GaN/Al_2O_3（0001）大晶格失配异质结构的PAMOCVD外延生长
摘要
GaN作为第三代半导体材料，因其优良的特性，日益成为研究的热点，在微电子和光电子领域具有十分广阔的应用优势和发展前景。
本论文采用电子回旋共振(ECR)微波等离子体辅助金属有机物化学气相沉积(PAMOCVD)方法，以氮等离子体为氮源，研究了大晶格失配(14％)异质结GaN/Al_2O_3(0001)的低温(700℃)外延生长。为了释放因晶格失配产生的应力，以降低在GaN外延膜中引起的缺陷密度，我们对蓝宝石衬底采用了氢等离子体清洗、氮等离子体氮化以及低温生长缓冲层的方法。我们用X射线衍射(XRD)来表征晶体的结构，用原子力显微镜(AMF)来表征表面形貌。通过高能电子衍射仪(RHEED)、对实验结果进行分析比较，对GaN薄膜的清洗、氮化、缓冲层和外延生长实验参数进行了优化。XRD和AFM的结果表明，我们在蓝宝石衬底上获得了晶质良好的GaN薄膜。实验中采用了氢氮混合等离子体清洗的方法，提高了清洗的质量。文中讨论了氮化层的原子排列点阵相对于蓝宝石衬底(0001)面旋转了30°的机理；解释了在六方相的缓冲层上在较低温度下外延生长GaN的过程中出现立方相GaN的现象。另外，在分析实验流程的特点的基础上，对ESPD-U半导体薄膜生长实时监控系统作了改进。
GaN, one of the third generation semiconductor materials, becomes the hot point of research because of its excellent characteristics. It has wide potential application and development in the fields of microelectronics and optoelectronics.
This dissertation presents the investigation on the epitaxy growth with large lattice mismatch (14%) heterostructures GaN/Al2O3(0001), by an electron cyclotron resonance (ECR) plasma assisted metalorganic chemical vapor deposition (PAMOCVD) with a nitrogen plasma as a nitrogen source at low temperature (700℃) . In order to release the stresses originated from the lattice mismatch and reduce the defect densities, sapphire substrate surfaces are preprocessed by H-plasma cleaning , N-plasma nitriding and the low temperature buffer growth. The film crystal structure is characterized by XRD and the film surfaces morphology is observed by AFM. The Growth parameters were optimized and an ideal growth conditions have been got finally by comparing the results of RHEED. The result of XRD and AFM indicates that high quality GaN films were grown on sapphire. A better result is got when cleaning sapphire by hydrogen and nitrogen plasma. The mechanism of the 30?rotation of (0001) nitride plane produced by the nitridation with respect to the (0001)Al2O3 is discussed. We observed that zinc blende GaN epilayer can grow on the wurtzite GaN buffer at low temperature and give a logical explanation to it. Additionally, the real-time monitoring system of semiconductor film growth for the ESPD - U device is improved according to the characteristics of the growth procedure .
本论文采用电子回旋共振(ECR)微波等离子体辅助金属有机物化学气相沉积(PAMOCVD)方法，以氮等离子体为氮源，研究了大晶格失配(14％)异质结GaN/Al_2O_3(0001)的低温(700℃)外延生长。为了释放因晶格失配产生的应力，以降低在GaN外延膜中引起的缺陷密度，我们对蓝宝石衬底采用了氢等离子体清洗、氮等离子体氮化以及低温生长缓冲层的方法。我们用X射线衍射(XRD)来表征晶体的结构，用原子力显微镜(AMF)来表征表面形貌。通过高能电子衍射仪(RHEED)、对实验结果进行分析比较，对GaN薄膜的清洗、氮化、缓冲层和外延生长实验参数进行了优化。XRD和AFM的结果表明，我们在蓝宝石衬底上获得了晶质良好的GaN薄膜。实验中采用了氢氮混合等离子体清洗的方法，提高了清洗的质量。文中讨论了氮化层的原子排列点阵相对于蓝宝石衬底(0001)面旋转了30°的机理；解释了在六方相的缓冲层上在较低温度下外延生长GaN的过程中出现立方相GaN的现象。另外，在分析实验流程的特点的基础上，对ESPD-U半导体薄膜生长实时监控系统作了改进。
GaN, one of the third generation semiconductor materials, becomes the hot point of research because of its excellent characteristics. It has wide potential application and development in the fields of microelectronics and optoelectronics.
