Method of fabricating semiconductor device

1. A method of fabricating a semiconductor device, comprising steps of:

forming as part of a substrate a trench, a gate insulating film, and a poly gate on the substrate;

forming a nitride film on the substrate;

forming an LDD region in the substrate and beneath the nitride film by ion implantation using the poly gate as a mask;

forming an oxide film on at least a portion of the nitride film on side portions of the poly gate;

etching the oxide film to form a gate sidewall;

ion implanting impurities in the substrate to form a source/drain using the gate and the sidewall as masks;

vapor depositing PMD over the substrate including the gate sidewalls and the nitride film so as to form an upper layer and then planarizing the upper layer;

etching the PMD to form a contact hole to the LDD region; and

vapor depositing a barrier metal on the PMD, treating with heat, and filling up the contact hole.

2. The method of claim 1 , wherein the step of forming a nitride film includes forming a film having a thickness in an inclusive range of 200 through 500 Å.

3. The method of claim 1 , wherein the step of forming the oxide film includes forming a film having a thickness in an inclusive range of 500 through 2000 Å.

4. The method of claim 1 , wherein the step of vapor depositing PMD includes forming a film having a thickness in an inclusive range of 4000 through 10000 Å.

5. The method of claim 1 , wherein the step of vapor depositing the barrier metal comprises using TiN, and one of Ti and Co.