High aspect-ratio combined poly and single-crystal silicon (HARPSS)MEMS technology

This paper presents a single-wafer high aspect-ratio micromachining technology capable of simultaneously producing tens to hundreds of micrometers thick electrically isolated poly and single-crystal silicon microstructures. High aspect-ratio polysilicon structures are created by refilling hundreds of micrometers deep trenches with polysilicon deposited over a sacrificial oxide layer. Thick single-crystal silicon structures are released from the substrate through the front side of the wafer by means of a combined directional and isotropic silicon dry etch and are protected on the sides by refilled trenches. This process is capable of producing electrically isolated polysilicon and silicon electrodes as tall as the main body structure with various size capacitive air gaps ranging from submicrometer to tens of micrometers. Using bent-beam strain sensors, residual stress in 80-μm-thick 4-μm-wide trench-refilled vertical polysilicon beams fabricated in this technology has been measured to be virtually zero. 300-μm-long 80-μm-thick polysilicon clamped-clamped beam micromechanical resonators have shown quality factors as high as 85 000 in vacuum. The all-silicon feature of this technology improves long-term stability and temperature sensitivity, while fabrication of large-area vertical pickoff electrodes with submicrometer gap spacing will increase the sensitivity of micro-electromechanical devices by orders of magnitude     

微纳机电开关研究现状

微纳机电开关是指特征尺寸在微米或纳米量级内的机械开关,是一个新兴的技术领域,具有体积小、速度快、零泄漏等优势,成为近年来的研究热点。首先介绍了微纳机电开关在射频器件和逻辑电路中的应用,并概述了其分类方式及各自特点。同时系统综述了微纳机电开关的研究现状,包括在尺寸、阈值电压、稳定性、材料等方面取得的突破。最后,论述了微纳机电开关的发展趋势,阐述了其面临的问题和发展障碍,如微纳尺寸下的表面粘附效应、现有工艺技术的实现等。     

A design methodology for fully integrated MEMS and NEMS Pierce oscillators

This work proposes a generic methodology to evaluate the feasibility of designing a Pierce oscillator based on a micro or nanoresonator fabricated with any given CMOS technology and with the constraint of using only one single active transistor. Both the design and the transimpedance gain of the electronics are analytically determined for resonators with capacitive or resistive detection. This approach is applied and validated in the case of (a) an electrostatically actuated clamped-clamped beam resonator using a capacitive transduction, and (b) a piezoresistive crossbeam, both based on a standard 0.13 μm CMOS technology.     

交流电沉积实现微纳器件定向连接研究

使用交流电化学方法定向制备了预制微电极之间的电连接。通过调节交流电压与偏置直流电压幅值可以控制电连接的生长方向。如果施加的交流电压幅值高于生成电连接的电压阈值,并且该值恒定时,频率越小,浓度越大,电连接晶体越粗壮;而当电解液浓度与频率恒定时,电压幅值变化对形貌影响较小。有限元仿真模拟进一步说明：当施加的交流电压高于阈值时,电极处于交流电渗流上游。电极扩散层厚度增加将诱导电极之间电连接晶体的生长。在交流电压上叠加直流偏置电压时,电连接晶体从偏置电压相对较负的一端向另一端生长。伏安特性测试结果表明：该连接具有优异的接触特性。     

Pull-in behavior of functionally graded micro/nano-beams for MEMS and NEMS switches

Microsystem Technologies - In this paper, pull-in behavior of cantilever micro/nano-beams made of functionally graded materials (FGM) with small-scale effects under electrostatic force is...     

De-tethering of high aspect ratio metallic and polymeric MEMS/NEMS parts for the direct pick-and-place assembly of 3D microsystem

We report our study on several de-tethering methods for various high aspect ratio metallic and polymeric MEMS and NEMS parts including 5:1 aspect ratio 50 μm thick metallic (nickel) MEMS parts, 3:1 aspect ratio 1 μm thick sub-micron (350 nm) feature size metallic NEMS actuators, and 10:1 aspect ratio 100 μm thick polymer/metal bi-layer MEMS actuators. Resistive heating was found to be effective for the de-tethering of high aspect ratio metallic MEMS parts. In order to de-tether metallic NEMS parts and polymer/metal bi-layer devices, we performed the milling of tethers using a focused ion beam. Very low current (20 pA) ion beam was found to be effective means of de-tethering the metallic NEMS parts. Relatively larger current (0.3–20 nA) ion beam was found to be good for the polymer/metal bi-layer parts. We demonstrated 3D assembly and complete packaging of the de-tethered high aspect ratio metallic and metal/polymer bilayer MEMS parts.     

