TRENCHED POWER MOSFET AND MANUFACTURING METHOD THEREOF

摘要

A trenched power MOSFET includes: an N-type substrate (1) and an N-type epitaxial layer (2) growing on the substrate (1); a P-well region (10) formed on the epitaxial layer (2), a source region (11) formed over the P-well region(10) and a first oxide layer (12) covering the source region (11); a P+ injected region (15) located in the P-well region (10) under the source region (11); which characterized in that: including many trenches which punch through the source region (11) and the P-well region (10) and contact the epitaxial layer (2),wherein the bottom trenches have a thick oxide layer (16) with thickness of 0.15-0.25µm; a method of manufacturing the trenched power MOSFET is provided. The trenched power MOSFET reduces the gate-drain capacitance of the MOSFET in the case of not affecting the threshold voltage of the MOSFET, thus improving its switching speed.