Organometallic compounds useful for chemical phase deposition

Abstract

A method for forming a metal-containing film includes: a) providing at least one substrate; b) delivering to said substrate at least one compound of Formula 1 in the gaseous phase, (R.sup.1R.sup.2R.sup.3 (Si))—Co(CO).sub.4 (Formula 1), wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected lower alkyl groups; and c) simultaneously with or subsequently to step b), delivering to said substrate a co-reagent in the gaseous phase, the co-reagent being lower alcohol. Further, a method of selectively depositing a metal-containing film includes: a) providing at least two substrates comprising different materials, one of said at least two substrates has an affinity for Si and another of said at least two substrates has an affinity for CO; b) delivering to said substrates at least one compound of the Formula 1 in the gaseous phase; and c) simultaneously with or subsequently to step b), delivering to said at least two substrates at least one co-reagent in the gaseous phase.

Claims

1. A method for forming a film by a vapor deposition process, the method comprising: a) providing at least one substrate, b) delivering to said substrate at least one compound of Formula 1 in the gaseous phase,
(R.sup.1R.sup.2R.sup.3 (Si))—Co(CO).sub.4  Formula 1 wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected lower alkyl groups, c) simultaneously with or subsequently to step b), delivering to said substrate a co-reagent in the gaseous phase, the co-reagent being lower alcohol, and d) removing gaseous reaction products, wherein the film is a metal film.

2. The method of claim 1, wherein the compound is selected from the group consisting of EtMe.sub.2SiCo(CO).sub.4, and .sup.tBuMe.sub.2SiCo(CO).sub.4.

3. The method of claim 2, wherein the compound of Formula 1 is .sup.tBuMe.sub.2SiCo(CO).sub.4.

4. The method of claim 1, wherein the co-reagent is methanol.

5. The method of claim 1, wherein the vapor deposition process is chemical vapor deposition.

6. The method of claim 1, wherein the vapor deposition process is atomic layer deposition.

7. A method of selectively depositing a metal-containing film on one or more of a plurality of substrates, the method comprising: a) providing at least two substrates comprising different materials, one of said at least two substrates has an affinity for Si and another of said at least two substrates has an affinity for CO, b) delivering to said substrates at least one compound of Formula 1 in the gaseous phase
(R.sup.1R.sup.2R.sup.3 (Si))—Co(CO).sub.4  Formula 1 wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected lower alkyl groups having from 1 to 4 carbon atoms, c) simultaneously with or subsequently to step b), delivering to said at least two substrates at least one co-reagent in the gaseous phase, the at least one co-reagent being selected from ammonia, methanol, oxygen, and a mixture of ammonia and H.sub.2, wherein the mixture of ammonia and H.sub.2 includes at least 25% H.sub.2 as a percentage of the total mixture of ammonia and H.sub.2, and d) removing gaseous reaction products.

8. The method of claim 7, wherein the one of said at least two substrates is SiO.sub.2.

9. The method of claim 8, wherein the compound of Formula 1 is .sup.tBuMe.sub.2SiCo(CO).sub.4.

10. The method of claim 7, wherein the one of said at least two substrates is SiN.

11. The method of claim 10, wherein the compound of Formula 1 is .sup.tBuMe.sub.2SiCo(CO).sub.4.

12. A method of selectively depositing a metal-containing film on one or more of a plurality of substrates, the method comprising: a) providing at least two substrates comprising different materials, one of said at least two substrates has an affinity for Si and another of said at least two substrates has an affinity for CO, b) delivering to said substrates at least one compound of Formula 1 in the gaseous phase
(R.sup.1R.sup.2R.sup.3 (Si))—Co(CO).sub.4  Formula 1 wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected lower alkyl groups having from 1 to 4 carbon atoms, c) simultaneously with or subsequently to step b), delivering to said at least two substrates at least one co-reagent in the gaseous phase, the at least one co-reagent being selected from ammonia, methanol, oxygen, and a mixture of ammonia and H.sub.2, wherein the mixture of ammonia and H.sub.2 includes at least 25% H.sub.2 as a percentage of the total mixture of ammonia and H.sub.2, and d) removing gaseous reaction products, wherein the another of said at least two substrates having an affinity for CO is selected from the group consisting of Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, and Os.

