金刚石表面离子束金属化研究

采用离子束增强沉积技术对金刚石热沉材料表面金属化进行了研究，制备了Ｔｉ／Ｎｉ／ＡｕＩｎ和ＣＵ／ＡｕＩｎ金属化体系。采用俄歇、ＥＤＳ、ＸＲＤ和ＳＣＲＡＴＣＨ方法对膜层和界面进行了分析。     

一种具有微处理器接口的CMOS12位电流型D／A转换器

研究了采用译码的分段梯形电阻网络技术制作的高速１２位ＣＭＯＳ电流型Ｄ／Ａ转换器，将常规的Ｒ－２Ｒ电阻网络和译码的权电阻网络相结合，解决了常规ＣＭＯＳＤ／Ａ转换器必须采用精密Ｒ－２Ｒ梯形电阻网络的问题，降低对电阻精度区配的要求。     

SCB－1型单片单板机的实用性改进

ＳＣＢ－１单片单板机以８０３１为核心，配有Ａ／Ｄ、Ｄ／Ａ、串并行口、键盘、显示器、存贮器、监控程序等软硬资源，适用于教学实验、工业过程控制和应用开发，但在使用过程中，发现软硬件设计均有欠缺之处。本文对此作了分析，介绍了实用改进方法。它可克服原Ｄ／Ａ饱和非线性，扩大Ａ／Ｄ范围，提高运行稳定性，增加内部ＲＡＭ访问、外部ＲＡＭ保护与串行通讯功能，使ＳＣＢ－１应用性能增强。     

CDMA/FM接收AGC和解调器芯片RF9957及其应用

ＲＦ９９５７是ＲＦＭｉｃｒｏＤｅｖｉｃｅ公司生产的一种带接收ＡＧＣ的ＣＤＭＡ／ＦＭ解调器芯片。它在内部集成了完整的中频自动增益控制（ＡＧＣ）放大器和正交解调器 ,可用于双模式的ＣＤＭＡ／ＦＭ蜂窝移动通信系统和ＰＣＳ系统。该芯片在对接收ＩＦ信号进行放大时 ,可提供１００ｄＢ的增益控制范围 ,并可将中频信号解调为Ｉ和Ｑ通道信号。该芯片的关键指标（如噪声系数和ＩＰ３等）与ＣＤＭＡ蜂窝移动通信系统标准ＩＳ -９８和Ｊ -ＳＴＤ -０１８兼容。ＲＦ９９５７采用先进的硅双极工艺（ＦＴ＝１５ＧＨｚ）设计制造 ,并使用标准的…     

CADDS5在VCR连接器CAD／CAM中的应用

ＣＡＤＤＳ５在ＶＣＲ连接器ＣＡＤ／ＣＡＭ中的应用·工艺设计·镇江接插件总厂张忠顺孙金曦朱元珍１前言镇江接插件总厂在“七五”期间为彩电配套连接器、显象管管座国产化生产工艺进行了技术改造，引进ＣＡＭ精密数控机床设备，包括瑞士ＡＣＩＥＲＡ公司的数控铣床Ｆ３...     

扩展DS12887一个经验

扩展ＤＳ１２８８７一个经验江苏省淮阴工专电气系赵正敏ＤＳ１２８８７是一种ＣＭＯＳ工艺的ＲＴＣ／ＲＡＭ器件，广泛用于各种具有实时钟及非挥发ＲＡＭ的计算机系统中，图１是该器件用在ＭＣＳ５１系统中的电原理图。我们发现，在没有采用虚框部分时，从ＤＳ１２８８...     

机械结构CAD产品建模的关键技术

本文从工程应用角度探讨了机械ＣＡＤ／ＣＡＭ中产品几何造型的关键技术－曲面造型、实体造型。研究了其中ＮＵＲＢＳ技术、Ｂ－ｒｅｐ法、ＣＳＧ法的理论以及在当今ＣＡＤ系统中的应用状况。     

HP37717/8分析仪对测试结果的记录方法

ＨＰ３７７１７／８（传输综合分析仪）是对２Ｍ～２．５Ｇｂｉｔ／ｓ传输速率的ＰＤＨ／ＳＤＨ设备 (系统 )进行测试和分析的主要仪表之一。它对测试结果的记录有ＤＩＳＫ(磁盘 )、ＩＮＴＥＲＮＡＬ、ＲＳ２３２ＨＰＩＢ、和ＰＡＲＡＬＬＥＬ等多种方法。本文重点介绍采用ＤＩＳＫ方式对抖动测试的模板图形结果、系统误码的图形和数字结果进行记录的方法 ,并对各种记录方法作了比较。１ＤＩＳＫ方法ＨＰ３７７１７／８分析仪经常采用ＤＩＳＫ方式记录测试结果。测试结果可以从测试期间到被下一次测试的结果所覆盖之前的任何时刻存入磁盘。…     

单斜率模数转换技术

在Ｍｏｔｏｒｏｌａ微控制器中，Ａ／Ｄ转换的最常用的实现方法是逐次近似（ＳＡＲ）法。采用ＳＡＲ法的典型的Ａ／Ｄ转换器具有８位的分辨率和１０到１６个时钟周期的转换时间。转换速率是ＳＡＲＡ／Ｄ的优点之一，但是出于许多理由，要把它的分辨率增加到８位以上是困难...     

