Micromechanical component and process for its fabrication

A high-pressure sensor for measuring pressures over 40 bar, comprising:

• at least one cell having:
• a cavity with a given vertical dimension;
• a membrane acting as an electrode of a capacitor of said at least one cell, said membrane homogeneously disposed with a substantially uniform thickness over said cavity, said membrane having a diameter less than 30 μm;
• a counter-electrode of said capacitor disposed under said cavity;
• at least one etching channel laterally adjoining said cavity, said at least one etching channel having a vertical dimension equal to said given vertical dimension;
• and
• at least one closure adjoining said at least one etching channel from above and disposed outside said membrane.

A process for fabricating a micromechanical component, which comprises:

• producing a sacrificial layer over a counter-electrode of a capacitor of a cell;
• structuring the sacrificial layer to fill a region of a cavity to be produced in the cell and to fill an etching channel laterally adjacent to the cavity;
• conformally applying an upper conductive layer over the sacrificial layer;
• producing an opening into the upper conductive layer through the etching channel reaching as far as the sacrificial layer;
• etching the sacrificial layer to produce the cavity, a part of the upper conductive layer disposed over the cavity becoming capable of being deflected and acting as a membrane of the cell and as an electrode of the capacitor;
• and
• closing the etching channel in a region of the opening from above with a closure.