Investigation of charging characteristics in the dielectric for RF MEMS switches and Preparation of silicon-based MEMS infrared emitter

第一部分：射频微电子机械（RFMEMS）开关电介质充放电特性调查 RFMEMS电容开关在商业、航空和军事领域有巨大的应用前景.。然而，它们的商业化一直受阻于可靠性问题：电介质充电效应引起开关致动部分发生不可逆的粘连现象。在本论文中，我们使用金属－电介质－半导体（MIS）结构去调查开关电介质层电荷积累的问题。通过对MIS结构施加电压负载，然后测量电容－电压（C-V）曲线的变化，我们能够研究电介质的充放电特性。对氮化硅(SiNx)介质进行直流电压负载并测量了C-V实验数据，我们得到SiNx介质的充电特性如下： ·硅悬健具有两性性质，它们可以被正的或负的充电； ·来自开关金属桥的电荷注入是引起...First part: Investigation of charging characteristics in the dielectric for RF MEMS switches RF MEMS capacitive switches hold great promise in commercial aerospace and military applications. However, their commercialization is hindered by reliability concerns: charging effect in the dielectric layer can cause irreversible stiction of the actuating part of the switch. In this thesis, a Metal-Insul...学位：博士后院系专业：物理与机电工程学院物理学系_半导体物理与器件学号：DH1700017

MEMS hybrid power-generator from vibration energy

介绍了一种结合了压电式能量采集与静电式能量采集原理的复合式振动能量采集器。其结构通过有限元分析软件的优化设计,得到了期望的低频共振频率。为了预测这个复合式振动能量采集器的性能,建立了解析模型,在此基础上使用MATlAb/SI MulInk进行了数值模拟。模拟结果显示,在某些特定的频率范围内,这种复合式振动能量采集器能够提供比其他两种能量采集器更高的输出功率。对于固有频率为282 Hz的器件结构,仿真发现复合式设计的输出功率可达4.85μW,两倍于电容式设计的输出功率2.11μW。A hybrid vibration-powered microgenerator has been presented by combining the structures of piezoelectric generator and electrostatic generator,and the structure of the microgenerator is optimized by a Finite Element Method(FEM) to obtain the desired low resonant frequency.Then,an analytic model is established to predict the behavior of the hybrid power-generator and a MATLAB/SIMULINK is utilized for the numerical simulation.The simulated results reveal that the hybrid power-generator has a higher output power than those of two energy harvesting mechanisms at a special resonant frequency.For a resonant frequency of 282 Hz,the simulation result shows the output power from the hybrid mechanism is 4.85 μm,which doubles 2.11 μW from the original capacitive mechanism.SupportedbytheNationalNaturalScienceFoundationofChina(GrantNo.50575191);theScienceandTechnologyProgramofXiamen(GrantNo.3502Z20063006

Modeling and experiment of large-scale principle prototype based on piezoelectric

为了实现环境振动能量的低频收集,分析了压电式振动能量收集技术的特点,并建立了其数学模型。利用数值分析软件对能量收集器的性能进行了仿真模拟,压电式能量收集器更适用于低频环境下的能量收集。成功制造了具有四根环形悬臂梁结构的大尺寸原理样机,实验得到了在外界0~500 Hz低频扫频下,不同加速度激励下的开路电压、负载电阻的电压输出,并与理论分析结果对比。In order to harvest low-frequency vibration energy of environment,analyze characterstics of piezoelectric vibration energy harvesting technology,and set up math model.Simulation on property of energy harvester is carried out by numerical analysis software,prototype with four annular cantilevers is made.Theoretical and experimental models are presented.Based on state space equations,numerical analysis are performed.Opencircuit voltage and voltage output load resistance at different accelerations of low-frequency 0 ~ 500 Hz vibration sources are obtained by experiment and the experimental result is compared to theoretical result.国家自然科学基金资助项目(51075344;61274120

