P-Type Highly Doped Epitaxial Growth and Defect Control in 8-Inch 4H-SiC

doi:10.16553/j.cnki.issn1000-985x.2025.0224

Abstract

Abstract: Targeting the urgent demand for high-quality P-type highly doped epitaxial layers in high-voltage silicon carbide （SiC） power devices， this work systematically investigated the homoepitaxial growth technology of 8-inch （1 inch=2.54 cm） 4H-SiC based on trimethylaluminum （Al（CH₃）₃， TMA） precursor. By optimizing key parameters in the process of high-temperature chemical vapor deposition （CVD）， the controllable doping of aluminum （Al） in the epitaxial layer a doping concentration exceeding 1.00×10¹⁹ cm^-3 was successfully achieved on 8-inch and 4° off-axis 4H-SiC substrates， and the longitudinal doping uniformity in the epitaxial layer was good. The influence of doping concentration on defect morphology was analyzed by surface defect detection technology. The results show that when the Al doping concentration surpasses 1.35×10¹⁹ cm^-3， the lattice mismatch stress induces significant degradation of the surface morphology， and the degree of deterioration will increase with the increase of the Al doping concentration. Through further optimization of the growth conditions， the fatal defect density is successfully suppressed to 0.156 cm^-2 at a high doping concentration higher than 1.00×10¹⁹ cm^-3， so that the usable area ratio of 3 mm×3 mm chip area reaches 99.0%. This study provides an effective technical pathway for fabricating high-quality， large size P-type 4H-SiC epitaxial layers， laying a solid material for their industrial application in high-voltage power devices.

Key words: silicon carbide; P-type doping; 8-inch; epitaxial growth; usable area ratio; secondary ion mass spectrometry

CLC Number:

O484.1

JIANG Yitian, YE Zheng, CAI Zidong, WU Zihao, FANG Yutao, XIA Yun, CHEN Gang, HU Haolin, WAN Yuxi. P-Type Highly Doped Epitaxial Growth and Defect Control in 8-Inch 4H-SiC[J]. Journal of Synthetic Crystals, 2026, 55(3): 395-402.

Figures/Tables 6

Fig.1 SIMS measurement results of 10 μm thick epitaxial layer at center point coordinate （0， 0） and edge point coordinate （90， 0）

Fig.2 SIMS measurement results of P-type 4H-SiC epitaxial layer. （a） Al doping concentration as a function of TMA flow；（b） Al doping concentration as a function of C/Si ratio；（c） comparison of SIMS and Hg-CV measurement results at different Al doping concentrations

Fig.3 Surface morphology images of epitaxial layers at different Al doping concentrations. （a） 1.02×1019 cm-3；（b） 1.35×1019 cm-3；（c） 1.64×1019 cm-3；（d） 1.92×1019 cm-3

Fig.4 Surface morphology image of epitaxial layer without TMA doping. The solid square box indicates a magnified view of surface morphology； the red dashed circle box highlights silicon droplet defect

Fig.5 SIMS measurement results of Al doping concentration at different epitaxial growth rates. （a） 60 μm/h；（b） 25 μm/h

Fig.6 Surface measurement data of 30 μm thick P-type epitaxial layer. （a） Surface defect measurement data；（b） thickness measurement data；（c） surface flatness measurement data；（d） AFM image of central region

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