Impurities of Homoepitaxy Interface on Bulk GaN Substrate

Abstract

Abstract: Homoepitaxy on bulk GaN substrate has significant advantages. However, accumulation of impurities on the regrowth interface has always been a problem that plagues the wide application of homoepitaxial, especially for electronic devices, which will bring channel effect, and for laser applications, which will affect the light field distribution in the resonator. In this paper, the in-situ treatment of metal-organic chemical vappor deposition (MOCVD) growth has achieved effective inhibition of the accumulation of interfacial impurities. The study found that the main impurities on the interface are C, H, O and Si, of which C, H, O can be removed by in-situ thermal cleaning. The problem of interface Si accumulation is mainly caused by exposure to air during the preservation of the substrate. During the growth process, the etching of the substrate by the carrier gas will release impurity elements which will accumulate at the regrowth interface. High Si background content and unstable N face of the GaN substrate are also sources of regrowth interface impurities. This paper systematically clarified the formation mechanism of interface impurities and proposed solutions.

Key words: GaN substrate, regrow interface, interfacial impurity, source of impurity, homoepitaxy, Si accumulation

CLC Number:

O734
TN304

SHAO Kaiheng, XIA Songyuan, ZHANG Yumin, WANG Jianfeng, XU Ke. Impurities of Homoepitaxy Interface on Bulk GaN Substrate[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2021, 50(3): 441-446.

References

[1] RAMOS I,RUIZ LAVÍN M N, GARCÍA J A, et al. GaN microwave DC-DC converters[J]. IEEE Transactions on Microwave Theory and Techniques, 2015, 63(12): 4473-4482.
[2] TREW R J, BILBRO G L, KUANG W, et al.Microwave AlGaN/GaN HFETs[J]. IEEE Microwave Magazine, 2005, 6(1): 56-66.
[3] LIU Z R, WANG J F, GU H, et al.High-voltage vertical GaN-on-GaN Schottky barrier diode using fluorine ion implantation treatment[J]. AIP Advances, 2019, 9(5): 055016.
[4] WANG W F, WANG J F, ZHANG Y M, et al.Fabrication and characterization of vertical GaN Schottky barrier diodes with boron-implanted termination[J]. Chinese Physics B, 2020, 29(4): 047305.
[5] CHUNG J W, HOKE W E, CHUMBES E M, et al.AlGaN/GaN HEMT with 300-GHz f_max[J]. IEEE Electron Device Letters, 2010, 31(3): 195-197.
[6] LIU X K, WANG H Y, CHIU H C, et al.Analysis of the back-barrier effect in AlGaN/GaN high electron mobility transistor on free-standing GaN substrates[J]. Journal of Alloys and Compounds, 2020, 814: 152293.
[7] AZIZE M, BOUGRIOUA Z, GIBART P.Inhibition of interface pollution in AlGaN/GaN HEMT structures regrown on semi-insulating GaN templates[J]. Journal of Crystal Growth, 2007, 299(1): 103-108.
[8] CORDIER Y, AZIZE M, BARON N, et al.Subsurface Fe-doped semi-insulating GaN templates for inhibition of regrowth interface pollution in AlGaN/GaN HEMT structures[J]. Journal of Crystal Growth, 2008, 310(5): 948-954.
[9] WONG Y Y, HUANG W C, TRINH H D, et al.Effect ofnitridation on the regrowth interface of AlGaN/GaN structures grown by molecular beam epitaxy on GaN templates[J]. Journal of Electronic Materials, 2012, 41(8): 2139-2144.
[10] LIU J P, RYOU J H, YOO D, et al.III-nitride heterostructure field-effect transistors grown on semi-insulating GaN substrate without regrowth interface charge[J]. Applied Physics Letters, 2008, 92(13): 133513.
[11] CRUZ S C, KELLER S, MATES T E, et al.Crystallographic orientation dependence of dopant and impurity incorporation in GaN films grown by metalorganic chemical vapor deposition[J]. Journal of Crystal Growth, 2009, 311(15): 3817-3823.
[12] USIKOV A, SOUKHOVEEV V, KOVALENKOV O, et al. Accumulation ofbackground impurities in hydride vapor phase epitaxy grown GaN layers[J]. Japanese Journal of Applied Physics, 2013, 52(8S): 08 JB22.
[13] CORDIER Y, AZIZE M, BARON N, et al.AlGaN/GaN HEMTs regrown by MBE on epi-ready semi-insulating GaN-on-sapphire with inhibited interface contamination[J]. Journal of Crystal Growth, 2007, 309(1): 1-7.
[14] KOBLMÜLLER G, CHU R M, RAMAN A, et al. High-temperature molecular beam epitaxial growth of AlGaN/GaN on GaN templates with reduced interface impurity levels[J]. Journal of Applied Physics, 2010, 107(4): 043527.
[15] EICHFELD S M, WON D, TRUMBULL K, et al.Dual temperature process for reduction in regrowth interfacial charge in AlGaN/GaN HEMTs grown on GaN substrates[J].Physica Status Solidi C, 2011, 8(7/8): 2053-2055.
[16] HITE J K, MASTRO M A, LUNA L E, et al.(invited) understanding interfaces in homoepitaxial GaN growth[J]. ECS Transactions, 2018, 86(9): 15-19.
[17] TAJIMA J, HIKOSAKA T, KURAGUCHI M, et al.Improvement of electrical characteristics in regrown AlGaN/GaN MOSFETs by suppression of the residual interface charge[J]. Journal of Crystal Growth, 2019, 509: 129-132.
[18] ACOSTA R E, MORALES A L, DUQUE C M, et al.Optical absorption and refractive index changes in a semiconductor quantum ring: electric field and donor impurity effects[J]. Physica Status Solidi (b), 2016, 253(4): 744-754.
[19] XU K, WANG M, ZHOU T F, et al.Homoepitaxy of GaN light-emitting diodes[M]//Light-Emitting Diodes. Cham: Springer International Publishing, 2019: 93-132.
[20] DEAN J A.Lange’s handbook of chemistry[M]. McGraw-Hill New York, 1992.
[21] YEH Y H, CHEN K M, WU Y H, et al.Hydrogen etching of GaN and its application to produce free-standing GaN thick films[J]. Journal of Crystal Growth, 2011, 333(1): 16-19.
[22] LI D S, SUMIYA M, FUKE S, et al.Selective etching of GaN polar surface in potassium hydroxide solution studied by X-ray photoelectron spectroscopy[J]. Journal of Applied Physics, 2001, 90(8): 4219-4223.
[23] MASTRO M A, KRYLIOUK O M, ANDERSON T J, et al.Influence of polarity on GaN thermal stability[J]. Journal of Crystal Growth, 2005, 274(1/2): 38-46.
[24] OSHIMURA Y, TAKEDA K, SUGIYAMA T, et al.AlGaN/GaN HFETs on Fe-doped GaN substrates[J]. Physica Status Solidi C, 2010, 7(7/8): 1974-1976.