This dissertation presents the investigation on the epitaxy growth with large lattice mismatch (14%) heterostructures GaN/Al2O3(0001), by an electron cyclotron resonance (ECR) plasma assisted metalorganic chemical vapor deposition (PAMOCVD) with a nitrogen plasma as a nitrogen source at low temperature (700℃) . In order to release the stresses originated from the lattice mismatch and reduce the defect densities, sapphire substrate surfaces are preprocessed by H-plasma cleaning , N-plasma nitriding and the low temperature buffer growth. The film crystal structure is characterized by XRD and the film surfaces morphology is observed by AFM. The Growth parameters were optimized and an ideal growth conditions have been got finally by comparing the results of RHEED. The result of XRD and AFM indicates that high quality GaN films were grown on sapphire. A better result is got when cleaning sapphire by hydrogen and nitrogen plasma. The mechanism of the 30?rotation of (0001) nitride plane produced by the nitridation with respect to the (0001)Al2O3 is discussed. We observed that zinc blende GaN epilayer can grow on the wurtzite GaN buffer at low temperature and give a logical explanation to it. Additionally, the real-time monitoring system of semiconductor film growth for the ESPD - U device is improved according to the characteristics of the growth procedure .
引文
[1] Wang Zhanguo. Semiconductor quantum dot lasers. Physics, 2000,29(11):643
[2] Landsberg PT, et al. Evidence of k-selection in gain spectra of quantum well AlGaAs laser diode. IEEE J Quantum Electron, 1985,21(1):24
[3] Johnson W. C., Parsons J. B. and Crew M. C. Nitrogen compounds of gallium Ⅲ. gallic nitride. J. Phys., Chem., 1932,36:2561
[4] Maruska H. P.,Tietjen J. The preparation and properties of vapor-deposited single-crystal-line GaN. Appl. Phys. Lett., 1969,15(10):327-329
[5] Amano H., Sawaki N., Akasaki I. Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AIN buffer laver. Appl. Phys. Lett., 1986.48(5):353-355
[6] 梁春广，张冀．Ga N—第三代半导体的曙光．半导体学报，1999，20：89-99
[7] Amano H., Kito M., Hiramatsu K., et al. p-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation. Jpn. J. Appl. Phys.,1989,28:L2112-2114
[8] Nakamura S., Mukai T., Senoh M., and Iwasa N. Thermal annealing effects on p-type Mg-doped GaN films. Jpn. J. Appl. Phys., 1992,31:L139-142
[9] Akasaki I., Sota S., Sakai H., et al. Shortest wavelength semiconductor laser diode. Electron. Lett., 1996,32(15):1105
[10] Fasol G. Longer life for the blue laser. Science, 1997, 278 (5345):1902-1903
[11] Nakamura S., Senoh, N. Iwasa et. al. Superbright green InGaN single-quantum- well-structure light-emitting diodes. Jpn. J. Appl. Phys., 1995, 34:L1332-1335
[12] Mukai T., Nagahama S., Iwasa N. et al. In:Proc. China-Japan Workshop on Nitride Semiconductoor Materials and Devices. Shanghai, P.R. China. 2001:96
[13] Juza R. Hahn H., Zeitschr. Anorgan. Allgem., ber die Kristallstrukturen von Cu_3N, GaN und InN. Chem., 1938,239:282
[14] Shul R.J., Vawter G.A., Willison C.G., et al. Comparison of plasma etch techniques for Ⅲ-Ⅴ nitrides. Solid State Electronics., 1998,42(12):2259-2267
[15] Lakshmi E. Dielectric properties of reactively sputtered gallium nitride films .Thin Solid Films., 1981 ,83:L137
[16] Morimoto Y. Few characteristics of epitaxial GaN etching and thermal decomposition. J. Electrochem. Soc., 1974,121:1383
[17] Ito K., Amano H., Hiramatsu K., et al. Cathodoluminescence properties of undoped and Zn-doped Al_xGa_(1-x) N grown by metalorganic vapor phase epitaxy. Jpn. J. Appl. Phys., 1991,30:1604
