Ni/Au、Pd/Au与p-AlGaN材料的接触特性

在AlGaNpin型日盲紫外探测器结构中的p-AlGaN层上生长了Ni/Au和Pd/Au,并在600～850℃温度下进行快速热退火,测量其退火前后传输线模型中各金属接触间的电学性质。实验发现,Ni/Au与Pd/Au在p-AlGaN上表现出了不同的接触性能。为了更好的说明金属与p-AlGaN材料接触之间在退火后电流的变化,还测量了p-AlGaN材料裸片两点之间I-V曲线在退火前后的变化。实验表明,比起Ni/Au来,Pd/Au在p-AlGaN材料上制备欧姆接触具有一定的优势,并在文中进行了分析。     

n-SiO2/Ni复合镀层组织与接触疲劳性能

采用电刷镀技术制备了含n-SiO2/Ni复合镀层,测试了镀层的抗接触疲劳性能,探讨了在镀液中加入纳米铜颗粒对镀层抗接触疲劳性能的影响.结果表明,n-SiO2/Ni复合镀层接触疲劳寿命可达到一百万次以上;在镀液中加入纳米铜后,镀层接触疲劳寿命大幅度降低.加入纳米铜后镀层结构呈连续的层状,疲劳裂纹在层间萌生并沿层间扩展,导致在较短循环周次内发生失效.     

Au/Ti/W/Ti与n-GaAs欧姆接触的特性研究

用磁控溅射系统和快速合金化法制备了Au/Ti/W/Ti多层金属和n-GaAs材料的欧姆接触,用传输线法对其比接触电阻进行了测试,并利用俄歇电子能谱(AES)和X射线衍射图谱(XRD)对接触的微观结构进行了研究。结果表明该接触在700℃时比接触电阻为1.5×10~(-4)Ω·cm~2,快速合金化后呈现欧姆特性可能与接触界面处生成的TiAs相有关。     

冲击环境下电连接器接触性能研究

冲击应力是影响电连接器接触性能的主要环境因素之一。针对传统试验成本高、耗时长且难以实现某些高强度环境试验的局限性,采用仿真方法研究冲击环境下电连接器接触件接触性能参数变化规律。结合理论力学基本原理,通过ANSYS建立电连接器接触件实物模型、动力学模块模拟冲击试验,分析了试验严酷等级、冲击脉冲持续时间及峰值加速度对接触件的形变、应力和接触压力等参数的影响,并对接触压力仿真结果进行试验验证。结果表明：冲击试验过程中,接触件形变受冲击影响最大;接触性能参数随严酷等级的增加,先缓慢增大后快速增大;随脉冲持续时间的增加,先急剧下降后缓慢减小;而在峰值加速度变化时基本保持稳定。由此可知,严酷等级和脉冲持续时间对电连接器接触性能参数变化起主导作用,仿真结果可为产品设计提供一定的理论参考。     

隔膜泵曲轴轴承半套装配体接触非线性有限元分析

隔膜泵曲轴部装包括:曲轴、连杆、轴承等零件。曲轴部装作为隔膜泵动力端的关键部件,在隔膜泵动力系统中发挥着重要作用。曲轴曲柄、半套和连杆轴承组成的系统是将曲轴的旋转运动转化为十字头直线往复运动的关键部件,半套的不同设计结构尺寸会导致其在运动过程中产生不同的受力状态和变形结果。本文利用ANSYS软件对曲轴曲柄、半套和轴承内圈组成的装配体进行接触非线性有限元分析。针对两种不同尺寸的半套结构分别进行分析,获得了计算结果,分析了半套和曲轴曲柄接触宽度对半套机械强度影响。分析结果对半套的设计有一定的指导意义。     

隔膜泵动力端轴承座和轴承半套装配体接触非线性有限元分析

隔膜泵动力端曲轴轴承作为动力端的关键部件,在隔膜泵传动系统中发挥着重要作用。它的安全、可靠运行决定着整个动力端的稳定运行。曲轴轴承通过半套与动力端下箱体装配在一起,下箱体轴承压块的不同结构形式决定着半套的受力状态。本文利用ANSYS软件对轴承座、轴承压块和半套组成的装配体进行接触非线性有限元分析。针对三种不同结构的轴承压块组成的轴承座装配体模型分别进行分析,获得了三种不同装配体结构的轴承座、轴承压块和半套的应力分析结果,从计算结果分析了不同轴承压块结构对轴承座装配体机械强度和变形的影响。分析结果对轴承座的设计有一定的指导意义。     

Zn+注入对p-GaN/Ni/Au欧姆接触特性的影响

首次采用离子注入工艺研究金属电极和p-GaN的欧姆接触特性.Zn为Ⅱ族元素,可以提高p-GaN表面的栽流子浓度,对p-GaN/Ni/Au(5/10nm)界面处进行Zn+注入.经Zn+注入后的样品在空气氛围中快速热退火处理5min,以减少离子注入带来的晶格损伤.研究发现Zn+注入改善了p-GaN/Ni/Au的欧姆接触特性,接触电阻率ρc从10-1Ω·cm2数量级降低到10-3Ω·cm2数量级.研究了不同Zn+注入剂量(5×1015、1×1016、5×1016cm-2)对接触电阻率的影响,在注入剂量为1×1016cm-2、300℃下退火得到最优的接触电阻率为1.45×10-3Ω·cm2.用扫描电子显微镜观察了离子注入前后的表面形貌变化,探讨了接触电阻率改变的内在机制.     

