一种快速响应的压电晶体生物亲和传感器

在６ＭＨｚ的压电晶振ＱＣＭ（ｑｕａｒｔｚｃｒｙｓｔａｌｍｉｃｒｏｂａｌａｎｃｅ）金电极表面采用蛋白质Ａ－金的方法固定生物敏感膜，利用ＱＣＭ单面测试技术和连续流动自动分析系统全面测试此膜与人体免疫球蛋白Ｇ（ＩｇＧ）之间的生物亲和反应，从而研究快速响应的压电晶体生物亲和传感器，停止流动注测量时结果为：在１－２ｍｉｎ内亲和响应时间而急剧增大，随后趋于缓慢，对１０７μｇ／ｍｌ人体ＩｇＧ三次响应的标准偏差及     

硅单晶加工工艺与质量关系的讨论

随着电子工业的迅速发展,对电路的集成度要求愈来愈高。集成电路的电学性能对硅衬底片表面状态是十分敏感的,为获取最佳硅表面状态,从单晶硅到抛光片的完成所涉及到的工艺以及它们之间相互关系进行研究和讨论,来满足电子工业对硅衬底片质量的要求。本文将对单晶硅在加工过程中所涉及的工艺与质量之间的关系进行详细论述。     

家兔免疫伊氏锥虫弱毒疫苗后的T细胞,IgG和IgM动态变化

分别以3Ｈ—ＴｄＲ掺入的淋巴细胞转化反应和ＢＡ—ＥＬＩＳＡ方法检测家兔免疫后及攻虫后Ｔ细胞及特异性抗体ＩｇＧ和ＩｇＭ的动态变化。发现免疫后家兔外周血Ｔ淋巴细胞增殖反应于２４ｄ达到高峰，第３１天开始迅速降低。攻虫后特异性Ｔ细胞增殖反应强度未见升高，而特异性抗体Ｉｇｈ、ＩｇＭ均于第２１天达到高峰，攻虫后ＩｇＧ、ＩｇＭ分别在第６天和第９天又达到高峰。结果表明，在这种抗锥虫免疫中Ｔ细胞没有起主导作用，而特异性抗体ＩｇＧ和ＩｇＭ起主导作用。     

蛋白A修饰的压电晶体检测器测量人血清中免疫球蛋白G的研究

以蛋白Ａ修饰的压电晶体测量人血清中免疫球蛋白Ｇ为研究内容，比较了三种膜对人ＩｇＧ结合的特异性，探索了传感器再利用的方法。     

微创手术式硅微机械加工（MISSM）技术

介绍了一种新颖的微创手术式硅微机械加工(MISSM)技术,该技术充分利用(111)硅片的晶向分布和各向异性湿法腐蚀的特性。通过在单晶硅片表面制作一系列微型释放窗口来定义结构的轮廓及尺寸,实现在单晶硅片内部选择性可自停止腐蚀技术,制作出不同结构尺寸的腔体。同时,结合不同器件结构设计的需求,缝合微型释放窗口并进行后续工艺制作及最终可动结构释放。该技术采用微创手术式单硅片单面体硅工艺替代传统的表面微机械工艺,制作工艺简单,既具有单硅片单面加工的优势又便于与IC工艺兼容。文章详细讲述了微创手术式三维微机械结构的成型机理和工艺流程,并针对其关键技术进行了系统的分析,取得了令人满意的结果。     

电化学DNA传感器中DNA的固定与杂交条件探讨

利用自组装单分子膜法,将人工合成的乙肝病毒单链DNA片断作为特异性探针固定在金电极表面,结合电活性指示剂Hoechst33258构成DNA电化学传感器。在乙肝特异性DNA探针的自组装固定过程中,探讨了自组装单分子膜的成膜条件,总结出在探针浓度为100mg/L,自组装固定时间为12h对DNA探针的固定较为有利。考察了单链DNA修饰电极的伏安特性和单链DNA修饰电极的电子传递性能。在对标准互补DNA溶液的杂交检测过程中,探讨了杂交时间、杂交温度、指示剂的作用时间等对DNA传感器检测的影响。当杂交时间为90min,杂交温度为25℃,杂交溶液中NaCl浓度为0.3mol/L时,指示剂的伏安信号较好。     

一种验证SPR传感器金膜表面固定蛋白质分子有效性的简易途径

利用表面等离子共振传感器进行免疫检测的实验中,需要在化学性质稳定的金膜表面固定蛋白质分子探针。如何验证一种方法是否能够成功固定蛋白质分子具有非常重要的现实意义。提出的验证方法采用酶反应作为标志,如果某种方法确实能有效固定蛋白质分子,那么它也能固定酶。将固定好酶的金膜浸入相应的底物溶液中发生变色反应,测量底物溶液的吸收光谱,即可根据结果判断是否有效固定了酶,同时达到判断这种方法是否可固定蛋白质的目的。具有快速、方便、低成本等优点。采用经过验证的方法固定抗IgG后通入IgG,实验响应良好。     

