Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition
Autor(a) principal: | |
---|---|
Data de Publicação: | 2005 |
Outros Autores: | , , , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/204762 |
Resumo: | We report the optical properties of unannealed hafnium–aluminate HfAlO films grown by atomic layer chemical vapor deposition ALCVD and correlate them with the aluminum contents in the films. Vacuum ultraviolet spectroscopic ellipsometry VUV-SE , high-resolution transmission electron microscopy HRTEM , channeling Rutherford backscattering spectrometry RBS , and resonant nuclear reaction analysis NRA were employed to characterize these films. In the analyses of ellipsometry data, a double Tauc–Lorentz dispersion produces a best fit to the experimental VUV-SE data. As a result, the determined complex pseudodielectric functions of the films clearly exhibit a dependency on the aluminum densities measured by RBS and NRA. We show that the optical fundamental band gap Eg shifts from 5.56±0.05 eV for HfO2 to 5.92±0.05 eV for HfAlO. The latter was grown by using an equal number of pulses of H2O/HfCl4 and H2O/TMA trimethylaluminum precursors in each deposition cycle for HfO2 and Al2O3, respectively. The shift of Eg to higher photon energies with increasing aluminum content indicates that intermixing of HfO2 and Al2O3 occurred during the ALCVD growth process. We found that Eg varies linearly with the mole fraction x of Al2O3 in the alloy HfO2 x Al2O3 1−x, but has a parabolic dependency with the aluminum density. We also observed a consistent decrease in the magnitudes of the real 1 and imaginary 2 part of of HfAlO films with respect to those of HfO2 as the Al density increased. The absence of the 5.7 eV peak in the spectrum, which was previously reported for polycrystalline HfO2 films, indicates that these films are amorphous as confirmed by their HRTEM images. |
id |
UFRGS-2_5577d4e2c9913df3d964a904cfed4786 |
---|---|
oai_identifier_str |
oai:www.lume.ufrgs.br:10183/204762 |
network_acronym_str |
UFRGS-2 |
network_name_str |
Repositório Institucional da UFRGS |
repository_id_str |
|
spelling |
Nguyen, N. V.Sayan, S.Levin, IgorEhrstein, James R.Baumvol, Israel Jacob RabinDriemeier, Carlos EduardoKrug, CristianoWielunski, Leszek S.Hung, Puiyee Y.Diebold, Alain2020-01-22T04:10:23Z20050734-2101http://hdl.handle.net/10183/204762000530106We report the optical properties of unannealed hafnium–aluminate HfAlO films grown by atomic layer chemical vapor deposition ALCVD and correlate them with the aluminum contents in the films. Vacuum ultraviolet spectroscopic ellipsometry VUV-SE , high-resolution transmission electron microscopy HRTEM , channeling Rutherford backscattering spectrometry RBS , and resonant nuclear reaction analysis NRA were employed to characterize these films. In the analyses of ellipsometry data, a double Tauc–Lorentz dispersion produces a best fit to the experimental VUV-SE data. As a result, the determined complex pseudodielectric functions of the films clearly exhibit a dependency on the aluminum densities measured by RBS and NRA. We show that the optical fundamental band gap Eg shifts from 5.56±0.05 eV for HfO2 to 5.92±0.05 eV for HfAlO. The latter was grown by using an equal number of pulses of H2O/HfCl4 and H2O/TMA trimethylaluminum precursors in each deposition cycle for HfO2 and Al2O3, respectively. The shift of Eg to higher photon energies with increasing aluminum content indicates that intermixing of HfO2 and Al2O3 occurred during the ALCVD growth process. We found that Eg varies linearly with the mole fraction x of Al2O3 in the alloy HfO2 x Al2O3 1−x, but has a parabolic dependency with the aluminum density. We also observed a consistent decrease in the magnitudes of the real 1 and imaginary 2 part of of HfAlO films with respect to those of HfO2 as the Al density increased. The absence of the 5.7 eV peak in the spectrum, which was previously reported for polycrystalline HfO2 films, indicates that these films are amorphous as confirmed by their HRTEM images.application/pdfengJournal of Vacuum Science & Technology a : Vacuum, Surfaces and Films. New York. Vol. 23, no. 6 (Nov./Dec. 2005), p. 1706-1713Física da matéria condensadaEstado amorfoFilmes finos dieletricosIntervalo proibido de energiaConstantes óticasRetroespalhamento rutherfordMicroscopia eletrônica de transmissãoEspectros ultravioletaOptical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor depositionEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT000530106.pdf.txt000530106.pdf.txtExtracted Texttext/plain42224http://www.lume.ufrgs.br/bitstream/10183/204762/2/000530106.pdf.txtc9650e8c13ba00194a0ad6076a53ce51MD52ORIGINAL000530106.pdfTexto completo (inglês)application/pdf402614http://www.lume.ufrgs.br/bitstream/10183/204762/1/000530106.pdfe71cd387e5381ebc9553679288b3045fMD5110183/2047622023-06-15 03:28:14.108511oai:www.lume.ufrgs.br:10183/204762Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-06-15T06:28:14Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
