A method for producing at least one cavity within a semiconductor substrate includes dry etching the semiconductor substrate from a surface of the semiconductor substrate at at least one intended cavity location in order to obtain at least one provisional cavity. The method includes depositing a protective material with regard to a subsequent wet-etching process at the surface of the semiconductor substrate and at cavity surfaces of the at least one provisional cavity. Furthermore, the method includes removing the protective material at least at a section of a bottom of the at least one provisional cavity in order to expose the semiconductor substrate. This is followed by electrochemically etching the semiconductor substrate at the exposed section of the bottom of the at least one provisional cavity. A method for producing a micromechanical sensor system in which this type of cavity formation is used and a corresponding MEMS are also disclosed.