High coordination sphere group 2 metal β-diketiminate precursors

The present patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/086,341 filed Aug. 5, 2008.

The semiconductor fabrication industry continues to explore metal containing precursors for chemical vapor deposition processes including atomic layer deposition for fabricating conformal metal containing films on substrates such as silicon, metal nitride, metal oxide and other metal-containing layers using these metal-containing precursors. Barium and strontium containing precursors are especially sought after for the deposition of thin barium and strontium oxide containing films for advanced memory device manufacture. The prior art has attempted to provide precursors for these applications, as set forth below. However, none of the metal complexes in the prior art share the special characteristic of the complexes disclosed in this invention.

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McGeachin, Canadian Journal of Chemistry, p. 1903, Vol. 46, 1968.

Park, K. H. and Marshall, W. J. (2005), J. Org. Chem. 70, (6), 2075-2081.

The present invention is directed to high coordination sphere Group 2 metal diiminate compositions, for example bis(N-(2,2-bis(methoxy)ethyl)-4-(2,2-bis(methoxy)ethylimino)-2-penten-2-aminato) barium; and the deposition of group 2 metal containing films from such metal complex compositions by chemical vapor deposition, pulsed chemical vapor deposition, molecular layer deposition or atomic layer deposition. Exemplary films include but are not limited to barium, strontium titanate ternary films or strontium titanate binary films for electronic materials device manufacturing.

FIG. 1 is the molecular structure of bis(N-(2,2-bis(methoxy)ethyl)-4-(2,2-bis(methoxy)ethylimino)-2-penten-2-aminato) barium as characterized by X-ray single crystal analysis.

In contrast to the prior art precursors described above, the compounds of the present invention have aliphatic side chains attached to the nitrogen atoms of a β-diketimine ligand functionalized groups with oxygen and nitrogen atoms. These groups, being anchored to the main body of the β-diketimine ligand can then coordinate to the metal center to provide a large coordination sphere around the metal center. Consequently, this stabilizes the complex and permits monomeric metal complexes to form, especially in the case of barium, which has a tendency to form dimeric, trimeric, tetrameric or polymeric complexes of lesser utility as precursors due to their high molecular weight and extremely low vapor pressure. In the prior arts mentioned above, when β-diketimine ligands are used for Group 2 metal presursors, the groups attached to the β-diketimine nitrogen atoms are simple alkyl groups or alkyl substituted aromatics with no coordinating nitrogen or oxygen atoms.

For instance, in the case where the ligand anion [MeC(NCMe 3 )CHC(HNCMe 3 )Me]— coordinates to barium, there are no coordinating oxygen atoms and no additional nitrogen atoms beyond the nitrogen atoms of the β-diketimine ligand.

By contrast, the precursors of the present invention are based upon diketimine ligands that provide an array of coordinating oxygen and nitrogen groups, which can wrap around and encapsulate the metal center.

This invention is directed to metal containing polydentate 6-diketiminates and their solutions for vapor delivery by direct liquid injection, wherein the polydentate β-diketiminates incorporate nitrogen or oxygen functionality by attaching them to the imino groups, as metal coordinating side chains. It also includes a novel method of synthesizing diketiminate ligands in high yield and high purity which avoids the use of toxic alkylating agents, such as triethyloxonium tetrafluoroborate (McGeachin, Canadian Journal of Chemistry, p. 1903, Vol. 46, 1968) or other corrosive and toxic reagents, such as PCI 5 or dimethylsulfate, (Park, J. Org. Chem., 2005, 70, 2075-2081) and, importantly, permits the facile synthesis of diketiminate ligands, which bear coordinating atoms in addition to the nitrogen atoms of the diketiminate unit.

Thus, the synthetic problems and complications arising from unwanted O and N alkylation occurring on the coordinating side chains by using the above mentioned published procedures to make the new molecules of this disclosure are eliminated. In this way, previously unreported diketiminate ligands are made for the first time using the novel synthesis of the present invention. The new β-diketimines include: MeC(NCH 2 CH(OMe) 2 )CHC(NHCH 2 CH(OMe) 2 )Me; MeC(NCH 2 CH 2 N(CH 3 ) 2 )CHC(NH CH 2 CH 2 N(CH 3 ) 2 )Me; and MeC(NCH 2 CH 2 OMe)CHC(NHCH 2 CH 2 OMe)Me.

