Semiconductor device including semiconductor liner and method for fabricating the same
A semiconductor device including: a trench defining an active region in a substrate; a first semiconductor liner formed over the trench; a second semiconductor liner formed over the first semiconductor liner; and a device isolation layer formed over the second semiconductor liner and filling the trench. Disclosed is also a method for fabricating a semiconductor device, the method including: forming a trench defining an active region in a substrate; forming a plurality of semiconductor liners over the trench; performing pretreatment before forming each of the semiconductor liners; and performing post-treatment after forming each of the semiconductor liners.
1. A method for fabricating a semiconductor device, the method comprising:
forming a trench defining an active region in a substrate;
forming a plurality of semiconductor liners over the trench;
performing a pretreatment before forming each of the semiconductor liners;
performing a post-treatment after forming each of the semiconductor liners; and
forming a device isolation layer filling the trench over the plurality of semiconductor liners after performing the post-treatment,
wherein the plurality of semiconductor liners are formed by stacking polysilicon (poly-Si).
2. The method of claim 1 , wherein the performing of the pretreatment comprises:
replacing a contaminant generated before forming each of the semiconductor liners with a sacrificial material; and
performing heat treatment to remove the sacrificial material.
3. The method of claim 2 , wherein the replacing of the contaminant with the sacrificial material is performed using a reactive gas having reactivity with the contaminant.
4. The method of claim 3 , wherein the reactive gas is formed using ammonia (NH 3 ) gas, nitrogen trifluoride (NF 3 ) gas and hydrogen (H 2 ) gas.
5. The method of claim 2 , wherein
the contaminant comprises silicon oxide, and
the sacrificial material comprises ammonium hexafluorosilicate ((NH 4 ) 2 SiF 6 ).
6. The method of claim 1 , wherein the post-treatment is performed at a higher temperature than the pretreatment.
7. The method of claim 1 , wherein the post-treatment is performed through an annealing process or a rapid thermal process (RTP).
8. The method of claim 1 , wherein the post-treatment is performed under a gas atmosphere containing one of nitrogen (N 2 ) and hydrogen (H 2 ).
9. The method of claim 1 , further comprising cleaning each of the semiconductor liners, before the performing of the post-treatment.
10. The method of claim 1 , wherein the pretreatment and the forming of the semiconductor liners are performed in situ.
11. The method of claim 1 , wherein the post-treatment is performed in one of a single equipment and a furnace equipment.
12. A method for fabricating a semiconductor device, the method comprising:
forming a trench defining an active region in a substrate;
performing a first pretreatment in which a native oxide formed on the trench is replaced with a solid salt and the solid salt is sublimated to expose a surface of the trench;
forming a first polysilicon liner over the trench;
performing a post-treatment to remove a contaminant formed on the first polysilicon liner;
performing a second pretreatment in which a native oxide formed on the first polysilicon liner is replaced with a solid salt and the solid salt is sublimated to expose a surface of the first poly silicon liner;
forming a second polysilicon liner over the first polysilicon liner; and
forming a device isolation layer filing the trench over the second polysilicon liner.
13. The method of claim 12 , wherein the replacing of the native oxide with the solid salt is performed using a reactive gas having reactivity with the native oxide.
14. The method of claim 13 , wherein the reactive gas is formed using ammonia (NH 3 ) gas, nitrogen trifluoride (NF 3 ) gas and hydrogen (H 2 ) gas.
15. The method of claim 12 , wherein the solid salt comprises ammonium hexafluorosilicate ((NH 4 ) 2 SiF 6 ).
16. The method of claim 12 , wherein the post-treatment is performed at a higher temperature than the sublimating of the solid salt.
17. The method of claim 12 , wherein the post-treatment is performed through an annealing process or a rapid thermal process (RTP).
18. The method of claim 12 , wherein the post-treatment is performed under a gas atmosphere containing one of nitrogen (N 2 ) and hydrogen (H 2 ).
19. The method of claim 12 , further comprising cleaning the first polysilicon liner, before the performing of the post-treatment.
20. The method of claim 12 , wherein the post-treatment is performed in one of a single equipment and a furnace equipment.