射频(rf) mems开关的模拟、制备和力学分析.doc
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射频(rf) mems开关的模拟、制备和力学分析,射频(rf) mems开关的模拟、制备和力学分析 硕士级别论文 约34000字 论述翔实目 录 摘要----------------------------------------------------------------------------------i abstract------------------...
内容介绍
此文档由会员 花季永驻 发布
射频(RF) MEMS开关的模拟、制备和力学分析
硕士级别论文 约34000字 论述翔实
目 录
摘要----------------------------------------------------------------------------------I
Abstract--------------------------------------------------------------------------III
第一章 绪论----------------------------------------------------------------------1
1.1 RF MEMS开关的研究概况---------------------------------------------------------1
1.2本文主要工作--------------------------------------------------------------------------8
第二章 电容型RF MEMS开关的设计与制备---------------------------10
2.1电容型RF MEMS开关的工作原理---------------------------------------------10
2.2设计考虑------------------------------------------------------------------------------12
2.3 RF MEMS开关的制备-------------------------------------------------------------17
2.4本章小结------------------------------------------------------------------------------19
第三章 RF MEMS开关的失效分析---------------------------------------20
3.1 RF MEMS开关的实验测试-------------------------------------------------------20
3.2断裂失效------------------------------------------------------------------------------23
3.3粘着失效------------------------------------------------------------------------------27
3.4残余应力和应力梯度引起的失效------------------------------------------------30
3.5本章小结------------------------------------------------------------------------------33
第四章 RF MEMS开关的力电模型----------------------------------------34
4.1现有的微开关理论模型------------------------------------------------------------34
4.2新的RF MEMS开关力电模型---------------------------------------------------37
4.3基于无量纲数的分析---------------------------------------------------------------41
4.4本章小结------------------------------------------------------------------------------45
i 目录
第五章 RF MEMS开关力电模型的数值模拟----------------------------46
5.1问题描述------------------------------------------------------------------------------46
5.2数值算法的实现---------------------------------------------------------------------48
5.3数值结果分析------------------------------------------------------------------------52
5.4数值结果的拟合---------------------------------------------------------------------58
5.5数值模拟和实验结果的比较------------------------------------------------------62
5.6本章小结------------------------------------------------------------------------------64
第六章 分形粗糙表面的粘着塑性变形------------------------------------65
6.1粘着接触问题介绍------------------------------------------------------------------65
6.2单粗糙峰塑性变形理论------------------------------------------------------------68
6.3塑性变形粗糙表面的粘着接触模型---------------------------------------------69
6.4讨论------------------------------------------------------------------------------------73
6.5本章小结------------------------------------------------------------------------------78
第七章 总结与展望------------------------------------------------------------79
7.1本文总结------------------------------------------------------------------------------79
7.2工作展望------------------------------------------------------------------------------80
附录 A RF MEMS开关阈值电压一阶近似解----------------------------82
附录 B粗糙峰高度分布和粘着数的不同表达式-------------------------84
参考文献--------------------------------------------------------------------------86
攻读硕士期间完成的论文和受到的奖励-----------------------------------93
致谢--------------------------------------------------------------------------------94
ii 摘要
摘 要
由于相对于传统的固体开关，射频微电子机械系统(Radio Frequency Microelectromechanical Systems, RF MEMS)开关具有很多优点，已引起了广泛的关注和研究兴趣。本文分为以下五部分。
第一部分，本文研究的电容型RF MEMS开关由复合膜桥和溅射了传输线的玻璃衬底组成。基于微波、材料和机械设计因素的考虑，这里选择具有高介电常数的Ta2O5作为开关中的介电层，以提高器件的关/开电容比率。为了更好的研究开关的性能，多种不同结构的开关被设计，其中既有直梁结构，也有弯曲梁结构。通过硅玻璃阳极键合和ICP刻蚀技术制备出RF MEMS开关器件。
第二部分，在RF MEMS开关的驱动电压测试和SEM形貌观察时，观察到许多典型的失效现象，经过分析将之归纳为三个主要的失效模式：断裂、粘着、残余应力和应力梯度引起的变形失效。并且对失效模式的失效机制和降低失效的防范措施进行了分析和讨论。
第三部分，综合考虑残余应力、梁轴向伸长、及边缘场效应，建立了关于RF MEMS开关的新的力电模型。通过对模型控制方程的无量纲化，得到四个无量纲数，其中一个表示单位长度梁上的弯曲力和静电力之比，其余三个分别对应于轴向伸长、残余应力和边缘场效应的影响。
第四部分，本文利用一种半解析的数值方法，对前面建立的新模型实现了有效的数值计算。随后，通过数值分析对结构行为中涉及的基本材料参数、几何参数和无量纲数的影响和重要程度分别进行了分析讨论。其中在三个影响因素中，残余应力和梁的轴向伸长相对于边缘场效应要显著的多。并且通过理论、数值和实验结果的比较说明此模型和数值模拟有利于提高理论预测的精确性。
第五部分，对于纳微系统中一个重要的科学问题——表面间的接触问题，本文采用一种更为广泛的表面粗糙高度的描述方式——分形分布，对于固体表面间的粘着塑性接触变形行为进行了研究。得到了实际接触面积、全部载荷和需要的分离力的一般表达式。此分析不再局限于高斯或者指数的分布形式。但是作为特例，对于其中的粗糙因子取1/2和1时，结论将分别退化为已有的高斯分布和指
I 摘要
数分布的情形。
关键词:
微电子机械系统(MEMS),射频(RF) MEMS 开关,键合,阈值电压,吸合,残余应力,边缘场,粘着,分形图形,分离力
II Abstract
Abstract
This thesis includes five parts as follows.