13. The method of claim 12, wherein the metal containing film is Co.

14. The method of claim 13, wherein the compound of Formula 1 is .sup.tBuMe.sub.2SiCo(CO).sub.4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the vapour pressures of compounds of the invention compared to a compound of the art.

(2) FIG. 2 shows the thermal stability of .sup.tBuMe.sub.2SiCo(CO).sub.4.

(3) FIG. 3 shows the thermal stability of a compound of the art CCTBA (3,3-Dimethyl-1-butyne)dicobalthexacarbonyl).

(4) FIG. 4 shows a schematic of a CVD system used for exemplary thin film deposition.

(5) FIG. 5 shows the binding energies of .sup.tBuMe.sub.2SiCo(CO).sub.4 on different surfaces.

(6) FIG. 6 shows the TGA of EtMe.sub.2SiC(CO).sub.4.

(7) FIG. 7 shows the vapor pressure of EtMe.sub.2SiCo(CO).sub.4.

(8) FIG. 8 shows the NMR spectrum of Et.sub.3SiC(CO).sub.4.

(9) FIG. 9 shows the NMR spectrum of .sup.tBuMe.sub.2SiCo(CO).sub.4.

(10) FIG. 10 shows the TGA of .sup.tBuMe.sub.2SiCo(CO).sub.4.

(11) FIG. 11 shows the vapour pressure of .sup.tBuMe.sub.2SiCo(CO).sub.4.

(12) FIG. 12 shows the thermal growth rate as a function of temperature for deposition using .sup.tBuMe.sub.2SiCo(CO).sub.4.

(13) FIG. 13 shows the NMR of PhMe.sub.2SiCo(CO).sub.4.

(14) FIG. 14 shows the resistivity of a cobalt film deposited using .sup.tBuMe.sub.2SiC(CO).sub.4.

(15) FIG. 15 shows the growth rate as a function of pressure and the hydrogen to ammonia ratio for deposition using tBuMe.sub.2SiCo(CO).sub.4.

(16) FIG. 16 shows a demonstration of the process of selective deposition using a compound of the invention.

DETAILED DESCRIPTION

(17) An organometallic compound is provided. The compound corresponds in structure to Formula 1:
[(R.sup.1R.sup.2R.sup.3(A)).sub.x—M(CO).sub.y].sub.z

(18) wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of H, a lower alkyl group and a phenyl group optionally substituted with at least one independently selected lower alkyl group, with the proviso that at least one of R.sup.1, R.sup.2 and R.sup.3 must be other than H;

(19) M is selected from the group consisting of the cobalt group metals, the iron group metals, the manganese group metals, and the chromium group metals;

(20) A is selected from the group consisting of Si, Ge, and Sn; and wherein:

(21) x=1, y=4, and z=1 when M is selected from the group consisting of a cobalt group metal,

(22) x=1, y=5, and z=1 when M is selected from the group consisting of a manganese group metal,

(23) x=2, y=4, and z=1 when M is selected from the group consisting of a chromium group metal, and

(24) x=2, y=4, and z=1 or, alternatively, x=1, y=4, and z=2 when M is selected from the group consisting of an iron group metal.

(25) In various embodiments of the invention, metal carbonyl compounds with trialkyl silyl, germanyl or stannyl ligands, methods of making such compounds and methods of using such compounds, in the presence of appropriate co-reagents, to form substantially-pure metal-containing films, such as, but not limited to, metal, metal phosphide, metal sulphide, metal oxide, metal boride and metal nitride films, are provided.