The new metal complexes of this disclosure are characterized by β-diketimine and ketoimine ligands, which contain additional coordinating atoms beyond the two nitrogen atoms of the diimine ligand, so as to provide a coordination sphere for the metal center. In this way, the entire coordination sphere is an integral part of the structure of the resulting metal complex. The polydentate metal β-diketiminates are selected from the group represented by the structures:

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium and radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 are individually selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy, and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, acyl, halogen and aryl having from 6 to 10 carbon atoms; R 4,6 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 6 to 10 carbon atoms, preferably R 4,6 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center; R 5,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms, and they can be connected to form a ring containing carbon, oxygen, or nitrogen atoms. In addition, groups R 5 or R 4 can be connected to R 6 and R 7 of the same diketimine ligand or to R 4 , R 5 , R 6 and R 7 of the other diketimine ligand. Similarly, R 6 and R 7 can be connected to the same groups in the other ligand. In addition, cyclic groups can also be formed by connecting R 1 to R 2 , R 6 or R 7 ; R 3 to R 2 , R 4 or R 5 ; R 1 to R 2 , R 3 to R 2 .

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy, and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy, having from 1 to 10 carbon atoms, nitro, acyl and aryl having from 6 to 10 carbon atoms. R 1 , R 2 and R 3 can also be connected to form ring structures. R 4,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 6 to 10 carbon atoms, preferably R 4,7 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center; R 5,6,8,9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms, and they can be connected to form a ring containing carbon, oxygen, or nitrogen atoms. In addition, groups R 4 , R 5 and R 6 can be connected to R 7 , R 8 and R 9 of the same diketimine ligand or to R 4 , R 5 , R 6 , R 7 , R 8 or R 9 of the other diketimine ligand. Similarly, R 7 , R 8 and R 9 can be connected to the same groups in the other ligand. In addition R 1 can be connected to R 2 , R 7 , R 8 or R 9 and R 3 can be connected to R 4 , R 5 and R 6 .

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, and fluoroalkyl having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, acyl, halogen and aryl having from 6 to 10 carbon atoms. R 1 , R 2 and R 3 can also be connected to form rings. R 4,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 6 to 10 carbon atoms. Preferably R 4,7 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center; R 5,6,8,9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms, and they can be connected to form a ring containing carbon, oxygen, or nitrogen atoms. Groups R 4 , R 5 or R 6 can be connected to R 7 , R 8 or R 9 of the same diketimine ligand or to R 4 , R 5 , R 6 , R 7 , R 8 or R 9 of the other diketimine ligand. Similarly, R 7 , R 8 or R 9 can be connected to the same groups in the other ligand. In addition, R 1 can also be attached to R 2 , R 7 , R 8 and R 9 ; R 3 can be attached to R 2 , R 4 , R 5 or R 6 .

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of alkyl, fluoroalkyl, alkoxy, and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, acyl, halogen and aryl having from 6 to 10 carbon atoms. R 1 , R 2 , and R 3 can be connected to form rings. R 4,8 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 6 to 10 carbon atoms. Preferably, R 4,8 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center; R 5-7,9-11 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms, and they can be connected to form a ring containing carbon, oxygen, or nitrogen atoms. In addition, groups R 4 , R 5 , R 6 or R 7 can be connected to R 8 , R 9 , R 10 or R 11 of the same diketimine ligand or to R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 or R 11 of the other diketimine ligand. Similarly, R 8 , R 9 , R 10 or R 11 can be connected to the same groups in the other ligand. R 1 can also be attached to R 8 , R 9 , R 10 or R 11 and R 3 can be attached to R 4 , R 5 , R 6 or R 7 .

