A method of producing an infrared sensor on a semiconductor substrate involves defining at least one area on the surface of the semiconductor substrate where a recess is to be created in the semiconductor substrate, depositing a membrane on the surface, applying a radiation absorber to the membrane in the defined area, applying thermoelements with a hot contact in thermal contact with the radiation absorber and a cold contact in thermal contact with the semiconductor substrate. In this method, an opening is provided in the membrane in the defined area, and the semiconductor substrate is etched through the opening.