铸连轧厂利用CSP流程生产无取向硅钢的工艺特点，针对CSP流程在连浇过程中出现的诸如轧机换辊、铸机降速、工艺状态波动等情况下产出的过渡坯不能轧制成目标厚度的问题，利用厂里现有冷轧罩式炉、冷轧重卷分卷生产线，进行二次轧制、罩式退火、重卷扩径，处理了大量计划带出品，并得到了磁性能更好的硅钢产品。     

Ultrasonic characterization of porous silicon using a genetic algorithm to solve the inverse problem

This paper presents a method for ultrasonic characterization of porous silicon in which a genetic algorithm based optimization is used to solve the inverse problem. A one-dimensional model describing wave propagation through a water immersed sample is used in order to compute transmission spectra. Then, a water immersion wide bandwidth measurement is performed using an insertion/substitution method and the spectrum of signals transmitted through the sample is calculated using Fast Fourier Transform. In order to obtain parameters such as thickness, longitudinal wave velocity or density, a genetic algorithm based optimization is used.A validation of the method is performed using aluminium plates with two different thicknesses as references: a good agreement on acoustical parameters can be observed, even in the case where ultrasonic signals overlap.Finally, two samples, i.e. a bulk silicon wafer and a porous silicon layer etched on silicon wafer, are evaluated. A good agreement between retrieved values and theoretical ones is observed. Hypothesis to explain slight discrepancies is proposed.