市区多径衰落信道中的TCM DS／SSMA系统性能分析

本文将网络编码调制（ＴＣＭ）应用于市区多径衰落信道下的直接序列扩频多址（ＤＳ／ＳＳＭＡ）系统中，应用ＤＳ条件下市区多径衰落信道的等效模型，提出了一种采用理论分析和数值模拟相结合分析ＴＣＭＤＳ／ＳＳＭＡ系统在该信道下性能的新方法，并将传统的Ｕｎｇｅｒｂｏｅｃｋ型ＴＣＭ才本文所构成的若干种低码率ＴＣＭＤＳ／ＳＳＭＡ系统的性能进行了比较。     

用于高亮LED的Si键合研究

在Si和外延层之间使用一层薄金属层作为高效反射镜的所谓"镜面衬底",不但有助于提高芯片的出光效率,同时把键合温度降低到300℃以下。利用Au/In合金的方法,来实现用于高亮LED的Si片与AlGaInP四元外延片的键合。实验表明,在温度为250℃时,利用Au/In作为焊料,Si片与AlGaInP四元外延片可以实现比较好的键合,键合面可以达到60%。通过研磨减薄、X-ray测试和扫描电镜(SEM)测试得出键合面的界面特性,通过能谱分析得出键合面的物质分别为AuIn2和AuIn,实验测试得出此时Au的原子数占33.31%,In的原子数占36.64%。     

Electromigration in aluminum/silicon/copper metallization due to the presence of a thin oxide layer

The effect of a thin layer of SiO₂ (50 nm) on the electromigration behavior of Al/ 0.8wt.%Si/0.5wt.%Cu metallization, passivated by spin-on-glass, phosphorus silicate glass and silicon nitride as part of the complementary metal oxide semiconductor technology fabrication process was studied. It is found that voids were formed along the edge of the metallization line as opposed to formation at triple point of grain boundaries. At the same stress current of 1 × 10⁶ A/cm², thicker metallization layer (600 nm) showed an improvement in median time to failure (MTF) (1.4 times) with smaller void size (0.2 to 0.4 μm) over one without an underlying oxide, whereas if the metallization thickness is thin (300 nm), the MTF is degraded (0.6 times) with larger void size formed (0.3 to 1.0 μm).     

采用Ti/TiW/Au栅制作Si衬底上CaAs MESFET与集成电路

本文从制备硅集成电路(SiIc)与砷化镓集成电路(GaAs IC)单片兼容电路的要求出发,提出了Ti/TiW/Au肖特基金属化结构,制备出了性能良好的Ti/TiW/Au栅Si衬底上分子束外延(MBE)的GaAsMESFET与GaAs IC。     

Study on the failure temperature of Ti/Pt/Au and Pt5Si2-Ti/Pt/Au metallization systems

The Ti/Pt/Au metallization system has an advantage of resisting KOH or TMAH solution etching. To form a good ohmic contact, the Ti/Pt/Au metallization system must be alloyed at 400℃. However, the process temperatures of typical MEMS packaging technologies, such as anodic bonding, glass solder bonding and eutectic bonding, generally exceed 400℃. It is puzzling if the Ti/Pt/Au system is destroyed during the subsequent packaging process. In the present work, the resistance of doped polysilicon resistors contacted by the Ti/Pt/Au metallization system that have undergone different temperatures and time are measured. The experimental results show that the ohmic contacts will be destroyed if heated to 500℃. But if a 20 nm Pt film is sputtered on heavily doped polysilicon and alloyed at 700℃ before sputtering Ti/Pt/Au films, the Pt₅Si₂-Ti/Pt/Au metallization system has a higher service temperature of 500℃, which exceeds process temperatures of most typical MEMS packaging technologies.     

