Novel characterization method for the nitrogen doping concentration in heavily nitrogen-doped 4H-SiC crystals by Raman scattering microscopy

Yokomoto, Kaito; Shioura, Kentaro; Yabu, Masahiro; Nakano, Masataka; Ohtani, Noboru

doi:10.35848/1347-4065/ab8758

Cited by 12 publications

(3 citation statements)

References 28 publications

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“…The nitrogen doping variation across the (0001) facet was imaged by Raman scattering microscopy through the changes in the peak frequency and integrated intensity of the longitudinal optical phonon-plasmon coupled (LOPC) mode at ∼965 cm −1 . [20][21][22] Raman scattering microscopy imaging was conducted in the quasi-backscattering geometry at room temperature using a confocal optical microscope with a diode-pumped Nd:YVO 4 laser at 532 nm used for excitation. The LOPC mode shows distinct changes in the peak position and profile when the carrier concentration in 4H-SiC crystals changes, and thus, the change in the peak position 20,21) and integrated intensity 22) can be utilized to detect the nitrogen doping variation across the (0001) facet.…”

Section: Experimental Methodsmentioning

confidence: 99%

Enhanced nitrogen incorporation in the 〈112̄0〉 directions on the (0001̄) facet of 4H-SiC crystals

Hashiguchi¹,

Ota²,

Asano³

et al. 2022

Jpn. J. Appl. Phys.

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Enhanced nitrogen doping in the <11−20> directions on the (000−1) facet of 4H-SiC crystals grown by the physical vapor transport (PVT) growth method was investigated using Raman scattering microscopy and atomic force microscopy (AFM). The enhanced nitrogen doping showed either single or double peak structure of nitrogen incorporation in the azimuthal direction around <11−20>. AFM observations revealed that these two characteristic doping structures stemmed from different propagation morphologies of spiral steps on the (000−1) facet. It was also unveiled that the change in the step-flow direction was always associated with the change of the terrace-width ratio on the facet, and that the interplay between these two parameters determined the nitrogen incorporation on the (000−1) facet. On the basis of these experimental results, the mechanism of the azimuthal dependence of nitrogen incorporation on the (000−1) facet during PVT growth of 4H-SiC crystals is discussed.

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Section: Experimental Methodsmentioning

confidence: 99%

Enhanced nitrogen incorporation in the 〈112̄0〉 directions on the (0001̄) facet of 4H-SiC crystals

Hashiguchi¹,

Ota²,

Asano³

et al. 2022

Jpn. J. Appl. Phys.

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“…In order to detect the nitrogen content more conveniently in 4H-SiC, Yokomoto et al applied Raman measurements auxiliary to the compositive pattern to monitor a small change of the Nc across the (0001) facet of SiC crystal, and the suggested method showed a much higher sensitivity to the N doping transformation compared with traditional methods [120]. At present, n-type 4H-SiC had achieved industrial application, while the popular size of SiC in the market was mainly 4 inches and 6 inches, but 8 inches of products were still in the process.…”

Section: Doping Of 4h-sicmentioning

confidence: 99%

Advances and challenges in 4H silicon carbide: defects and impurities

Yang,

Tong,

et al. 2024

Phys. Scr.

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Under the impetus of global carbon peak and carbon neutrality goals, a new generation of semiconductor material is urgently needed in various aspects of power electronic systems. In comparison to traditional semiconductor materials like single-crystal silicon, the outstanding characteristics of 4H silicon carbide (4H-SiC) have gradually positioned it as a crucial semiconductor material for emerging power semiconductor applications. Given the significance of impurities and defects in the semiconductor, comprehensive and in-depth understanding of impurities and defects about 4H-SiC plays a crucial guiding role. This paper, building upon a brief overview of the current state of 4H-SiC research, summarizes the experimental and theoretical advancements in the study of defects and impurities about 4H-SiC in recent years. Besides, we also systematically review the categories of defects in 4H-SiC, introduce methods for characterizing and identifying defects in 4H-SiC, and thoroughly discuss potential doping technologies in 4H-SiC. Challenges faced in the research of defects and impurities are ﬁnally outlined.

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“…A suitable optical spectroscopic method for screening N-doped SiC wafers in terms of carrier density and mobility may be offered by Raman spectroscopy. 12,13 Raman spectra of the longitudinal-optical (LO) phonon region in polar semiconductors like SiC can yield information about charge carrier density and mobility of doped samples. The underlying physical effect is that the LO phonon couples to the free charge carriers introduced by doping giving rise to longitudinal optical phonon coupled (LOPC) modes.…”

Section: Introductionmentioning

confidence: 99%

Validation of Raman spectroscopy as a tool for mapping transport parameters in inhomogeneous N‐doped 4H‐SiC

Hergert

Elm

Klar

2023

J Raman Spectroscopy

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We assess Raman spectroscopy as a tool for fast and non‐invasive mapping of charge carrier density and carrier mobility in inhomogeneously doped 4H‐SiC. For this purpose, we compare values of these transport parameters obtained by magneto‐transport and Raman measurements of N‐doped 4H‐SiC. The comparison is not straightforward. The effective charge density and mobility, which are obtained from resistivity and Hall measurements by employing the commonly used effective one‐band model, deviate from the values extracted by applying the established line‐shape models for describing the longitudinal optical phonon coupled (LOPC) modes in the Raman spectra. Differentiating between free and localized carriers in the framework of a three‐band transport model confirms that only the free charge carriers in the conduction band of N‐doped 4H‐SiC contribute to the LOPC Raman signal and their density agrees well with that obtained by the line shape analysis. The agreement of the mobility values is good keeping in mind that different frequencies of the applied electric fields are used in the two approaches, i.e., dc‐transport measurements at 0 Hz and ac‐fields of the exciting laser at about 500 THz. Moreover, the excitation of electrons into the conduction band by the laser, which is inherent to the Raman experiment, causes differences in the temperature dependence of the carrier density compared with the electrical transport data.

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Novel characterization method for the nitrogen doping concentration in heavily nitrogen-doped 4H-SiC crystals by Raman scattering microscopy

Cited by 12 publications

References 28 publications

Enhanced nitrogen incorporation in the 〈112̄0〉 directions on the (0001̄) facet of 4H-SiC crystals

Enhanced nitrogen incorporation in the 〈112̄0〉 directions on the (0001̄) facet of 4H-SiC crystals

Advances and challenges in 4H silicon carbide: defects and impurities

Validation of Raman spectroscopy as a tool for mapping transport parameters in inhomogeneous N‐doped 4H‐SiC

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