Methods and devices for microelectromechanical pressure sensors

A method for post-fabrication of a MEMS device, the method comprising:

• providing the MEMS device comprising (i) a handling layer, (ii) a top layer, and (iii) a device layer located between the handling layer and the top layer, wherein the handling layer comprises a first trench on a top face of the handling layer adjacent to the device layer, wherein the top layer comprises a second trench on a bottom face of the top layer adjacent to the device layer, the second trench facing the first trench, wherein a first portion of the top layer is electrically insulated from a second portion of the top layer, wherein the first portion of the top layer extends to the second trench, wherein the device layer comprises a section of silicon positioned between the first trench and the second trench;
• etching a back face of the handling layer until reaching the first trench, thereby forming an opening extending through the handling layer;
• and
• etching the section of silicon of the device layer through the opening in the handling layer, thereby thinning the section of silicon of the device layer to form a flexible membrane that is (i) positioned between the opening and the second trench and (ii) capacitively coupled with the first portion of the top layer.