SEMICONDUCTOR DEVICE HAVING TRENCH STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device having trench structure capable of preventing threshold voltage Vth in the corners of a trench from being reduced without increasing ON resistance. SOLUTION: A MOSFET 10 is provided with an n+-type semiconductor substrate 11, an n-type 1st semiconductor layer 12 is formed on the main surface of the substrate 11, and a p-type 2nd semiconductor layer 13 is formed on the upper surface of the 1st semiconductor layer 12. An n+-type 3rd semiconductor layer 14 is formed on a part of the surface layer part of the 2nd semiconductor layer 13. The trench 15 dividing the 2nd semiconductor layer 13 into a plurality of sections and having corners is formed like a grating from the surface of the 3rd semiconductor layer 14 so as to reach the 1st semiconductor layer 12 through a part of the 2nd semiconductor layer 13. A gate oxide film 16 is formed on the inwall surface of the trench 15, and gate electrodes G are formed so as to fill the trench 15. In order to form transistor areas having high threshold voltage on respective corner parts of the trench 15, p+-type areas 17 are formed. COPYRIGHT: (C)2004,JPO