Piezoelectric MEMS device with a suspended membrane having high mechanical shock resistance and manufacturing process thereof

An electronic apparatus, comprising:

• an application-specific integrated circuit (ASIC);
• a memory block;
• an input/output interface;
• a microprocessor electrically coupled to the ASIC, the memory block, and the input/output interface;
• and
• a microelectromechanical system (MEMS) device coupled to the ASIC and including:
• a body having a first surface and a second surface, the body having a support portion and a deformable portion supported by the support portions extending between the first surface and a cavity that extends in the body from the second surface, the deformable portion including:
• a stiffening element including:
• an end in the cavity;
• a stiffening layer including a sidewall at the end, the sidewall is transverse to the first and second surfaces;
• and
• a coating layer between the stiffening layer and the support portion, the coating layer covering the sidewall of the stiffening layer;
• a piezoelectric actuator extending over the first surface of the body, on the deformable portion;
• wherein the deformable portion has a first region with a first thickness in a thickness direction and a second region with a second thickness greater than the first thickness, in the thickness direction, the second region being adjacent to the first region of the deformable portion and being adjacent to the support portion of the body.

A microelectromechanical system (MEMS) device, comprising:

• a central axis;
• a substrate including a first surface, a second surface opposite to the first surface, and a wall that is transverse to the first and second surfaces and that extends from the first surface to the second surface;
• a deformable portion including:
• a stiffening element on the second surface of the substrate, the stiffening element including:
• a stiffening layer including a sidewall spaced apart from the wall of the substrate, the sidewall of the stiffening layer is closer to the central axis than the wall;
• a coating layer on the sidewall of the stiffening layer and between the stiffening layer and the second surface of the substrate;
• a deformable element that extends inward from the stiffening element towards the central axis;
• a cavity delimited by the deformable portion and the substrate, the cavity extends into the first surface of the substrate to the deformable portion;
• and
• a piezoelectric actuator on the deformable portion, the piezoelectric actuator at least partially overlaps the stiffening element.