Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals
Lutetium aluminum garnet (LuAG) is the most promising candidate for a high-index lens material for use in microlithographic imaging lenses. In the deep ultraviolet spectral range the transmission of high-purity LuAG was measured using monochromatized synchrotron radiation. In the vicinity of the ban...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2010
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| Online Access: | http://hdl.handle.net/1721.1/58712 |
| _version_ | 1826188648354152448 |
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| author | Liberman, Vladimir Letz, M. Gottwald, A. Richter, M. Parthier, L. |
| author2 | Lincoln Laboratory |
| author_facet | Lincoln Laboratory Liberman, Vladimir Letz, M. Gottwald, A. Richter, M. Parthier, L. |
| author_sort | Liberman, Vladimir |
| collection | MIT |
| description | Lutetium aluminum garnet (LuAG) is the most promising candidate for a high-index lens material for use in microlithographic imaging lenses. In the deep ultraviolet spectral range the transmission of high-purity LuAG was measured using monochromatized synchrotron radiation. In the vicinity of the band gap below 7.8 eV, a scaling behavior of the absorption as a function of photon energy was observed. Temperature-dependent measurements allowed us to distinguish different absorption mechanisms which differ by their ability to couple to phonon excitations. Interpreting the Urbach tails measured at different temperatures, it was shown that the temperature independent tail is due to defects in the lattice, whereas the temperature-dependent part originates from the short term localization of exciton modes coupling to lattice distortions. These results allowed us to extrapolate the maximum transmittance which can be obtained with LuAG crystals at the lithographic wavelength of 193.39 nm. Accurate determination of the maximum transmission limit is critical in deciding whether the material can meet industry’s specification for 193-nm-based high-index lithography. |
| first_indexed | 2024-09-23T08:02:53Z |
| format | Article |
| id | mit-1721.1/58712 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:02:53Z |
| publishDate | 2010 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/587122022-09-30T01:55:58Z Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals Liberman, Vladimir Letz, M. Gottwald, A. Richter, M. Parthier, L. Lincoln Laboratory Liberman, Vladimir Liberman, Vladimir Lutetium aluminum garnet (LuAG) is the most promising candidate for a high-index lens material for use in microlithographic imaging lenses. In the deep ultraviolet spectral range the transmission of high-purity LuAG was measured using monochromatized synchrotron radiation. In the vicinity of the band gap below 7.8 eV, a scaling behavior of the absorption as a function of photon energy was observed. Temperature-dependent measurements allowed us to distinguish different absorption mechanisms which differ by their ability to couple to phonon excitations. Interpreting the Urbach tails measured at different temperatures, it was shown that the temperature independent tail is due to defects in the lattice, whereas the temperature-dependent part originates from the short term localization of exciton modes coupling to lattice distortions. These results allowed us to extrapolate the maximum transmittance which can be obtained with LuAG crystals at the lithographic wavelength of 193.39 nm. Accurate determination of the maximum transmission limit is critical in deciding whether the material can meet industry’s specification for 193-nm-based high-index lithography. 2010-09-27T14:46:36Z 2010-09-27T14:46:36Z 2010-04 2010-01 Article http://purl.org/eprint/type/JournalArticle 1098-0121 1550-235X http://hdl.handle.net/1721.1/58712 Letz, M. et al. “Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals.” Physical Review B 81.15 (2010): 155109. © 2010 The American Physical Society. en_US http://dx.doi.org/10.1103/PhysRevB.81.155109 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Liberman, Vladimir Letz, M. Gottwald, A. Richter, M. Parthier, L. Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals |
| title | Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals |
| title_full | Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals |
| title_fullStr | Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals |
| title_full_unstemmed | Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals |
| title_short | Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals |
| title_sort | temperature dependent urbach tail measurements of lutetium aluminum garnet single crystals |
| url | http://hdl.handle.net/1721.1/58712 |
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