Publication
Title
The effect of microstructure and film composition on the mechanical properties of linear antenna CVD diamond thin films
Author
Abstract
This study reports the impact of film microstructure and composition on the Young's modulus and residual stress in nanocrystalline diamond (NCD) thin films (approximate to 250 nm thick) grown on silicon substrates using a linear antenna microwave plasma-enhanced chemical vapor deposition (CVD) system. Combining laser acoustic wave spectroscopy to determine the elastic properties with simple wafer curvature measurements, a straightforward method to determine the intrinsic stress in NCD films is presented. Two deposition parameters are varied: (1) the substrate temperature from 400 degrees C to 900 degrees C, and (2) the [P]/[C] ratio from 0 ppm to 8090 ppm in the H2/CH4/CO2/PH3 diamond CVD plasma. The introduction of PH3 induces a transition in the morphology of the diamond film, shifting from NCD with larger grains to ultra-NCD with a smaller grain size, concurrently resulting in a decrease in Young's modulus. Results show that the highest Young's modulus of (1130 +/- 50) GPa for the undoped NCD deposited at 800 degrees C is comparable to single crystal diamond, indicating that NCD with excellent mechanical properties is achievable with our process for thin diamond films. Based on the film stress results, we propose the origins of tensile intrinsic stress in the diamond films. In NCD, the tensile intrinsic stress is attributed to larger grain size, while in ultra-NCD films the tensile intrinsic stress is due to grain boundaries and impurities.
Language
English
Source (journal)
Acta materialia. - Oxford
Publication
Oxford : 2024
ISSN
1359-6454
DOI
10.1016/J.ACTAMAT.2023.119548
Volume/pages
264 (2024) , p. 1-8
Article Reference
119548
ISI
001126632800001
Full text (Publisher's DOI)
Full text (open access)
The author-created version that incorporates referee comments and is the accepted for publication version Available from 25.05.2024
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identifier
Creation 09.01.2024
Last edited 18.01.2024
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