金硅共晶键合在微机械Golay-cell红外探测器中的应用

利用硅微机械加工技术制备微机械Golay-cell红外探测器硅可动敏感薄膜,探测器气室由带薄膜结构硅片与带孔结构硅片键合密闭形成,气室中敏感气体吸收红外辐射而膨胀,使硅膜产生形变,借助硅膜电极板与金属电极板形成的平行板电容反映该形变变化量.运用Si/Ti/Au/Au/Ti/Si实现对探测器的金/硅共晶键合封装,形成气室,制备出探测器样品并初步得到响应.该键合方法能够进行选择区域键合,实验证明键合强度达到体硅强度.     

变组分变掺杂p-i-n型AlGaAs/GaAs微结构中子探测器性能表征

制备了一种在p-i-n型AlGaAs/GaAs材料上刻蚀微沟槽的中子探测器。通过MOCVD技术生长了变组分变掺杂的p-i-n型AlGaAs/GaAs，使用ICP技术在材料上刻出微沟槽，沟槽宽度为25μm，深度为10μm。探测器的探测面积为4 mm2，沟槽宽度和间距为1∶1，呈周期性排列，在沟槽中填充中子转换材料探测热中子信号。通过对平面和微结构p-i-n型AlGaAs/GaAs探测器的电学特性、α粒子以及中子探测性能的比较分析，发现两者在电学特性和α粒子能量分辨率方面有较大差别。5 V偏压下平面型和微结构AlGaAs/GaAs探测器的漏电流分别是-0.024 1μA、-0.627μA，两者相差近30倍，这是由于微结构刻蚀了部分异质结导致器件表面漏电流增加。0 V偏压下微结构探测器α粒子能量分辨率比平面型也有些许恶化，但在热中子探测上微结构效果更佳，中子总计数微结构比平面型多一倍。微结构降低了探测器的自吸收问题，同时增大了探测器的中子接触面积，在热中子探测上应用前景广阔。     

微硅加速度计中静电键合封接技术的应用

在微硅加速度计的研制中,静电键合具有传统胶接技术所无法比拟的优点,是目前该加速度计研制中广泛应用的粘接技术。叙述了静电键合技术的机理和它在微硅加速度计装配中的具体工艺流程,指明了技术的关键之处,并分析了该技术的优缺点,提出了进一步改进的方案。     

室温辐射探测器用CdZnTe晶体生长及其器件制备

采用改进的垂直布里奇曼法生长了直径为60 mm的碲锌镉晶体,晶体利用率达到70%以上。晶体中Te沉淀/夹杂密度小于1×10-3cm2,电阻率达到4×1010Ω.cm。利用得到的晶体制备了平面型单元探测器,测量了对不同能量射线的分辨率,其中对241Amγ能谱的分辨率达到4.7%,对137Cs能谱的分辨率为4.2%。采用Hecht公式对探测器收集效率与偏压的关系进行了拟合,得到电子的迁移率与寿命乘积值达到2.3×10-3cm2/V。     

基于SiPM的线阵式X射线背散射探测器设计与性能评估

为了实现现场快速安全检查过程中敏感物质的细分,探讨了一种通过X射线背散射信号求取物质密度的方法,并完成了实现该方法的核心部件——一种基于硅光电倍增管（SiPM）的的线阵式闪烁体探测器的设计和功能验证。该探测器具有能量分辨的能力,能够分析不同物质在不同能量下的散射衰减。在环境温度-10℃～50℃条件下,该探测器输出的脉冲幅值稳定,能量分辨率在221%～257%变化（室温条件时能量分辨率为236%@595 KeV）。其线阵的结构为实现散射与透视图像空间上的一一对应,进而实现散射信息与透视信息的融合打下了基础。不同材料的散射能谱测量结果表明,该探测器所探测的能量曲线能够反映物质的密度特性,验证了其用于散射能谱探测以实现物质分类的可行性,在现场查缉装备的智能识别方面极具应用前景。     

表面处理对碳化硅直接键合的影响研究

SiC的直接键合对于许多应用于高温环境的MEMS微器件有着非常重要的应用价值,但是晶片的表面处理是影响SiC直接键合的关键因素。设计中采用改进后的湿法清洗方法和等离子体处理对晶片表面进行处理;从而得到满足直接键合的洁净度和粗糙度。最后利用热压法实现了SiC的直接键合,并且估计其键合能为14.47 MPa。     

MEMS封装中阳极键合技术的影响因素研究和设计因素分析

结合MEMS气密性封装的需要,以玻璃与硅晶片阳极键合为例,给出阳极键合的封装工艺,从键合机理的角度研究了玻璃与硅阳极键合的影响因素,并就玻璃与硅阳极键合的设计因素做了分析,得到直径为100mm的Pyrex7740玻璃晶片和硅晶片在键合温度为500℃时,硅晶片的径向应力σrr=134.29MPa;键合后晶片的径向膨胀μ=0.1274mm。     

