高质量立方氮化硼薄膜的射频磁控溅射制备及其性能表征

运用射频磁控溅射法在硅片上制备了立方氮化硼薄膜,并对射频功率、气体分压比及衬底偏压等参数对膜中立方氮化硼(c-BN)含量的影响进行了研究.采用傅立叶红外光谱(FTIR)、拉曼光谱、X射线光电子能谱(XPS)和原子力显微镜(AFM)对c-BN薄膜进行了表征和分析.结果表明:300 W的射频功率是制备c-BN薄膜的最佳条件;当气体分压比Ar/N2=5:1时,制备的薄膜中c-BN含量相对最高;立方氮化硼的形成存在偏压阈值(约80 V),低于此偏压c-BN很难形成.拉曼光谱分析进一步确认了BN薄膜的晶相结构.AFM和XPS分析结果表明c-BN薄膜结晶良好,晶粒尺寸细小,具有很好的化学配比,B原子与N原子的含量比为1:l.     

工作气压对制备立方氮化硼薄膜的影响

本文报道了工作气压对射频溅射法制备立方氮化硼(c-BN)薄膜影响的实验结果.c-BN薄膜沉积在p型Si(100)衬底上,溅射靶为六角氮化硼(h-BN),工作气体为Ar气和N2气混合而成,薄膜的成分由傅里叶变换红外吸收谱标识.结果表明,与射频功率、衬底温度和衬底负偏压一样,工作气压也是影响c-BN薄膜生长的重要参数.要得到一定立方相含量的氮化硼薄膜,必须要有合适的工作气压,否则,薄膜中不能形成立方相.在工作气压为5×10-3乇时,得到了立方相含量在90%以上的立方氮化硼薄膜.     

液-固界面反应法制备c-BN纳米晶

通过高能脉冲激光诱导丙酮-六方氮化硼界面反应制备出了立方氮化硼纳米晶体,透射电子显微镜分析表明制备的立方氮化硼(c-BN)纳米晶体为直径约30～80nm的类球状晶体。傅立叶变换红外光谱和X射线衍射都分别用来表征c-BN的结构。     

高速钢基体离子注氮对c-BN薄膜制备的影响研究

采用射频磁控溅射法在离子注氮的高速钢基体上沉积制备c-BN薄膜,主要研究离子注氮层对c-BN薄膜相结构和内应力的影响;采用各种现代分析方法对沉积的薄膜进行了表征分析,包括傅立叶红外光谱(FTIR)、X射线光电子能谱(XPS)和原子力显微镜(AFM)等分析方法;试验结果表明:高速钢基体上离子注氮有利于立方氮化硼含量的提高和薄膜内应力的降低,同时注氮处理的高速钢基体上沉积的薄膜表面形貌平整,结晶性较好.并采用X射线衍射分析(XRD)对高速钢基体的离子注氮层进行了相结构分析,探索研究了离子注氮层对c-BN薄膜生长的影响.     

c-BN薄膜的生长机制

立方氮化硼(c-BN)薄膜因其优异的机械、电学特性而有着广泛的应用前景.本文在大量的实验研究基础上,阐明衬底温度和荷能粒子轰击的重要作用,并综合分析了其他研究者的结果,较全面地论述了c-BN薄膜沉积过程中非晶层和h-BN层的形成以及c-BN相的形核长大机制.     

