Deposition methods using heteroleptic precursors
An ALD method includes exposing a substrate to a first precursor including a plurality of different ligands, chemisorbing a precursor monolayer on the substrate, and reacting a second precursor with the precursor monolayer to yield a product monolayer. A surface reactive ligand exhibits a chemisorption affinity that exceeds the chemisorption affinity exhibited by a gas reactive ligand. Another deposition method includes exposing a substrate to a precursor containing an amino and/or imino ligand and a halide ligand and depositing a layer. The precursor exhibits a volatility that exceeds the volatility with a halide ligand taking the place of each amino and/or imino ligand. The precursor exhibits a thermal stability that exceeds the thermal stability with an amino and/or imino ligand taking the place of each halide ligand. The layer may exhibit less halogen content than with a halide ligand taking the place of each amino and/or imino ligand.
1. An ALD method comprising:
providing a deposition substrate and exposing the substrate to a first precursor including a metal or a semimetal and a plurality of different ligands, a surface reactive ligand of the first precursor exhibiting a chemisorption affinity for the substrate that exceeds the chemisorption affinity exhibited by a gas reactive ligand of the first precursor;
chemisorbing a precursor monolayer on the substrate using the first precursor;
reacting a second precursor with the precursor monolayer, modifying the precursor monolayer, and yielding a product monolayer consisting essentially of the metal, the semimetal, or an oxide, nitride, silicide, sulfide, or selenide of the metal or semimetal.
2. The method of claim 1 wherein the gas reactive ligand of the first precursor remains as a gas reactive ligand of the precursor monolayer after the chemisorbing.
3. The method of claim 2 wherein reacting the second precursor with the precursor monolayer comprises reacting the second precursor with the gas reactive ligand.
4. The method of claim 1 wherein the gas reactive ligand exhibits a thermal stability that exceeds the thermal stability exhibited by the surface reactive ligand.
5. The method of claim 1 wherein the plurality of ligands comprises ketoiminate and/or amidinate.
6. The method of claim 1 wherein the second precursor consists of at least one of O 2 , O 3 , Si 2 H 6 , NH 3 , SiH 4 , H 2 O, N 2 H 4 , H 2 O 2 , NO, N 2 O, H 2 S, SO 3 , SO 2 , H 2 Se, H 2 , B 2 H 6 , NH 2 R, and NHR 2 , where R is organic or silylorgano.
7. An ALD method comprising:
providing a deposition substrate and exposing the substrate to a first precursor including a metal or a semimetal and a plurality of different ligands, a surface reactive ligand of the first precursor exhibiting a chemisorption affinity for the substrate that exceeds the chemisorption affinity exhibited by a gas reactive ligand of the first precursor;
chemisorbing a precursor monolayer on the substrate using the first precursor, the gas reactive ligand of the first precursor exhibiting a thermal stability that exceeds the thermal stability exhibited by the surface reactive ligand and the gas reactive ligand remaining as a gas reactive ligand of the precursor monolayer after the chemisorbing; and
reacting a second precursor with the gas reactive ligand of the precursor monolayer, modifying the precursor monolayer, and yielding a product monolayer consisting essentially of the metal, the semimetal, or an oxide, nitride, silicide, sulfide, or selenide of the metal or semimetal.
8. The method of claim 7 wherein exposing the substrate to the first precursor occurs in the substantial absence of the second precursor and reacting the second precursor with the precursor monolayer occurs in the substantial absence of any first precursor vapor.
9. The method of claim 7 wherein the surface or gas reactive ligand consists of NR 2 and/or NR, where R is H, alkyl, aryl, or silyl.
10. The method of claim 7 wherein both the surface and gas reactive ligands are anionic.
11. The method of claim 7 wherein the first precursor is ionically neutral.
12. The method of claim 7 wherein the plurality of ligands consists of at least two of the following ligands: amino, imino, halide, pseudohalide, diketonate, alkoxide, ketoiminate, amidinate, carboxylate, cyclopentadienyl, hydrido, alkyl, and a neutral ligand.
13. The method of claim 12 wherein the amino and imino ligands comprise, respectively, dialkylamino and alkylimino ligands.
14. The method of claim 12 wherein the neutral ligand comprises alkene, diene, cyclic diene, triene, alkyne, CO, and NO ligands.
15. The method of claim 7 wherein the first precursor comprises bis(tert-butoxy) bis(dimethylhexanedionato)hafnium, the surface reactive ligand is tert-butoxy, and the gas reactive ligand is dimethylhexanedionato.
16. The method of claim 7 wherein the metal or semimetal is selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten.
17. The method of claim 7 wherein the second precursor comprises at least one of O 2 , O 3 , Si 2 H 6 , NH 3 , SiH 4 , H 2 O, N 2 H 4 , H 2 O 2 , NO, N 2 O, H 2 S, SO 3 , SO 2 , H 2 Se, H 2 , B 2 H 6 , NH 2 R, and NHR 2 , where R is organic or silylorgano.
