Method of generating high purity bismuth oxide
View Patent ↗A method for forming and protecting high quality bismuth oxide films comprises depositing a transparent thin film on a substrate comprising one of Si, alkali metals, or alkaline earth metals. The transparent thin film is stable at room temperature and at higher temperatures and serves as a diffusion barrier for the diffusion of impurities from the substrate into the bismuth oxide. Reactive sputtering, sputtering from a compound target, or reactive evaporation are used to deposit a bismuth oxide film above the diffusion barrier.
1. A method for forming a bismuth oxide film stack comprising:
providing a transparent substrate;
forming a first layer above the transparent substrate, wherein the first layer is operable as a diffusion barrier in the bismuth oxide film stack, and wherein the first layer comprises at least one of tin-doped magnesium oxide (Sn:MgOx) or silicon titanium oxide (SiTiO x );
forming a bismuth oxide layer above the first layer, wherein the bismuth oxide layer is formed using a reactive sputtering technique; and
annealing the transparent substrate, the first layer, and the bismuth oxide layer.
2. The method of claim 1 wherein the first layer has a thickness of between about 0.5 nm and about 10 nm.
3. The method of claim 2 wherein the first layer comprises silicon titanium oxide (SiTiO x ).
4. The method of claim 1 wherein the first layer has a thickness between about 1 nm and about 5 nm, and the bismuth oxide layer has a thickness of between about 10 nm and about 1000 nm.
5. The method of claim 4 wherein the first layer comprises tin-doped magnesium oxide (Sn:MgOx).
6. The method of claim 1 wherein the bismuth oxide has a thickness of about 100 nm.
7. The method of claim 1 wherein the anneal treatment is performed at a temperature of about 650° C.
8. The method of claim 1 wherein the anneal treatment is performed for about 8 minutes.
9. The method of claim 1 wherein the anneal treatment is performed in an atmosphere comprising air.
10. The method of claim 1 wherein the transparent substrate comprises at least one of Si, alkali metals, or alkaline earth metals.
11. A method for forming a bismuth oxide film stack comprising:
providing a transparent substrate;
forming a dielectric layer above the transparent substrate, wherein the dielectric layer comprises silicon titanium oxide (SiTiO x );
forming a bismuth oxide layer above the dielectric layer, wherein the bismuth oxide layer is formed using a reactive sputtering technique; and
annealing the transparent substrate, the dielectric layer, and the bismuth oxide layer.
12. The method of claim 11 wherein the dielectric layer has a thickness of between about 0.5 nm and about 10 nm.
13. The method of claim 12 wherein the dielectric layer has a thickness between about 1 nm and about 5 nm.
14. The method of claim 11 wherein the bismuth oxide layer has a thickness of between about 10 nm and about 1000 nm.
15. The method of claim 11 , wherein the transparent substrate comprises glass.