硅微机械谐振压力传感器技术发展

硅微机械谐振压力传感器是目前精度最高、长期稳定性最好的压力传感器之一,是航空航天、工业过程控制和其他精密测量领域压力测试的最佳选择。系统阐述30年来国内外硅微机械谐振压力传感器技术的研究成果,简单介绍硅微机械谐振压力传感器的分类及工作原理,针对压力敏感膜片与谐振器复合结构和振动膜结构两种主要的芯体结构形式,详细论述硅微机械谐振压力传感器的研究历史、主要研究机构、国内外发展现状以及最新的研究成果,重点根据不同激励与检测方式对各种硅微机械谐振压力传感器的芯体结构进行深入分析比较。在此基础上,总结归纳不同芯体结构及其激励与检测方式的特点,并对硅微机械谐振压力传感器的未来发展趋势进行展望。     

基于MEMS技术的硅微机械流体传感器的原理及应用

传统的流体传感器由于存在着灵敏度低、体积大、成本高等缺点,而且微流体与宏观流体流动特性不同,所以其在微流体的流体特性测量中存在很大的局限性。随着MEMS技术的发展,硅微机械流体传感器的出现克服了传统流体传感器的缺点。硅微机械流体传感器已成为MEMS的研究热点之一。按其用途进行了分类,着重介绍了流体压力传感器、流量传感器和表层摩擦力传感器。分别从各种传感器的基本原理、性能、应用范围、优缺点及其所能达到的技术指标方面进行了描述。基于MEMS的硅微机械流体传感器具有广阔的前景。     

高g值微机械加速度传感器的现状与发展

本文对用于侵彻武器和爆炸现场测量的高g值加速度传感器进行了四顾与展望.重点介绍了采用微机械工艺的高g值微加速度传感器.首先分析了目前几种新型压阻式和电容式高g值硅微机械加速度传感器的基本工作原理,主要技术指标和敏感元件的结构特点,讨论了几种用于制作高g值微加速度传感器的新型材料和工艺.最后总结了高g值微机械加速度传感器未来的发展趋势.     

1kPa微机结构微压传感器的研究

本文报道一种量程为１ｋＰａ的扩散硅微机械结构微压传感器。     

谐振式硅微结构传感器综合测试分析仪

提出了一种谐振式硅微结构传感器综合测试分析仪器,用于微机械谐振式传感器各关键环节的测试、分析与评估.主要解决测试对象特性模型、微弱信号处理、测试数据分析评估等问题,并将有关理论和技术集成为一台模块化的、具一定开放性的测试仪器.该测试仪器对于深入掌握谐振式硅微结构传感器谐振子和闭环系统的特性和优化方法,实现高性能微传感器具有重要意义.     

微摩擦测试技术研究进展

随着微型机械的发展,尤其是微摩擦学研究的进展,微摩擦测试技术显得极为重要。综述了国内外微摩擦测试技术的研究进展和现状,介绍了基于应变仪、压力传感器、电磁微型马达、硅微机械结构、浮力、光学检测等原理的微摩擦测试仪,分析了它们的工作原理和特点。     

硅微机械传感器的技术特点及发展趋势

基于硅微机械传感器的技术特点,分析了这类传感器的发展趋势,同时指出了它进一步发展中急需解决的几个问题。     

降低硅微机械加速度传感器横向灵敏度的方法

本文分析了硅微机械加速度传感器横向灵敏度产生的原因,并介绍了降低它的方法。     

一种新型的硅谐振式微传感器频率特性测试系统

针对硅微机械谐振式压力传感器,设计了一种新型的专用频率特性测试系统,采用直接相关原理进行微弱信号检测,简化了模拟电路设计;提出了分时正交的检测方法解算被测样件的幅频、相频特性.实验结果表明:系统实现了对硅微机械谐振式压力传感器的幅频和相频特性的同时测量,实测结果与理论值符合,不仅给出了闭环设计的必要参数,同时为加工工艺的改进提供了重要信息.     

