Semiconductor device with buried bit line and method for fabricating the same

1. A method for fabricating a semiconductor device, the method comprising:

etching a semiconductor substrate to form bulb-type trenches that define a plurality of active regions in the semiconductor substrate;

forming a supporter in each of the bulb-type trenches;

dividing each of the plurality of active regions into a pair of body lines by forming a trench through each of the plurality of active regions; and

forming a bit line in each of the pair of body lines.

2. The method of claim 1 , further comprising:

after forming the bit lines, etching the pair of body lines to form a pair of pillars, where each pillar, of the pair of pillars, includes a channel region; and

forming a capacitor connected to an upper portion of each pillar.

3. The method of claim 1 , wherein the forming of the bulb-type trenches comprises:

etching the semiconductor substrate to form a plurality of first trenches that are defined by sidewalls of the active regions;

forming spacers over the sidewalls; and

etching a surface of the semiconductor substrate that defines the bottoms of the first trenches to form a plurality of bulbs extending in a direction substantially perpendicular to a longitudinal direction of the first trenches.

4. The method of claim 1 , wherein the supporters comprise an insulation material.

5. The method of claim 1 , wherein the forming of the bit lines comprises:

simultaneously etching sidewalls of the pair of body lines which are adjacent to the supporter to form a pair of openings in the sidewalls;

filling the openings with a metal; and

annealing the metal and pair of body lines to produce metal silicide bit lines.