[796]

Abstract-Free-free-beam flexural-mode micromechanical resonators utilizing nonintrusive supports to achieve measured s as high as 8400 at VHF frequencies from 30 to 90 MHz are demonstrated in a polysilicon surface micromachining technology. The microresonators feature torsional-mode support springs that effectively isolate the resonator beam from its anchors via quarter-wavelength impedance transformations, minimizing anchor dissipation and allowing these resonators to achieve high-with high stiffness in the VHF frequency range. The free-free-beam micromechanical resonators of this paper are shown to have an order of magnitude higher than clamped-clamped-beam versions with comparable stiffnesses.[499]

A technology has been demonstrated that uses compression bonding to modularly combine platform-supported µmechanical filters with integrated BiCMOS transistor circuits while attempting to preserve the Q of mounted resonators. In this process, µmechanical devices are first fabricated onto SOI platforms, which are then released (together with devices) and compression bonded onto a transistor circuit wafer, making electrical connections at the bonds. Prior to bonding, while mounted on unreleased platforms, 6 MHz and 40 MHz clamped-clamped beam µmechanical resonators exhibit Q's of 2,000 and 300, respectively. After release and bonding to the circuit wafer, the Q's are degraded to 520 and 120, respectively. Poor bonding quality is identified as a likely reason for the observed Q reductions.

No abstract