Novel pure‐metal tri‐axis CMOS‐MEMS accelerometer design and implementation

Abstract

Abstract This work proposed a pure‐metal, single‐proof‐mass structure fabricated by the standard 0.18 μm one‐poly‐silicon six‐metal (1P6M) CMOS process along with one in‐house post‐CMOS wet‐etching approach. The implemented state‐of‐the‐art symmetrical tri‐axis accelerometer consists of the disk‐like mezzanine proof‐mass and four diagonal double‐layered springs. Three sets of the addressable quadrant electrodes underneath the proof‐mass with additional interlayer inter‐digital comb‐conductors help to fulfil the high sensibilities of 248.6, 250.8, and 220.1 mV/G for the x‐, y‐, and z‐axes, respectively. Symmetrical‐structure and addressable‐electrode design of the device also effectively eliminates the cross‐coupling effects. The thin‐film composite springs can be width‐trimmed for the necessities of specification changes, and the optional calibration pads also provide the on‐chip accuracy compensations. The fabricated tri‐axis accelerometer reveals stable and consistent results and exemplifies a potential platform design for the highly integrated monolithic CMOS‐MEMS system‐on‐chip applications.

Keywords

• Surface treatment (semiconductor technology)
• CMOS integrated circuits
• Design and modelling of MEMS and NEMS devices
• Fabrication of MEMS and NEMS devices
• Sensing devices and transducers
• Velocity, acceleration and rotation measurement