Abstract:
A process for manufacturing a microelectromechanical device envisages: forming a semiconductor structural layer (3) separated from a substrate (2) by a dielectric layer (4), and opening trenches (10) through the structural layer (3), as far as the dielectric layer (4). Sacrificial portion (4a) of the dielectric layer (4) are selectively removed through the trenches (10) in membrane regions (M) so as to free a corresponding portion of the structural layer (3) that forms a membrane (11). To close the trenches (10), the wafer (1) is brought to an annealing temperature for a time interval in such a way as to cause migration of the atoms of the membrane (11) so as to reach a minimum energy configuration.