Fig. 4: MEMS device setup and acoustical as well as optical measurement data
From: Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers
a Assembled device with cover wafer on top showing its acoustic openings; the MEMS chip is glued to a carrier board enabling wire bonds for electrical contacting. The chip actually comprises three different micro speakers, which were not diced for this test set-up. The middle one was used as shown in (a). b Side view of the bonded wafer stack showing the three wafers and their thicknesses. Scallops resulting from cleavage through lacer dicing are clearly visible. c Measurement and modeling results for the SPL. Device was driven with udc = 40 V and uac = 10 Vpp. An SPL of 69 dB was achieved at 500 Hz. d THD measurement and modeling. THD value at 500 Hz is 4.4%. e Sequence of stroboscopic pictures from the holographic microscope showing three consecutive (time wise) deflections states in resonance of one actuator pair (specimen without cover wafer)
