Conference Paper

Back-End-Of-Line Poly-Sige Disk Resonators

Berkeley Sensor and Actuator Center, EECS Dept., University of California
DOI: 10.1109/MEMSYS.2006.1627779 Conference: Micro Electro Mechanical Systems, 2006. MEMS 2006 Istanbul. 19th IEEE International Conference on
Source: IEEE Xplore

ABSTRACT This paper reports the characterization of poly-silicon-germanium disk resonators at frequencies ranging from 35 to 425MHz. The back-end-of-line process technology is based on Spacer definition of sub-100nm lateral gaps, and uses Aluminum as interconnect material for compatibility with advanced CMOS backend. Reported data are organized around transmission, temperature and stability characteristics, as well as scanning-AFM imaging of the radial vibration modes.

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper first discusses the reasons for choosing CMOS-MEMS integration, in particular integration by poly-SiGe processing above CMOS. Next the current state-of-the-art for poly-SiGe MEMS integration and the needs for the future will be addressed. Market trends are translated into two roadmaps for MEMS integration. The first roadmap is based on existing poly-SiGe deposition processes at 400 − 450 ºC. The second roadmap explores processing techniques to lower the thermal budget and widen the application field of MEMS integration by using processing techniques such as metal-induced crystallization, laser annealing or self-assembly.
    MRS Online Proceeding Library 12/2007; 1075. DOI:10.1557/PROC-1075-J05-01
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have developed a novel circularly connected mechanical resonator with rotational symmetry. Its unit resonator design is based on a second-mode free-free beam resonator, suspended by four 1.2 μm narrow support beams. The resonator achieves high quality factors (>10,000) and higher transmissions (>−20 dB) simultaneously in 50 Ω measurement. The frequency range experimentally obtained was from 26 MHz to 195 MHz.The mechanical resonators are completely encapsulated into the cavity. The cavity is vacuumed in aluminum sputtering process and hermetically sealed by aluminum plugs. After the in-line encapsulation, it is possible to handle the proposed resonators as conventional IC chips. In addition, all of the fabrication steps were processed in the conventional CMOS technology.The characteristics of a 45 MHz oscillator were evaluated by using a test circuit board with our 45 MHz resonator chip. The phase noise performance at a 10 Hz offset from the carrier frequency was −40 dBc/Hz and a noise floor was observed at −150 dBc/Hz, demonstrating applicability for practical clock generator circuits.
    Sensors and Actuators A Physical 11/2009; DOI:10.1016/j.sna.2009.03.026 · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Over the past few years, microelectromechanical system (MEMS) based on-chip resonators have shown significant potential for sensing and high frequency signal processing applications. This is due to their excellent features like small size, large frequency-quality factor product, low power consumption, low cost batch fabrication, and integrability with CMOS IC technology. Radio frequency communication circuits like reference oscillators, filters, and mixers based on such MEMS resonators can be utilized for meeting the increasing count of RF components likely to be demanded by the next generation multi-band/multi-mode wireless devices. MEMS resonators can provide a feasible alternative to the present-day well-established quartz crystal technology that is riddled with major drawbacks like relatively large size, high cost, and low compatibility with IC chips. This article presents a survey of the developments in this field of resonant MEMS structures with detailed enumeration on the various micromechanical resonator types, modes of vibration, equivalent mechanical and electrical models, materials and technologies used for fabrication, and the application of the resonators for implementing oscillators and filters. These are followed by a discussion on the challenges for RF MEMS technology in comparison to quartz crystal technology; like high precision, stability, reliability, need for hermetic packaging etc., which remain to be addressed for enabling the inclusion of micromechanical resonators into tomorrow’s highly integrated communication systems.
    Microsystem Technologies 10/2011; 17(10):1557-1580. DOI:10.1007/s00542-011-1332-9 · 0.95 Impact Factor