In the first part, Capacitance RF MEMS (Radio Frequency Microelectromechanical Systems) switches are designed and fabricated. The device consists of a composite membrane, suspended over a center conductor, and one gsubstrate sputtered with transmission line. Ta lass 2O5 with high dielectric constant is selected as dielectric layer for high off/on ratio of capacitance. In quest of better performance, various structures are designed, which include straight beam and meander beam. Then the switches are fabricated by silicon-glass bonding and ICP etching technology.
In the second section, during the actuating-voltage testing and SEM observation of RF MEMS switches, many typical failure phenomena are obtained, from which three main failure modes, i.e., fracture, adhesion (stiction) and residual stress and stress gradient induced deformation, are concluded. The associated failure mechanisms are analyzed, and the related approaches to mitigate those failure modes are discussed.
Thirdly, a new electromechanical model of RF MEMS switches is developed, in which the residual stress inherent in microstructure, the axial stretching of movable beam, and the fringing field effect are taken into account. Four dimensionless numbers are derived by making dimensionless of the governing equation of the developed model. One of those dimensionless numbers denotes the ratio of the bending force to the electrostatic force per unit length of beam. The others represent the relative importance of the axial stretching of beam, the residual stress, and the fringing field, respectively.
The fourth part fulfills a valid numerical calculation on the behavior of RF MEMS switches based on the new model mentioned above, using a semi-analytical method. The qualitative relationship and importance between the material and
III Abstract
geometrical parameters on the threshold voltage are achieved, and the corresponding analysis with the dimensionless numbers is conducted too. The residual stress and the axial stretching prove significant in comparison with the fringing effect. The comparison among experiment, theory, and numerical results approves that the developed model and the relevant numerical computation can improve the accuracy of theory.
In the final part of the thesis, since adhesive contact is one of main problems on micro/nano scales, it is required to make more in-depth understanding. A theoretical model is developed to describe the adhesive plastic deformation with fractal distribution of microasperity heights. General expressions of real contact area, total load and the required separation force are obtained. Thus this analysis goes beyond the Gaussian and exponential distributions. As special cases, for 21=α and 1=α, the obtained results can be reduced to those of Gaussian and exponential distributions, respectively.
Key Words: Microelectromechanical Systems (MEMS), Radio Frequency (RF) MEMS switches, Bonding, Threshold voltage, Pull-in, Residual stress, Fringing field, Adhesion (stiction), Fractal geometry, Separation force
部分参考文献
24. 赵亚溥. 智能微系统力学中的几个问题. 石家庄铁道学院学报. 1999, 12(2): 13-18.
25. 余寿文. 复杂微力－电系统的细微尺度力学. 力学进展. 1995, 25(2): 249-259.
26. Park J Y, Kim G H, Chung K W, Bu J U. Monolithically integrated micromachined RF MEMS capacitive switches. Sensors and Actuators. 2001, A 89: 88-94.
27. Osterberg P M, Senturia S D. M-test: a test chip for MEMS material property measurement using electrostatically actuated test structures. J. Microelectromech. Syst. 1997, 6(2): 107-118.
28. De Los Santos H J, Kao Y H, Kaigoy A L, Ditmars E D. Microwave and mechanical considerraions in the design of MEMS switches for aerospace applications. IEEE Aerospace Conference. Snowmass at Aspen, CO, USA. Feb. 1997. 235-253.
