Deposition and characterisation of a diamond/Ti/diamond multilayer structure

In this work, a diamond/Ti/diamond multilayer structure has been fabricated by successively following thin-film CVD and PVD routes. It has been found that a combined pre-treatment of the silicon base substrate, via argon plasma etching for creating surface roughness and, thereafter, detonation nanod...

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Main Authors: Mallik, Awadesh Kumar, Lloret, Fernando, Gutierrez, Marina, Rouzbahani, Rozita, Pobedinskas, Paulius, Shih, Wen-Ching, Haenen, Ken
Other Authors: Temasek Laboratories @ NTU
Format: Article
Language:English
Published: 2024
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Online Access:https://hdl.handle.net/10356/173906
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spelling sg-ntu-dr.10356-1739062024-03-07T15:32:16Z Deposition and characterisation of a diamond/Ti/diamond multilayer structure Mallik, Awadesh Kumar Lloret, Fernando Gutierrez, Marina Rouzbahani, Rozita Pobedinskas, Paulius Shih, Wen-Ching Haenen, Ken Temasek Laboratories @ NTU Engineering Diamond Titanium In this work, a diamond/Ti/diamond multilayer structure has been fabricated by successively following thin-film CVD and PVD routes. It has been found that a combined pre-treatment of the silicon base substrate, via argon plasma etching for creating surface roughness and, thereafter, detonation nanodiamond (DND) seeding, helps in the nucleation and growth of well-adherent CVD diamond films with a well-defined Raman signal at 1332 cm−1, showing the crystalline nature of the film. Ti sputtering on such a CVD-grown diamond surface leads to an imprinted bead-like microstructure of the titanium film, generated from the underlying diamond layer. The cross-sectional thickness of the titanium layer can be found to vary by as much as 0.5 µm across the length of the surface, which was caused by a subsequent hydrogen plasma etching process step of the composite film conducted after Ti sputtering. The hydrogen plasma etching of the Ti–diamond composite film was found to be essential for smoothening the uneven as-grown texture of the films, which was developed due to the unequal growth of the microcrystalline diamond columns. Such hydrogen plasma surface treatment helped further the nucleation and growth of a nanocrystalline diamond film as the top layer, which was deposited following a similar CVD route to that used in depositing the bottom diamond layer, albeit with different process parameters. For the latter, a hydrogen gas diluted with PH3 precursor recipe produced smaller nanocrystalline diamond crystals for the top layer. The titanium layer in between the two diamond layers possesses a very-fine-grained microstructure. Transmission electron microscopy (TEM) results show evidence of intermixing between the titanium and diamond layers at their respective interfaces. The thin films in the composite multilayer follow the contour of the plasma-etched silicon substrate and are thus useful in producing continuous protective coatings on 3D objects—a requirement for many engineering applications. Published version This work was financially supported by the Methusalem NANO network and the Research Foundation—Flanders (FWO) via project G0D4920N. A.K.M. acknowledges FWO for his Postdoctoral Fellowship with grant No. 12X2919N. 2024-03-05T07:32:30Z 2024-03-05T07:32:30Z 2023 Journal Article Mallik, A. K., Lloret, F., Gutierrez, M., Rouzbahani, R., Pobedinskas, P., Shih, W. & Haenen, K. (2023). Deposition and characterisation of a diamond/Ti/diamond multilayer structure. Coatings, 13(11), 13111914-. https://dx.doi.org/10.3390/coatings13111914 2079-6412 https://hdl.handle.net/10356/173906 10.3390/coatings13111914 2-s2.0-85177820745 11 13 13111914 en Coatings © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering
Diamond
Titanium
spellingShingle Engineering
Diamond
Titanium
Mallik, Awadesh Kumar
Lloret, Fernando
Gutierrez, Marina
Rouzbahani, Rozita
Pobedinskas, Paulius
Shih, Wen-Ching
Haenen, Ken
Deposition and characterisation of a diamond/Ti/diamond multilayer structure
description In this work, a diamond/Ti/diamond multilayer structure has been fabricated by successively following thin-film CVD and PVD routes. It has been found that a combined pre-treatment of the silicon base substrate, via argon plasma etching for creating surface roughness and, thereafter, detonation nanodiamond (DND) seeding, helps in the nucleation and growth of well-adherent CVD diamond films with a well-defined Raman signal at 1332 cm−1, showing the crystalline nature of the film. Ti sputtering on such a CVD-grown diamond surface leads to an imprinted bead-like microstructure of the titanium film, generated from the underlying diamond layer. The cross-sectional thickness of the titanium layer can be found to vary by as much as 0.5 µm across the length of the surface, which was caused by a subsequent hydrogen plasma etching process step of the composite film conducted after Ti sputtering. The hydrogen plasma etching of the Ti–diamond composite film was found to be essential for smoothening the uneven as-grown texture of the films, which was developed due to the unequal growth of the microcrystalline diamond columns. Such hydrogen plasma surface treatment helped further the nucleation and growth of a nanocrystalline diamond film as the top layer, which was deposited following a similar CVD route to that used in depositing the bottom diamond layer, albeit with different process parameters. For the latter, a hydrogen gas diluted with PH3 precursor recipe produced smaller nanocrystalline diamond crystals for the top layer. The titanium layer in between the two diamond layers possesses a very-fine-grained microstructure. Transmission electron microscopy (TEM) results show evidence of intermixing between the titanium and diamond layers at their respective interfaces. The thin films in the composite multilayer follow the contour of the plasma-etched silicon substrate and are thus useful in producing continuous protective coatings on 3D objects—a requirement for many engineering applications.
author2 Temasek Laboratories @ NTU
author_facet Temasek Laboratories @ NTU
Mallik, Awadesh Kumar
Lloret, Fernando
Gutierrez, Marina
Rouzbahani, Rozita
Pobedinskas, Paulius
Shih, Wen-Ching
Haenen, Ken
format Article
author Mallik, Awadesh Kumar
Lloret, Fernando
Gutierrez, Marina
Rouzbahani, Rozita
Pobedinskas, Paulius
Shih, Wen-Ching
Haenen, Ken
author_sort Mallik, Awadesh Kumar
title Deposition and characterisation of a diamond/Ti/diamond multilayer structure
title_short Deposition and characterisation of a diamond/Ti/diamond multilayer structure
title_full Deposition and characterisation of a diamond/Ti/diamond multilayer structure
title_fullStr Deposition and characterisation of a diamond/Ti/diamond multilayer structure
title_full_unstemmed Deposition and characterisation of a diamond/Ti/diamond multilayer structure
title_sort deposition and characterisation of a diamond/ti/diamond multilayer structure
publishDate 2024
url https://hdl.handle.net/10356/173906
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