A method of manufacturing a semiconductor substrate includes providing a semiconductor wafer having a first surface and a second surface opposite the first surface, and forming, when seen in a cross-section perpendicular to the first surface, cavities in the semiconductor wafer at a first distance from the first surface. The cavities are laterally spaced from each other by partition walls formed by semiconductor material of the wafer. The cavities form a separation region. The method further includes forming a semiconductor layer on the first surface of the semiconductor wafer, and breaking at least some of the partition walls by applying mechanical impact to the partition walls to split the semiconductor wafer along the separation region.