Method of interlayer mediated epitaxy of cobalt silicide from low temperature chemical vapor deposition of cobalt

Claim 2

A process for forming an epitaxial cobalt disilicide layer on a silicon substrate comprising: (a) vaporizing a cobalt source precursor; (b) decomposing said cobalt source precursor on the silicon substrate to form on the silicon substrate an ultrathin interfacial layer and a cobalt layer over the ultrathin interfacial layer; (c) forming, over the cobalt layer, a capping layer comprising at least one of a refractory metal, a refractory metal nitride, a refractory metal carbide, a binary nitride of a refractory metal, a binary carbide of a refractory metal, a ternary nitride of a refractory metal and a ternary carbide of a refractory metal; and (d) annealing at a temperature sufficiently high and for a period sufficiently long to form the epitaxial cobalt disilicide layer on the silicon substrate.

Claim 3

A process according to claim 1 wherein the cobalt source precursor is selected from cobalt tricarbonyl nitrosyl; cobalt tetracarbonyl iodide, cobalt tetracarbonyl trichlorosilane, carbonyl chloride tris(trimethylphosphine) cobalt, cobalt tricarbonyl-hydrotributylphosphine, acetylene dicobalt hexacarbonyl and acetylene dicobalt pentacarbonyl triethylphosphine.

Claim 4

A process according to claim 1 wherein the cobalt source precursor is cobalt tricarbonyl nitrosyl.

Claim 5

A process according to claim 1 wherein the refractory metal is chosen from titanium, tantalum, and tungsten.

Claim 6

A process according to claim 4 wherein the refractory metal is titanium.

Claim 7

A process according to claim 1 wherein the refractory metal nitride is titanium nitride.

Claim 8

A process according to claim 1 wherein the capping layer comprises titanium and titanium nitride.

Claim 9

A process according to claim 7 wherein the capping layer comprises a layer of titanium nitride over a layer of titanium.

Claim 10

A process according to claim 1 wherein the capping layer is formed by physical vapor deposition.

Claim 11

A process according to claim 1 wherein the silicon substrate is heated to a temperature ranging from 300° C. to 600° C. in order to decompose the cobalt source precursor on the silicon substrate.

Claim 12

A process according to claim 10 wherein the silicon substrate is heated to a temperature of about 390° C. in order to decompose the cobalt source precursor on the silicon substrate.

Claim 13

A process according to claim 1 wherein annealing is performed at a temperature ranging from about 700° C. to 1000° C.

Claim 14

A process according to claim 12 wherein annealing is performed at about 725° C.

Claim 15

A process according to claim 1 wherein annealing is performed for a period ranging from about 30 seconds to about 90 seconds.

Claim 16

A process according to claim 14 wherein annealing is performed for about 30 seconds.

Claim 17

A process according to claim 1 wherein the cobalt layer has a thickness of about 30 nm.

Claim 18

A process for forming an epitaxial cobalt disilicide layer on a silicon substrate comprising: (a) vaporizing a cobalt source precursor comprising cobalt tricarbonyl nitrosyl; (b) decomposing said cobalt source precursor on the silicon substrate to form on the silicon substrate an ultrathin interfacial layer and a cobalt layer over the ultrathin interfacial layer; (c) forming, over the cobalt layer, a capping layer comprising a layer of titanium nitride over a layer of titanium; and (d) annealing at a temperature of about 725° C. for a period of about 30 seconds.

Claim 19

A process for forming an epitaxial cobalt disilicide layer on a silicon substrate comprising: (a) vaporizing a cobalt source precursor comprising cobalt tricarbonyl nitrosyl; (b) decomposing said cobalt source precursor on the silicon substrate to form on the silicon substrate an ultrathin interfacial layer and a cobalt layer over the ultrathin interfacial layer; (c) forming, over the cobalt layer, a capping layer comprising a layer of titanium nitride over a layer of titanium; and (d) annealing at a temperature of about 725° C. for a period of about 30 seconds.

Claim 20

An ALCVD process for the deposition of a layer comprising cobalt on a surface of a substrate in a deposition chamber, the process comprising the sequential steps of: (a) vaporizing a cobalt source precursor; (b) pulsing the cobalt source precursor into the deposition chamber; (c) contacting a surface of the substrate with the cobalt source precursor or a composition derived therefrom; (d) pulsing an inert gas into the deposition chamber; and (e) decomposing the cobalt source precursor or composition derived therefrom to form a layer comprising cobalt on the surface of the substrate.

