MEMS device formed by at least two bonded structural layers and manufacturing process thereof

A microelectromechanical device comprising:

• a first substrate having a first recess;
• a second substrate including a microelectromechanical structure, the second substrate having a central portion and a peripheral portion that is separated from the central portion by an opening, the central portion being at the first recess, the second substrate having a second recess in the peripheral portion, the second recess surrounding the central portion;
• and
• a bonding structure in the second recess, the bonding structure coupling the first substrate and the second substrates together.

A microelectromechanical device comprising:

• a first substrate, a microelectromechanical structure formed in the first substrate;
• a second substrate having a first surface facing the first substrate and a second surface opposite the first surface, the second substrate having a first recess surrounding a central portion and extending from the first surface toward the second surface, the first recess being defined by a first planar surface that is a first distance from the second surface, the first recess including a trench that is defined by a second planar surface that is a second distance from the second surface, the second distance being smaller than the first distance;
• and
• a bonding material in the first recess of the second substrate, the bonding material bonding the first substrate to the second substrate such that the microelectromechanical structure formed in the first substrate faces the central portion of the second substrate, the bonding material surrounding the central portion of the second substrate.