摘要
用热灯丝化学气相沉积方法制备硼掺杂金刚石膜,系统地研究了硼源流量、生长气压和氮气流量等工艺参数对金刚石膜生长特性的影响。金刚石膜的形貌、织构、结晶质量随硼流量和沉积气压的变化而变化,而且硼在膜中的空间分布不均匀,这些效应的综合作用导致薄膜应力状态的改变。结合霍尔效应及应力测试进一步探讨了生长掺硼金刚石薄膜的优化条件。探讨了氮对生长硼掺杂金刚石膜的晶粒尺寸(从微米到纳米)及相应场发射特性的影响。
Diamond is an promised material in many applications because of its superior properties such as high hardness and thermal conductivity, wide band gap of 5.5 eV,high optical transmittance as well as chemical inertness. Intrinsic diamond is known as an insulator with a room temperature resistivity of 1016 ?·cm. Generally B-doped diamond films can achieve a p-type semiconductor. Therefore, the B-doped diamond film has extensively application in electronic area. The effects of different experiment conditions on the growth and properties have been extensively investigated. However, there are still many problems needs more detail discussion.
In this paper, freestanding B-doped CVD diamond films were fabricated by HFCVD method with H2, CH4, and B(OCH3)3 as the precursor. The growth behavior with different texture and residual stress, as well as the boron distribution in the as grown samples were characterized by SEM, XRD, Hall and Raman spectroscope.
As demonstrated by the XRD and SEM results, the lower flow rate boron can enhanced the film quality and the growth of {110} facets, while the morphologies of the grains were dominated by {110} and {111} facets when boron source was increased up to 20 sccm. By fitting the Raman spectra, it is show that the higher B-flow rates lead to higher B-doping level in the samples. In addition, the {111} facets take up more boron atoms into the crystal than {110} facets at given boron doping levels. The variation of residual stress with increasing the B-doping level does is strongly related to film feature, boron distribution and growth conditions. Furthermore, we fabricated the B-doped freestanding diamond films at different deposition pressures with the boron flow rates that have the relative smaller stress. Observed from SEM and XRD, we find that the boron-doped films consist mainly of grains with [111] texture synthesized at lower pressures, different from the cases of mixed [111] and [110] texture at higher pressures. These optical evidences reasonably support the results of improving the quality of the films at low reaction pressures by the increase of atomic hydrogen concentration at low. The dominated [111] texture and abundance of atomic hydrogen at lower reaction pressures, as well as higher boron flow rate, provide more BHx species in ambient, making the incorporation of boron more facile in the as-grown films. Based on above Hall-effect and Raman results, the increase of impurities with increase of boron can enhance the stress.
Effect of nitrogen on the deposition and properties of boron doped diamond films were further investigated. The diamond films consist of [111] texture micro- and mixed [110] and [111] geometry nano- grains deposited with low (2 sccm) and high (10 sccm) boron flow rate, respectively. The grain size and the characteristics of Raman spectra vary insignificantly with the incorporation of nitrogen species when keep the boron flow rate constant. The electron field emission properties of the diamond films are related to the integrated effect of film composition, boron doping levels and the texture. Furthermore, it should be noting that the field emission properties of MCD films are superior to NCD films. There are two factors determine it. On one hand, the incorporation of excess boron species in NCD films substantially reduces the concentration of dangling bonds that markedly reduces the concentration of the impurity band. On the other hand, the [111] texture of MCD films possess much lower electric affinity and a higher field enhancement factor than the mixed [110] and [111] geometry NCD films.
引文
[1] Hershey. The Book of Diamonds[M]. New York: Hearthside Press, 1940.
[2]顾长志,金曾孙.金刚石膜的性质、应用及国内外研究现状[J].功能材料, 1997, 28(3):232-236.
[3] Okuzumi F. International Conference on New Diamond Science and Technology [C]. 1990:80.
[4] French P J, Muro H, Shinohara T, Nojiri H and Kaneko H. SOI pressure sensor[J]. Sensors and Actuators A: Physical, 1992, 35:17-22.
