Lanthanum compound, method of synthesizing lanthanum compound, lanthanum precursor composition, method of forming thin film, and method of manufacturing integrated circuit device

1. A compound of the following Chemical Formula 1:

wherein R 1 is a C1-C4 linear or branched alkyl group, and each R X is independently a C1-C2 alkyl group.

2. The compound as claimed in claim 1 , wherein the compound is pure.

3. A method of forming the compound as claimed in claim 1 , the method comprising:

reacting a lanthanum tris(alkylsilylamide) complex with an alkylcyclopentadiene, wherein:

in the lanthanum tris(alkylsilylamide) complex, the alkyl groups are each independently a C1-C2 alkyl group, and

in the alkylcyclopentadiene, the alkyl group is a C1-C4 linear or branched alkyl group.

4. The method as claimed in claim 3 , further comprising purifying the resultant of the reaction of the lanthanum tris(alkylsilylamide) complex with the alkylcyclopentadiene.

5. The method as claimed in claim 4 , wherein the purifying includes sublimation of the compound represented by Chemical Formula 1.

6. A method of manufacturing an integrated circuit (IC) device using the compound as claimed in claim 1 , the method comprising:

forming a lower structure on a substrate; and

forming a lanthanum-containing film on the lower structure, the lanthanum-containing film being produced by deposition of lanthanum-containing species from a composition that includes the compound represented by Chemical Formula 1 and a compound represented by the following Chemical Formula 2:

wherein, in Chemical Formula 2, R 1 is a C1-C4 linear or branched alkyl group, each of R 2 and R 3 is independently a C1-C4 linear or branched alkyl group, and R 4 is hydrogen or a methyl group.

7. A synthesis method, the method comprising:

synthesizing a silicon-containing intermediate of Chemical Formula 1 by reacting a lanthanum tris[bis(trialkylsilyl)amide] complex with an alkylcyclopentadiene,

wherein R 1 is a C1-C4 linear or branched alkyl group, and each R X is independently a C1-C2 alkyl group; and

synthesizing a lanthanum compound of Chemical Formula 2 by reacting the silicon-containing intermediate of Chemical Formula 1 with a dialkylamidine-based compound,

wherein R 1 is a C1-C4 linear or branched alkyl group, each of R 2 and R 3 is independently a C1-C4 linear or branched alkyl group, and R 4 is hydrogen atom or a methyl group.

8. The method as claimed in claim 7 , wherein in the silicon-containing intermediate of Chemical Formula 1, R X is a methyl group.

9. The method as claimed in claim 7 , wherein the lanthanum compound of Chemical Formula 2 is a liquid at room temperature.

10. The method as claimed in claim 7 , wherein the dialkylamidine-based compound is formed from diisopropyl acetamidine.

11. The method as claimed in claim 7 , wherein in the lanthanum compound of Chemical Formula 2, R 1 is an ethyl group, each of R 2 and R 3 is an isopropyl group, and R 4 is a methyl group.

12. The method as claimed in claim 7 , wherein in the lanthanum compound of Chemical Formula 2, each of R 1 , R 2 , and R 3 is an isopropyl group, and R 4 is a methyl group.

13. The method as claimed in claim 7 , wherein in the lanthanum compound of Chemical Formula 2, R 1 is an isopropyl group, each of R 2 and R 3 is a t-butyl group, and R 4 is a methyl group.

14. The method as claimed in claim 7 , further comprising, before the synthesizing of the silicon-containing intermediate, synthesizing the lanthanum tris[bis(trialkylsilyl)amide] complex by reacting a lanthanum halide with a bis(trialkylsilyl)amide alkali metal salt.

15. The method as claimed in claim 14 , wherein the lanthanum halide is LaCl 3 .

16. The method as claimed in claim 14 , wherein the bis(trialkylsilyl)amide alkali metal salt includes sodium (Na), lithium (Li), or potassium (K).