Hafnium or zirconium oxide coating
The invention concerns an optical coating ( 3, 3 ′), having a high refractive index and good optical properties (i.e., low absorption and scatter) and limited internal stresses in a spectral range extending from the visible to the near UV range (i.e., up to a wavelength of 220 nm). The coating ( 3, 3 ′) according to the invention consists of a hafnium- or zirconium-containing oxide Hf x Si y O z or Zr x Si y O z containing an silicon fraction (y) between 1 at. % and 10 at. %, especially between 1.5 at. % and 3 at. %.
1. Coating comprising a composition having the formula Hf x Si y O z or Zr x Si y O z , wherein x=100−(y+z) at. %, y=1.5 at. % to 3 at. %, and z=65 at. % to 68 at. %; wherein the formula Hf x Si y O z represents HfO 2 with part of the hafnium replaced by silicon; and wherein the formula Zr x Si y O z represents ZrO 2 with part of the zirconium replaced by silicon.
2. Coating according to claim 1 , wherein z=66.7 at. % in the formula Hf x Si y O z or z=66.66 at. % in the formula Zr x Si y O z .
3. Coating according to claim 2 , wherein the composition has the formula Zr 30.83 Si 2.5 O 66.66 .
4. Method of production of coating according to claim 1 , wherein the coating is produced by magnetron sputtering.
5. Method according to claim 4 , wherein the coating is produced by reactive co-magnetron sputtering of Hf or Zr and Si.
6. Method according to claim 4 , wherein the coating is produced by reactive co-magnetron sputtering of HfSi or ZrSi and Si.
7. Method according to claim 4 , wherein the coating is produced by reactive co-magnetron sputtering of Hf x Si y O z or Zr x Si y O z and Si.
8. Method according to claim 4 , wherein the coating is produced by reactive magnetron sputtering using an Hf- or Zr- and Si-containing compound target.
9. Method according to claim 4 , wherein the coating is produced by partially reactive magnetron sputtering using a conducting Hf x Si y O z or Zr x Si y O z compound target.
10. Method according to claim 4 , wherein the magnetron sputtering is accompanied by reactive in situ plasma treatment.
11. Method according to claim 4 , wherein the Si fraction is set so that the coating has minimal extinction with simultaneously low internal layer stress and high refractive index.