US Patent 7939886 Trench gate power semiconductor device

A trench gate power MOSFET (1) includes: an n−-type epitaxial layer (12); a p-type body region (20) formed in the vicinity of an upper surface of the n−-type epitaxial layer (12); a plurality of trenches (14) formed so as to reach the n−-type epitaxial layer (12) from an upper surface of the p-type body region (20); and gates (18) formed in the trenches (14). In some regions facing the p-type body region (20) in the n−-type epitaxial layer (12), p-type carrier extracting regions (26a, 26b, 26c) are formed. According to the trench gate power MOSFET (1), holes generated in a cell region can be effectively collected through the p-type carrier extracting regions (26a, 26b, 26c) so as to further increase a speed of the switching operation.