[5]戴达煌,周克崧.金刚石薄膜沉积制备工艺与应用[M].北京:冶金工业出版社, 2001
[6] Li B, Han B, Lv XY, Li HD, Wang JB, Jin ZS,IR transmittance of large sized freestanding transparent diamond films prepared by MWPCVD [J].New Carbon Materials, 2008,23:245-249,
[7] Wang QL, LüXY, Li LA, Cheng SH, Li HD, Growth and characteristics of freestanding hemispherical diamond films by microwave plasma chemical vapor deposition [J] Chinese Phys. Lett., 2010,27:047802.
[8]满卫东金刚石薄膜[J].新型碳材料,2002, 17: 77.
[9]郭西缅王岚Fe刻蚀金刚石的研究[J]复合材料学报1997(14): 2
[10] Bundy F P, Hall H T, Strong H M, Wentorf R H. Man-Made Diamonds [J]. Nature, 1955, 51:176.
[11] Derjaguin B V, Spitzyn B V, Builov L L, Kochkov A A. Diamond Crystal Synthesis on Nondiamond Substrrates [J]. Sov. Phys. Dokl., 1956, 21(11):676.
[12] Matsumoto S, Sato Y, TsuTsumi M, Setaka N. Growth of diamond particals from methane-hydrogen gas[J]. J. Mater. Sci., 1982, 17:3106.
[13] Kamo M, Sato Y, Matsumoto S, Setaka N. diamond synthesis from gas phase in microwave plasma[J]. J. Cryst. Growth, 1983, 62:642.
[14] Yan C S, Vohra Y K, Mao H K and Hemley R J. Very High Growth Rate Chemical Vapor Deposition of Single- crystal Diamond[J] . Proc. Natl. Acad. Sci. 99, 2002:12523-12525.
[15] Mokuno Y, Chayahara A., Soda Y, Horino Y, Fujimori N, Synthesizing single crystal diamond by repetition of high rate homoepitaxial growth by microwave plasma CVD[J]. Diamond Relat.Mat., 2005,14:1743
[16]金曾孙,吕宪义,曲承林等.用热解化学气相沉积法合成金刚石膜[J].吉林大学自然科学学报,No.2,1987:127.
[17] Li H D, Zou G T, Wang Q L, Cheng S H, High-rate growth and nitrogen distribution in homoepitaxial chemical vapour deposited single-crystal diamond [J] Chinese Phys. Lett., 2008:25 1803
[18] Tsuda M, Nakajima M, Oikawa S. Epitaxial growth mechanism of diamond crystal in CH4-H2 plasma. [J] J. Ame. Chem. Soc., 1986, 108: 5780-5783.
[19] Frenklach M, Spear K E. Growth mechanism of vapor-deposited diamond[J]. J. Mater. Res., 1988, 3: 133-140.
[20] Angus J C, Will H A, Stanko W S. Growth of diamond seed crystals by vapor deposition [J]. J. Appl. Phys., 1968, 39:2915-2922.
[21] Chauhan S P, Angus J C, Garden N C. Kinetics of carbon deposition on diamond power [J]. J. Appl. Phys., 1976, 47:4746-4754.
[22] Remes Z, Kromka A, Vanecek M, Ghodbane S On the reduction of the non-diamond phase in nanocrystalline CVD diamond films [J]. Diamond Relat.Mat., 2009, 18:726–729
[23]吴自勤,王兵.薄膜生长[M].北京:科学出版社, 2001
[24] Buhler J, Prior Y, Study of morphological behavior of single diamond crystals[J]. J. Crystal Growth 2000,209:779-788
[25] Lifshitz Y, Meng XM., Lee ST, Akhveldiany R, Hoffman A, Visualization of diamond nucleation and growth from energetic species [J].Phys.Rev.Lett.2004,93:056101-1
[26] Jiang X, Zhang WJ, Paul M, Klages CP, Diamond film orientation by ion bombardment during deposition[J].Appl. Phys. Lett. 1996,68:1927
[27]朱宏喜,毛卫民,冯惠平,吕反修,甲烷浓度对CVD金刚石薄膜晶体学生长过程的影响[J].无机材料学报,2007, 3:570
[28] van der Drift A., Evolutionary selection:a principle governing growth orientation in vapour deposited layers, [J].Philips Res. Rep., 22, 267(1967)
[29] Zhong XY, Chen YC, Tai NH, Lin IN, Hiller JM, Auciello O, Effect of pretreatment bias on the nucleation and growth mechanisms of ultrananocrystalline diamond films via bias enhanced nucleation and growth: An approach to interfacial chemistry analysis via chemical bonding mapping [J]. J. Appl. Phys. 2009,105:034311.