采用RIE沉积法研制微纳工艺中的防粘连层

摩擦和粘附问题已经成为影响微机电系统(MEMS)工艺性能和可靠性的主要因素.针对MEMS/NEMS中微构件表面改性问题,采用反应离子刻蚀(RIE)在硅片表面沉积氟化物薄膜,以达到降低硅片的表面能,减少其摩擦和粘附的目的.实验还将RIE沉积法制得的薄膜与自组装(SAMs)薄膜在浸润角、表面能、表面粗糙度等方面进行了对比.     

Advancements in technology and design of NEMS vector hydrophone

This paper reports on recent developments to improve the performance of hair vector hydrophone by means of several technological advancements in the fabrication procedures and corresponding sensor design. With fish’s lateral line organs as prototypes, NEMS (Nano-Electromechanical System) vector hydrophone with directivity has been designed. This paper describes the meso-piezoresistance effect of resonant tunneling thin-film, and the NEMS hydrophone based on this effect is highly sensitive and small size. The application of bionics structure may improve the low-frequency sensitivity of hydrophone. The calibration test shows that NEMS vector hydrophone’s receiving sensitivity is up to −170 dB (0dB = 1 V/μPa), has a good directional pattern in the form of “8” shape. The sea test shows that the direction of target can be detected by single NEMS vector hydrophone. In the anechoic tank, it has been verified that NEMS vector hydrophone can track the trajectory of the moving target.     

Pulsed electrodeposition of high aspect-ratio NiFe assemblies and its influence on spatial alloy composition

Direct- and pulse-reverse current electrodeposition processes and their influence on the spatial nickel-iron alloy composition are described. High-aspect ratio gear wheel structures are electroplated from a nickel sulphate/iron sulphate bath. Subsequent determination of the iron content at the gear-wheels cross section using scanning electron microscopy demonstrates that pulse reverse plating results in an uniform alloy composition across different structure dimensions. By contrast, local variations in iron content were observed in case of direct current plating.     

基于MEMS的生物微传感技术

微电子机械系统(MEMS)技术为生物微传感器和生物芯片的研制以及实现小型化、便携式、低成本,高灵敏度的生化片上系统提供了有力的技术支持。综述了基于MEMS的生物微传感技术,介绍了生物微传感器和生物芯片的原理、结构、分类及应用,并探讨了其发展和应用前景。     

The lifetime comparison of Ni and Ni-PTFE moulding inserts with high aspect-ratio structure

Micro molding is the key process of LIGA (UV-LIGA) technique for low-cost mass production. It is difficult to demold for high aspect ratio of the structure fabricated by LIGA technique due to adhesion and friction force between the side-walls of the molding inserts and the thermoplastic material (PMMA). In this paper, the life times of the molding inserts made of Nickel (the material usually used for LIGA) and Ni-Teflon (PTFE) compound material are studied. The experiment shows the lifetime of Ni-PTFE molding insert is longer than the one of Ni for across pattern.This work was supported by the national High technology Research and Development Program of China (863 Program, No. 2002 AA404130), and National Natural Science Fundation of China (No. 10375058)     

MEMS/NEMS表面3-D轮廓测量中基于模板的相位解包裹方法

相位解包裹是使用相移显微干涉法测量MEMS/NEMS表面3-D轮廓时的重要步骤.本文针对普通的相位解包裹方法在复杂轮廓或包含非理想数据区的表面轮廓测量中的局限性,提出一种基于模板的广度优先搜索相位展开方法.通过模板的使用,先将非相容区域标记出来,在相位解包裹的过程中绕过这些区域,即可得到准确可靠的相位展开结果.通过具体的应用实例可以证明,使用不同模板可以根据不同应用的需要灵活而准确地实现微纳结构表面3-D轮廓测量中的相位展开.     

