Growth and Properties of 4-Inch Fe Doped (010) β -Gallium Oxide Using Vertical Bridgman Method

doi:10.16553/j.cnki.issn1000-985x.2025.0159

Abstract

Abstract: In this study， a self-built vertical Bridgman （VB） system was utilized to grow large-size， high-quality Fe-doped β-Ga₂O₃ single crystals. Through iterative thermal field optimization via simulation， slightly convex solid-liquid interface and appropriate temperature gradient were achieved. The as-grown crystal was further processed into a high-quality 4-inch （010） oriented semi-insulating substrate. Comprehensive evaluations of crystallinity， surface morphology， and electrical properties were carried out. The substrate exhibits no macroscopic defects such as cracks. Multi-point X-ray rocking curve measurements show full width at half maximum （FWHM） values all below 50″， indicating superior crystalline quality. Surface topography tests reveal a maximum roughness of 0.074 nm， local thickness variation （LTV） below 3.4 μm， total thickness variation （TTV） of 4.157 μm， warp of 5.886 μm， and bow of 1.103 μm， demonstrating excellent processing quality. Moreover， the substrate displays high average resistivity of approximately 7.9×10¹⁰ Ω·cm with an in-plane inhomogeneity of about 7.77%， underscoring the effectiveness of VB method in achieving uniform doping distribution and its potential for radio frequency （RF） and microwave device applications.

Key words: Ga₂O₃; wide-bandgap semiconductor; crystal growth; vertical Bridgman; single crystal substrate; doping

CLC Number:

O782⁺.5

LI Ming, YE Haohan, WANG Cheng, SHEN Dianyu, WANG Yunxia, WANG Jiajun, XIA Ning, ZHANG Hui, YANG Deren. Growth and Properties of 4-Inch Fe Doped (010) β -Gallium Oxide Using Vertical Bridgman Method[J]. Journal of Synthetic Crystals, 2026, 55(1): 52-57.

Figures/Tables 6

Table 1 Material properties of β-Ga2O3 melts and crystals

Property	Melt	Crystal
Density，ρ/（kg·m^-3）	6 217.35-0.65T	5 974.5-0.0 815T
Specific heat，c_p/（J∙kg^-1∙K^-1）	850	700
Thermal conductivity， λ/（W∙m^-1∙K^-1）	4.3	32 800×（1/T）^1.27
Emissivity， ε	0.5	0.3
Melting temperature， T_m/K	—	2 093
Latent thermal， ΔH/（kJ·kg^-1）	533.5	—
Viscosity， μ/（Pa∙s）	0.05	—

Fig.1 Schematic section of VB furnace （a）， and simulated temperature gradient and solid-liquid interface of crystal growth using VB method （b）

Fig.2 4-inch Fe∶β-Ga2O3 （010） single crystal substrate （a） and polarized photo （b）

Fig.3 Five point positions （a） and high-resolution XRD curve test results （b） of 4-inch Fe∶β-Ga2O3 （010） single crystal substrate

Fig.4 Five-point surface roughness （a） and 3D topography diagram （b） from local thickness variation of 4-inch Fe∶β-Ga2O3 （010） single crystal substrate

Fig.5 Electrical resistance distribution of 4-inch Fe∶β-Ga2O3 （010） single crystal substrate

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