CIG sputtering target and methods of making and using thereof
A sputtering target includes a copper indium gallium sputtering target material on a backing structure. The sputtering target material has a density of at least 100% or more as defined by the rule of mixtures applied to densities of component elements of the sputtering target material. The sputtering target material has an overall uniform composition.
1 . A sputtering target, comprising: a copper indium gallium sputtering target material on a backing structure,
wherein:
the sputtering target material has a density of at least 100% or more as defined by the rule of mixtures applied to densities of component elements of the sputtering target material; and
the sputtering target material has an overall uniform composition.
2 . A sputtering target as claimed in claim 1 , wherein the backing structure comprises a hollow tube and the sputtering target material is formed over an outer surface of the hollow tube.
3 . A sputtering target as claimed in claim 1 , wherein the backing structure has a planar shape.
4 . A sputtering target as claimed in claim 1 , wherein:
from 0% to 10% of primary phase regions in the sputtering target material are of a size greater than 100 μm in any random 1 cm by 1 cm area of the sputtering target;
an average primary phase region in the sputtering target material is of a size not greater than 40 μm; and
the sputtering target material has an overall uniform composition.
5 . A sputtering target as claimed in claim 1 , wherein the sputtering target material has an overall uniform composition of about 29-39 wt % copper, about 49-62 wt % indium, and about 8-16 wt % gallium.
6 . A sputtering target as claimed in claim 1 , wherein:
the sputtering target material does not contain inclusions or pores greater than a 100 μm diameter sphere in size; and
the sputtering target material does not contain pores or cracks having a distance larger than 1000 μm.
7 . A sputtering target as claimed in claim 6 , wherein:
the sputtering target material does not contain inclusions or pores greater than a 50 μm diameter sphere in size; and
the sputtering target material does not contain pores or cracks having a distance larger than 500 μm.
8 . A sputtering target as claimed in claim 1 , wherein:
the sputtering target material has a density of 100% to 107% as determined by a rule of mixtures; and
the sputtering target material contains 0 to 3 vol % porosity.
9 . A method of making a sputtering target, comprising:
providing a backing structure, and
forming a copper indium gallium sputtering target material on the backing structure,
wherein:
the sputtering target material has a density at least 100% or more as defined by the rule of mixtures applied to the densities of the component elements; and
the sputtering target material has an overall uniform composition.
10 . A method as claimed in claim 9 , wherein the backing structure comprises a hollow tube and the sputtering target material is formed on an outer surface of the hollow tube.
11 . A method as claimed in claim 9 , wherein the backing structure has a planar shape.
12 . A method as claimed in claim 9 , wherein the sputtering target material is formed onto the backing structure by direct forging.
13 . A method as claimed in claim 12 , wherein the direct forging comprises forcing a semi-solid or a solid billet onto a cylindrical backing tube.
14 . A method as claimed in claim 9 , wherein the sputtering target material is formed by a welding process.
15 . A method as claimed in claim 14 , wherein the sputtering target material is formed by electrical or gas welding.
16 . A method as claimed in claim 14 , wherein the sputtering target material is formed by laser welding or electron beam welding.
17 . A method as claimed in claim 9 , wherein the sputtering target material is formed by powder metallurgy.
18 . A method as claimed in claim 9 , wherein the sputtering target material is formed by casting or molding copper indium gallium material in a thixotropic state.
19 . A method as claimed in claim 9 , wherein the sputtering target material is formed by metal injection molding.
20 . A method as claimed in claim 9 , wherein the sputtering target material is formed by zone melting.
21 . A method as claimed in claim 9 , wherein the sputtering target material is formed by vacuum casting.
22 . A method as claimed in claim 9 , wherein the sputtering target material is formed by strip casting.
23 . A method as claimed in claim 9 , wherein the sputtering target material is formed by backwards flow pressing.
24 . A method as claimed in claim 9 , wherein the sputtering target material is formed by dip casting.
25 . A method as claimed in claim 9 , wherein the sputtering target material is formed by forming at least one hollow ring or tube shaped segment of the sputtering target material.
26 . A method as claimed in claim 9 , wherein the sputtering target material is formed by directly forming the sputtering target material onto a cylindrical backing structure.
27 . A method as claimed in claim 9 , wherein the sputtering target material is formed by uniaxial pressing of at least one hollow ring or tube segment of the sputtering target material.
28 . A method as claimed in claim 27 , wherein the step of uniaxial pressing comprises providing copper indium gallium powder around a cylindrical backing structure and uniaxially pressing the powder substantially parallel to a longitudinal axis of the cylindrical backing structure.
