Semiconductor integrated capacitive acceleration sensor and relative fabrication method

摘要

The acceleration sensor is formed in a monocrystalline silicon wafer (4) forming part of a dedicated SOI substrate (50) presenting a first (1) and second (4) monocrystalline silicon wafer separated by an insulating layer (2) having an air gap (3). A well (15) is formed in the second wafer (4), over the air gap (3), and is subsequently trenched up to the air gap to release the monocrystalline silicon mass (23) forming the movable mass (24) of the sensor; the movable mass (24) has two numbers of movable electrodes (28a, 28b) facing respective pluralities of fixed electrodes (29a, 29b). In the idle condition, each movable electrode (28) is separated by different distances from the two fixed electrodes (29) facing the movable electrode.