METHOD FOR FABRICATING TRENCH CAPACITOR OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method is for fabricating a trench capacitor of a semiconductor device having higher electrostatic capacity than a trench of an equal depth by forming a pillar in the trench. CONSTITUTION: A method for fabricating a trench capacitor includes the steps of: forming a hard mask by depositing and patterning a nitride film(120) and a first oxide film(130) on a semiconductor substrate(110); forming a subsidiary mask comprising a second oxide film and a sacrificial film on the semiconductor substrate revealed by the pattern of the hard mask; after removing the sacrificial film, forming a trench in the center by etching the second oxide film and the semiconductor substrate with the nitride film and the first oxide film as a mask; forming a third oxide film doped with impurity, and then forming an outer electrode(200) of the capacitor through the diffusion of the doped impurity; forming a capacitor insulation film(210) on an inner wall of the trench; and forming an inner electrode(220) of the capacitor by filling a conductive material in the trench where the capacitor insulation film is formed.