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, acyl, halogen and aryl having from 6 to 10 carbon atoms. R 1 , R 2 and R 3 can be connected to form rings R 4,5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms, preferably R 4,5 contains 1 or 2 carbon atoms, thus making a five- or six-member coordinating ring to the metal center; n=3, 4, 5. In addition, R 4 can be connected to R 5 of the same ligand or to R 4 or R 5 of the other ligand. Similarly, R 5 can be connected to the same group of the other ligand. R 1 can also be attached to R 2 or R 5 and R 3 can be attached to R 2 or R 4 .

For the structures A through E above it is also possible for the β-diketimine ligands to be asymmetric such that the groups attached to one of the diketimine nitrogens, as described above in A-E is different for the corresponding group, also described above in A-E, attached to the other diketimine nitrogen. Two such asymmetric ligands can be complexed to a metal center to form a metal complex or, alternately, two different asymmetric ligands can be complexed to a metal center to form a metal complex. Alternatively, two different symmetric ligands can be complexed to a metal center to form a metal complex.

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium, or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy, and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro acyl, halogen and aryl having from 6 to 10 carbon atoms. R 1 , R 2 and R 3 can be connected to form rings. R 4 ′5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms, preferably R 4,5 contains 2 or carbon atoms, thus making a five- or six-member coordinating ring to the metal center; Alternatively, R 4 can also contain ether or amine groups which can also coordinate to the metal center. R 6 is selected from the group consisting of alkyl, fluoroalkyl, cycloaliphatic, aryl. In addition R 1 can be attached to R 4 , R 2 , R 3 , R 4 , R 5 or R 6 ; R 6 can be attached to R 1 , R 2 , R 4 , R 5 or R 6 .

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy, and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, acyl, halogen and aryl having from 6 to 10 carbon atoms; R 4,5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms, preferably R 4,5 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center; Alternatively, R 4 can also contain ether or amine groups which can also coordinate to the metal center. R 6,7 are selected from the group consisting of alkyl, fluoroalkyl, cycloaliphatic, and aryl. In addition, R 1 can be attached to R 2 , R 3 , R 4 , R 5 , R 7 and R 1 , R 2 and R 3 can be connected into ring structures

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, acyl, halogen and aryl having R 2 and R 3 can be connected R 4,5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms, preferably R 4 ′5 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center. Alternatively, R 4 can also contain ether or amine groups which can also coordinate to the metal center. R 6,7 are selected from the group consisting of alkyl, fluoroalkyl, cycloaliphatic, aryl. R 3 can be connected to R 1 , R 2 , R 4 , R 5 , R 6 , R 7 .

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, preferably strontium and barium. A variety of organo groups may be employed as for example wherein R 1,3 is selected from the group consisting of hydrogen, alkyl, fluoroalkyl, alkoxy, and fluoroalkoxy having from 1 to 10 carbon atoms, preferably a group containing 1 to 6 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy, nitro, acyl, halogen and aryl having from 1 to 10 carbon atoms; R 4,5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms, preferably R 4,5 contains 2 or 3 carbon atoms, thus making a five- or six-member coordinating ring to the metal center. Alternatively, R 4 can also contain ether or amine groups which can also coordinate to the metal center. R 6 -9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms.

In addition to the above complexes, while not wishing to be bound by theory, mixed Group 2 metal, preferably barium, complexes can also be made where two different diketimine anions are coordinated to one metal center or where one diketiminate anion and one other organic or inorganic anion coordinate to the Group 2 metal to make a complete complex. Examples of such alternative anions include, but are not limited to, pyrrolyls, imidazolates, beta-diketonates, acetates, ketoiminates, C 1-10 alkoxides, amides, hydrides, beta-ketoesters, amidinates, guanidinates, cyclopentadienyl, alkyl substituted cyclopentadienyl, cyanide, isocyanide, formate, oxalate, malonate, phenoxide, thiolate, sulfide, nitrate, C 1-10 alkyl, silylalkyl, fluoroalkyl, and C 4-12 aryl.

