Method of fabricating flash memory device

1. A method of fabricating flash memory devices, comprising the steps of:

forming a stop nitride film and an oxide film on a semiconductor substrate having a predetermined structure formed therein;

forming trenches defining lateral faces in the oxide film and in the stop nitride film;

forming barrier oxide films on the lateral faces of the trenches by an atomic layer deposition method; and

forming bit lines within the trenches.

2. The method as claimed in claim 1 , wherein the step of forming the trenches comprises the steps of:

forming a tungsten hard mask film on the oxide film;

patterning the tungsten hard mask film; and

etching the oxide film and the stop nitride film using the patterned tungsten hard mask film as a mask.

3. The method as claimed in claim 1 , further comprising the steps of:

forming a contact hole through which a source contact of the predetermined structure is exposed after the barrier oxide films are formed; and

performing a cleaning process.

4. The method as claimed in claim 1 , wherein the barrier oxide films have a thickness of 30 Å to 70 Å.