一种超宽带MEMS开关的研制

MEMS射频器件,特别是超宽带器件,对其中的射频器件提出了宽带指标的要求。以此为背景,在理论分析的基础上设计了一种应用于12.5 GHz~50 GHz频带的超宽带双膜桥式MEMS开关,该开关具备低损耗、高隔离度等特点,文中给出了开关的制备工艺,并进行流水完成了芯片制备。经测试,该开关在设计频段内,回波损耗优于20 dB,插入损耗典型值0.3 dB@12.5~35 GHz,优于0.5 dB@45 GHz,隔离度全频段优于20 dB,驱动电压在45 V~55 V之间。     

Nonlinear dynamics of MEMS/NEMS resonators: analytical solution by the homotopy analysis method

Microsystem Technologies - Due to various sources of nonlinearities, micro/nano-electro-mechanical-system (MEMS/NEMS) resonators present highly nonlinear behaviors including softening- or...     

基于MEMS技术的气体传感器

综述了目前国内外主要MEMS气体传感器的原理,包括谐振式微悬臂梁型、声表面波型、阻抗变化型、声光法、气体光谱、催化燃烧式和高场非对称波形离子迁移谱(FAIMS)检测法。对各种传感器的特点进行了比较。     

Fabrication of high aspect-ratio polymer microstructures for large-area electronic portal x-ray imagers

Megavoltage X-ray imaging performed during radiotherapy is the method of choice for geometric verification of patient localization and dose delivery. Presently, such imaging is increasingly performed using electronic portal imaging devices (EPIDs) based on indirect detection active matrix flat panel imagers (AMFPIs). These devices use a scintillating phosphor screen in order to convert incident X-rays into optical photons, which are then detected by the underlying active matrix photodiode array. The use of a continuous phosphor introduces a trade-off between X-ray quantum efficiency and spatial resolution, which limits current devices to use only 2% of the incident X-rays. This trade-off can be circumvented by “segmented phosphor screens”, comprising a two-dimensional matrix of optically isolated cell structures filled with scintillating phosphor. In this work we describe the fabrication of mm-thick segmented phosphor screens using the MEMS (micro-electro-mechanical-system) polymer SU-8. This method is capable of being extended to large-area substrates.     

Application of inclined-exposure and thick film process for high aspect-ratio micro-structures on polymer optic devices

In this paper we apply an inclined-exposure technology, while also using a polymeric material to make 3D optical micro-structure like dove prism and hardened reflecting mirrors in blue-DVD pickup head module. In contrast to the more common type of inclined mirrors, single-lensed reflecting mirrors, the micro-reflecting mirror being developed within the scope of this paper possesses the qualities that it requires no metal for its reflecting surface, and it is structurally stable. When used in micro-optical systems, it is less prone to experiencing structural changes and impact to the system’s optical paths as a result of heat generated from the light source. The fabrication technology for dove prism being developed can be used to easily fabricate highly integrated micro-optical systems. The structure being fabricated can reach a height of 1.8 mm, while the degree of surface roughness meets the necessary Marechal optic quality criterion. In this paper we will also issue of the structure of the SU-8 material being wider at the top and narrower at the bottom due to short-wavelength light source having shallower penetration. The polymeric material used has a high penetration rate of 95% (red light), and is low in cost. As such, we may apply and consolidate micro-structures in TIR, CD/DVD, SPR, and micro-PIV systems, or optical systems in general. These novel methods can be employed for the fabrication of nontraditional 3D structures on photo polymer for Optical MEMES applications.     

基于MEMS技术的胎压监测系统的实现

1IntroductionThe micro-electronics machine system(MEMS)ap-pears in the beginning of80's.It is a integral settingwhich integrate the miniature machine,miniature sensor,tiny energy,microcontroller,signal processing and intel-ligent controller.It characterized by small or operationsizes,high integration,intelligentization and low price[1].With the emergence of MEMS technology,It can moni-tor tyre pressure and temperature by means of embody-ing the MEMS pressure sensors into tyre.At present,…