Investigation of charge accumulation in the dielectric for robust RF MEMS switches

For higher-power-handling RF MEMS switches, the design of the switch is based on fixed-fixed beam capacitive structure with electrostatic actuation. Such RF MEMS switches are perceived to be unreliable because of the stiction and screening of the beam caused by charge accumulation in the dielectric layer. The research effort for a robust RF MEMS solution has been made for more than a decade. In this paper the models for stiction and screening caused by charge accumulation have been reviewed. As the first part of this paper, the possible charging mechanisms will be described, such as, 1) the dielectric charging arises from charges distributed throughout the dielectric material, 2) the presence of charges at the dielectric interface. In order to avoid the charge accumulation, trapped charges in the dielectric layer have to quickly vanish. Relaxing mechanisms of short time must be created inside of the dielectric for quick charge recombination. The second part of this paper will report the recent effort to create relaxing mechanisms of short time by using, such as doping dielectric, nano-composite dielectrics, or multi-layer stack of dielectric. Actuation wave form dependence of the charge accumulation will be also presented.

[1]  Patrick Pons,et al.  Charging-Effects in RF capacitive switches influence of insulating layers composition , 2006, Microelectron. Reliab..

[2]  W. De Raedt,et al.  Analytical Model of the DC Actuation of Electrostatic MEMS Devices With Distributed Dielectric Charging and Nonplanar Electrodes , 2007, Journal of Microelectromechanical Systems.

[3]  H.G.A. Huizing,et al.  Characterization of dielectric charging in RF MEMS capacitive switches , 2006, 2006 IEEE International Conference on Microelectronic Test Structures.

[4]  R. Plana,et al.  Modeling of the dielectric charging kinetic for capacitive RF-MEMS , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[5]  Steven T. Patton,et al.  Effects of dielectric charging on fundamental forces and reliability in capacitive microelectromechanical systems radio frequency switch contacts , 2006 .

[6]  R. Dutton,et al.  Characterization of contact electromechanics through capacitance-voltage measurements and simulations , 1999 .

[7]  J. Cazaux,et al.  Reliability modeling of capacitive RF MEMS , 2005, IEEE Transactions on Microwave Theory and Techniques.

[8]  G. Papaioannou,et al.  Temperature study of the dielectric polarization effects of capacitive RF MEMS switches , 2005, IEEE Transactions on Microwave Theory and Techniques.

[9]  Robert Puers,et al.  Impact of biasing scheme and environment conditions on the lifetime of RF-MEMS , 2005 .

[10]  W. De Raedt,et al.  Distributed dielectric charging and its impact on RF MEMS devices , 2004, 34th European Microwave Conference, 2004..

[11]  C. Goldsmith,et al.  Acceleration of Dielectric Charging in RF MEMS Capacitive Switches , 2006, IEEE Transactions on Device and Materials Reliability.

[12]  Michael Hietschold,et al.  Parasitic charging of dielectric surfaces in capacitive microelectromechanical systems (MEMS) , 1998 .

[13]  J. R. Reid.  Simulation and Measurement of Dielectric Charging in Electrostatically Actuated Capacitive Microwave Switches , 2001 .

[14]  Gabriel M. Rebeiz.  RF MEMS: Theory, Design and Technology , 2003 .

[15]  George J. Papaioannou,et al.  Effect of space charge polarization in radio frequency microelectromechanical system capacitive switch dielectric charging , 2006 .

[16]  David Dubuc,et al.  Failure predictive model of capacitive RF-MEMS , 2005, Microelectron. Reliab..

[17]  Robert Puers,et al.  A comprehensive model to predict the charging and reliability of capacitive RF MEMS switches , 2004 .

[18]  J.C.M. Hwang,et al.  Modeling and characterization of dielectric-charging effects in RF MEMS capacitive switches , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[19]  Jean-Philippe Polizzi,et al.  Lifetime characterization of capacitive RF MEMS switches , 2005, SPIE MOEMS-MEMS.

[20]  P. T. Lai,et al.  Conduction mechanisms in MOS gate dielectric films , 2004, Microelectron. Reliab..

[21]  Xuefeng Zhuang,et al.  A solution to the charging problems in capacitive micromachined ultrasonic transducers. , 2005, IEEE transactions on ultrasonics, ferroelectrics, and frequency control.

[22]  J. Papapolymerou,et al.  On the dielectric polarization effects in capacitive RF-MEMS switches , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[23]  M. Alonso,et al.  Fundamental University Physics , 1967 .

[24]  R. Plana,et al.  Investigation of Stiction Effect in Electrostatic Actuated RF MEMS Devices , 2007, 2007 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems.

[25]  C.L. Goldsmith,et al.  Initial observation and analysis of dielectric-charging effects on RF MEMS capacitive switches , 2004, 2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535).

[26]  J.R. Reid,et al.  Noncontact measurement of charge induced voltage shift in capacitive MEM-switches , 2003, IEEE Microwave and Wireless Components Letters.

[27]  C. Goldsmith,et al.  High-Cycle Life Testing of RF MEMS Switches , 2007, 2007 IEEE/MTT-S International Microwave Symposium.

[28]  James C. M. Hwang,et al.  Dielectric Charging of RF MEMS Capacitive Switches under Bipolar Control-Voltage Waveforms , 2007, IMS 2007.

[29]  S. Marshall,et al.  Electromagnetic concepts and applications , 1982 .

[30]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[31]  Luis Castañer,et al.  Dielectric charge measurements in capacitive microelectromechanical switches , 2006 .

[32]  Zhen Peng,et al.  A transient SPICE model for dielectric-charging effects in RF MEMS capacitive switches , 2006, IEEE Transactions on Electron Devices.

[33]  J. R. Reid,et al.  Measurements of charging in capacitive microelectromechanical switches , 2002 .

[34]  J. Schmitz,et al.  Time and voltage dependence of dielectric charging in RF MEMS capacitive switches , 2007, 2007 IEEE International Reliability Physics Symposium Proceedings. 45th Annual.

[35]  Marcelo Alonso,et al.  Fundamental university physics. Volume 2, Fields and waves , 1970 .

[36]  David Dubuc,et al.  Investigation of charging mechanisms in metal-insulator-metal structures , 2005, Microelectron. Reliab..