Abstract: A micro-electro-mechanical system (MEMS) device includes a first substrate, an interconnect layer, a MEMS device layer, a stopper and a second substrate. The interconnect layer is disposed on the first substrate and includes a plurality of conductive layers and a plurality of dielectric layer stacked alternately. The MEMS device layer is bonded on the interconnect layer and includes a proof mass. The stopper is disposed directly under the proof mass and spaced apart from the proof mass, where the stopper is surrounded by a portion of the interconnect layer, and the stopper includes a bottom portion constructed of one of the plurality of conductive layers, and a silicon-based layer disposed on the bottom portion. The second substrate includes a cavity and is bonded on the MEMS device layer.