HIGH INTEGRATED SEMICONDUCTOR DEVICES AND ITS MANUFACTURING METHOD

摘要

The method for preventing a punch-through phenomenon without a variation of threshold voltage increased in accordance with the increase of an integration density comprises forming a trench (15) into a P type substrate (11) to form an isolation film (18) on an inner side of the trench, forming a P type epitaxial layer (19) into the trench to form a P type epitaxial layer (21) and a field oxide film (27), forming a gate oxide film (23) on the second epitaxial layer (21), forming gate electrodes (29) on the gate oxide film such that the isolation film lies halfway between the electrodes, and forming a source and drain regions at the side ends of field oxide film.