基于双正交提升小波的单晶硅绒面的去噪研究

单晶硅绒面在制绒时随着制绒液的浓度的变化,有可能会导致腐蚀不均匀,绒面的顶部或底部会有准方形的凹坑出现。基于双正交小波,结合提升小波的优点,形成双正交提升小波,对单晶硅绒面进行去噪处理。结果表明,双正交提升小波能将表面的"凹坑"缺陷去除,并以光的吸收率为依据将"凹坑信号"等价为"小的三角形"。     

SO I 单晶硅压力传感器模拟计算与优化设计

利用有限元分析方法，借助ANSYS软件，对SOI单晶硅压力传感器进行一系列的分析和计算机模拟，探讨了传感器应变膜在固定宽度或固定面积条件下，宽长比对理论输出的影响，以及应变膜厚度对理论输出的影响，给出了设计应变膜的优化方案；并对根据模拟结果首次制作的SOI单晶硅压力传感器进行了测量，结果与理论值符合得较好。     

凝集液相压电免疫传感器用于人血清中IgG的测定

分别讨论了ＰＥＧ,ＣＭＣ和ＰＡＭ为介质的三种聚合物凝集液相ＩｇＧ压电免疫分析法,详细考察了各聚合物浓度及分子量,抗体稀释度,ＰＢＳ浓度,聚合物－ＤＳ复合时间和反应温度等实验条件对频移的影响。上述三种聚合物为介质时,压电免疫传感器方法对浓度范围分别在２．０－３９．０μｇ／ｍｌ,０－２４．０μｇ／ｍｌ和０－２０．６μｇ／ｍｌ内的ＩｇＧ可进行准确测定。     

High temperature resistant antireflective moth-eye structures for infrared radiation sensors

The Fresnel reflections occurring at the interfaces of a silicon wafer shall be drastically reduced by reactive ion beam etching of so called moth-eye structures into both surfaces of the wafer. This kind of impedance matching is advantageous to a multilayer interference system when the silicon wafer shall be used as an entrance window for high temperature thermopile infrared radiation sensors and emitters. The transmission was measured to be increased by more then 60%, compared to a polished silicon wafer.The authors wish to thank Dr. Albrecht Lerm, and Jürgen Müller, Institute for Physical High Technology, for their advice making these investigations.     

Femtosecond laser-induced silicon surface morphology in water confinement

This article investigates the use of femtosecond laser induced surface morphology on silicon wafer surface in water confinement. Unlike irradiation of silicon surfaces in the air, there are no laser induced periodic structures, but irregular roughness is formed when the silicon wafer is ablated under water. The unique discovery of a smoothly processed silicon surface in water confinement under certain laser parameter combinations may help improve laser direct micromachining surface quality in industrial applications.     

Fabrication of a high aspect ratio nanoporous array on silicon

In this study, a simple method for the fabrication of high aspect ratio silicon nanoporous arrays is developed. A N-type silicon wafer is used as the substrate material. A micro-scale pattern of the desired porous array is transferred to the front surface of the silicon wafer by photolithography after which the wafer is placed in a home-made fixture to efficiently expel the etching generated air and promptly hold the back-side illumination light. A halogen lamp is used as the light source for backside illumination to enhance the electron–hole pair generation. An anodization process is then carried out using a new etchant consisting of hydrofluoric acid and mixed EtOH and EMSO surfactant to effectively polish the pore surfaces and sharpen the tips of the etched pores. A nanochannel array with a nano-tip of 61.4?nm is obtained.     

Diagnostic techniques for the dynamics of a thin liquid film under forced flow and evaporating conditions

Motivated by quantification of micro-hydrodynamics of a thin liquid film which is present in industrial processes, such as spray cooling, heating (e.g., boiling with the macrolayer and the microlayer), coating, cleaning, and lubrication, we use micro-conductive probes and confocal optical sensors to measure the thickness and dynamic characteristics of a liquid film on a silicon wafer surface with or without heating. The simultaneous measurement on the same liquid film shows that the two techniques are in a good agreement with respect to accuracy, but the optical sensors have a much higher acquisition rate up to 30 kHz which is more suitable for rapid process. The optical sensors are therefore used to measure the instantaneous film thickness in an isothermal flow over a silicon wafer, obtaining the film thickness profile and the interfacial wave. The dynamic thickness of an evaporating film on a horizontal silicon wafer surface is also recorded by the optical sensor for the first time. The results indicate that the critical thickness initiating film instability on the silicon wafer is around 84 μm at heat flux of ~56 kW/m². In general, the tests performed show that the confocal optical sensor is capable of measuring liquid film dynamics at various conditions, while the micro-conductive probe can be used to calibrate the optical sensor by simultaneous measurement of a film under quasi-steady state. The micro-experimental methods provide the solid platform for further investigation of the liquid film dynamics affected by physicochemical properties of the liquid and surfaces as well as thermal-hydraulic conditions.     

