Process optimization for homoepitaxial growth of thick 4H-SiC films via hydrogen chloride chemical vapor deposition

Liu, X.F.; Yan, Guangwu; Liu, Bobo; Shen, Zhongshan; Wen, Zheng; Chen, J.; Zhao, Wei; Wang, L.; Feng, Zhaochi; Sun, Guang–Zhen; Zeng, Yiping

doi:10.1016/j.jcrysgro.2018.09.030

Cited by 12 publications

(6 citation statements)

References 20 publications

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“…Therefore, a small C/Si ratio was selected. In the homoepitaxial growth of 4H-SiC, large steps tend to format in the environment with small C/Si ratio [19][20][21]. The growth conditions were 40 Torr, C/Si = 1, and 30 min respectively.…”

Section: Methodsmentioning

confidence: 99%

Surface flattening of 4H-SiC (0001) epitaxial wafers by high temperature oxidation

Zhao

Wang

Yan

et al. 2022

Semicond. Sci. Technol.

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Due to the special "Step-Controlled Epitaxy" mode of 4H-SiC, it is easy to generate step bunching on the surface. Although the flatness of epitaxial wafers has been greatly improved with the advancement of epitaxy technology, there are still localized steps on the surface of some certain wafers. The presence of localized steps can affect the performance of the subsequently fabricated devices. Therefore, minimizing or even eliminating the local steps of the epitaxial surface to obtain an atomically smooth surface is very important. Here, we utilize a high-temperature oxidation process to reduce the size of the giant steps and obtain a flatter epitaxial surface. We found that oxidation parameters such as temperature, pressure, and time play an important role in the surface planarization, and the degree of planarization can be further improved by multiple oxidation processes. In addition, although the oxidation rate under low pressure is lower than that under atmospheric pressure, a smoother epitaxial surface can be obtained. Our results demonstrate the possibility of obtaining atomically smooth surfaces through a high-temperature oxidation process.

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Section: Methodsmentioning

confidence: 99%

Surface flattening of 4H-SiC (0001) epitaxial wafers by high temperature oxidation

Zhao

Wang

Yan

et al. 2022

Semicond. Sci. Technol.

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“…In recent years, 4H-SiC chemical vapor deposition (CVD) technology has rapidly developed with the breakthrough of key technologies such as "step flow epitaxy" [11,12] and "chlorine-based high-speed epitaxy" [13,14], resulting in gradual improvements in the crystal quality of SiC epitaxial layers. However, the crystal quality still needs to be improved for many high-voltage and high-power SiC power electronic devices.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, a large portion of these TDs exhibit characteristics similar to comet defect or other defects in the triangular region of TDs [19]. The projection length L of these surface morphological defects like TDs along the [11][12][13][14][15][16][17][18][19][20] direction satisfies the equation:…”

Section: Introductionmentioning

confidence: 99%

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Multiple-Layer Triangular Defects in 4H-SiC Homoepitaxial Films Grown by Chemical Vapor Deposition

et al. 2023

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In this study, a special triangular defect (TD) was identified on 4H-SiC epitaxial wafers. The morphology and composition characteristics of these special TDs were revealed by Raman, atomic force microscope (AFM), and scanning electron microscope (SEM). Compared to ordinary triangular defects, this defect protruded from the epitaxial layer and exhibited a laminated shape. The study also discussed the effects of several factors, such as C/Si ratio and growth time, on the triangular defects. Through analysis of these results, we developed methods to suppress the triangular defects. This research provides new insights into the morphology, structure, and composition of this serious destructive defect and is helpful for improving the performance of SiC epitaxial wafers.

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“…Specifically, the study analyzes the effects of the carbon-silicon ratio, growth temperature, and N 2 flow ratio on the growth quality. Previous studies have primarily focused on investigating the effects of a high C/Si ratio (≥1) or high growth temperature (≥1600 • C) on the homoepitaxial growth of 4H-SiC [18][19][20]. Optimizing the surface morphology of the epitaxial layer can be achieved by subjecting a small-sized 4H-SiC substrate to high temperatures above 1600 • C [21].…”

Section: Introductionmentioning

confidence: 99%

The Optimizing Effect of Nitrogen Flow Ratio on the Homoepitaxial Growth of 4H-SiC Layers

et al. 2023

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In this study, a 4H-SiC homoepitaxial layer was grown on a 150 mm 4° off-axis substrate using a horizontal hot-wall CVD reactor. The research aimed to investigate the impact of varying the C/Si ratio and temperature while also changing the N2 flow rate and N2 flow ratio on the growth rate (thickness), doping, surface roughness, and uniformity of the large-size 4H-SiC epitaxial layer. The results indicate that the growth rate and thickness uniformity of the film increases with an increase in the C/Si ratio. Additionally, adjusting the N2 flow rate in a timely manner based on the change in the C/Si ratio is crucial to achieving the best epitaxial layer doping concentration and uniformity. The study found that, as the temperature increases, the film thickness and thickness uniformity also increase. The maximum thickness recorded was 6.2 μm, while the minimum thickness uniformity was 1.44% at 1570 °C. Additionally, the surface roughness reached its lowest point at 0.81 nm at 1570 °C. To compensate for the difference in thickness and doping concentration caused by temperature distribution and uneven airflow, the N2 flow ratio was altered. In particular, at a growth temperature of 1570 °C, a N2 flow ratio of 1.78 can improve the uniformity of doping by 4.12%.

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Process optimization for homoepitaxial growth of thick 4H-SiC films via hydrogen chloride chemical vapor deposition

Cited by 12 publications

References 20 publications

Surface flattening of 4H-SiC (0001) epitaxial wafers by high temperature oxidation

Surface flattening of 4H-SiC (0001) epitaxial wafers by high temperature oxidation

Multiple-Layer Triangular Defects in 4H-SiC Homoepitaxial Films Grown by Chemical Vapor Deposition

The Optimizing Effect of Nitrogen Flow Ratio on the Homoepitaxial Growth of 4H-SiC Layers

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