[30]白亦真,金曾孙,姜志刚,韩雪梅.热阴极辉光放电对金刚石膜沉积的影响[J].材料研究学报, 2003, 17(5):537-539.
[31] Kurihara K, Sasaki K, Kawarada M. Diamond synthesis by DC plasma jet CVD [J]. Materials and Manufacturing Processes, 1991, 6(2)241-256.
[32] Garrido JA, Nebel CE., Stutzmann M, A new acceptor state in CVD-diamond [J].Diam. Relat. Mater.2002,11:347-350
[33] Shah Z M, Mainwood A, A theoretical study of the effect of nitrogen, boron and phosphorus impurities on the growth and morphology of diamond surfaces, [J].Diam. Relat. Mater. 2008,17:1307-1310.
[34] S. Koizumi,M. Kamo,Y. Sato,H. Ozaki,T. Inuzuka,Growth and characterization of phosphorous doped {111} homoepitaxial diamond thin films [J].Appl. Phys. Lett. 71, 1065 (1997)
[35] Brazhkin VV, Ekimov EA, AG. Lyapin, Popova SV, Rakhmanina AV, Stishov SM, Lattice parameters and thermal expansion of superconducting boron doped diamonds[J].Phys. Rev. B., 2006,74:140502(R)
[36] Dai Y, Liu DH, Han SH, Huang BB, Mechanism of p-type to-n-type conductivity conversion in boron-doped diamond [J] Appl. Phys. Lett. 2004,84:1895-1897
[37] Ekimov EA, Sidorov VA., Bauer ED, Mel’nik NN, Curro NJ, Thompson JD, Superconductivity in diamond [J].Nature,2004,428:542.
[38] Morooka S, Fukui T, Semoto K, Tsubota T, Saito T, Electrical properties of homoepitaxial boron-doped diamond thin films grown by chemical vapor deposition using trimethylboron as dopant [J]. Diam Relat. Mater., 1999,8:42-47
[39] Hartmann P, Haubner R, Lux B, Effects of simultaneous boron and nitrogen addition on hot-filament CVD diamond growth [J]. Diam Relat. Mater. 1997,6:456-462
[40] Das D,Singh Raj N,Barney IT, Jackson AG,Effect of oxygen on growth and properties of diamond thin film deposited at low surface temperature [J].J. Vac. Sci. Technol. A 2008,26:1487-1496
[41] Cifre J, Puigdollers J, Polo MC, Esteve J, Trimethylboron doping of CVD diamond thin films[J].Diamond Relat.Mat.,1994,3:628-631
[42] Ushizawa K, Watanabe K, Ando T, Sakaguchi I, Boron concentration dependence of Raman spectra on {100} and {111} facets of B-doped CVDdiamond[J].Diamond Relat.Mat., 1998,7:1719-1722
[43]李春燕,掺硼金刚石膜的制备及其电学性能研究[D].长春:吉林大学原子与分子物理研究所,2006
[44] Choi I.H.,Weisbecker P,Barrat S, Bauer E, Growth of highly oriented diamond films by the MPCVD technique using CO–H2, CH4–H2 and CH4–N2–H2 gas mixtures [J].Diamond Relat.Mat.,2004, 13, 574
[45] Prawer S, Nemanich RJ. Raman spectroscopy of diamond and doped diamond[J].Philos.Trans.R.Soc.London. Ser. A 2004,362:2537
[46] Wang YG, Lau S P, Tay B K, Resonant Raman scattering studies of Fano-type interference in boron doped diamond [J]. J. Appl. Phys. 92 (2002) 7253-7256.
[47]王玉光.化学气相沉积金刚石膜特性研究[D],北京:中国科学院物理研究所,2002.
[48] Gonon P, Gheeraert E, Deneuville A, Fontaine F, Abello L, Lucazeau G, Characterization of heavily B-doped polycrystalline diamond films using Raman spectroscopy and electron spin resonance[J]. J. Appl. Phys. 1995, 78:7059-7062.
