Semiconductor device with buried bit line and method for fabricating the same
A semiconductor device includes an active body having two sidewalls facing each other in a lateral direction, a junction formed in a sidewall of the two sidewalls, a dielectric layer having an open portion to expose the junction and covering the active body, a junction extension portion having a buried region to fill the open portion, and a bit line coupled to the junction extension portion.
1. A semiconductor device comprising:
an active body having two sidewalls facing each other in a lateral direction;
a junction formed in a sidewall of the two sidewalls;
a dielectric layer having an open portion to expose the junction and covering the active body;
a junction extension portion coupled with the junction through the open portion and having a trench therein; and
a bit line formed on the trench of the junction extension portion,
wherein the junction extension portion comprises a polysilicon layer, and the bit line comprises a titanium nitride (TiN) layer.
2. The semiconductor device of claim 1 , wherein the junction extension portion comprises a silicon layer.
3. The semiconductor device of claim 1 , wherein the junction extension portion comprises an impurity-doped polysilicon layer.
4. The semiconductor device of claim 1 , wherein the junction and the junction extension portion have impurities doped therein, the impurities having the same conductive type.
5. The semiconductor device of claim 1 , wherein the bit line comprises a metal layer or a metal nitride layer.
6. The semiconductor device of claim 1 , further comprising:
an active pillar formed over the active body;
a word line formed on sidewalls of the active pillar and extended in a direction crossing the bit line; and
a capacitor coupled to an upper portion of the active pillar.