Low cost, rapid fabrication of durable molds of grating arrays for nanoimprint lithography

This study proposes a new fabrication method for the mold of a sub-micron grating array used in the nanoimprint lithography process. In general, the mold of a sub-micron grating array is fabricated by electron beam lithography (EBL) and reactive ion etching (RIE), and then, nanoimprint lithography (NIL) is used to achieve the required amount of replication. Such a method is expensive and has a low throughput, and the pattern is limited by the original mold. In this paper, we constructed a durable mold of a sub-micron grating array with good adaptability, using a commercial epoxy grating (EG) and a hybrid inorganic/organic sol-gel material combined with nanoimprint lithography and photolithography. Due to its low cost and ease of use, this method is suitable for both laboratory research and mass production without the need for expensive equipment like EBL or RIE.     

应用于MEMS气密性封装测试的微型湿度传感器的设计与制作

MEMS器件的封装一直是MEMS技术的难点之一 ,在封装设计中 ,如何测试封装的有效性就显得尤为重要。本文叙述了一种基于MEMS技术的微型湿度传感器的原理、设计以及工艺流程。在其上进行气密性封装 ,则可通过对封装内的湿度测量来判断该封装的气密性能。在设计中 ,充分考虑了尺寸、工艺以及灵敏度等各方面要求。制作采用的是传统的光刻、刻蚀工艺。该湿度传感器结构简单 ,易于制作 ,其性能能够满足气密性封装测试的要求     

Enhancement of photo- and electro-luminescence of GaN-based LED structure grown on a nanometer-scaled patterned sapphire substrate

In this study, a 2 in. sized a highly periodic nanometer-scaled patterned sapphire substrate (NPSS) was fabricated using nanoimprint lithography (NIL) and inductively coupled plasma etching to improve the light-extraction efficiency of GaN-based light-emitting diodes (LEDs). A blue LED structure was grown on the nanometer-scale patterned sapphire substrates, and the photoluminescence (PL) and electroluminescence (EL) were measured to confirm the effectiveness of the nanometer-scaled patterns on sapphire. An improvement in luminescence efficiency was observed when NPSS was applied; 2 times stronger PL intensity and 2.8 times stronger EL intensity than the LED structure grown on the unpatterned sapphire wafers were measured. These results show highly periodic nanometer-scaled patterns create multi-photon scattering and effectively enhance the light-extraction efficiency of LEDs.     

A novel loading and demoulding process control in UV nanoimprint lithography

In UV nanoimprint lithography (NIL) with elastic mould, a novel multi-step loading and demoulding process, called distortion reduction by pressure releasing (DRPR) and two-step curing method for demoulding, is developed. This novel imprint process is continuous, the pressure releasing method, used to optimize the loading process, can reduce the distortions of imprint mould and wafer stage, while obtain better cavity filling and thin and uniform residual layer; through two-step curing method instead of traditional simple demoulding, the curing degree of resist can be controlled, which is helpful to decrease the demoulding force and avoid residual layer pulled-up while ensure replicated protrusions not collapse. It is a novel and robust process with high fidelity of pattern replication in micro/nano structures fabrication, and the replication error caused by distortions and “blind” demoulding can be reduced effectively.     

Dual step EBL Gate fabrication technology for GaN-HEMT wideband applications

The operation at frequencies above 100 GHz of electronic devices like transistors has been achieved both by using high electron mobility III-V semiconductor materials or heterostructures and by implementing fabrication techniques which strongly reduce parasitic capacitances between the device terminals, without increasing series resistances. The technology has been applied on different GaN high electron mobility transistor epiwafers, and the devices performances analyzed under their DC and RF characteristics, outlining that further semiconductor material optimization is mandatory to fully benefit the sub ¼ micron Gate length for very high frequency operation advantage.     

终端式MEMS微波功率传感器的设计与制作

A terminating type MEMS microwave power sensor based on the Seebeck effect and compatible with the GaAs MMIC process is presented. An electrothermal model is introduced to simulate the heat transfer behavior and temperature distribution. The sensor measured the microwave power from –20 to 20 dBm up to 20 GHz. The sensitivity of the sensor is 0.27 mV/mW at 20 GHz, and the input return loss is less than –26 dB over the entire experiment frequency range. In order to improve the sensitivity, four different types of coplanar waveguide （CPW） were designed and the sensitivity was significantly increased by about a factor of 2.     