title |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
spellingShingle |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition Nguyen, N. V. Física da matéria condensada Estado amorfo Filmes finos dieletricos Intervalo proibido de energia Constantes óticas Retroespalhamento rutherford Microscopia eletrônica de transmissão Espectros ultravioleta |
title_short |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
title_full |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
title_fullStr |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
title_full_unstemmed |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
title_sort |
Optical band gaps and composition dependence of hafnium–aluminate thin films grown by atomic layer chemical vapor deposition |
author |
Nguyen, N. V. |
author_facet |
Nguyen, N. V. Sayan, S. Levin, Igor Ehrstein, James R. Baumvol, Israel Jacob Rabin Driemeier, Carlos Eduardo Krug, Cristiano Wielunski, Leszek S. Hung, Puiyee Y. Diebold, Alain |
author_role |
author |
author2 |
Sayan, S. Levin, Igor Ehrstein, James R. Baumvol, Israel Jacob Rabin Driemeier, Carlos Eduardo Krug, Cristiano Wielunski, Leszek S. Hung, Puiyee Y. Diebold, Alain |
author2_role |
author author author author author author author author author |
dc.contributor.author.fl_str_mv |
Nguyen, N. V. Sayan, S. Levin, Igor Ehrstein, James R. Baumvol, Israel Jacob Rabin Driemeier, Carlos Eduardo Krug, Cristiano Wielunski, Leszek S. Hung, Puiyee Y. Diebold, Alain |
dc.subject.por.fl_str_mv |
Física da matéria condensada Estado amorfo Filmes finos dieletricos Intervalo proibido de energia Constantes óticas Retroespalhamento rutherford Microscopia eletrônica de transmissão Espectros ultravioleta |
topic |
Física da matéria condensada Estado amorfo Filmes finos dieletricos Intervalo proibido de energia Constantes óticas Retroespalhamento rutherford Microscopia eletrônica de transmissão Espectros ultravioleta |
description |
We report the optical properties of unannealed hafnium–aluminate HfAlO films grown by atomic layer chemical vapor deposition ALCVD and correlate them with the aluminum contents in the films. Vacuum ultraviolet spectroscopic ellipsometry VUV-SE , high-resolution transmission electron microscopy HRTEM , channeling Rutherford backscattering spectrometry RBS , and resonant nuclear reaction analysis NRA were employed to characterize these films. In the analyses of ellipsometry data, a double Tauc–Lorentz dispersion produces a best fit to the experimental VUV-SE data. As a result, the determined complex pseudodielectric functions of the films clearly exhibit a dependency on the aluminum densities measured by RBS and NRA. We show that the optical fundamental band gap Eg shifts from 5.56±0.05 eV for HfO2 to 5.92±0.05 eV for HfAlO. The latter was grown by using an equal number of pulses of H2O/HfCl4 and H2O/TMA trimethylaluminum precursors in each deposition cycle for HfO2 and Al2O3, respectively. The shift of Eg to higher photon energies with increasing aluminum content indicates that intermixing of HfO2 and Al2O3 occurred during the ALCVD growth process. We found that Eg varies linearly with the mole fraction x of Al2O3 in the alloy HfO2 x Al2O3 1−x, but has a parabolic dependency with the aluminum density. We also observed a consistent decrease in the magnitudes of the real 1 and imaginary 2 part of of HfAlO films with respect to those of HfO2 as the Al density increased. The absence of the 5.7 eV peak in the spectrum, which was previously reported for polycrystalline HfO2 films, indicates that these films are amorphous as confirmed by their HRTEM images. |
publishDate |
2005 |
dc.date.issued.fl_str_mv |
2005 |
dc.date.accessioned.fl_str_mv |
2020-01-22T04:10:23Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/204762 |
dc.identifier.issn.pt_BR.fl_str_mv |
0734-2101 |
dc.identifier.nrb.pt_BR.fl_str_mv |
000530106 |
identifier_str_mv |
0734-2101 000530106 |
url |
http://hdl.handle.net/10183/204762 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Journal of Vacuum Science & Technology a : Vacuum, Surfaces and Films. New York. Vol. 23, no. 6 (Nov./Dec. 2005), p. 1706-1713 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UFRGS instname:Universidade Federal do Rio Grande do Sul (UFRGS) instacron:UFRGS |
instname_str |
Universidade Federal do Rio Grande do Sul (UFRGS) |
instacron_str |
UFRGS |
institution |
UFRGS |
reponame_str |
Repositório Institucional da UFRGS |
collection |
Repositório Institucional da UFRGS |
bitstream.url.fl_str_mv |
http://www.lume.ufrgs.br/bitstream/10183/204762/2/000530106.pdf.txt http://www.lume.ufrgs.br/bitstream/10183/204762/1/000530106.pdf |
bitstream.checksum.fl_str_mv |
c9650e8c13ba00194a0ad6076a53ce51 e71cd387e5381ebc9553679288b3045f |
bitstream.checksumAlgorithm.fl_str_mv |
MD5 MD5 |
repository.name.fl_str_mv |
Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS) |
repository.mail.fl_str_mv |
|
_version_ |
1792790408020885504 |