18. The method of claim 7 wherein the substrate comprises a bulk semiconductor wafer.
19. An ALD method comprising:
providing a deposition substrate and exposing the substrate to an ionically neutral first precursor in the substantial absence of a second precursor, the first precursor including a metal and a plurality of different ligands, a surface reactive ligand of the first precursor exhibiting a chemisorption affinity for the substrate that exceeds the chemisorption affinity exhibited by a gas reactive ligand of the first precursor, and the plurality of ligands including ketoiminate and/or amidinate;
chemisorbing a precursor monolayer on the substrate using the first precursor, the gas reactive ligand of the first precursor exhibiting a thermal stability that exceeds the thermal stability exhibited by the surface reactive ligand and the gas reactive ligand remaining as a gas reactive ligand of the precursor monolayer after the chemisorbing; and
reacting the second precursor with the gas reactive ligand of the precursor monolayer in the substantial absence of any first precursor vapor, modifying the precursor monolayer, and yielding a product monolayer consisting essentially of the metal or an oxide, nitride, silicide, sulfide, or selenide of the metal, the second precursor including at least one of O 2 , O 3 , Si 2 H 6 , NH 3 , SiH 4 , H 2 O, N 2 H 4 , H 2 O 2 , NO, N 2 O, H 2 S, SO 3 , SO 2 , H 2 Se, H 2 , B 2 H 6 , NH 2 R, and NHR 2 , where R is organic or silylorgano.
20. A deposition method comprising:
providing a deposition substrate;
exposing the substrate to a precursor consisting of at least one amino ligand and/or imino ligand, a metal or a semimetal, and at least one halide ligand; and
depositing over the substrate a layer including the metal, the semimetal, or an oxide, nitride, silicide, sulfide, or selenide of the metal or semimetal, the layer exhibiting less halogen content than otherwise exhibited with a halide ligand taking the place of each amino ligand and/or imino ligand.
21. The method of claim 20 wherein the precursor exhibits a volatility that exceeds the volatility otherwise exhibited with a halide ligand taking the place of each amino ligand and/or imino ligand.
22. The method of claim 20 wherein the precursor exhibits a vapor pressure of greater than 0.1 Torr at less than or equal to 120° C.
23. The method of claim 20 wherein the precursor exhibits a thermal stability that exceeds the thermal stability otherwise exhibited with an amino ligand and/or imino ligand taking the place of each halide ligand.
24. The method of claim 20 wherein the precursor consists of a halide amino metal.
25. The method of claim 20 wherein the precursor is ionically neutral and consists of X z-y M(NR 2 ) y , where X is halogen, M is metal, z is the valence of M, R is alkyl, aryl, or silyl, and y is at least 1.
26. The method of claim 25 wherein z is 4, 5, or 6 and y is 1 to 5.
27. The method of claim 20 wherein the precursor consists of a halide imino metal.
28. The method of claim 20 wherein the precursor is ionically neutral and consists of X z-y M(NR) y , where X is halogen, M is metal, z is the valence of M, R is alkyl, aryl, or silyl, and y is at least 1.
29. The method of claim 28 wherein z is 4, 5, or 6 and y is 1 to 5.
30. The method of claim 20 wherein the amino and imino ligands comprise, respectively, dialkylamino and alkylimino ligands.
31. The method of claim 20 wherein the metal or semimetal is selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten.
32. The method of claim 20 wherein the precursor is selected from the group consisting of trichloro(dimethylamino)hafnium, trichloro(dimethylamino)titanium (IV), trichloro(dimethylamino)zirconium (IV), trichloro(diethylamino)hafnium, trichloro(diethylamino)titanium (IV), and trichloro(diethylamino)zirconium (IV).
33. The method of claim 20 wherein the deposition method is ALD and depositing the layer comprises chemisorbing a precursor monolayer on the substrate using the precursor, reacting a second precursor with the precursor monolayer, modifying the precursor monolayer, and yielding the layer as a product monolayer.
34. The method of claim 20 wherein the deposition method is CVD, exposing the substrate to the precursor comprises simultaneously exposing the substrate to a second precursor, and depositing the layer comprises continuously reacting the precursor with the second precursor throughout the deposition, a product of the reaction including the metal, the semimetal, or the oxide, nitride, silicide, sulfide, or selenide of the metal or semimetal, and forming the layer from the reaction product.
35. The method of claim 20 wherein the substrate comprises a bulk semiconductor wafer.
36. A deposition method comprising:
providing a deposition substrate;
exposing the substrate to a precursor consisting of at least one imino ligand, a metal or a semimetal, and at least one halide ligand; and
depositing over the substrate a layer including the metal, the semimetal, or an oxide, nitride, silicide, sulfide, or selenide of the metal or semimetal.
37. The method of claim 36 wherein the layer exhibits less halogen content than otherwise exhibited with a halide ligand taking the place of each imino ligand.
38. The method of claim 36 wherein the precursor exhibits a vapor pressure of greater than 0.1 Torr at less than or equal to 120° C.
39. The method of claim 36 wherein the deposition method is ALD and depositing the layer comprises chemisorbing a precursor monolayer on the substrate using the precursor, reacting a second precursor with the precursor monolayer, modifying the precursor monolayer, and yielding the layer as a product monolayer.
40. The method of claim 36 wherein the precursor is ionically neutral and consists of X z-y M(NR) y , where X is halogen, M is metal, z is the valence of M, R is alkyl, aryl, or silyl, and y is at least 1.
41. The method of claim 40 wherein z is 4, 5, or 6 and y is 1 to 5.
42. The method of claim 36 wherein the imino ligand comprises an alkylimino ligand.
43. The method of claim 36 wherein the metal or semimetal is selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten.
44. The method of claim 36 wherein the deposition method is CVD, exposing the substrate to the precursor comprises simultaneously exposing the substrate to a second precursor, and depositing the layer comprises continuously reacting the precursor with the second precursor throughout the deposition, a product of the reaction including the metal, the semimetal, or the oxide, nitride, silicide, sulfide, or selenide of the metal or semimetal, and forming the layer from the reaction product.
45. The method of claim 36 wherein the substrate comprises a bulk semiconductor wafer.