Group 2 metal precursors for depositing multi-component metal oxide films
Novel Sr and Ba complexes containing both beta-diketonates and N-methyl-pyrrolidone were synthesized and characterized. TGA experiments indicated these complexes are volatile, they can be employed as precursors for ALD strontium titanate (STO) or barium strontium titanate films (BST) films in semiconductor fabrication.
1. A metal containing complex represented by the structure:
wherein M is selected from Ca, Sr, Ba, and mixtures thereof; R 1 and R 3 are independently selected from the group consisting of C 1 -C 10 linear or branched alkyl, C 1 -C 10 alkoxyalkyl, C 1 -C 10 fluoroalkyl, C 4 -C 12 cycloaliphatic, and C 4 -C 12 aryl; R 2 is selected from the group consisting of hydrogen, C 1 -C 10 linear or branched alkyl, C 1 -C 10 fluoroalkyl, C 1 -C 10 alkoxy, C 4 -C 12 cycloaliphatic, and C 6 -C 12 aryl; L 1 is an organic amide having a formula RCONR′R″ wherein R and R′ are independently linear or branched alkyl having from 1-10 carbon atoms wherein R and R′ can be connected to form a cyclic group having from 4 to 6 atoms, and R″ is selected from the group consisting of C 1 -C 4 alkyl and C 4 -C 8 cycloalkyl; L 2 is selected from the group consisting of H 2 O and ROH wherein R is a C 1 -C 10 linear or branched alkyl group or a cyclic group having from 4 to 6 atoms, and an organic amide having a formula RCONR′R″ wherein R and R′ are linear or branched alkyl having from 1-10 carbon atoms wherein R and R′ can be connected to form a cyclic group having from 4 to 6 atoms, and R″ is selected from the group consisting of a C 1 -C 4 alkyl and a C 3 -C 8 cycloalkyl; n is a number selected from between 1 and 4; m is selected from a number between 0 to 4, and p is selected from 1 and 2.
2. The metal containing complex of claim 1 wherein L 1 and L 2 are selected from the group consisting of N-methylpyrrolidinone (NMP), N,N-Diethylacetamide (DEAC), N,N-Dimethylacetamide (DMAC), N-cyclohexyl 2-pyrrolidinone, H 2 O, and ROH.
3. The metal containing complex of claim 1 wherein R 1 and R 3 are selected from the group consisting of t-butyl and t-pentyl; and R 2 is selected from the group consisting of hydrogen, methyl and ethyl.
4. The metal containing complex of claim 1 wherein M is strontium; R 1 and R 3 are each t-butyl, R 2 is hydrogen, L 1 and L 2 are each N-methyl-pyrrolidone, n=1.5, m=0.5, and p=2.
5. The metal containing complex of claim 1 wherein M is strontium; R 1 and R 3 are each t-butyl; R 2 is hydrogen; L 1 is N,N-Diethylacetamide (DEAC); n=1.5; m=0; and p=2.
6. The metal containing complex of claim 1 wherein M is barium; R 1 and R 3 are each CF 3 ; R 2 is hydrogen; L 1 and L 2 are each N-methyl-pyrrolidone; n=1.5; m=2; and p=2.
7. The metal containing complex of claim 1 wherein M is barium; R 1 and R 3 are each t-butyl; R 2 is hydrogen; L 1 is N N-methyl-pyrrolidone; n=2; L 2 =H 2 O; m=1; and p=2.
8. The metal containing complex of claim 1 dissolved in 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; C 6 -C 12 aliphatic hydrocarbons; C 6 -C 18 aromatic hydrocarbons; organic esters; organic amines; and polyamines and organic amides.
9. The metal containing complex of claim 8 wherein the solvent is an organic ether 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 O 4 —O 20 ethers (wherein C is the number of carbon atoms in the crown ether compound and O is the number of oxygen atoms in the crown ether.
10. The metal containing complex of claim 8 wherein the solvent is an organic amide selected from the group consisting of N-methylpyrrolidinone (“NMP”), N,N-Diethylacetamide (DEAC), N,N-Dimethylacetamide (DMAC), and N-cyclohexyl 2-pyrrolidinone.
11. A vapor deposition process for forming a conformal multi-component metal oxide thin film on a substrate wherein at least two metal containing complexes and an oxygen containing agent are introduced to a deposition chamber and a multi-component metal oxide film is deposited on a substrate, the improvement which comprises using at least two metal containing complexes, having different metals, selected from:
wherein M is selected from Ca, Sr, and Ba; R 1 and R 3 are independently selected from the group consisting of C 1 -C 10 linear or branched alkyl, C 1 -C 10 alkoxyalkyl, C 1 -C 10 fluoroalkyl, C 4 -C 12 cycloaliphatic, and C 4 -C 12 aryl; R 2 is selected from the group consisting of hydrogen, C 1 -C 10 linear or branched alkyl, C 1 -C 10 fluoroalkyl, C 1 -C 10 alkoxy, C 4 -C 12 cycloaliphatic, and C 6 -C 12 aryl; L 1 is an organic amide having a formula RCONR′R″ wherein R and R′ are independently linear or branched alkyl having from 1-10 carbon atoms wherein R and R′ can be connected to form a cyclic group having from 4 to 6 atoms, and R″ is selected from the group consisting of C 1 -C 4 alkyl and C 4 -C 8 cycloalkyl; L 2 is selected from the group consisting of H 2 O and ROH wherein R is a C 1 -C 10 linear or branched alkyl group or a cyclic group having from 4 to 6 atoms, and an organic amide having a formula RCONR′R″ wherein R and R′ are independnently linear or branched alkyl having from 1-10 carbon atoms wherein R and R′ can be connected to form a cyclic group having from 4 to 6 atoms, and R″ is selected from the group consisting of a C 1 -C 4 alkyl and a C 4 -C 8 cycloalkyl; n is a number selected from between 1 and 4; m is selected from a number between 0 to 4, and p is selected from 1 and 2.
12. The process of claim 11 wherein the vapor deposition process is selected from the group consisting of chemical vapor deposition, cyclic chemical vapor deposition and atomic layer deposition.
13. The process of claim 11 wherein the oxygen containing agent is selected from the group consisting of N 2 O, O 2 , H 2 O 2 , H 2 O, ozone, O 2 plasma, H 2 O plasma, organic peroxide, and mixtures thereof.
14. The process of claim 11 wherein a first metal containing complex is selected from the group consisting of Sr 2 (tmhd) 4 (NMP) 4 , and Sr 2 (tmhd) 4 (DEAC) 3 , and a second metal containing complex is selected from the group consisting of Ba 2 (tmhd) 4 (NMP) 4 .(H 2 O) 2 , Ba 2 (hfac) 4 (NMP) 5 .
15. The process of claim 14 wherein a third metal containing complex is selected from the group consisting of titanium containing alkoxides and beta-ketonates and mixtures thereof.
16. The process of claim 15 wherein the third metal containing complex is selected from the group consisting of Ti(OPr i ) 4 , Ti(tmhd) 2 (OPr i ) 2 , where Pr i =isopropyl, where tmhd=2,2,6,6-tetramethyl-3,5-heptanedionate, Ti(mpd)(tmhd) 2 , where mpd=2-methyl-2,4-pentanedioxy, Ti(4-(2-methylethoxy)imino-2-pentanoate) 2 and mixtures thereof.