MEMS mirror device with piezoelectric actuation and manufacturing process thereof

A process of manufacturing a micro-electro-mechanical systems (MEMS) mirror device, comprising:

• forming a fixed structure defining an external frame which delimits a cavity;
• forming a tiltable structure extending into the cavity;
• forming a reflecting surface carried by the tiltable structure and having a main extension in a first plane;
• and
• forming an actuation structure, coupled between the tiltable structure and the fixed structure and configured to cause rotation of the tiltable structure around a first rotation axis parallel to the first plane,
• wherein forming the actuation structure comprises forming at least one first pair of actuation arms and forming elastic coupling elements each elastically coupling a respective first actuation arm of the at least one first pair of actuation arms to the tiltable structure,
• wherein forming the at least one first pair of actuation arms comprises forming a bearing structure and forming a piezoelectric structure, and
• wherein the bearing structure of each actuation arm of the at least one first pair of actuation arms comprises a first region made of a first material and the elastic coupling elements comprise a bearing layer made of a second material, the second material having greater stiffness than the first material.

A MEMS mirror device, comprising:

• a frame encompassing a cavity;
• a mirror element extending into the cavity, rotatable, carrying a reflecting surface in a first plane;
• and
• an actuation component linking the mirror element and the frame;
• the actuation component including at least one pair of actuation arms promoting rotation of the mirror element around an axis parallel to the first plane, the pair of actuation arms being elastically linked to the mirror element via elastic coupling elements, each actuation arm having a bearing structure and a piezoelectric structure, the bearing structure of each actuation arm comprised of a first region made of a first material, and the elastic coupling elements including a bearing layer made of a second material, the second material being stiffer than the first material.