实验目的在于解决GaN外延层中六方形腐蚀坑起源问题存在的分歧,并利用腐蚀法准确地估计GaN的位错密度.大量对熔融KOH腐蚀GaN过程中表面形貌的演化以及温度和时间对腐蚀结果影响的实验结果表明,位错类型与腐蚀坑三维形状相对应,而与腐蚀坑大小无关,极性是GaN不同种类位错的腐蚀坑具有不同形状的决定性因素.使所有缺陷都显示出来所需的腐蚀温度和时间呈反比关系.腐蚀法估算GaN位错密度的准确性取决于优化的腐蚀条件和合理的微观观测方法.
The purpose of this paper is to deal with the controversy in the literature about the origins of the hexagonal-shaped etch pits in GaN epilayers formed by wet-chemical etching, and get a better estima-tion of dislocation densities. Intensive observations of GaN etching by molten KOH are focused on the morphology evolution during etching and the dependence of etching on time and temperature. It is the three-dimensional shape of etch pits that could be correlated with the dislocation type, instead of the size as many literatures presented, and polarity is found to be responsible for the formation of these different etch pit shapes. In addition, the needed etching time to reveal all the dislocations decreases with in-creasing needed temperature. A combination of the optimum etching condition and the proper microscopy measurement leads to a reliable evaluation of dislocation densities in GaN.
参考文献
| [1] | Wang C M;Wang X L;Hu G X et al.The effect of AIN growth time on the electrical properties of Al0.38 Ga0.62 N/AlN/GaN HEMT structures[J].Journal of Crystal Growth,2006,289:415-418. |
| [2] | Visconti P;Jones K M;Resbehikov M A et al.Disloca-tion density in GaN determined by photoclectrochemical and hot wet etching[J].Applied Physics Letters,2000,77:3532-3534. |
| [3] | Zhuang D;Edgar J H .wet etching of GaN,AlN,and SiC:a review[J].Materials Science and Engineering B:Solid State Materials for Advanced Technology,2005,48:1-46. |
| [4] | Wu XH.;Kapolnek D.;Keller S.;Keller B.;Denbaars SP.;Speck JS.;Brown LM. .DEFECT STRUCTURE OF METAL-ORGANIC CHEMICAL VAPOR DEPOSITION-GROWN EPITAXIAL (0001) GAN/AL2O3[J].Journal of Applied Physics,1996(6):3228-3237. |
| [5] | Speck J S .Role of the threading dislocations in the physical properties of GaN and its alloys[J].Materials Science Forum,2001,353-356:769-778. |
| [6] | J. L. Weyher;G. Kamler;G. Nowak;J. Borysiuk;B. Lucznik;M. Krysko;I. Grzegory;S. Porowski .Defects in GaN single crystals and homoepitaxial structures[J].Journal of Crystal Growth,2005(1):135-142. |
| [7] | T. C. Wen;W. I. Lee;J. K. Sheu .Observation of dislocation etch pits in epitaxial lateral overgrowth GaN by wet etching[J].Solid-State Electronics,2002(4):555-558. |
| [8] | Xueping Xu;R.P.Vaudo;J.Flynn;G.R.Brandes .Acid etching for accurate determination of dislocation density in GaN[J].Journal of Electronic Materials,2002(5):402-405. |
| [9] | Shiojima;Kenji .Atomic force microscopy and transmission electron microscopy observation of KOH etched GaN sur-faces[J].Journal of Vacuum Science and Technology B:Microelectronics and Nanometer Structures,2000,18(01):37-40. |
| [10] | Youtsey C.;Adesida I.;Romano LT. .Gallium nitride whiskers formed by selective photoenhanced wet etching of dislocations[J].Applied physics letters,1998(6):797-799. |
| [11] | Youtsey C;Romano L T;Molnar R J et al.Rapic evalua-tion of dislocation densities in n type GaN films using pho-tocnhanced wet etching[J].Applied Physics Letters,1999,74(23):3537-3540. |
| [12] | Stocker D A;Schubert E F;Redwing J M .crystallograph-ic wet chemical etching of GaN[J].Applied Physics Letters,1998,73(18):2654-2657. |
| [13] | Ono Y.;Takada T.;Inui K.;Matsue T.;Iyechika Y. .Reduction of etch pit density on GaN by InGaN-strained SQW[J].Journal of Crystal Growth,1998(0):133-137. |
| [14] | Yamamoto K.;Egawa T.;Jimbo T.;Umeno M.;Ishikawa H. .EBIC observation of n-GaN grown on sapphire substrates by MOCVD[J].Journal of Crystal Growth,1998(0):575-579. |
| [15] | Kozawa T;Kachi T;Ohwaki T et al.Dislocation etch pits in CaN epitaxial layers grown on sapphire substrates[J].Journal of the Electrochemical Society,1996,143(01):L17-19. |
| [16] | Hong SK.;Park HS.;Park Y.;Yoon SY.;Kim YI.;Kim BJ. .Evaluation of nanopipes in MOCVD grown (0001) GaN/Al2O3 by wet chemical etching[J].Journal of Crystal Growth,1998(1/2):275-278. |
| [17] | S. K. Hong;T. Yao;B. J. Kim .Origin of hexagonal-shaped etch pits formed in (0001) GaN films[J].Applied physics letters,2000(1):82-84. |
| [18] | Visconti P;Huang D;Reshchikov M A et al.Investiga-tion of defects and polarity in GaN using hot wet etching AFM TEM and convergent beam electron diffraction[J].Physical Status Solidi B,2001,228(02):513-515. |
