Comparative study of novel micromachined accelerometers employing MIDOS

This paper reports on the fabrication and characterization of a novel imple mentation of micromachined accelerometers. The accelerometers employ a new sensing technique, the modulated integrative differential optical sensing ( MIDOS), to sense the output displacements of their proof-mass. The fabricat ion process of the hybrid device is presented. The device consists of a bul k micromachined mechanical part attached by indium bumps to a CMOS chip con taining photodetectors and readout electronics. Several prototypes were fab ricated and characterized. The differences between the prototypes are discu ssed in detail as well as the comparison between their measured characteris tics (noise equivalent acceleration (NEA), bandwidth and linearity). The pr ototypes have demonstrated NEA ranging from 70 (mu g/root Hz) to 1 (mg/root Hz) with bandwidth of 1 KHz to 4 KHz. (C) 2000 Elsevier Science S.A. All r ights reserved.