Semiconductor device using piezoelectric actuator formed by use of MEMS technique

A semiconductor device comprising:

• a first electrode,
• a second electrode arranged in opposition to the first electrode to at least partly overlap the first electrode, a capacitance of a capacitor between the first and second electrodes varying according to a variation in an overlapping amount between the first and second electrodes, and
• an actuator which drives at least one of the first and second electrodes to change an overlapping amount between the first and second electrodes,
• wherein the actuator has a first beam portion which is formed to extend in a first direction with one end fixed at a substrate by use of a supporting member and warped by residual stress with the supporting member set as a starting point,
• a piezoelectric portion which is connected at one end to the other end of the first beam portion and formed to extend in a second direction intersecting with the first direction and moves parallel to the substrate in the first direction and in a direction opposite to the first direction by application of bias voltage, and
• a second beam portion which is connected at one end to the other end of the piezoelectric portion, formed to extend in a direction opposite to the first direction, connected at the other end to one of the first and second electrodes and warped in the same direction as the first beam portion by residual stress.

A semiconductor device comprising:

• a sheet-form member formed on a substrate, and
• a plurality of actuators which drive the sheet-form member in a direction parallel to the surface of the substrate,
• wherein each of the plurality of actuators has a first beam portion which is formed to extend in a first direction with one end thereof fixed at the substrate by use of a supporting member and warped by residual stress with the supporting member set as a starting point,
• a piezoelectric portion which is connected at one end to the other end of the first beam portion and formed to extend in a second direction intersecting with the first direction and moves parallel to the substrate in the first direction and in a direction opposite to the first direction by application of bias voltage, and
• a second beam portion which is connected at one end to the other end of the piezoelectric portion, formed to extend in a direction opposite to the first direction, connected at the other end to one of the first and second electrodes and warped in the same direction as the first beam portion by residual stress.