Methods of forming cobalt layers for semiconductor devices
The present invention provides methods of forming cobalt layers on a structure comprising forming a preliminary cobalt layer on a semiconductor substrate by introducing an organic metal precursor onto the semiconductor substrate and treating a surface of the preliminary cobalt layer under an atmosphere of a hydrogen-containing gas to remove impurities contained in the preliminary cobalt layer. Compositions of cobalt layers are also provided. Further provided are semiconductor devices comprising cobalt layers provided herein.
1. A method of forming a cobalt layer, comprising:
forming a first preliminary cobalt layer having a thickness of less than about 200 Å on a semiconductor substrate by exposing a surface of the semiconductor substrate to an organic metal precursor comprising cobalt while simultaneously reacting the organic metal precursor with a first hydrogen-containing gas;
removing impurities from the first preliminary cobalt layer by exposing a surface of the first preliminary cobalt layer to a second hydrogen-containing gas; then
forming a second preliminary cobalt layer on the first cobalt layer by exposing a surface of the first cobalt layer to an organic metal precursor while simultaneously reacting the organic metal precursor with the first hydrogen-containing gas.
2. The method of claim 1 , wherein simultaneously reacting the organic metal precursor with a first hydrogen-containing gas comprises exposing the organic metal precursor to a first hydrogen-containing gas having a temperature in a range between about 100° C. and about 200° C.
3. The method of claim 1 , wherein removing said impurities comprises removing impurities from the first preliminary cobalt layer by exposing a surface of the first preliminary cobalt layer to a second hydrogen-containing gas having a temperature of greater than about 300° C.
4. The method of claim 1 , wherein removing said impurities comprises removing impurities from the first preliminary cobalt layer by exposing a surface of the first preliminary cobalt layer to a second hydrogen-containing gas comprising an inactive element selected from argon, neon, nitrogen and combinations thereof.
5. The method of claim 1 , wherein the semiconductor substrate comprises silicon or a derivative thereof.
6. The method of claim 5 , wherein the semiconductor substrate comprises tungsten suicide, titanium suicide, cobalt suicide or a combination thereof.
7. The method of claim 1 , wherein forming the preliminary cobalt layer and treating the surface of the preliminary cobalt layer are repeatedly performed at least once so as to form a cobalt layer having a desired thickness on the semiconductor substrate.
8. The method of claim 1 , wherein forming the preliminary cobalt layer is carried out by a chemical vapor deposition (CVD) process or an atomic layer deposition (ALD) process.
9. The method of claim 1 , wherein the organic metal precursor comprises carbon, oxygen or a combination thereof.
10. The method of claim 1 , wherein the organic metal precursor is a liquid.
11. The method of claim 1 , wherein the organic metal precursor is Co 2 (CO) 6 :(HC≡CtBu), Co(MeCp) 2 , Co(CO) 3 (NO), Co(CO) 2 Cp, CoCp 2 , Co 2 (CO) 6 :(HC≡CPh), Co 2 (CO) 6 :(HC≡CH), Co 2 (CO) 6 :(HC≡CCH 3 ) or Co 2 (CO) 6 :(CH 3 C≡CCH 3 ) and combinations thereof.
12. The method of claim 1 , wherein the cobalt layer is further subjected to a silicidation process to provide a cobalt silicide layer.
13. The method of claim 1 , wherein the cobalt layer is formed on a semiconductor substrate comprising a contact hole.
14. method of claim 13 further comprising forming a cobalt silicide layer on the gate electrodes and/or portions of the substrate corresponding to contact regions.
15. The method of claim 1 , wherein the cobalt layer is formed on a semiconductor substrate having patterns for gate electrodes.