(26) The use of more than one compound of Formula 1, each having a different value of M, in the deposition processes disclosed herein results in the formation of films of substantially-pure metal alloys, mixed-metal oxides, mixed-metal nitrides, mixed-metal phosphides, mixed-metal borides or mixed-metal sulphides, the nature of the film formed being dependent upon the nature of the co-reagent used, as described herein.

(27) In a first embodiment of the invention the compound corresponds to Formula 1 wherein M is a cobalt group metal and A is Si. Exemplary compounds include EtMe.sub.2SiCo(CO).sub.4, Et.sub.3SiCo(CO).sub.4, Me.sub.2SiCo(CO).sub.4 and PhMe.sub.2SiCo(CO).sub.4.

(28) In a second embodiment of the invention the compound corresponds to Formula 1 wherein M is an iron group metal, A is Si, x=2, y=4, and z=1. Exemplary compounds include (Et.sub.3Si).sub.2Fe(CO).sub.4.

(29) In a third embodiment of the invention the compound corresponds to Formula 1 wherein M is an iron group metal, A is Si, x=1, y=4, and z=2.

(30) In a fourth embodiment of the invention the compound corresponds to Formula 1 wherein M is a manganese group metal and A is Si. Exemplary compounds include Et.sub.3SiMn(CO).sub.5.

(31) In a fifth embodiment of the invention the compound corresponds to Formula 1 wherein M is a chromium group metals and A is Si. Exemplary compounds include (PhMe.sub.2Si).sub.2W(CO).sub.4.

(32) Embodiments of the invention include those in which R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of a lower alkyl group and a phenyl group optionally substituted with at least one independently selected lower alkyl group.

(33) Exemplary compounds include those in which R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of a lower alkyl group having from 1 to 5 carbon atoms. Other exemplary compounds include those in which at least one of R.sup.1, R.sup.2 and R.sup.3 is a methyl group.

(34) Other exemplary compounds include those in which R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of a lower alkyl group having from 1 to 4 carbon atoms. Other exemplary compounds include those in which at least one of R.sup.1, R.sup.2 and R.sup.3 is a methyl group

(35) Other exemplary compounds include those in which R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of a lower alkyl group having from 1 to 4 carbon atoms, two of which are methyl group, the third of which is a lower alkyl group having from 3 to 4 carbon atoms.

(36) Compounds of the invention have improved properties compared to compounds of the art. For example, as shown in FIG. 1, certain compounds of the invention have been shown to be more volatile than a representative compound of the art.

(37) Further, as shown in FIG. 2, below, certain compounds of the invention have been shown to be more stable than a representative compound of the art (shown in FIG. 3, below), thus permitting better use (longer lifetime of the material in the container) and also allows for the use of higher temperatures in deposition processes such as CVD and ALD.

(38) The compounds of Formula 1 are useful in chemical phase deposition processes such as atomic layer deposition (ALD) and chemical vapor deposition (CVD).

(39) In further embodiments of the invention, methods of forming metal-containing films by vapor deposition processes are provided. The methods comprise using at least one compound of Formula 1 together with one or more co-reagents, as disclosed herein.

(40) FIG. 4 shows a schematic of a CVD system used for exemplary thin film deposition. An inert carrier gas (1), such as Ar, is passed through a mass flow controller (2) at a controlled flow rate to bubbler (6), which contains a compound of Formula 1 (7) and carries the vaporized compound of Formula 1 to the reaction chamber (15). A liquid co-reagent (14) is delivered to the reaction chamber in a similar fashion, whereas a gaseous co-reagent is delivered directly to the reaction chamber at a controlled flow rate without going through the bubbler. The bubbler may be heated or cooled to obtain a suitable vapor pressure in the desired range. Typically, the temperature of the delivery line is higher than that of the bubbler by about 20 C°, so that the vapor does not condense before reaching reaction chamber. The compound of Formula 1 and the co-reagent are delivered simultaneously. In the reaction chamber, substrate(s) (16) rest on a pre-heated graphite holder (17) at a set temperature controlled by a heater (18) and a thermocouple (19). The pressure in the reaction chamber is controlled by a pressure regulating valve (20), which is connected to a vacuum pump. The delivered compound of Formula 1 and co-reagent react in the reaction chamber, deposit on substrate(s), and so form a thin film. The by-products of the reaction are pumped off under reduced pressure.

