Analytical design of polymer-encapsulated radio frequency microelectromechanical devices

Pejman Monajemi

doi:10.1117/1.JMM.11.2.021207

10 May 2012 Analytical design of polymer-encapsulated radio frequency microelectromechanical devices

Pejman Monajemi

Journal of Micro/Nanolithography, MEMS, and MOEMS, Vol. 11, Issue 2, 021207 (May 2012). https://doi.org/10.1117/1.JMM.11.2.021207

Abstract

An analytical design of radio frequency microelectromechanical (RF MEMS) devices and fabrication and encapsulation results is discussed. The encapsulated MEMS device is an in-plane variable capacitor (varactor), continuously tuned up to 115% at 3.25 V, showing a Q factor of 49 at 1 GHz at zero bias and self-resonance frequency above 5 GHz. The 60-μm-thick device measures 0.6 mm×0.6 mm and is fabricated using high-aspect ratio single-crystal and polysilicon technology, having an air gap of 0.8 μm for tuning and 2 μm for actuation. The effect of gap size, substrate doping, and gold coating on Q is studied. The wafer-level encapsulation is done by the thermal decomposition of a sacrificial polymer through a polymer overcoat at 130°C-150°C, followed by gold evaporation to provide a degree of hermeticity. The overcoat polymer is patterned instead of screen printed, which defines the package boundary, providing a small amount of interconnection. The encapsulated device measures 0.7 mm×0.7 mm, which is only 35% larger than the MEMS device. The insertion loss of the 1 μm/20 μm gold/Avatrel package is measured to be 1.4 dB at 1 GHz and 1.51 dB at 5 GHz, and the calculated nitrogen permeability is less than 1 Barrer. The temperature stability of the rest and the maximum capacitance is better than 7%, in the range of −30-50°C.

Citation Download Citation

Pejman Monajemi "Analytical design of polymer-encapsulated radio frequency microelectromechanical devices," Journal of Micro/Nanolithography, MEMS, and MOEMS 11(2), 021207 (10 May 2012). https://doi.org/10.1117/1.JMM.11.2.021207

Published: 10 May 2012

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available