Growth of GaN Single Crystals on Sapphire Patterned-porous Thin Film Composite Substrate

doi:10.15541/jim20250481

Abstract

Abstract:

Due to the large lattice mismatch and thermal mismatch between gallium nitride (GaN) and hetero-substrates, high-density mismatch dislocations are introduced in the GaN epitaxial layer, thereby reducing the performance and lifetime of the devices. The most fundamental solution to this problem is to grow GaN on GaN homo-substrate. In this study, GaN films were first grown on a patterned sapphire substrate using metal-organic chemical vapor deposition method. Then, the GaN films were wet-etched to fabricate a sapphire patterned-porous film composite substrate. Subsequently, GaN single crystals were grown on this substrate, and GaN bulk single crystals were obtained by self-peeling. The feasibility of this process was experimentally verified. The test results of X-ray diffraction (XRD), Raman spectroscopy, photoluminescence (PL) spectroscopy, and cathodoluminescence (CL) spectroscopy confirm that the crystallinity and quality of grown GaN single crystals were improved. At the same time, the growth mechanism of GaN single crystals on the sapphire patterned-porous thin film composite substrate is expounded, providing a new idea for improving the quality of self-stripping GaN single crystals.

Key words: sapphire pattern, porous, composite substrate, GaN

CLC Number:

TQ174

SHAO Huihui, LI Qiubo, WANG Shouzhi, WANG Zhongxin, SUN Defu, JIANG Kaize, QI Zhanguo, XU Xiangang, XU Mingsheng, ZHANG Lei. Growth of GaN Single Crystals on Sapphire Patterned-porous Thin Film Composite Substrate[J]. Journal of Inorganic Materials, 2026, 41(8): 1141-1147.

Figures/Tables 7

Fig. 1 Wet etching porous structure (a) Sapphire pattern-porous thin film composite substrate; (b) Zoomed-in view of the square box

Fig. 2 GaN crystals grown on different substrates (a) Sapphire substrate; (b) PSS; (c) Sapphire patterned-porous thin film composite substrate

Fig. 3 SEM cross-sectional images of GaN crystal grown on sapphire patterned-porous thin film composite substrate (a) Interface of sapphire and GaN growth; (b) Zoomed-in view of the interface

Fig. 4 X-ray rocking curves of the (002) and (102) planes of GaN single crystals grown on different substrates a: Sapphire substrate; b: PSS; c: Sapphire patterned-porous thin film composite substrate

Fig. 5 Raman spectra of GaN single crystals grown on different substrates a: Sapphire substrate; b: PSS; c: Sapphire patterned-porous thin film composite substrate

Fig. 6 PL spectra of GaN single crystals grown on different substrates a: Sapphire substrate; b: PSS; c: Sapphire patterned-porous thin film composite substrate

Fig. 7 CL spectra of GaN single crystals grown on different substrates (a) Sapphire substrate; (b) PSS; (c) Sapphire patterned-porous thin film composite substrate

