半导体四探针测试仪新型恒流源的开发

首先根据四探针测试理论,阐述了恒流源电路在四探针测试仪中的重要性,给出了对恒流源的基本要求。然后介绍了我们在开发前期实验过的2种恒流源电路,它们分别是级联型镜象电流源电路和电压-电流转换电路。最后介绍了我们实际采用的直接利用反馈运放输出恒流的电路。对每种电路都给出了原理图、电流计算公式和性能分析。     

非侵入式脉搏血氧检测系统设计

氧气是新陈代谢的基础,血氧饱和度作为一项重要的健康指标,在临床医学以及家庭保健等方面有着广泛的应用前景。本文以TI的超低功耗的MSP430微处理器作为系统的核心,设计了一款基于数字血氧探头的脉搏血氧检测系统,并实现了基于VC的下位机与上位机的串行通信。数字信号处理方案简化了电路设计,实验结果证实本方案能够有效降低成本、减少开发板的面积,从而更好的满足市场需求。     

用二次离子质谱和扩展电阻探针技术测量硅中注入硼的深度分布及扩展电阻探针技术分辨率的估算

利用二次离子质谱和扩展电阻探针技术测量了硅中注入硼的深度分布 .在适当的测量深度 ,用扩展电阻探针技术测得的结果对二次离子质谱技术测量的结果进行了标定 ,从而得到硅片中硼原子的深度分布 .用近似模型估算了扩展电阻探针针尖半径对测试分辨率的影响 .若探针针尖半径为r0 ,测量斜面的角度为 ξ ,在用扩展电阻探针技术测量载流子浓度的深度分布时 ,可以近似认为深度分辨率为 7 86r0 sinξ.还定性讨论了样品表面耗尽层对扩展电阻探针技术的影响.     

测量材料吸收毫米波性能的新型探头

提出了用于测量吸波材料吸收雷达波性能的新型探头。引入高次模,采用相位分析法,克服了多变量干扰,简化计算。在固定区间求偏差和方差最小值,得到平缓电场。仿真结果证明新型探头口径电场平缓,波动小,近似平面波。新型探头的平面波范围与口径比为53%,比现有厘米波探头扩大了17.2%,能精确地模拟雷达对材料的辐射,减小测量误差。此探头尺寸较小,可广泛应用于户外测量材料吸收毫米波雷达电磁波的性能。     

Atom probe tomography of Ni silicides: First stages of reaction and redistribution of Pt

The silicide formation and the redistribution of Pt after deposition and after a heat treatment at 290 °C of Ni_1−xPt_x films on Si have been analysed by atom probe tomography assisted by femtosecond laser pulses. Two phases with different composition were found to form during deposition at room temperature: a NiSi layer with a relatively constant thickness of approximately 2 nm and a particle of Ni₂Si. The shape of the Ni₂Si particle is in accordance with nucleation followed by lateral growth formation. After heat treatment, two silicide phases Ni₂Si and NiSi were found together with the Ni_1−xPt_x solid solution. The redistribution of Pt at the Ni_1−xPt_x/Ni₂Si interface is a clear illustration of the snowplow effect. A segregation of Pt at the Ni₂Si/NiSi interface has been observed and is attributed to interfacial segregation. The effect of the redistribution of Pt on the silicide formation is discussed.     

基于表面增强拉曼光谱的光纤生化传感器

基于生化分子检测技术高灵敏度、小型化的需求,通过简单的管式腐蚀法制成一种锥柱组合型光纤探针,并通过相反的静电引力将银纳米颗粒结合到硅烷化的二氧化硅光纤探针表面。用罗丹明6G（R6G）溶液的检测极限来表征该光纤探针的活性和灵敏度,通过优化银纳米颗粒的自组装时间为30mins、光纤探针直径为62μm,制备出高灵敏度的光纤表面增强拉曼散射探针,远端检测R6G的检测极限可达到10-14Mol/L,银纳米颗粒的增强因子为1.36×104。因此,该光纤表面增强拉曼散射探针在分子检测方面有巨大的应用前景。     

Four-point probe characterization of 4H silicon carbide

We report on four-point probe measurements on SiC wafers as such measurements give erratic data. Current-voltage measurements on n-type SiC wafers doped to 3 × 10¹⁸ cm⁻³ are non-linear and single probe I-V measurements are symmetrical for positive and negative voltages. For comparison, similar measurements of p-type Si doped to 5 × 10¹⁴ cm⁻³ gave linear I-V, well-defined sheet resistance and the single probe I-V curves were asymmetrical indicating typical Schottky diode behavior. We believe that the reason for the non-linearity in four-point probe measurements on SiC is the high contact resistance. Calculations predict the contact resistance of SiC to be approximately 10¹² Ω which is of the order of the input resistance of the voltmeter in our four-point probe measurements. There was almost no change in two-probe I-V curves when the spacing between the probes was changed from 1 mm to 2 cm, further supporting the idea that the I-V characteristics are dominated by the contact resistance.     

电子探针在中药滑石质量检验中的应用

滑石是一种十分重要的中药矿物药,其质量检验对于人体健康和环境至关重要。本文提出的以电子探针为主、并辅以X光衍射分析等方法的滑石质量检验途径,是一次新的探索。正是由于电子探针可以同时进行高倍图像观察和定性定量分析,对滑石中的杂质分析灵敏度更好,其检测结果也更直观易懂。     

LTCC基片的飞针测试工艺研究

低温共烧陶瓷技术(Low Temperature Co-fired Ceramic LTCC)是近年来兴起的一种相当令人瞩目的多学科交叉的整合组件技术,广泛用于基板、封装及微波器件等领域。主要介绍当前广泛用于检测混合电路板、LTCC陶瓷基板、PCB裸板故障的飞针测试设备在陶瓷基片测试中的工艺研究。     

Anti-buckling S-shaped vertical microprobes with branch springs

We propose the S-shaped vertical probes with branch springs for the wafer-level testing of IC chips. The conventional S-shaped vertical probe requires a guide structure to prevent buckling due to the large overdrive actuation involved. However, the guide structure not only increases the cost of fabrication, but it also requires a troublesome assembly procedure. In this paper, we present the S-shaped vertical probe with branch springs on the left and right sides of the main spring to prevent buckling. This probe was designed using finite-element methods and fabricated using Ni-Co electroplating. The performances of the probe for the wafer-level testing of IC chips were measured with the probe test equipments. Compared to the identical conventional S-shaped probe, the proposed probe has the overdrive (60 μm) that is 1.2 times larger and the contact force (25 mN) that is 2.5 times larger. This new S-shaped vertical probe satisfies the design requirements for a vertical probe without the guide structure and has the potential for use as a cost-effective guide-free probe card for the wafer-level testing of IC chips.