Semiconductor sensor with suspended microstructure and method for fabricating same

摘要

An MISFET type semiconductor sensor, which can avoid deterioration of characteristics, and a method for fabricating same are disclosed. Silicon oxide films and a silicon nitride film are formed on an upper surface of a p-type silicon substrate, and a movable portion is disposed above the silicon nitride film with a predetermined interval interposed therebetween. A movable gate electrode portion exists on a portion of the movable portion and is displaced by acceleration. Fixed electrodes (a source/drain portion) composed of an impurity diffusion layer are formed on the p-type silicon substrate, and a flowing current changes due to a change in a relative position with the movable gate electrode portion due to acceleration. Projections for movable-range restriction use are provided on a lower surface of the movable portion other than the movable gate electrode portion, and form a gap which is narrower than a gap between the p-type silicon substrate and movable gate electrode portion.