SILICON CARBIDE SUBSTRATE MANUFACTURING METHOD, SEMICONDUCTOR DEVICE MANUFACTURING METHOD, SILICON CARBIDE SUBSTRATE AND SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a silicon carbide substrate manufacturing method, a semiconductor device manufacturing method, a silicon carbide substrate and a semiconductor device which together make it possible to reduce the manufacturing cost of a semiconductor device using a silicon carbide substrate.SOLUTION: The silicon carbide substrate manufacturing method comprises: a step of preparing a base substrate 10 and a SiC substrate 20; a step of producing a multilayer substrate by stacking the base substrate 10 and the SiC substrate 20 one on top of the other; a step of producing a joined substrate 3 by heating the multilayer substrate; a step of heating the joined substrate 3 so that the temperature of the base substrate 10 is higher than that of the SiC substrate 20, thereby causing voids 30 formed in a junction interface 15 to move in the thickness direction of the jointed substrate 3; and a step of removing a region including a principal plane 10B of the base substrate 10 on the opposite side of the SiC substrate 20 to remove the voids 30.