METHOD OF FABRICATING THE RECESS TRENCH FOR RECESS GATE IN SEMICONDUCTOR DEVICE

摘要

A method for forming a recess gate trench in a semiconductor device is provided to prevent the convergence of an electric field at an upper corner of the trench and to improve a breakdown voltage by obtaining a round profile from the trench using a hard mask pattern and a pad oxide pattern as an etch mask. A trench isolation layer for defining an active region is arranged in a semiconductor substrate(50). A pad oxide layer is formed on the active region. A hard mask layer is formed on the pad oxide layer and the trench isolation layer. A hard mask pattern and a pad oxide pattern(90) for exposing partially the substrate to the outside are formed by patterning selectively the hard mask layer and the pad oxide layer. A lateral portion of the pad oxide layer is partially recessed. A recess trench having a round profile is formed on the resultant structure by etching the substrate using the hard mask pattern and the pad oxide pattern as an etch mask.