(41) For example, in a sixth embodiment of the invention the reaction of a compound of Formula 1 with co-reagents generates metal carbonyl hydrides, which can decompose cleanly and thermally to form substantially pure metal films, while the volatile carbonyl and hydrolyzed trialkyl silyl ligands evaporate and are removed.

(42) For the deposition of substantially pure metal films co-reagents include, but are not limited to, H2, ammonia, a lower alkyl amine, a lower alcohol, hydrazine and a substituted hydrazine.

(43) In a seventh embodiment of the invention the reaction of a compound of Formula 1 with co-reagents generates metal carbonyl oxides, which can decompose cleanly and thermally to form metal oxide films, while the volatile carbonyl and trialkyl silyl ligands evaporate and are removed.

(44) For the deposit of metal oxide films co-reagents include, but are not limited to, H.sub.2O, O.sub.2, O.sub.3, and a lower alcohol.

(45) In an eighth embodiment of the invention the reaction of a compound of Formula 1 with co-reagents generates metal carbonyl amides, which can decompose cleanly and thermally to form metal nitride films, while the volatile carbonyl and trialkyl silyl ligands evaporate and are removed.

(46) For the deposit of metal nitride films co-reagents include, but are not limited to, ammonia, a lower alkyl amine, a lower alcohol, hydrazine and a substituted hydrazine.

(47) In a ninth embodiment of the invention the reaction of a compound of Formula 1 with co-reagents generates metal carbonyl phosphide, which can decompose cleanly and thermally to form metal phosphide films, while the volatile carbonyl and trialkyl silyl ligands evaporate and are removed.

(48) For the deposit of metal phosphide films co-reagents include, but are not limited to, PH.sub.3 and a lower alkyl phosphine.

(49) In a tenth embodiment of the invention the reaction of a compound of Formula 1 with co-reagents generates metal carbonyl sulphide, which can decompose cleanly and thermally to form metal sulphide films, while the volatile carbonyl and trialkyl sily ligands evaporate and are removed.

(50) For the deposit of metal sulphide films co-reagents include, but are not limited to, H.sub.2S and a lower alkyl thiol.

(51) In an eleventh embodiment of the invention the reaction of a compound of Formula 1 with co-reagents generates metal carbonyl borides, which can decompose cleanly and thermally to form metal boride films, while the volatile carbonyl and trialkyl silyl ligands evaporate and are removed.

(52) For the deposit of metal boride films co-reagents include, but are not limited to, borane and a lower alkyl borane.

(53) In a further embodiment of the invention, the use of more than one compound of Formula 1, each having a different value of M, in the deposition processes disclosed herein results in the formation of films of substantially-pure metal alloys, mixed-metal oxides, mixed-metal nitrides, mixed-metal phosphides, mixed-metal borides or mixed-metal sulphides, the nature of the film formed being dependent upon the nature of the co-reagent used, as described herein.

(54) For example, in a twelfth embodiment of the invention the use of a cobalt-containing compound of Formula 1 together with a chromium-containing compound of Formula 1 will result in the deposition of a cobalt-chromium alloy.

(55) In further embodiments of the invention, methods of selective deposition are provided such that metal or metal nitride films are deposited selectively on certain substrates and not on other substrate materials.

(56) For example, a thirteenth embodiment of the invention involves the use of substrate materials having a surface with a strong affinity for the silyl (or germanyl or tin, as appropriate) ligand component of the compound of Formula 1 such that, after reaction of the compound of Formula 1 with the co-reagent, the silyl (or germanyl or tin, as appropriate) ligand attaches to the surface having such affinity, inhibiting the deposition of metal on that surface.

