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Patterning of sapphire substrates via a solid state conversion process

  • Hyoungjoon Park (a1), Helen M. Chan (a1) and Richard P. Vinci (a1)


Nanopatterned sapphire substrates offer the potential for improved performance of devices based on III-V nitrides, e.g., light-emitting diodes and laser diodes. Due to the chemical stability and hardness of sapphire, however, surface patterning is a time-consuming and expensive process. Therefore, a novel method was utilized, whereby a surface coating of Al was deposited on a sapphire substrate and patterned into an array of square mesas using e-beam lithography. The lateral dimensions of each mesa were approximately 400 × 400 nm, and the average height was approximately 100 nm. The metallic film was subsequently subjected to an oxidation treatment at 450 °C for 24 h (a heat treatment which had previously been shown to minimize hillock formation). For the second heat treatment, which is necessary to induce migration of the sapphire interface and hence achieve solid state conversion, a range of temperatures (800–1350 °C) was explored. Results showed that for a heat-treatment time of 1 h, pattern retention was achieved for annealing temperatures less than or equal to 1250 °C. Successful epitaxial conversion of the patterned mesas to sapphire was confirmed using electron backscatter diffraction.



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1.Orton, J.W. and Foxon, C.T.: Group III nitride semiconductors for short wavelength light-emitting devices. Rep. Prog. Phys. 61, 1 (1998).
2.Nakamura, S.: InGaN-based laser diodes. Ann. Rev. Mater. 28, 125 (1998).
3.Kobayashi, H., Toyoda, Y., Ohki, Y., Matsuda, N. and Akasaki, I.: GaN blue light emitting diode (LED). National Tech. Rep. 28, 83 (1982).
4.Akasaki, I.: Renaissance and progress in nitride semiconductors. J. Cryst. Growth 198, 885 (1999).
5.Pilkuhn, M.: New development in semiconductor light emitting diodes for short wavelength. VDE-Verlag, Itg-Fachbericht 150, 71 (1998).
6.Morkoc, H.: Defects in and applications of III-V nitride semiconductors. Mater. Sci. Forum 239, 119 (1997).
7.Keller, S., Keller, B.P., Wu, Y-F., Heying, B., Kapolnek, D., Speck, J.S., Mishra, U.K. and Denbaars, S.P.: Influence of sapphire nitridation on properties of gallium nitride grown by metalorganic chemical vapor deposition. Appl. Phys. Lett. 68, 1525 (1996).
8.Rosner, S.J., Carr, E.C., Ludowise, M.J., Girolami, G. and Erikson, H.I.: Correlation of cathodoluminescence inhomogeneity with microstructural defects in epitaxial GaN grown by metalorganic chemical-vapor deposition. Appl. Phys. Lett. 70, 420 (1997).
9.Hansen, M., Fini, P., Craven, M., Heying, B., Speck, J.S. and Denbaars, S.P.: Morphological and optical properties of InGaN laser diodes on laterally overgrown GaN. J. Cryst. Growth 234, 623 (2002).
10.Sasaoka, C., Sunakawa, H., Kimura, A., Nido, M., Usui, A. and Sakai, A.: High-quality InGaN MQW on low-dislocation-density GaN substrate grown by hydride vapor- phase epitaxy. J. Cryst. Growth 189, 61 (1998).
11.Nakamura, S.: The roles of structural imperfections in InGaN-based blue light-emitting diodes and laser diodes. Science 281, 956 (1998).
12.Fretas, J.A. Jr., Nam, O-H. and Davis, R.F.: Optical characterization of lateral epitaxial overgrown GaN layer. Appl. Phys. Lett. 72, 2990 (1998).
13.Kidoguchi, I., Ishibashi, A., Sugahara, G. and Ban, Y.: Air-bridged lateral epitaxial overgrowth of GaN thin films. Appl. Phys. Lett. 76, 3768 (2000).