1kPa 微机械结构微压传感器的研究

本文报道一种量程为１ｋＰａ的扩散硅微机械结构微压传感器。实现了高灵敏度微压传感器的非线性内补偿和强过载保护以及高共振频率,分析研究了最佳条件。微压传感器的非线性为０．１％ＦＳ,其过载保护能力已超过５００倍满程压力,共振频率为９ｋＨｚ。     

Coaxial probes for scanning near-field microscopy

This paper deals with the development of coaxial aperture tips integrated in a cantilever probe for combined scanning near-field infrared microscopy and scanning force microscopy. A fabrication process is introduced that allows the batch fabrication of hollow metal aperture tips integrated on a silicon cantilever. To achieve the coaxial tip arrangement a metal rod is deposited inside the hollow tip using the focused ion beam technique. Theoretical calculations with a finite integration code were performed to study the transmission characteristics of coaxial tips in comparison with conventional aperture probes. In addition, the influence of the geometrical design parameters of the coaxial probe on its optical behaviour is investigated.     

Coaxial probes for scanning near-field microscopy

This paper deals with the development of coaxial aperture tips integrated in a cantilever probe for combined scanning near-field infrared microscopy and scanning force microscopy. A fabrication process is introduced that allows the batch fabrication of hollow metal aperture tips integrated on a silicon cantilever. To achieve the coaxial tip arrangement a metal rod is deposited inside the hollow tip using the focused ion beam technique. Theoretical calculations with a finite integration code were performed to study the transmission characteristics of coaxial tips in comparison with conventional aperture probes. In addition, the influence of the geometrical design parameters of the coaxial probe on its optical behaviour is investigated.     

Editorial

Near-field optical microscopy is the optical alternative of the various types of scanning probe microscopes. The technique overcomes the classical diffraction limit in conventional optical microscopy. In this paper the concepts of near-field optics (NFO) are introduced, followed by a short review of current trends in NFO microscopy. Specifically, developments concerning the efficiency and versatility of both aperture and dielectric probe types are discussed. We present our advances in NFO microscopy, using both fibres and integrated silicon nitride (SiN) structures as dielectric probes. The use of an SiN probe as a combined optical and force sensor is shown to be advantageous, as it provides a feedback mechanism and allows direct comparison between topography and dielectric effects. Images of technical and biological samples are presented with a lateral resolution down to 20 nm, depending on the microscopical arrangement used.     

新型真空微电子氢气传感器

研究了一种新型真空微电子氢气传感器,其原理为气体在高电压激发下发射出与其吸收光谱相同的特征光普。用微机械加工方法在硅片加工出密封的充满H2的微气室,在一定电压下阴极发射电子,气体分子被电离,发射特征光谱。当外界H2存在时,会吸收特征光谱,这一吸收具有高选择性。微气室中微机械加工出纳米尺寸冷阴极硅尖端,在低电压下就可以产生场发射。检测器可以使用普通的光电二极管。     

微装配正交精确对准系统的设计

针对平板类零件微装配系统设计过程中面临的问题,提出采用正交光学对准机构来实现用人机协同的微装配系统对微小型平板类结构件的高精度装配,并分析计算高精度对准机构模块产生的误差.建立了基于显微机器视觉及正交光学对准的微装配系统平台,用本文提出的方法进行了微装配实验,结果显示本装配系统在装配的一致性与装配效率方面有较大的改善与提高.提出的光学对准方法可有效地用于平板结构的硅微MEMS器件和非硅MEMS器件等集成的复杂微小型异构机电系统的装配,设计的平台具有很好的开放性和可移植性.棱镜正交对准机构产生0.001°的角度误差时,对准理论偏差小于0.98 μm,实际实验中微装配平台系统装配精度小于5μm,满足平板类微小型结构件装配一般精度需求.     

Numerical analysis of crater formation and ablation depth in thin silicon films heated by ultrashort pulse train lasers

This study numerically investigates the optical and heat transfer characteristics of thin silicon films irradiated by ultrashort (shorter than 10 ps) pulse train lasers. The one-dimensional two-temperature model (1DTTM) is extended to the two-dimensional (2DTTM) model for estimation of crater formation. In addition, the wave interference effects on the optical and energy transfer characteristics are considered to predict accurately the energy absorption rates in thin silicon films irradiated by picosecond-to-femtosecond pulse train lasers. Unlike bulk silicon, a significant change in energy absorption is found to occur in thin silicon films with the variation of film thickness due to the wave interference. The spatial distributions of energy carrier and lattice temperature show quite a different tendency at different pulse durations as well as the number of pulses because of significant changes in the optical and thermal properties. The predicted crater shapes and the ablation depths by 2DTTM are also presented.     

