Piezoelectric actuator having a deformation sensor and fabrication method thereof

A microfluidic valve comprising:

• a body;
• a fluidic channel inside the body having a constriction portion defining a passage having a passage section;
• a micro-electromechanical structure (MEMS) actuator including:
• a substrate surrounding a cavity;
• a deformable structure suspended on the cavity;
• a first piezoelectric actuation region of a first piezoelectric material, supported by the deformable structure and configured to cause a deformation of the deformable structure, the first piezoelectric actuation region is coupled to the constriction portion and is configured to modify the passage section;
• and
• a second piezoelectric detection region of a second piezoelectric material, supported by the deformable structure and configured to detect the deformation of the deformable structure;
• and
• a control unit, coupled to the MEMS actuator and configured to provide the first piezoelectric actuation region with a bias voltage and to receive a detection voltage from the second piezoelectric detection region.

A method, comprising:

• controlling a microfluidic valve that includes a fluidic channel having a constriction portion including a passage, a micro-electromechanical structure (MEMS) actuator that has a first piezoelectric actuation region of a first piezoelectric material and a second piezoelectric detection region of a second piezoelectric material, the first piezoelectric actuation region is coupled to the constriction portion and is configured to modify the passage section, and a control unit, coupled to the MEMS actuator;
• providing, by the control unit, the first piezoelectric actuation region with a bias voltage generating a nominal flow in the fluidic channel;
• providing, by the second piezoelectric detection region, the control unit with a detection voltage between a lower detection electrode and a upper detection electrode, the detection voltage corresponding to a measured flow amount;
• comparing an electrical quantity corresponding to the detection voltage with a value corresponding to an amount of the nominal flow;
• and
• applying a new bias voltage in response to the measured flow amount being different from the nominal flow amount.

A method of fabricating a MEMS actuator, comprising:

• forming a cavity and a deformable structure in a substrate of a semiconductor material wafer;
• forming an actuation structure including a first piezoelectric region, of a first piezoelectric material, supported by the deformable structure;
• and
• forming a detection structure including a second piezoelectric region, of a second piezoelectric material, supported by the deformable structure.