MEMS devices and methods for forming the same are provided. A first metal interconnect structure is formed on a first semiconductor substrate to connect to a CMOS control circuit in the first semiconductor substrate. A bonding layer having a cavity is formed on the first metal interconnect structure, and then bonded with a second semiconductor substrate. A conductive plug passes through a first region of the second semiconductor substrate, through the bonding layer, and on the first metal interconnect structure. A second metal interconnect structure includes a first end formed on the first region of the second semiconductor substrate, and a second end connected to the conductive plug. Through-holes are disposed through a second region of the second semiconductor substrate and through a top portion of the bonded layer that is on the cavity to leave a movable electrode to form the MEMS device.