[18] D. Basak, T. Nakanishi, S. Sakai. Reactive ion etching of GaN using BCl_3, BCl_3/Ar and BCl_3/
N_2 gas plasmas. Solid-State Electronics, 2000,44(4):725-728
[19] S. Schiestel, B. Molnal, C.A. Carosella, et al. Patterning of GaN by ion implantationdependent etching. Materials Science and Engineering, 2001, B82(1-3):111-113
[20] Lin M. E., Sverdlow B. N., and Morkoq H. Thermal stability of GaN investigated by low-temperature photoluminescence spectroscopy. Appl. Phys. Lett., 1993,63(26): 3625-3627
[21] Dingle R. and Ilegems M., Donor-acceptor pair recombination in GaN. Solid State Commun., 1971, 9:175
[22] Dingle R., Sell D. D., Stokowaki S. E., et al. Absorption, Reflectance, and Luminescence of GaN Single Crystals. Phys. Rev., 1971,B3:497-500
[23] Dingle R., Sell D. D., Stokowaki S. E., and Ilegems M., Absorption, Reflectance, and Luminescence of GaN Epitaxial Layers. Phys. Rev., 1971, B4(4):1211-1218
[24] Pankove J. I., Berkeyheiser J. E., Maruska H. P., et al. Luminescent properties of GaN. Solid State Commun., 1971,8:1051
[25] Monemar B. Fundamental energy gap of GaN from photoluminescence excitation spectra. Phys. Rev., 1974, B10(2):676-681
[26] Camphausen D. L. and Connell G. A. N. Pressure and temperature dependence of the absorption edge in GaN. J. Appl. Phys., 1971,42:4438
[27] Manchon D. D., Barker A. S., Dean P. J., et al. Optical studies of the photons and electrons in gallium nitride. Solid State Commun., 1970,8:1227
[28] Monemar B., Lagerstsdt O., and Gislason H. P., J. Properties of Zn-doped VPE-grown GaN. Ⅰ. Luminescence data in relation to doping conditions. Appl. Phys., 1980,51(1):625-639
[29] Cingolani R., Ferrara M., Lugara M.,et al. First order Raman scattering in GaN. Solid State Commun., 1986,58:823
[30] Nakamura S., Mukai T., Senoh M., et al. Si-and Ge doped GaN films grown with GaN buffers layers. Jpn. J. Appl. Phys., 1992,31:2883
[31] Nakamura S., et al. Characteristics of InGaN multi-quantum-well-structure laser diodes. Appl. Phys. Lett., 1996, 68 (23) :3269-3271
[32] Lin M E., Ma Z., Huang F Y., et al. Low resistance ohmic contacts on wide band-gap GaN .Appl. Phys. Lett., 1994, 64 (8) :1003-1005
[33] Fan Z., Mohanmmad S N., Kim W., et al. Very low resistance multilayer Ohmic contact to n-GaN . Appl. Phys. Lett., 1996,68(12):1672-1674
[34] Binari S.C., Dietrich H.B., Kelner G., et al. Electrical characterisation of Ti Schottky barriers on n-type GaN. Electron Lett., 1994,30:909
[35] Khan M.A., Shur M.S., Kuzinia J.N., et al. Temperature activated conductance in GaN/AlGaN heterostructure field effect transistors operating at temperatures up to 300℃. Appl. Phys. Lett., 1995,66(9):1083-1085
[36] Burm J., Schaff W.J., Eastman L.F. 75 GaN channel modulation doped field effect transistors. Appl. Phys. Lett.,1996,68(20):2849-2951
[37] Wu Y F., Keller B.P., Keller S., et al. Very high breakdown voltage and large transconductance realized on GaN heterojunction field effect transistors. Appl. Phys. Lett., 1996,69(10):1438-1440
[38] Khan M.A., Kuzinia J.N., Bhattarai A.R., et al. Metal semiconductor field effect transistor based on single crystal GaN. Appl. Phys. Lett., 1993,62(15):1786-1787
[39] Khan M,A., Kuzinia J.N., Olson D.T., et al. Microwave performance of a 0.25 μm gate AlGaN/GaN heterostructure field effect transistor. Appl. Phys. Lett., 1994,65(9):1121-1123
