Semiconductor device having thin film formed by atomic layer deposition and method for fabricating the same

A semiconductor device comprising:

• a semiconductor substrate in which a trench is formed;
• a liner layer formed on the sidewalls and bottom of the trench;
• a buried insulating layer filled in the trench;
• a plurality of gate stack patterns formed on the semiconductor substrate;
• a plurality of gate spacers formed on the sidewalls of the gate stack patterns;
• a first bubble prevention layer formed of a multi-layer of a silicon oxide layer and a silicon nitride layer on the gate spacers and on the patterned gate stacks by atomic layer deposition;
• a first filling insulating layer filled without a void between the gate stack patterns on the first bubble prevention layer;
• a plurality of bit line stack patterns formed on the first filling insulating layer;
• a plurality of bit line spacers formed on the sidewalls of the bit line stack patterns;
• a second bubble prevention layer formed of a multi-layer of a silicon oxide layer and a silicon nitride layer on the bit line spacers and the bit line stack patterns by atomic layer deposition;
• and
• a second filling insulating layer filled without a void between the bit line stack patterns on the second bubble prevention layer.