INTEGRATED CAPACITIVE SENSOR FOR MECHANICAL QUANTITIES, AND MANUFACTURING METHOD

摘要

1. Integrated capacitive sensor for mechanical quantities, comprising a monolithic semiconductor substrate (14) equipped with a first electrode (17) ; a flexible plate (1) which is produced in a material not entirely metallic, which defines a free space (19) with the substrate (14) and which is liable to undergo small displacements, in order to alter slightly the relative position of the plate (1) with respect to the substrate in the absence of resonance from the plate ; a second electrode (2) place on the face of plate (1) opposite said free space (19) and means for detecting a significant electric signal representing variations in the position of said plate (1), characterized in that said means for detecting a significant electric signal comprise first and second zones of diffusion of source (4) and of drain (5), which zones are not contiguous but separated by a channel (6) and formed in parallel to the plate (1) in the upper part of the substrate (14), and electrodes (34, 35) connected, respectively, to the source zone (4) and to the drain zone (5), in such a way as to create a structure of semiconductor insulating metal type of which the movable electrode (2) constitutes the gate, and in that the free space (19), situated between the plate (1) and the substrate (14), has a thickness ranging between about 0.2 and 3 mu m, and preferably in the region of 1 mu m.