Polycrystalline silicon carbide substrate with density gradient and method of manufacturing the same

A method, comprising:

• forming a polycrystalline silicon carbide (SiC) substrate;
• after forming the polycrystalline silicon carbide (SiC) substrate, generating a density gradient between a first side of the polycrystalline silicon carbide (SiC) substrate and a second side of the polycrystalline silicon carbide (SiC) substrate opposite to the first side by motivating mass transport directed in a mass transport direction directed from the first side to the second side of a polycrystalline silicon carbide base substrate opposite to the first side, the motivating the mass transport including:
• exposing the first side of the polycrystalline silicon carbide (SiC) substrate to a first temperature transporting mass away from the first side of the polycrystalline silicon carbide (SiC) substrate;
• exposing the second side of the polycrystalline silicon carbide (SiC) substrate to a second temperature transporting mass toward the second side of the polycrystalline silicon carbide (SiC) substrate, the second temperature being less than the first temperature;
• and
• cooling the polycrystalline silicon carbide (SiC) substrate generating a first density at the first side of the polycrystalline silicon carbide (SiC) substrate, a second density at the second side of the polycrystalline silicon carbide (SiC) substrate greater than the first density, and the density gradient between the first side and the second side of the polycrystalline silicon carbide (SiC) substrate.