Abstract: A semiconductor substrate includes a base portion, an auxiliary layer and a surface layer. The auxiliary layer is formed on the base portion. The surface layer is formed on the auxiliary layer. The surface layer is in contact with a first main surface of the semiconductor substrate. The auxiliary layer has a different electrochemical dissolution efficiency than the base portion and the surface layer. At least a portion of the auxiliary layer and at least a portion of the surface layer are converted into a porous structure. Subsequently, an epitaxial layer is formed on the first main surface.

Abstract: A method for operating a magnetostrictive displacement measuring device, having a wave guide for guiding at least one mechanical wave, at least one damping zone, a magnetic position encoder which is displaceably arranged along a measuring range of the position measuring device and a detection unit, generates the at least one mechanical wave by an excitation signal (IP) having a clock frequency (f1, f2), at least two mechanical waves having respectively different clock frequencies (f1, f2, f) being generated. The clock frequencies can be predetermined such that interfering reflections (R11, R12) occur at different positions (x11, x21, x2) of the measuring range of the displacement measurement device, and during the method of the position encoder, switching between the different clock frequencies (f1, f2, f) takes place, such that the interfering reflections (R11, R12) on the respective different positions (x11, x21, x22) of the measuring range are masked out.

Abstract: A method for operating a magnetostrictive displacement measuring device, having a wave guide for guiding at least one mechanical wave, at least one damping zone, a magnetic position encoder which is displaceably arranged along a measuring range of the position measuring device and a detection unit, generates the at least one mechanical wave by an excitation signal (IP) having a clock frequency (f1, f2), at least two mechanical waves having respectively different clock frequencies (f1, f2, f) being generated. The clock frequencies can be predetermined such that interfering reflections (R11, R12) occur at different positions (x11, x21, x2) of the measuring range of the displacement measurement device, and during the method of the position encoder, switching between the different clock frequencies (f1, f2, f) takes place, such that the interfering reflections (R11, R12) on the respective different positions (x11, x21, x22) of the measuring range are masked out.