Mosfet structure with guard ring

A trench MOSFET structure with a guard ring near a termination area for breakdown voltage enhancement, comprising:

• a substrate comprising an epi layer region on a top thereof,
• a plurality of source and body regions formed in the epi layer;
• a metal layer comprising a plurality of metal layer regions which are connected to respective source and body, and trench gate regions forming metal connections of the MOSFET;
• a plurality of contact metal plugs connected to respective metal layer regions;
• a plurality of gate structure filled with polysilicon formed on top of the epi layer;
• an insulating layer deposited on the epi layer formed underneath the metal layer with a plurality of metal contact holes therein for contacting respective source and body regions;
• and
• the guard ring wrapping around the trench gates which have wider trench width than those in active area, and the contact metal plug connecting to the top of the metal layer.