Precursor compositions for atomic layer deposition and chemical vapor deposition of titanate, lanthanate, and tantalate dielectric films
View Patent ↗Barium, strontium, tantalum and lanthanum precursor compositions useful for atomic layer deposition (ALD) and chemical vapor deposition (CVD) of titanate thin films. The precursors have the formula M(Cp) 2 , wherein M is strontium, barium, tantalum or lanthanum, and Cp is cyclopentadienyl, of the formula wherein each of R 1 -R 5 is the same as or different from one another, with each being independently selected from among hydrogen, C 1 -C 12 alkyl, C 1 -C 12 amino, C 6 -C 10 aryl, C 1 -C 12 alkoxy, C 3 -C 6 alkylsilyl, C 2 -C 12 alkenyl, R 1 R 2 R 3 NNR 3 , wherein R 1 , R 2 and R 3 may be the same as or different from one another and each is independently selected from hydrogen and C 1 -C 6 alkyl, and pendant ligands including functional group(s) providing further coordination to the metal center M. The precursors of the above formula are useful to achieve uniform coating of high dielectric constant materials in the manufacture of flash memory and other microelectronic devices.
1. A method of depositing a thin film on a substrate, said method comprising
contacting the substrate with a vapor of a precursor composition, wherein the precursor composition includes a compound of the formula M(Cp) 2 wherein M(Cp) 2 is bis(tetramethyl-n-propylcyclopentadienyl)strontium, and wherein the compound is not coordinated with letrahydrofuran, to form a thin film comprising strontium on the substrate; and
contacting the thin film comprising strontium with an oxidant selected from the group consisting of oxygen, ozone and water.
2. The method according to claim 1 , comprising chemical vapor deposition or atomic layer deposition.
3. The method according to claim 2 , comprising chemical vapor deposition.
4. The method according to claim 2 , comprising atomic layer deposition.
5. The method according to claim 1 , further comprising concurrent or sequential deposition of titanium from a titanium source reagent to produce a titanate film.
6. The method according to claim 5 , wherein the titanate film is strontium titanate.
7. The method according to claim 5 , comprising concurrent deposition.
8. The method according to claim 5 , comprising sequential deposition.
9. The method according to claim 1 , further comprising a solvent medium.
10. The method according to claim 9 , wherein the solvent medium comprises a solvent species selected from the group consisting of C 3 -C 12 alkanes, C 2 -C 12 ethers, C 6 -C 12 aromatics, C 7 -C 16 arylalkanes, C 10 -C 25 arylcycloalkanes, and further alkyl-substituted forms of aromatic, arylalkane and arylcycloalkane species, wherein the further alkyl substituents in the case of multiple alkyl substituents may be the same as or different from one another and wherein each is independently selected from C 1 -C 8 alkyl.
11. The method according to claim 9 , wherein the solvent medium is tetrahydrofuran, xylene, 1,4-tertbutyltoluene, 1,3-diisopropylbenzene, tetrahydronaphthalene, dihydrodimethylnaphthalene, octane or decane.
12. The method according to claim 5 , wherein the oxidant is oxygen or ozone.
13. The method according to claim 12 , wherein the titanate film produced is not annealed.