High-voltage device and method of forming the same

A method of forming a high-voltage device, comprising:

• providing a substrate;
• forming an epitaxial layer on the substrate;
• forming a first high-voltage well region, a first deep well region encircling the first high-voltage well region, and a second high-voltage well region encircling the first deep well region in a first region of the epitaxial layer;
• forming a first doped region and a second doped region encircling the first doped region in the first high-voltage well region;
• forming a third doped region in the first deep well region, wherein the third doped region encircles the second doped region;
• forming a fourth doped region in the second high-voltage well region;
• forming a fifth doped region and a sixth doped region in a second region of the epitaxial layer, wherein the second region laterally adjoins the first region;
• extending a side of the fourth doped region outward into a third region of the epitaxial layer to form a loop, wherein the second region is in the loop;
• forming a second deep well region in the loop, wherein the second deep well region extends along an inner side of the loop and across the second region;
• forming a seventh doped region in the second deep well region, wherein the seventh doped region extends along a profile of the second deep well region;
• and
• cutting off a portion of the seventh doped region in the second deep well region across the second region.