Mixed ligands of diketimine and other ligands are also contemplated such as a metal complex composition having a structure comprising;

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium, and mixtures thereof; R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl, having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, or halogen and aryl having from 4 to 10 carbon atoms; R 4,6 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 4 to 10 carbon atoms; R 5,7 are selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; the second mono anion L is selected from the group consisting of pyrrolyls, imidazolates, beta-diketonates, acetates, ketoiminates, alkoxides, amides, hydrides, beta-ketoesters, amidinates, guanidinates, cyclopentadienyl, alkyl substituted cyclopentadienyl, cyanide, isocyanide, formate, oxalate, malonate, phenoxide, thiolate, sulfide, nitrate, alkyl, silylalkyl, fluoroalkyl, and aryl; or

wherein M is a Group 2 metals selected from the group consisting of magnesium, calcium, strontium, barium or radium; R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 6 to 10 carbon atoms; R 5,6,8,9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; the second mono anion L is selected from the group consisting of pyrrolyls, imidazolates, beta-diketonates, acetates, ketoiminates, alkoxides, amides, hydrides, beta-ketoesters, amidinates, guanidinates, cyclopentadienyl, alkyl substituted cyclopentadienyl, cyanide, isocyanide, formate, oxalate, malonate, phenoxide, thiolate, sulfide, nitrate, alkyl, silylalkyl, fluoroalkyl, and aryl; or,

wherein M is a Group 2 metals selected from the group consisting of magnesium, calcium, strontium, barium or radium; R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 4 to 10 carbon atoms; R 5,6,8,9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; the second mono anion L is selected from the group consisting of pyrrolyls, imidazolates, beta-diketonates, acetates, ketoiminates, alkoxides, amides, hydrides, beta-ketoesters, amidinates, guanidinates, cyclopentadienyl, alkyl substituted cyclopentadienyl, cyanide, isocyanide, formate, oxalate, malonate, phenoxide, thiolate, sulfide, nitrate, alkyl, silylalkyl, fluoroalkyl, and aryl; or,

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium; R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,8 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms and aryl having from 4 to 10 carbon atoms; R 5-7,9-11 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; the second mono anion L is selected from the group consisting of pyrrolyls, imidazolates, beta-diketonates, acetates, ketoiminates, alkoxides, amides, hydrides, beta-ketoesters, amidinates, guanidinates, cyclopentadienyl, alkyl substituted cyclopentadienyl, cyanide, isocyanide, formate, oxalate, malonate, phenoxide, thiolate, sulfide, nitrate, alkyl, silylalkyl, fluoroalkyl, and aryl; and,

wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium or radium; R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms; n=3, 4, 5; the second mono anion L is selected from the group consisting of pyrrolyls, imidazolates, beta-diketonates, acetates, ketoiminates, alkoxides, amides, hydrides, beta-ketoesters, amidinates, guanidinates, cyclopentadienyl, alkyl substituted cyclopentadienyl, cyanide, isocyanide, formate, oxalate, malonate, phenoxide, thiolate, sulfide, nitrate, alkyl, silylalkyl, fluoroalkyl, and aryl.

The compositions of the Present Invention may also be mixed β-diketiminate ligands complexed with a metal, M, wherein M is a Group 2 metal selected from the group consisting of magnesium, calcium, strontium, barium and radium; bonded through the open bonds shown to the left of any two different ligands selected from the group consisting of;

wherein R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl, having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,6 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 4 to 10 carbon atoms; R 5,7 are selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; silylalkyl, fluoroalkyl, and aryl;

wherein R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 6 to 10 carbon atoms; R 5,6,8,9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms;

wherein R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,7 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, and aryl having from 4 to 10 carbon atoms; R 5,6,8,9 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms;

wherein R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,8 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms and aryl having from 4 to 10 carbon atoms; R 5-7,9-11 are individually selected from the group consisting of alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl having from 4 to 10 carbon atoms; and,

wherein R 1,3 are individually selected from the group consisting of hydrogen, alkyl and fluoroalkyl having from 1 to 10 carbon atoms, cycloaliphatic and aryl, having from 4 to 10 carbon atoms; R 2 is selected from the group consisting of hydrogen, alkyl and alkoxy having from 1 to 10 carbon atoms, nitro, halogen and aryl having from 4 to 10 carbon atoms; R 4,5 are individually selected from the group consisting of alkyl having from 1 to 10 carbon atoms; n=3, 4, 5

