TRENCH MOSFET AND METHOD FOR FORMING THE SAME

摘要

A trench Metal-Oxide -Semiconductor Field Effect Transistor (MOSFET) and a method for forming the same are provided. The trench MOSFET includes: a substrate (1); an epitaxial layer (2) formed on the first surface of the substrate (1) and comprising a cell region (12), a gate lead region (18) and a terminal region (13); a well region (3) formed on the epitaxial layer (2); a source region (4) formed on the well region (3); a plurality of trenches formed in the cell region (12) and in the terminal region (13) and extending to the upper surface of the source region (4); a first dielectric layer (5) formed in the trenches; a gate electrode (6) formed on the first dielectric layer (5); a second dielectric layer (8) formed on the source region (4); and a drain metal layer (93) formed on the second surface of the substrate (1). The trenches formed in the terminal region (13) comprise at least two annular trenches. The inner annular trench (10) is an isolating ring applied with zero potential. The outer annular trench (11) is a closing ring and connected with the scribe line (14).