29. Pancheo S P, Katehi L P B, Nguyen T C. Design of low actuation voltage RF MEMS switch. Microwave Symposium Digest. 2000 IEEE MTT-S International, 2000. 165-168.
硕士级别论文 约34000字 论述翔实
目 录
摘要----------------------------------------------------------------------------------I
Abstract--------------------------------------------------------------------------III
第一章 绪论----------------------------------------------------------------------1
1.1 RF MEMS开关的研究概况---------------------------------------------------------1
1.2本文主要工作--------------------------------------------------------------------------8
第二章 电容型RF MEMS开关的设计与制备---------------------------10
2.1电容型RF MEMS开关的工作原理---------------------------------------------10
2.2设计考虑------------------------------------------------------------------------------12
2.3 RF MEMS开关的制备-------------------------------------------------------------17
2.4本章小结------------------------------------------------------------------------------19
第三章 RF MEMS开关的失效分析---------------------------------------20
3.1 RF MEMS开关的实验测试-------------------------------------------------------20
3.2断裂失效------------------------------------------------------------------------------23
3.3粘着失效------------------------------------------------------------------------------27
3.4残余应力和应力梯度引起的失效------------------------------------------------30
3.5本章小结------------------------------------------------------------------------------33
第四章 RF MEMS开关的力电模型----------------------------------------34
4.1现有的微开关理论模型------------------------------------------------------------34
4.2新的RF MEMS开关力电模型---------------------------------------------------37
4.3基于无量纲数的分析---------------------------------------------------------------41
4.4本章小结------------------------------------------------------------------------------45
i 目录
第五章 RF MEMS开关力电模型的数值模拟----------------------------46
5.1问题描述------------------------------------------------------------------------------46
5.2数值算法的实现---------------------------------------------------------------------48
5.3数值结果分析------------------------------------------------------------------------52
5.4数值结果的拟合---------------------------------------------------------------------58
5.5数值模拟和实验结果的比较------------------------------------------------------62
5.6本章小结------------------------------------------------------------------------------64
第六章 分形粗糙表面的粘着塑性变形------------------------------------65
6.1粘着接触问题介绍------------------------------------------------------------------65
6.2单粗糙峰塑性变形理论------------------------------------------------------------68
6.3塑性变形粗糙表面的粘着接触模型---------------------------------------------69
6.4讨论------------------------------------------------------------------------------------73
6.5本章小结------------------------------------------------------------------------------78
第七章 总结与展望------------------------------------------------------------79
7.1本文总结------------------------------------------------------------------------------79
7.2工作展望------------------------------------------------------------------------------80
附录 A RF MEMS开关阈值电压一阶近似解----------------------------82
附录 B粗糙峰高度分布和粘着数的不同表达式-------------------------84
参考文献--------------------------------------------------------------------------86
攻读硕士期间完成的论文和受到的奖励-----------------------------------93
致谢--------------------------------------------------------------------------------94
ii 摘要
摘 要
由于相对于传统的固体开关，射频微电子机械系统(Radio Frequency Microelectromechanical Systems, RF MEMS)开关具有很多优点，已引起了广泛的关注和研究兴趣。本文分为以下五部分。
第一部分，本文研究的电容型RF MEMS开关由复合膜桥和溅射了传输线的玻璃衬底组成。基于微波、材料和机械设计因素的考虑，这里选择具有高介电常数的Ta2O5作为开关中的介电层，以提高器件的关/开电容比率。为了更好的研究开关的性能，多种不同结构的开关被设计，其中既有直梁结构，也有弯曲梁结构。通过硅玻璃阳极键合和ICP刻蚀技术制备出RF MEMS开关器件。
第二部分，在RF MEMS开关的驱动电压测试和SEM形貌观察时，观察到许多典型的失效现象，经过分析将之归纳为三个主要的失效模式：断裂、粘着、残余应力和应力梯度引起的变形失效。并且对失效模式的失效机制和降低失效的防范措施进行了分析和讨论。
第三部分，综合考虑残余应力、梁轴向伸长、及边缘场效应，建立了关于RF MEMS开关的新的力电模型。通过对模型控制方程的无量纲化，得到四个无量纲数，其中一个表示单位长度梁上的弯曲力和静电力之比，其余三个分别对应于轴向伸长、残余应力和边缘场效应的影响。
第四部分，本文利用一种半解析的数值方法，对前面建立的新模型实现了有效的数值计算。随后，通过数值分析对结构行为中涉及的基本材料参数、几何参数和无量纲数的影响和重要程度分别进行了分析讨论。其中在三个影响因素中，残余应力和梁的轴向伸长相对于边缘场效应要显著的多。并且通过理论、数值和实验结果的比较说明此模型和数值模拟有利于提高理论预测的精确性。
第五部分，对于纳微系统中一个重要的科学问题——表面间的接触问题，本文采用一种更为广泛的表面粗糙高度的描述方式——分形分布，对于固体表面间的粘着塑性接触变形行为进行了研究。得到了实际接触面积、全部载荷和需要的分离力的一般表达式。此分析不再局限于高斯或者指数的分布形式。但是作为特例，对于其中的粗糙因子取1/2和1时，结论将分别退化为已有的高斯分布和指
I 摘要
数分布的情形。
关键词:
微电子机械系统(MEMS),射频(RF) MEMS 开关,键合,阈值电压,吸合,残余应力,边缘场,粘着,分形图形,分离力
II Abstract
Abstract
This thesis includes five parts as follows.
