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Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers

In this work, 4H-SiC epilayers are performed on 4° off-axis substrates under low pressure condition by horizontal hot wall chemical vapor deposition (HWCVD) with a standard chemistry of silane-propane-hydrogen, which focuses on the effects of growth pressure on morphology, basal plane dislocations (...

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Autores principales: Hu, Jichao, Jia, Renxu, Xin, Bin, Peng, Bo, Wang, Yuehu, Zhang, Yuming
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457113/
https://www.ncbi.nlm.nih.gov/pubmed/28773864
http://dx.doi.org/10.3390/ma9090743
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author Hu, Jichao
Jia, Renxu
Xin, Bin
Peng, Bo
Wang, Yuehu
Zhang, Yuming
author_facet Hu, Jichao
Jia, Renxu
Xin, Bin
Peng, Bo
Wang, Yuehu
Zhang, Yuming
author_sort Hu, Jichao
collection PubMed
description In this work, 4H-SiC epilayers are performed on 4° off-axis substrates under low pressure condition by horizontal hot wall chemical vapor deposition (HWCVD) with a standard chemistry of silane-propane-hydrogen, which focuses on the effects of growth pressure on morphology, basal plane dislocations (BPDs) and crystalline quality. It is found that morphological defects reduce with the decreasing of growth pressure, since the surface diffusion length of absorbed adatoms increases under low growth pressure, which suppresses the nucleation of adatoms on terraces and the formation of morphological defects. However, as the surface diffusion length increases under low growth pressure, the difference of growth velocity at steps is enhanced, which leads to the extension of the steps’ width and the formation of step-bunching. Besides variation of surface diffusion length, the phenomenon described above can be correlated with different dominate modes for the minimization of surface energy at varied growth pressure. Because of the contrary influence of increased C/Si ratio and enhanced step-flow growth on the propagation of BPDs, the dislocation densities of BPDs and threading edge dislocations (TEDs) in epilayers grown at varied pressures remain basically unchanged. The crystalline quality is almost independent of growth pressure based on high resolution X-ray diffraction (HRXRD) measurements.
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spelling pubmed-54571132017-07-28 Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers Hu, Jichao Jia, Renxu Xin, Bin Peng, Bo Wang, Yuehu Zhang, Yuming Materials (Basel) Article In this work, 4H-SiC epilayers are performed on 4° off-axis substrates under low pressure condition by horizontal hot wall chemical vapor deposition (HWCVD) with a standard chemistry of silane-propane-hydrogen, which focuses on the effects of growth pressure on morphology, basal plane dislocations (BPDs) and crystalline quality. It is found that morphological defects reduce with the decreasing of growth pressure, since the surface diffusion length of absorbed adatoms increases under low growth pressure, which suppresses the nucleation of adatoms on terraces and the formation of morphological defects. However, as the surface diffusion length increases under low growth pressure, the difference of growth velocity at steps is enhanced, which leads to the extension of the steps’ width and the formation of step-bunching. Besides variation of surface diffusion length, the phenomenon described above can be correlated with different dominate modes for the minimization of surface energy at varied growth pressure. Because of the contrary influence of increased C/Si ratio and enhanced step-flow growth on the propagation of BPDs, the dislocation densities of BPDs and threading edge dislocations (TEDs) in epilayers grown at varied pressures remain basically unchanged. The crystalline quality is almost independent of growth pressure based on high resolution X-ray diffraction (HRXRD) measurements. MDPI 2016-08-31 /pmc/articles/PMC5457113/ /pubmed/28773864 http://dx.doi.org/10.3390/ma9090743 Text en © 2016 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 (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Hu, Jichao
Jia, Renxu
Xin, Bin
Peng, Bo
Wang, Yuehu
Zhang, Yuming
Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers
title Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers
title_full Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers
title_fullStr Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers
title_full_unstemmed Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers
title_short Effect of Low Pressure on Surface Roughness and Morphological Defects of 4H-SiC Epitaxial Layers
title_sort effect of low pressure on surface roughness and morphological defects of 4h-sic epitaxial layers
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457113/
https://www.ncbi.nlm.nih.gov/pubmed/28773864
http://dx.doi.org/10.3390/ma9090743
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