29 . A method as claimed in claim 27 , wherein the step of uniaxial pressing comprises uniaxially pressing copper indium gallium powder in a direction substantially parallel to a longitudinal axis of the at least one segment and followed by joining the at least one segment to the cylindrical backing structure.
30 . A method as claimed in claim 9 , further comprising providing a bond coat comprising indium, gallium or indium gallium alloy between the backing structure and the sputtering target material.
31 . A method as claimed in claim 9 , wherein the sputtering target material is formed by rapid cooling or rapid solidification of the sputtering target material on the backing structure at rate of 1-100° C./s.
32 . A method as claimed in claim 9 , wherein:
from 0% to 10% of primary phase regions in the sputtering target material are of a size greater than 100 μm in any random 1 cm by 1 cm area of the sputtering target;
an average primary phase region in the sputtering target material is of a size not greater than 40 μm; and
the sputtering target material has an overall uniform composition.
33 . A method as claimed in claim 9 , wherein the sputtering target material has an overall uniform composition of about 29-39 wt % copper, about 49-62 wt % indium, and about 8-16 wt % gallium.
34 . A method as claimed in claim 9 , wherein:
the sputtering target material does not contain inclusions or pores greater than a 100 μm diameter sphere in size; and
the sputtering target material does not contain pores or cracks having a distance larger than 1000 μm.
35 . A method as claimed in claim 9 , wherein:
the sputtering target material has a density of 100% to 107% as determined by a rule of mixtures;
the sputtering target material contains 0 to 3 vol % porosity;
the sputtering target material does not contain inclusions or pores greater than a 50 μm diameter sphere in size; and
the sputtering target material does not contain pores or cracks having a distance larger than 500 μm.
36 . A method of making a sputtering target, comprising:
providing a backing structure, and
forming a copper indium gallium sputtering target material on the backing structure,
wherein the sputtering target material is formed on the backing structure by a process selected from the group consisting of:
direct forging,
welding,
casting or molding the sputtering target material in a thixotropic state,
metal injection molding,
zone melting,
vacuum casting,
strip casting,
backwards flow pressing,
roll dip casting, and
uniaxial pressing of a powder to form at least one hollow ring or tube segment of the sputtering target material.
37 . A method as claimed in claim 36 , wherein:
from 0% to 10% of primary phase regions in the sputtering target material are of a size greater than 100 μm in any random 1 cm by 1 cm area of the sputtering target;
an average primary phase region in the sputtering target material is of a size not greater than 40 μm; and
the sputtering target material has an overall uniform composition.
38 . A method as claimed in claim 36 , wherein the sputtering target material has an overall uniform composition of about 29-39 wt % copper, about 49-62 wt % indium, and about 8-16 wt % gallium.
39 . A method as claimed in claim 36 , wherein:
the sputtering target material has a density of 100% to 107% as determined by a rule of mixtures;
the sputtering target material contains 0 to 3 vol % porosity;
the sputtering target material does not contain inclusions or pores greater than a 100 μm diameter sphere in size; and
the sputtering target material does not contain pores or cracks having a distance larger than 1000 μm.
40 . A method as claimed in claim 36 , wherein:
the sputtering target material has a density of 100% to 107% as determined by a rule of mixtures;
the sputtering target material contains 0 to 3 vol % porosity;
the sputtering target material does not contain inclusions or pores greater than a 50 μm diameter sphere in size; and
the sputtering target material does not contain pores or cracks having a distance larger than 500 μm.
41 . A method as claimed in claim 36 , further comprising forming at least one bonding layer between the backing structure and the sputtering target material.
42 . A method as claimed in claim 36 , wherein:
the step of forming the at least one bonding layer comprises forming a Cu or Cu alloy compatible layer over the backing structure and forming a protective liquid In, Ga or In—Ga alloy film over the compatible layer; and
the In, Ga or In—Ga alloy film forms a Cu—In—Ga diffusion bond layer between the copper indium gallium sputtering target material and the compatible layer.
43 . A method as claimed in claim 18 , wherein:
the backing structure comprises a stainless steel backing structure.
44 . A method as claimed in claim 43 , wherein:
the step of forming the at least one bonding layer further comprises forming a nickel or aluminum alloy bond coat layer between the compatible layer and the backing structure.
45 . A method as claimed in claim 36 , wherein:
the step of forming the at least one bonding layer comprises forming a protective liquid In, Ga or In—Ga alloy film over a Cu or Cu alloy backing structure; and
a Cu—In—Ga diffusion bond layer is formed between the copper indium gallium sputtering target material and the backing structure.