Au-Ni-Sn三元合金在铅基和无铅基焊点界面的生长抑制

以前研究：BGA、Pb-Sn焊料／Au／Ni组成的焊点，经过几个小时150℃的退火处理后呈现出连续层状的三元合金(Au，Ni)Sn4，它紧邻Ni3Sn4层。Ni3Sn4层发生在焊料与Ni的界面上。在界面形成的双层结构金属间化合，导致焊点性能变差。这是我们不希望的。这个发现促进了后来的研究，并由这些研究得知在界面三元合金生长，强烈依赖焊点的金属组成和再流焊条件。在本次研究中，我们集中注意再流焊条件(温度和液相线以上的时间)和焊料组成，对在不同焊点上，三元化合物(Au，Ni)Sn4生长，形态和位置的影响。我们研究的焊点是由0．1Au-99．9Sn或者26Pb-73．9Sn-0．1Au(原子百分含量，除非特殊注明)的焊料在Ni基板上经过再流焊形成。以及研究94．35Sn-3．8Ag-1．85Cu在金／镍金属面上再流焊形成的焊点。26Pb-73．9Sn-0．1Au焊料合金在Ni基板、在185℃液相线以上30秒，进行再流焊。随后150℃退火处理。在基板界面上产生二层金属间化合物：Ni3Sn4和(Au，Ni)Sn4.但是这些焊料合金在235℃，液相线以上经过30秒的再流焊，只有一个层Ni3Sn4生长在26Pb-73．9Sn-0．1Au与Ni的界面上。而(Au，Ni)Sn4三元物在焊料体中形成，与此相似，(Au，Ni)Sn4沉积物：出现在244℃峰值温度，液相线以上74秒再流焊形成的SnAgCu／Au／Ni焊点体中。这个三元中铜的百分含量小于1％，经过261个小时的150℃温度退火处理后这个三元化合物仍留在焊点中。对于Au0．1Sn99．9／Ni系统，经过260℃，液相线以上46秒的再流焊和150℃，49小时的退火处理只有一层Ni3Sn4在焊料与基板界面生长。     

Ni/Au与p-GaN的比接触电阻率测量

通过采用环形传输线方法(CILM),电流-电压(I-V)曲线、表面形貌等方法,研究不同的Ni/Au厚度比和空气气氛下合金退火温度对p型氮化镓欧姆接触特性造成的影响。根据Ni/Au与p型氮化镓欧姆接触的形成机制,采用合适的Ni/Au厚度比及退火温度,得到比接触电阻率(ρc)为1.09×10-5Ω.cm2的Ni/Au-p-GaN电极,并分析了Ni在退火过程中对形成良好的欧姆接触中所起到的作用。     

LiNbO3:Fe:Ni晶体非挥发全息存储研究

采用三种不同的双光记录方案进行了LiNbO3：Fe：Ni晶体全息存储实验．详细研究了饱和衍射效率、固定衍射效率、动态范围和记录灵敏度，以及退火条件对记录的影响。结果表明，氧化LiNbO3：Fe：Ni晶体的饱和衍射效率、固定衍射效率和记录灵敏度比其他报道的双掺杂LiNbO3晶体高。结合掺杂能级图，理论分析了LiNbO3双掺杂晶体深陷阱中心能级的相对位置及其微观光学参量对全息记录性能的影响。LiNbO3：Fe：Ni晶体有望成为一种新的高效率非挥发全息存储材料。     

纳米Fe-In2O3颗粒膜的低温磁效应

采用射频溅射法制备了纳米Fe—In2O3颗粒膜，研究了颗粒膜在低温下的两种特殊磁效应——巨磁电阻效应和磁性弛豫效应。磁电阻测量结果表明，当Fe体积分数为35％时，颗粒膜样品的室温磁电阻变化率(△ρ/ρ0)为4．5％，而在温度T=2K时，∑ρ／ρ0达85％。根据颗粒膜低场磁化率-温度(x-T)关系证实，在一定温度下，颗粒膜中纳米Fe颗粒表现出磁性弛豫效应，当截止温度TB=50K时，颗粒膜的磁特性由超顺磁性转变为铁磁性；在截止温度以上，其饱和磁化强度与温度关系符合Bloch的T^3/2定律。     

Ni基n型SiC材料的欧姆接触机理及模型研究

研究了Ni基n型SiC材料的欧姆接触的形成机理,认为合金化退火过程中形成的C空位(Vc)而导致的高载流子浓度层对欧姆接触的形成起了关键作用。给出了欧姆接触的能带结构图,提出比接触电阻ρC由ρC1和ρC2两部分构成。ρC1是Ni硅化物与其下在合金化退火过程中形成的高载流子浓度层间的比接触电阻,ρC2则由高载流子浓度层与原来SiC有源层之间载流子浓度差形成的势垒引入。该模型较好地解释了n型SiC欧姆接触的实验结果,并从衬底的掺杂水平、接触金属的选择、合金化退火的温度、时间、氛围等方面给出了工艺条件的改进建议。     

