LAUSR

Through the use of a laser Doppler vibrometer, it is shown that a 31% variation in quality factor can occur due to the effect of undercutting of the device layers outside of the anchors of a 220-MHz aluminum nitride contour-mode resonator. This undercutting is a result of the isotropic etch process used to release the device from the substrate. This paper shows that the variation in $Q$ is a function of the release distance, $L$ , between the active region of the resonator and the edge of this released region. This paper also determined a design modification that eliminated this issue and achieved a $Q$ of 3048, which is independent of $L$ .