Silicon carbide substrate, epitaxial wafer and manufacturing method of silicon carbide substrate

A manufacturing method of a silicon carbide substrate comprising the steps of:

• preparing a base substrate having a main surface and made of silicon carbide;
• washing said main surface using a first alkaline solution;
• washing said main surface using a second alkaline solution after the step of washing using said first alkaline solution,
• the main surface of the base substrate is etched after washing the main surface using the second alkaline solution;
• an average of residues on the main surface being etched are between 0.2 and 5 in number, and
• the residues include at least one of an abrasive liquid and a fixing agent for fixing the silicon carbide substrate during polishing, the residues are measured by obtaining an average of values determined from five-point measurement within a visual field with sides of 50 μm, and when a visual field with sides other than 50 μm is used, the obtained values are converted into those corresponding to the sides of 50 μm.