聚乙烯基硅氮烷微球的合成及陶瓷化

采用沉淀共聚合方法制备了聚乙烯基硅氮烷腈(PVSZ)微球。其中乙烯基环硅氮烷与二乙烯基苯为共单体,偶氮二异丁腈(AIBN)为引发剂,乙腈为溶剂。聚合反应12h制备的微球表面光滑,粒径为700 nm~780 nm,分散性良好。能量色谱(EDS)证明微球包含Si、C、N元素;红外光谱(FT-IR)表明微球化学结构是PVSZ;微球1000℃热解,陶瓷产率为35%。热解温度低于1300℃时,PVSZ微球的热解产物能完整地保持球形结构、表面光滑;X射线衍射(XRD)表明产物呈非晶态;热解温度1500℃时,球形结构破坏,产物结晶,生成了Si3N4晶粒

基于一维TiO2纳米管阵列薄膜的β伏特效应研究

介绍了一种采用宽禁带半导体二氧化钛纳米管阵列薄膜材料制备β伏特效应同位素电池的方法.通过对金属钛片的电化学阳极氧化制备了垂直定向、有序排列的二氧化钛纳米管阵列薄膜,研究了退火条件对二氧化钛纳米管阵列薄膜半导体光电性能的影响.通过与镍-63辐射源的集成封装,形成三明治结构镍-63/二氧化钛纳米管阵列薄膜/钛片的β伏特同位素电池.实验结果表明,基于氩气氛围下450?C退火的黑色二氧化钛纳米管阵列薄膜具有高的氧空位缺陷浓度和宽的可见-紫外吸收光谱.在使用β辐射总能量为10 m Ci的镍-63辐射源时,同位素电池的开路电压为1.02 V,短路电流75.52 n A,最大有效转换效率为22.48%.国家自然科学基金(批准号:61574117);;深圳市科技计划项目(批准号:JCYJ20170306141006600)资助的课题~

MEMS Infrared Emitter Based on SOI Wafer

提出了一种利用微机电系统(MEMS)制造工艺技术制备的硅基微型红外光源。该光源使用绝缘体上硅(SOI)晶片作为基底材料,其上沉积多晶硅材料并通过离子注入工艺实现材料的电阻加热发光特性,SOI晶片上的单晶硅层通过重掺杂实现辐射光背向吸收自加热效应。利用SOI晶片中的掩埋二氧化硅层为刻蚀停止层,通过背面深反应离子刻蚀(drIE)技术制备微米量级的薄膜发光层结构。光源表面工作温度和辐射光谱分别通过红外热像仪和光谱辐射计测量得到。实验结果表明,该光源在表面温度约700 k时,1.3--14.5μM波长内的能量转换效率约为5.58%,光源的调制频率在50%的调制深度下接近40 Hz。A micro-electro-mechanical systems(MEMS) infrared(IR) emitter is presented.The IR emitters are fabricated on silicon-on-insulator(SOI) wafer,and the resistance heating film on the SOI wafer used boron-doped polysilicon by ion implantation technology.The single crystal silicon on SOI wafer is designed as a heavily-doped infrared absorption layer for realizing the self-heating effect.The light-emitting layer is fabricated by using deep reactive ion etching(DRIE)process on the backside of SOI wafer,and the buried SiO2 layer of the SOI wafer is used as etching stop layer to control the thickness of light-emitting layer.The surface temperature and emission spectrum of IR emitter are measured by thermal imaging system and spectroradiometer.The experimental results show that in the case of surface temperature of about 700 K,the energy conversion efficiency is about 5.58% in the spectrum range of 1.3--14.5 μm.The experiments also show that the modulation frequency can reach to 40 Hz at 50% modulation depth.航空科学基金(20080868011;20080868009)资助课

Silicon-glass-based single piezoresistive pressure sensors for harsh environment applications

