Semiconductor device with buried bitline and method for fabricating the same

Abstract

A method for fabricating a semiconductor device includes forming active regions which are separated by a plurality of first trenches, forming supports which fill the first trenches; etching the active regions and defining second trenches which are shallower than the first trenches, forming spacers on sidewalls of the second trenches, etching bottoms of the second trenches and defining third trenches, forming punch-through preventing patterns which fill lower portions of the third trenches, etching sidewalls which are not protected by the punch-through preventing patterns and the spacers, and forming recessed sidewalls which face each other, and forming buried bit lines in the recessed sidewalls.