Heat stabilized sub-stoichiometric dielectrics
View Patent ↗A sub-stoichiometric oxide, nitride or oxynitride layer in an optical stack, alone or in direct contact with one or two stabilizing layers, stabilizes the optical properties of the stack. The stabilizing layer(s) can stabilize the chemistry and optical properties of the sub-stoichiometric layer during heating. The change in optical characteristics of the sub-stoichiometric layer upon heating can counter the change in optical characteristics of the rest of the optical stack.
1. An optical stack comprising a sub-stoichiometric layer in direct contact with a stabilizing layer, wherein
the sub-stoichiometric layer consists of
a homogeneous sub-stoichiometric composition selected from the group consisting of oxides, nitrides and oxynitrides, where
the sub-stoichiometric composition comprises at least one element selected from the group consisting of metal elements and semiconductor elements, and
the sub-stoichiometric composition further comprises a sub-stoichiometric amount of at least one element selected from the group consisting of oxygen and nitrogen;
the stabilizing layer comprises
the at least one element selected from the group consisting of metal elements and semiconductor elements, and
a stoichiometric amount of the at least one element selected from the group consisting of oxygen and nitrogen; and
the sub-stoichiometric layer is from 10 to 100 nm thick and thicker than the stabilizing layer.
2. The optical stack according to claim 1 , wherein the stabilizing layer is from 1 to 10 nm thick.
3. The optical stack according to claim 1 , wherein
the metal elements are selected from the group consisting of transition metals, Mg, Zn, Al, In, Sn, Sb and Bi; and
the semiconductor elements are selected from the group consisting of Si and Ge.
4. The optical stack according to claim 1 , wherein
the metal elements are selected from the group consisting of Mg, Y, Ti, Zr, Nb, Ta, W, Zn, Al, In, Sn, Sb and Bi; and
the semiconductor elements are selected from the group consisting of Si and Ge.
5. The optical stack according to claim 1 , wherein the at least one element selected from the group consisting of metal elements and semiconductor elements comprises Si and Al.
6. The optical stack according to claim 1 , wherein the sub-stoichiometric composition comprises at least two members of the group consisting of oxides, nitrides and oxynitrides.
7. The optical stack according to claim 1 , wherein the index of refraction of the sub-stoichiometric layer is higher than the index of refraction of the stabilizing layer.
8. The optical stack according to claim 1 , wherein the sub-stoichiometric layer has an index of refraction, n, such that n≧2.3.
9. The optical stack according to claim 1 , wherein the sub-stoichiometric layer has an extinction coefficient, k, such that 0.03≦k≦0.15.
10. The optical stack according to claim 1 , wherein
the optical stack is on a transparent substrate;
the optical stack further comprises a metal layer; and
the sub-stoichiometric layer and the stabilizing layer are between the transparent substrate and the metal layer.
11. The optical stack according to claim 10 , where the transparent substrate comprises a glass.
12. The optical stack according to claim 11 , wherein
the optical stack is produced by a process comprising tempering the optical stack on the transparent substrate; and
the glass side reflection tempering color shift of the optical stack on the transparent glass substrate is 3.0 or less.
13. The optical stack according to claim 11 , wherein
the optical stack is produced by a process comprising tempering the optical stack on the transparent substrate; and
the optical stack side reflection tempering color shift of the optical stack on the transparent glass substrate is 3.7 or less.
14. The optical stack according to claim 10 , wherein the metal layer comprises Ag.
15. The optical stack according to claim 10 , wherein
the optical stack further comprises another metal layer; and
the sub-stoichiometric layer and the stabilizing layer are between the metal layer and the other metal layer.
16. The optical stack according to claim 1 , wherein
the optical stack is on a transparent substrate;
the optical stack further comprises a metal layer; and
the sub-stoichiometric layer and the stabilizing layer are outward from the substrate from the metal layer.
17. A method of making an optical stack, the method comprising
laminating a stabilizing layer and a sub-stoichiometric layer; and
producing the optical stack of claim 1 .
18. An optical stack comprising a sub-stoichiometric layer sandwiched between and in direct contact with a first stabilizing layer and a second stabilizing layer, wherein
the sub-stoichiometric layer consists of
a sub-stoichiometric composition selected from the group consisting of oxides, nitrides and oxynitrides, where
the sub-stoichiometric composition comprises at least one element selected from the group consisting of metal elements and semiconductor elements, and
the sub-stoichiometric composition further comprises a sub-stoichiometric amount of at least one element selected from the group consisting of oxygen and nitrogen; and
the first stabilizing layer and the second stabilizing layer each comprises
the at least one element selected from the group consisting of metal elements and semiconductor elements, and
a stoichiometric amount of the at least one element selected from the group consisting of oxygen and nitrogen; the sub-stoichiometric layer is from 10 to 100 nm thick and thicker than both the first and second stabilizing layers.
19. The optical stack according to claim 18 , wherein the first stabilizing layer and the second stabilizing layer have the same composition.
20. The optical stack according to claim 18 , wherein the first stabilizing layer and the second stabilizing layer have different compositions.
21. The optical stack according to claim 18 , wherein the sub-stoichiometric layer is homogeneous.
22. The optical stack according to claim 18 , wherein the sub-stoichiometric composition comprises at least two members of the group consisting of oxides, nitrides and oxynitrides.
23. The optical stack according to claim 18 , wherein
the metal elements are selected from the group consisting of transition metals, Mg, Zn, Al, In, Sn, Sb and Bi; and
the semiconductor elements are selected from the group consisting of Si and Ge.
24. The optical stack according to claim 18 , wherein
the metal elements are selected from the group consisting of Mg, Y, Ti, Zr, Nb, Ta, W, Zn, Al, In, Sn, Sb and Bi; and
the semiconductor elements are selected from the group consisting of Si and Ge.
25. The optical stack according to claim 18 , wherein the at least one element selected from the group consisting of metal elements and semiconductor elements comprises Si and Al.
26. The optical stack according to claim 18 , wherein the index of refraction of the sub-stoichiometric layer is higher than the index of refraction of each of the first stabilizing layer and the second stabilizing layer.
27. The optical stack according to claim 18 , wherein the sub-stoichiometric layer has an index of refraction, n, such that n≧2.3.
28. The optical stack according to claim 18 , wherein the sub-stoichiometric layer has an extinction coefficient, k, such that 0.03≦k≦0.15.
29. The optical stack according to claim 18 , wherein the first stabilizing layer is from 1 to 10 nm thick.
30. The optical stack according to claim 29 , wherein the second stabilizing layer is from 1 to 10 nm thick.
31. The optical stack according to claim 18 , wherein
the optical stack is on a transparent substrate;
the optical stack further comprises a metal layer; and
the first stabilizing layer, the sub-stoichiometric layer, and the second stabilizing layer are between the transparent substrate and the metal layer.
32. The optical stack according to claim 31 , wherein the transparent substrate comprises a glass.
33. The optical stack according to claim 31 , wherein the metal layer comprises Ag.
34. The optical stack according to claim 31 , wherein
the optical stack further comprises another metal layer; and
the first stabilizing layer, the sub-stoichiometric layer, and the second stabilizing layer are between the metal layer and the other metal layer.
35. The optical stack according to claim 18 , wherein
the optical stack is on a transparent substrate;
the optical stack further comprises a metal layer; and
the first stabilizing layer, the sub-stoichiometric layer, and the second stabilizing layer are outward from the substrate from the metal layer.
36. A method of making an optical stack, the method comprising
laminating a first stabilizing layer, a sub-stoichiometric layer and a second stabilizing layer; and
producing the optical stack of claim 18 .