Effect of surface roughness on the nucleation of diamond on a 4H-SiC substrate
Diamond has the highest thermal conductivity among all materials and can be applied to overcome the heat dissipation problem in radio frequency devices based on the heterojunction of gallium nitride (GaN) and 4H silicon carbide (4H-SiC). However, growing high-quality diamond films on 4H-SiC substrat...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Taylor & Francis Group
2025-12-01
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| Series: | Functional Diamond |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1080/26941112.2025.2529858 |
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| Summary: | Diamond has the highest thermal conductivity among all materials and can be applied to overcome the heat dissipation problem in radio frequency devices based on the heterojunction of gallium nitride (GaN) and 4H silicon carbide (4H-SiC). However, growing high-quality diamond films on 4H-SiC substrates is quite difficult due to the very low nucleation density of diamond on their surfaces. In this study, the thermodynamic models of diamond nucleation on 4H-SiC substrates were carefully analyzed to investigate the effect of different surface states on diamond nucleation. The results indicated that although a 4H-SiC substrate with a smooth surface can significantly reduce the formation energy of diamond nucleation, it remains challenging for diamond to nucleate on the substrate. Fortunately, increasing the surface roughness can further decrease the formation energy of diamond nucleation and significantly increase the nucleation density on the 4H-SiC substrate, enabling the formation of a continuous high-quality film. Additionally, the rough surface of 4H-SiC substrates lapped by abrasives with small particle size contained numerous nanoscale defects and dense scratches, which serve as active sites for diamond nucleation. The smaller the particle size of the abrasives, the higher the nucleation density of diamond, which is also beneficial for the epitaxial growth of diamond on 4H-SiC substrates. Finally, crack-free diamond films on 4H-SiC substrates were successfully fabricated using an MPCVD system, and their properties were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD), respectively. |
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| ISSN: | 2694-1120 |