These Group 2 metal complexes, based upon polydentate β-diketiminate ligands, can be utilized as potential precursors to prepare metal oxide films via either the chemical vapor deposition (CVD), molecular layer deposition (MLD), or atomic layer deposition (ALD) method at temperatures less than 600° C. with oxidizing agents such as water, ozone, oxygen, oxygen plasma, nitrous oxide or combinations thereof. For multi-component metal oxide, these complexes can be premixed as source materials. These metal-containing complexes with polydentate β-diketiminate ligands can be delivered in vapor phase into a CVD or ALD reactor via well-known bubbling or vapor draw techniques. A direct liquid injection can also be employed by dissolving the complexes in a suitable solvent or a solvent mixture to prepare a solution with a molar concentration from 0.001 to 2 M depending the solvent or mixed-solvents employed.

The solvent employed to solubilize the precursor for use in a deposition process may comprise any compatible solvent or mixtures of solvent including aliphatic hydrocarbons, aromatic hydrocarbons, ethers, amines, esters, nitrites, amides and alcohols. The solvent component of the solution preferably comprises a solvent selected from the group consisting of glyme solvents having from 1 to 20 ethoxy —(C 2 H 4 O)— repeat units; C 2 -C 12 alkanols, organic ethers selected from the group consisting of dialkyl ethers comprising C 1 -C 6 alkyl moieties, C 4 -C 8 cyclic ethers; C 12 -C 60 crown ethers, C 2 -C 20 amides; C 6 -C 12 aliphatic hydrocarbons; C 6 -C 18 aromatic hydrocarbons; organic esters; organic amines, polyamines, organic amides and linear or cyclic amine-ether solvents such as Me 2 NCH 2 CH 2 OCH 2 CH 2 NMe 2 .

Another class of solvents that offers advantages is the organic amide class of the form RCONR′R″ wherein R and R′ are alkyl having from 1-10 carbon atoms and they can be connected to form a cyclic group (CH 2 ) n , wherein n is from 4-6, preferably 5, and R″ is selected from alkyl having from 1 to 4 carbon atoms and cycloalkyl. N-methyl and N-cyclohexyl-2-pyrrolidinones, N,N-Diethylacetamide, and N,N-Diethylformamide are examples.

Several advantages can be achieved through these metal-containing polydentate β-diketiminates as precursors for chemical vapor deposition or atomic layer deposition, and these include:

an ability to form reactive complexes in good yield; an ability to form monomeric complexes, particularly strontium and barium complexes by complexing with diketiminatof ligands, thus achieving higher vapor pressure than that of the known strontium and barium precursors. The known strontium and barium precursors are typically polymeric complexes with extremely low vapor pressure. an ability to form highly conformal metal oxide thin films when used as volatile precursors for CVD and ALD deposition for use in microelectronic devices; an ability to enhance the surface reaction between the metal-containing polydentate β-diketiminates and the surface of a substrate due to the high chemical reactivity of the complexes; an ability to tune the physical and chemical properties of these metal-containing polydentate β-diketiminates via a change in the R 1-9 groups; additionally, metal complexes can also be made by coordinating two different carefully chosen diketimnate anions to a metal center, such as barium, such that the two ligands experience an optimal ‘fit’ or ‘interlock’ with each other and around the metal in such a way as to provide an adequate coordination sphere to create a stable monomeric complex; and, a novel and practical process for the synthesis of new diketiminate ligands avoiding the use of toxic alkylating agents.

The present invention is also a process for synthesizing diketimine ligands without the use of toxic alkylating agents comprising the following steps:

(1) reacting a primary amine with a beta-diketone to yield a ketoimine ligand;

(2) lithiating the same or different primary amine;

(3) trialkysilylating the lithiated primary amine to give a trialkylsily amine;

(4) repeating the lithiation/trialkylsilylaltion steps to yield a bis(trialkylsily)amine;

(5) the ketoimine ligand of step (1) is mixed with the bis(trialkylsilyl)amine of step (2) and a strong acid;

(6) the reaction mixture is then treated with a solution of a base; and

(7) the diketimine ligand is then isolated from the reaction mixture by vacuum distillation.