MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To suppress hump phenomenon and parasitic effect of current with a semiconductor element by, after flattening an element isolation oxide film of a trench, etching the element separation oxide film by a specified thickness, and by selectively performing side wall ion implantation process on the area affecting the operation of a parasitic transistor. SOLUTION: A pad oxide film a nitride film are vapor deposited on an Si substrate 11, and, with a nitride film pattern 15 patterned for limitation to an active area and a non-active area and a pad oxide film pattern 13 as a mask, the Si substrate 11 of the non-active area is selectively etched in anisotropic manner, for a trench 17 to be formed. An oxide film is grown all over the trench 17, to prevent damage. The trench 17 is buried in an insulation film, thus an element isolation oxide film 27 is formed. The element separation film 27 is etched in anisotropic manner by specified thickness, and with the nitride film pattern 15 as a mask, ion implantation is performed on the side surface of the trench 17. After the nitride film pattern 15 is removed. The ion implantation for well formation and threshold voltage regulation is performed, thus a gate electrode 19 is formed.