Method for fabricating buried gates using pre landing plugs
A method for fabricating a semiconductor device is provided, the method includes forming a plug conductive layer over an entire surface of a substrate, etching the plug conductive layer to form landing plugs, etching the substrate between the landing plugs to form a trench, forming a gate insulation layer over a surface of the trench and forming a buried gate partially filling the trench over the gate insulation layer.
1. A method for fabricating a semiconductor device, comprising:
forming a plug conductive layer over an entire surface of a substrate;
etching the plug conductive layer to form landing plugs;
etching the substrate between the landing plugs to form a trench;
forming a gate insulation layer over the etched substrate;
forming a buried gate over the gate insulation layer to fill a lower portion of the trench; and
forming a sealing layer over the buried gate to fill an upper portion of the trench.
2. The method of claim 1 , further comprising:
forming a contact hole exposing a surface of each of the landing plugs.
3. The method of claim 1 , wherein the sealing layer comprises one selected from the group consisting of an oxide layer, a nitride layer and a double-layered structure comprising a nitride layer and an oxide layer.
4. The method of claim 1 , wherein the plug conductive layer comprises a metal layer or a polysilicon layer.
5. The method of claim 1 , wherein the forming of each of the landing plugs and the trench is performed by using a hard mask layer as an etch barrier.
6. A method for fabricating a semiconductor device, comprising:
forming a device isolation layer in a substrate;
forming a plug conductive layer over an entire surface of the substrate;
etching the plug conductive layer to form landing plugs;
etching the substrate between the landing plugs to form a trench;
forming a gate insulation layer over the etched substrate;
forming a buried gate over the gate insulation layer to fill a lower portion of the trench; and
forming a sealing layer over the buried gate to fill an upper portion of the trench.
7. The method of claim 6 , further comprising:
forming a contact hole exposing a surface of each of the landing plugs.
8. The method of claim 6 , wherein the sealing layer comprises one selected from the group consisting of an oxide layer, a nitride layer and a double-layered structure comprising a nitride layer and an oxide layer.
9. The method of claim 6 , wherein the plug conductive layer comprises a metal layer or a polysilicon layer.
10. The method of claim 6 , wherein the forming of each of the landing plugs and the trench is performed by using a hard mask layer as an etch barrier.