Method for fabricating ultrathin diaphragm-based capacitive pressure sensor

Provided is a method for fabricating an ultrathin diaphragm-based capacitive pressure sensor, comprising: forming at least one ultrathin diaphragm (1a) on a lining substrate (2); forming an insulation film (3), provided with at least one cavity (31) etched therein; attaching the ultrathin diaphragm (1a) and a substrate (4) respectively to two end surfaces of the insulation film (3), so as to seal the cavity (31); removing the lining substrate (2); and conducting electric charges on the ultrathin diaphragm (3) and the substrate (4) via two bonding pads (5). A pressure sensor having extremely small dimensions can still achieve high sensitivity by using the ultrathin diaphragm as a sensitive film. Moreover, the substrate serving as a lower electrode can support the insulation film and the ultrathin diaphragm, and the insulation film and the ultrathin diaphragm are connected by bonding or direct growth of films, thereby having remarkably high structural stability.