Electromechanical microsytems with air gaps

The present invention relates to an microelectromechanical system (1) comprising: a base (15) comprising a substrate (20) and a substrate electrode (40); a moveable beam (30); a voltage generator (10) able to generate a potential difference between the beam (30) and the substrate electrode (40); and at least one mechanical stop (70) connected to the beam and designed to make contact with the base (15) when a potential difference is applied between the beam (30) and the substrate electrode (40), thereby defining an air-filled cavity (80) between the beam (30) and the substrate electrode (40), characterized in that it furthermore comprises an electrical-charge blocking element (50) placed on the substrate (20), said element facing the at least one mechanical stop (70) and being electrically connected to the beam (30).