(57) Such substrate materials having an affinity include, but are not limited to, SiO.sub.2, SiN, TiN, and TaN.

(58) A fourteenth embodiment of the invention involves the use of substrate materials having an affinity for CO such that, after reaction of the compound of Formula 1 with the co-reagent, the metal carbonyl is bound to the surface having such affinity. The metal carbonyl is subsequently dissociated thermally, leaving the metal coating the surface whilst the CO is removed as gas.

(59) Such substrate materials having an affinity for CO include, but are not limited to, the nickel group metals Ni, Pd, Pt, cobalt group metals Co, Rh, Ir, and iron group metals Fe, Ru, and Os.

(60) FIG. 5 shows the binding energies of .sup.tBuMe.sub.2SiCo(CO).sub.4 to different surfaces. The more negative the energy, the better binding, meaning that the molecule will bind preferentially to Co or Cu, and thus the deposition will preferentially take place on that surface compared to silicon oxide where the binding is weak.

EXAMPLES

Example 1: Synthesis of EtMe.SUB.2.SiCo(CO).SUB.4

(61) 3 g of CO.sub.2(CO).sub.8 and 40 mL of dry pentane were charged into a 100 mL flask under N.sub.2, followed by the addition of 1.7 g of EtMe.sub.2SiH. After stirring for 1 hr, pentane and excess EtMe.sub.2SiH were removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. NMR confirmed the product to be EtMe.sub.2SiCo(CO).sub.4. TGA analysis and vapor pressure measurements showed that the material has a good volatility for vapor deposition applications, as shown in FIG. 6 and FIG. 7, respectively.

Example 2: Synthesis of Et.SUB.3.SiCo(CO).SUB.4

(62) 5 g of Co.sub.2(CO), and 60 mL of dry pentane were charged into a 100 mL flask under N.sub.2, followed by the addition of 3.7 g of Et.sub.3SiH. After stirring for 1 hr, pentane and excess Et.sub.3SiH were removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. NMR confirmed the product to be Et.sub.3SiCo(CO).sub.4, as shown in FIG. 8.

Example 3: Synthesis of .SUP.t.BuMe.SUB.2.SiCo(CO).SUB.4

(63) 3 g of CO.sub.2(CO).sub.B and 40 mL of dry pentane were charged into a 100 mL flask under N.sub.2, followed by the addition of 2 g of tBuMe.sub.2SiH. After stirring for 4 hr, pentane and excess tBuMe.sub.2SiH were removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. As shown in FIG. 9, NMR confirmed the product to be .sup.tBuMe.sub.2SiCo(CO).sub.4. TGA analysis and vapor pressure measurements showed that the material had good volatility for vapor deposition applications, as shown in FIG. 10 and FIG. 11.

(64) FIG. 12 shows that .sup.tBuMe.sub.2SiCo(CO).sub.4 has good thermal stability up to about 150° C., making it suitable for use in deposition.

Example 4: Synthesis of (Et.SUB.3.Si).SUB.2.Fe(CO).SUB.4

(65) 35 g of Et.sub.3SiH and 5 g of Fe(CO).sub.12 were charged in a bubbler. The bubbler was then heated at 120° C. for 36 hrs. Excess Et.sub.3SiH was removed under reduced pressure, followed by filtration to collect the product. NMR confirmed the product to be (Et.sub.3Si).sub.2Fe(CO).sub.4.

Example 5. Synthesis of Et.SUB.3.SiMn(CO).SUB.5

(66) 2.5 g Mn.sub.2(CO).sub.10 and 30 g of Et.sub.3SiH were charged in a bubbler. The bubbler was then heated at 170 C for 36 hrs. Excess Et.sub.3SiH was removed under reduced pressure, followed by distillation under reduced pressure to collect the product. NMR confirmed the product to be Et.sub.3SiMn(CO).sub.5.