References 34

[1]	EHRENTRAUT D, MEISSNER E, BOCKOWSKI M. Technology of gallium nitride crystal growth. Heidelberg: Springer Berlin, 2010.
[2]	HAO Y, ZHANG J F, ZHANG J C. Nitride wide bandgap semiconductor materials and electronic devices. Beijing: Science Press, 2016, 1-4: 2013.
[3]	WALTEREIT P, BRONNER W, QUAY R, et al. GaN HEMTs and MMICs for space applications. Semiconductor Science and Technology, 2013, 28(7): 074010.
[4]	UTSUMI W, SAITOH H, KANEKO H. Congruent melting of gallium nitride at 6 GPa and its application to single-crystal growth. Nature Materials, 2003, 2(11): 735.
[5]	BOCKOWSKI M. Bulk growth of gallium nitride: challenges and difficulties. Crystal Research and Technology, 2007, 42(12): 1162.
[6]	WANG B, CALLAHAN M J. Ammonothermal synthesis of III-nitride crystals. Crystal Growth & Design, 2006, 6(6): 1227.
[7]	AOKI M, YAMANE H, SHIMADA M, et al. GaN single crystal growth using high-purity Na as a flux. Journal of Crystal Growth, 2002, 242(1/2): 70.
[8]	CHO S I, CHANG K, KWON M S. Strain analysis of a GaN epilayer grown on a c-plane sapphire substrate with different growth times. Journal of Materials Science, 2007, 42(10): 3569.
[9]	CHEN K M, HUANG H H, KUO Y L, et al. Effective reduction of bowing in free-standing GaN by N-face regrowth with hydride vapor-phase epitaxy. Journal of Crystal Growth, 2009, 311(10): 3037.
[10]	MA P, WEI T B, DUAN R F, et al. Growth of thick GaN films by HVPE on sapphire substrates. Acta Electronica Sinica, 2007, 28(6): 902.
[11]	VAN DREUMEL G W G, BUIJNSTERS J G, BOHNEN T, et al. Growth of GaN on nano-crystalline diamond substrates. Diamond and Related Materials, 2009, 18(5-8): 1043.
[12]	ASHRAF H, WEYHER J L, VAN DREUMEL G W G, et al. Thick GaN layers grown by HVPE: Influence of the templates. Journal of Crystal Growth, 2008, 310(17): 3957.
[13]	QI Z G, LIU L, WANG S Z, et al. Progress in the HVPE growth and doping of GaN single crystals. Journal of Inorganic Material, 2023, 38(3): 243.
[14]	MIKAWA Y, ISHINABE T, KAGAMITANI Y, et al. Recent progress of large size and low dislocation bulk GaN growth. Gallium Nitride Materials and Devices XV, 2020, 11280: 1128002.
[15]	LIU L, YU R, WANG G, et al. Fabrication of a 2 inch free standing porous GaN crystal film and application in the growth of relaxed crack-free thick GaN. CrystEngComm, 2021, 23(41): 7245.
[16]	YU R, WANG G, SHAO Y, et al. From bulk to porous GaN crystal: precise structural control and its application in ultraviolet photo detectors. Journal of Materials Chemistry C, 2019, 7(45): 14116.
[17]	ZHANG L, DAI Y, WU Y, et al. Epitaxial growth of a self-separated GaN crystal by using a novel high temperature annealing porous template. CrystEngComm, 2014, 16(38): 9063.
[18]	LIU L, ZHANG X, WANG S, et al. Nucleation mechanism of GaN crystal growth on porous GaN/sapphire substrates. CrystEngComm, 2022, 24(10): 1840.
[19]	ZHAN D, EDGAR J. Wet etching of GaN, AlN, and SiC: a review. Materials Science and Engineering: R: Reports, 2005, 48(1): 1.
[20]	XU X, VAUDO R, FLYNN J, et al. Acid etching for accurate determination of dislocation density in GaN. Journal of Electronic Materials, 2002, 31(5): 402.
[21]	CHEN J, WANG J F, WANG H, et al. Measurement of threading dislocation densities in GaN by wet chemical etching. Semiconductor Science and Technology, 2006, 21(9): 1229.
[22]	XU Z J. Detection and analysis of semiconductors. Beijing: Science Press, 2007: 312-317.
[23]	TRIPATHY S, CHUA S J, CHEN P, et al. Micro-Raman investigation of strain in GaN and Al_xGa_1-_xN/GaN heterostructures grown on Si(111). Journal of Applied. Physics, 2002, 92(7): 3503.
[24]	GONI A R, SIEGLE H, SYASSEN K, et al. Effect of pressure on optical phonon mode and transverse effective charges in GaN and AlN. Physical Review B, 2001, 64(3): 035205.
[25]	HUANG S, ZHANG Y, LEUNG B, et al. Mechanical properties of nanoporous GaN and its application for separation and transfer of GaN thin films. ACS Applied Materials & Interfaces, 2013, 5(21): 11074.
[26]	CHAO Y, CHU R, LI R, et al. High-voltage vertical GaN Schottky diode enabled by low-carbon metal-organic chemical vapor deposition growth. Applied Physics Letters, 2016, 108(6): 062103.
[27]	HINO T, TOMIYA S, MIYAJIMA T, et al. Characterization of threading dislocations in GaN epitaxial layers. Applied Physics Letters, 2000, 76(23): 3421.
[28]	DARAKCHIEVA V, MONEMAR B, USUI A, et al. Lattice parameters of bulk GaN fabricated by halide vapor phase epitaxy. Journal of Crystal Growth, 2008, 310(5): 959.
[29]	SHAO Y, ZHANG L, HAO X, et al. Influence of GaCl carrier gas flow rate on properties of GaN films grown by hydride vapor-phase epitaxy. Journal of Alloys and Compounds, 2011, 509(21): 6212.
[30]	HEINKE H, KIRCHNER V, EINFELDT S, et al. X-ray diffraction analysis of the defect structure in epitaxial GaN. Applied Physics Letters, 2000, 77(14): 2145.
[31]	SRIKANT V, SPECK J S, CLARKE D R. Mosaic structure in epitaxial thin films having large lattice mismatch. Journal of Applied Physics, 1997, 82(9): 4286.
[32]	HEYING B, WU X H, KELLER S, et al. Role of threading dislocation structure on the X-ray diffraction peak widths in epitaxial GaN films. Applied Physics Letters, 1996, 68(5): 643.
[33]	XU W L, GAN Y H, LI Y W, et al. High rate HVPE Growth of high uniformity 6-inch GaN thick films. Journal of Synthetic Crystal, 2025, 54(1): 11.
[34]	XIA Z H, LI T K, REN G Q, et al. Dislocation density evolution study of GaN single crystal growth by ammonothermal method. Journal of Synthetic Crystal, 2024, 53(3): 480.