RFMEMS电容式并联开关的研制

通过分析MEMS电容式并联开关的工作原理,设计并制作出一款适合Ka波段分布式MEMS移相器的电容式开关。通过理论计算和经验选取,初步得到了MEMS电容式并联开关的结构尺寸。采用HFSS软件建立了开关的三维电磁场模型并优化了关键结构参数。仿真表明开关在Ka波段插入损耗小于0．15dB,回波损耗大于15dB。采用CoventorWare软件进行了开关的机电耦合仿真,得出其驱动电压为2．1V。为了满足流片单位的实际工艺约束条件,对开关的设计版图和微加工工艺进行了多轮改进,研制成功MEMS电容式并联开关工艺样品。开关动态特性测试表明,在驱动电压36V时,桥下拉的高度约为2μm。     

低电压电容式RF MEMS开关设计研究

本文设计了一种低电压电容式RFMEMS开关,开关采用了两端固支梁结构,在梁与CPW共面波导地线的四个固定支撑位置使用了折叠结构,该结构可以减低下拉电压;通过在MEMS开关梁上开孔（直径9μm圆孔）来减小残余应力和杨氏模量和选择合适的开关梁厚度,显著降低了MEMS开关梁的弹性系数和下拉电压。以上措施显著降低了电容式RFMEMS开关的下拉电压,在ANSYS仿真下拉电压约为6V,驱动电压约为8.4V,该MEMS开关依旧保持了较好的S参数,开关插入损耗大于-0.35dB(8-40GHz),回波损耗小于-22dB(8-40GHz),隔离度（down态S21）大于25dB(8-40GHz)。     

电气和电子工程用材料科学

TB43 02040018铝硅合金膜在MEMS电容式开关中的应用/忻佩胜,丁玲,石艳玲,朱自强,赖宗声(华东师范大学) 半导体技术。-2001,26(12)。-75-77对几种可用于MEMS电容式开关中的弹性薄膜材料进行了分析,含硅4％轻质量铝合金具有较佳的性能。应用该弹性膜制备了微波MEMS电容式开关,实验结果表明,开关具有较低的激励电压,约为28V,在10GHz处的隔离度大于15dB。图4参5(午)     

多晶硅微机械开关

利用LPCVD SiO2和多晶硅作牺牲层和悬臂梁技术,解决了多晶硅应力释放问题以及微机械开关工艺与IC工艺兼容技术问题,获得了淀积弱张应力的多晶硅膜的最佳工艺条件,研制出多晶硅微机械开关.初步测试出其开关的开启电压为89V,开关速度为5μs,这为研制用于雷达和通讯的全单片集成的RF MEMS开关系统打下了基础.     

多晶硅微机械开关

利用LPCVD SiO2和多晶硅作牺牲层和悬臂梁技术,解决了多晶硅应力释放问题以及微机械开关工艺与IC工艺兼容技术问题,获得了淀积弱张应力的多晶硅膜的最佳工艺条件,研制出多晶硅微机械开关.初步测试出其开关的开启电压为89V,开关速度为5μs,这为研制用于雷达和通讯的全单片集成的RF MEMS开关系统打下了基础.     

铝硅合金膜在MEMS电容式开关中的应用

对几种可用于MEMS电容式开关中的弹性薄膜材料进行了分析,含硅4%的轻质量铝合金具有较佳的性能。应用该弹性膜制备了微波MEMS电容式开关,实验结果表明,开关具有较低的激励电压,约为28V,在10GHz处的隔离度大于15dB。     

低压驱动RF MEMS开关设计与模拟

RF MEMS开关存在驱动电压高、开关时间长等问题,利用ANSYS对电容式开关加以改进,设计扭转臂杠杆与打孔电容膜相结合的新型开关。通过静电耦合与模态分析的仿真,可以在理论上改善RF MEMS开关的射频性能,并有工艺的可行性。     

电磁驱动推拉式射频MEMS开关的设计与制作

提出了一种新型电磁驱动推拉式射频MEMS开关。针对传统静电驱动单臂梁开关所需驱动电压大、恢复力不足等问题,设计了一种推拉式开关结构,降低了驱动电压(电流),提高了开关的隔离度,同时实现了单刀双掷的功能。单晶Si梁由于自身无应力,解决了悬臂梁残余应力引起的梁变形问题。通过理论计算和有限元分析,优化了开关设计尺寸,在外围永磁铁磁感应梯度dB/dz=100T/m,在线圈通入100mA电流的驱动下,单晶Si扭转梁末端可以获得约10μm的弯曲量,满足开关驱动要求。给出了开关的详细微细加工流程,对开关的传输参数进行了测试,在10GHz时隔离度为-40dB.     