不同沉积工艺下Au/P-CdZnTe接触界面的研究

采用超声波扫描(SAM)、俄歇电子能谱分析技术(AES)、电极粘附力测试和I-V特性测试等方法研究了化学沉积、溅射和真空蒸发三种不同沉积工艺条件下Au/p-CdZnTe接触界面的各种特性.通过实验结果可以看出,化学法沉积的Au电极能形成较好的欧姆接触特性,但其操作工艺不容易控制,电极接触层均匀性较差,在器件使用过程中,容易引起电极的退化;溅射沉积的Au电极有着较好的附着力,但对CdZnTe表面的损伤较大,欧姆接触特性较差;真空蒸发法沉积的Au电极,有着较好的欧姆接触特性,且其电极接触层也较为均匀,只是电极附着力相对较小,但可以通过合适的退火工艺进行改善.     

SiC上Ti/Ni/Au多层金属的欧姆接触特性

采用Ti/Ni/Au多层金属在高掺杂n型4H-SiC外延层上制作了欧姆接触测试图形,通过传输线法(Transmission Line Method,TLM)测量得到的最小比接触电阻为1.4×10-5Ω·cm2,经500℃N2老化后接触电阻大约有一个数量级的增加并保持稳定.     

弱电接触材料的研究与发展

介绍了主要弱电接触材料的种类、特性和制备工艺.重点从节银弱电接触材料的研究进展、铜基无银材料和纳米复合材料3个方面对弱电接触材料的发展趋势做了详细的介绍.指出合金多元化复合材料的研究、纳米技术在电接触材料的应用以及新型制备方法的发展,是今后弱电接触材料发展的新方向.     

The effect of high temperature annealing on Schottky diode characteristics of Au/n-Si contacts

The current-voltage and capacitance-voltage characteristics of Au/n-Si/Al Schottky barrier diode were measured in the temperature range of 100-800 °C. Au/n-Si/Al Schottky barrier diode annealed at temperatures from 100 °C to 400 °C for 5 min and from 500 °C to 800 °C for 7 min in N₂ atmosphere. The electronic parameters such as barrier height and ideality factor (n) of the device were determined using Cheung's method. To determine whether or not a Schottky diode is ideal it can be used the ideality factor (n) found from its forward current-voltage (I-V) characteristics. It has been found that the value of Φ_b (0.82 or 0.83 eV) remains constant up to 500 °C and 0.80 and 0.79 eV in 600, 750 °C respectively in the forward I-V mode. An ideality factor value of 1.04 was obtained for as-deposited sample. The ideality factor n varied from 1.04 to 2.30. The experimental results have shown that the ideality factor (n) values increases with increasing annealing temperature up to 750 °C. This has been explained in terms of the presence of different metallic-like phases produced by chemical reactions between the Au and Si substrate because of the annealing process. The Φ_b (C-V) values obtained from the reverse-bias C⁻²-V curves of the as-deposited and annealed diode are in the range 0.99-1.12 eV. The difference between Φ_b (C-V) and the Φ_b (I-V) is in close agreement with values reported in literature. Besides Fermi energy level and carrier concentration determined by using thermionic emission (TE) mechanism show strong temperature dependence. It has been seen current-voltage characteristics of the diode show an ideal behavior.     

两步镀膜Ti/Al/Ti/Au的n型GaN欧姆接触研究

报道了一种可靠稳定且低接触电阻的n型GaN欧姆接触。首先在掺硅的n型GaN(3×1018cm-3)蒸镀Ti(30nm)/Al(500nm),然后在氮气环境530℃合金化3min,最后蒸镀Ti(100nm)/Au(1000nm)用于保护Al层不被氧化。该接触电极有良好的欧姆接触特性,比接触电阻率为8.8×10-5Ωcm2,表面平坦、稳定、易焊线,可应用于制作高性能的GaN器件.     

