Growth Process of GaN Crystals by Flux-Excess-Assisted Liquid Phase Epitaxy

doi:10.16553/j.cnki.issn1000-985x.2025.0229

Abstract

Abstract: This study systematically investigated the effects of surface morphology， yield and quality of GaN crystals grown for different durations by adopting the Na flux liquid phase epitaxy method. Combined with the change of material in the crucible and calculation of N ion concentration during the growth process， the growth process of GaN crystal by flux-excess-assisted liquid phase epitaxy was elucidated. The results indicate that with the extension of growth time， the surface morphology of the crystals gradually evolves from the initial small-sized ridge-like to the pyramids shape， and eventually develops into large-sized ridge-like morphologies. The epitaxial thickness of the crystals increases with the extension of growth time， and the growth thickness is approximately 1 500 μm when the growth time is 100 h. Meanwhile， the crystal yield is significantly improved， exhibiting an approximately linear correlation with the growth time. When the growth time is 100 h， the single crystals yield， polycrystals yield and total yield of GaN are about 65.5%， 18.5% and 84.0%， respectively. In the initial growth stage， the full width at half maximum （FWHM） of the X-ray rocking curve （XRC） for the （0002） plane is less than 270″， and it gradually increases with the extension of growth time. The calculation results of the residual materials in the melt during growth process show that the mass of residual metallic Ga decreases linearly with growth time， whereas the mass of residual metallic Na increases slightly in the initial growth stage and then stabilizes in the later stage. Numerical calculation results reveal that the N ion concentration in the melt shows an increasing trend with the extension of growth time. This work provides important experimental and theoretical basis for regulating the morphology， improving the yield and optimizing the growth process of GaN crystals.

Key words: GaN; Na flux method; liquid phase epitaxy; flux-excess; growth process

CLC Number:

O782

YANG Chen, HUANG Gemeng, PAN Ronglin, MA Ming, XIA Song, FAN Shiji, LI Zhenrong. Growth Process of GaN Crystals by Flux-Excess-Assisted Liquid Phase Epitaxy[J]. Journal of Synthetic Crystals, 2026, 55(3): 423-430.

Figures/Tables 10

Fig.1 XRD patterns of GaN crystal surfaces grown for different durations

Fig.2 SEM images of GaN crystal surfaces grown for different durations

Fig.3 Cross-sectional morphologies of GaN crystals grown for different durations

Fig.4 Yield of GaN crystals grown for different durations

Fig.5 Variation curve of XRC FWHM on GaN crystal surfaces grown for different durations

Fig.6 Variation curve of flux Na mass in melt with growth time

Fig.7 Variation curve of Ga molar fraction in melt with growth time

Fig.8 N ion concentration distribution in melt at end of GaN crystal growth

Fig.9 N ion concentration distribution at growth interface

Tabel 1 Maximum value （CN，max） and minimum value （CN，min） of CN at growth interfaces grown for different durations

Parameter	6 h	12 h	25 h	50 h	75 h	100 h
C_N，min/（10²⁰ atoms∙cm^-3）	1.114 072	1.117 922	1.121 926	1.132 350	1.147 992	1.162 402
C_N_，_max/（10²⁰ atoms∙cm^-3）	1.120 388	1.124 275	1.128 259	1.138 709	1.154 464	1.168 979
ΔC_N/（10²⁰ atoms∙cm^-3）	0.006 316	0.006 353	0.006 330	0.006 359	0.006 472	0.006 577

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