A sensor chip comprises a substrate (1) with a front side (11) and a back side (12), and an opening (13) in the substrate (1) reaching through from its back side (12) to its front side (11). A stack (2) of dielectric and conducting layers is arranged on the front side (11) of the substrate (1), a portion of which stack (2) spans the opening (13) of the substrate (1). Contact pads (32) are arranged at the front side (11) of the substrate (1) for electrically contacting the sensor chip. A sensing element (4) is arranged on the portion of the stack (2) spanning the opening (13) on a side of the portion facing the opening (13).