[49] Joel W, Ager III, Walukiewicz W, Matthew M. Fano interference of the Raman phonon in heavily boron doped diamond films grown by chemical vapor deposition[J].Appl. Phys. Lett. 1995,66: 616-3.
[50] Wang Y G, Li H D, Xiong Y Y, Zhang S L, Lin Z D, Feng K A,Micro-Raman scattering and photoluminescence study of boron-doped diamond films [J]. Diam. Relat. Mater. 2000, 9:1708-1711
[51] Zimmer JW, Chandler G, Sharda T,Wide area polycrystalline diamond coating and stress control by sp3 hot filament CVD reactor [J].Thin Solid Films 516 (2008) 696–699
[52] Chatterjee S, Edwards A G, Feigerie C S. The nature of stress in hot filament chemmical vapor deposited diamond thin films on WC [J]. J. Mater. Sci., 1997, 32:3355-3360.
[53] Anthony T R. Stresses generated by impurities in diamond [J]. Diam. Relat. Mater., 1995, 4:1346-1352.
[54] Cheng T K, Chii R L, How M L. Origins of the residual stress in CVD diamond films [J]. Thin Solid Films, 1996, 290-291:254-259.
[55] Ferreira N G, Abramof E,Corat E J,Trava-Airoldi V J,Residual stresses and crystalline quality of heavily boron-doped diamond films analysed by micro-Ramanspectroscopy and X-ray diffraction [J].Carbon,2003,41:1301
[56] Noyan I C, Huang T C, York B R, Residual stress/strain analysis in thin films by X-ray diffraction[J]. Critical Reviews in Solid State and Materials Sciences. 1995,20:125-177.
[57]朱宏喜,毛卫民,冯惠平,织构对CVD自支撑金刚石薄膜残余应变的影响[J].材料研究学报,2007, 21:32
[58] Ohta S, Takahashi H, Nanoscale analysis of electron irradiation enhanced diffusion process on the multilayer interfaces of W-AI203-Ti/Cu [J].Journal of Electron Microscopy 1999,48: 899-903
[59] Gielisse PJ, Handbookof Industrial Diamonds and Diamond Films, [M]. Marcel Dekker, NewYork,1998 pp. 48–88
[60] Li H D, Zhang T, Li LA, Li B, Jin ZS, Zou G T, Investigation on crystalline structure, boron distribution, and residual stresses in freestanding boron-doped CVD diamond films [J] J. Crys. Growth, 2010,312:1986.
[61] Wang WL, Polo MC, Sanchez G, Cifre J, Esteve J. Internal stress and strain in heavily boron-doped diamond films grown by microwave plasma and hot filament chemical vapor deposition[J].Appl. Phys. 1996,80:1846-5.
[62] Ralchenko VG, Smolin AA, Pereverzev VG, Obraztsova ED, Korotoushenko KG, Konov VI. Diamond deposition on steel with CVD tungsten intermediate layer[J].Diamond Relat Mater 1995,4:754.
[63] Schwarza S, Rosiwal SM, Frank M, Breidt D, Singer RF, Dependence of the growth rate, quality, and morphology of diamond coatings on the pressure during the CVD-process in an industrial hotfilament plant [J].Diam. Relat. Mater., 2002,11:589–595
[64] Yang S M, He Z T, Li Q T, Zhu D Z, Gong J L, Diamond films with preferred <110> texture by hot filament CVD at low pressure[J].Diam. Relat. Mater., 2008, 17:2075-2079.
[65] Dua A K, George V C, Friedrich M, Zahn D R, Effect of deposition parameters on different stages of diamond deposition in HFCVD technique[J].Diam. Relat. Mater. 2004, 13:74-84.
[66] Xianglin Li, James Perkins, Ramon Collazo, Robert J. Nemanich, Zlatko Sitar,Investigation of the effect of the total pressure and methane concentration on the growth rate and quality of diamond thin films grown by MPCVD, Diamond RelatedMaterials 2006,15:1784–1788
[67] Ramamurti R, Becker M, Schuelke T, Grotjohn T, Reinhard D, Boron doped diamond deposited by microwave plasma assisted CVD at low and high pressures[J].Diam. Relat. Mater. 2008, 17:481-485.