Claim 21

An ALCVD process for the deposition of a layer comprising cobalt on a surface of a substrate in a deposition chamber, the process comprising the sequential steps of: (a) vaporizing a cobalt source precursor; (b) pulsing the cobalt source precursor into the deposition chamber; (c) contacting a surface of the substrate with the cobalt source precursor or a composition derived therefrom; (d) pulsing an inert gas into the deposition chamber; and (e) decomposing the cobalt source precursor or composition derived therefrom to form a layer comprising cobalt on the surface of the substrate.

Claim 22

An ALCVD process according to claim 18 additionally comprising the step of: pulsing a reactant gas into the deposition chamber; said step being performed after pulsing an inert gas into the deposition chamber and before decomposing the cobalt source precursor.

Claim 23

An ALCVD process according to claim 19 additionally comprising, after decomposing the cobalt source precursor, pulsing an inert gas into the deposition chamber.

Claim 24

An ALCVD process according to claim 18 wherein the substrate is heated to a temperature ranging from about 300° C. to about 600° C.

Claim 25

An ALCVD process according to claim 18 wherein the substrate is heated to a temperature of 390° C.

Claim 26

An ALCVD process according to claim 20 wherein the steps are performed repeatedly in sequence to form a plurality of cobalt layers on the substrate.

Claim 27

An ALCVD process according to claim 18 wherein the cobalt source precursor is selected from cobalt tricarbonyl nitrosyl, cobalt tetracarbonyl iodide, cobalt tetracarbonyl trichlorosilane, carbonyl chloride tris(trimethylphosphine) cobalt, cobalt tricarbonyl-hydrotributylphosphine, acetylene dicobalt hexacarbonyl and acetylene dicobalt pentacarbonyl triethylphosphine.

Claim 28

An ALCVD process according to claim 24 wherein the cobalt source precursor is cobalt tricarbonyl nitrosyl.

Claim 29

An ALCVD process according to claim 18 wherein the reactant gas is hydrogen.

Claim 30

An ALCVD process according to claim 18 wherein a carrier gas is pulsed into the deposition chamber with the cobalt source precursor.

Claim 31

An ALCVD process for forming an epitaxial cobalt disilicide layer on a silicon substrate, the process comprising the sequential steps of: (a) vaporizing a cobalt source precursor; (b) pulsing the cobalt source precursor into the deposition chamber; (c) contacting a surface of the substrate with the cobalt source precursor or a composition derived therefrom; (d) pulsing an inert gas into the deposition chamber; (e) decomposing the cobalt source precursor or composition derived therefrom to form a layer comprising cobalt on the surface of the substrate; (f) forming a capping layer comprising at least one of a refractory metal, a refractory metal nitride, a refractory metal carbide, a binary nitride of a refractory metal, a binary carbide of a refractory metal, a ternary nitride of a refractory metal and a ternary carbide of a refractory metal; and (g) annealing at a temperature sufficiently high and for a period sufficiently long to form an epitaxial cobalt disilicide layer.

Claim 32

An ALCVD process for forming an epitaxial cobalt disilicide layer on a silicon substrate, the process comprising the sequential steps of: (a) vaporizing a cobalt source precursor; (b) pulsing the cobalt source precursor into the deposition chamber; (c) contacting a surface of the substrate with the cobalt source precursor or a composition derived therefrom; (d) pulsing an inert gas into the deposition chamber; (e) decomposing the cobalt source precursor or composition derived therefrom to form a layer comprising cobalt on the surface of the substrate; (f) forming a capping layer comprising at least one of a refractory metal, a refractory metal nitride, a refractory metal carbide, a binary nitride of a refractory metal, a binary carbide of a refractory metal, a ternary nitride of a refractory metal and a ternary carbide of a refractory metal; and (g) annealing at a temperature sufficiently high and for a period sufficiently long to form an epitaxial cobalt disilicide layer.

Claim 33

An ALCVD process according to claim 28 wherein annealing is performed at a temperature ranging from about 700° C. to 900° C.

Claim 34

An ALCVD process according to claim 29 wherein annealing is performed at about 725° C.

Claim 35

An ALCVD process according to claim 28 wherein annealing is performed for a period ranging from about 30 seconds to about 180 seconds.

Claim 36

An ALCVD process according to claim 31 wherein annealing is performed for about 30 seconds.

Claim 37

An ALCVD process according to claim 28 wherein the cobalt layer has a thickness of about 30 nm.