Process for manufacturing a triaxial piezoresistive accelerometer and relative pressure-monitoring device

A semiconductor piezoresistive accelerometer, comprising:

• a body of semiconductor material;
• a cavity formed in said body;
• a membrane formed in said body and suspended above said cavity;
• an inertial mass fixedly coupled to said membrane;
• and
• piezoresistive transduction elements integrated in said body, sensitive to strains of said membrane and generating corresponding electrical signals;
• wherein said cavity is buried within said body of semiconductor material, and said inertial mass is arranged on top of a surface of said membrane opposite to said cavity.

A pressure-monitoring device, comprising:

• a pressure sensor;
• an electronic circuit connected to said pressure sensor;
• and
• an accelerometer connected to the electronic circuit, the accelerometer including:
• a body of semiconductor material;
• a cavity formed in said body;
• a membrane formed in said body and suspended above said cavity;
• an inertial mass fixedly coupled to said membrane;
• and
• piezoresistive transduction elements integrated in said body, sensitive to strains of said membrane and generating corresponding electrical signals;
• wherein said cavity is buried within said body of semiconductor material, and said inertial mass is arranged on top of a surface of said membrane opposite to said cavity.

An apparatus for monitoring an inflation pressure of a tire of a vehicle, comprising:

• a pressure sensor;
• an electronic circuit connected to said pressure sensor;
• and
• an accelerometer connected to the electronic circuit, the accelerometer including:
• a body of semiconductor material;
• a cavity formed in said body;
• a membrane formed in said body and suspended above said cavity;
• an inertial mass fixedly coupled to said membrane;
• and
• piezoresistive transduction elements integrated in said body, sensitive to strains of said membrane and generating corresponding electrical signals;
• wherein said cavity is buried within said body of semiconductor material, and said inertial mass is arranged on top of a surface of said membrane opposite to said cavity, wherein said pressure sensor measures the inflation pressure of said tire, and said accelerometer measures a centrifugal acceleration caused by rotations of said tire.