Continuous planar phospholipid bilayer supported on porous silicon thin film reflector

Reconstituting artificial membranes for in vitro studies of cell barrier mechanisms and properties is of major interest in biology. Here, artificial membranes supported on porous silicon photonic crystal reflectors are prepared and investigated. The materials are of interest for label-free probing of supported membrane events such as protein binding, molecular recognition, and transport. The porous silicon substrates are prepared as multilayered films consisting of a periodically varying porosity, with pore dimensions of a few nanometers in size. Planar phospholipid bilayers are deposited on the topmost surface of the oxidized hydrophilic mesoporous silicon films. Atomic force microscopy provides evidence of continuous bilayer deposition at the surface, and optical measurements indicate that the lipids do not significantly infiltrate the porous region. The presence of the supported bilayer does not obstruct the optical spectrum from the porous silicon layer, suggesting that the composite structures can act as effective optical biosensors.     

Real-time displacement measurements with a Fabry-Perot cavity and a diode laser

We present the basic operating principles of a traceable measurement system suitable for use with atomic force microscopes (AFMs) and nanometer-resolution displacement sensors. Our method is based upon a tunable external-cavity diode laser system which is servo-locked via a phase-modulated heterodyne locking technique to a Fabry-Perot interferometer cavity. We discuss mechanical considerations for the use of this cavity as a displacement metrology system and we describe methods for making real-time (sub 10 ms sampling period) measurements of the optical heterodyne signals. Our interferometer system produces a root-mean-squared (RMS) displacement measurement resolution of 20 pm. Two applications of the system are described. First, the system was used to examine known optical mixing errors in a heterodyne Michelson interferometer. Second, the Fabry-Perot interferometer was integrated into the Z axis of a commercial AFM scanning stage and used to produce interferometer-based images of a 17 nm step height specimen. We also demonstrate atomic resolution interferometer-based images of a 0.3 nm silicon single atomic step-terrace specimen.     

Moulded photoplastic probes for near-field optical applications

The inexpensive fabrication of high-quality probes for near-field optical applications is still unsolved although several methods for integrated fabrication have been proposed in the past. A further drawback is the intensity loss of the transmitted light in the 'cut-off' region near the aperture in tapered optical fibres typically used as near-field probes. As a remedy for these limitations we suggest here a new wafer-scale semibatch microfabrication process for transparent photoplastic probes. The process starts with the fabrication of a pyramidal mould in silicon by using the anisotropic etchant potassium hydroxide. This results in an inverted pyramid limited by < 111 > silicon crystal planes having an angle of ∼ 54°. The surface including the mould is covered by a ∼ 1.5 nm thick organic monolayer of dodecyltrichlorosilane (DTS) and a 100-nm thick evaporated aluminium film. Two layers of photoplastic material are then spin-coated (thereby conformal filling the mould) and structured by lithography to form a cup for the optical fibre microassembly. The photoplastic probes are finally lifted off mechanically from the mould with the aluminium coating. Focused ion beam milling has been used to subsequently form apertures with diameters in the order of 80 nm. The advantage of our method is that the light to the aperture area can be directly coupled into the probe by using existing fibre-based NSOM set-ups, without the need for far-field alignment, which is typically necessary for cantilevered probes. We have evidence that the aluminium layer is considerably smoother compared to the 'grainy' layers typically evaporated on free-standing probes. The optical throughput efficiency was measured to be about 10⁻⁴. This new NSOM probe was directly bonded to a tuning fork sensor for the shear force control and the topography of a polymer sample was successfully obtained.     

Silicon technology-based micro-systems for atomic force microscopy/photon scanning tunnelling microscopy

We developed silicon nitride cantilevers integrating a probe tip and a wave guide that is prolonged on the silicon holder with one or two guides. A micro-system is bonded to a photodetector. The resulting hybrid system enables us to obtain simultaneously topographic and optical near-field images. Examples of images obtained on a longitudinal cross-section of an optical fibre are shown.