[40] Khan M.A., Kuzinia J.N., Olson D.T., et al. High-responsivity photoconductive ultraviolet sensors based on insulating single-crystal GaN epilayers. Appl. Phys. Lett., 1992, 60(23): 2917-2919
[41] Walker D., Zhang X, Kung P., et al. AlGaN ultraviolet photoconductors grown on sapphire. Appl. Phys. Lett., 1996, 68(15):2100-2101
[42] Razeghim, Rogalski A. semiconductor ultraviolet detectors. J. Appl. phy., 1996, 79(10):7433-7473
[43] Lim B. W., Chen O.C., Yang J.Y., and Khan M.A. High responsitivity intrinsic photoconductors based on Al_xGa_(1-x)N .Appl. Phys. Lett., 1996.68(26):3761-3762
[44] 臧岚，杨凯，张荣等．GaN／6H-SiC紫外探测器的光电流性质研究．半导体学报，1998，19(3)：197-201
[45] Frenkel, J. Physik Z. F., J. Chem. Phys.. 1924,26:117-122
[46] D. Walton, J. Chem. Phys. 1962,37:2182-2184
[47] 吴自勤，王兵．薄膜生长．第1版．科学出版社，2001．9：181-187
[48] Karpinski J., Jun J., Porowski S. Equilibrium pressure of N-2 over GaN and high pressure solution growth of GaN. J. Crys. Growth., 1984,66:1
[49] Morkoq H., Strite S., Gao G. B., et al. harge-band-gap SiC, Ⅲ-V nitride, and Ⅱ-Ⅵ ZnSe-based semiconductor device technologies. J. Appl. Phys.,1994,76 (3) :1363-1398
[50] Nakamura S., Senoh M., Nagahama S., et al. Continuous-wave operation of InGaN/GaN/AlGaN-based laser diodes grown on GaN substrates. Appl. Phys. Lett., 1998,72(16):2014-2016
[51] Yang H., Zheng L. X., Li J. B., et al. Cubic-phase GaN light-emitting diodes. Appl. Phys. Lett., 1999,74(17):2498-2500
[52] Lum R M, Klingert J K ,Butt B V .An integrated laboratory reactor MOCVD safety system. J. Crystal Growth, 1986,75:421-428
[53] Angel MMH,Rutherford D, Tiainen H, et al. Examination of dibenzyl aluminium and gallium azides as potential pressures to AlN and GaN. Journal of Organo metallic Chemistry, 1999,582:103-107
[54] Zhang L, Gu S L, Kuech T F, ea al. Gallium nitride growth using dielthyl gallium chloride as an alternative gallium source. Crystal Growth, 2000,213:1-9
[55] 徐科，邓佩珍，邱荣升．GaN／Al_2O_3(0001)的匹配机制及氮化的作用．中国激光，1998．4，25(4)：369-373
[56] Koukitu A, Seri H. Reaction mechanisms in MOVPE growth of GaAs. Appl. phys. Lett., 1989,49:325-327
[57] F. C. M. J. M. van Delft, A, D. van Langeveld and B. E. Nleuwenhuys. Determination of nucleation and growth mechanisms, Thin Solid Films, 1985,123:333
[58] Hajime Okumura, Krishnan Balakrishnan, Hiroshi Hamaguchi, et al. Analysis of MBE growth mode for GaN epilayers by RHEED. Journal of Crystal Growth, 1998,189/190:364-369
[59] Tohru Honda,Naoya Fujita, Kyousuke Maki, et al. Lattice constant of GaN grown on 6H-SiC by MOMBE. Applied surface Science, 2000, 159-160:468-471
[2] Landsberg PT, et al. Evidence of k-selection in gain spectra of quantum well AlGaAs laser diode. IEEE J Quantum Electron, 1985,21(1):24
[3] Johnson W. C., Parsons J. B. and Crew M. C. Nitrogen compounds of gallium Ⅲ. gallic nitride. J. Phys., Chem., 1932,36:2561
[4] Maruska H. P.,Tietjen J. The preparation and properties of vapor-deposited single-crystal-line GaN. Appl. Phys. Lett., 1969,15(10):327-329
[5] Amano H., Sawaki N., Akasaki I. Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AIN buffer laver. Appl. Phys. Lett., 1986.48(5):353-355
[6] 梁春广，张冀．Ga N—第三代半导体的曙光．半导体学报，1999，20：89-99
[7] Amano H., Kito M., Hiramatsu K., et al. p-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation. Jpn. J. Appl. Phys.,1989,28:L2112-2114
[8] Nakamura S., Mukai T., Senoh M., and Iwasa N. Thermal annealing effects on p-type Mg-doped GaN films. Jpn. J. Appl. Phys., 1992,31:L139-142
[9] Akasaki I., Sota S., Sakai H., et al. Shortest wavelength semiconductor laser diode. Electron. Lett., 1996,32(15):1105