MEMS波长可调谐激光器及其进展

论述了MEMS波长可调谐激光器及其进展。介绍了几种不同类型的波长可调谐激光器,如基于表面微机械反射镜的MEMS可调谐激光器、基于深腐蚀圆形反射镜的MEMS可调谐激光器、基于闪耀光栅的MEMS可调谐激光器、基于阵列集成的MEMS可调谐DFB激光器和VCSEL基MEMS可调谐激光器。     

Modeling and characterization of three kinds of MEMS resonators fabricated with a thick polysilicon technology

Three different kinds of two-port flexural resonators, with both clamped and free ends, and with nominal resonance frequencies between 5 MHz and 50 MHz, were designed and fabricated. Among them, a novel free-free third-mode resonator, as well as a tunable free-free resonator, designed to maintain a high quality factor despite its tunability, are presented. Because of reduced energy loss in the clamps, higher quality factors are expected from free-free devices. To estimate the resonators performance, the effect of temperature and axial stresses on the resonators is investigated: for the clamped-clamped resonator, a theoretical model is also presented. FEM simulations are performed for the three geometries and the results are discussed. Dario Paci studied electronic engineering at University of Pisa and at “Scuola Superiore Sant’Anna”. He received his Master Degree in 2003, with a dissertation on MEMS resonators for RF applications. In 2003 he worked at PEL-ETHZ for three months, modelling chemical sensors. In 2005 he was visiting scholar at the Katholieke Universiteit Leuven (Belgium), working at IMEC on MEMS resonators anchor losses modeling. His research interests include MEMS modelling and design and development of circuits for MEMS conditioning. Now he is pursuing the Ph.D. in Information Engineering at University of Pisa, and he is working as a research assistant for the IEIIT of the Italian National Council for the Research (CNR). Massimo Mastrangeli got the MS degree in Electronic Engineering at the University of Pisa (Italy) on July, 2005; his thesis concerned project and measurements of MEMS flexural resonators. During summer 2005 he was visiting scholar at the Katholieke Universiteit Leuven (Belgium), working at IMEC on the mechanical characterization of PolySiGe layers for MEMS applications. He is currently a PhD student at KULeuven, developing a techniques for self-assembly of IC/MEMS for highly integrated microsystems. Andrea Nannini received his laurea degree in Electronic Engineering from the University of Pisa, Italy, in 1982; He received his Ph.D degree in 1987 at the end of the first Italian Ph.D course held by the University of Padova, Italy. From 1988 to 1992 he was a Researcher at the "Scuola Superiore di Studi Universitari e Perfezionamento S. Anna" – Pisa- Italy. Since 1992 he joined the Department of Information Engineering of the University of Pisa as an Associate Professor. Since November 2000 he is a full professor of “Sensor and Microsystem Design”. He is currently chairman of the postgraduate school of Electronic Engineering and vice-chairman of the PhD school of Information Engineering of the University of Pisa. His main research interests concern solid state sensors, microelectronic devices and technologies, MEMS. Francesco Pieri received the laurea and the Ph.D. degree in Electrical Engineering, both from the University of Pisa, Italy, in 1996 and 2000 respectively. He joined the Department of Information Engineering of the same University as an assistant professor in 2001. His current research interests include applications of porous silicon to sensors and microtechnologies, and development of microelectromechanical systems.     

用于MEMS器件的高性能运算放大器的IC设计与测试

根据特定电容式微传感器后续处理电路的高性能要求。设计一个运算放大器芯片，设计中采用了美国MOSIS公司提供的n阱0.35μm cmos工艺的SPICEBSIM3mos管模型。手算估计芯片的参数，然后采用了两种能系统反映芯片特性的测量电路对设计进行了性能测量。并根据测试结果对设计微出相应调整，从最终测试结果来看。设计的运算放大器具有很好的静态和动态性能。     

A solvent-free lift-off method for realizing vertical organic transistors with low leakage current and high ON/OFF ratio

A solvent-free lift-off method has been introduced to fabricate the aluminum nano-hole array with diameter down to 80 nm as the base electrode for a vertical organic transistor. The imprinted vertical organic transistor exhibited base leakage current density as low as 5 × 10⁻⁵ mA/cm² and high ON/OFF current ratio as high as 10⁵.     

翘板式射频MEMS开关的研究

提出了一种新型的翘板式静电射频微系统开关,给出了理论模拟,结构分析结果和工艺制作方法。该结构采用了5μm厚的无应力单晶硅作为开关的可动部分,可以缓解薄膜应力变形。翘板式结构解决了传统静电设计中动作力弱的问题,并且通过调整支点解决了开关回复力不可调的难题。利用该结构可以在保持高隔离度的同时使驱动电压降低,有限元理论模拟驱动电压为5~10V;采用翘板式结构增加了开关的使用周期,而且结构自身具有单刀双掷特点,可以直接应用于高频通信的频道选择。给出了开关共面波导传输线的测试结果和设计讨论。     

基于MEMS工艺的硅基红外辐射源研制

利用微机电系统( MEMS)制造工艺制备出了一种硅基红外辐射源.该辐射源采用单晶硅为衬底,通过直流溅射沉积Pt/Ti薄膜,并利用深反应离子刻蚀与湿法腐蚀工艺制备隔离槽和释放支撑层.研究了支撑层厚度对红外辐射源辐射特性的影响.结果表明,随着支撑层厚度的减小,红外辐射源的调制驱动电压会降低.当支撑层厚度为1μm时,辐射源调...     