面向即时检测芯片超声波精密键合的熔接结构及工艺参数

针对芯片即时检测(POCT)芯片对键合精度、键合强度、生产效率和生物兼容性的要求,基于超声波键合技术设计了结构化的导能筋布置形式和阻熔导能接头结构。研究了超声波键合时间和键合压力对微通道高度保持性能的影响,确定了精密超声波键合工艺参数。利用高精度显微镜、拉伸试验机和羊全血分别对键合后芯片的微通道高度、键合强度、微通道密闭性以及液体自驱动性能进行了测试。结果表明:所设计的导能筋布置形式合理可靠;利于芯片各功能的集成,阻熔导能接头结构能够较精确地控制键合后微通道的高度,键合精度达到2μm;全血驱动时间的极差在20s以内;所确定的键合工艺参数能够实现高强度的键合,键合强度不小于2.5 MPa。该熔接结构及工艺参数具有键合精度高、键合强度高、生物兼容性好和熔接均匀等优点,可应用于医用POCT芯片产品中。     

键合技术在微机械Golay-cell红外探测器中的应用

介绍多种硅片键合技术及其在基于高菜盒（Golay-cell）原理的微机械红外探测器中的应用。对多种键合方法在该器件中的实验结果进行比较，确定了现阶段最优的键合方法，即采用局部电场屏蔽方法的阳极键合方法，键合成功率在90％以上，并初步实现了器件的标准化制作。     

微力学测试仪在MEMS键合强度测试中的应用

研制微力学测试仪,对微电子机械系统中键合结构的强度进行测试。最大载荷为1．4N,在载荷量程为450mN时仪器的最高分辨力为10μN。采用键合在玻璃基底上的硅悬臂梁作为试样。为模拟横力剪切破坏和扭转破坏工况,用微力学测试仪分别在悬臂梁的固定端和自由端施加载荷至试样破坏。测得相应的破坏载荷并计算出最大剪应力。对破坏残骸的显微观察发现,存在玻璃开裂和硅开裂2种失效模式。该技术为微电子机械系统(micro-electro-mechanical system,MEMS)键合结构的强度表征提供一种有效方法,并可用来进行微悬臂梁或微桥的强度测试。     

Laboratory nuclear-physics methods for determining the characteristics of charged particle silicon detectors

A review is presented of “nontraditional” laboratory nuclear-physical methods for determining key parameters of charged-particle semiconductor detectors, such as the sensitive depth and the energy resolution. The methods for measuring the sensitive depth are based on the peculiarities in interactions of radiation from standard α,β, and γ sources and monochromatic neutrons with the detector materials and require that several “reference” detectors with known characteristics be available. Using the proposed methods, it is possible to preliminarily estimate the serviceability of detectors before employing them in expensive experiments, e.g., on accelerator beams.     

Large-volume HPGe detectors for rare events with a low deposited energy

The manufacturing technique and the main characteristics of large-volume HPGe detectors with a capacitance of ∼0.5 pF are described. Based on the developed technique, it is possible to produce a detector such that it is comparable in mass to a coaxial HPGe detector, but its energy resolution and detection threshold are close to the values characteristic of small X-ray HPGe detectors.     

A photoelectron-photoion coincidence imaging apparatus for femtosecond time-resolved molecular dynamics with electron time-of-flight resolution of sigma=18 ps and energy resolution Delta E/E=3.5%

We report on the construction and performance of a novel photoelectron-photoion coincidence machine in our laboratory in Amsterdam to measure the full three-dimensional momentum distribution of correlated electrons and ions in femtosecond time-resolved molecular beam experiments. We implemented sets of open electron and ion lenses to time stretch and velocity map the charged particles. Time switched voltages are operated on the particle lenses to enable optimal electric field strengths for velocity map focusing conditions of electrons and ions separately. The position and time sensitive detectors employ microchannel plates (MCPs) in front of delay line detectors. A special effort was made to obtain the time-of-flight (TOF) of the electrons at high temporal resolution using small pore (5 microm) MCPs and implementing fast timing electronics. We measured the TOF distribution of the electrons under our typical coincidence field strengths with a temporal resolution down to sigma=18 ps. We observed that our electron coincidence detector has a timing resolution better than sigma=16 ps, which is mainly determined by the residual transit time spread of the MCPs. The typical electron energy resolution appears to be nearly laser bandwidth limited with a relative resolution of DeltaE(FWHM)/E=3.5% for electrons with kinetic energy near 2 eV. The mass resolution of the ion detector for ions measured in coincidence with electrons is about Deltam(FWHM)/m=14150. The velocity map focusing of our extended source volume of particles, due to the overlap of the molecular beam with the laser beams, results in a parent ion spot on our detector focused down to sigma=115 microm.     

