Semiconductor device having a recess channel structure and method for manufacturing the same

1. A semiconductor device comprising:

a semiconductor substrate having an active region comprising a gate area, a bit line contact area and a storage node contact area, a recess being formed in the gate area and the bit line contact area;

a gate formed over the gate area, wherein the gate comprises the recess and a portion of an isolation layer, the gate having a main gate in the gate area and a passing gate over the isolation layer,

wherein the main gate comprises a laminate structure of a gate insulation layer formed over a surface of the recess, a first gate conductive layer formed over the gate insulation layer to fill the recess, and a second gate conductive layer and a hard mask layer sequentially formed over the first gate conductive layer, and

wherein the passing gate comprises a laminate structure of a buffer insulation layer, a first gate conductive layer, a second gate conductive layer and a hard mask layer sequentially formed over a surface of the isolation layer;

a first junction area formed in the storage node contact area of the semiconductor substrate;

a second junction area formed in the bit line contact area of the semiconductor substrate, wherein the second junction area formed in the bit line contact area has a lower doping concentration relative to the first junction area formed in the storage node contact area, the lower doping concentration of the second junction area preventing leakage current in the bit line contact area; and

a first landing plug and a second landing plug formed over the first junction area and the second junction area, respectively.

2. The semiconductor device according to claim 1 , wherein the recess has a depth ranging from approximately 500Å to approximately 3000 Å.

3. The semiconductor device according to claim 1 , wherein the first gate conductive layer is formed of a polysilicon layer and the second gate conductive layer is formed of a metal based layer.

4. The semiconductor device according to claim 1 , wherein the first junction area is formed proximate a side surface of the recess and the second junction area is formed below the recess.

5. The semiconductor device according to claim 1 , further comprising cell spacers positioned between the gate and the first landing plug, and between the gate and the second landing plug.

6. The semiconductor device according to claim 5 , further comprising a gate spacer positioned between the gate and the cell spacer, and between the gate and the second landing plug.

7. The semiconductor device according to claim 6 , wherein the gate spacer has a thickness ranging from approximately 10Å to approximately 500 Å.

8. A method for manufacturing a semiconductor device, the method comprising:

forming an isolation layer defining an active region comprising a gate area, a bit line contact area and a storage node contact area in a semiconductor substrate;

forming a buffer insulation layer over the semiconductor substrate including the isolation layer;

performing well ion implantation and channel ion implantation in the active region of the semiconductor substrate formed with the buffer insulation layer;

forming a recess in the gate area and the bit line contact area;

forming a gate material layer to fill the recess;

first etching the gate material layer to expose the hit line contact area:

forming a second junction area in the bit line contact area of the semiconductor substrate;

second etching the gate material layer to form a gate including a main gate in the gate area formed with the recess and a passing gate over the isolation layer, wherein the second etching exposes the storage node contact area;

forming a first junction area in the storage node contact area of the semiconductor substrate, wherein the second junction area formed in the bit line contact area has a lower doping concentration relative to the first junction area formed in the storage node contact area, the lower doping concentration of the second junction area preventing leakage current in the hit line contact area; and

forming a first landing plug and a second landing plug over the first junction area and the second junction area, respectively.

9. The method for manufacturing a semiconductor device according to claim 8 , wherein the buffer insulation layer is formed to a thickness ranging from approximately 10Å to approximately 500 Å.

10. The method for manufacturing a semiconductor device according to claim 8 , wherein the recess is formed to a depth of approximately 500Å to approximately 3000 Å.

11. The method for manufacturing a semiconductor device according to claim 8 , wherein the main gate has a laminate structure comprising a gate insulation layer formed over a surface of the recess, a first gate conductive layer formed over the gate insulation layer to fill the recess, and a second gate conductive layer and a hard mask layer sequentially formed over the first gate conductive layer.

12. The method for manufacturing a semiconductor device according to claim 11 , wherein the first gate conductive layer is formed of a polysilicon layer and the second gate conductive layer is formed of a metal based layer.

13. The method for manufacturing a semiconductor device according to claim 8 , further comprising, after first etching the gate material layer and before forming the second junction area, forming an insulation layer for a gate spacer over the first etched gate material layer.

14. The method for manufacturing a semiconductor device according to claim 13 , wherein the insulation layer is formed to have a thickness ranging from approximately 10Å to approximately 500 Å.

15. The method for manufacturing a semiconductor device according to claim 8 , wherein forming the second junction area is performed with an energy ranging from approximately 5 keV to approximately 500 keV.

16. The method for manufacturing a semiconductor device according to claim 8 , wherein forming the first junction area is performed with an energy ranging from approximately 5 keV to approximately 500 keV.

17. The method for manufacturing a semiconductor device according to claim 8 , wherein the first junction area is formed proximate a side surface of the recess and the second junction area is formed below the recess.

18. The method for manufacturing a semiconductor device according to claim 8 , further comprising, after second etching the gate material layer and before forming the first junction area, forming a cell spacer.