Semiconductor structure and manufacturing method thereof

A semiconductor structure comprising:

• a substrate comprising a unit region and a termination region surrounding the unit region, wherein the substrate comprises a first silicon carbide layer and a second silicon carbide layer under the first silicon carbide layer;
• a first guard ring structure in the termination region and in the first silicon carbide layer, the first guard ring structure adjoining a top surface of the first silicon carbide layer, and including at least one first guard ring well region;
• a second guard ring structure in the termination region and in the second silicon carbide layer, the second guard ring structure including at least one second guard ring well region corresponding one-to-one to the at least one first guard ring well region;
• and
• a third guard ring structure in the unit region and in the second silicon carbide layer.

A semiconductor structure comprising:

• a substrate comprising a unit region and a termination region surrounding the unit region, wherein the substrate comprises a first silicon carbide layer and a second silicon carbide layer under the first silicon carbide layer;
• a first guard ring structure in the termination region and in the first silicon carbide layer, the first guard ring structure adjoining a top surface of the first silicon carbide layer, and including at least one first guard ring well region;
• a second guard ring structure in the termination region and in the second silicon carbide layer, the second guard ring structure including at least one second guard ring well region corresponding one-to-one to the at least one first guard ring well region;
• a third guard ring well region in the termination region and in the second silicon carbide layer, the third guard ring well region surrounding the at least one second guard ring well region, with a depth about same as that of the at least one second guard ring well region;
• and
• a compensation well region in the termination region and in the first silicon carbide layer, the compensation well region adjoining the top surface of the silicon carbide layer, a depth of the compensation well region being less than that of the first guard ring structure, and the first guard ring structure being within a coverage of the compensation well region.