Photovoltaic and interface state density properties of the Au/n-GaAs Schottky barrier solar cell

The electrical and photovoltaic properties of the Au/n-GaAs Schottky barrier diode have been investigated. From the current-voltage characteristics, the electrical parameters such as, ideality factor and barrier height of the Au/n-GaAs diode were obtained to be 1.95 and 0.86 eV, respectively. The interface state distribution profile of the diode as a function of the bias voltage was extracted from the capacitance-voltage measurements. The interface state density D_it of the diode was found to vary from 3.0 × 10¹¹ eV⁻¹ cm⁻² at 0 V to 4.26 × 10¹⁰ eV⁻¹cm⁻² at 0.5 V. The diode shows a non-ideal current-voltage behavior with the ideality factor higher than unity due to the interfacial insulator layer and interface states. The diode under light illumination exhibits a good photovoltaic behavior. This behavior was explained in terms of minority carrier injection phenomenon. The photovoltaic parameters, such as open circuit voltage and short circuit current density were obtained to be 362 mV and J_sc = 28.3 μA/cm² under AM1, respectively.     

Structural and electrical properties of Au and Ti/Au contacts to n-type GaN

Au and Ti/Au layers were deposited on n-GaN. The samples were annealed at 400, 700 and 900 °C for 10 min in vacuum. The contacts were rectifying up to 700 °C and the highest Schottky barrier height of 1.07 eV was obtained for an Au single layer by current-voltage measurements. A binary phase of Au₂Ga was identified at the interface of the n-GaN/Ti/Au contact after annealing at 900 °C. The formation of Ti₂N and TiN (twin) phases epitaxially grown on GaN was also observed in the same contact as well as some gold diffusion into the topmost region of the GaN epilayer.     

Fabrication of Au/Ti TESs for Optical Photon Counting

High efficiency and negligible dark-count rates of transition-edge sensor (TES) microcalorimeters as single photon detector at telecommunications and optical visible wavelengths make them powerful tools for quantum information and quantum computation. In this work we report details on the fabrication of Au/Ti for photon counting and analyse the effects on the critical temperature and the transition steepness of the structuring process and wiring material. Au/Ti films deposited by electron-beam at substrate temperature lower than 435 K show sharp transition and reproducible T _c . Moreover, we observe that TES with Al wiring are more stable and have better characteristics of TES with Nb wiring. Using 20 micron×20 micron Ti/Au TES single photon detection has been obtained in the UV-visible range.      

The effect of Cr barrier on interfacial reaction of Au/Zn/Au/Cr/Au contacts to p-type InGaAs/InP

Alloy-type metal is widely used to reduce contact resistance in optoelectronic devices. Among the alloy-types, Au/Zn is one of the most common metallization systems. In this paper, we studied the alloy morphology of p-InP/p-InGaAs/Au/Zn/Au/Cr/Au systems. We found that the amount of Au-Zn alloy depended upon the thickness of the Cr layer. When Cr thickness was reduced to 135 Å, both Au-rich and GaAs-rich excessive compound formation started to occur. The Au diffusion punched through the InGaAs layer and penetrated into the InP. Comparison of Au/Zn/Au and Au/Zn/Au/Cr/Au suggested that the top Au layer maybe very influential during the alloy reaction. The Au-Zn alloy was significantly less in the Au/Zn/Au than that in the Au/Zn/Au/Cr/Au.     

CdZnTe晶体表面Au电极薄膜的制备及其欧姆接触性质

为了研究不同制备工艺对电极欧姆接触特性的影响, 分别采用真空蒸发法、溅射法及化学沉积法在CdZnTe晶片表面制备了Au薄膜电极, 通过测试样品的SEM、I-V曲线及交流阻抗谱, 研究了不同电极制备工艺及退火处理对Au薄膜电极的微观结构及欧姆接触特性的影响。结果表明化学沉积法制备的Au薄膜表面更加平整、致密, 接触势垒的高度较低, 电极欧姆接触特性最好。退火处理可以改善电极的欧姆接触特性, 100℃退火后, 化学沉积法制备的Au电极的欧姆系数由0.883提高至0.915, 势垒高度由0.492降低至0.487 eV。交流阻抗谱分析表明, 化学沉积法制备电极具有最低的接触势垒, 这与界面处晶片表面的掺杂及缺陷的变化有关。     

Analysis of high contact resistance in silver impregnated graphite (SIG) contacts

Silver impregnated graphite (SIG) contacts are used in high safety applications of railway signaling, traffic signaling, and numerous other applications due to high silver content that eliminates the risk of welding in the presence of graphite. High contact resistance (>200 mΩ) was observed in SIG contacts in a railway signaling operation after a few thousand operations of the relay. The high contact resistance was discovered to be a result of loose dust/foreign particles residing between the two contacts. Silver had been preferentially removed from the contacting surfaces during switching operations by an abrading effect of the dust/foreign particles, leaving only graphite on the contact area. Wear was accentuated by the presence of porosity and low hardness of the contacts, leading to improper interaction between the mating surfaces.