Characterization of foreign grain on 6H-SiC facet

Abstract

6H-SiC single crystals were grown by sublimation method. It is found that foreign grains occur frequently on the facets of the crystals. To characterize the foreign grain, a longitudinal and a sectional cut samples were prepared by standard mechanical processing method. Raman spectrum confirms that the foreign grain is actually a mis-oriented 6H-SiC grain. The surface structure of the foreign grain was studied by chemical etching and optical microscopy. It is shown that etch pits in foreign grain region take the shape of isosceles triangle, which are different from those in mono-crystalline region, and high density stacking faults are observed on the surface of the foreign grain. The orientation of foreign grain surface is determined to be (10

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4) plane by back-scattering X-ray Laue image. The X-ray powder diffraction reveals that the powder is partly graphitized after a long crystal growth run. Therefore it is believed that the loss of Si results in the formation of C inclusions, which is responsible for the nucleation of foreign grain in the facet region.

Keywords

6H-SiC / surface morphology / foreign grain / sublimation method

References

[1] OhtaniN., KatsunoM., TsugeH., FujimotoT., NakabayashiM., YashiroH., SawamuraM., AigoT., HoshinoT.. Dislocation processes during SiC bulk crystal growth [J]. Microelectronic Engineering, 2006, 83: 42-145

[2] PalmourJ. W.. Energy efficiency: The commercial pull for SiC devices [J]. Mater Sci Forum, 2006, 527/529: 1129-1134

[3] HancockJ. M.. SiC device applications: Identifying and developing commercial applications [J]. Mater Sci Forum, 2006, 527/529: 1135-1140

[4] TournierD., VellvehiM., GodignonP., MontserratJ., PlansonD., SarrusF.. Current sensing for SiC power devices [J]. Mater Sci Forum, 2006, 527/529: 1215-1218

[5] PerlinP., SwietlikT., MaronaL., CzerneckiR., SuskiT.. Fabrication and properties of GaN-based lasers [J]. J Crystal Growth, 2008, 310: 3979-3982

[6] HanR.-j., XuX.-g., HuX.-b., YuN.-s., WangJ.-y., TianY.-l., HuangW.-xia.. Development of bulk SiC single crystal grown by physical vapor transport method [J]. Optical Materials, 2003, 23: 415-420

[7] OhtaniN., FujimotoT., KatsunoM., AigoT., YashiroH.. Growth of large high-quality SiC single crystals [J]. J Crystal Growth, 2002, 237/239: 1180-1186

[8] NakamuraD.. Reduction of dislocation in the bulk growth of SiC crystals [J]. Mater Sci Forum, 2006, 527/529: 3-8

[9] HuangX. R., BlackD. R., MacranderA. T., MajJ., ChenY., DudleyM.. High-geometrical-resolution imaging of dislocation in SiC using monochromatic synchrotron topography [J]. Applied Physics Letters, 2007, 91: 231903-1-231903-3

[10] ChenY., DudleyM., LiuK. X., StahlbushR. E.. Observations of the influence of threading dislocations on the recombination enhanced partial dislocation glide in 4H-silicon carbide epitaxial layers [J]. Applied Physics Letters, 2007, 90: 171930-1-171930-3

[11] TuominenM., YakimovaR., VehanenA., JanzenE.. Defect origin and development in sublimation grown SiC boules [J]. Mater Sci Eng B, 1999, B57: 228-233

[12] XuX.-g., HuX.-b., WangJ.-y., JiangM.-hua.. Growth of mono-crystalline 6H-SiC with large diameter [J]. Journal of Synthetic Crystals, 2003, 32(5): 540-540

[13] HuX.-b., XuX.-g., WangJ.-y., HanR.-j., DongJ., LiX.-x., JiangM.-hua.. Growth and defects of 6H-SiC monocrystals [J]. J Chin Ceram Soc, 2004, 32: 248-254

