Fabrication of high aspect ratio TiO2 and Al2O3 nanogratings by atomic layer deposition

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Abstract

The authors report on the fabrication of TiO2 and Al2O3 nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching followed by ALD of TiO2 or Al2O3. Then, the template was etched away using SF6 in an
inductively coupled plasma tool, which resulted in the formation of isolated ALD coatings, thereby achieving high aspect ratio grating structures. SF6 plasma removes silicon selectively without any observable influence on TiO2 or Al2O3, thus revealing high selectivity throughout the fabrication. Scanning electron microscopy was used to analyze every fabrication step. Due to nonreleased stress in the ALD coatings, the top parts of the gratings were observed to bend inward as the Sitemplate was removed, thus resulting in a gradual change in the pitch value of the structures. The pitch on top of the gratings is 400 nm, and it gradually reduces to 200 nm at the bottom. The form of the bending can be reshaped by Arþ ion beam etching. The chemical purity of the ALD grown materials was analyzed by x-ray photoelectron spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures.
Original languageEnglish
Article number031605
JournalJournal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films
Volume34
Issue number3
Number of pages6
ISSN0734-2101
DOIs
Publication statusPublished - 2016

Bibliographical note

© 2016 American Vacuum Society

Cite this

@article{b1590e44cb204f82b13ed17be23e77ed,
title = "Fabrication of high aspect ratio TiO2 and Al2O3 nanogratings by atomic layer deposition",
abstract = "The authors report on the fabrication of TiO2 and Al2O3 nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching followed by ALD of TiO2 or Al2O3. Then, the template was etched away using SF6 in an inductively coupled plasma tool, which resulted in the formation of isolated ALD coatings, thereby achieving high aspect ratio grating structures. SF6 plasma removes silicon selectively without any observable influence on TiO2 or Al2O3, thus revealing high selectivity throughout the fabrication. Scanning electron microscopy was used to analyze every fabrication step. Due to nonreleased stress in the ALD coatings, the top parts of the gratings were observed to bend inward as the Sitemplate was removed, thus resulting in a gradual change in the pitch value of the structures. The pitch on top of the gratings is 400 nm, and it gradually reduces to 200 nm at the bottom. The form of the bending can be reshaped by Ar{\th} ion beam etching. The chemical purity of the ALD grown materials was analyzed by x-ray photoelectron spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures.",
author = "Evgeniy Shkondin and Osamu Takayama and Jonas Michael-Lindhard and Larsen, {Pernille Voss} and Mar, {Mikkel Dysseholm} and Flemming Jensen and Andrei Lavrinenko",
note = "{\circledC} 2016 American Vacuum Society",
year = "2016",
doi = "10.1116/1.4947586",
language = "English",
volume = "34",
journal = "Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films",
issn = "0734-2101",
publisher = "American Vacuum Society",
number = "3",

}

TY - JOUR

T1 - Fabrication of high aspect ratio TiO2 and Al2O3 nanogratings by atomic layer deposition

AU - Shkondin, Evgeniy

AU - Takayama, Osamu

AU - Michael-Lindhard, Jonas

AU - Larsen, Pernille Voss

AU - Mar, Mikkel Dysseholm

AU - Jensen, Flemming

AU - Lavrinenko, Andrei

N1 - © 2016 American Vacuum Society

PY - 2016

Y1 - 2016

N2 - The authors report on the fabrication of TiO2 and Al2O3 nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching followed by ALD of TiO2 or Al2O3. Then, the template was etched away using SF6 in an inductively coupled plasma tool, which resulted in the formation of isolated ALD coatings, thereby achieving high aspect ratio grating structures. SF6 plasma removes silicon selectively without any observable influence on TiO2 or Al2O3, thus revealing high selectivity throughout the fabrication. Scanning electron microscopy was used to analyze every fabrication step. Due to nonreleased stress in the ALD coatings, the top parts of the gratings were observed to bend inward as the Sitemplate was removed, thus resulting in a gradual change in the pitch value of the structures. The pitch on top of the gratings is 400 nm, and it gradually reduces to 200 nm at the bottom. The form of the bending can be reshaped by Arþ ion beam etching. The chemical purity of the ALD grown materials was analyzed by x-ray photoelectron spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures.

AB - The authors report on the fabrication of TiO2 and Al2O3 nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching followed by ALD of TiO2 or Al2O3. Then, the template was etched away using SF6 in an inductively coupled plasma tool, which resulted in the formation of isolated ALD coatings, thereby achieving high aspect ratio grating structures. SF6 plasma removes silicon selectively without any observable influence on TiO2 or Al2O3, thus revealing high selectivity throughout the fabrication. Scanning electron microscopy was used to analyze every fabrication step. Due to nonreleased stress in the ALD coatings, the top parts of the gratings were observed to bend inward as the Sitemplate was removed, thus resulting in a gradual change in the pitch value of the structures. The pitch on top of the gratings is 400 nm, and it gradually reduces to 200 nm at the bottom. The form of the bending can be reshaped by Arþ ion beam etching. The chemical purity of the ALD grown materials was analyzed by x-ray photoelectron spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures.

U2 - 10.1116/1.4947586

DO - 10.1116/1.4947586

M3 - Journal article

VL - 34

JO - Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films

JF - Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films

SN - 0734-2101

IS - 3

M1 - 031605

ER -