[10] Fasol G. Longer life for the blue laser. Science, 1997, 278 (5345):1902-1903
[11] Nakamura S., Senoh, N. Iwasa et. al. Superbright green InGaN single-quantum- well-structure light-emitting diodes. Jpn. J. Appl. Phys., 1995, 34:L1332-1335
[12] Mukai T., Nagahama S., Iwasa N. et al. In:Proc. China-Japan Workshop on Nitride Semiconductoor Materials and Devices. Shanghai, P.R. China. 2001:96
[13] Juza R. Hahn H., Zeitschr. Anorgan. Allgem., ber die Kristallstrukturen von Cu_3N, GaN und InN. Chem., 1938,239:282
[14] Shul R.J., Vawter G.A., Willison C.G., et al. Comparison of plasma etch techniques for Ⅲ-Ⅴ nitrides. Solid State Electronics., 1998,42(12):2259-2267
[15] Lakshmi E. Dielectric properties of reactively sputtered gallium nitride films .Thin Solid Films., 1981 ,83:L137
[16] Morimoto Y. Few characteristics of epitaxial GaN etching and thermal decomposition. J. Electrochem. Soc., 1974,121:1383
[17] Ito K., Amano H., Hiramatsu K., et al. Cathodoluminescence properties of undoped and Zn-doped Al_xGa_(1-x) N grown by metalorganic vapor phase epitaxy. Jpn. J. Appl. Phys., 1991,30:1604
[18] D. Basak, T. Nakanishi, S. Sakai. Reactive ion etching of GaN using BCl_3, BCl_3/Ar and BCl_3/
N_2 gas plasmas. Solid-State Electronics, 2000,44(4):725-728
[19] S. Schiestel, B. Molnal, C.A. Carosella, et al. Patterning of GaN by ion implantationdependent etching. Materials Science and Engineering, 2001, B82(1-3):111-113
[20] Lin M. E., Sverdlow B. N., and Morkoq H. Thermal stability of GaN investigated by low-temperature photoluminescence spectroscopy. Appl. Phys. Lett., 1993,63(26): 3625-3627
[21] Dingle R. and Ilegems M., Donor-acceptor pair recombination in GaN. Solid State Commun., 1971, 9:175
[22] Dingle R., Sell D. D., Stokowaki S. E., et al. Absorption, Reflectance, and Luminescence of GaN Single Crystals. Phys. Rev., 1971,B3:497-500
[23] Dingle R., Sell D. D., Stokowaki S. E., and Ilegems M., Absorption, Reflectance, and Luminescence of GaN Epitaxial Layers. Phys. Rev., 1971, B4(4):1211-1218
[24] Pankove J. I., Berkeyheiser J. E., Maruska H. P., et al. Luminescent properties of GaN. Solid State Commun., 1971,8:1051
[25] Monemar B. Fundamental energy gap of GaN from photoluminescence excitation spectra. Phys. Rev., 1974, B10(2):676-681
[26] Camphausen D. L. and Connell G. A. N. Pressure and temperature dependence of the absorption edge in GaN. J. Appl. Phys., 1971,42:4438
[27] Manchon D. D., Barker A. S., Dean P. J., et al. Optical studies of the photons and electrons in gallium nitride. Solid State Commun., 1970,8:1227
[28] Monemar B., Lagerstsdt O., and Gislason H. P., J. Properties of Zn-doped VPE-grown GaN. Ⅰ. Luminescence data in relation to doping conditions. Appl. Phys., 1980,51(1):625-639
[29] Cingolani R., Ferrara M., Lugara M.,et al. First order Raman scattering in GaN. Solid State Commun., 1986,58:823
[30] Nakamura S., Mukai T., Senoh M., et al. Si-and Ge doped GaN films grown with GaN buffers layers. Jpn. J. Appl. Phys., 1992,31:2883
[31] Nakamura S., et al. Characteristics of InGaN multi-quantum-well-structure laser diodes. Appl. Phys. Lett., 1996, 68 (23) :3269-3271
[32] Lin M E., Ma Z., Huang F Y., et al. Low resistance ohmic contacts on wide band-gap GaN .Appl. Phys. Lett., 1994, 64 (8) :1003-1005
[33] Fan Z., Mohanmmad S N., Kim W., et al. Very low resistance multilayer Ohmic contact to n-GaN . Appl. Phys. Lett., 1996,68(12):1672-1674
[34] Binari S.C., Dietrich H.B., Kelner G., et al. Electrical characterisation of Ti Schottky barriers on n-type GaN. Electron Lett., 1994,30:909