Investigation of attractive forces between PECVD silicon nitride microstructures and an oxidized silicon substrate

A troublesome phenomenon encountered during the realization of free-standing microstructures, for example, beams, diaphragms and micromotors, is that initially released structures afterwards stick to the substrate. This effect may occur during wafer drying after the etching process has been completed, as well as during normal operation as soon as released structures come into contact with the substrate. In this paper the most important types of attractive forces are discussed with respect to their possible influence on the performance of micromachined structures. It is concluded that the main reason for sticking of PECVD silicon nitride micromachined structures is adsorption of water molecules. The water molecules, adsorbed on both surfaces, attract each other as soon as the surfaces come into contact. It is shown that a chemical surface modification, in order to achieve hydrophobic surfaces, is an effective method for avoiding adsorption of water, and therefore reduces sticking. Sticking of micromachined structures during drying is reduced by rinsing with a non-polar liquid before wafer drying.     

Discussion of tooling solutions for the direct bonding of silicon wafers

Silicon-to-silicon fusion (or direct) pre-bonding is an important enabling technology for many emerging microelectronics and MEMS technologies. A silicon–silicon direct bond can be easily formed, where the wafer surfaces are highly flat and very clean (Tong and Gosele), however for practical structured MEMS devices, wafer bow and local roughness may be compromised such that it is no longer a trivial task to achieve a direct bond. Tooling has been developed to facilitate the in situ alignment and bonding of silicon-to-silicon wafers in a vacuum chamber. The rate and direction of the bond propagation are controlled, thus minimising the occurrence of non-particle related voids. The tooling system also allows wafers with “non-ideal” surfaces or warped profiles to be bonded, by maximising the area across which bonding occurs and providing in situ annealing. The ability to anneal the wafers while maintaining clamping force creates attractive forces high enough to overcome the mechanical repulsive forces between the wafers and maintain a permanent bond. The tooling system can also be configured to give control over the bow or residual stress in the bonded pair, a factor that is critical in multi-stack direct wafer bonding.     

InP dies transferred onto silicon substrate for optical interconnects application

We bonded quantum well InP dies on a photonic layer transferred on silicon CMOS processed wafer using direct molecular bonding. This approach is suitable for new applications, viz., photonics on silicon, 3D packaging and integrated sensors. The chips are diced from a bulk substrate and bonded directly onto a silicon substrate without any organic nor metallic adhesive layer. A thin silicon dioxide layer can be added on both assembled surfaces to enhance bonding quality. After bonding, the dies can mechanically be thinned down to 20 μm and chemically etched. The InAsP quantum well stack of the InP dies keeps its optoelectronics features and performances after being transferred onto a silicon substrate.     

Stamp-and-stick room-temperature bonding technique for microdevices

Multilayer MEMS and microfluidic designs using diverse materials demand separate fabrication of device components followed by assembly to make the final device. Structural and moving components, labile bio-molecules, fluids and temperature-sensitive materials place special restrictions on the bonding processes that can be used for assembly of MEMS devices. We describe a room temperature "stamp and stick (SAS)" transfer bonding technique for silicon, glass and nitride surfaces using a UV curable adhesive. Alternatively, poly(dimethylsiloxane) (PDMS) can also be used as the adhesive; this is particularly useful for bonding PDMS devices. A thin layer of adhesive is first spun on a flat wafer. This adhesive layer is then selectively transferred to the device chip from the wafer using a stamping process. The device chip can then be aligned and bonded to other chips/wafers. This bonding process is conformal and works even on surfaces with uneven topography. This aspect is especially relevant to microfluidics, where good sealing can be difficult to obtain with channels on uneven surfaces. Burst pressure tests suggest that wafer bonds using the UV curable adhesive could withstand pressures of 700 kPa (7 atmospheres); those with PDMS could withstand 200 to 700 kPa (2-7 atmospheres) depending on the geometry and configuration of the device.     

Low temperature silicon direct bonding for application in micromechanics: bonding energies for different combinations of oxides

Plain or structured hydrophillic silicon wafers covered with native oxide or with thermally grown oxide layers have been directly bonded at room temperature; afterwards, the samples were annealed at 100°C to 400°C. There is a significant difference in the observed bonding energy depending on the wafer pairing chosen. If one or both wafers are covered with a native oxide layer, high bonding strengths are reached even at low temperatures. This can be explained by the different diffusion behaviour of water molecules through a thick thermal oxide layer on one hand, and through a thin native oxide layer on the other hand. Two different methods for the activation of the wafer surfaces just prior to bonding are described.     

Fabrication of silicon and oxide membranes over cavities usingion-cut layer transfer

Silicon and oxide membranes were fabricated using an ion-cut layer transfer process, which is suitable for sub-micron-thick membrane fabrication with good thickness uniformity and surface micro-roughness. After hydrogen ions were implanted into a silicon wafer, the implanted wafer was bonded to another wafer that has patterned cavities of various shapes and sizes. The bonded pair was then heated until hydrogen-induced silicon layer cleavage occurred along the implanted hydrogen peak concentration, resulting in the transfer of the silicon layer from one wafer to the other. Using this technique, we have been able to form sealed cavities and channels of various shapes and sizes up to 50-μm wide, with a 1.6-μm-thick silicon membrane. As a process variation, we have also fabricated silicon dioxide membranes for optically transparent applications