RF MEMS开关工艺技术研究

RFMEMS开关是用MEMS技术形成的新型电路元件,与传统的半导体开关器件相比具有插入损耗低、隔离度大等优点,将对现有雷达和通信中RF结构产生重大影响。文章介绍了RFMEMS开关的基本工艺流程设计,工艺制作技术的研究。实验解决了种子层技术、聚酰亚胺牺牲层技术、微电镀技术的工艺难题,制作出了RFMEMS开关样品,基本掌握了RFMEMS器件的制作工艺技术。RFMEMS开关样品测试的技术指标为:膜桥高度2μm～3μm、驱动电压<30V、频率范围0～40GHz、插入损耗≤1dB、隔离度≥20dB,样品参数性能达到了设计要求。     

分布式MEMS移相器电容开关时间响应特性研究

提出一种适合于分析微波分布式MEMS移相器静电驱动电容开关的开启时间和动态特性的新方法。采用IntelliSuite~(TM)模拟工具的SYNPLE模块研究材料、驱动电压、MEMS桥高度和共面波导信号线宽度对电容开启时间的影响。通过优化参数,分析结果表明:对于金电容开关,V=40 V、g_0=2.5μm和W=100μm,开关的开启时间为～7μs。     

一种新型低压电容式RF MEMS开关的设计与分析

介绍了一种基于扭转的新型低压电容式RFMEMS开关的设计.此开关在保留传统挠曲变形的基础上,引入了扭转变形,并利用Intelli Suite等软件进行仿真分析.理论分析和仿真结果表明:与传统弯曲变形不同,在扭转变形中,变形对臂的厚度远比宽度敏感;在保留传统挠曲变形的基础上,增加了扭转变形,将有效降低驱动电压.理论分析还表明增长扭转臂、从动臂可使驱动电压明显下降.通过优化结构设计,在扭转臂、从动臂长为180μm、120μm,臂宽为5μm,厚为1μm,驱动电极面积为120μm×120μm时,仿真得到驱动电压为1.5V.     

Self‐Repairable,High Permittivity Dielectric Elastomers with Large Actuation Strains at Low Electric Fields

A one‐step process for the synthesis of elastomers with high permittivity, excellent mechanical properties and increased electromechanical sensitivity is presented. It starts from a high molecular weight polymethylvinylsiloxane, P1 , whose vinyl groups serve two functions: the introduction of polar nitrile moieties by reacting P1 with 3‐mercaptopropionitrile ( 1 ) and the introduction of cross‐links to fine tune mechanical properties by reacting P1 with 2,2′‐(ethylenedioxy)diethanethiol ( 2 ). This twofold chemical modification furnished a material, C2 , with a powerful combination of properties: permittivity of up to 10.1 at 10⁴ Hz, elastic modulus Y_10% = 154 kPa, and strain at break of 260%. Actuators made of C2 show lateral actuation strains of 20.5% at an electric field as low as 10.8 V μm^–1. Additionally, such actuators can self‐repair after a breakdown, which is essential for an improved device lifetime and an attractive reliability. The actuators can be operated repeatedly and reversibly at voltages below the first breakdown. Due to the low actuation voltage and the large actuation strain applications of this material in commercial products might become reality.     

New Silicone Composites for Dielectric Elastomer Actuator Applications In Competition with Acrylic Foil

Several polydimethylsiloxane elastomers were developed and investigated regarding their potential use as materials in dielectric elastomer actuators (DEA). A hydroxyl end‐functionalized polydimethylsiloxane was reacted with different crosslinkers and the electromechanical properties of the resulting elastomers were investigated. The silicone showing the best actuation at the lowest electric field was further used as matrix and compounded with encapsulated conductive polyaniline particles. These composites have enhanced properties including increased strain at break, higher dielectric constant as well as, gratifyingly, breakdown fields higher than that of the matrix. One of the newly synthesized composites is compared to the commercially available acrylic foil VHB 4905 (3M) which is currently the most commonly used elastomer for DEA applications. It was found that this material has little hysteresis and can be activated at lower voltages compared to VHB 4905. For example, when the newly synthesized composite was 30% prestrained, a lateral actuation strain of about 12% at 40 V μm^?1 was measured while half of this actuation strain at the same voltage was measured for VHB 4905 film that was 300% prestrained. It also survived more than 100 000 cycles at voltages which are close to the breakdown field. Such materials might find applications wherever small forces but large strains at low voltages are required, in, for example, tactile displays.     

