Semiconductor device and method of fabricating the same
In a semiconductor device and a method of fabricating the same, the semiconductor device includes a contact pad in a first interlayer insulating layer on a semiconductor substrate, a contact hole in a second interlayer insulating layer on the first interlayer insulating layer, selectively exposing the contact pad, a contact spacer on internal walls of the contact hole, a first contact plug connected to the contact pad exposed by the contact hole having the contact spacer on the internal walls thereof, the first contact plug partially filling the contact hole, a metal silicide layer on a surface of the first contact plug, and a second contact plug on the metal silicide layer and partially filling the remaining portion of the contact hole.
1. A method of fabricating a semiconductor device comprising:
forming a contact pad formed in a first interlayer insulating layer on a semiconductor substrate;
forming a second interlayer insulating layer on the first interlayer insulating layer;
forming a contact hole on the second interlayer insulating layer, the contact hole selectively exposing the contact pad;
forming a contact spacer on internal walls of the contact hole;
forming a first contact plug connected to the contact pad exposed by the contact hole having the contact spacer formed on the internal walls thereof, the first contact plug partially filling the contact hole;
forming a metal silicide layer on a surface of the first contact plug; and
forming a second contact plug formed on the metal silicide layer and partially filling the remaining portion of the contact hole.
2. The method of claim 1 , wherein forming the first contact plug comprises performing a selective epitaxial growth (SEG) process on the contact pad exposed by the contact hole having the contact spacer formed on the internal walls thereof.
3. The method of claim 2 , wherein forming the first contact plug comprises filling at least 5% of the contact hold.
4. The method of claim 3 , wherein the first contact plug is formed to a thickness in a range of about 100 to about 1500 Å.
5. The method of claim 2 , wherein the first contact plug is formed of doped polysilicon.
6. The method of claim 1 , wherein forming the first contact plug comprises:
forming a conductive layer on the second interlayer insulating layer, the conductive layer filling the contact hole having the contact spacer formed on internal walls thereof; and
etching a portion of the conductive layer to allow the portion of the conductive layer to remain in the contact hole having the contact spacer.
7. The method of claim 6 , wherein the etching of the portion of the conductive layer comprises performing an anisotropic etching on the conductive layer.
8. The method of claim 6 , wherein forming the first contact plug comprises allowing at least 5% of the conductive layer to remain in the contact hole.
9. The method of claim 6 , wherein the first contact plug is formed to a thickness in a range of about 100 to about 1500 Å.
10. The method of claim 6 , wherein the first contact plug is formed of doped polysilicon.
11. The method of claim 1 , wherein forming the metal silicide layer comprises:
forming a metal barrier layer conformally along the contact hole on the first contact plug; and
performing an annealing process to form the metal silicide layer.
12. The method of claim 1 , wherein forming the second contact plug comprises burying a metal layer on the metal silicide layer.
13. The method of claim 1 , wherein the contact spacer is formed of a nitride layer.
14. The method of claim 1 , after forming the contact pad, further comprising forming an outer spacer surrounding external walls of an upper portion of the contact pad.