Inertial sensor and inertial measurement module

An inertial sensor comprising:

• a substrate;
• a fixed electrode on the substrate;
• a dummy electrode on the substrate, the dummy electrode being spaced apart from the fixed electrode in a plan view;
• a movable body configured to be displaced with respect to the substrate, the movable body directly facing the first fixed electrode and the dummy electrode via a gap in the plan view, the movable body being electrically connected to the dummy electrode such that the movable body and the dummy electrode has a same potential;
• and
• an attenuator configured to attenuate a displacement of the movable body with respect to the substrate, the attenuator being overlapped with only the dummy electrode in the plan view, wherein
• the attenuator includes
• a comb-shaped first structure including a plurality of movable comb fingers whose base ends are coupled to the movable body, and
• a comb-shaped second structure including a plurality of fixed comb fingers whose base ends are coupled to the substrate, the plurality of fixed comb fingers intersecting with the plurality of movable comb fingers, and
• a width of the base end of each of the movable comb fingers and the fixed comb fingers is larger than a width of a tip end thereof.