Example 6. Synthesis of (DimethylphenylSi).SUB.2.W(CO).SUB.4

(67) 6.73 g of W(CO).sub.6 was suspended in 60 mL of dry dichloromethane. The suspension was cooled in a dry ice/acetone bath, followed by the addition of 1 mL Br.sub.2 diluted in 10 mL dichloromethane. The mixture was stirred for another 20 minutes. Dichloromethane was then pumped off in an ice/water bath to yield W.sub.2Br.sub.4(CO).sub.8.

(68) In another reaction flask, 10 g of PhMe.sub.2SiH was mixed with 60 mL of dimethoxyethane, followed by the addition of 6 g of potassium hydride. The reaction mixture was refluxed for 8 hrs, and then filtered to collect the liquid. The obtained liquid was then mixed with W.sub.2Br.sub.4(CO).sub.8 and stirred for 8 hrs in ice bath. Volatile solvent was pumped off. Sublimation was then carried out to collect (PhMe.sub.2Si).sub.2W(CO).sub.4.

Example 7: Synthesis of PhMe.SUB.2.SiCo(CO).SUB.4

(69) 5 g of Co.sub.2(CO).sub.8 and 40 mL of dry pentane were charged into a 100 mL flask under N.sub.2, followed by the addition of 4.38 g of PhMe.sub.2SiH. After stirring for 1 hr, pentane and excess PhMe2SiH were removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. NMR confirmed the product to be PhMe.sub.2SiCo(CO).sub.4, as shown in FIG. 13.

Example 8: Deposition of Co Thin Film Using EtMe.SUB.2.SiCo(CO).SUB.4 .Compound and NH.SUB.3 .Gas as Co-reagent

(70) EtMe.sub.2SiCo(CO).sub.4 compound in a bubbler was heated at 60° C., while the NH.sub.3 gas was at room temperature. The temperature of the substrate holder was 200° C. The carrier gas for Co reagent was Ar containing 5% H.sub.2. The flow rate of both was ca. 200 sccm. The pressure in the reaction chamber was 500 mbar. Substrates used were glass slide, Cu slide and TiN slide. Deposition was carried out for 6 minutes. All substrates were coated with shining Co thin film.

Example 9. Deposition of Co Thin Film Using Et.SUB.3.SiCo(CO).SUB.4 .Compound and Methanol as Co-Reagent

(71) Et.sub.3SiCo(CO).sub.4 compound in a bubbler was heated at 60° C., while methanol was cooled to 0° C. The temperature of the substrate holder was 200° C. The carrier gas for Co reagent was Ar containing 5% H.sub.2. The flow rate of both was ca. 200 sccm. The pressure in the reaction chamber was 500 mbar. Substrates used were glass slide, Cu slide and TiN slide. Deposition was carried out for 10 minutes. All substrates were coated with shining Co thin film.

Example 10. Deposition of Fe Thin Film Using (Et.SUB.3.Si).SUB.2.Fe(CO).SUB.4 .Compound and NH.SUB.3 .as Co-Reagent

(72) (Et.sub.3Si).sub.2Fe(CO).sub.4 compound in a bubbler was heated at 80° C., while the NH.sub.3 gas was at room temperature. The temperature of the substrate holder was 250° C. The carrier gas for Co reagent was Ar containing 5% H.sub.2. The flow rate of both was ca. 200 sccm. The pressure in the reaction chamber was 500 mbar. Substrates used were glass slide, Cu slide and TiN slide. Deposition was carried out for 10 minutes. Fe deposition was confirmed by EDX

Example 11. Deposition of CoO Thin Film Using EtMe.SUB.2.SiCo(CO).SUB.4 .Compound and O.SUB.2 .Gas as Co-reagent

(73) EtMe.sub.2SiCo(CO).sub.4 compound in bubbler was heated at 60° C. while the methanol was at room temperature. The temperature of the substrate holder was 200° C. The carrier gas for Co reagent was N.sub.2. The flow rate of both was ca. 200 sccm. The pressure in the reaction chamber was 500 mbar. Substrates used were glass slide, and TiN slide. Deposition was carried out for 6 minutes. All substrates were coated with CoO thin film. During the deposition air was present in the reactor system, resulting in higher oxygen content in the Co film that was deposited. This shows that CoO can be grown with 02 as co-reagent.