射频溅射两步法制备立方氮化硼(c-BN)薄膜

~~射频溅射两步法制备立方氮化硼(c-BN)薄膜@冯贞健$北京工业大学教育部新型功能材料重点实验室!北京100022 @邢光建$北京工业大学教育部新型功能材料重点实验室!北京100022 @陈光华$北京工业大学教育部新型功能材料重点实验室!北京100022 @于春娜$北京工业大学教育部新型功能材料重点实验室!北京100022 @荣延栋$北京工业大学教育部新型功能材料重点实验室!北京100022~~~~~~~~     

脉冲偏压下沉积的立方氮化硼膜的断面结构研究

采用自行研制的磁增强活性反应离子镀系统，在脉冲偏压条件下成功地合成了高品质立方氮化硼（c-BN）薄膜。用傅立叶变换红外谱（FTIR）分析沉积膜的相结构，用透射电镜（TEM）及高分辨率透射电镜（HRTEM）分析膜的断面结构。FTIR结果表明：c-BN的纯度强烈地受基片负偏压 的影响，当基片负偏压为155V，c-BN膜的纯度高达90%以上，TEM及HRTEM对膜的断面结构分析表明，在膜与基片的界面处存在很薄的非晶氮化硼和六万氮化硼（h-BN）层，h-BN（0002）晶面垂直于基片段面，在界面层之上生长着单相c-BN层。     

功能材料与器件学报 第十卷（2004）总目录

微型夹钳的最新研究王晓东刘冲王立鼎(1)氮化碳薄膜的电化学沉积及其电阻率研究李超曹传宝吕强张家涛项顼朱鹤孙(9)射频溅射两步法制备立方氮化硼(c-BN)薄膜冯贞健邢光建陈光华于春娜荣延栋(14)V2O5薄膜结构和性能研究许昱贺德衍(19)电子束蒸发沉积制备高度晶体取向的CeO2薄膜金波李炜郑志宏王曦(24)掺Er-Al2O3薄膜发光特性的研究肖海波张峰张昌盛程新利王永进陈志君林志浪张福民邹世昌(29)快淬速度对(Nd,Pr)10.5(FeCoZr)83.5B6显微结构和磁性能的影响查五生刘颖高升吉涂铭旌(33)SC铸片微结构对烧结NdFeB结构与磁性能的影响王标刘汉…     

立方氮化硼薄膜制备与性质研究新进展

立方氮化硼(c-BN)具有优异的物理和化学性质, 在力学、光学和电子学等方面有着广泛的应用前景. 自上世纪80年代开始, 低压沉积c-BN薄膜的研究迅速发展, 到90年代中期达到高潮, 随后进展缓慢, c-BN薄膜研究转入低潮. 近年来, c-BN薄膜研究在几方面取得了突破, 如获得与衬底粘附良好、厚度超过1μm的c-BN厚膜; 成功实现了c-BN单晶薄膜的异质外延生长; 此外, 在c-BN薄膜力学性质和过渡层微结构研究方面也取得了进展. 本文主要评述最近几年c-BN薄膜研究在以上几方面取得的最新进展.     

氮化硼薄膜在退火相变中的应力研究

利用射频溅射系统在P型Si（100）衬底上制备氮化硼薄膜。对其进行600～1000℃的常压下N2保护退火。通过傅立叶变换红外谱（FTIR）分析，发现hBN-cBN-hBN的可逆相变。通过不同温度退火后立方相横光学振动模式峰位的移动，计算了氮化硼薄膜中残余应力的变化。发现沉积后退火很好地解决了高立方相氮化硼薄膜应力释放的问题，可提高立方氮化硼薄膜在硅衬底上的粘附性。并且探索性地讨论在退火过程中c-BN成核、生长与薄膜中应力变化的关系。     