[68] Tsubota T, Fukui T, Kameta M, Saito T, Kusakabe K, Morooka S, Maeda H, Effect of total reaction pressure on electrical properties of boron doped homoepitaxial (100) diamond films formed by microwave plasma-assisted chemical vapor deposition using trimethylboron [J].Diam. Relat. Mater. 1999, 8:1079-1082.
[69] Takano Y, Nagao M, Takenouchi T, Umezawa H, Sakaguchi I, Tachiki M, Kawarada H, Superconductivity in polycrystalline diamond thin films[J].Diamond Relat. Mater., 2005,14:1936-1938
[70]吕江维冯玉杰彭鸿雁陈玉强,硼掺杂对直流热阴极CVD金刚石薄膜生长特性的影响[J].无机材料学报,2009, 24: 607-611
[71] Yu Z, Flodstr?m A, Pressure dependence of growth mode of HFCVD diamond[J].Diam. Relat. Mater. 1997,6:81-84.
[72] Liao X Z, Zhang R J, Lee C S, Lee S T, Lam Y W, The influence of boron doping on the structure and characteristics of diamond thin films[J].Diamond Relat. Mater.,1997,6:521
[73] Wang Z L, Lua C, Li J J, Gu C Z, Influence of growth pressure on the electrical properties of boron doped polycrystalline diamond films [J]. Appl. Surf. Sci.,2009, 255:9522
[74] Wang X H, Ma G H M, Zhu W, Glass J T, Bergrnan L, Turner K F, Nemanich R J, Effects of boron doping on the surface morphology and structural imperfections of diamond films[J].Diamond Relat. Mater. 1992, 1:828.
[75] Yeh W Y, Hwang J, Wu T J, Deposition of diamond films at low pressure in a planar large-area microwave surface wave plasma source, [J]. J. Vac. Sci. Technol. A. 2001,19:2835-2839.
[76] Bernard M, Deneuville A, Muret P, Non-destructive determination of the boron concentration of heavily doped metallic diamond thin films from Raman spectroscopy[J]. Diam. Relat. Mater. 2004, 13:282-286.
[77] Kiyota H, Matsushima E, Sato K, Okushi H, Ando T, Tanaka J, Kamo M, Sato Y, Electrical properties of B-doped homoepitaxial diamond (001) film[J]. Diam. Relat. Mater.1997,6:1753-1758.
[78] Qi L, Harrison J, Vohra Y, Modeling of nitrogen diborane methane hydrogen plasma for nanocrystalline diamond growth: Comparison with experimental data[J]. Diam. Relat. Mater. 2008,17:2067-2070.
[79] Chason E, Sheldon B W, Freund L B, Origin of Compressive Residual Stress in Polycrystalline Thin Films[J] Phys. Rev. Lett. 2002,88:156103
[80] Sebert W, Worner E, Fuchs F, Wild C, Koidl P ,Nitrogen induced increase of growth rate in chemical vapor deposition of diamond [J].Appl. Phys. Lett. 1996,68:759
[81] Dunst S, Sternschulte H, Schreckb M, Growth rate enhancement by nitrogen in diamond chemical vapor deposition -a catalytic effect[J].Appl. Phys. Lett. 2009,94:224101
[82] Sonoda S, Won J, Yagi H, Hatta A, Effect of nitrogen incorporation on electrical properties of boron-doped diamond films[J].Appl. Phys. Lett. 1997,70:2574
[83] Lin IN, Comparison of the effect of boron and nitrogen incorporation on the nucleation behavior and electron field emission properties of chemical vapor deposited diamond films[J]. Appl Phys Lett 2000,77:1277
[84]Roos M, Baranauskas V, Fontana M, Ceragioli H, Peterlevitz A Electron field emission from boron doped microcrystalline diamond [J].Appl. Surf. Sci. 2007, 253:7381–7386
[85] Lin IN, Hsu T, Lin GM, Chou Y P, Chen TT, Cheng HF, Improvement on electron field emission properties of nanocrystalline diamond films by co-doping of boron and nitrogen[J].J Vac. Sci. Technol. B 2003,21:1074
[86]刘才龙.用于高压电学测量的金刚石膜微电路的集成[D],吉林:吉林大学超硬材料国家重点实验室,2007.