Example 12. Deposition of Co Thin Film Using .SUP.t.BuMe.SUB.2.SiCo(CO) Compound and NH.SUB.3./H.SUB.2 .Gas Mixture as Co-Reagent

(74) .sup.tBuMe.sub.2SiCo(CO).sub.4 compound in a bubbler was heated at 40° C., while the NH.sub.3/H.sub.2 gas mixture containing 25% H.sub.2 was kept at room temperature. The temperature of the reactor was 200° C. The carrier gas for Co reagent was N.sub.2. The flow rate of both was 200 sccm. The pressure in the reaction chamber was 100 Torr. Deposition was carried out for 30 minutes. A resistivity of 6.09×10.sup.−5 μΩcm was achieved.

(75) FIG. 14 shows the conductivity of the cobalt films obtained as a function of hydrogen/ammonia mixture, demonstrating that good quality films with high conductivities can be prepared using a hydrogen/ammonia mixture with greater than about 25% hydrogen.

(76) FIG. 15 shows that the growth rate flattens out when about 25-80% hydrogen is used with ammonia, confirming the conductivity data from FIG. 14. Film growth stability is observed.

Example 13. Selective Deposition of Co Thin Film on Co Seed Layers Using EtMe.SUB.2.SiCo(CO).SUB.4 .Compound and NH.SUB.3 .Gas as Co-Reagent

(77) EtMe.sub.2SiCo(CO).sub.4 compound in bubbler was heated at 40° C. while the NH.sub.3 gas was at room temperature. The temperature of the substrate holder was 200° C. The carrier gas for Co reagent was N.sub.2. The flow rate of both was ca. 200 sccm. The pressure in the reaction chamber was 90 torr. Initially low pressure CVD was carried out to deposit seed layers of Co metal on Cu Substrate. This was then followed with selective ALD growth of cobalt on the seed cobalt layers. During the CVD of cobalt seed, there was induction period on the SiO.sub.2 surface compared to Cu which allows for selective deposition of cobalt on copper as compared to silicon oxide, as shown in FIG. 16.

(78) The following reference characters are used in FIG. 4: 1 Inert carrier gas input; 2 Mass flow controller; 3 Valve controlling direct input of inert carrier gas to reaction chamber; 4 Valve controlling input of inert carrier gas to bubbler; 5 Valve controlling input of inert carrier gas containing vaporized precursor to reaction chamber; 6 Bubbler containing compound; 7 Compound; 8 Input of gaseous co-reagent or inert carrier gas for liquid co-reagent; 9 Mass flow controller; 10 Valve controlling direct input of gaseous co-reagent or inert carrier gas; 11 Valve controlling input of inert carrier gas to bubbler; 12 Valve controlling input of inert carrier gas containing vaporized co-reagent to reaction chamber; 13 Bubbler containing co-reagent; 14 Liquid co-reagent; 15 Quartz tube wall of reaction chamber; 16 Substrate; 17 Graphite substrate holder with heater and thermocouple; 18 Heater; 19 Thermocouple; 20 Pressure regulating valve to vacuum pump controlling gas pressure in reaction chamber; and 21 Metal flanges for reaction chamber.

(79) The scope of the claims should not be limited by the illustrated embodiments set forth as examples, but should be given the broadest interpretation consistent with a purposive construction of the claims in view of the description as a whole.