Square-Wave Operation of a Thermal Conductivity Detectort†

SUMMARY

Equipment is described for the operation of thermal conductivity detectors with square-wave bridge current. The resulting ac output signal allows amplification without the need for low-level choppers. With phase-locked demodulation of the amplified signal, bridge unbalance signals of the order of 10 nV can be detected. This performance exceeds the requirements of presently available detector cells, which produce noise levels of the order of 100 nV.

The instrument is compatible with most existing hot wire detectors and may be used with economical recorders. Air and other permanent gases can be reliably analyzed at levels of 0.02 μl, with detection limits of the order of 0.002 μl. This performance makes the instrument attractive in the field of air pollution and opens the way to further research in the design of low-noise detector cells.     

The use of a segmented cathode of a drift tube for designing a track detector with a high rate capability

Detector rate capability is one of the main parameters for designing a new detector for high energy physics due to the permanent rise of the beam luminosity of modern accelerators. One of the widely used detectors for particle track reconstruction is a straw-detector based on drift tubes. The rate capability of such detectors is limited by the parameters of readout electronics. The traditional method of increasing detector rate capability consists in increasing their granularity (the number of “elementary” detectors = readout channels) by reducing the straw diameter and/or by dividing the straw anode wire into two parts (for decreasing the rate per readout channel). A new method of designing straw detectors with a high rate capability is presented and tested. The method is based on dividing the straw cathode into parts and the independent readout of each part.     

Determining the Characteristics of Cosmic-Radiation Nuclei in the Sileye Experiment on Board the Mir Orbital Station

An algorithm for reconstructing the characteristics (charge, mass, and energy) of cosmic-radiation nuclei with 20- to 200-MeV/nucleon energies is described. The detector is a telescope of three two-coordinate planes with two 1-mm-thick iron filters inserted between them. Each plane is composed of two strip silicon detectors with 3.6-mm-wide orthogonally oriented strips, an effective area of 6 × 6 cm², and a thickness of 380 m. The algorithm for reconstructing the nuclei characteristics is based on the analysis of how the specific ionization losses change as the nuclei pass through the filter material. The results of the Monte Carlo simulation are presented for the energy dependence of the telescope acceptance and the energy deposited in the detectors by different nuclei in view of the detector calibration on the nuclear beams of the accelerator. The mass resolution of the telescope is 30, 12, and 5% for He, N, and Al nuclei, respectively. The energy resolution, which is 20%, is much the same for all nuclei.     

Detection of nanosecond-scale, high power THz pulses with a field effect transistor

We demonstrate detection and resolution of high power, 34 ns free electron laser pulses using a rectifying field effect transistor. The detector remains linear up to an input power of 11 ± 0.5 W at a pulse energy of 20 ± 1 μJ at 240 GHz. We compare its performance to a protected Schottky diode, finding a shorter intrinsic time constant. The damage threshold is estimated to be a few 100 W. The detector is, therefore, well-suited for characterizing high power THz pulses. We further demonstrate that the same detector can be used to detect low power continuous-wave THz signals with a post detection limited noise floor of 3.1 μW/√Hz. Such ultrafast, high power detectors are important tools for high power and high energy THz facilities such as free electron lasers.     

Using induced signals to sense position from a microchannel plate detector

We demonstrate a novel concept for a position sensitive microchannel plate detector. This detector provides sub-millimeter spatial resolution by examining the signal induced on a wire harp by the electron cloud from a microchannel plate detector. Wires in the harp are efficiently read out by coupling them to a delay line.     

ZSX100e型X射线荧光光谱仪真空系统故障的诊断方法

本文较全面的概括了ZSX100e型X射线荧光光谱仪真空系统的故障,并分析了故障原因。根据仪器分光室、样品准备室的真空系统工作原理和交互过程,从真空泵使用及性能判断、分光室和样品准备室的密封部件、探测器工作气体气路、探测器窗膜、自动芯线清洗装置、气体密度稳定器等几个方面归纳出不同情况下仪器真空系统故障的诊断方法。     

Note: a high performance pulse energy detector for Q-switched laser based on photoacoustic effect

A high performance pulse energy detector is developed based on photoacoustic effect. Different from the detectors reported before which also utilized photoacoustic effect, our detector can measure the energy of each pulse output from a Q-switched laser and monitor the pulse energy fluctuation in real time owing to the signal processing circuit designed. By comparing with a commercial laser energy meter, our detector is proved to be of high sensitivity and accuracy. We test the detector under illumination of different pulse energy at varied wavelengths, and the results demonstrate that the detector has a broad spectral response and a dynamical energy range. Besides, the measurements of this detector will not be affected by the background light according to the principle of photoacoustic effect.