[87] Wang Z L, Lu C, Li J J, Gu C Z, Effect of gas composition on the growth and electrical properties of boron-doped diamond films[J]. Diam Relat. Mater. 2009,18:132
[88] Jiang X, Zhang W J, Paul M, Klages C P. Diamond film orientation by ion bombardment during deposition[J]. Appl. Phys. Lett. 1996,68:1927
[89] Nesládek M, Tromson D, Mer C and Bergonzo P Superconductive B-doped nanocrystalline diamond thin films: Electrical transport and Raman spectra [J]. Appl Phys Lett 2006,88:232111
[90] Jeedigunta S, Spagnol P, Bumgarner J, Kumar A, Electrical contacts to nitrogen incorporated nanocrystalline diamond films[J].Diam Relat Mater, 2008,17:2037–2040
[91] Fayette L, Marcus B, Mermoux M, Tourillon G, Laffon K, Local order in CVD diamond films : Comparative Raman, x-ray-diffraction, and x-ray-absorption near-edge studies[J].Phys. Rev. B. 1998,57:14123.
[92] Ferrari A C, Robertson J, Origin of the 1150 cm-1 Raman mode in nanocrystalline diamond [J].Phys. Rev. B. 2001, 63:121405-1.
[93] Liang Q, Catledge S A, Vohra Y K, Effect of nitrogen addition on the morphology and structure of boron-doped nanostructured diamond films [J]. Appl. Phys. Lett. 2003,83:5047
[94] Locher R, Wagner J, Fuchs F, Wild C, Hiesinger P, Gonon P, Boron doped diamond films: electrical and optical characterization and the effect of compensating nitrogen. [J]. Mater Sci Eng B1995, 29:211
[95] Riedel M, Ristein J, Ley L ,Recovery of surface conductivity of H-terminated diamond after thermal annealing in vacuum[J].Phys. Rev. B 2004,69:125338
[96] Maier F, Riedel M, Mantel B, Ristein J, Ley L , Origin of Surface Conductivity in Diamond[J].Phys. Rev. Lett. 2000,85:3472–3475
[97] Weide J, Zhang Z, Baumann PK, Wensell MG, Bernholc J, Nemanich RJ, Negative electron affinity effects on the diamond (100) surface [J].Phys. Rev. B 1994,50:5803–5806
[98] Cui JB, Ristein J, Ley L, Electron affinity of the bare and hydrogen covered single crystal diamond (111) surface[J].Phys. Rev. Lett. 1998,81: 429–432
[99] Li SQ, Liang Y X, Wang T H Nonlinear characteristics of the Fowler Nordheim plot for field emission from In2O3 nanowires grown on InAs substrate. [J].Appl. Phys. Lett. 2006, 88:053107
[100] Lin I N, Hsu T, Lin G M, Chou Y P, Chen T T, Cheng H F[J]. J Vac Sci Technol B 2003, 21:1074
[101] Zapol P, Sternberg M, Curtiss L A, Frauenheim T, Gruen D M [J]. Phys Rev B 2001,65:045403
[102] Pradhan D, Lin I N, Grain Size Dependent Diamond Nondiamond Composite Films: Characterization and Field-Emission Properties[J]. Appl. Mater. Interfaces 2009,1:1444
[103] Ikeda T, Teii K, Origin of low threshold field emission fromnitrogen-incorporated nanocrystalline diamond films[J]. Appl. Phys. Lett. 2009,94:143102
[104] Zhou D, Krauss A R, Qin L C, McCauley T G, Gruen D M, Synthesis and electron field emission of nanocrystalline diamond thin films grown from N2/CH4 microwave plasmas [J]. J. Appl. Phys. 1997,82:4546
[105] Chen YH, Hu CT, Lin IN, Defect structure and electron field-emission properties of boron-doped diamond films[J]. Appl Phys Lett., 1999,75:2857
[106] Ji H, Jin Z S, Wang J Y, Lu X Y, Gu C Z, Liu B B, Jin W C, Gao C X Field emission characteristics of diamond films with different surface morphologies [J]. J Vac Sci Technol B, 1999,17: 684