[14] LiX.-x., JiangS.-z., HuX.-b., DongJ., LiJ., ChenX.-f., WangL., XuX.-g., JiangM.-hua.. Polytype control in 6H-SiC grown via sublimation method [J]. Mater Sci Forum, 2006, 527/529: 95-98

[15] WangY.-m., NingL.-n., ChenX.-f., PengY., GaoY.-q., HuX.-b., XuX.-g., JiangM.-hua.. Growth of 3-inch 6H-SiC crystal [J]. Journal of Synthetic Crystals, 2007, 36(3): 238-239

[16] JiangS.-z., ChenX.-f., XuX.-g., HuX.-b., NingL.-n., WangY.-m., LiJ., JiangM.-hua.. Optical absorption measurements on nitrogen-doped 6H-SiC single crystals [J]. J Struct Chem, 2007, 26(10): 1171-1174

[17] CiechonskiR. R., SyväjärviM., Ul-hassanJ., YakimovaR.. Structure instabilities in growth of SiC crystals [J]. J Crystal Growth, 2005, 275: e461-e466

[18] LiJ., FilipO., EpelbaumB. M., XuX., BickermannM., WinnackerA.. Growth of 4H-SiC on rhombohedral (01\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\bar 1$$\end{document}4) plane seeds [J]. J Crystal Growth, 2007, 308: 41-49

[19] SicheD., AlbrechtM., DoerschelJ., IrmscherK., RostH. J., RobbergM., SchulzD.. Effect of nitrogen doping on the formation of planar defect in 4H-SiC [J]. Materials Science Forum, 2005, 483/485: 39-42

[20] TakahashiJ., OhtaniN., KatsunoM., ShinoyamaS.. Sublimation growth of 6H- and 4H-SiC single crystals in the [1\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\bar 1$$\end{document}00] and [11\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\bar 2$$\end{document}0] directions [J]. J Crystal Growth, 1997, 181: 229-240

[21] DudleyM., HuangX. R., HuangW., PowellA., WangS., NeudeckP., SkowronskiM.. The mechanism of micropipe nucleation at inclusions in silicon carbide [J]. Applied Physics Letters, 1999, 75(6): 784-786

[22] MahajanS.. Origins of micropipes in SiC crystals [J]. Applied Physics Letters, 2002, 80(23): 4321-4323

[23] HuangX. R., DudleyM., VetterW. M., HuangW., WangS.. Direct evidence of micropipe-related pure superscrew dislocations in SiC [J]. Applied Physics Letters, 1999, 74(3): 353-355

[24] GarconI., RouaultA., AnikinM., JaussaudC., MadarR.. Study of SiC single-crystal sublimation growth conditions [J]. Mater Sci Eng B, 1995, B29: 90-93

[25] WellmannP. J., HofmannD., KadinshiL., SelderM., StraubingerT. L., WinnackerA.. Impact of SiC source material on temperature field and vapor transport during SiC PVT crystal growth process [J]. Mater Sci Forum, 2001, 353/356: 11-14

[26] HofmannD., BickermannM., EcksteinR., KolblM., MullerS. G., SchmittE., WeberA., WinnackerA.. Sublimation growth of silicon carbide bulk crystals: Experimental and theoretical studies on defect formation and growth rate augmentation [J]. J Crystal Growth, 1999, 198/199: 1005-1010

[27] KarpovD. S., BordO. V., KarpovS. Y., ZhmakinA. I., RammM. S., MakarovY. N.. Mass transport and powder source evolution in sublimation growth of SiC bulk crystals [J]. Mater Sci Forum, 2001, 353/356: 37-40

[28] MullerS. G., FrickeJ., HofmannD., HornR., NilssonO., RexerB.. Experimental and theoretical analysis of the thermal conductivity of SiC powder as source material for SiC bulk growth [J]. Mater Sci Forum, 2000, 338/342: 43-46

[29] RostH. J., DolleJ., DoerschelJ., SicheD., SchulzD., WollweberJ.. Growth related distribution of secondary phase inclusions in 6H-SiC single crystals [J]. J Crystal Growth, 2001, 225: 317-321