MgO缓冲层对Si衬底上制备Fe3Si薄膜性能的影响

采用磁控溅射方法和热加工工艺在n型Si衬底上溅射不同厚度的MgO层并制备Fe-Si薄膜层,退火后形成Fe3Si/MgO/Si多层膜结构.利用MgO缓冲层对退火时Si衬底扩散原子进行屏蔽,并分析MgO层对Fe3Si薄膜结构和电学性质的影响.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和四探针测试仪对Fe3Si薄膜的晶体结构、表面形貌、断面形貌和电阻率进行表征与分析.研究结果表明:当MgO层厚度为20 nm时生成Fe0.9Si0.1薄膜,当厚度为50,100,150和200 nm时都生成了Fe3Si薄膜,生成的Fe3Si和Fe0.9Si0.1薄膜以(110)和(211)取向为主.随MgO缓冲层厚度增加,Si衬底扩散原子对Fe3Si薄膜的影响减小,Fe3 Si薄膜的晶格常数逐渐减小,晶粒大小趋向均匀,平均电阻率呈现先增大后减小趋势.研究结果为后续基于Fe3 Si薄膜的器件设计与制备提供了参考.     

基于Ni/Ag/Pt的P型GaN欧姆接触

提出了新型的Ni/Ag/Pt结构作为具有高光学反射率、低比接触电阻率(SCR)的p-GaN欧姆接触电极。在Ni/Ag/Pt厚度分别为3 nm/120 nm/2 nm的条件下,在500℃、O2气氛中退火3 min,获得了80%的光学反射率(460 nm处)和4.43×10-4Ω.cm2的SCR,样品的表面均方根(RMS)粗糙度约为8nm。俄歇电子能谱(AES)分析表明,Pt很好地改善了Ag基电极退火后的表面形貌,Ni、Ag对形成良好的欧姆接触起了重要的作用。     

退火对Fe/Si结构原子间互扩散及显微结构的影响

在Si(100)衬底上,用直流磁控溅射沉积约100nm的纯金属Fe膜,然后在600～1000℃真空退火2h.用能量为3MeV的C离子进行了卢瑟福背散射(RBS)测量,并用SIMNRA 6.0程序分析了测量结果,给出了界面附近Fe原子与Si原子间互扩散的完整图像.扫描电镜(SEM)观察和X射线衍射(XRD)测量表征了不同温度退火2h后Fe/Si系统表面的显微结构和晶体结构.由RBS、XRD测量与SEM观察结果,分析了退火过程对磁控溅射制备的Fe/Si双层膜结构原子间的互扩散行为、硅化物形成及显微结构的影响.     

Ni掺杂量对Fe_3Si合金微波吸收性能的影响

利用机械合金化-真空退火工艺制备了Fe75–xNixSi25(x=0,2.5,5,7.5)合金,借助SEM、XRD和矢量网络分析仪等分析了Ni掺杂量对Fe3Si合金的微观结构和吸波性能的影响。结果表明:随着Ni掺杂量的增加,退火后的合金粉末的平均晶粒尺寸先减小后增大、微波吸收能力先增强后减弱。当Ni掺杂量为摩尔分数2.5%时,所制Fe72.5Ni2.5Si25合金粉末的吸波能力最强,当涂层厚度为4 mm时,该样品的吸收峰频率和峰值分别为7.5 GHz和–14.7dB,在2~10 GHz其反射率低于–5 dB的频带宽度达到了5.2 GHz,显示出良好的微波吸收宽频特性。     

Pt层对Ni/Si(100)固相反应NiSi薄膜高温稳定性的增强效应

研究了顺次淀积在Si(100)衬底上的Ni/Pt和Pt/Ni的固相硅化反应．研究发现,当1nm Pt作为中间层或覆盖层加入Ni/Si体系中时,延缓了NiSi向NiSi2的转变,相变温度提高．对于这种双层薄膜体系,800℃退火后,XRD测试未检测到NiSi2相存在;850℃退火后的薄膜仍有一些NiSi衍射峰存在．800℃退火后的薄膜呈现较低的电阻率,在23—25μΩ*cm范围．上述薄膜较Ni/Si直接反应生成膜的热稳定性提高了100℃以上．这有利于NiSi薄膜材料在Si基器件制造中的应用．     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NOTICE OF CHANGING JOURNAL OF ELECTRONICS （CHINA） TO MICROSYSTEMS ＆ NANOENGINEERING

正Journal of Electronics(China)(JE)was founded in 1984,sponsored by the Institute of Electronics,Chinese Academy of Sciences.JE is one of the first English academic journals in China in the field of Electronics and Information technology.The journal was published quarterly since it was launched in 1984 to 2003,then it is published bimonthly till now.During