| [19] | Visconti P.;Huang D.;Yun F.;Reshchikov MA.;King T.;Cingolani R. Jasinski J.;Liliental-Weber Z.;Morkoc H. .Rapid delineation of extended defects in GaN and a novel method for their reduction[J].Physica Status Solidi, A. Applied Research,2002(1):5-14. |
| [20] | Visconti P.;Huang D.;Reshchikov MA.;Yun F.;Cingolani R.;Smith DJ. Jasinski J.;Swider W.;Liliental-Weber Z.;Morkoc H. .Investigation of defects and surface polarity in GaN using hot wet etching together with microscopy and diffraction techniques[J].Materials Science & Engineering, B. Solid-State Materials for Advanced Technology,2002(1/3):229-233. |
| [21] | GaN nanotip pyramids formed by anisotropic etching[J].Journal of Applied Physics,2003(1):650-653. |
| [22] | Zhou Yu;Wu Gaohui.Material analysis and test tech-niques[M].哈尔滨:哈尔滨理工大学,2004 |
| [23] | Hull D;Bacon D J.Introduction to dislocations[M].北京:科学出版社,1990 |
| [24] | Friedel J.Dislocations[M].北京:科学出版社,1980 |
| [25] | D. Huang;P. Visconti;K. M. Jones;M. A. Reshchikov;F. Yun;A. A. Baski;T. King;H. Morkoc .Dependence of GaN polarity on the parameters of the buffer layer grown by molecular beam epitaxy[J].Applied physics letters,2001(26):4145-4147. |
| [26] | T Palacios;F Calle;M Varela .Wet etching of GaN grown by molecular beam epitaxy on Si(111)[J].Semiconductor Science and Technology,2000(10):996-1000. |
| [27] | Li DS.;Yoshimura K.;Suzuki Y.;Fukuda Y.;Fuke S.;Sumiya M. .Characteristics of the GaN polar surface during an etching process in KOH solution[J].Physica Status Solidi, A. Applied Research,2000(1):357-362. |
| [28] | Dongsheng Li;M. Sumiya;S. Fuke;Deren Yang;Duanlin Que;Y. Suzuki;Y. Fukuda .Selective etching of GaN polar surface in potassium hydroxide solution studied by x-ray photoelectron spectroscopy[J].Journal of Applied Physics,2001(8):4219-4223. |
| [29] | B.J. KIM;J.W. LEE;H.S. PARK .Wet Etching of (0001 ) GaN/Al_2O_3 Grown by MOVPE[J].Journal of Electronic Materials,1998(5):L32-L34. |
| [30] | Kapoinek D;Wu X H;Heying B et al.Structural evolu-tion in epitaxial metalorganic chemical vopor deposition grown GaN films on sapphire[J].Applied Physics Letters,1995,67(11):1541-1543. |
| [31] | Hansen PJ.;Erickson AN.;Tarsa EJ.;Kozodoy P.;Brazel EG. Ibbetson JP.;Mishra U.;Narayanamurti V.;DenBaars SP.;Speck JS.;Strausser YE. .Scanning capacitance microscopy imaging of threading dislocations in GaN films grown on (0001) sapphire by metalorganic chemical vapor deposition[J].Applied physics letters,1998(18):2247-2249. |
| [32] | Baia J;Wanga T;Parbrooka P J et al.A study of dislo-cations in AIN and GaN films grown on sapphire substrates[J].Journal of Crystal Growth,2005,282:290-295. |
| [33] | Yue Jun Sun;Oliver Brandt;Tian Yu Liu;Achim Trampert;Klaus H. Ploog;Jurgen Blasing;Alois Krost .Determination of the azimuthal orientational spread of GaN films by x-ray diffraction[J].Applied physics letters,2002(26):4928-4930. |
| [34] | Fantner E B;Ryan T;Schurman M et al.XRD and opti-cal characterization of GaN and associated substrate mate-rials[J].Materials Science Forum,2000,321-324:1056-1060. |
| [35] | H. Heinke;V. Kirchner;S. Einfeldt .X-ray diffraction analysis of the defect structure in epitaxial GaN[J].Applied physics letters,2000(14):2145-2147. |
| [36] | Zheng X H;Chen H;Yan Z B .Determination of twist an-gle of in-plane mosaicspread of GaN films by high-res-olution X-ray diffraction[J].Journal of Crystal Growth,2003,255:63-68. |
| [37] | Metzger T.;Born E.;Ambacher O.;Stutzmann M.;Stommer R. Schuster M.;Gobel H.;Christiansen S.;Albrecht M.;Strunk HP.;Hopler R. .Defect structure of epitaxial GaN films determined by transmission electron microscopy and triple-axis X-ray diffractometry[J].Philosophical Magazine.A.Physics of condensed matter, defects and mechanical properties,1998(4):1013-1025. |
| [38] | De keijser Th H;Mittemeijer E J;Rozendaal H C F .The determination of crystallite size and lattice strain parame-ters in conjunction with the profile refinement method for the determination of crystal structures[J].Journal of Applied Crystallography,1983,16:309-316. |
| [39] | Hordon M J;Averbach B L .X-ray measurements of dis-location density in deformation copper and aluminum sin-gle crystals[J].Acta Metallurgica,1961,9:237-251. |
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