14.Nakamura, S., Senoh, M., Nagahama, S., Iwasa, N., Yamada, T., Masushita, T., Kiyoku, H., Sugimoto, Y., Kozaki, T., Umemoto, H., Sano, M. and Chocho, K.: InGaN/GaN/AlGaN-based laser diodes with modulation-doped strained-layer superlattices grown on an epitaxially overgrown GaN substrate. Appl. Phys. Lett. 72, 211 (1998).
15.Mukai, T., Takekawa, K. and Nakamura, S.: InGaN-based blue light-emitting diodes grown on epitaxially laterally overgrown GaN substrates. Jpn. J. Appl. Phys. 37, L839 (1998).
16.Rokowski, A.M., Miraglia, P.Q., Preble, E.A., Einfeldt, S. and Davis, R.F.: Surface instability and associated roughness during conventional and pendeo-epitaxial growth of GaN (0001) films via MOVPE. J. Cryst. Growth 241, 141 (2002).
17.Zheleva, T., Smith, S., Thomson, D. and Linthicum, K.: Pendeo-epitaxy: A new approach for lateral growth of gallium nitride films. J. Electron. Mater. 28 5 (1995).
18.Zubia, D. and Hersee, S.D.: Nanoheteroepitaxy: The application of nanostructuring and substrate compliance to the heteroepitaxy of mismatched semiconductor materials. J. Appl. Phys. 85, 6492 (1999).
19.Zubia, D., Zaidi, S.H., Hersee, S.D. and Brueck, S.R.J.: Nanoheteroepitaxy: Nanofabrication route to improved epitaxial growth. J. Vac. Sci. Technol. B 18, 3514 (2000).
20.Kitayama, M., Powers, J.D., Kulinsky, L. and Glaeser, A.M.: Surface and interface properties of alumina via model studies of microdesigned interfaces. J. Eur. Ceram. Soc. 19, 2191 (1999).
21.Hsu, Y.P., Chang, S.J., Su, Y.K., Sheu, J.K., Lee, C.T., Wen, T.C., Wu, L.W., Kuo, C.H., Chang, C.S. and Shei, S.C.: Lateral epitaxial patterned sapphire InGaN/GaN MQW LEDs. J. Cryst. Growth 261, 466 (2004).
22.Chang, S.J., Lin, Y.C., Su, Y.K., Chang, C.S., Wen, T.C., Shei, S.C., Ke, J.C., Kuo, C.W., Chen, S.C. and Liu, C.H.: Nitride-based LEDs fabricated on patterned sapphire substrates. Solid-State Electron. 47, 1539 (2003).
23.Park, H. and Chan, H.M.: A novel process for the generation of pristine sapphire surfaces. Thin Solid Films 422, 135 (2002).
24.Beck, A.F., Heine, M.A., Caule, E.J. and Pryor, M.J.: The kinetics of the oxidation of Al in oxygen at high temperature. Corros. Sci. 7, 1 (1967).
25.Maruyama, T. and Komatsu, W.: Surface diffusion of single-crystal Al2O3 by scratch-smoothing method. J. Am. Ceram. Soc 58, 338 (1975).
26.Bennison, S.J. and Harmer, M.P.: Effect of magnesia solute on surface diffusion in sapphire and the role of magnesia in the sintering of alumina. J. Am. Ceram. Soc. 73, 833 (1990).
27.Glaeser, A.M.: Investigating surface transport in ceramics using microdesigned interfaces, in Ceramic Interfaces: Properties and Applications (Inst. Mater. London, U.K., 1998), p. 241.
28.Bonzel, H.P.: Surface morphologies: Transient and equilibrium shapes. Interface Sci. 9, 21 (2001).
29.Mullins, W.W.: Flattening of nearly plane solid surfaces due to capillarity. J. Appl. Phys. 80, 77 (1959).
30.Bonzel, H.P. and Mullins, W.W.: Smoothing of perturbed vicinal surfaces. Surf. Sci. 350, 285 (1996).
31.Ren, S.X., Kenik, E.A., Alexander, K.B. and Goyal, A.: Exploring spatial resolution in electron back-scattered diffraction experiments via Monte Carlo simulation. Microsc. Microanal. 4, 15 (1998).
32.Kanaya, K. and Okayama, S.: Penetration and energy loss theory of electrons in solid targets. J. Phys. D Appl. Phys. 5, 43 (1972).


Patterning of sapphire substrates via a solid state conversion process

  • Hyoungjoon Park (a1), Helen M. Chan (a1) and Richard P. Vinci (a1)


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