一种双稳态电磁型射频MEMS开关的设计与测试

设计了一种低电压驱动的双稳态电磁型射频MEMS开关.与驱动电压高这几十伏的静电型射频MEMS开关相比,其驱动电压可低至几伏,因此应用时无需增加电荷泵等升压电路.开关可在磁场驱动下实现双稳态切换,稳态时无直流功率消耗.分析了工作磁场的分布特点,进行了结构设计仿真;并使用HFSS软件和粒子群算法进行了射频参数仿真、结构参数优化及主要结构参数显著性研究,得出了影响开关射频传输性能的主要结构参数;采用表面牺牲层工艺制作了原理样机并进行了射频性能参数的测试.结果表明,开关样机在DC～3 GHz工作频率区间内,插入损耗小于0.25 dB,隔离度大于40 dB.     

A fast-developing and low-cost characterization and test environment for a double axis resonating micromirror

Testing and characterization of micro-electro-mechanical systems (MEMS) and micro-opto-electro-mechanical systems (MOEMS) can be very challenging due to the multi-domain nature of these devices. Nowadays high volume, high-cost, and accurate measuring systems are necessary to characterize and test MEMS and MOEMS especially to examine their motions, deflections, and resonance frequencies. This paper presents a fast-developing and low-cost environment for MEMS and MOEMS testing and characterization. The environment is based on a flexible mixed-signal platform named Intelligent Sensor InterFace (ISIF). As a case study we consider the characterization of a double axis scanning micromirror. The testing environment has been validated by comparing measurement results with results obtained by the finite element method simulations performed with Comsol Multiphysics. Finally, these results have been exploited to create an electrical equivalent model of the micromirror.     

MEMS微加速度与微角速率集成传感器的研制

介绍了一种全新的MEMS微型惯性器件,该器件是一种基于热对流原理的热膜式传感器,它利用一个单敏感元件同时测量加速度和角速率。该器件由一个加热器和两组微型温度传感器组成,加热器加热气体形成的热对流气体作为敏感元件,该器件通过微型温度传感器测得的热对流气体的温度差实现加速度和角速率的测量。分析了器件的工作原理,根据仿真结果设计了双层的器件结构,进行了工艺开发,加工出了原理样机。测试表明:该器件同时具备了加速度传感器和角速率传感器的检测功能,很好地验证了设计的可行性。     

射频MEMS技术在雷达中的应用现状与优势

射频MEMS技术为实现微型化、集成化及智能化,以及探索具有新原理和新功能的器件与系统提供了重要途径。概述了射频MEMS的主要优势和在雷达领域的主要应用方向,在此基础上重点介绍了国外基于射频MEMS技术的T/R组件设计、X波段相控阵天线演示验证系统及针对Ka波段低成本无源相控阵的探索情况,并给出了新一代MEMS高集成度电子扫描阵列研究项目的最新进展。     

微机械圆盘谐振器的仿真分析及等效电路

通过对径向振动圆盘的机械振动方程进行分析,将机械振动的分散参数集总化,提取出机械集总参量并通过机电类比的方法将集总化的机械参量类比成电参量,建立起径向振动微机械谐振器的电参数模型。利用ANSYS软件对径向振动盘式微机械谐振器进行模拟,提取出谐振频率和振动位移,并以此为基础计算出等效质量及阻尼和刚度的数值,进而通过机电耦合系数求出电参数值。以所提取的电参数为依据,分析了谐振器的结构对谐振器的等效阻抗的影响。谐振器的等效电路及分析结果将成为后续结构和驱动电路设计的出发点。     

MEMS毫米波滤波器的设计与制作

开展了一种基于MEMS工艺的毫米波带通滤波器结构设计和工艺实现,该滤波器结构采用高阻硅作为衬底材料的薄膜支撑结构,选用平行耦合滤波器形式,使用HFSS分析软件对该结构进行了模拟仿真。设计了中心频率为35.0GHz、带内损耗为2.2dB、30dB抑制带宽为2.2GHz的MEMS毫米波滤波器。给出了一套能降低毫米波损耗的MEMS毫米波带通滤波器工艺流程方案,并针对该工艺流程方案进行了关键参数的工艺误差仿真,实现了MEMS毫米波滤波器的工艺制作和测试。测试结果表明,获得的毫米波滤波器的测试结果与仿真结果比较接近。     

一种新型微机械硅弹簧的设计与制作

介绍了一种新型的微机械硅弹簧的设计和制作,运用能量方法推导出了弹性常数的计算公式,并用有限元模拟分析方法求出了其固有频率。有限元模拟工具ANSYS模拟的结果验证了弹性常数的计算公式,理论分析和实际加工表明设计方案是可行的。     

Compact meta-material transmission line balun based on meander lines structure and MEMS technology

This paper presents a novel compact meta-structure microstrip balun, which is characterized by left-handed properties. In the novel structure, two coupled meander lines are used to generate series capacitor and series inductor. Compared with conventional composite right/left-handed transmission-line structures, the new structure has smaller size and is easily fabricated by MEMS (Micro Electromechanical Systems) technology. Using such a meta-structure, a wide band microstrip balun is designed and fabricated. Good performance in phase error in wide pass band has been achieved.