Semiconductor device including zener diode ring and manufacturing method of forming the same

A manufacturing method of forming a semiconductor device, the manufacturing method comprising:

• providing a semiconductor substrate and disposing an epitaxial layer on the semiconductor substrate, the semiconductor substrate having a silicon carbide layer;
• forming a current spreading layer to define an active area and a periphery area surrounding the active area;
• conducting a first implant process to a front surface of the epitaxial layer to form a doped layer;
• forming a field oxide layer on the epitaxial layer by a field oxide deposition process;
• forming a polysilicon layer on the field oxide layer by a gate polysilicon deposition process;
• conducting a second implant process to the polysilicon layer to form a plurality of P-plus regions and a plurality of N-plus regions, the plurality of P-plus regions and the plurality of N-plus regions at the periphery area being alternatively arranged;
• etching the plurality of P-plus regions and the plurality of N-plus regions to define a zener diode at the periphery area and a polysilicon gate at the active area, wherein doped ring regions of the plurality of P-plus regions and the plurality of N-plus regions are each formed in a ring shape with rounded corners;
• forming a dielectric layer by an interlayer dielectric deposition process to cover the zener diode and the polysilicon gate;
• etching the dielectric layer to form a first contact hole at the active area and two second contact holes at the periphery area, wherein the doped ring regions of the plurality of P-plus regions and the plurality of N-plus regions are each configured to surround one second contact hole among the two second contact holes connected to a source metal, the doped layer is configured to be exposed by the first contact hole, and the polysilicon layer is configured to be exposed by each of the two second contact holes;
• forming a metal contact layer by a metal deposition process, the metal contact layer being etched to define the source metal and a gate metal, the source metal electrically connecting to the doped layer through the first contact hole, the source metal and the gate metal electrically connecting to the zener diode through the respective ones of the second contact holes, and wherein an inner ring of the plurality of N-plus regions is configured to be connected to the one second contact hole among the two second contact holes connected to the source metal, and an outer ring of the plurality of N-plus regions is configured to be connected to one other second contact hole among the two second contact holes connected to the gate metal.