National Natural Science Foundation of China [51075344, 61274120, 51175444]; Fujian Province Major Projects on University-Industry Cooperation in Science and Technology [2013H6023]; Science and Technology Program of Xiamen [3502Z20123008, 3502Z20126006]Silicon-glass (Si-glass)-based single piezoresistive pressure sensors were designed and fabricated by standard MEMS technology. The single piezoresistive sensing element was designed to be on the lower surface of the silicon diaphragm and be vacuum-sealed in a Si-glass cavity, which form a self-packaging protection structure helpful to the applications of sensors in harsh media. The pressure sensors were fabricated using a Si-glass anodic bonding technique, and the embedded Al feedthrough lines at the Si-glass interface are used to realize the electrical connections between the piezo-sensing element and the electrode-pads, and two larger-size electrode-pads are fabricated for realizing the soldered electrical connection between the sensor and the external circuit. The performance of the pressure sensors was characterized by a pressure test system at different temperature conditions. The temperature compensation was performed by the difference between the output voltage at zero-pressure and the output at operation pressure. The measurement results show that the sensitivity is 24 mV V-1 MPa-1, the coefficient of sensitivity is 0.14% FS degrees C-1, and both the zero-point offset and the temperature coefficient of offset are equal to zero, which are able to meet the commercial application requirements. However, a nonlinearity of 5.2% FS caused by the balloon effect would considerably worsen the accuracy of the pressure sensor. It is suggested to reduce the balloon effect by using a bossed-diaphragm structure in the pressure sensor

A Facile Route to Construct SiCO Nanospheres with Tunable Sizes

Natural Science Foundation of China [51175444, 51075344, 61274120]; Fundamental Research Funds for the Central Universities (Xiamen University) [2011121002]; Xiamen Municipal Bureau of Science and Technology [3502Z20126006]; Shenzhen City Science and Technology Innovation Committee [JCYJ20120618155425009]; National Science and Technology Major Project of the Ministry of Science and Technology of China [2011ZX02709-002]We report a facile route to synthesize SiCO nanospheres using Pluronic F127/ polyvinylsilazane (PVSZ) mixed micelles as a template, in which PVSZ selectively swells with the PEO core of the F127 micelles. The thermal degradation of the F127/ PVSZ mixed micelles leads to the formation of SiCO nanospheres. The size of the resultant SiCO nanospheres can be tuned in the range from 25 nm to 75 nm by controlling annealing time at 70 degrees C

Preparation and Characterization of Hydrophobic SiO_2-glass Fibers Aerogels via Ambient Pressure Drying

以正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)为复合硅源,玻璃纤维为增强体,采用溶胶-凝胶和常压干燥工艺制备出疏水性SIO2-玻璃纤维复合气凝胶。利用n2吸附脱附、扫描电镜、高分辨透射电镜、红外光谱、接触角、热重-差热分析及力学测试等手段表征复合气凝胶,并分析预处理玻璃纤维时的盐酸浓度及浸泡时间对复合气凝胶密度的影响。结果表明:当玻璃纤维的预处理条件为2.5MOl/l盐酸浸泡0.5H时,制备得到的SIO2-玻璃纤维复合气凝胶表观密度最低,为0.12g/CM3,孔径主要分布在2~50nM,疏水角为142°,热稳定性温度高达500℃,抗压强度为0.05MPA,弹性模量为0.5MPA。Hydrophobic SiO2-glass fibers aerogels were prepared by sol-gel process with tetraethoxysiliane(TEOS)and methyltriethoxysilane(MTES)as the silica source,glass fibers as reinforcement,followed by ambient pressure drying.The physical properties and microstructure of silica aerogels were characterized by nitrogen adsorption/desorption tests,Fourier transform infrared spectroscopy,thermogravimetric and differential thermal analysis,scanning electron microscopy,high resolution transmission electron microscopy,contact angle measurement and mechanical testing.The influences of acid concentration and soaking time during pretreatment of glass fibers on the densities of SiO2-glass fibers aerogels were investigated.The results show that when the pretreatment condition of glass fibers is soaking 0.5hat 2.5mol/L hydrochloric acid,the obtained monolithic SiO2-glass fibers aerogels exhibit the lowest density of 0.12g·cm-3 and pore size is in the range of 2-50 nm,the water contact angle is 142°,the thermal stability temperature reaches 500℃,the compressive strength is0.05 MPa,and the elastic modulus is 0.5MPa.国家自然科学基金资助项目(51175444;61274120); 中央高校(厦门大学)基本科研业务费专项资金资助项目(2011121002); 航空科学基金资助项目(2013ZD68009); 福建省高等学校新世纪优秀人才支持计划资助项目(2013); 福建省自然科学基金资助项目(2014J01206); 厦门市科技计划资助项目(3502Z20143009