长波双色Al_xGa_(1-x)As/GaAs量子阱红外探测器的研制

介绍了长波双色AlxGa1-xAs/GaAs多量子阱红外探测器单元的设计、制作和测试。器件光敏面面积为300μm×300μm,光吸收峰值波长分别为10.8、11.6μm;采用垂直入射光耦合的工作模式,65K温度2V偏压下,两个多量子阱区的暗电流分别为4.23×10-6、4.19×10-6A;黑体探测率分别为1.5×109、6.7×109cm.Hz1/2/W;响应率分别为0.063、0.282A/W。GaAs基量子阱红外探测器(QWIP)材料生长和加工工艺成熟、大面积均匀性好、成本低、不同波段之间的光学串音小,使得AlGaAs/GaAsQWIP在制作多色大面阵方面具有明显的优势。     

Optimization of the dielectric layer for electrowetting on dielectric

In this work the minimum actuation voltage V_min for droplet actuation with electrowetting on dielectric (EWOD) is analyzed. At first, the theoretical background of drop transport with EWOD is shown. Then the impact of thin dielectric films deposited with atomic layer deposition (ALD) and super-hydrophobic layers on the minimum required actuation voltage for drop transport are presented. To this, contact angles are measured on both Al₂O₃ and fluorinated DLC each with a drop of water. For verify the hypothesis, the analytically calculated values for the minimum actuation voltage V_min are compared with numerical simulation results using COMSOL Multiphysics^®. The results show that the actuation voltage value from the simulation is lower than calculated analytically.     

基于变刚度悬臂梁的MEMS静电驱动器的动态响应优化

传统的微机电系统(MEMS)静电驱动器存在驱动电压高和超调振荡的问题,可动极板稳定在平衡位置前会发生持续的振荡,难以满足可变电容、光开关等应用领域的综合要求。针对上述问题,采用变刚度悬臂梁的设计,利用刚度随行程增大的特性抑制了极板吸合及释放过程的振荡现象,在缩短调节时间的同时,有效降低了器件的驱动电压。仿真和实验结果表明,当器件悬臂梁的刚度随位移由5 N/m增大到35 N/m时,在相同电压下,动态响应的调节时间减少了55.5%,在相同行程下,动态响应的调节时间减少了21%,对应的驱动电压减少了23%。     

High voltage electron beam lithography

The advantage of high voltage electron beam lithography in submicron VLSI fabrication is outlined. Continuously-moving-stage EB systems with small deflection width are suited to high voltage electron beam machines. At 50 kV, the following experimental results were obtained:

• 1.(1) 0.75 μm lines of PMMA are formed on a 0.8 μm step.
• 2.(2) Dimension deviation from designed size due to proximity effect is below ±0.1 μm for line or space, ranging from 0.25 μm to 30 μm, adjacent to a large area.
• 3.(3) Dosages, required to obtain a resist pattern with vertical walls, are 50μC/cm² at 50 kV and 100 μC/cm² at 20 kV.
• 4.(4) Accurate position detection for a mark covered with thick overlayers can be achieved at 50 kV, but not at 20 kV.

     

Rapid 3D Printing of Electrohydraulic (HASEL) Tentacle Actuators

A comprehensive material system is introduced for the additive manufacturing of electrohydraulic (HASEL) tentacle actuators. This material system consists of a photo‐curable, elastomeric silicone‐urethane with relatively strong dielectric properties (ε_r ≈ 8.8 at 1 kHz) in combination with ionically‐conductive hydrogel and silver paint electrodes that displace a vegetable‐based liquid dielectric under the application of an electric field. The electronic properties of the silicone material as well as the mechanical properties of the constitutive silicone and hydrogel materials are investigated. The hydraulic pressure exerted on the dielectric working fluid in these capacitive actuators is measured in order to characterize their quasi‐static behavior. Various design features enabled by 3D printing influence this behavior—decreasing the voltage at which actuation begins or increasing the force density in the system. Using a capacitance change of >35% across the actuators while powered, a demonstration of self‐sensing inherent to HASELs is shown. Antagonistic pairs of the 3D printed actuators are shown to exert a blocked force of over 400 mN. An electrohydraulic tentacle actuator is then fabricated to demonstrate the use of this material and actuation system in a synthetic hydrostat. This tentacle actuator is shown to achieve motion in a multi‐dimensional space.     

Investigation of Characteristics of Electrostatically Actuated MEMS Switch with an Active Contact Breaking Mechanism

The electrostatically actuated MEMS switch with resistive contact is presented. The movable electrode is a beam suspended on its torsion hinges. The contact material is platinum. The switch has an active breaking mechanism making it possible to protect it against stiction and provide a low actuation voltage. The measuring technique for the operating characteristic in the “hot” mode under a low direct current is described. The pull-in voltage and the breaking voltage, the switching time, and the dependence of the contact resistance on the number of actuation cycles are measured. The wear of contact surfaces is investigated. The operation of the switch in a bistable mode is demonstrated, in which the closed condition is maintained without applying the actuation voltage and the state transition occurs due to the active contact breaking mechanism.