Economic Growth Revisited

In this essay it is suggested that the success of Japan andthe newly industrialized countries (NICs) is, in no small measure,due to their intuitive grasp of the relationships between technology,growth and economic policy as these countries constantly adjustedeconomic policy to reflect changed economic circumstances, withconcomitant changes in economic structure. The key element tothe explanation in this paper is ‘economic organization’.Economic organization refers to more than the simple dichotomybetween ‘centralization’ and ‘decentralization’of decision making at the highest level. As is now widely recognized,market economies consist of many firms; these firms, however,may be organized in different ways. At one extreme each maybe highly centrally controlled, in which case the economy canbe thought of as a polyarchy of hierarchies. There are two aspectsof economic organization of particular relevance: the abilityto monitor and to innovate. Changes in technology have profoundeffects on how well different organizational structures canperform these central functions and, on the other hand, an importantaspect of economic development is organizational innovationswhich affect the ability of the economic system to monitor andinnovate. Moreover, the performance of an economy depends notjust on the internal organization of its firms and the marketstructure; it depends on how well capital markets function.These too may be organized in markedly different ways. The paperis organized into six sections. The first describes the majorphenomena to be explained, the stylized facts with which anyexplanation of growth must come to terms. The second and thirddiscuss the two competing explanations—explanations whichemphasize returns to scale and factor accumulation—andargue that these explanations cannot account for * The authoris a member of the Council of Economic Advisors, on leave fromStanford University The views expressed are solely those ofthe author. This paper is based on research which was supportedin part by the National Science Foundation, the Sloan Foundation.the Hoover Institution and the World Bank My ideas on the growthprocess have been greatly influenced by an extended study ofthe East Asia miracle, sponsored by the World Bank. For fullerdiscussions of the East Asia miracle, see World Bank (1993).Stiglitz (1994a) and Stiglitz and Uy (1994). This paper incorporatesand excends ideas developed there as well as those presentedin several earlier papers, in particular Stiglitz (1992a). Theinfluence of my co-authors Bruce Greenwald. Andrew Weiss, ThomasHellmann, Andres Rodriguez, Kevin Murdock and Marilou Uy shouldbe evident.     

Si纳米线的生长机制及其研究进展

si纳米线及其阵列是近年内新发展起来的准一维半导体光电信息材料,在场效应器件、单电子存储器件、光探测器件、场发射器件、纳米传感器件和高效率发光器件以及集成技术中具有潜在的应用.本文以气-液-固(VLS)生长机制为主线,介绍与评论了近5年来Si纳米线在制备与合成技术方面所取得的一些最新进展.其主要内容包括Si纳米线的各种金属催化生长和氧化物辅助生长,最后指出了今后该研究的发展方向.     

Growth Mechanism in Infiltration Growth Processed YBCO Composites Through Quench Studies

The mechanism of YBa₂Cu₃O_7?x (Y123/YBCO) growth and the dispersion of Y₂BaCuO₅ (Y211) particles in YBCO composites were investigated at various stages during infiltration growth process by quenching the samples in liquid nitrogen from different temperatures (1005, 1010 and 1045 °C) through peritectic reaction. Structural details of the samples were investigated using X-ray diffraction, microstructural and elemental analysis was carried out to study the distribution and composition of the matrix and Y211 inclusions at different stages. The present studies reveal that breaking down of sintered Y211 particles on application of pressure and slow cooling to 1005 °C allow sufficient infiltration of liquid phases. Peritectic reaction of liquids with Y211 particles caused rounding up of the broken sharp edges and their refinement leading to distribution of very fine Y211 precipitates in Y123 matrix.     

Root Growth Patterns and Morphometric Change Based on the Growth Media

Arabidopsis thaliana roots skew with minimal waving in the microgravity environment of the International Space Station. Root skewing and root waving have been studied on the ground as well as in spaceflight, but often using different media types. In this study, Arabidopsis seedlings were grown on nutrient media plates that were comprised of various gelling agents with varied hardness in order to better assess these media for spaceflight research experiments. ImageJ was used to quantify the root morphology of 8-dayold seedlings, while R was used to perform statistical analyses. Root growth was drastically different between Difco agar, agarose, and Phytagel. Additionally, root waving masked skewing in certain media. Regression analysis revealed overall patterns when organized by hardness but also revealed that differences in media type had more of an impact on root growth than hardness itself. Different arrangements of media around the root tip revealed that roots grown on the media surface were longer and had fewer waves per millimeter than roots grown embedded in media. The implications for spaceflight research are discussed.