In the first part, Capacitance RF MEMS (Radio Frequency Microelectromechanical Systems) switches are designed and fabricated. The device consists of a composite membrane, suspended over a center conductor, and one gsubstrate sputtered with transmission line. Ta lass 2O5 with high dielectric constant is selected as dielectric layer for high off/on ratio of capacitance. In quest of better performance, various structures are designed, which include straight beam and meander beam. Then the switches are fabricated by silicon-glass bonding and ICP etching technology.
In the second section, during the actuating-voltage testing and SEM observation of RF MEMS switches, many typical failure phenomena are obtained, from which three main failure modes, i.e., fracture, adhesion (stiction) and residual stress and stress gradient induced deformation, are concluded. The associated failure mechanisms are analyzed, and the related approaches to mitigate those failure modes are discussed.
Thirdly, a new electromechanical model of RF MEMS switches is developed, in which the residual stress inherent in microstructure, the axial stretching of movable beam, and the fringing field effect are taken into account. Four dimensionless numbers are derived by making dimensionless of the governing equation of the developed model. One of those dimensionless numbers denotes the ratio of the bending force to the electrostatic force per unit length of beam. The others represent the relative importance of the axial stretching of beam, the residual stress, and the fringing field, respectively.
The fourth part fulfills a valid numerical calculation on the behavior of RF MEMS switches based on the new model mentioned above, using a semi-analytical method. The qualitative relationship and importance between the material and
III Abstract
geometrical parameters on the threshold voltage are achieved, and the corresponding analysis with the dimensionless numbers is conducted too. The residual stress and the axial stretching prove significant in comparison with the fringing effect. The comparison among experiment, theory, and numerical results approves that the developed model and the relevant numerical computation can improve the accuracy of theory.
In the final part of the thesis, since adhesive contact is one of main problems on micro/nano scales, it is required to make more in-depth understanding. A theoretical model is developed to describe the adhesive plastic deformation with fractal distribution of microasperity heights. General expressions of real contact area, total load and the required separation force are obtained. Thus this analysis goes beyond the Gaussian and exponential distributions. As special cases, for 21=α and 1=α, the obtained results can be reduced to those of Gaussian and exponential distributions, respectively.
Key Words: Microelectromechanical Systems (MEMS), Radio Frequency (RF) MEMS switches, Bonding, Threshold voltage, Pull-in, Residual stress, Fringing field, Adhesion (stiction), Fractal geometry, Separation force
部分参考文献
24. 赵亚溥. 智能微系统力学中的几个问题. 石家庄铁道学院学报. 1999, 12(2): 13-18.
25. 余寿文. 复杂微力－电系统的细微尺度力学. 力学进展. 1995, 25(2): 249-259.
26. Park J Y, Kim G H, Chung K W, Bu J U. Monolithically integrated micromachined RF MEMS capacitive switches. Sensors and Actuators. 2001, A 89: 88-94.
27. Osterberg P M, Senturia S D. M-test: a test chip for MEMS material property measurement using electrostatically actuated test structures. J. Microelectromech. Syst. 1997, 6(2): 107-118.
28. De Los Santos H J, Kao Y H, Kaigoy A L, Ditmars E D. Microwave and mechanical considerraions in the design of MEMS switches for aerospace applications. IEEE Aerospace Conference. Snowmass at Aspen, CO, USA. Feb. 1997. 235-253.
29. Pancheo S P, Katehi L P B, Nguyen T C. Design of low actuation voltage RF MEMS switch. Microwave Symposium Digest. 2000 IEEE MTT-S International, 2000. 165-168.