[35] Khan M.A., Shur M.S., Kuzinia J.N., et al. Temperature activated conductance in GaN/AlGaN heterostructure field effect transistors operating at temperatures up to 300℃. Appl. Phys. Lett., 1995,66(9):1083-1085
[36] Burm J., Schaff W.J., Eastman L.F. 75 GaN channel modulation doped field effect transistors. Appl. Phys. Lett.,1996,68(20):2849-2951
[37] Wu Y F., Keller B.P., Keller S., et al. Very high breakdown voltage and large transconductance realized on GaN heterojunction field effect transistors. Appl. Phys. Lett., 1996,69(10):1438-1440
[38] Khan M.A., Kuzinia J.N., Bhattarai A.R., et al. Metal semiconductor field effect transistor based on single crystal GaN. Appl. Phys. Lett., 1993,62(15):1786-1787
[39] Khan M,A., Kuzinia J.N., Olson D.T., et al. Microwave performance of a 0.25 μm gate AlGaN/GaN heterostructure field effect transistor. Appl. Phys. Lett., 1994,65(9):1121-1123
[40] Khan M.A., Kuzinia J.N., Olson D.T., et al. High-responsivity photoconductive ultraviolet sensors based on insulating single-crystal GaN epilayers. Appl. Phys. Lett., 1992, 60(23): 2917-2919
[41] Walker D., Zhang X, Kung P., et al. AlGaN ultraviolet photoconductors grown on sapphire. Appl. Phys. Lett., 1996, 68(15):2100-2101
[42] Razeghim, Rogalski A. semiconductor ultraviolet detectors. J. Appl. phy., 1996, 79(10):7433-7473
[43] Lim B. W., Chen O.C., Yang J.Y., and Khan M.A. High responsitivity intrinsic photoconductors based on Al_xGa_(1-x)N .Appl. Phys. Lett., 1996.68(26):3761-3762
[44] 臧岚，杨凯，张荣等．GaN／6H-SiC紫外探测器的光电流性质研究．半导体学报，1998，19(3)：197-201
[45] Frenkel, J. Physik Z. F., J. Chem. Phys.. 1924,26:117-122
[46] D. Walton, J. Chem. Phys. 1962,37:2182-2184
[47] 吴自勤，王兵．薄膜生长．第1版．科学出版社，2001．9：181-187
[48] Karpinski J., Jun J., Porowski S. Equilibrium pressure of N-2 over GaN and high pressure solution growth of GaN. J. Crys. Growth., 1984,66:1
[49] Morkoq H., Strite S., Gao G. B., et al. harge-band-gap SiC, Ⅲ-V nitride, and Ⅱ-Ⅵ ZnSe-based semiconductor device technologies. J. Appl. Phys.,1994,76 (3) :1363-1398
[50] Nakamura S., Senoh M., Nagahama S., et al. Continuous-wave operation of InGaN/GaN/AlGaN-based laser diodes grown on GaN substrates. Appl. Phys. Lett., 1998,72(16):2014-2016
[51] Yang H., Zheng L. X., Li J. B., et al. Cubic-phase GaN light-emitting diodes. Appl. Phys. Lett., 1999,74(17):2498-2500
[52] Lum R M, Klingert J K ,Butt B V .An integrated laboratory reactor MOCVD safety system. J. Crystal Growth, 1986,75:421-428
[53] Angel MMH,Rutherford D, Tiainen H, et al. Examination of dibenzyl aluminium and gallium azides as potential pressures to AlN and GaN. Journal of Organo metallic Chemistry, 1999,582:103-107
[54] Zhang L, Gu S L, Kuech T F, ea al. Gallium nitride growth using dielthyl gallium chloride as an alternative gallium source. Crystal Growth, 2000,213:1-9
[55] 徐科，邓佩珍，邱荣升．GaN／Al_2O_3(0001)的匹配机制及氮化的作用．中国激光，1998．4，25(4)：369-373
[56] Koukitu A, Seri H. Reaction mechanisms in MOVPE growth of GaAs. Appl. phys. Lett., 1989,49:325-327
[57] F. C. M. J. M. van Delft, A, D. van Langeveld and B. E. Nleuwenhuys. Determination of nucleation and growth mechanisms, Thin Solid Films, 1985,123:333
[58] Hajime Okumura, Krishnan Balakrishnan, Hiroshi Hamaguchi, et al. Analysis of MBE growth mode for GaN epilayers by RHEED. Journal of Crystal Growth, 1998,189/190:364-369
[59] Tohru Honda,Naoya Fujita, Kyousuke Maki, et al. Lattice constant of GaN grown on 6H-SiC by MOMBE. Applied surface Science, 2000, 159-160:468-471