Investigation of microstructural processes during ultrasonic wedge/wedge bonding of AlSi1 wires

The wedge microstructure of AlSi1 wire bonds as well as the interface between the bonding wire and the Cu/Ni/Au metallization layer especially for chip on board (COB) assemblies was investigated by focused ion beam (FIB), transmission electron microscopy (TEM), and microhardness measurements. The as-received wires were characterized by fiber texture of 〈111〉 and 〈100〉 orientation. With increasing ultrasonic (US) power, the results indicate recrystallization of the grain structure and decreasing microhardness inside the bonded wedge contacts. The interface between the AlSi1 wire and the Cu/Ni/flash-Au metallization layer of the optimized bonds consists of a closed crystalline Au layer. Above this Au layer, a second zone consisting of intermetallic phases was analyzed and identified by electron diffraction as Au₈Al₃.     

Long-term thermal stability of Ti/Al/Mo/Au ohmic contacts on n-GaN

Improved performance of the ohmic contacts on n-GaN has been demonstrated with the use of MoAu as the capping layer on TiAl metallization. Contact resistance as low as 0.13 Θ-mm was achieved in these ohmic contacts when annealed at 850°C for 30 sec. We have studied the long-term thermal stability of these contacts at 500°C, 600°C, 750°C, and 850°C, respectively. The Ti/Al/Mo/Au metallization forms low contact-resistance ohmic contacts on n-GaN that are stable at 500°C and 600°C after 25 h of thermal treatment. The ohmic-contact performance degrades after 10 h of thermal treatment at 750°C, while the contacts exhibit nonlinear current-voltage (I-V) characteristics after 1 h of thermal treatment at 850°C with the formation of oxide on the surface of the contacts accompanied by surface discoloration. The intermetallic reactions taking place in the contacts during the long-term thermal treatments were studied using Auger electron spectroscopy (AES), and the surface morphology was characterized using atomic force microscopy (AFM).     

SiC Die Attach for High-Temperature Applications

Eutectic solders AuIn19 and AuGe12 and nanosilver paste were investigated for SiC die attach in high-temperature (300°C) applications. The soldering or sintering conditions were optimized through die shear tests performed at room temperature. In particular, application of static pressure (3.5 MPa) during sintering resulted in greatly improved mechanical behavior of the nanosilver-based joint. Microstructural study of the eutectic solders showed formation of Au-rich grains in AuGe die attach and significant diffusion of Au and In through the Ni layer in AuIn19 die attach, which could lead to formation of intermetallic compounds. Die shear tests versus temperature showed that the behaviors of the studied die attaches are different; nevertheless they present suitable shear strengths required for high-temperature applications. The mechanical behavior of joints under various levels of thermal and mechanical stress was also studied. Creep experiments were carried out on the eutectic solders to describe the thermomechanical behavior of the complete module; only one creep mechanism was observed in the working range.     

AlGaN/GaN HEMT欧姆接触的研究进展

从欧姆接触形成的机理出发,介绍了在AlGaN/GaN HEMT中实现源和漏区欧姆接触的各种方法,如表面处理技术、金属化系统和重掺杂技术等.回顾了近年来这些方法的研究进展.     

Feature Size Limit of Liftoff Metallization Technology

The feature size limits for liftoff metallization technology are evaluated both experimentally and by computer simulation following Blech's model. The mechanism producing a smoothly sloped metallization pattern profile was also clarified. The simulation reveals that the average slope angle of the metallization pattern sidewalls is determined by the reverse mask topology, metallization thickness, and the maximum incident angle of the evaporation system used for the metallization deposition. Simulation results showed good coincidence with experimental results. It is shown that the average slope angle can be controlled between 20/spl deg/and 70/spl deg/ with polyimide liftoff technology. Feature size limit, i.e., the minimum pitch of metallization patterns, is determined by the reverse mask topology and the maximum incident angle as well as by mechanical and chemical properties of the polyimide layer, but is independent of metallization thickness. In a sample application of the technology in the fabrication of interconnections on rugged LSI surfaces, the minimum pitch of the polyimide liftoff metallization patterns was estirriated to be 2.6 /spl mu/m.     

Effects of metallization characteristics on gold wire bondability of organic printed circuit boards

Organic printed circuit boards (PCBs) with Au/Ni plates on bond pads are widely used in chip-on-board (COB), ball grid array (BGA), and chip-scale packages. These packages are interconnected using thermosonic gold wire bonding. The wire bond yield relies on the bondability of the Ni/Au pads. Several metallization parameters, including elemental composition, thickness, hardness, roughness, and surface contamination, affect the success of the solid state joining process. In this study, various characterization and mechanical testing techniques are employed to evaluate these parameters for different metallization schemes with varying Ni and Au layer thicknesses. The pull force of Au wires is measured as a function of plasma treatment applied before wire bonding to clean the bond pads. Close correlations are established between metallization characteristics and wire bond quality.